Normal flow, low gradient aortic stenosis - is LVOT the determinant?

Funding Acknowledgements

Type of funding sources: None.

Introduction

Severe aortic stenosis is characterized for a high mean gradient (>40mmHg) and an aortic valve area (AVA ≤1cm2). These patients present with a lower mean gradient (<40mmHg) and area (AVA ≤1cm2). However, the treatment strategies focus on the population with a reduced indexed stroke volume (≤35mL/m2). There is less clarity concerning those with a normal stroke volume. An important determinant of the area and stroke volume is the LVOT diameter, which may have a significant impact in the classification of the severity. There is some literature supporting an expected diameter according to the body surface area.

Purpose

This paper aims to analyse the population with normal flow, low gradient aortic stenosis, as well as compare the impact of the expected LVOT diameter in the classification of patients.

Methods

We present a retrospective study from all consecutive patients to whom an echocardiogram was performed in our hospital during the years 2017 and 2018 which meet the criteria for low gradient aortic stenosis. Comorbidities were analysed as well as echocardiographic variables to properly characterize aortic stenosis.

Results

A total of 79 patients met the criteria for normal flow, low gradient aortic stenosis with a valvular area ≤1cm2.  Mean age was 79.5 ± 8.6 years-old and 38% was male. The mean LVOT diameter was 2.11 ± 0.18 cm which correlated to a mean AVA of 0.88 ± 0.10 cm2. Should the LVOT diameter align with the expected diameter according to the formula [(5,7× BSA +12,1)/10], the mean LVOT diameter would be 2.18 ± 0.11 cm, which correlated to a mean AVA of 0.96 ± 0.22cm2. This represents a statistically significant difference in the value, with the expected diameter being 0.075cm higher than the measured (p = 0.002), which translates in a statistically significant higher AVA (+0.085, p < 0,001). With the above data, 31 (38.8%) patients would have been reclassified as moderate aortic stenosis, according to the recalculated AVA alone. Taking into account the indexed AVA, only 22 (27.8%) patients would be reclassified. 8 other patients (10.1%) would have been reclassified as low flow, low gradient aortic stenosis as the recalculated stroke volume would be lower than 35mL/m2.

Conclusion

This paper reminded us of the importance of an appropriately measured LVOT diameter, and the potential impact in reclassification of valvular heart disease. This is more important when the classification may alter our conduct. Other imaging techniques, such as transoesophageal echocardiogram or CT scan, may obviate the squared error of the LVOT measurement as well as account for the geometry of the LVOT, especially in dubious cases. Abstract Figure.

Is flow better in mL/m2 or mL/s - a practical reflection on aortic stenosis

Funding Acknowledgements

Type of funding sources: None.

Introduction

Severe aortic stenosis is characterized for a high mean gradient (>40mmHg) and an aortic valve area (AVA ≤1cm2). There is a population of patients with discordant findings. These patients present with a lower mean gradient (<40mmHg) and area (AVA ≤1cm2).  This states are explained by a low flow (indexed SV ≤35ml/m2). Some studies demonstrated that a flow rate (determined by dividing SV by ejection time) inferior to 200 mL/s is also associated with poor prognosis. Can this be an alternative in stratifying patients with an AVA ≤1cm2?

Purpose

This paper aims to compare flow assessment by the conventional way with flow calculated in ml/s in patients with AVA ≤1cm2

Methods

We present a retrospective study from all consecutive patients to whom an echocardiogram was performed in our hospital during the years 2017 and 2018 which meet the criteria for low gradient aortic stenosis. Comorbidities were analysed for each subgroup as well as echocardiographic variables to properly characterize aortic stenosis.

Results

A total of 118 patients met the criteria for severe aortic stenosis with a valvular area ≤1cm2. This population was made up of 18 patients with severe aortic stenosis low flow, low gradient with depressed ejection fraction and 32 patients with preserved ejection fraction. The other 68 patients represented patients with a normal flow, low gradient aortic stenosis. There is a strong correlation between the variable SVi and Flow Rate (r = 0,796, p < 0,001). A linear regression shows that the flow rate equivalent to a SVi of 35mL/m2 in our sample is 203mL/s, near the value of other studies. 10 (31.3%) patients with severe aortic stenosis low flow, low gradient with preserved ejection fraction, 3 (16.7%) patients with severe aortic stenosis low flow, low gradient with depressed ejection fraction and 53 (77.9%) patients with normal flow, low gradient aortic stenosis would have a flow superior to 200mL/s.

Conclusion

The use of flow rate systematically would downgrade the severity of valvular lesions with possible need for intervention. However, in certain dubious cases its application may identify a subpopulation with need for further study and probable treatment, such as the patients with normal flow, low gradient aortic stenosis. Further studies of this subgroup of patients are warranted to reach any final conclusions. Abstract Figure.

Low gradient aortic stenosis - is survival that different between types and strategies

Funding Acknowledgements

Type of funding sources: None.

Introduction

Severe aortic stenosis is characterized for a high mean gradient (>40mmHg) and an aortic valve area (AVA ≤1cm2). There is a population of patients with discordant findings. These patients present with a lower mean gradient (<40mmHg) and a small area (AVA ≤1cm2). They encompass a population with specific characteristics and rather heterogeneous treatment approach and different prognosis

Purpose

This paper aims to enlighten to the prognosis of the different subpopulation of low gradient aortic stenosis, alone and according to the treatment strategies in a center without surgical ou percutaneous valvular intervention. 

Methods

We present a retrospective study from all consecutive patients to whom an echocardiogram was performed in our hospital during the years 2017 and 2018 which meet the criteria for low gradient aortic stenosis. Comorbidities were analysed for each subgroup as well as echocardiographic variables to properly characterize aortic stenosis and employed strategy and death.

Results

A total of 135 patients met the criteria for severe aortic stenosis with a valvular area ≤1cm2. This population was made up of 19 patients with severe aortic stenosis low flow, low gradient with depressed ejection fraction and 36 patients with preserved ejection fraction. The other 80 patients represented patients with a normal flow, low gradient aortic stenosis. Groups were similar in terms of age, sex, BMI, hypertension, dyslipidaemia, atrial fibrillation, chronic obstructive pulmonary disease, chronic kidney disease and chronic coronary syndrome. In terms of diabetes there was a statistically significant difference (p = 0.019) with a lower prevalence in the group with low flow, low gradient and preserved ejection fraction. There was a statistically significant difference in survival at 24 months between groups (p = 0,004), with a mean survival of 13.6 months, 17.6months and 21 months for low flow low gradient with depressed ejection fraction, low flow low gradient with preserved ejection fraction and normal flow, low gradient patients, respectively. When analysing the treatment strategies, there were also statistically significant differences between the whole population of patients (p = 0.001) and each subgroup (low flow, low gradient with depressed ejection fraction – p <0,001; and normal flow low gradient – p = 0,005), with exception of patients with low flow low gradient and preserved ejection fraction (p = 0,081).

Conclusion

Our analyses brings to our attention a clear difference in prognosis between the subgroups analysed with a worse mean survival at 24 months in patients with low flow, low gradient and depressed ejection fraction. Furthermore, there seems to be a clear impact of treatment strategies in each group of patients and still some margin of improvement especially in patients without a clearly defined treatment strategy. Abstract Figure.  Abstract Figure.

P1461 Concomitant potential cardioembolic sources in a patient with an acute ischemia of the limb

Introduction

Transesophageal echocardiography (TEE) is the gold standard exam to look for a cardioembolic source in a patient with an otherwise unexplained suspected systemic ischemic event. Purpose: This clinical case aims to illustrate the importance of a thorough TEE evaluation in the presence of a suspected systemic emboli, and to not neglect thoracic aorta evaluation when a potential intracardiac cause has been detected. Case presentation: We present the case of a 55-year-old man, obese (BMI 30kg/m2), active smoker, with no past medical history or medication, and whose father died from an unspecified cardiovascular cause at 45 years-old. He was admitted to the hospital because of an acute ischemia of the right lower limb, for which he underwent urgent percutaneous femoral embolectomy of the limb, with success. During hospitalization, he was referred for a TEE, which showed valves and cavities with no evidence of potential embolic sources. However, he had a thin and hypermobile atrial septum, with no obvious defect after color flow mapping, but with a patent foramen oval (PFO) that was detected after agitated saline injection associated with a Valsalva maneuver, with the passage of 5-25 microbubbles (grade 2/4 shunt) and an atrial septum aneurysm (ASA), with an excursion of the fossa ovalis towards the left atrium of 10.1mm (Figure 1). The ascending aorta was normal, but the descending aorta depicted 2 hypermobile masses, 1 starting at 35cm from the dental arch (transversal area: 0,52cm2), the longest (7cm) starting at 32cm and ending at the aortic arch (transversal area: 1,76cm2). An angio-CT was immediately performed, which depicted an atheromatous calcified plaque in the terminal portion of the aortic arch, giving rise to the image suggestive of thrombus, and extending for about 6cm to the medium third of the descending thoracic aorta. The remaining portions of the aorta and iliac arteries depicted diffuse atheromatous and partially calcified plaques (Figure 2). The patient was submitted to an urgent thoracic endovascular aortic repair with a 26x10cm prosthesis implantation with occlusion of the left subclavian artery and an adequate final clinical result. Syphilis and auto-immune disease were excluded and a diffuse atheromatous disease of the aorta was assumed as the cause of the thrombus and the embolic event. After 16 days, he was discharged asymptomatic and with no signs of chronic ischemia, treated with oral anticoagulation with rivaroxabano, high-dose statin and strict smoking cessation. Conclusion: Cardioembolic source is a heterogeneous entity. In this patient, 2 potential cardioembolic sources were detected: while the PFO and ASA are minor or unclear risk sources of emboli, TEE also allowed for the detection of a large thrombus arising from an atherosclerotic calcified plaque in the thoracic aorta, which was considered a major risk source, thus implying urgent surgery to obviate the risk of further embolic events.

Abstract P1461 Figure. Fig.1.POF and ASA;Fig.2.Aortic Thrombus

P1788 Prognostic value of stress echocardiography in preoperative risk stratification and management

Introduction

The prognostic value of pharmacologic stress echocardiography has been extensively demonstrated in patients undergoing noncardiac surgery since 42% of the perioperative complications are cardiac. Coronary artery stenoses can became flow-limiting due to hemodynamic fluctuations in this period leading to myocardial ischemia.

Purpose

Evaluation of prognostic value of pharmacologic stress echocardiography in preoperative risk stratification.

Methods

Single center retrospective analysis of patients’ data referred to perform a preoperative risk stratification through pharmacological stress echocardiography between January 2014- December 2018. Data was collected regarding clinical and echocardiographic parameters to predict perioperative cardiac complications (myocardial infarction and development of arrythmias) and evaluate the impact of the result of DSE in patients´ clinical management.

Results

Of 910 pharmacological stress echocardiograms, 106 were performed to evaluate preoperative risk. Patients´ mean age was 66 ± 11 years, 85% males. 64% had hypertension, 45% dyslipidaemia, 38% current smokers and 18% diabetes. 189% had previously myocardial infarction and 9% stroke. All patients were proposed to intermediate-high risk surgeries: 73% to vascular surgery, 14% to kidney transplant and 13% to other type of surgery (especially abdominal surgery). Most of the stress tests (64%) were performed with dobutamine and the others 34% with dipyridamole. 91% of stress echocardiography were negative, 6% positive and 4% inconclusive. The patients with a positive stress test was submitted to coronary angiography to treat relevant lesions and cardiovascular risk factors were optimized. 72% of the patients has already been submitted to the proposed surgery; in this population, there was a 5% rate of cardiac complications following the surgery, all in patients with previous negative stress echocardiography. Complications were non-ST elevation myocardial infarction in 1% and de novo atrial fibrillation in 4%. Half of the patients with a positive stress echocardiography were operated with no cardiac perioperative complications, possibly related to patient´s optimization before the surgery; in the other half it was decided not to perform the surgery due to the potential cardiac risk. Predictor factors for perioperative cardiac complications, evaluated through univariate and multivariate analysis, were age (odds ratios (OR) 1.232, confidence interval (CI) 1.043-1.456, p 0.007) and stroke (OR 0.057, CI 0.947-44.592, p 0.033).

Conclusion

In our study, patients with a positive stress echocardiography were optimized before the surgery leading to none cardiac perioperative complications, emphasizing the importance of this test in preoperative patients´ management.

2210Symptomatic severe aortic stenosis: predictor factors and outcomes

Introduction

The natural history in aortic stenosis (AS) is a slowly progressive process which begins as aortic sclerosis and subsequently progresses to severe opening restriction, conditioning symptoms development. At this time, surgical aortic valve replacement is strongly recommended due to its poor prognosis.

Purpose

Evaluation of predictor factors of symptomatic severe AS and its prognostic impact.

Methods

Single center retrospective analysis of patients' data accompanied in cardiology consultation due to severe AS diagnosed between 2015–2016. Data was collected regarding clinical and echocardiographic parameters to determine predictor factors of stablished endpoints.

Results

150 patients were reviewed, mean age 76.6±9.0 years, 72% males. 68.7% had hypertension, 42% dyslipidaemia and 32.7% diabetes. 64.7% of the patients had symptoms attributable to severe AS: 48% dyspnoea, 12% angina and 4.7% syncope. 7.3% of the patients were hospitalized due to acute heart failure in this context. Comparing echocardiographic parameters between symptomatic versus non-symptomatic patients with severe AS, symptomatic patients had higher values of aortic maximum velocity (4.5±0.5 vs 4.3±0.4 m/sec, p<0.001) and mean gradient (50.1±12.7 vs 43.2±7.7 mmHg, p<0.001). There were no significant differences regarding mean aortic valvular area neither left ventricle ejection fraction. At univariate analysis, predictor factors of symptoms attributable to severe AS development were: hypertension (odds ratio (OR) 2.044, confidence interval (CI) 1.004–4.161, p 0.049), anaemia (OR 0.420, CI 0.207–0.851, p 0.016), aortic maximum velocity (OR 5.497, CI 2.014–15.000, p 0.001) and mean gradient (OR 1.073, CI 1.029–1.118, p 0.001). At multivariate analysis, only aortic maximum velocity showed to be independent predictor factor of symptomatic severe AS (p 0.012). Hospitalization and all-cause mortality rates (respectively: 9.3 vs 9.4%, p 0.975; and 25.8 vs 34%, p 0.305) did not differ between groups.

Conclusion

In patients with severe AS, aortic maximum velocity showed to be the only independent predictor factor of symptoms development, however it was not associated with an increased hospitalization or mortality rates.

Characterization of Raphanus sativus pentatricopeptide repeat proteins encoded by the fertility restorer locus for Ogura cytoplasmic male sterility

Cytoplasmic male sterility is a maternally inherited trait in higher plants that prevents the production of functional pollen. Ogura cytoplasmic male sterility in radish (Raphanus sativus) is regulated by the orf138 mitochondrial locus. Male fertility can be restored when orf138 accumulation is suppressed by the nuclear Rfo locus, which consists of three genes putatively encoding highly similar pentatricopeptide repeat proteins (PPR-A, -B, and -C). We produced transgenic rapeseed (Brassica napus) plants separately expressing PPR-A and PPR-B and demonstrated that both encoded proteins accumulated preferentially in the anthers of young flower buds. Immunodetection of ORF138 showed that, unlike PPR-B, PPR-A had no effect on the synthesis of the sterility protein. Moreover, immunolocalization experiments indicated that complete elimination of ORF138 from the tapetum of anthers correlated with the restoration of fertility. Thus, the primary role of PPR-B in restoring fertility is to inhibit ORF138 synthesis in the tapetum of young anthers. In situ hybridization experiments confirmed, at the cellular level, that PPR-B has no effect on the accumulation of orf138 mRNA. Lastly, immunoprecipitation experiments demonstrated that PPR-B, but not PPR-A, is associated with the orf138 RNA in vivo, linking restoration activity with the ability to directly or indirectly interact with the orf138 RNA. Together, our data support a role for PPR-B in the translational regulation of orf138 mRNA.