Large animal models to study effectiveness of therapy devices in the treatment of heart failure with preserved ejection fraction (HFpEF)

Our understanding of the complex pathophysiology of Heart failure with preserved ejection fraction (HFpEF) is limited by the lack of a robust in vivo model. Existing in-vivo models attempt to reproduce the four main phenotypes of HFpEF; ageing, obesity, diabetes mellitus and hypertension. To date, there is no in vivo model that represents all the haemodynamic characteristics of HFpEF, and only a few have proven to be reliable for the preclinical evaluation of potentially new therapeutic targets. HFpEF accounts for 50% of all the heart failure cases and its incidence is on the rise, posing a huge economic burden on the health system. Patients with HFpEF have limited therapeutic options available. The inadequate effectiveness of current pharmaceutical therapeutics for HFpEF has prompted the development of device-based treatments that target the hemodynamic changes to reduce the symptoms of HFpEF. However, despite the potential of device-based solutions to treat HFpEF, most of these therapies are still in the developmental stage and a relevant HFpEF in vivo model will surely expedite their development process. This review article outlines the major limitations of the current large in-vivo models in use while discussing how these designs have helped in the development of therapy devices for the treatment of HFpEF.

Alterations in Coronary Blood Flow and the Risk of Left Ventricular Distension in Venoarterial Extracorporeal Membrane Oxygenation

Previous theoretical studies have suggested that veno-arterial extracorporeal membrane oxygenation (VA-ECMO) ought to consistently result in markedly increased left ventricular (LV) intracavitary pressures and volumes because of increased LV afterload. However, this phenomenon of LV distension does not universally occur and occurs only in a minority of cases. We sought to explain this discrepancy by considering the potential implications of VA-ECMO support on coronary blood flow and consequently improved LV contractility (the "Gregg" effect), in addition to the effects of VA-ECMO support upon LV loading conditions, in a lumped parameter-based theoretical circulatory model. We found that LV systolic dysfunction resulted in reduced coronary blood flow; VA-ECMO support augmented coronary blood flow proportionally to the circuit flow rate. On VA-ECMO support, a weak or absent Gregg effect resulted in increased LV end-diastolic pressures and volumes and increased end-systolic volume with decreased LV ejection fraction (LVEF), consistent with LV distension. In contrast, a more robust Gregg effect resulted in unaffected and/or even reduced LV end-diastolic pressure and volume, end-systolic volume, and unaffected or even increased LVEF. Left ventricular contractility augmentation proportional to coronary blood flow increased by VA-ECMO support may be an important contributory mechanism underlying why LV distension is observed only in a minority of cases.

Long-Term Outcomes of Allogeneic Hematopoietic Cell Transplantation in Patients with Newly Diagnosed Multiple Myeloma

Despite remarkable progress in survival with the availability of novel agents, an overwhelming majority of patients with multiple myeloma (MM) have disease that relapses. Allogeneic (allo-) hematopoietic cell transplantation (HCT) is a potentially curative option for a subgroup of patients with high-risk MM. This study assessed the long-term outcome of MM patients who underwent allo-HCT while in first remission as consolidation treatment. Thirty-three patients with newly diagnosed MM who underwent allo-HCT as part of consolidation therapy between 1994 and 2016 were reviewed retrospectively. Of these patients, 70% underwent autologous HCT before allo-HCT. All patients were chemosensitive and achieved at least partial response before proceeding to allo-HCT. Most received nonmyeloablative/reduced-intensity conditioning (88%) and a matched sibling donor graft (85%). Acute graft-versus-host disease (GVHD) and chronic GVHD occurred in 30% and 61% of patients, respectively. The median duration of follow-up was 64.1 months (range, 1.4 to 199.2 months) for all patients and 164.4 months (range, 56.0 to 199.2 months) for survivors. The median progression-free survival (PFS) was 36 months (95% confidence interval (CI), 8.6 to 73.0 months). The median time from treatment to progression was 73.0 months (95% CI, 30.6 months to not reached). The median overall survival (OS) was 131.9 months (95% CI, 38.4 months to not reached). Of all patients, 39% were alive for more than 10 years, with 46% (n = 6) without progression or relapse. The cumulative incidence of relapse was 18% at 1 year, 39% at 5 years, and 46% at 10 years post-allo-HCT. The cumulative incidence of nonrelapse mortality was 3% at 100 days, 18% at 1 year, 21% at 3 years, and 24% at 5 year post-allo-HCT. On multivariable analysis, high-risk cytogenetics were associated with a shorter PFS (hazard ratio [HR], 2.7; 95% CI, 1.01 to 7.21; P = .047) and OS (HR, 4.91; 95% CI, 1.48 to 16.27; P = .009). Achieving complete remission after allo-HCT also was associated with longer PFS (HR, 0.24; 95% CI, 0.09 to 0.64; P = .004) and OS (HR, .23; 95% CI, .07 to .72; P = .012). Allo-HCT may confer a survival advantage in a selected population of MM patients when performed early in the disease course; additional data on identifying the patients who will benefit the most are needed.

Device-Based Solutions to Improve Cardiac Physiology and Hemodynamics in Heart Failure With Preserved Ejection Fraction

Characterized by a rapidly increasing prevalence, elevated mortality and rehospitalization rates, and inadequacy of pharmaceutical therapies, heart failure with preserved ejection fraction (HFpEF) has motivated the widespread development of device-based solutions. HFpEF is a multifactorial disease of various etiologies and phenotypes, distinguished by diminished ventricular compliance, diastolic dysfunction, and symptoms of heart failure despite a normal ejection performance; these symptoms include pulmonary hypertension, limited cardiac reserve, autonomic imbalance, and exercise intolerance. Several types of atrial shunts, left ventricular expanders, stimulation-based therapies, and mechanical circulatory support devices are currently under development aiming to target one or more of these symptoms by addressing the associated mechanical or hemodynamic hallmarks. Although the majority of these solutions have shown promising results in clinical or preclinical studies, no device-based therapy has yet been approved for the treatment of patients with HFpEF. The purpose of this review is to discuss the rationale behind each of these devices and the findings from the initial testing phases, as well as the limitations and challenges associated with their clinical translation.

Multi-institutional Analysis of 200 COVID-19 Patients treated with ECMO:Outcomes and Trends

Background

The role of extracorporeal membrane oxygenation (ECMO) in the management of patients with COVID-19 continues to evolve. The purpose of this analysis is to review our multi-institutional clinical experience involving 200 consecutive patients at 29 hospitals with confirmed COVID-19 supported with ECMO.

Methods

This analysis includes our first 200 COVID-19 patients with complete data who were supported with and separated from ECMO. These patients were cannulated between March 17 and December 1, 2020. Differences by mortality group were assessed using χ² tests for categoric variables and Kruskal-Wallis rank sum tests and Welch’s analysis of variance for continuous variables.

Results

Median ECMO time was 15 days (interquartile range, 9 to 28). All 200 patients have separated from ECMO: 90 patients (45%) survived and 110 patients (55%) died. Survival with venovenous ECMO was 87 of 188 patients (46.3%), whereas survival with venoarterial ECMO was 3 of 12 patients (25%). Of 90 survivors, 77 have been discharged from the hospital and 13 remain hospitalized at the ECMO-providing hospital. Survivors had lower median age (47 versus 56 years, P < .001) and shorter median time from diagnosis to ECMO cannulation (8 versus 12 days, P = .003). For the 90 survivors, adjunctive therapies on ECMO included intravenous steroids (64), remdesivir (49), convalescent plasma (43), anti-interleukin-6 receptor blockers (39), prostaglandin (33), and hydroxychloroquine (22).

Conclusions

Extracorporeal membrane oxygenation facilitates survival of select critically ill patients with COVID-19. Survivors tend to be younger and have a shorter duration from diagnosis to cannulation. Substantial variation exists in drug treatment of COVID-19, but ECMO offers a reasonable rescue strategy.

Multi-institutional Analysis of 100 Consecutive Patients with COVID-19 and Severe Pulmonary Compromise Treated with Extracorporeal Membrane Oxygenation: Outcomes and Trends Over Time

The role of extracorporeal membrane oxygenation (ECMO) in the management of severely ill patients with coronavirus disease 2019 (COVID-19) continues to evolve. The purpose of this study is to review a multi-institutional clinical experience in 100 consecutive patients, at 20 hospitals, with confirmed COVID-19 supported with ECMO. This analysis includes our first 100 patients with complete data who had confirmed COVID-19 and were supported with ECMO. The first patient in the cohort was placed on ECMO on March 17, 2020. Differences by the mortality group were assessed using χ2 tests for categorical variables and Kruskal-Wallis rank-sum tests and Welch's analysis of variance for continuous variables. The median time on ECMO was 12.0 days (IQR = 8-22 days). All 100 patients have since been separated from ECMO: 50 patients survived and 50 patients died. The rate of survival with veno-venous ECMO was 49 of 96 patients (51%), whereas that with veno-arterial ECMO was 1 of 4 patients (25%). Of 50 survivors, 49 have been discharged from the hospital and 1 remains hospitalized at the ECMO-providing hospital. Survivors were generally younger, with a lower median age (47 versus 56.5 years, p = 0.014). In the 50 surviving patients, adjunctive therapies while on ECMO included intravenous steroids (26), anti-interleukin-6 receptor blockers (26), convalescent plasma (22), remdesivir (21), hydroxychloroquine (20), and prostaglandin (15). Extracorporeal membrane oxygenation may facilitate salvage and survival of selected critically ill patients with COVID-19. Survivors tend to be younger. Substantial variation exists in the drug treatment of COVID-19, but ECMO offers a reasonable rescue strategy.

Survival on the Heart Transplant Waiting List

Importance

With continuing improvements in medical devices and more than a decade since the 2006 United Network for Organ Sharing (UNOS) allocation policy, it is pertinent to assess survival among patients on the heart transplantation waiting list, especially given the recently approved 2018 UNOS allocation policy.

Objectives

To assess survival outcomes among patients on the heart transplant waiting list during the past 3 decades and to examine the association of ventricular assist devices (VADs) and the 2006 UNOS allocation policy with survival.

Design, Setting, and Participants

A retrospective cross-sectional used the UNOS database to perform an analysis of 95 323 candidates wait-listed for heart transplantation between January 1, 1987, and December 29, 2017. Candidates for all types of combined transplants were excluded (n = 2087). Patients were followed up from the time of listing to death, transplantation, or removal from the list due to clinical improvement. Competing-risk, Kaplan-Meier, and multivariable Cox proportional hazards regression analyses were used.

Main Outcomes and Measures

The analysis involved an unadjusted and adjusted survival analysis in which the primary outcome was death on the waiting list. Because of changing waiting list preferences and policies during the study period, the intrinsic risk of death for wait-listed candidates was assessed by individually analyzing, comparing, and adjusting for several candidate risk factors.

Results

In total, 95 323 candidates (72 915 men [76.5%]; mean [SD] age, 51.9 [12.0] years) were studied. In the setting of changes in listing preferences, 1-year survival on the waiting list increased from 34.1% in 1987-1990 to 67.8% in 2011-2017 (difference in proportions, 0.34%; 95% CI, 0.32%-0.36%; P < .001). The 1-year waiting list survival for candidates with VADs increased from 10.2% in 1996-2000 to 70.0% in 2011-2017 (difference in proportions, 0.60%; 95% CI, 0.58%-0.62%; P < .001). Similarly, in the setting of changing mechanical circulatory support indications, the 1-year waiting list survival for patients without VADs increased from 53.9% in 1996-2000 to 66.5% in 2011-2017 (difference in proportions, 0.13%; 95% CI, 0.12%-0.14%; P < .001). In the decade prior to the 2006 UNOS allocation policy, the 1-year waiting list survival was 51.1%, while in the decade after it was 63.9% (difference in proportions, 0.13%; 95% CI, 0.12%-0.14%; P < .001). In adjusted analysis, each time period after 1987-1990 had a marked decrease in waiting list mortality.

Conclusions and Relevance

This study found temporally associated increases in heart transplant waiting list survival for all patient groups (with or without VADs, UNOS status 1 and status 2 candidates, and candidates with poor functional status).

Trans-ventricular catheter device-based closure of postmyocardial infarction ventricular septal defect following coronary artery bypass grafting: A staged hybrid approach

A 66-year-old woman with a history of hypertension, ischemic stroke, and rheumatoid arthritis presented to the hospital with severe angina pectoris and dyspnea and was diagnosed with myocardial infarction (MI). Coronary angiography revealed multisystem coronary artery occlusive disease. Due to refractory myocardial ischemia/evolving MI, emergency coronary artery bypass grafting (CABG) was undertaken. Intraoperative transesophageal echocardiography additionally revealed an apical muscular ventricular septal defect (VSD). Concomitant VSD repair was deferred due to the absence of surface evidence of transmural MI for left ventriculotomy, in the setting of pre-existing severe left ventricular dysfunction. An initial totally percutaneous attempt to close the VSD postoperatively failed. A hybrid surgical/catheter-based VSD closure was performed on postoperative day 4, with a successful outcome. The patient did well postoperatively and currently is alive in good condition. To the best of our knowledge, this is the first report of a staged (post-CABG) and hybrid surgical/catheter-based technique without the utilization of cardiopulmonary bypass.

Towards the use of localised delivery strategies to counteract cancer therapy-induced cardiotoxicities

Cancer therapies have significantly improved cancer survival; however, these therapies can often result in undesired side effects to off target organs. Cardiac disease ranging from mild hypertension to heart failure can occur as a result of cancer therapies. This can warrant the discontinuation of cancer treatment in patients which can be detrimental, especially when the treatment is effective. There is an urgent need to mitigate cardiac disease that occurs as a result of cancer therapy. Delivery strategies such as the use of nanoparticles, hydrogels, and medical devices can be used to localise the treatment to the tumour and prevent off target side effects. This review summarises the advancements in localised delivery of anti-cancer therapies to tumours. It also examines the localised delivery of cardioprotectants to the heart for patients with systemic disease such as leukaemia where localised tumour delivery might not be an option.

Catching and killing of airborne SARS-CoV-2 to control spread of COVID-19 by a heated air disinfection system

Airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via air-conditioning systems poses a significant threat for the continued escalation of the current coronavirus disease (COVID-19) pandemic. Considering that SARS-CoV-2 cannot tolerate temperatures above 70 °C, here we designed and fabricated efficient filters based on heated nickel (Ni) foam to catch and kill SARS-CoV-2. Virus test results revealed that 99.8% of the aerosolized SARS-CoV-2 was caught and killed by a single pass through a novel Ni-foam-based filter when heated up to 200 °C. In addition, the same filter was also used to catch and kill 99.9% of Bacillus anthracis, an airborne spore. This study paves the way for preventing transmission of SARS-CoV-2 and other highly infectious airborne agents in closed environments.

Catching and killing of airborne SARS-CoV-2 to control spread of COVID-19 by a heated air disinfection system

Airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via air-conditioning systems poses a significant threat for the continued escalation of the current coronavirus disease (COVID-19) pandemic. Considering that SARS-CoV-2 cannot tolerate temperatures above 70 °C, here we designed and fabricated efficient filters based on heated nickel (Ni) foam to catch and kill SARS-CoV-2. Virus test results revealed that 99.8% of the aerosolized SARS-CoV-2 was caught and killed by a single pass through a novel Ni-foam-based filter when heated up to 200 °C. In addition, the same filter was also used to catch and kill 99.9% of Bacillus anthracis, an airborne spore. This study paves the way for preventing transmission of SARS-CoV-2 and other highly infectious airborne agents in closed environments.

Association of cardiovascular risk factor profile and financial hardship from medical bills among non-elderly adults in the United States

Background

While optimal cardiovascular risk factor (CRF) profile is associated with lower mortality, morbidity, and healthcare expenditures among individuals with atherosclerotic cardiovascular disease (ASCVD), less is known regarding its impact on financial hardship from medical bills. Therefore, we assessed whether an optimal CRF profile is associated with a lower burden of financial hardship from medical bills and a reduction in cost-related barriers to health.

Methods

We used a nationally representative sample of adults between 18 and 64 years from the National Health Interview Survey between 2013 and 2017. We assessed ASCVD status and the number of risk factors to categorize the study population into 4 mutually exclusive categories: ASCVD (irrespective of CRF profile) and non-ASCVD with poor, average, and optimal CRF profile. Adjusted logistic regression model was used to determine the association of ASCVD/CRF profile with financial hardship from medical bills and cost-related barriers to health (cost-related medication non-adherence (CRN), foregone/delayed care, and high financial distress).

Results

We included 119,388 non-elderly adults, representing 189 million individuals annually across the United States. Non-ASCVD/optimal CRF profile individuals had a lower prevalence of financial hardship and an inability paying medical bills when compared with individuals with ASCVD (24% vs 45% and 6% vs 19%, respectively). Among individuals without ASCVD and an optimal CRF profile, the prevalence of each cost-related barrier to health was <50% compared with individuals with ASCVD. Poor/low income and uninsured individuals within non-ASCVD/average CRF profile strata had a lower prevalence of financial hardship and an inability paying medical bills when compared with middle/high income and insured individuals with ASCVD. Non-ASCVD individuals with optimal CRF profile had the lowest odds of all barriers to health.

Conclusion

Optimal CRF profile is associated with a lower prevalence of financial hardship from medical bills and cost-related barriers to health despite lower income and lack of insurance.

Advanced Pulmonary and Cardiac Support of COVID-19 Patients: Emerging Recommendations From ASAIO-A "Living Working Document"

The severe acute respiratory syndrome (SARS)-CoV-2 is an emerging viral pathogen responsible for the global coronavirus disease 2019 (COVID)-19 pandemic resulting in significant human morbidity and mortality. Based on preliminary clinical reports, hypoxic respiratory failure complicated by acute respiratory distress syndrome is the leading cause of death. Further, septic shock, late-onset cardiac dysfunction, and multiorgan system failure are also described as contributors to overall mortality. Although extracorporeal membrane oxygenation and other modalities of mechanical cardiopulmonary support are increasingly being utilized in the treatment of respiratory and circulatory failure refractory to conventional management, their role and efficacy as support modalities in the present pandemic are unclear. We review the rapidly changing epidemiology, pathophysiology, emerging therapy, and clinical outcomes of COVID-19; and based on these data and previous experience with artificial cardiopulmonary support strategies, particularly in the setting of infectious diseases, provide consensus recommendations from ASAIO. Of note, this is a "living document," which will be updated periodically, as additional information and understanding emerges.

Advanced Pulmonary and Cardiac Support of COVID-19 Patients: Emerging Recommendations From ASAIO-a Living Working Document

The severe acute respiratory syndrome-CoV-2 is an emerging viral pathogen responsible for the global coronavirus disease 2019 pandemic resulting in significant human morbidity and mortality. Based on preliminary clinical reports, hypoxic respiratory failure complicated by acute respiratory distress syndrome is the leading cause of death. Further, septic shock, late-onset cardiac dysfunction, and multiorgan system failure are also described as contributors to overall mortality. Although extracorporeal membrane oxygenation and other modalities of mechanical cardiopulmonary support are increasingly being utilized in the treatment of respiratory and circulatory failure refractory to conventional management, their role and efficacy as support modalities in the present pandemic are unclear. We review the rapidly changing epidemiology, pathophysiology, emerging therapy, and clinical outcomes of coronavirus disease 2019; and based on these data and previous experience with artificial cardiopulmonary support strategies, particularly in the setting of infectious diseases, provide consensus recommendations from American Society for Artificial Internal Organs. Of note, this is a living document, which will be updated periodically, as additional information and understanding emerges.

Heterotopic Cardiac Transplantation: Long-term Results and Fate of the Native Heart

BACKGROUND

The long-term results of heterotopic cardiac transplantation have not been well defined. Patient survival rates and the fate of the native heart remain unclear.

METHODS

This study is a retrospective review of all 46 heterotopic cardiac transplantations performed at a single institution, the Texas Heart Institute in Houston, Texas, between 1982 and 2017. Four patients who underwent heterotopic transplantation as an emergency procedure for cardiogenic shock were excluded. Three of the procedures were repeat transplantations in patients who had previously undergone heterotopic transplantation; the 3 repeat transplantations were excluded, but the original procedures were not. Follow-up was 100% complete for mortality and 77% complete (30 of 39 patients) for assessment of preoperative indication for surgery and postoperative cardiac function.

RESULTS

For the 39 patients, the 1-year, 5-year, and 10-year survival rates were 69%, 36%, and 21%, respectively. One patient remains alive 25 years after the transplantation procedure. The most frequent indication for heterotopic transplantation was pulmonary vascular resistance greater than 4 Wood units (n = 11), followed by weight greater than 112.5 kg (n = 7). In most patients, native heart left ventricular ejection fraction stabilized over time to between 10% and 30%. Sinus rhythm was preserved in 87% (26 of 30) of native hearts at long-term follow-up.

CONCLUSIONS

Heterotopic cardiac transplantation is an acceptable procedure that should be considered for obese patients (especially those heavier than 112.5 kg) and patients with elevated pulmonary vascular resistance (especially those with pulmonary vascular resistance >4.0 Wood units). After heterotopic transplantation, native cardiac function appears to stabilize, and there is potential for native heart recovery.