Prevalence of subclinical infectious agents in a blood donor population tested on every donation

OBJECTIVES

This study aimed to assess the prevalence of blood-borne infectious agents in healthy, client-owned dogs from a blood donor population in Portugal and Spain, and to address the importance of a screening protocol on every donation.

MATERIALS AND METHODS

Client-owned healthy dogs were tested before each donation on a veterinary blood bank. Blood samples from new potential donors, and from regular donors, were tested by real-time polymerase chain reaction for Leishmania species, Ehrlichia species, Brucella species, Babesia species and Anaplasma species Serological tests were also performed for Leishmania species, Ehrlichia species and Dirofilaria immitis. All donors were tested for every infectious agent in each donation.

RESULTS

The study found that out of a total of 8036 donors and 35,120 samples tested, 3.9% of blood donors tested positive for at least one of the agents, with the most prevalent being Anaplasma species (2.1%). Serological tests also revealed positive results in 14.0% of donors, with the highest percentage for Leishmania species (7.7%). Moreover, the study found that 28.2% of positive results were from dogs with negative results in donations performed 3 to 12 months before, and 18.0% of positive results were recent infections.

CLINICAL SIGNIFICANCE

These findings indicate a high prevalence of infectious agents in seemingly healthy, selected dogs eligible to become blood donors in the Iberian Peninsula, highlighting the importance of regular testing on every donation. This study emphasises the importance of a regular screening protocol for every donation instead of annual testing, as is commonly performed in veterinary medicine.

Rare RNF213 variant in adolescent with moyamoya disease

INTRODUCTION

Moyamoya disease is a progressive steno-occlusive disease of the major intracranial arteries. Affected individuals are at risk for intracranial hemorrhagic or ischemic stroke, cognitive impairment, and developmental delays. Several susceptibility genes have been identified. The p.R4810K variant in the RNF213 gene has been identified in 95% of patients with familial moyamoya disease.

CASE REPORT

We present the case of a 15-year-old adolescent girl who presented with chief complaints of dysgraphia, lack of coordination in the right hand, with two months of evolution. Cerebral magnetic resonance imaging revealed several ischemic lesions with different rates of evolution and magnetic resonance angiography showed multiple subocclusive stenoses. In the study of the sequences of the coding regions and intronic flanking regions (±8 bp) of the RNF213 gene, the variant c.12185G>A, p.(Arg4062Gln) was detected in heterozygosity in the RNF213 gene. This result indicates that the patient is heterozygous for the c.12185G>A, p.(Arg4062Gln) variant in the RNF213 gene. The detected variant has already been reported in the literature as a founder variant in the Asian population, associated with moyamoya syndrome. This variant is described in ClinVar as a variant of unknown clinical significance? Furthermore, it is not described in population databases (dbSNP, ESP, gnomAD).

CONCLUSION

To our knowledge, the p.(Arg406262Gln) variant has been reported in three Japanese moyamoya disease patients and one European. Therefore, our patient was the second European moyamoya disease patient with this variant identified.

Microvascular dysfunction is associated with impaired myocardial work in obstructive and nonobstructive hypertrophic cardiomyopathy: a multimodality approach

Introduction

Myocardial work is a dynamic non-invasive method for assessing myocardial deformation. Microvascular dysfunction is a hallmark of hypertrophic cardiomyopathy (HCM). We hypothesized that there is an association between impaired myocardial work, evaluated by echocardiography, and left ventricular (LV) ischemia, detected by cardiac magnetic resonance (CMR).

Methods

Prospective assessment of HCM patients' (P) myocardial strain parameters with 2D speckle-tracking echocardiography. All P underwent CMR protocol (1.5-T) for the analysis of stress perfusion and late gadolinium enhancement (LGE). Perfusion defects were quantified as burden of ischemia (% of LV mass). Results were stratified according to obstructive (oHCM) and nonobstructive (nHCM) HCM as well as according to the presence of significant replacement fibrosis (LGE of ≥15% or <15% of LV mass). Multivariate regression analyses were used to explore the relation between myocardial work and the burden of ischemia.

Results

75 P with HCM (63% male, age 55±15 years), 61% with asymmetric septal LVH, 29% with apical LVH, 8% with concentric LVH and 28% exhibiting LV outflow tract obstruction (mean maximal LVOT gradient of 89±60 mmHg). Perfusion defects were found in 68 P (90.7%), with a mean of 22.5±16.9% of LV mass and 29 P (38.7%) had LGE ≥15% of LV mass.

A lower global work index (GWI) significantly correlated with higher burden of myocardial perfusion defects (r=−0.520, β-estimate −0.019, 95% CI −0.028 to −0.010, p<0.001). Likewise, impaired values of global work efficiency (GWE) were linked to higher percentage of hypoperfusion (r=−0.477, β-estimate −0.713, 95% CI −1.250 to −0.176, p<0.001). Moreover, impaired global constructive work (GCW) (r=−0.519, β-estimate −0.021, 95% CI −0.030 to −0.013, p<0.001) and a higher global wasted work (GWW) (r=0.280, p=0.017) were associated with a higher burden of perfusion defects (Figure 1).

GWI showed a higher correlation with perfusion defects in oHCM P (r=−0.518, p=0.019) vs. nHCM P (r=−0.492, p<0.001), and the same was also found with GWE (oHCM: r=−0.591, p=0.006 vs. nHCM: r=−0.317, p=0.022) (Figure 2A). Furthermore, GCW showed a slightly higher correlation with hypoperfusion in oHCM P (r=−0.564, p=0.010) vs. nHCM P (r=−0.520, p<0.001). There was no significant difference between oHCM and nHCM P regarding GWW.

In P with LGE ≥15%, GWI showed a better correlation with perfusion defects (r=−0.489, p=0.007) vs. P with LGE of <15% (r=−0.369, p=0.007). Moreover, GCW showed a higher correlation with hypoperfusion in P with LGE ≥15% (r=−0.455, p=0.013) comparing with P with LGE <15% LV mass (r=−0.359, p=0.019) (Figure 2B). No difference was found regarding GWE and GWW according to LGE burden.

Conclusion

In our cohort of P with HCM, impaired GWI, GWE and GCW and a higher GWW were significantly correlated with the presence of myocardial ischemia in CMR. This correlation was greater in P with oHCM and in P with LGE of ≥15% of LV mass.

Funding Acknowledgement

Type of funding sources: None.

Impact of coronavirus disease 2019 on adult patients with congenital heart disease

Background

COVID-19 is responsible for a worldwide pandemic, causing more than 18,000 deaths to date in Portugal. Data already exists regarding the increased risk of adverse events in patients with cardiovascular diseases, however the impact of SARS-CoV-2 infection in patients (P) with congenital heart disease (CHD) is still under investigation.

Purpose

To study the impact of COVID-19 in a adult patients with CHD

Methods

Adult patients seen at the CHD outpatient's clinic at a tertiary centre, who became infected with SARS-CoV-2 infection up to December 2021 were included. Assessment of patients' symptoms, need for hospitalization and admission in an intensive care unit was assessed based on medical records.

Results

We identified seventy-nine patients (pts) with COVID-19 infection. Symptoms were present in 67 (84%). The median age was 44 (15) years, 52% were females. Eight P (10%) had complex cyanotic disease; seven Tetralogy of Fallot; five (6%) transposition of great arteries; eight (10%) right ventricle obstacle; two (3%) atrioventricular canal defect; sixteen (20%) atrial septal defect; nine (11%) ventricular septal defect; eight (10%) aortic coarctation; two (3%) had Eisenmenger syndrome. 49% of P had previous surgery or percutaneous procedure. 63% of P were at New York Heart Association (NYHA) class of I and 30% at NYHA II. Mild symptoms were reported by 56 P (71%). Ten adults (7,9%) experienced moderate symptoms (dyspnea and hypoxia) that led to hospitalization for oxygen therapy, none required mechanical ventilation. One death was reported in an 83-year-old patient with non-corrected interventricular communication and compromised biventricular function. There was a significant association between the gravity of CHD and hospitalizations (p=0.02).

Conclusion

Our pts had mainly mild to moderate symptoms and did not appear to have a disproportionately negative outcome; the need for hospitalization was more frequent in patients with higher CHD gravity. These findings are in line with the emerging data regarding COVID-19 in CHD P, and may be in part explained by the patient's young age and functional status.

Funding Acknowledgement

Type of funding sources: None.

Cardiac myxomas: characteristics and outcomes in a tertiary center

Introduction

Cardiac myxoma (CM) is the most common primary cardiac tumour. It can manifest in a variety of clinical presentations or it can be asymptomatic and, ultimately, be detected with image techniques. The only successful treatment of these tumours is surgical excision, with low complications and recurrence rate.

Objectives

This analysis aims to describe the clinical forms of presentation and echocardiographic characteristics of cardiac myxomas, establish myxoma features associated with obstructive symptons, as well as describe the postoperative outcome and long-term recurrence in a tertiary center.

Methods

Between 1990 and 2021, 88 patients were diagnosed with cardiac myxoma. 84 were included in this analysis. Baseline characteristics, clinical presentation, echocardiographic findings and outcomes were noted retrospectively. A binary logistic regression analysis using SPSS statistics software, version 25.0 was performed to establish myxoma features associated with atrioventricular valves obstruction.

Results

Mean age was 63±12 years old, 75% female. All CM were sporadic. The majority of the patients (52.4%, n=44) were asymptomatic, embolic events were present in 22.9% of the patients (n=19), with the most common site being central nervous system (19.0%, n=16) and constitutional symptoms in 16.7% (n=14), the most frequent fatigue (11.9%, n=10). Atrial fibrilation was present in 9.6% of the patients (n=8). The majority of the myxomas were located in the left atrium (88.1%), followed by right atrium (10.7%) and right ventricle (1.2%). Mean myxoma dimension was 36.8±17.4mm (longer axis), with heterogeneous aspect in 63.1%, presence of calcification in 11.9%, pediculated insertion in 40.5%, mobility in 70.2% and irregular borders in 52.4%. Moderate or severe ventricular inflow obstruction was present in 13.1% (n=11), 13.6% with mitral obstruction in the left atrial myxomas and 11.1% with tricuspid obstruction in the right atrial myxomas. CM longer axis 40–59mm and superior to 60mm were independently associated with obstruction (OR 5.1, 95% CI 1.4–18.4, p0.014 and OR 11.5, 95% CI 2.9–45.4, p0.001, respectively). No other morphologic features were associated with mitral or tricuspid obstruction. All but 3 patients had the myxoma surgically removed because of advanced age and comorbidities (96.4% surgical rate). There was no in-hospital or 1 year mortality in these patients. During the follow-up period, 3.6% patients had recurrence of the myxoma, with a men period of 5 years after the first surgery (one, two and twelve years), all of them re-submitted to surgical excision.

Conclusion

Despite being asymptomatic in the majority of the patients and often diagnosed incidentally, cardiac myxomas are frequent source of morbidity and mortality due to embolic events, obstructive and constitutional symptoms. Surgery is the treatment of choice for cardiac myxomas and in most cases it is curative, with low complications and low recurrence rate.

Funding Acknowledgement

Type of funding sources: None.

3 year outcomes of permanent pacemaker implantation after alcoholic septal ablation

Introduction

Patients with hypertrophic obstructive cardiomyopathy (HOCM) that remain symptomatic despite optimized medical therapy are often submitted to alcohol septal ablation (ASA). One of the most frequent complications is the complete hear block (CHB), requiring permanent pacemaker (PPM) in variable rates, up to 20% of the patients. The long-term impact of PPM implantation in these patients remains unclear.

Objectives

This study aims to evaluate the long-term clinical outcomes in patients who implant PPM after ASA.

Methods

In a tertiary center, patients who underwent ASA were consecutively enrolled prospectively. Patients with previous PPM or implantable cardio-defibrillator were from this analysis. The groups with and without PPM implantation after ASA were compared regarding baseline characteristics, procedure data and 3-year primary and secondary endpoints.

Results

Between 2009 and 2020, 109 patients underwent ASA. 97 patients were included in this analysis (68% female, mean age 65.2 years-old). 16 patients (16.5%) required PPM implantation for CHB. In those, no vascular access, pacemaker pocket or pulmonary parenchyma complications were noted. The baseline characteristics regarding comorbidities, symptoms, echocardiographic and electrocardiographic findings were identical in the two groups, with statistically significant differences in the mean age (70.6y/o in the PPM group versus 64.1y/o) and in the beta-blocker therapy rates previously to the intervention (56% in the PPM group versus 84%). Procedure-related data showed higher creatine kinase (CK) peaks in the PPM group (1692U/L versus 1243U/L, p0.05), without significant differences in the alcohol dose (2.1ml in both groups, p0.33). At 3 years after ASA procedure, the primary endpoint (composite of all-cause mortality and all-cause re-hospitalization) showed a statistical tendency to a lower event rate in the group who implanted PPM (p-value 0.097, Graphic 1). The secondary endpoint (composite of all-cause mortality and cardiac cause re-hospitalization) did not show any significant statistical difference between the two groups (p-value 0.216, Graphic 2).

Conclusions

The long-term endpoint analysis suggests that the outcomes in patients who implant PPM after ASA are non-inferior to those who do not, with a tendency to a lower rate of the endpoint composite of all-cause mortality and all cause re-hospitalizations.

Funding Acknowledgement

Type of funding sources: None.

POS1282 PEDIATRIC INFLAMMATORY MULTISYSTEM SYNDROME TEMPORALLY-ASSOCIATED WITH SARS-CoV-2 – A PORTUGUESE SINGLE CENTRE CASE SERIES

Background

Across the globe, coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 appears to affect paediatric population in a milder and nonthreatening way, when compared to adults. However, since April 2020 case reports of previously healthy children presenting with unremitting fever, biologic inflammatory syndrome and cardiac dysfunction have been emerging. This syndrome, which has been termed Pediatric Inflammatory Multisystem Syndrome Temporally Associated with SARS-CoV-2 infection (PIMS-TS), represents a rare complication of COVID-19 in children1.

Objectives

To describe the clinical, laboratory and imaging characteristics, course, management and outcomes of hospitalized children diagnosed with PIMS-TS in a Portuguese tertiary care hospital.

Methods

A retrospective study including children (< 18 years) that attended our hospital from April 2020 to December 2021 was performed. All the children included fulfilled the case definition of PIMS-TS published by the Centre for Disease Control and Prevention. Sociodemographic and clinical data, laboratory markers and imaging findings were collected.

Results

A total of 19 children met the criteria for PIMS-TS, 68% male with a mean age at diagnosis of 8 years old (IQR 5.8-15). They were all caucasian, except for a mixed-race patient, and all previously healthy, except one patient who was obese. Twelve had recent infection by SARS-CoV-2 detected by reverse transcriptase (RT) PCR and 18 had positive IgG serology.

All had fever at diagnosis, with a median duration of 6 days (IQR 5-6) and 89.5% had mucocutaneous, gastrointestinal and hematological attainment, respectively. Other affected systems were respiratory (73.7%), cardiovascular (63%), lymphoid organs (52.6%), musculoskeletal (47%), genito-urinary (31.6%) and neurological (26.3%). Laboratory findings can be found in Table 1.

Thirty-six percent were admitted in intensive care unit for a median duration of 8 days (IQR 4-9). 42.1% needed respiratory support, 87.5% with supplemental oxygen therapy, 62.5% with mechanical ventilation and 12.5% with non-invasive ventilation. All patients received intravenous (IV) immunoglobulin, 52.6% IV corticosteroid (CS) pulses and 78.9% IV and oral CS. Other treatments included acetylsalicylic acid (n=18), heparin (n=8) and antibiotic therapy (n=19) - Table 3. Seventeen fully recovered and 2 had sequalae: one of them with coronary artery aneurysms and other exertional dyspnea.

Conclusion

In this case series, there was a broad spectrum of clinical symptoms and disease severity, ranging from fever and systemic inflammation to critical care admission with myocardial injury, shock, and development of coronary artery aneurysms.

Despite short-term morbidity, there were no mortality cases, with most of them recovering without sequelae. All physicians providing clinical care to children should consider this rare but severe delayed syndrome in paediatric population.

References

[1]Ramcharan T, Nolan O, Lai CY et al. Paediatric Inflammatory Multisystem Syndrome: Temporally Associated with SARS-CoV-2 (PIMS-TS): Cardiac Features, Management and Short-Term Outcomes at a UK Tertiary Paediatric Hospital. Pediatr Cardiol. 2020 Oct;41(7):1391-1401.

Characters from table content including title and footnotes: 710

Disclosure of Interests

None declared

Permanent pacemaker implantation after Alcoholic Septal Ablation: long-term outcomes

Funding Acknowledgements

Type of funding sources: None.

Introduction

Patients with hypertrophic obstructive cardiomyopathy (HOCM) that remain symptomatic despite optimized medical therapy are often submitted to alcohol septal ablation (ASA). One of the most frequent complications is the complete heart block (CHB), requiring permanent pacemaker (PPM) in variable rates, up to 20% of the patients. The long-term impact of PPM implantation in these patients remains unclear.

Objectives

This study aims to evaluate the long-term pacemaker dependency in patients with PPM after ASA and to assess the long-term impact of PPM in these patients.

Methods

In a tertiary center, patients who underwent ASA were retrospectively analyzed. Patients with previous PPM or implantable cardio-defibrillator were excluded. The groups with and without PPM implantation after ASA were compared regarding baseline characteristics, procedure data and outcomes. In the group who implanted PPM, the long-term pacing rates were evaluated.

Results

Between 2009 and 2020, 109 patients underwent ASA. 97 patients were included in this analysis (68% female, mean age 65.2 years-old). 16 patients (16.5%) required PPM implantation for CHB. In those, no vascular access, pacemaker pocket or pulmonary parenchyma complications were noted. The baseline characteristics regarding co-morbidities, symptoms, echocardiographic and electrocardiographic findings were identical in the two groups, with statistically significant differences in the mean age (70.6y/o in the PPM group versus 64.1y/o) and in the beta-blocker therapy rates previously to the intervention (56% in the PPM group versus 84%). Procedure-related data showed higher creatine kinase (CK) peaks in the PPM group (1692U/L versus 1243U/L, p0.05), without significant differences in the alcohol dose (2.1ml in both groups, p0.33). In the PPM group, the mean pacing rates at 1 month, 1 year and 2 years were 66.6±38.0, 50.4±44.1 and 50.8±42.5, respectively, with 2 patients (12.5%) having 1-5% pacing and none having pacing &lt;1% at 2 years. In the group without PPM, 5 patients (6.2%) required posteriorly PPM implantation during the follow-up. There were no statistically significant differences in the two groups regarding in-hospital mortality, 1 year mortality or 1 year re-hospitalization. Despite a lower mean follow-up period in the PPM group (2.3±1.5 years versus 3.5±2.2 years, p0.05), there were no differences in the groups regarding all-cause mortality, cardiac cause mortality and cardiac cause re-hospitalization, with a statistical tendency to a lower all cause re-hospitalization in the PPM group (19% versus 43%, p0.07).

Conclusions

The registered pacing rates shows that all devices were adequately implanted. The long-term impact analysis suggests that the outcomes in patients who implant PPM after ASA are non-inferior to those who do not, with a tendency to reduce all cause re-hospitalizations.

Ecocardiographic comprehensive evaluation of OHCM patients treated with percutaneous ASA

Funding Acknowledgements

Type of funding sources: None.

Introduction

Alcohol septal ablation (ASA) has been widely accepted as an alternative to surgical myectomy in patients with symptomatic obstructive hypertrophic cardiomyopathy (OHCM) despite optimal medical treatment.

The aim of this study was to analyse the effect of ASA on anatomical and functional features analysed by echocardiography, as well as its clinical impact. We further evaluated the safety of procedure.

Methods and results

Retrospective analysis of consecutive patients submitted to ASA (2009 – 2019) in a single tertiary centre. A dedicated echocardiogram was performed at 3 and 6 months after procedure. Echocardiographic primary endpoint was a &gt; 50% reduction in left ventricular outflow tract (LVOT) gradient (the definition used for successful procedure). Echocardiographic secondary endpoint was improvement in mitral regurgitation. Clinical primary endpoint was defined as a combined endpoint of cardiac death or hospitalization during follow-up (FU).

110 patients were included, 66.4% women, mean age 65.1 ± 12.2 years. Functional class NHYA class III/IV, angina CCS class II/III and syncope were present in 87.3%, 52.7% and 10.0%, respectively.

Baseline LVOT gradients at rest and at Valsalva manoeuvre were 93.6 ± 39.8 mmHg and 118.9 ± 44.2 mmHg. Maximum septal thickness was 21.0 ± 3.3 mm, 24.5% had moderate mitral regurgitation and 52.7% showed systolic anterior motion of mitral valve.

During hospitalization for ASA, peak creatine kinase after procedure was 1306 ± 816 U/l. 17 (17.1%) patients required permanent PM due to induction of permanent complete heart block. There was one case of inferior myocardial infarction and one case of cardiac tamponade. 

Echocardiographic primary endpoint was achieved by 83.6% of patients. At 3 and 6-months follow up, LVOT gradients was significantly decreased in successful comparing with unsuccessful procedure group (24.6 ± 23.9 vs 82.0 ± 28.7 mmHg, p = 0.003 and 31.8 ± 34.5 vs 68.6 ± 27.8 mmHg, p = 0.027, respectively). There was no difference in baseline clinical or echocardiographic parameters between both groups. Regarding the echocardiographic secondary endpoint, among patients with moderate mitral regurgitation, 80% improved to mild regurgitation. A significant reduction in basal septal thickness was achieved in most patients, from 21.0 ± 3.3mm to 16.4 ± 2.7 mm after ASA (p = 0.001). 

During mean FU of 3.4 ± 2.1 years, clinical primary endpoint occurred in 25.5%, mainly in unsuccessful procedure group (50.0% vs 20.7%, p = 0.013). Reintervention was performed for recurrence of symptoms in 14 (12.7%) patients, surgical myectomy in 3 (3.6%) and repeated ASA in 10 (9.1%). 

Conclusion

ASA allows a significant reduction in LVOT gradient and improvement of mitral regurgitation in the majority of patients with OHCM. Systematic and comprehensive echocardiographic evaluation assumes a paramount importance for the evaluation of procedural success. Abstract Figure.

Three dimensional myocardial deformation parameters are associated with functional capacity in hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Introduction

Three-dimensional (3D) echocardiography is an emerging tool for assessment of left ventricular function, with a promising role in the evaluation of cardiomyopathies. Hypertrophic cardiomyopathy (HCM) is often associated with reduced exercise capacity. The aim of this study was to evaluate the importance of 3D myocardial deformation parameters as predictors of exercise capacity in HCM patients (P).

Methods

This prospective study enrolled P with HCM. Each P underwent a comprehensive transthoracic echocardiogram including 3D speckle-tracking to measure global longitudinal, radial and circumferential strain, twist, torsion and global area strain. Functional capacity was objectively assessed by treadmill cardiorespiratory exercise testing.

Results

83 patients with HCM, 50 (60%) male, mean left ventricular ejection fraction (LVEF) of 68 ± 7%, 27 (33%) with obstructive HCM (LV outflow tract [LVOT] gradient of 89 ± 60 mmHg). Impairment in LV myocardial deformation parameters was significantly correlated with lower peak VO2: global longitudinal 3D strain (r=-0.397, p &lt; 0.001), global radial 3D strain (r = 0.336, p = 0.003) and global circumferential 3D strain (r=-0.353, p = 0.002) (Figure 1).

Impaired LV twist was significantly correlated with inferior peak VO2 (r = 0.264, p = 0.033) (Fig.2) and peak circulatory power (r = 0.371, p = 0.003). Torsion impairment also significantly associated with lower peak VO2 (r = 0.285, p = 0.021), circulatory power (r = 0.380, p = 0.002), time to ventilatory anaerobic threshold (VAT) (r = 0.369, p = 0.003) and (VE/VCO2 slope)/peak VO2 ratio (r=-0.316, p = 0.012).

Furthermore, global area strain impairment showed significant relation with decreased peak VO2 (r=-0.368, p = 0.001), lower exercise duration (r=-0.384, p = 0.001), time to VAT (r=-0.404, p &lt; 0.001), circulatory power (r=-0.272, p = 0.032) and (VE/VCO2 slope)/peak VO2 ratio (r = 0.391, p = 0.002). LV twist (r=-0.135, p = 0.284), torsion (r=-0.120, p = 0.341) and global area strain (r = 0.152, p = 0.235) impairment did not correlate with VE/VCO2 slope. Exercise capacity was not associated with LV mass index (r = 0.209, p = 0.095), LV end-diastolic volume (r = 0.058, p = 0.639), maximum wall thickness (r = 0.041, p = 0.744), LVEF (r=-0.092, p = 0.458), 2D global longitudinal strain (r=-0.024, p = 0.848) or peak LVOT gradient (r=-0.006, p = 0.964). In a subanalysis examining only the nonobstructive (nHCM) P, we found that peak VO2 had a superior correlation with global longitudinal 3D strain (r=-0.420, p = 0.004), global radial 3D strain (r = 0.356, p = 0.016) and global circumferential 3D strain (r=-0.357, p = 0.016) as well as LV twist (r = 0.300, p = 0.046) and torsion (r = 0.336, p = 0.024).

Conclusion

Although P with HCM often have supranormal LVEF, 3D speckle-tracking echocardiographic imaging has the potential to demonstrate subclinical impairment of LV function. Impaired LV 3D strain, twist, torsion and global area strain were associated with reduced exercise capacity, particularly in nHCM P. Abstract Figure. Peak VO2 and 3D strain parameters  Abstract Figure. LV twist, torsion and global area strain

Microvascular dysfunction and myocardial fibrosis impact on left ventricular myocardial deformation in hypertrophic cardiomyopathy: per segment analysis by magnetic resonance imaging

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular hypertrophy (LVH) and microvascular dysfunction are hallmarks of hypertrophic cardiomyopathy (HCM). We hypothesized that microvascular dysfunction contributes to LV myocardial deformation impairment.

Methods

Prospective evaluation of adult patients with HCM (patients with "end-stage" HCM, prior septal reduction therapy or epicardial coronary artery disease were excluded). All underwent a cardiac magnetic resonance (CMR) protocol (1.5-T), from which the following parameters were analysed: maximal LV wall thickness (MLVWT), T1 and T2 mapping, extracellular volume, late gadolinium enhancement (LGE) and stress perfusion. Three-dimensional strain analysis was obtained by using feature-tracking from cine images. Results were stratified according to the 16 American Heart Association segments. Multivariate regression analyses for longitudinal, circumferential and radial strain were performed.

Results

A total of 1200 myocardial segments were analysed (Table 1) (75 patients, 63% male, age 54.6 ± 14.7 years) including 61% with asymmetric septal LVH, 29% with apical LVH, 8% with concentric LVH, 28% exhibiting LV outflow tract obstruction. The mean MLVWT was 20 ± 4.5mm.

Higher values of longitudinal strain (lower deformation) were found in segments with MLVWT ≥15mm (β-estimate: 2.31, 95% CI 0.91-3.70, p &lt; 0.001) and in patients with obstructive HCM (β-estimate: 2.44, 95% CI 1.15-3.72, p &lt; 0.001]) (Table 2). No association was found between perfusion defects, LGE and longitudinal strain.

Higher values of circumferential strain (lower deformation) were found in segments with MLVWT 12-14mm (β-estimate: 2.31, 95% CI 1.36-3.25, p &lt; 0.001), MLVWT ≥15mm (β-estimate: 5.29, 95% CI 4.47-6.12, p &lt; 0.001), with perfusion defects (β-estimate: 2.75, 95% CI 2.0-3.5, p &lt; 0.001), with LGE (β-estimate: 2.49, 95% CI 1.77-3.22, p &lt; 0.001) and in patients with obstructive HCM (β-estimate: 1.25, 95% CI 0.44-2.06, p = 0.003).

Lower radial strain values were found in segments with MLVWT 12-14mm (β-estimate: -10.64, 95% CI -13.95 to -7.33, p &lt; 0.001), with MLVWT ≥15mm (β-estimate: -20.67, 95% CI -23.36 to -17.97, p &lt; 0.001), with perfusion defects (β-estimate: -10.60, 95% CI -13.08 to -8.13, p &lt; 0.001), and with LGE (β-estimate: -10.49, 95% CI  -12.86 to -8.11) (table 2).

Diabetes, hypertension and BMI &gt; 25 kg/m2 were also associated with impaired myocardial deformation. Male gender correlated with worse radial and circumferential strain values.

No association was found between parametric mapping values and LV myocardial deformation.

Conclusion

In patients with HCM, three-dimensional speckle tracking parameters for LV systolic function were particularly impaired in segments with LVH, microvascular dysfunction or fibrosis. LVH was associated with abnormal longitudinal, circumferential and radial strain while perfusion defects and LGE correlated with impaired circumferential strain and radial strain. Abstract Table 1: Characteristics of AHA segments  Abstract Table 2: Multivariate analysis

Assessment of myocardial work: a promising tool in obstructive and nonobstructive hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Introduction

Myocardial work is a novel dynamic non-invasive method for assessing myocardial deformation providing incremental information to left ventricular ejection fraction (LVEF) and strain imaging. The aim of this study was to assess left ventricular myocardial work in hypertrophic cardiomyopathy (HCM) and compare patients with obstructive HCM (oHCM) and nonobstructive HCM (nHCM).

Methods

Prospective assessment of HCM patients’ myocardial strain parameters with 2D speckle-tracking echocardiography, stratified according to LV segments (basal, midcavity and apical regions). Results were compared between oHCM and nHCM patients.

Results

83 patients with HCM, 60% male, 33% oHCM (with a LVOT gradient of 89 ± 60 mmHg). There was no significant difference between groups in mean age (56 ± 13 years vs. 55 ± 15 years, p = 0.719), LV mass index (186 ± 75 g/m2 vs. 158 ± 65 g/m2, p = 0.103), maximum wall thickness (21 ± 4 mm vs. 19 ± 5 mm, p = 0.425) or left ventricular ejection fraction (LVEF) (68 ± 8% vs. 67 ± 11%, p = 0.584).

Regarding global work index (GWI) there was no significant difference between oHCM and nHCM (1206 ± 431 mmHg% vs. 1384 ± 437 mmHg%, p = 0.090), although oHCM patients had a significantly inferior GWI in the basal (921 ± 383 mmHg% vs. 1364 ± 419 mmHg%, p &lt; 0.001) and midcavity (1049 ± 456 mmHg% vs. 1288 ± 492 mmHg%, p = 0.038) segments (Figure 1). No significant difference was noted in the apical segments (1680 ± 653 mmHg% vs. 1519 ± 770 mmHg%, p = 0.335). Myocardial work index in the basal segments showed inverse correlation with resting LVOT gradient (r=-0.242, p = 0.032) and maximum provoked LVOT gradient (r=-0.291, p = 0.010). Furthermore, patients with septal hypertrophy pattern showed significantly impaired basal myocardial work index compared with apical hypertrophy patients (1090 ± 428 mmHg% vs 1537 ± 389 mmHg%, p &lt; 0.001).

Global constructive work (GCW) (1443 ± 449 mmHg% vs. 1604 ± 426 mmHg%, p = 0.123) and global wasted work (GWW) (197 ± 140 mmHg% vs. 154 ± 107 mmHg%, p = 0.137) were not significantly different between groups.

Global work efficiency (GWE) was significantly reduced in oHCM patients vs. nHCM (84.1 ± 7% vs. 88.3 ± 7.3%, p = 0.017), particularly in the basal (80.2 ± 11.2% vs. 88.3±.7.2%, p = 0.033) and midcavity segments (85.4 ± 9.2% vs. 90.0 ± 8.5%, p = 0.044) (Figure 2). No significant difference was noted in the apical segments (88.2 ± 9.9% vs. 87.0 ± 12%, p = 0.679). Myocardial work efficiency in the basal segments showed inverse correlation with resting LVOT gradient (r=-0.389, p = 0.002) and maximum provoked LVOT gradient (r=-0.446, p &lt; 0.001). Moreover, patients with septal hypertrophy pattern showed significantly reduced basal myocardial work efficiency versus apical hypertrophy patients (83 ± 9% vs 92 ± 3%, p &lt; 0.001).

Conclusion

Myocardial work is a promising tool to evaluate myocardial function in patients with oHCM and nHCM. oHCM patients had a significantly inferior GWI and GWE particularly in the basal and midcavity segments versus nHCM patients. Abstract Figure 1: Myocardial Work Index  Abstract Figure 2: Myocardial Work Efficiency

Three-dimensional myocardial deformation parameters are associated with functional capacity assessed by cardiopulmonary exercise testing in patients with hypertrophic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Introduction

Myocardial deformation parameters, derived from three-dimensional (3D) speckle-tracking echocardiography (3DSTE) are useful tools to determine left ventricular (LV) systolic function, and are often abnormal before a decline in ejection fraction (EF).

Aims

To study the correlation between systolic function evaluated by myocardial deformation parameters obtained by 3DSTE and functional capacity in patients with HCM.

Methods

HCM patients seen prospectively at outpatient cardiomyopathy clinic at a tertiary centre were included. Systolic function was assessed by strain measures – global longitudinal, circumferential and radial strain - obtain by 3DSTE, LVEF by 2D and 3D echocardiography were also assessed.  Functional capacity was evaluated by CPET.

Results

Of 67 P with HCM (mean age 57 ± 14 years, 41 males), 38 P (56.7%) were in New York Heart Association (NYHA) functional class I, 24 (35.8%) in class II and 5 (7.5%) in class III. 46P (68.7%) had obstructive (HCM), with a maximum LV wall thickness (MWT) of 20 (7) mm. 3DSTE and CPET parameters are reported in Table 1.

Absolute values of 3D global radial strain showed correlation with pVO2 (r=-0.336, p = 0.006), as well as longitudinal strain (r=-0.280, p= 0.024). No association was found between LVEF and pVO2. MWT did not correlate with 3DSTE strain measures.

Conclusion

Impaired myocardial deformation was associated with worse functional capacity assessed by peak oxygen consumption.

Segmental analysis of microvascular dysfunction and tissue characterization in hypertrophic cardiomyopathy by magnetic resonance imaging

Funding Acknowledgements

Type of funding sources: None.

Background

While left ventricular hypertrophy (LVH) and myocardial fibrosis are frequently evaluated in hypertrophic cardiomyopathy (HCM), microvascular dysfunction is often overlooked. The aim of this study was to assess the association between wall thickness, microvascular dysfunction and tissue characteristics in HCM patients (P), comparing individual myocardial segments.

Methods

Prospective evaluation of adult P with HCM (P with "end-stage" HCM, prior septal reduction therapy or epicardial coronary artery disease were excluded). All underwent a cardiac magnetic resonance (CMR) protocol (1.5-T), from which the following parameters were analysed: maximal LV wall thickness (MLVWT), T1 and T2 mapping, extracellular volume (ECV), late gadolinium enhancement (LGE) and stress perfusion. Results were stratified according to the 16 American Heart Association segments. Multivariate regression analyses for perfusion defects and tissue characteristics were performed.

Results

75 P (total of 1200 myocardial segments analysed), 63% male, mean age 55 ± 15 years, MLVWT of 20 ± 4.5mm (61% asymmetric septal LVH, 29% apical LVH and 8% concentric LVH). 28% presented LV outflow tract obstruction.

MLVWT was greater in the basal and mid septum (table 1). Among the 424 segments (35.3%) with a perfusion defect, 286 (23.8%) had a defect only in the endocardial layer and 138 (11.5%) in both endocardial and epicardial layers with defects more often detected in hypertrophied segments. This association was verified in segments with MLVWT 12-14mm and MLVWT ≥15mm (OR 7.83, 95% CI 5.75-10.67, p &lt; 0.001) (table 2). Among the 660 segments with normal MLVWT (≤11mm), 123 (19%) presented perfusion defects. A perfusion defect was more frequent in segments of obstructive HCM P (OR 1.48, 95% CI 1.13-1.92, p = 0.004).

Microvascular dysfunction was associated with changes in tissue characteristics. For the same thickness, segments with perfusion defects had a higher T1 mapping (β-estimate 20.91, 95% CI 16.87-24.96, p &lt; 0.001) and T2 mapping mean values than those without. Furthermore, regardless of MLVWT, segments with perfusion defects had LGE more often (OR 4.16, 95% CI 3.19-5.41, p &lt; 0.001) and a higher ECV. On the other hand, among the 424 segments with a perfusion defect, 115 (27%) did not present LGE.

MLVWT was associated with tissue characteristics. Comparing to non-hypertrophied segments, T1 mapping mean value was higher in segments with MLVWT 12-14mm and with ≥15mm (β-estimate 37.71, 95% CI 31.2-44.21, p &lt; 0.001). Segments with MLVWT ≥15mm showed a significantly superior ECV mean value comparing to non-hypertrophied segments. LGE was more frequent in the more hypertrophied segments: MLVWT 12-14mm and ≥15mm (OR 9.02, 95% CI 6.42-12.67, p &lt; 0.001) (Table 2).

Conclusion

Microvascular dysfunction is more prevalent in obstructive HCM, particularly in the more hypertrophied segments. The presence of microvascular dysfunction is associated with diffuse tissue abnormalities and replacement fibrosis. Abstract Table 1: Characteristics of AHA segments  Abstract Table 2: Multivariable analyses

Quantification of epicardial fat with cardiac CT and association with cardiovascular risk factors and obstructive coronary disease

Introduction

Recent studies advocate epicardial fat (EF) as a biologically active organ that influence coronary atherosclerosis development through endocrine and paracrine pathways. We aim to study the relations between EF, thoracic adipose tissue (TAT), cardiovascular risk factors (CRF) and obstructive coronary disease (OCD).

Methods

Retrospective analysis of patients (pts) referred to 64-multislice cardiac computed tomography (CT) in one center. The authors underwent a standardized protocol for quantification of EAT, TAT (subcutaneous and visceral), abdominal visceral fat, coronary calcium score and angiography.

Results

Total of 178 pts: male 99 (56%), mean age 65.9±12.9 years. Indications for performing CT were coronary disease (76%), valvular heart disease (15%), atrial fibrillation (6%) and congenital heart disease (2%). Regarding CRF, EF was only significant higher in patients with diabetes (115±60 vs 95±47, p=0.018), in male gender (114±60 vs 91±42, p=0.04) and was linear correlated with age (p=0.004). The authors also found that EF volume is significant higher in patients with typical angina (p=0.02) and with coronary atherosclerosis: non-obstructive (p=0.0049) and OCD (p=0.001) – Graphic 1. ROC analysis of EF (AUC 0.659, p=0.0039) and EF/TAT relation (AUC 0.704, p=0.003) allowed to estimate that EF&gt;100 ml and EF/TAT &gt;0.06 had a sensibility to predict OCD of 53% and 58%, respectively, and specificity of 66% and 60%. We did not find a correlation between EF, EF/TAT or TAT and coronary calcium score.

Conclusion

EF is higher in patients with diabetes and coronary atherosclerosis. EF and EF/TAT relation had moderate sensibility and specificity to predict OCD, irrespective of calcium score. EF and EF/TAT are promising atherosclerotic markers that could be routinely use in the near future.

Funding Acknowledgement

Type of funding sources: None.

A 3D-TTE left atrial function study in cardio-oncology patients

Introduction

Transthoracic Doppler echocardiography (TTE) remains the standard imaging method to evaluate cancer therapeutics-related cardiac dysfunction (CTRCD). 3D-TTE with strain analysis is a novel technique, proved useful for earlier detection of left ventricular (LV) function impairment. However, diastolic and left atrial (LA) function impact is less studied.

Purpose

To assess LA volumetric and LA strain (LAS) features by 3D-TTE in cardio-oncology patients.

Methods

A prospective study of female breast cancer patients (P) submitted to therapy (TH) who underwent serial monitoring by 2D and 3D-TTE. Standard 2D, 3D-TTE and LAS parameters were evaluated, including longitudinal (LALS) and circumferential strain (LACS) during conduit (cd), contraction (ct) and reservoir (r) phases. P were evaluated at T0, T1 and T2 (before, ≥6 and ≥12 months after starting TH). CTRCD was defined as an absolute decrease in 2D LVEF &gt;10% to a value &lt;54% or a relative decrease in 2D GLS &gt;15%, according to literature. P with previous cancer treatment, coronary artery disease, significant valvular disease, and atrial arrhythmias were excluded.

Results

98 P (mean age 54.6±12.0 years-old), mostly treated with anthracyclines (78.6%, cumulative dose 268.2±77.6mg/m2), anti-HER (70.4%) and radiotherapy (80.6%) were included. 2D LV and LA volumes had a significantly raise from baseline to T1 (2D LVEDV 82.2±18.8 vs 91.9±18.8 mL, p=0.019 and LA 43.3±12.9 vs 49.8±13.3 mL, p=0.005). 2D and 3D LVEF were significantly reduced during TH, however remaining within the limits of normality. 2D GLS was also impaired at T1 (−19.9±2.6% vs −18.6±3.1%, p=0.009). During a mean follow-up of 14.1±8.1months, 31 P (31.6%) developed CTRCD. 3D LV and LA volumes also globally increased at T1 comparing to baseline with partially recovery at T2. Maximum LA volume was significantly higher at T1 (39.1±9.3 vs 43.6±10.6 ml, p=0.024). 3D LA ejection fraction (T0 53.7±9.7%, T1 53.4±8.6%, T2 49.9±8.6%, pT0-T2=0.039) and LAS values tended to progressively worse during TH. LA dilation (vol&gt;34ml/m2) at baseline was correlated to dysfunction in contraction phase at T1 (LACSct −19.6±8.6 vs −17.3±4.6%, p=0.024). LACSr has substantially decreased from baseline to T2 (31.4±11.6 vs 27.0±10.4%, p=0.05). In univariate analysis, delta LALSr (T1-T0) was a predictor of CTRCD (mean −5.2% vs 1.9%, p=0.05).

Conclusion

CTRCD was frequent during the earlier phase of breast cancer treatment. LA function was also affected, mirroring LV volumetric and functional changes. Diastolic dysfunction, assessed through LA reservoir strain, was impaired in association with CTRCD. 3D-TTE usefulness in the surveillance and monitoring of CTRCD goes beyond systolic LV function assessment, allowing a detailed LA function analysis.

Funding Acknowledgement

Type of funding sources: None.

Familial hypercholesterolemia in acute coronary syndrome patients: underdiagnosis in female and in young patients

Introduction

Familial hypercholesterolemia (FH) is often underdiagnosed, particularly in female patients (P), even during hospital admission for acute coronary syndromes (ACS). The aim of this study was to apply the Dutch Lipid Clinic Network (DLCN) Criteria in P admitted for ACS and evaluate gender and age differences.

Methods

Prospective evaluation of P with ACS admitted to a tertiary center from 2005 to 2019. Data including family history and laboratory tests was analysed for the application of the DLCN criteria and results were stratified according to ACS subtype, gender and age groups (20–39, 40–59, 60–79 and ≥80 years [y]). P were followed up for 30 days for hospitalization, recurring ACS and mortality.

Results

3811 P were evaluated, mean age 63±13 years, 28% female and mean LDL cholesterol of 125±43 mg/dL. The admission diagnosis was unstable angina (UA) in 5%, non-ST-segment elevation myocardial infarction (NSTEMI) in 27% and ST-segment elevation MI (STEMI) in 68%.

Applying the DLCN criteria, 3089 P (81%) had a score of &lt;3 (unlikely FH), 675P (17.7%) a score of 3 to 5 (possible FH), 41P (1.1%) a score of 6 to 8 (probable FH) and 1P (0.03%) a score of &gt;8 (definite FH). Stratifying according to ACS type: among UA, 31P (16%) had possible FH and 4P (2.1%) had probable FH. Among NSTEMI, 145P (14.2%) had possible FH, 9P (0.9%) probable FH and 1P (0.03%) definite FH. Finally, among STEMI P, 497P (19.1%) had possible FH and 28P (1.1%) probable FH. Regarding female P, 158P (14.7%) had possible FH and 16 P (1.5%) probable FH. Among male P, 517P (18.9%) had possible FH and 25P (0.9%) probable FH (p=0.016 for interaction).

According to age groups, among P aged 20–39 y (136P), 61P (44.9%) had possible FH and 6P (4.4%) had probable FH. Concerning P aged 40–59 y (1766P), 575P (32.6%) had possible FH, 31 P (1.8%) probable FH and 1P (0.1%) definite FH. With regard to P aged 60–80 y (2122P), 80P (3.8%) had possible FH and 4P (0.2%) probable FH. Among P aged ≥80 y (1837P), only 9P (0.5%) had possible FH and no P had probable FH.

In a 30-day follow-up, there was an hospitalization rate of 3.5% (134P) and recurring ACS in 1.7% (65P), while the all-cause mortality was 2% (78P) and cardiovascular (CV) death was 1.3% (49P). Female P had a significantly lower hospitalization rate (1.8% vs 3.2%, p=0.003) as well as fewer recurring ACS (0.6% vs 1.7%, p=0.001). There was no significant gender difference regarding all-cause mortality (female 1.7% vs 1.5%, p=0.552) or CV death (0.8% vs 1.1%, p=0.323). The DLCN criteria score was significantly correlated with admission for recurring ACS (OR 1.19 [95% CI 1.04–1.36], p=0.04).

Conclusion

Application of the DLCN criteria in female P admitted for ACS revealed 158P (14.7%) with possible FH and 16P (1.5%) with probable FH. Regarding younger ACS P (20–39y), 44.9% had criteria for possible FH and 4.4% for probable FH, prompting us to do not overlook these P subgroups in daily practice and routinely assess the likelihood of FH.

Funding Acknowledgement

Type of funding sources: None.

Transesophageal echocardiography versus intracardiac echocardiography-guided left atrial appendage occlusion: a comparative analysis

Introduction

The left atrial appendage occlusion (LAAO) procedure is a therapeutic option for stroke prevention in patients with atrial fibrillation (AF) which have contraindication to oral anticoagulants or still develop embolic events despite therapeutic anticoagulation. Transesophageal echocardiography (TEE) has been the gold standard to guide this procedure, with the intracardiac echocardiography (ICE) emerging as an alternative because of the advantage of reducing the general anesthesia burden compared to TEE.

Objectives

This study aims to compare the safety, procedure-related parameters and outcomes between TEE-guided LAAO and ICE-guided LAAO.

Methods

In a tertiary center, patients who underwent TEE-guided LAAO and ICE-guided LAAO were compared retrospectively regarding technical success, procedure-related events, procedure-related parameters (fluoroscopy time, dose of radiation and contrast volume), 45 days-transthoracic echocardiography (TTE) and 1-year outcomes (mortality, stroke and major bleeding).

Results

88 patients underwent LAAO between 2009 and 2020 (n=43 with TEE, n=45 with ICE). Baseline characteristics were similar. Success was achieved in 95.3% (n=41) and 95.6% (n=43) of the patients in the TEE and ICE groups, respectively (OR 0.95, p=0.96). Procedure-related complications (major vascular complications, perforation, device embolization) didn't show significant differences (14.0% vs 8.9%, OR 1.66, p=0.46) in the TEE and ICE groups, respectively. Fluoroscopy time was inferior in the TEE group (29.1±13.6 vs 44.1±17.4 minutes, p=0.001), while radiation dose (2761±1555 vs 3397±2118 mGy, p=0.113) and contrast volume (220.3±104.1 vs 204.0±100.9mL, p=0.469) showed no significant differences. 45 days-TTE showed no significant differences between the TEE and ICE groups regarding peri-device leaks (14.0% vs 24.4%, p=0.212), device thrombus (2.3% vs 0%, p=0.990) and iatrogenic atrial septal defects, all mild (4.7% vs 13.3%, p=0.174). 1-year outcomes showed no significant differences regarding stroke (9.3% vs 4.4%, p=0.186), major bleeding (9.3% vs 2.2%, p=0.78) and all-cause mortality (9.3% vs 11.1%, p=0.38) between the TEE and ICE groups, respectively.

Conclusions

ICE-guided LAAO is associated with similar results, procedure-related events, procedure related-parameters (fluoroscopy time being the only exception) and 1-year outcomes, compared with TEE-guided LAAO.

Funding Acknowledgement

Type of funding sources: None.

Feasibility of virtual fractional flow reserve derived from coronary angiography and its correlation with invasive functional assessment

Introduction

Invasive functional assessment (iFA) of coronary artery disease (CAD) needs expensive devices, has potential procedure-related complications and is still underutilized. Virtual Fractional Flow Reserve (vFFR) derived from invasive coronary angiography (ICA) has the potential to overcome these limitations.

Purpose

To investigate the feasibility of vFFR analysis and its correlation with iFA (iFR, RFR or FFR).

Methods

Retrospective analysis of consecutive patients (pts) who underwent iFA in a tertiary center between 2019 and 2020. vFFR was calculated using a dedicated software (CAAS Workstation 8.4) based on standard non-hyperaemic coronary angiograms acquired in ≥2 different projections, by operators blinded to iFA results. Diagnostic performance and accuracy of vFFR were evaluated. vFFR was considered positive when &lt;0.80. FFR &lt;0.8 and iFR/RFR &lt;0.90 were classified as positive according to current clinical standards.

Results

Out of 113 coronary arteries of 102 pts, vFFR was successfully analysed in 106 (94%). Reasons for vFFR analysis failure were: vessel projection overlap (48%), &lt;2 angiographic projections (28%) and table movement while acquisition (24%). From 106 coronary arteries of 95 pts with analysable vFFR (78% male, mean age 67.8±9.7 years), 90 (85%) showed agreement with the respective iFA result. The vFFR predicted which lesions were physiologically significant and which were not with accuracy, sensitivity, specificity, positive and negative predictive values of 73%, 73%, 83%, 53%, and 92% respectively. The mean difference between vFFR and iFA were −0.0484±0.096 and Pearson's correlation coefficient was 0.533 (p&lt;0.001). The ROC area under the curve was 0.839 (0.751–0.928, p&lt;0.001).

Conclusion

FFR were feasible in 94% of cases analysed retrospectively. As compared to gold-standard iFA, vFFR had an overall moderate accuracy in detecting ischemia-producing lesions and a negative predictive value &gt;90%. vFFR has the potential to substantially simplify physiological coronary lesion assessment and thus improve its current uptake.

Funding Acknowledgement

Type of funding sources: None. Bland-Altman plot between vFFR and IFA

Impact of COVID-19 in adult patients with congenital heart disease

Background

COVID-19 is responsible for a worldwide pandemic, causing more than 13 000 deaths to date in Portugal. Data already exists regarding the increased risk of adverse events in patients with cardiovascular diseases, however the impact of SARS-CoV-2 infection in patients (P) with congenital heart disease (CHD) is still under investigation.

Aims

To evaluate the impact of COVID-19 in adult patients with congenital heart disease in our tertiary centre

Methods

Adult patients seen at the CHD outpatient's clinic at a tertiary centre, who became infected with SARS-CoV-2 infection up to February 2021 were included. Assessment of patients' symptoms, need for hospitalization and admission in an intensive care unit was assessed based on medical records.

Results

We identified 36 patients (pts) with COVID-19 infection. Symptoms were present in 31 (86%). The median age was 39 (32–49) years, 58% were females. Seven P (19%) had complex cyanotic disease; three (8%) Tetralogy of Fallot; three (8%) transposition of great arteries (one after Senning procedure and 2 after arterial switch); six (14%) right ventricle obstacle; two (8%) atrioventricular canal defect; four (11%) atrial septal defect; five (14%) ventricular septal defect; five (14%) aortic coarctation; two aortopathies (one submitted do David procedure); one subaortic stenosis; two (6%) had Eisenmenger syndrome. The majority (61%) of P had previous surgery and 58% were at New York Heart Association class of I. Mild symptoms were reported by 24 P (67%). Seven adults experienced moderate symptoms (dyspnea and hypoxia) that led to hospitalization for oxygen therapy, although none required mechanical ventilation. One death was reported. There was a significant association between the gravity of CHD and hospitalizations (p=0.012).

Conclusion

Our pts had mainly mild to moderate symptoms and did not appear to have a disproportionately negative outcome; the need for hospitalization was more frequent in patients with higher CHD gravity. These findings are in line with the emerging data regarding COVID-19 in CHD P, and may be in part explained by the patient's young age and functional status.

Funding Acknowledgement

Type of funding sources: None.

Exercise end-tidal carbon dioxide pressure: a new prognostic marker after acute myocardial infarction?

Funding Acknowledgements

Type of funding sources: None.

Background

Although several cardiopulmonary exercise testing (CPET) parameters have already proved to predict prognosis, there is increasing interest in finding variables that do not require maximal effort. End-tidal carbon dioxide pressure (PETCO2), an indirect indicator of cardiac output, is one of such variables. Studies in heart failure populations already suggest its role as a prognostic factor. However, data concerning other populations are still scarce.

Purpose

To assess the association between exercise PETCO2, cardiac biomarkers and systolic function following acute myocardial infarction (AMI) and to evaluate its potential prognostic role in this population.

Methods

A retrospective single-centre analysis was conducted including patients who underwent symptom-limited CPET early after AMI. We assessed PETCO2 at baseline (PETCO2-B), at anaerobic threshold (PETCO2-AT) and at peak exercise and calculated the difference between PETCO2-AT and PETCO2-B (PETCO2-difference). We analysed their association with B-natriuretic peptide (BNP), maximal troponin after AMI as well as with left ventricular ejection fraction (LVEF) 1 year after.

Results

We included 40 patients with a mean age of 56 years (87.5% male), assessed with CPET a median of 3 months after AMI (80% of which were ST-elevation myocardial infarctions). Average respiratory exchange ratio was 1,1 with 48% of patients not reaching maximal effort. Mean PETCO2-AT was 37mmHg, with a mean increase from baseline of 6mmHg (PETCO2-difference). There was a significant positive correlation between all the PETCO2 variables measured and BNP values at time of AMI and on follow-up (best correlation for PETCO2-AT with BNP at AMI hospitalization, r = 0.608, p &lt; 0.001). Maximal troponin was not correlated with PETCO2. Both PETCO2-AT and PETCO2-difference were significantly and positively correlated with LVEF 1-year post-AMI (r = 0.421, p = 0.040 and r = 0.511, p = 0.011, respectively).

Conclusion

PETCO2-AT and PETCO2-difference are both correlated with BNP, an established prognostic marker, and with medium-term systolic function after AMI, suggesting their potential prognostic role in this population. Further studies with larger samples are required to confirm the results of this pilot study and assess PETCO2 as a definite predictor of prognosis after AMI.

Acute urticaria in children: from pediatric emergency department to allergology consultation at a central hospital

Summary

Background. Acute urticaria is a common condition in the pediatric emergency department (ED) and no data is available in Portugal. Objective. We aimed to characterize the prevalence, etiology and management of acute urticaria in children presenting at an ED of a portuguese central hospital and report the follow-up investigation when drug or food allergy was suspected.Methods. Retrospective study of clinical records from children admitted to the ED with acute urticaria during one year period. Results. 250 children were included, mean age of 7.4 ± 4.9 years (0-17 years). The most frequently suspected etiological factors were infections (22%), foods (12%), insect bites (9%) and drugs (8%), of which, upper respiratory tract infections, seafood and β-lactam antibiotics were the most frequent. In 44% of cases, the etiology of urticaria was not determined. After ED discharge, of the 50 patients with suggestive drug or food allergy, only 48% were sent to allergological workup and the allergy confirmed in 6 of them (2.4% of the 250 children). Conclusions. These data suggest that allergy is not the main trigger of acute urticaria in ED children, but when suspected, reference to an allergy department to complete allergological workup was insufficient.

Transfusion transmissible pathogens are prevalent in healthy cats eligible to become blood donors

OBJECTIVES

This study aims to determine the prevalence of subclinical infectious agents considered core pathogens for worldwide screening in healthy, client-owned, indoor cats eligible to become blood donors in Spain and Portugal.

MATERIALS AND METHODS

Blood samples of healthy, indoor, domestic cats selected to be potential blood donors were tested for feline leukaemia virus antigens, feline immunodeficiency virus antibodies and polymerase chain reactions for Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, Candidatus Mycoplasma turicensis, feline leukaemia virus provirus, Leishmania spp. and Bartonella spp. Not all donors were tested for all agents.

RESULTS

Overall, 5105 healthy indoor cats were tested and 8.1% (414/5105) had at least one subclinical infectious agent that is transmissible through blood product transfusion. 1.5% (77/5105) were positive for feline leukaemia virus antigens and 2.9% (148/5105) were positive for feline immunodeficiency virus antibodies, therefore they were excluded as donors. The overall prevalence of haemoplasmas in feline leukaemia virus and feline immunodeficiency virus SNAP-negative feline blood donors was 3.7% (181/4880) [1.3% (63/4880) were positive for Mycoplasma haemofelis; 2.3% (112/4880) to Candidatus Mycoplasma haemominutum and 0.12% (6/4880) to Candidatus Mycoplasma turicensis]. The prevalence of feline leukaemia provirus was 5.2% (9/173) and of Bartonella spp. was 0.2% (2/1122). None of the 173 cats were positive for Leishmania spp.

CLINICAL SIGNIFICANCE

The prevalence of many transfusion transmissible pathogens was relatively high in this healthy, client-owned, indoor cats eligible to become blood donors. Performing an extended screening panel that includes at least polymerase chain reactions for Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, Candidatus Mycoplasma turicensis, feline leukaemia virus provirus, and Bartonella spp., in addition to feline leukaemia virus antigens and feline immunodeficiency virus antibodies, is recommended in pet blood banks from analogous regions.

Pregnancy outcomes in women with mechanical heart valves

Background

Mechanical heart valves (MHV) and their absolute need for adequate anticoagulation poses a challenge for pregnancy, either due to warfarin fetotoxicity or an increased risk of maternal thromboembolism. This represents a unique patient (P) group where data is scarce and maternal and fetal risks and benefits must be carefully weighed.

Purpose

To assess maternal and perinatal outcomes in women with MHV on different anticoagulant regimens and compare them with patients with other types of valvular heart disease (VHD).

Methods

A retrospective analysis of 131 pregnancies in 83 women with VHD (mean age 26.5±5.6 years) was carried out in a tertiary referral centre from 2000 to 2019. 92 pregnancies with VHD, including 11 with biological prosthetic valves, and 39 pregnancies in 22 P with MHV were identified. The main outcome measures were major maternal complications and perinatal outcome.

Results

MHV implanted were in mitral position (89.7%), aortic (2.6%), or both (7.7%). History of rheumatic heart disease was identified in 16 P (72.7%) and a congenital etiology was present in 2 P (9.1%). 9 P (40.9%) were on warfarine and 13 P (59.1%) on acenocumarol. Regarding anticoagulation strategy, 21 P (65.6%) remained on oral anticoagulation and 10 P (31.3%) had been switched to some form of heparin during part or the entire pregnancy. Mechanical valve thrombosis complicated pregnancy in 4 patients (10.2%), all cases on heparin, and resulted in maternal death in 1 P. MHV P had more hemorrhagic complications (15.4 vs 2.2%, p=0.004) requiring transfusion or surgical revision. MHV P tended to experience more NHYA class worsening demanding initiation or intensification of cardiac medication (17.9 vs 5.4%, p=0.023). Also in the MHV group there was a higher incidence of miscarriage (46.2 vs 12.0%, p≤0.0005), comprising spontaneous abortion (31.6 vs 7.6%, p&lt;0.0005) and fetal malformations (18.4 vs 5.4%, p=0.028), including warfarin embryopathy (10.3 vs 1.1%, p=0.012). The live birth rate was higher in women on heparin compared with those on warfarin (85.9 vs 79.2%, p=0.002). The presence of multivalve disease (p=0.04), mechanical protheses (p&lt;0.001), ACO (p&lt;0.001) and previous impaired LVEF (p=0.02) were related to miscarriage. In multivariate analysis, ACO was the unique independent predictor of unsuccessful pregnancy (p=0.01). Only 29% of the patients with an MHV had a pregnancy free of serious adverse events compared with other types of VHD (81.5%, p&lt;0.0005).

Conclusions

MHV remains a challenging condition for pregnancy with only 29% chance of experiencing an uncomplicated pregnancy with a live birth. The increased morbimortality warrant extensive prepregnancy counseling with prosthesis type discussion,centralization of care and further larger studies to come up with evidence-based recommendations.

Funding Acknowledgement

Type of funding source: None

External validation of a heart failure risk prediction model in a remote monitoring cohort submitted to cardiac resynchronization therapy

Background

Patients (P) submitted to cardiac ressynchronization therapy (CRT) are at high risk of heart failure (HF) events during follow-up. Continuous analysis of various physiological parameters, as reported by remote monitoring (RM), can contribute to point out incident HF admissions. Tailored evaluation, including multi-parameter modelling, may further increase the accuracy of such algorithms.

Purpose

Independent external validation of a commercially available algorithm (“Heart Failure Risk Status” HFRS, Medtronic, MN USA) in a cohort submitted to CRT implantation in a tertiary center.

Methods

Consecutive P submitted to CRT implantation between January 2013 and September 2019 who had regular RM transmissions were included. The HFRS algorithm includes OptiVol (Medtronic Plc., MN, USA), patient activity, night heart rate (NHR), heart rate variability (HRV), percentage of CRT pacing, atrial tachycardia/atrial fibrillation (AT/AF) burden, ventricular rate during AT/AF (VRAF), and detected arrhythmia episodes/therapy delivered. P were classified as low, medium or high risk. Hospital admissions were systematically assessed by use of a national database (“Plataforma de Dados de Saúde”). Accuracy of the HFRS algorithm was evaluated by random effects logistic regression for the outcome of unplanned hospital admission for HF in the 30 days following each transmission episode.

Results

1108 transmissions of 35 CRT P, corresponding to 94 patient-years were assessed. Mean follow-up was 2.7 yrs. At implant, age was 67.6±9.8 yrs, left ventricular ejection fraction 28±7.8%, BNP 156.6±292.8 and NYHA class &gt;II in 46% of the P. Hospital admissions for HF were observed within 30 days in 9 transmissions. Stepwise increase in HFRS was significantly associated with higher risk of HF admission (odds ratio 12.7, CI 3.2–51.5). HFRS had good discrimination for HF events with receiving-operator curve AUC 0.812.

Conclusions

HFRS was significantly associated with incident HF admissions in a high-risk cohort. Prospective use of this algorithm may help guide HF therapy in CRT recipients.

Funding Acknowledgement

Type of funding source: None

Analysis of Machine Learning Algorithms for Diagnosis of Diffuse Lung Diseases

Computational Intelligence Re-meets Medical Image Processing

A Comparison of Some Nature-Inspired Optimization Metaheuristics Applied in Biomedical Image Registration

Background Diffuse lung diseases (DLDs) are a diverse group of pulmonary disorders, characterized by inflammation of lung tissue, which may lead to permanent loss of the ability to breathe and death. Distinguishing among these diseases is challenging to physicians due their wide variety and unknown causes. Computer-aided diagnosis (CAD) is a useful approach to improve diagnostic accuracy, by combining information provided by experts with Machine Learning (ML) methods.

Objectives Exploring the potential of dimensionality reduction combined with ML methods for diagnosis of DLDs; improving the classification accuracy over state-of-the-art methods.

Methods A data set composed of 3252 regions of interest (ROIs) was used, from which 28 features were extracted per ROI. We used Principal Component Analysis, Linear Discriminant Analysis, and Stepwise Selection – Forward, Backward, and Forward-Backward to reduce feature dimensionality. The feature subsets obtained were used as input to the following ML methods: Support Vector Machine, Gaussian Mixture Model, k-Nearest Neighbor, and Deep Feedforward Neural Network. We also applied a Deep Convolutional Neural Network directly to the ROIs.

Results We achieved the maximum reduction from 28 to 5 dimensions using LDA. The best classification results were obtained by DFNN, with 99.60% of overall accuracy.

Conclusions This work contributes to the analysis and selection of features that can efficiently characterize the DLDs studied.

Resveratrol administration increases Transthyretin protein levels ameliorating AD features- importance of transthyretin tetrameric stability

Previous in vivo work showed that resveratrol has beneficial effects in the AD pathology, resulting in increased expression of transthyretin (TTR). TTR binds Aβ peptide avoiding its aggregation and toxicity, and is reduced in the CSF and plasma, in AD. Further, resveratrol binds TTR, stabilizing the native TTR tetrameric structure. To further explore the mechanism of neuroprotection conferred by TTR in AD, resveratrol was administrated, in the diet, to 5-8 months old AD transgenic female mice carrying just one copy of the mouse TTR gene, for two months. Effects in brain Aβ burden were evaluated by immunohistochemistry, and in total brain Aβ levels by ELISA, showing a striking decrease in both parameters in treated animals. In addition, total brain LRP1 protein levels were increased in treated animals, although its gene expression was unaltered. To further understand the mechanism(s) underlying such improvement in AD features, we measured TTR plasma levels showing that TTR increased in resveratrol-treated mice, whereas liver TTR gene transcription was not altered. These results strengthen the stability hypothesis, which postulates that TTR is unstable in AD leading to accelerated clearance and lower levels. Therefore, resveratrol which stabilizes the TTR tetramer results in TTR normalized clearance, thus increasing the protein plasma levels. In turn, stabilized TTR binds more strongly to Aβ peptide, avoiding its aggregation. Our results represent a step forward to the understanding of the mechanism underlying TTR protection in AD and highlight the possibility of using TTR stabilization as a therapeutic target in AD.

Nutrition transition in a middle-income country: 22-year trends in the Seychelles

BACKGROUND/OBJECTIVES

There is little objective information regarding nutrition transition in African countries. We assessed trends in nutrition patterns in the Seychelles between 1989 and 2011.

SUBJECTS/METHODS

Population-based samples were obtained in 1989, 1994 and 2011 and participants aged 25-44 are considered in this study (n=493, 599 and 471, respectively). Similar, although not identical, food frequency questionnaires (FFQs) were used in each survey and the variables were collapsed into homogenous categories for the purpose of this study.

RESULTS

Between 1989 and 2011, consumption frequency of fish (5+/week) decreased from 93 to 74%, whereas the following increased: meat (5+/week) 25 to 51%, fruits (1+/week) 48 to 94%, salty snacks (1+/week) 22 to 64% and sweet snacks (1+/week) 38 to 67% (P<0.001 for all). Consumption frequency decreased for home-brewed alcoholic drinks (1+/week) 16 to 1%, but increased for wine (1+/week) 5 to 33% (both P<0.001). Between 2004 and 2011, consumption frequency decreased for rice (2/day) 62 to 57% and tea (1+/day) 72 to 68%, increased for poultry (1+/week) 86 to 96% (all P<0.01), and did not change for vegetables (70.3 to 69.8%, P=0.65).

CONCLUSIONS

Seychelles is experiencing nutrition transition characterized by a decreased consumption frequency of traditional staple foods (fish, polished rice), beverages (tea) and of inexpensive home brews, and increased consumption frequency of meat, poultry and snacks. Food patterns also became more varied along with a broader availability of products in the 22-year interval. The health impact of these changes should be further studied.

Pollen proteases compromise the airway epithelial barrier through degradation of transmembrane adhesion proteins and lung bioactive peptides

BACKGROUND

Allergic disorders, such as seasonal rhinitis and asthma, are increasing causes of morbidity worldwide and often result from exposure to airborne pollen. Pollen allergy has a remarkable clinical impact all over Europe. In fact, epidemiological longitudinal studies confirm that pollen species usually considered with low allergenic potential became more recently responsible for intense allergic reactions. In this study, we aimed to characterize major pollen proteolytic activity and evaluate its contribution to the immunologic and inflammatory response to airborne allergens.

METHODS

Proteolytic activity in four pollen diffusates with distinct allergenicity, Olea europaea, Dactylis glomerata, Cupressus sempervirens and Pinus sylvestris, was evaluated through several enzymatic assays. The action of pollen proteases on the paracellular integrity of Calu-3, grown at the air-liquid interphase, was evaluated through a transepithelial permeability assay. Immunoblot and immunofluorescence experiments were performed to analyse the disruption of intercellular complexes. Degradation of bioactive peptides by pollen crude extracts was assessed by mass spectrometry.

RESULTS

All pollen diffusates were shown to have high molecular weight proteases with serine and/or aminopeptidase activity. These proteases increased Calu-3 transepithelial permeability through disruption of transmembrane adhesion proteins: occludin, claudin-1 and E-cadherin. Moreover, they were able to degrade airway bioactive peptides and were not blocked by endogenous protease inhibitors.

CONCLUSION

Pollen grains with distinct allergenic abilities release proteases that might be involved in the sensitization to a range of airborne allergens by facilitating allergen delivery across the epithelium and also contribute directly to the inflammation characteristic of allergic diseases.

Transthyretin binding to A-Beta peptide--impact on A-Beta fibrillogenesis and toxicity

It has been suggested that transthyretin (TTR) is involved in preventing A-Beta fibrillization in Alzheimer's disease (AD). Here, we characterized the TTR/A-Beta interaction by competition binding assays. TTR binds to different A-Beta peptide species: soluble (Kd, 28 nM), oligomers and fibrils; diverse TTR variants bind differentially to A-Beta. Transmission electron microscopy (TEM) analysis demonstrated that TTR is capable of interfering with A-Beta fibrillization by both inhibiting and disrupting fibril formation. Co-incubation of the two molecules resulted in the abolishment of A-Beta toxicity. Our results confirmed TTR as an A-Beta ligand and indicated the inhibition/disruption of A-Beta fibrils as a possible mechanism underlying the protective role of TTR in AD.

Impairment of the ubiquitin-proteasome system associated with extracellular transthyretin aggregates in familial amyloidotic polyneuropathy

The ubiquitin-proteasome system (UPS) has been associated with neurodegenerative disorders of intracellular protein aggregation. We have studied the UPS in familial amyloidotic polyneuropathy (FAP), a neurodegenerative disorder caused by extracellular deposition of mutant transthyretin (TTR). The studies were conducted in TTR-synthesizing and non-synthesizing tissues from affected individuals, in transgenic mouse models for FAP, and in neuronal or Schwannoma cell lines cultured with TTR aggregates. In human FAP tissues presenting extracellular TTR aggregates, ubiquitin-protein conjugates were up-regulated, the proteasome levels were decreased and parkin and alpha-synuclein expression were both decreased. A similar response was detected in mouse models for TTR V30M or L55P. On the other hand, the liver, which normally synthesizes variant TTR V30M, did not show this response. Furthermore, transgenic mice immunized to decrease TTR deposition showed a significant reduction in ubiquitin levels and an increase in parkin and alpha-synuclein levels in comparison to control mice. Studies performed in cell lines with aggregates in the medium resulted in increased ubiquitin and decreased parkin levels. The overall results are indicative of TTR deposition as an external stimulus to an intracellular UPS response in FAP.

Activation of ERK1/2 MAP kinases in Familial Amyloidotic Polyneuropathy

Familial amyloidotic polyneuropathy (FAP) is a neurodegenerative disorder characterized by the extracellular deposition of transthyretin (TTR), especially in the PNS. Given the invasiveness of nerve biopsy, salivary glands (SG) from FAP patients were used previously in microarray analysis; mitogen-activated protein (MAP) kinase phosphatase 1 (MKP-1) was down-regulated in FAP. Results were validated by RT-PCR and immunohistochemistry both in SG and in nerve biopsies of different stages of disease progression. MKP-3 was also down-regulated in FAP SG biopsies. Given the relationship between MKPs and MAPKs, the latter were investigated. Only extracellular signal-regulated kinases 1/2 (ERK1/2) displayed increased activation in FAP SG and nerves. ERK1/2 kinase (MEK1/2) activation was also up-regulated in FAP nerves. In addition, an FAP transgenic mouse model revealed increased ERK1/2 activation in peripheral nerve affected with TTR deposition when compared to control animals. Cultured rat Schwannoma cell line treatment with TTR aggregates stimulated ERK1/2 activation, which was partially mediated by the receptor for advanced glycation end-products (RAGE). Moreover, caspase-3 activation triggered by TTR aggregates was abrogated by U0126, a MEK1/2 inhibitor, indicating that ERK1/2 activation is essential for TTR aggregates-induced cytotoxicity. Taken together, these data suggest that abnormally sustained activation of ERK in FAP may represent an early signaling cascade leading to neurodegeneration.

Doxycycline disrupts transthyretin amyloid: evidence from studies in a FAP transgenic mice model

Familial amyloidotic polyneuropathy is an autosomal dominant disorder mainly characterized by the extracellular deposition of transthyretin, with special involvement of the peripheral nerve. Several animal models have been generated, including transgenic mice carrying the most prevalent TTR mutation (TTR Val30Met). TTR-Val30Met mice without endogenous TTR (TTR-Val30Met X TTR-KO) were previously analyzed in our laboratory and approximately 60% of the animals over 1 year of age were found to have deposition as amyloid, i.e., with Congo red (CR) -positive material, constituting a good tool to investigate the effect of drugs on TTR deposition and fibrillogenesis. We recently showed that the drug doxycycline acts in vitro as a TTR fibril disrupter. In the present work we assessed the activity of this drug in vivo in the TTR-Met30Val X TTR-KO mice. Doxycycline was administrated in the drinking water to 23- to 28-month-old mice over a period of 3 months. Immunohistochemistry analyses revealed no differences in nonfibrillar TTR deposition between treated (n=11) and untreated mice (n=11). However, CR-positive material was observed only in the control group (untreated) whereas none of the animals treated with doxycycline was CR-positive. Immunohistochemistry for several markers associated with amyloid, such as matrix metalloproteinase-9 (MMP-9) and serum amyloid P component (SAP), was performed. MMP-9 was altered with significantly lower levels in treated animals compared with the control group. Mouse SAP was absent in treated animals, being observed only in untreated animals presenting TTR congophilic deposits. These results indicate that doxycycline is capable of disrupting TTR CR-positive amyloid deposits and decreases standard markers associated with fibrillar deposition, being a potential drug in the treatment of amyloidosis.

Small Transthyretin (TTR) Ligands as Possible Therapeutic Agents in TTR Amyloidoses

In transthyretin (TTR) amyloidosis TTR variants deposit as amyloid fibrils giving origin, in most cases, to peripheral polyneuropathy, cardiomyopathy, carpal tunnel syndrome and/or amyloid deposition in the eye. More than eighty TTR variants are known, most of them being pathogenic. The mechanism of TTR fibril formation is still not completely elucidated. However it is widely accepted that the amino acid substitutions in the TTR variants contribute to a destabilizing effect on the TTR tetramer molecule, which in particular conditions dissociate into non native monomeric intermediates that aggregate and polymerize in amyloid fibrils that further elongate. Since this is a multi-step process there is the possibility to impair TTR amyloid fibril formation at different stages of the process namely by tetramer stabilization, inhibition of fibril formation or fibril disruption. Till now the only efficient therapy available is liver transplant when performed in an early phase of the onset of the disease symptoms. Since this is a very invasive therapy alternatives are desirable. In that sense, several compounds have been proposed to impair amyloid formation or disruption. Based on the proposed mechanism for TTR amyloid fibril formation we discuss the action of some of the proposed TTR stabilizers such as derivatives of some NSAIDs (diflunisal, diclofenac, flufenamic acid, and derivatives) and the action of amyloid disrupters such as 4'-iodo-4'-deoxydoxorubicin (I-DOX) and tetracyclines. Among all these compounds, TTR stabilizers seem to be the most interesting since they would impair very early the process of amyloid formation and could also have a prophylactic effect.

Transthyretin fibrillogenesis entails the assembly of monomers: a molecular model for in vitro assembled transthyretin amyloid-like fibrils

Extracellular accumulation of transthyretin (TTR) variants in the form of fibrillar amyloid deposits is the pathological hallmark of familial amyloidotic polyneuropathy (FAP). The TTR Leu55Pro variant occurs in the most aggressive forms of this disease. Inhibition of TTR wild-type (WT) and particularly TTR Leu55Pro fibril formation is of interest as a potential therapeutic strategy and requires a thorough understanding of the fibril assembly mechanism. To this end, we report on the in vitro assembly properties as observed by transmission electron microscopy (TEM), atomic force microscopy (AFM) and quantitative scanning transmission electron microscopy (STEM) for both TTR WT fibrils produced by acidification, and TTR Leu55Pro fibrils assembled at physiological pH. The morphological features and dimensions of TTR WT and TTR Leu55Pro fibrils were similar, with up to 300 nm long, 8 nm wide fibrils being the most prominent species in both cases. Other species were evident; 4-5 nm wide fibrils, 9-10 nm wide fibrils and oligomers of various sizes. STEM mass-per-length (MPL) measurements revealed discrete fibril types with masses of 9.5 and 14.0(+/-1.4) KDa/nm for TTR WT fibrils and 13.7, 18.5 and 23.2(+/-1.5) kDa/nm for TTR Leu55Pro fibrils. These MPL values are consistent with a model in which fibrillar TTR structures are composed of two, three, four or five elementary protofilaments, with each protofilament being a vertical stack of structurally modified TTR monomers assembled with the 2.9 nm axial monomer-monomer spacing indicated by X-ray fibre diffraction data. Ex vivo TTR amyloid fibrils were examined. From their morphological appearance compared to these, the in vitro assembled TTR WT and Leu55Pro fibrils examined may represent immature fibrillar species. The in vitro system operating at physiological pH for TTR Leu55Pro and the model presented for the molecular arrangement of TTR monomers within fibrils may, therefore, describe early fibril assembly events in vivo.

Deposition of transthyretin in early stages of familial amyloidotic polyneuropathy: evidence for toxicity of nonfibrillar aggregates

Familial amyloidotic polyneuropathy (FAP) is a neurodegenerative disorder characterized by extracellular deposition of transthyretin (TTR) amyloid fibrils, particularly in the peripheral nervous system. No systematic immunohistochemical data exists relating TTR deposition with FAP progression. We assessed nerves from FAP patients in different stages of disease progression (FAP 0 to FAP 3) for TTR deposition by immunohistochemistry, and for the presence of amyloid fibrils by Congo Red staining. The nature of the deposited material was further studied by electron microscopy. We observed that early in FAP (FAP 0), TTR is already deposited in an aggregated nonfibrillar form, negative by Congo Red staining. This suggested that in vivo, preamyloidogenic forms of TTR exist in the nerve, in a stage before fibril formation. Cytotoxicity of nonfibrillar TTR was assessed in nerves of different FAP stages by immunohistochemistry for macrophage colony-stimulating factor. FAP 0 patients already presented increased axonal expression of macrophage colony-stimulating factor that was maintained in all other stages, in sites related to TTR deposition. Toxicity of synthetic TTR fibrils formed in vitro at physiological pH was studied on a Schwannoma cell line by caspase-3 activation assays and showed that early aggregates but not mature fibrils are toxic to cells. Taken together, these results show that nonfibrillar cytotoxic deposits occur in early stages of FAP.

Tetramer dissociation and monomer partial unfolding precedes protofibril formation in amyloidogenic transthyretin variants

Amyloid fibril formation and deposition is a common feature of a wide range of fatal diseases including spongiform encephalopathies, Alzheimer's disease, and familial amyloidotic polyneuropathies (FAP), among many others. In certain forms of FAP, the amyloid fibrils are mostly constituted by variants of transthyretin (TTR), a homotetrameric plasma protein. Recently, we showed that transthyretin in solution may undergo dissociation to a non-native monomer, even under close to physiological conditions of temperature, pH, ionic strength, and protein concentration. We also showed that this non-native monomer is a compact structure, does not behave as a molten globule, and may lead to the formation of partially unfolded monomeric species and high molecular mass soluble aggregates (Quintas, A., Saraiva, M. J. M., and Brito, R. M. M. (1999) J. Biol. Chem. 274, 32943-32949). Here, based on aging experiments of tetrameric TTR and chemically induced protein unfolding experiments of the non-native monomeric forms, we show that tetramer dissociation and partial unfolding of the monomer precedes amyloid fibril formation. We also show that TTR variants with the least thermodynamically stable non-native monomer produce the largest amount of partially unfolded monomeric species and soluble aggregates under conditions that are close to physiological. Additionally, the soluble aggregates formed by the amyloidogenic TTR variants showed morphological and thioflavin-T fluorescence properties characteristic of amyloid. These results allowed us to conclude that amyloid fibril formation by some TTR variants might be triggered by tetramer dissociation to a compact non-native monomer with low conformational stability, which originates partially unfolded monomeric species with a high tendency for ordered aggregation into amyloid fibrils. Thus, partial unfolding and conformational fluctuations of molecular species with marginal thermodynamic stability may play a crucial role on amyloid formation in vivo.

4'-Iodo-4'-deoxydoxorubicin disrupts the fibrillar structure of transthyretin amyloid

Transthyretin (TTR) is a tetrameric protein synthesized mainly by the liver and the choroid plexus, from where it is secreted into the plasma and the cerebrospinal fluid, respectively. Some forms of polyneuropathy, vitreopathy, and cardiomyopathy are caused by the deposition of normal and/or mutant TTR molecules in the form of amyloid fibrils. Familial amyloidotic polyneuropathy is the most common form of TTR amyloidosis related to the V30M variant. It is still unclear the process by which soluble proteins deposit as amyloid. The treatment of amyloid-related disorders might attempt the stabilization of the soluble protein precursor to retard or inhibit its deposition as amyloid; or aim at the resorption of the deposited amyloid. The anthracycline 4'-iodo-4'-deoxydoxorubicin (I-DOX) has been shown to reduce the amyloid load in immunoglobulin light-chain amyloidosis. We investigated 1) whether I-DOX has affinity for TTR amyloid in tissues, 2) determined the I-DOX binding constants to TTR synthetic fibrils, and 3) determined the nature of the effect of I-DOX on TTR fibrils. We report that 1) I-DOX co-localizes with amyloid deposits in tissue sections of patients with familial amyloidotic polyneuropathy; 2) I-DOX strongly interacts with TTR amyloid fibrils and presents two binding sites with k(d) of 1.5 x 10(-11) mol/L and 5.6 x 10(-10) mol/L, respectively; and 3) I-DOX disrupts the fibrillar structure of TTR amyloid into amorphous material, as assessed by electron microscopy but does not solubilize the fibrils as confirmed by filter assays. These data support the hypothesis that I-DOX and less toxic derivatives can prove efficient in the treatment of TTR-related amyloidosis.

Aprotinin binding to amyloid fibrils

Different low molecular mass ligands have been used to identify amyloid deposits. Among these markers, the dyes Thioflavin T and Congo Red interact specifically with the beta-sheet structure arranged in a cross-beta conformation, which is characteristic of amyloid. However, the molecular details of this interaction remain unknown. When labelled with technetium-99m, the proteinase inhibitor aprotinin has been shown to represent a very important radiopharmaceutical agent for in vivo imaging of extra-abdominal deposition of amyloid in amyloidosis of the immunoglobulin type. However, no information is available as to whether aprotinin binds other types of amyloid fibrils and on the nature and characteristics of the interaction. The present work shows aprotinin binding to insulin, transthyretin, beta-amyloid peptide and immunoglobulin synthetic amyloid fibrils by a specific dot-blot ligand-binding assay. Aprotinin did not bind amorphous precipitates and/or the soluble fibril precursors. A Ka of 2.9 microM-1 for the binding of aprotinin to insulin amyloid fibrils was determined by Scatchard analysis. In competition experiments, analogues such as an aprotinin variant, a spermadhesin and the soybean trypsin inhibitor were tested and results suggest that both aprotinin and the spermadhesin interact with amyloid fibrils through pairing of beta-sheets of the ligands with exposed structures of the same type at the surface of amyloid deposits. An electrostatic component may also be involved in the binding of aprotinin to amyloid fibrils because important differences in binding constants are observed when substitutions V15L17E52 are introduced in aprotinin; on the other hand beta-sheet containing acidic proteins, such as the soybean trypsin inhibitor, are unable to bind amyloid fibrils.

Latex particle agglutination test in the diagnosis of Haemophilus influenzae type B, Streptococcus pneumoniae and Neisseria meningitidis A and C meningitis in infants and children

The knowledge of purulent meningitis etiology is essential in deciding the immediate therapy; in developing countries, however, the etiological agent identification does not reach 60% of the cases. A comparative study using the latex particle agglutination test (LPAT) in cerebrospinal fluid (CSF) for the diagnosis of meningitis due to Haemophilus influenzae type b, Streptococcus pneumoniae or Neisseria meningitidis A and C was carried out in Belo Horizonte MG, Brazil. CSF culture was used as a gold-standard. Two hundred and ninety-nine children, ranging from 3 months to 14 years of age, were included in the investigation. One hundred and forty-four presented a positive CSF culture for the above mentioned bacteria; the remaining presented meningitis due to other organisms (other bacteria or viral) or a normal CSF. The sensitivity and the specificity of LPAT was 95.7 and 100.0% for N. meningitidis C, 95.2 and 100.0% for H. influenzae type b and 86.5 and 100.0% for S. pneumoniae, respectively. When all three organisms were considered simultaneously, the sensitivity and the specificity was 93.0 and 100.0%, respectively. Taking into consideration a realistic estimate of disease prevalence in the community where the diagnostic test is being used, the positive predictive value and the posttest probability were estimated as 36.7 and 47.1% for children < 5 years and as 21.3 and 35.1% for children < 14 years of age, respectively. LPAT is a useful diagnostic test for meningitis due to the studied pathogens, especially in developing countries where laboratory facilities are limited.