The impact of the COVID-19 pandemic on transcatheter aortic valve implantation (TAVI) service: a United Kingdom tertiary centre experience

Background/Introduction

Untreated, symptomatic, severe aortic stenosis carries significant mortality and morbidity. Timely intervention is pivotal to ensure patient safety. The COVID-19 pandemic created unprecedented challenges to the UK's National Health Service (NHS), resulting in the deferral of all elective work, including TAVI services from March 2020.

Purpose

To evaluate clinical outcomes and time delays in patients undergoing TAVI during the pandemic period compared to an age and risk factor-matched cohort of patients prior to COVID-19. We hypothesized that there were significant time delays, more emergency procedures and related adverse outcomes in patients who underwent TAVI during the pandemic period.

Methods

We analysed prospectively collected data (patient characteristics, procedural details, complications and in-hospital outcomes) of 210 consecutive patients who underwent TAVI between March 2019 and February 2021 in a tertiary centre in the UK (The centre serves for a population of 2.5 million and provided in-patient treatment for 5590 COVID-positive patients over a 12 month period). We compared time-lags from an initial referral to outpatient review, CT aortograms, valve implantation and 30-day mortality between patients who underwent TAVI between March 2019 and Feburary 2020 (N=134) and those who underwent TAVI between March 2020 and February 2021 (COVID Group=76).

Results

The mean age of the cohort was 81.4±6.6 years and majority were females (51%) and were in moderate risk category (EuroSCORE II=4.55±5.5). Of the total cohort, 4 (5.3%) patients acquired COVID-19 pneumonia during the hospital stay. The age, cardiovascular comorbidities and risk scores were comparable between the control group and the COVID cohort. (Table 1). There were no significant differences in procedural complications in the control group compared to the COVID-19 group (Table 1). The median waiting time from referral to TAVI clinic was significantly shorter in the COVID-19 group (33 (8–66) vs. 51 (17–89) days (P=0.04)) and there was no significant difference in time delays for CT aortogram, MDT or TAVI procedure between the two groups. The median length of stay (2 (2–4) vs 2.5 (2–9) days) and 30 day mortality (1.4% vs 5.3%) was comparable between the two groups (Table 1).

Conclusion

Contrary to our hypothesis, our analysis demonstrated that there were no significant time delays, excess complications or mortality in TAVI procedures during the COVID-19 pandemic period despite the excess burden imposed on our local health services. More importantly, very few TAVI patients acquired COVID-19 infection during in-hospital stay. This is likely due to prompt identification of innovative ways of re-configuring an existing local patient pathway, by the TAVI team, to deliver safe and uninterrupted TAVI services during this unprecedented pandemic setting.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Referral times

Clinical outcomes up-to 10 years of asymptomatic incidental aortic dissections and large aortic aneurysms detected on computer tomography aortography (CTA) prior to transcatheter aortic valve implantation (TAVI)

Background/Introduction

Computer tomography aortography (CTA) is performed routinely to aid planning of transcatheter aortic valve implantation (TAVI). Incidental findings are common, and may influence the decision to proceed with TAVI. The safety and long term outcomes of performing TAVI in patients with previously undiagnosed incidental CT findings of aortic dissections and large aortic aneurysms is currently unknown.

Purpose

To establish the frequency of incidental aortic dissections and large aortic aneurysms prior to TAVI, and subsequent clinical outcomes of patients. We hypothesize that transfemoral access is safe in patients with incidental finding of aortic dissection and large aortic aneurysms.

Methods

This was a retrospective study of 628 sequential TAVI patients in a large, UK tertiary centre between January 2010 and September 2020. Patients were evaluated in 3 groups as per pre-TAVI CTA: incidental aortic dissections, aortic aneurysm >4cm and all others (control group). Endpoints were procedural success, peri-procedural major bleeding and/or vascular complications and/or CVA, length of hospital stay, 30-day and 1-year mortality.

Results

2.9% of patients (n=18) had incidental aortic dissection, of which 66.7% (n=12) were male, with a mean age of 86.7±4.4. 3.8% of patients (n=24) had aortic aneurysms >4 cm. 83.3% (n=20) of them were male and the mean age was 82.8±5.4. Transfemoral approach was favoured in 77.8% of patients in the dissection group and 83.3% of patients in the aneurysm group versus 93.3% in the control group. Procedural characteristics are summarised in Table 1. Vascular access complications, stroke, bleeding and length of hospital stay were comparable between all 3 groups (Table 1). Patients with dissection and large aneurysm had similar success rate of valve implantation compared to the control group (88.9% and 87.5% vs 97.1%, p=0.452). 30-day mortality in the dissection group was higher than the other 2 groups (21.1% vs 0% and 5.6%, p=0.004). Log-rank analysis revealed a higher incidence of MACE in the dissection group over 24 months compared to the other two groups (Figure 1).

Conclusion

A transfemoral approach appears to be a safe choice in patients with incidental findings of aortic dissection or aortic aneurysms >4cm, given no significant difference in terms of valve implant success, vascular injury, major bleeding or unplanned surgical repair. However, patients with stable previous aortic dissections have a significantly higher 30-day mortality and overall lower survival rate over 24 months. This important observation needs to be further investigated in a larger-scale, long-term follow up study, and may in future influence TAVI treatment planning.

Funding Acknowledgement

Type of funding sources: None. Figure 1. Survival curve

Contextualising gender intersectionality with the COVID-19 pandemic

Objectives

To explore the association of gender inequality index (GII) with healthcare access and quality index (HAQI) for the male to female ratio of confirmed COVID-19 cases.

Study design

Secondary analysis of COVID-19 cases with GII and HAQI datasets.

Methods

Data for sex-disaggregated COVID-19 cases were collected from Global Health 50/50, for GII from the United Nations Development Programme (UNDP) and for HAQI from the Institute for Health Metrics and Evaluation (IHME). We used Spearman's correlation in SPSS version 23 to evaluate the association between the variables.

Results

Cambodia had the highest male to female ratio (M:F) of 4.08:1, followed by Pakistan (M:F = 2.85:1) and Nepal (M:F = 2.69:1). We observed a positive correlation between GII and M:F ratio (Spearman's rho = 0.681, P-value <0.001) and a negative correlation between HAQI and M:F ratio (Spearman's rho = −0.676, P-value <0.001).

Conclusions

Countries with institutionalised gender disparities and poor healthcare access and quality tend to have higher M:F ratios of confirmed COVID-19 cases; thus, highlighting underutilisation of testing services, influenced by multiple individuals, social and policy factors. Robust gender-based data are required to understand disparities throughout the continuum of care and to devise gender-responsive pandemic strategies.

A porcine Model of Intimal-Medial Hyperplasia in Polytetrafluoroethylene Arteriovenous Grafts

Purpose

Vascular access polytetrafluoroethylene (PTFE) graft failure is a major cause of morbidity in the hemodialysis population. The most common cause of graft failure is thrombosis secondary to stenosis at the venous outflow tract. Venous outflow stenosis is characterized by intimal-medial hyperplasia. We have developed a porcine arteriovenous (AV) graft model that may be used to investigate this proliferative response and aid in the development of new therapies to prevent intimal-medial hyperplasia and improve graft patency.

Methods

Left carotid to right external jugular vein PTFE (6 mm) grafts were implanted in the necks of swine. Immediately following anatomosis, flow rates were recorded. In one group of animals (n = 4) the venous outflow tract was harvested after 7 days and morphometric analysis of intimal and medial area was performed. In a second group (n = 8) the graft patency was monitored until 28 days.

Results

All porcine PTFE fistula grafts were patent at 7 days and 100% patency was maintained until 14 days. After 28 days, 75% of the grafts failed due to thrombosis. The venous outflow tract developed a significant proliferative response. After 7 days the intimal and medial areas were 469 ± 9 μm2 and 875 ± 26 μm2 respectively. At 28 days the intimal and medial areas were 913 ± 55 μm2 and 1437 ± 182 μm2 respectively. Luminal flow rate of the venous outflow tract was reduced significantly (344 ± 11 ml/min at Day 0 to 129 ± 14 ml/min at Day 7, p < 0.05).

Conclusions

This porcine model rapidly, reliably and robustly reproduces the flow reducing stenosis and intimal-medial hyperplasia at the venous outflow tract of PTFE arteriovenous fistula. It represents a promising tool for investigating the mechanisms of intimal-medial hyperplasia, evaluating therapeutic interventions and new graft materials.

African-American inflammatory bowel disease in a Southern U.S. health center

Background

Inflammatory Bowel Diseases (IBD) remain significant health problems in the US and worldwide. IBD is most often associated with eastern European ancestry, and is less frequently reported in other populations of African origin e.g. African Americans ('AAs'). Whether AAs represent an important population with IBD in the US remains unclear since few studies have investigated IBD in communities with a majority representation of AA patients. The Louisiana State University Health Sciences Center in Shreveport (LSUHSC-S) is a tertiary care medical center, with a patient base composed of 58% AA and 39% Caucasian (W), ideal for evaluating racial (AA vs. W) as well and gender (M vs. F) influences on IBD.

Methods

In this retrospective study, we evaluated 951 visits to LSUHSC-S for IBD (between 2000 to 2008) using non-identified patient information based on ICD-9 medical record coding (Crohn's disease 'CD'-555.0- 555.9 and ulcerative colitis 'UC'-556.0-556.9).

Results

Overall, there were more cases of CD seen than UC. UC and CD affected similar ratios of AA and Caucasian males (M) and females (F) with a rank order of WF > WM > AAF > AAM. Interestingly, in CD, we found that annual visits per person was the highest in AA M (10.7 ± 1.7); significantly higher (* -p < 0.05) than in WM (6.3 ± 1.0). Further, in CD, the female to male (F: M) ratio in AA was significantly higher (*- p < 0.05) (1.9 ± 0.2) than in Caucasians (F:M = 1.3 ± 0.1) suggesting a female dominance in AACD; no differences were seen in UC F: M ratios.

Conclusion

Although Caucasians still represent the greatest fraction of IBD (~64%), AAs with IBD made up >1/3 (36.4%) of annual IBD cases from 2000-2008 at LSUHSC-S. Further studies on genetic and environments risks for IBD risk in AAs are needed to understand differences in presentation and progression in AAs and other 'non-traditional' populations.

Creatine kinase isoforms as circulating markers of deterioration in idiopathic dilated cardiomyopathy

BACKGROUND

A proportion of patients with dilated cardiomyopathy (DCM) may have ongoing myocardial damage secondary to viral or immune mediated myocardial inflammation.

HYPOTHESIS

The prognostic determinants identify patients with decreased survival but do not provide a measure of myocardial damage. To obtain an objective assessment of myocardial damage in DCM, we measured plasma levels of creatine kinase (CK), its isoenzymes (CK-MM and CK-MB), and separated the isoforms of CK-MM and CK-MB.

METHODS

The cohort consisted of 77 consecutive patients (61 men, 16 women) with DCM (World Health Organization criteria), aged 49 +/- 14 years (range 19-60). Patients had been symptomatic for 29 +/- 38 months (range 0.5-200 months) with 48 in New York Heart Association class I/II and 29 in class III/IV at the time of diagnosis. During median follow-up of 27 months from diagnosis (range 0.6-165), 50 patients remained clinically stable and 27 had deteriorated.

RESULTS

A significantly higher proportion of patients with DCM had abnormal MB2/MB1 ratio compared with normal volunteers (11, 14% vs. 1,1%, p = 0.003). Patients who deteriorated had higher MB2/MB1 ratio, (1.22 +/- 0.62 vs. 0.85 +/- 0.56; p = 0.01), and more frequently had abnormal MB2/ MB1 ratio (8, 30% vs. 3, 6%; p = 0.004) and CK and CK-MM activities (5, 19% vs. 2, 4%; p = 0.03) than those who remained stable. Patients with DCM with high CK-MB activity had 3.13-fold increased odds of sudden death or need for cardiac transplantation (95% confidence interval 1.53-6.40, p = 0.008). Thus, CK measurements, in particular CK-MB isoforms, are markers of myocardial damage in a subset of patients with DCM and could be useful in investigating the possibility of persistent myocardial damage in these patients.

Does rectus sheath infusion of bupivacaine reduce postoperative opioid requirement?

INTRODUCTION

The aim of this work was to assess the effect of intermittent bupivacaine infusion into rectus sheath space on postoperative opioid requirement, postoperative pain score and peak expiratory flow rate.

PATIENTS AND METHODS

A prospective, randomised study involving patients undergoing midline laparotomy. Patients were randomised to receive either intermittent infusion of bupivacaine 0.25% or normal saline via catheters placed in the rectus sheath for 48 h after operation. All patients received intravenous morphine infusion on demand with a patient-controlled analgesic device (PCAD).

RESULTS

Forty ASA I-III patients were studied. Nineteen were randomised to receive bupivacaine and 21 patients received normal saline. Patient characteristics and surgical variables were comparable in the two groups. The mean wound lengths were similar. There was no statistically significant difference in postoperative opioid requirement, postoperative pain score and peak expiratory flow rate between the two groups.

CONCLUSIONS

Intermittent bupivacaine infusion into the rectus sheath space after midline laparotomy does not reduce postoperative opioid requirement nor does it affect postoperative pain score or peak expiratory flow rate.

Prolonged function of macrophage, von Willebrand factor-deficient porcine pulmonary xenografts

Porcine von Willebrand factor (vWF) activates human and primate platelets. Having determined the importance of pulmonary intravascular macrophages (PIMs) in pulmonary xenotransplantation, we evaluated whether, in the absence of PIMs, vWF might play a role in pulmonary xenograft dysfunction. Utilizing a left single-lung transplant model, baboons depleted of anti-alphaGal antibodies received lungs from either vWF-deficient (n = 2); MCP-expressing (n = 5); MCP PIM-depleted (n = 5); or vWF-deficient PIM-depleted swine (n = 3). Two out of three of the PIM-depleted, pvWF deficient grafts survived longer than any previously reported pulmonary xenografts, including PIM-depleted xenografts expressing human complement regulatory proteins. Depletion of PIM's from vWF-deficient lungs, like depletion of PIM's from hMCP lungs, resulted in abrogation of the coagulopathy associated with pulmonary xenotransplantation. Thus, in terms of pulmonary graft survival, control of adverse reactions involving pvWF appears to be equally or even more important than is complement regulation using hMCP expression. However, based on the rapid failure of PIM-sufficient, pvWF-deficient pulmonary xenografts, pVWF-deficient pulmonary xenografts appear to be particularly sensitive to macrophage-mediated damage. These data provide initial evidence that vWF plays a role in the 'delayed' (24 h) dysfunction observed in pulmonary xenotransplantation using PIM depleted hMCP organs.

Characterization of Anti-Myosin Monoclonal Antibodies

The characterization of monoclonal antibodies (MAbs) with regard to reactivity and specificity is important for the successful application as a molecular probe and/or diagnostic reagent. Furthermore, it is recognized that some monoclonal reagents perform well in some assay systems but not others. In this study, the reactivity profiles of two anti-myosin MAbs (H1 and DH2, raised against human cardiac myosin) were evaluated in enzyme-linked immunosorbent assay (ELISA), slot-blotting, and immunocytochemistry. Both antibodies performed well in slot-blotting against myosin heavy chain preparations from cardiac and skeletal muscle and from non-human sources. In general, MAb H1 demonstrated strong to moderate reactivity in all assay systems, whilst MAb DH2 faired poorly in ELISA. MAb H1 also showed reactivity to synthetic peptides of myosin, one of which possessed a motif (ERRDA, single amino acid code) that was found in other human and nonhuman myosin protein sequences that could explain its cross-reactive profile. Intriguingly, this motif was found on viral and other pathogenic agents associated with myocarditis. Hence, it is speculated that this region could give some credence to the mechanism of molecular mimicry associated with some cardiac diseases. Overall, MAb H1 may serve as a useful probe of myosin structure.

The failing Fontan circulation: successful conversion of atriopulmonary connections

OBJECTIVES

Symptoms from low cardiac output or refractory atrial arrhythmias are complicating atriopulmonary (classical) Fontan connections. We present our experience of converting such patients to total cavopulmonary connections with and without arrhythmia surgery.

METHODS

Between 1997 and 2002, 15 patients (mean age, 19.7 +/- 7.0 years) underwent conversion operations 12.7 +/- 3.5 years after atriopulmonary Fontan operations. Preoperative New York Heart Association functional class was I in 2 patients, II in 2 patients, III in 6 patients, and IV in 5 patients. Four patients underwent intracardiac lateral tunnel conversion alone, and 11 received extracardiac total cavopulmonary connection, right atrial reduction, and cryoablation.

RESULTS

No mortality occurred. One patient had conduit obstruction in the immediate postoperative period requiring replacement, and another required a redo operation for endocarditis. Average hospitalization was 17.9 +/- 9.38 days; chest drains were removed on median day 4 (range, 1-29; mean, 7.4 +/- 7.58 days). At follow-up (mean, 42.6 +/- 22.1 months), late atrial arrhythmias had recurred in 3 of 4 patients with intracardiac total cavopulmonary connections (without ablation) and 1 of 11 patients with extracardiac total cavopulmonary connections with ablation. All patients are in New York Heart Association class I or II. Exercise ability (Bruce protocol) improved 69% from a mean of 6.18 +/- 4.01 minutes to 10.45 +/- 2.11 minutes (P <.05). Need for antiarrhythmic agents decreased postoperatively (patients receiving < or =1 antiarrhythmic: 9 preoperatively vs 15 at long-term follow-up, P <.05). No patient has required transplantation. Protein-losing enteropathy, which was present in 1 patient, improved transiently with conversion. There was 1 late death from gastrointestinal hemorrhage.

CONCLUSIONS

Fontan conversion can be achieved with low mortality and improvement in New York Heart Association class and exercise ability. Concomitant arrhythmia surgery reduces the incidence of late arrhythmias.

A porcine model of intimal-medial hyperplasia in polytetrafluoroethylene arteriovenous grafts

PURPOSE

Vascular access polytetrafluoroethylene (PTFE) graft failure is a major cause of morbidity in the hemodialysis population. The most common cause of graft failure is thrombosis secondary to stenosis at the venous outflow tract. Venous outflow stenosis is characterized by intimal-medial hyperplasia. We have developed a porcine arteriovenous (AV) graft model that may be used to investigate this proliferative response and aid in the development of new therapies to prevent intimal-medial hyperplasia and improve graft patency.

METHODS

Left carotid to right external jugular vein PTFE (6 mm) grafts were implanted in the necks of swine. Immediately following anatomosis, flow rates were recorded. In one group of animals (n = 4) the venous outflow tract was harvested after 7 days and morphometric analysis of intimal and medial area was performed. In a second group (n = 8) the graft patency was monitored until 28 days.

RESULTS

All porcine PTFE fistula grafts were patent at 7 days and 100% patency was maintained until 14 days. After 28 days, 75% of the grafts failed due to thrombosis. The venous outflow tract developed a significant proliferative response. After 7 days the intimal and medial areas were 469 +/- 9 microm2 and 875 +/- 26 microm2 respectively. At 28 days the intimal and medial areas were 913 +/- 55 microm2 and 1437 +/- 182 microm2 respectively. Luminal flow rate of the venous outflow tract was reduced significantly (344 +/- 11 ml/min at Day 0 to 129 +/- 14 ml/min at Day 7, p < 0.05).

CONCLUSIONS

This porcine model rapidly, reliably and robustly reproduces the flow reducing stenosis and intimal-medial hyperplasia at the venous outflow tract of PTFE arteriovenous fistula. It represents a promising tool for investigating the mechanisms of intimal-medial hyperplasia, evaluating therapeutic interventions and new graft materials.

The evaluation and physiologic assessment of hemorrhoidal disease: a review

The term hemorrhoids in generally used to describe "symptomatic hemorrhoids". A Medline review of the literature on anatomy, physiology and post-hemorrhoidectomy changes was performed and summarized in this review.

Comparison of the functional significance of left ventricular hypertrophy in hypertrophic cardiomyopathy and glycogenosis type III

A comparison of blood pressure response with exercise stress, thallium scintigraphy, and 24-hour electrocardiographic monitoring between 5 patients with left ventricular hypertrophy associated with glycogen storage disease type III and 10 matched patients with hypertrophic cardiomyopathy revealed normal results in the former group. These data highlight the importance of the etiology of left ventricular hypertrophy before the application of risk stratification.

Developmental expression, intracellular localization, and selenium content of the cysteine-rich protein associated with the mitochondrial capsules of mouse sperm

The outer membranes of mitochondria of mammalian sperm are encased in a keratinous structure known as the mitochondrial capsule. The experiments in the present study were designed to resolve a controversy surrounding the intracellular localization, developmental expression, and selenium-content of a cysteine-rich 17-20 kD protein that has been reported to constitute the major structural protein in the mitochondrial capsule of mammals. An antibody to a synthetic oligopeptide based on the predicted sequence of mouse cysteinerich protein recognizes a 24 kD protein in epididymal sperm tails of mice. The 24 kD protein does not appear to be a selenoprotein because: (1) it is not labeled with 75Se-selenite in seminiferous tubule culture; (2) cleavage with cyanogen bromide and translation of T7 RNA polymerase transcripts in vitro indicate that the translation start site is located downstream of potential UGA selenocysteine codons in the mouse cysteine-rich mRNA; (3) the reading frame encoding the cysteine-rich protein in rat lacks inphase UGA selenocysteine codons. Light and electron microscopy immunocytochemistry detects the cysteine-rich protein first during step 11 of spermiogenesis in the mouse demonstrating that the cysteine-rich protein mRNA is under temporal translational control. Electron microscope immunocytochemistry reveals that the cysteine-rich protein is evenly distributed in the cytoplasm in spermatids in steps 11 through early step 16 in mouse, and that it is associated with the outer mitochondrial membranes of spermatids in late step 16 and epididymal spermatozoa.