Transitioning disopyramide to mavacamten in obstructive hypertrophic cardiomyopathy: A case series and clinical guide

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a genetic disorder for which first-line treatments for obstructive HCM (oHCM) include beta-blockers, non-dihydropyridine calcium channel blockers, and disopyramide for refractory cases. Mavacamten, a selective cardiac myosin inhibitor, is indicated for symptomatic oHCM to improve functional capacity and symptoms. Use of disopyramide and mavacamten together is not recommended due to concerns of additive negative inotropic effects. Transitioning from disopyramide to mavacamten may be preferred to avoid adverse effects and frequent administration, however, the best approach for making the transition has not been established.

CASES

We present a series of seven patients with oHCM who transitioned from disopyramide to mavacamten and underwent echocardiograms mandated by a Risk Evaluation and Mitigations Strategies program. Two methods were employed. The first approach, involving washout of disopyramide before starting mavacamten, resulted in worsening of heart failure symptoms in the first two cases. The second approach, involving tapering disopyramide when starting mavacamten, was successfully implemented in the last five cases, with no adverse effects or worsening of systolic dysfunction.

CONCLUSION

Our method of tapering disopyramide when starting mavacamten using a stepwise approach is feasible and safe. Our report fulfills an unmet need by serving as a guide for other clinicians who seek to transition their patients from disopyramide to mavacamten.

Heart-liver-kidney transplantation for AL amyloidosis using normothermic recovery and storage from a donor following circulatory death: Short-term outcome in a first-in-world experience

AL amyloidosis is a rare condition characterized by the overproduction of an unstable free light chain, protein misfolding and aggregation, and extracellular deposition that can progress to multiorgan involvement and failure. To our knowledge, this is the first worldwide report to describe triple organ transplantation for AL amyloidosis and triple organ transplantation using thoracoabdominal normothermic regional perfusion recovery with a donation from a circulatory death (DCD) donor. The recipient was a 40-year-old man with multiorgan AL amyloidosis with a terminal prognosis without multiorgan transplantation. An appropriate DCD donor was selected for sequential heart, liver, and kidney transplants via our center's thoracoabdominal normothermic regional perfusion pathway. The liver was additionally placed on an ex vivo normothermic machine perfusion, and the kidney was maintained on hypothermic machine perfusion while awaiting implantation. The heart transplant was completed first (cold ischemic time [CIT]: 131 minutes), followed by the liver transplant (CIT: 87 minutes, normothermic machine perfusion: 301 minutes). Kidney transplantation was performed the following day (CIT: 1833 minutes). He is 8 months posttransplant without evidence of heart, liver, or kidney graft dysfunction or rejection. This case highlights the feasibility of normothermic recovery and storage modalities for DCD donors, which can expand transplant opportunities for allografts previously not considered for multiorgan transplantations.

Thin filament cardiomyopathies: A review of genetics, disease mechanisms, and emerging therapeutics

All muscle contraction occurs due to the cyclical interaction between sarcomeric thin and thick filament proteins within the myocyte. The thin filament consists of the proteins actin, tropomyosin, Troponin C, Troponin I, and Troponin T. Mutations in these proteins can result in various forms of cardiomyopathy, including hypertrophic, restrictive, and dilated phenotypes and account for as many as 30% of all cases of inherited cardiomyopathy. There is significant evidence that thin filament mutations contribute to dysregulation of Ca2+ within the sarcomere and may have a distinct pathomechanism of disease from cardiomyopathy associated with thick filament mutations. A number of distinct clinical findings appear to be correlated with thin-filament mutations: greater degrees of restrictive cardiomyopathy and relatively less left ventricular (LV) hypertrophy and LV outflow tract obstruction than that seen with thick filament mutations, increased morbidity associated with heart failure, increased arrhythmia burden and potentially higher mortality. Most therapies that improve outcomes in heart failure blunt the neurohormonal pathways involved in cardiac remodeling, while most therapies for hypertrophic cardiomyopathy involve use of negative inotropes to reduce LV hypertrophy or septal reduction therapies to reduce LV outflow tract obstruction. None of these therapies directly address the underlying sarcomeric dysfunction associated with thin-filament mutations. With mounting evidence that thin filament cardiomyopathies occur through a distinct mechanism, there is need for therapies targeting the unique, underlying mechanisms tailored for each patient depending on a given mutation.

HFSA Position Statement The Impact of Healthcare Disparities on Patients with Heart Failure

Heart Failure (HF) remains a condition associated with high morbidity, mortality, and associated costs. Although the number of medical and device-based therapies available to treat HF are expanding at a remarkable rate, disparities in the risk for incident HF and treatments delivered to patients are also of growing concern. These disparities span across racial and ethnic groups, socioeconomic status, and apply across the spectrum of HF from Stage A to Stage D. The complexity of HF risk and treatment is further impacted by the number of patients who experience the downstream impact of social determinants of health. The purpose of this document is to highlight the known healthcare disparities that exist in the care of patients with HF, and to provide a context for how clinicians and researchers should assess both biologic and social determinants of HF risk in vulnerable populations. Furthermore, this document will provide a framework for future steps that can be utilized to help diminish inequalities in access and clinical outcomes over time, and offer solutions to help reduce disparities within HF care.

Factors influencing transfusion-associated HLA sensitization in patients bridged to heart transplantation using ventricular assist device

BACKGROUND

Bridging heart failure patients with mechanical ventricular assist devices (VAD) enables access to transplantation. However, VAD is associated with increased risk for anti-HLA antibodies associated with rejection of subsequent allografts. Factors determining alloantibody formation in these patients remain undefined.

METHODS

We performed a single-center retrospective cohort study of 164 patients undergoing heart transplantation from 2014 to 2017. Medical records including use of VAD, transfused blood products, anti-HLA antibody testing, crossmatch, and time to transplant were evaluated.

RESULTS

Patients received an average of 13.8 red blood cell and 1.9 single-donor platelet units associated with VAD. There was a 28.7% increase in the incidence of anti-HLA antibodies after VAD. Development of anti-HLA antibodies did not correlate with volume or type of blood products, but with pre-VAD HLA sensitization status; relative risk of new alloantibodies in patients with pre-VAD antibodies was 3.5-fold higher than those without prior antibodies (P = .008). Development of new anti-HLA antibodies was associated with an increased time to transplant (169 vs 330 days, P = .013).

CONCLUSIONS

Our findings indicate that the presence of anti-HLA antibodies pre-VAD was the most significant risk factor for developing additional antibodies post-VAD, suggesting that a subset of patients may be predisposed to alloantibody formation.

Heart transplantation outcomes for rheumatic heart disease: Analysis of international registry data

BACKGROUND

Rheumatic heart disease (RHD), an autoimmune sequela of Group A streptococcal infection, is a chronic valvular disease affecting 32 million people worldwide, predominantly in developing nations. As the predisposition to autoimmune sequela still remains post transplantation, our primary objective was to assess if there were differences in mortality and rejection rates.

METHODS AND RESULTS

Using the International Society for Heart and Lung Transplantation (ISHLT) adult heart transplant registry, we identified 42 RHD patients who had undergone heart transplantation between 1988 and 2014. We matched the 42 RHD recipients by transplant year, age, and gender to 420 dilated cardiomyopathy (DCM) recipients. One-year mortality in the RHD group was 17.95% vs. 7.92% in the DCM group (P = 0.07). Survival was significantly reduced in the RHD group vs. the DCM group via Kaplan Meier curves (P = 0.04). In a multivariate model, RHD status (OR 3.19, 95% CI 1.15-8.83, P = 0.025) and serum creatinine (OR 1.41, 95% CI 1.09-1.82, P = 0.009) were associated with an increased odds of one-year mortality (P = 0.0013).

CONCLUSIONS

At one year post transplantation, RHD recipients had a significantly lower survival than DCM recipients. RHD status was also an independent predictor of mortality at 1 year post transplantation.

Detection and Management of Geographic Disparities in the TOPCAT Trial: Lessons Learned and Derivative Recommendations

TOPCAT (Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist Trial) was a multinational clinical trial of 3,445 heart failure with preserved ejection fraction patients that enrolled in 233 sites in 6 countries in North America, Eastern Europe, and South America. Patients with a heart failure hospitalization in the last 12 months or an elevated B-type natriuretic peptide were randomized to the mineralocorticoid receptor antagonist spironolactone versus placebo. Sites in Russia and the Republic of Georgia provided the majority of early enrollment, primarily based on the hospitalization criterion because B-type natriuretic peptide levels were initially unavailable there. With the emergence of country-specific aggregate event rate data indicating lower rates in Eastern Europe and differences in patient characteristics there, the Data Safety and Monitoring Board recommended relatively increasing enrollment in North America plus other corrective measures. Although final enrollment reflected the increased contribution from North America, a plurality of the final cohort came from Russia and Georgia (49% vs. 43% in North America). B-type natriuretic peptide measurements from Russia and Georgia, available later in the trial, suggested no or a mild level of heart failure consistent with low event rates. The primary results showed no significant spironolactone treatment effect overall (primary endpoint hazard ratio [HR]: 0.89; 95% confidence interval [CI]: 0.77 to 1.04), with a significant hazard ratio in North and South America (HR: 0.82; 95% CI: 0.69 to 0.98; p = 0.026) but not in Russia and Georgia (HR: 1.10; 95% CI: 0.79 to 1.51; interaction p = 0.12). This report describes the Data Safety and Monitoring Board’s detection and management recommendations for regional differences in patient characteristics in TOPCAT and suggests methods of surveillance and corrective actions that may be useful for future trials. (Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist Trial [TOPCAT]; NCT00094302)

Current Status of the Left Ventricular Assist Device as a Destination Therapy

The heart failure epidemic has led to an increase in the number of patients with advanced heart failure, which is associated with high morbidity and mortality. Current therapies for advanced heart failure are limited to heart transplantation and mechanical circulatory support, with palliative care reserved for those ineligible to receive advanced therapies. Clinical trials of ventricular assist devices for patients with advanced heart failure demonstrate an improvement in survival and quality of life akin to heart transplantation. The Achilles heal of this therapy is the adverse event burden. Patient selection and multidisciplinary care are two of the strategies being used to improve long-term outcomes. Adjunct therapies in combination with left ventricular assist device therapy and advances in device technology in the near future may lessen the number of adverse events. This review summarizes the clinical outcomes, current challenges and future directions of left ventricular assist device therapy.

Inotropic contractile reserve can risk-stratify patients with HIV cardiomyopathy: a dobutamine stress echocardiography study

OBJECTIVES

The purpose of this study was to assess whether inotropic contractile reserve (ICR) during dobutamine stress echocardiography (DSE) could risk-stratify patients with human immunodeficiency virus (HIV) cardiomyopathy and predict improvement of left ventricular ejection fraction (LVEF).

BACKGROUND

HIV cardiomyopathy is an important cause of heart failure and death. ICR is associated with better survival and improvement of LVEF in patients with ischemic and nonischemic cardiomyopathies. However, the prognostic value of ICR in patients with HIV cardiomyopathy is unknown.

METHODS

Patients with HIV cardiomyopathy and a LVEF <45% who were referred for DSE were enrolled. ICR was evaluated by the delta wall motion score index (ΔWMSI), calculated as the difference between rest and peak WMSI. Patients were followed for cardiac death and change in LVEF on follow-up.

RESULTS

Sixty patients (75% men; age, 54 ± 9 years) with HIV cardiomyopathy (mean LVEF, 28 ± 11%) formed the study group. After 2.4 ± 2.1 years, 11 cardiac deaths occurred (event rate of 7.6%/year). A receiver-operating characteristic curve identified a ΔWMSI of 0.38 as an optimal cut point for the presence of ICR, with a specificity of 88% and a sensitivity of 73% for the prediction of cardiac death. On univariable analysis, the absence of ICR (hazard ratio: 6.6; 95% confidence interval: 1.93 to 22.62; p = 0.003) and New York Heart Association functional class IV (hazard ratio: 7.2; 95% confidence interval: 2.20 to 23.65; p = 0.001) were the only predictors of cardiac death. After 2.1 ± 1.8 years, 41 patients had a follow-up echocardiogram. LVEF improvement from baseline occurred in 23 patients (56%), more so in patients with ICR than without ICR. A ΔWMSI of 0.59 predicted improvement in the LVEF with a specificity of 78% and a sensitivity of 74%.

CONCLUSIONS

The presence of ICR during DSE can risk-stratify and predict subsequent improvement in LVEF in patients with HIV cardiomyopathy.

Risk stratification and prognosis of human immunodeficiency virus-infected patients with known or suspected coronary artery disease referred for stress echocardiography

BACKGROUND

Patients with human immunodeficiency virus (HIV) infection are at increased risk of accelerated coronary artery disease (CAD) and cardiovascular events. Stress echocardiography (SE) is routinely used for risk stratification and prognosis of patients with known or suspected CAD. The prognostic value of SE in this high-risk group is unknown. The purpose of this study was to evaluate the prognostic value of SE in HIV-infected patients with known or suspected CAD.

METHODS AND RESULTS

We evaluated 311 patients (age, 52 ± 9 years; 74% men; left ventricular ejection fraction, 54 ± 12%) with history of HIV, undergoing SE (56% dobutamine). Left ventricular wall motion was evaluated on a 16-segment model, 5-point scale. An abnormal SE was defined by a fixed (infarction), biphasic, or new (ischemia) wall motion abnormality on stress. Follow-up for cardiac death and myocardial infarction was obtained. Seventy-nine (26%) patients had an abnormal SE. After 2.9 ± 1.9 years, 17 confirmed myocardial infarction and 14 cardiac deaths occurred. SE risk-stratified patients into normal versus abnormal subgroups (event rate, 0.6% per year versus 11.8% per year; P < 0.0001). Both abnormal SE (hazard ratio, 28.2; 95% confidence interval, 6.2 to 128.0; P < 0.0001) and the presence of any ischemia on SE (hazard ratio, 3.4; 95% confidence interval, 1.3 to 8.6; P = 0.009) were independent predictors of cardiac events. On a forward conditional Cox proportional hazards regression model, SE provided incremental prognostic value over clinical, stress ECG, and resting echocardiographic variables (global χ(2) increased from 17.8 to 24.5 to 65 to 109, P < 0.05 across all groups).

CONCLUSIONS

SE can effectively risk-stratify and prognosticate patients with HIV. The presence of ischemia and scar during SE provides independent and incremental prognostic value over traditional variables. A normal SE response portends a benign prognosis even in this high-risk subset.