Does Survival on the Heart Transplant Waiting List Depend on the Underlying Heart Disease?

Managing Heart Failure in Complex Adult Congenital Heart Disease

The management of complex congenital heart disease has advanced over the years. While certain complex congenital heart diseases are not compatible with life, palliative surgeries have developed to allow these children to survive into adulthood. Consequently, there are more children surviving into adulthood who have previously undergone complex palliative surgeries and have complex anatomy and physiology. There is a high prevalence of heart failure in adults with complex congenital heart disease due to its progressive nature. Often, anatomical and physiological sequelae of the disease itself or its surgical palliation lead to heart failure signs and symptoms over time. The nature of heart failure in this population is different than that of normal adults, and so management strategies must be adjusted based on the unique anatomy and physiology of these patients. While there are guidelines for monitoring and managing adults with complex congenital heart disease, there are limited data for medical therapies that improve symptom burden and mortality. Once these patients have worsening or decompensated heart failure, they often must be considered for advanced therapies, mechanical circulatory support, and transplant. There is still a need for further research and highly powered trials to elucidate how to optimally treat heart failure in adults with complex congenital heart disease.

Novel Therapies for Patients With Systemic Right Ventricle

Systemic RV dysfunction is a significant prognostic factor in congenital heart disease, particularly affecting patients with transposition of the great arteries post-atrial switch and congenitally corrected transposition of the great arteries. These patients often experience chronic pressure loading conditions, leading to structural, mechanical, and electrical adaptations that can result in heart failure. This article reviews novel therapeutic approaches for managing systemic right ventricular failure in patients with adult congenital heart disease, focusing on pharmacologic, device-based, and advanced heart failure therapies. Traditional heart failure medications such as angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, β-blockers, and mineralocorticoid receptor antagonists have shown mixed results in systemic right ventricular failure. However, newer agents like angiotensin receptor-neprilysin inhibitors and sodium-glucose cotransporter 2 inhibitors have demonstrated promising outcomes in improving cardiac remodeling and function. Cardiac resynchronization therapy has shown benefits in selected patients, particularly those with prior ventricular pacing. Mechanical circulatory support and heart transplantation remain viable options for advanced heart failure, with recent studies indicating favourable long-term outcomes. The management of systemic right ventricular failure requires a personalized approach, considering the unique anatomic and physiological characteristics of each patient. Although traditional therapies have limited efficacy, novel pharmacologic and device-based treatments might offer new hope for this patient population. Further research is needed to refine these strategies and identify new therapeutic targets.

Heart transplantation in adults with congenital heart diseases: A comprehensive meta-analysis on waiting times, operative, and survival outcomes

The rising prevalence of congenital heart disease (CHD) among adults has led to increased heart transplantation (HT) procedures in this population. However, CHD patients face significant challenges including longer waiting times, higher early mortality rates, and increased risks of complications such as renal dysfunction. This systematic review and meta-analysis examined 50 studies to assess waiting times, postoperative outcomes, and survival rates in CHD patients undergoing HT compared to non-CHD patients. Results revealed that CHD patients experience longer HT waiting times (mean difference [MD]: 53.86 days, 95 % CI: [22.00, 85.72], P = 0.0009) and increased ischemic times (MD: 20.01 min, 95 % CI: [10.51, 29.51], P < 0.0001), which may increase waitlist and early postoperative mortality. Regarding complications, renal dysfunction is more prevalent in CHD patients than in non-CHD patients (RR: 2.05, 95 % CI: [1.61, 2.61], P < 0.00001). Despite these challenges, long-term survival rates for CHD patients are comparable to those of non-CHD recipients, with significant improvements noted in recent allocation systems. Our findings emphasize the need for ongoing refinements in HT allocation systems to improve outcomes for CHD patients, particularly in reducing waiting times and managing post-transplant complications.

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

Impact of the New Heart Allocation System on the Medium-Term Outcomes in Patients With Hypertrophic Cardiomyopathy

The introduction of the new heart allocation system in the United States in 2018 resulted in an increase in the number of heart transplants (HT) performed among patients with hypertrophic cardiomyopathy (HCM). However, whether that affected medium-term post-HT outcomes in this group of patients remains unknown. We conducted an analysis of the United Network for Organ Sharing Transplant Database, including adults with HCM who underwent heart transplantation between 2015 and 2021. Patients were divided into two equal-duration eras: Era 1 (October 17, 2015, to October 17, 2018) and Era 2 (October 18, 2018, to October 18, 2021). In the studied period, 444 patients with HCM underwent HT: 204 in Era 1 and 240 in Era 2. In Era 2, the waitlist time was shorter, transplant rates were higher, patients were less frequently supported with inotropes but more often with an IABP, ischemic time was longer, and donor-to-recipient distance larger. Pre- and post-transplant functional status was comparable across the two eras, while the pre-HT employment rate was higher in the new system. The 3 year survival was unchanged across eras. In the new allocation system, despite more frequent mechanical circulatory support (MCS) use and increased ischemic time, the medium-term outcomes of patients with HCM remained favorable.

Assessing the Role of Primary Heart Failure Etiology on Cardiac Transplant Outcomes

BACKGROUND

There are diverse indications for heart transplantation (HTx), often categorized into ischemic (ICM) and nonischemic (NICM) cardiomyopathy. Although there is extensive research comparing the outcomes for these disease processes following certain therapeutic interventions, there are limited data on how recipient etiology impacts post-HTx survival. Our investigation seeks to identify this relationship.

METHODS

We conducted a retrospective analysis using adult HTx patients from the United Network for Organ Sharing database between 2000 and 2021. Patients with a combined heart-lung transplant or previous HTx were excluded. ICM included coronary artery disease (CAD) and ischemic dilated cardiomyopathy. NICM included nonischemic dilated (NIDCM), hypertrophic (HCM), and restrictive (RCM) cardiomyopathy. Overall survival was analyzed using Kaplan-Meier curves, log-rank tests, and multivariable Cox regression models.

RESULTS

A total of 42 268 patients were included in our study. Recipients with ICM were older and more likely to be males, obese, diabetics, and smokers. We found that patients with ICM had an increased incidence of transplant CAD (OR = 1.23, p < 0.001) and risk of mortality (hazard ratio [HR] = 1.22, p < 0.001) compared to NICM. When NICM was expanded, RCM had a similar hazard risk compared to ICM (HR = 1.03, p = 0.650), whereas both NIDCM (HR = 0.81, p < 0.001) and HCM (HR = 0.70, p < 0.001) had improved survival.

CONCLUSION

Our study provides evidence to suggest that ICM has decreased survival when compared to NICM. When NICM was expanded, RCM was found to have an increased mortality risk similar to ICM, whereas NIDCM and HCM both had superior outcomes. The clinical implication of this investigation will allow clinicians to better understand the prognosis of certain patient groups.

ECMO as a bridge to heart transplantation: Insights into stratification by heart failure etiology

Background

Revisions to the heart allocation criteria in 2018 motivated an increased use of extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation. Studies have demonstrated inferior post-transplant outcomes in patients bridged with ECMO but do not account for underlying diagnosis. Our objective was to elucidate the differential impact of ECMO on outcomes by heart failure (HF) etiology.

Methods

The United Network of Organ Sharing database was queried for adults who underwent isolated heart transplantation after October 2018. Patients were stratified by ECMO utilization at the time of transplantation and then by HF etiology. After baseline statistical comparisons, survival analysis relied on Kaplan-Meier estimates and Cox proportional models.

Results

A total of 13,203 patients were included, of whom 761 (5.8%) were supported with ECMO. ECMO patients were younger (48 vs 54 years, p < 0.001), less likely to have diabetes (24% vs 30%, p < 0.001), smoke cigarettes (31% vs 41%, p < 0.001), or have prior cardiac surgery (29% vs 36%, p < 0.001), more likely to require dialysis (20% vs 5%, p < 0.001), and spent fewer days on the waitlist (59 vs 190, p < 0.001). After adjustment, ECMO was associated with increased mortality (hazard ratio 1.85, p < 0.001) in the full cohort. After incorporating HF etiology, this increased mortality risk persisted in all subgroups except restrictive cardiomyopathy and congenital heart disease (CHD).

Conclusions

Our findings illustrate that HF etiology is associated with differing outcomes when bridging with ECMO. ECMO patients with restrictive cardiomyopathy or CHD did not have increased mortality risk. With ECMO utilization increasing, these data are hypothesis-generating and serve as a basis for further studies.

Impact of Heart Failure Etiology on Waitlist Mortality in Heart Transplant Candidates Supported With Extracorporeal Membrane Oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has gained traction as a bridge to heart transplantation (HT) but remains associated with increased waitlist mortality. This study explores whether this risk is modified by underlying heart failure (HF) etiology.

METHODS

Using the Organ Procurement and Transplantation Network registry, we conducted a retrospective review of first-time adult HT candidates from 2018 through 2022. Patients were categorized as "ECMO", if ECMO was utilized during the waitlisting period, or "No ECMO" otherwise. Patients were then stratified according to the following HF etiology: ischemic cardiomyopathy (CMP), dilated nonischemic CMP, restrictive CMP, hypertrophic CMP, and congenital heart disease (CHD). After baseline comparisons, waitlist mortality was characterized for ECMO and HF etiology using the Fine-Gray regression.

RESULTS

A total of 16 143 patients were identified of whom 7.0% (n = 1063) were bridged with ECMO. Compared to No ECMO patients, ECMO patients had shorter waitlist durations (46.3 vs. 185.0 days, p < 0.01) and were more likely to undergo transplantation (75.3% vs. 70.3%, p < 0.01). Outcomes analysis revealed that ECMO was associated with increased mortality risk (subdistribution hazard ratio [SHR]: 3.42, p < 0.01), a risk that persisted in all subgroups and was notably high in CHD (SHR: 4.83, p < 0.01) and hypertrophic CMP (SHR: 9.78, p < 0.01). HF etiology comparison within ECMO patients revealed increased mortality risk with CHD (SHR: 3.22, p < 0.01). Within No ECMO patients, hypertrophic CMP patients had lower mortality risk (SHR: 0.64, p = 0.03).

CONCLUSIONS

The increased waitlist mortality risk with ECMO persisted after stratification by HF etiology. These findings can help decision-making surrounding candidacy for cannulation and prognostic evaluation.

Failing with Cyanosis-Heart Failure in End-Stage Unrepaired or Partially Palliated Congenital Heart Disease

Heart failure in cyanotic congenital heart disease (CHD) is diagnosed clinically rather than relying solely on ventricular function assessments. Patients with cyanosis often present with clinical features indicative of heart failure. Although myocardial injury and dysfunction likely contribute to cyanotic CHD, the primary concern is the reduced delivery of oxygen to tissues. Symptoms such as fatigue, lassitude, dyspnea, headaches, myalgias, and a cold sensation underscore inadequate tissue oxygen delivery, forming the basis for defining heart failure in cyanotic CHD. Thus, it is pertinent to delve into the components of oxygen delivery in this context.

Prognosis after heart transplant in patients with hypertrophic and restrictive cardiomyopathy. A nationwide registry analysis

INTRODUCTION AND OBJECTIVES

Posttransplant outcomes among recipients with a diagnosis of hypertrophic cardiomyopathy (HCM) or restrictive cardiomyopathy (RCM) remain controversial.

METHODS

Retrospective analysis of a nationwide registry of first-time recipients undergoing isolated heart transplant between 1984 and 2021. One-year and 5-year mortality in recipients with HCM and RCM were compared with those with dilated cardiomyopathy (DCM).

RESULTS

We included 3703 patients (3112 DCM; 331 HCM; 260 RCM) with a median follow-up of 5.0 [3.1-5.0] years. Compared with DCM, the adjusted 1-year mortality risk was: HCM: HR, 1.38; 95%CI, 1.07-1.78; P=.01, RCM: HR, 1.48; 95%CI, 1.14-1.93; P=.003. The adjusted 5-year mortality risk was: HCM: HR, 1.17; 95%CI, 0.93-1.47; P=.18; RCM: HR, 1.52; 95%CI, 1.22-1.89; P<.001. Over the last 20 years, the RCM group showed significant improvement in 1-year survival (adjusted R2=0.95) and 5-year survival (R2=0.88); the HCM group showed enhanced the 5-year survival (R2=0.59), but the 1-year survival remained stable (R2=0.16).

CONCLUSIONS

Both RCM and HCM were linked to a less favorable early posttransplant prognosis compared with DCM. However, at the 5-year mark, this unfavorable difference was evident only for RCM. Notably, a substantial temporal enhancement in both early and late mortality was observed for RCM, while for HCM, this improvement was mainly evident in late mortality.

Waitlist Outcomes in Candidates With Rare Causes of Heart Failure After Implementation of the 2018 French Heart Allocation Scheme

BACKGROUND

In 2018, an algorithm-based allocation system for heart transplantation (HT) was implemented in France. Its effect on access to HT of patients with rare causes of heart failure (HF) has not been assessed.

METHODS

In this national study, including adults listed for HT between 2018 and 2020, we analyzed waitlist and posttransplant outcomes of candidates with rare causes of HF (restrictive cardiomyopathy [RCM], hypertrophic cardiomyopathy, and congenital heart disease). The primary end point was death on the waitlist or delisting for clinical deterioration. Secondary end points included access to HT and posttransplant mortality. The cumulative incidence of waitlist mortality estimated with competing risk analysis and incidence of transplantation were compared between diagnosis groups. The association of HF cause with outcomes was determined by Fine-Gray or Cox models.

RESULTS

Overall, 1604 candidates were listed for HT. At 1 year postlisting, 175 patients met the primary end point and 1040 underwent HT. Candidates listed for rare causes of HF significantly differed in baseline characteristics and had more frequent score exceptions compared with other cardiomyopathies (31.3%, 32.0%, 36.4%, and 16.7% for patients with hypertrophic cardiomyopathy, RCM, congenital heart disease, and other cardiomyopathies). The cumulative incidence of death on the waitlist and probability of HT were similar between diagnosis groups (P=0.17 and 0.40, respectively). The adjusted risk of death or delisting for clinical deterioration did not significantly differ between candidates with rare and common causes of HF (subdistribution hazard ratio (HR): hypertrophic cardiomyopathy, 0.51 [95% CI, 0.19-1.38]; P=0.18; RCM, 1.04 [95% CI, 0.42-2.58]; P=0.94; congenital heart disease, 1.82 [95% CI, 0.78-4.26]; P=0.17). Similarly, the access to HT did not significantly differ between causes of HF (hypertrophic cardiomyopathy: HR, 1.18 [95% CI, 0.92-1.51]; P=0.19; RCM: HR, 1.19 [95% CI, 0.90-1.58]; P=0.23; congenital heart disease: HR, 0.76 [95% CI, 0.53-1.09]; P=0.14). RCM was an independent risk factor for 1-year posttransplant mortality (HR, 2.12 [95% CI, 1.06-4.24]; P=0.03).

CONCLUSIONS

Our study shows equitable waitlist outcomes among HT candidates whatever the indication for transplantation with the new French allocation scheme.

Heart failure in systemic right ventricle: Mechanisms and therapeutic options

d-loop transposition of the great arteries (d-TGA) and congenitally corrected transposition of the great arteries (cc-TGA) feature a right ventricle attempting to sustain the systemic circulation. A systemic right ventricle (sRV) cannot support cardiac output in the long run, eventually decompensating and causing heart failure. The burden of d-TGA patients with previous atrial switch repair and cc-TGA patients with heart failure will only increase in the coming years due to the aging adult congenital heart disease population and improvements in the management of advanced heart failure. Clinical data still lags behind in developing evidence-based guidelines for risk stratification and management of sRV patients, and clinical trials for heart failure in these patients are underrepresented. Recent studies have provided foundational data for the commencement of robust clinical trials in d-TGA and cc-TGA patients. Further insights into the multifactorial nature of sRV failure can only be provided by the results of such studies. This review discusses the mechanisms of heart failure in sRV patients with biventricular circulation and how these mediators may be targeted clinically to alleviate sRV failure.

Impact of induction therapy on cytomegalovirus infection and post-transplant outcomes in pediatric heart transplant recipients receiving routine antiviral prophylaxis

OBJECTIVES

Induction therapy has been increasingly used in pediatric heart transplantation. This study evaluated the impact of anti-thymocyte globulin (ATG) versus basiliximab as induction therapy on post-transplant cytomegalovirus (CMV) infection, rejection at 1 year, coronary allograft vasculopathy (CAV), and mortality in pediatric heart transplant recipients receiving antiviral prophylaxis.

RESULTS

Of the 96 patients (age < 18 years) analyzed, 46 (47.9%) patients received basiliximab, and 50 (52.1%) received ATG. Median follow-up was 3.0 (IQR, 1.7-4.9) years with 32.3% reporting CMV infection. The ATG group, as compared with the basiliximab group, had similar incidences of CMV infection (36% vs. 28.3%, p = .418), CMV viremia (22% vs. 19.6%, p = .769), and CMV-positive tissue biopsy (30% vs. 22%, p = .486). The ATG group had lower incidences of rejection at 1 year (16% vs. 36.9%, p = .022) and CAV (4% vs. 23.9%, p = .006) with no difference in mortality (8% vs. 15.2%, p = .343), compared with the basiliximab group. Multivariate analysis showed that induction with ATG was associated with a lower risk of rejection at 1 year (OR, .31; 95% CI, .09-.94; p = .039) with no impact on the incidences of CMV infection (HR, 2.06; 95% CI, .54-7.89; p = .292), CAV (HR, .30; 95% CI, .04-2.58; p = .275), and mortality (HR, .39; 95% CI, .09-1.82; p = .233) compared to basiliximab induction.

DISCUSSION AND CONCLUSIONS

In conclusion, induction with ATG was associated with reduction in risk of rejection at 1 year with no effects on CMV infection, CAV, and mortality in pediatric heart transplant recipients with universal antiviral prophylaxis compared with basiliximab induction therapy.

Heart Failure in Complex Congenital Heart Disease of the Adult

PURPOSE OF REVIEW

Adult congenital heart disease (ACHD) patients have demonstrated improved survival, especially those with severely complex disease, mainly single-ventricle/Fontan physiology and those with a systemic right ventricle. We describe the heart failure phenotypes of complex CHD, reversible causes for heart failure, and considerations for advanced therapy.

RECENT FINDINGS

While initially marketed for application to patients with acquired causes for heart failure, newer devices and technologies have started to be used in the ACHD population. After reversible causes for heart failure in CHD are addressed, it is reasonable to consider use of new device-based technologies and orthotopic heart transplant (OHT) for end-stage disease. New heart failure technology and organ transplant should carefully be considered and applied in complex ACHD, where there may be significant improvement in morbidity and mortality.

Missed Opportunities in Identifying Cardiomyopathy Aetiology Prior to Advanced Heart Failure Therapy

BACKGROUND

Specific aetiologies of cardiomyopathy can significantly impact treatment options as well as appropriateness and prioritisation for advanced heart failure therapies such as ventricular assist device (VAD) or orthotopic heart transplantation (OHT). We reviewed the tissue diagnoses of patients who underwent advanced therapies for heart failure (HF) to identify diagnostic discrepancies.

METHODS

This study presents a retrospective cohort of the aetiology of cardiomyopathy in 118 patients receiving either durable VAD or OHT. Discrepancies between the preoperative aetiological diagnosis of cardiomyopathy with the pathological diagnosis were recorded. Echocardiographic and haemodynamic data were reviewed to examine differences in patients with differing aetiological diagnoses.

RESULTS

Twelve (12) of 118 (12/118) (10.2%) had a pathological diagnosis that was discordant with pre-surgical diagnosis. The most common missed diagnoses were infiltrative cardiomyopathy (5) and hypertrophic cardiomyopathy (3). Patients with misidentified aetiology of cardiomyopathy had smaller left ventricular (LV) dimensions on echocardiography than patients with dilated cardiomyopathy (5.8±0.9 vs 6.7±1.1 respectively p=0.01).

CONCLUSIONS

Most HF patients undergoing VAD and OHT had a correct diagnosis for their heart failure prior to treatment, but a missed diagnosis at time of intervention (VAD or OHT) was not uncommon. Smaller LV dimension on echocardiogram in a patient with a non-ischaemic cardiomyopathy warrants further workup for a more specific aetiology.

Expanding Selection Criteria to Repairable Diseased Hearts to Meet the Demand of Shortage of Donors in Heart Transplantation

Heart transplant surgery is considered the destination therapy for end-stage heart disease. Unfortunately, many patients in the United States of America who are eligible candidates for transplants cannot undergo surgery due to donor shortage. In addition, some donors' hearts are being labeled as unacceptable for transplant surgery because of the rigorous and restricted rules placed on the approval process of using a donor's heart. Over the last few decades, the rising discrepancy between the scarcity of donor hearts and the demand for such organs has led to the discussion of expanding the donor heart selection criteria. A softer view on using marginal hearts for transplants would help those on the waitlist to receive a heart transplant. Marginal hearts that contain the hepatitis c virus (HCV), COVID-19, older age, or repairable heart defects have become viable options to use for a heart transplant. Also, the prioritization based on the new heart allocation system would help efficiently decide which recipients would be the first to get a donor's heart. Recently there has been a consensus to broaden the eligibility of donor's hearts by accepting valvular abnormalities, coronary artery disease, and congenital abnormalities. This review highlights some of those expansions in selection criteria in particular using repairable hearts, which could be fixed in the operating room on the back table before transplantation.

Trends and Outcomes of Patients with Amyloid Cardiomyopathy Listed for Heart Transplantation

BACKGROUND

Heart transplantation in patients with amyloid cardiomyopathy (ACM) has been historically underutilized due to the risk of amyloid recurrence.

METHODS

Using data from the United Network for Organ Sharing database on patients listed for single-organ heart transplant between 2010 and 2019, we evaluated trend in heart transplant, and compared waitlist mortality and graft survival between patients with ACM and dilated cardiomyopathy (DCM). Also, we evaluated for independent predictors of outcomes.

RESULTS

Over the study period, 411 ACM adult patients with ACM were added to the heart transplant waitlist. In the propensity-matched cohorts, the rates of waitlist mortality was significantly higher for ACM compared to DCM (HR=1.75, 95%CI=1.16-2.65). Over the study period, 330 ACM patients underwent heart transplant. The number of transplants increased from 22 in 2010 to 59 in 2019 (168% increase). The 5-year graft survival rate was however significantly worse for ACM (78%) compared to DCM (82%) (HR=1.46, 1.03-2.08). We identified two predictors of graft failure among ACM patients, namely, renal failure requiring dialysis (HR=5.4, 1.6-17) and prior history of malignancy (HR=1.6, 1.0-28). ACM patients with neither of the risk factor had 5-year graft survival of 82% that is comparable to DCM (HR=1.28, 0.90-1.91). On the other hand, ACM patients with either of the risk factor had worse 5-year graft survival of 62% (HR=2.44, 1.39-4.28).

CONCLUSION

Increasing number of ACM patients are undergoing heart transplant. Although ACM patients experience higher waitlist mortality and worse graft survival compared to DCM, selecting carefully screened ACM patients may result in improved outcomes following heart transplant.

Computational Investigation of Anastomosis Options of a Right-Heart Pump to Patient Specific Pulmonary Arteries

Patients with Fontan circulation have increased risk of heart failure, but are not always candidates for heart transplant, leading to the development of the subpulmonic Penn State Fontan Circulation Assist Device. The aim of this study was to use patient-specific computational fluid dynamics simulations to evaluate anastomosis options for implanting this device. Simulations were performed of the pre-surgical anatomy as well as four surgical options: a T-junction and three Y-grafts. Cases were evaluated based on several fluid-dynamic quantities. The impact of imbalanced left-right pulmonary flow distribution was also investigated. Results showed that a 12-mm Y-graft was the most energy efficient. However, an 8-mm graft showed more favorable wall shear stress distribution, indicating lower risk of thrombosis and endothelial damage. The 8-mm Y-grafts also showed a more balanced pulmonary flow split, and lower residence time, also indicating lower thrombosis risk. The relative performance of the surgical options was largely unchanged whether or not the pulmonary vascular resistance remained imbalanced post-implantation.

Impact of the new UNOS donor heart allocation system on waitlist outcomes and early posttransplant mortality among adults with congenital heart disease

Adults with congenital heart disease (ACHD) experience worse waitlist outcomes and higher early posttransplant mortality compared to non-ACHD patients. On October 18, 2018; the UNOS donor heart allocation system was redesigned giving unique listing status to ACHD patients. The impact of this change on outcomes in transplant-listed patients is unstudied. Using the Scientific Registry of Transplant Recipients (SRTR) we compared ACHD patients listed for the first-time for heart transplantation from two eras of equal duration. We analyzed waitlist outcomes, posttransplant mortality and length of stay among ACHD patients in both eras and between ACHD and non-ACHD patients in the new era. Of 12 723 listed patients, 535 had ACHD (293 in the new era) and 12 188 did not (6258 in the new era). A total of 163 (56%) ACHD patients in the new era versus 150 (62%) in the prior era were transplanted; 11 (3.8%) versus 15 (6.2%) died on the waitlist; 32 (11%) versus 35 (14%) were delisted and 15 (9.2%) versus 19 (12.7%) died within 30 days of transplant, respectively. The new UNOS donor heart allocation system improved waitlist time and decreased the proportion not transplanted during the first 300 days after listing among ACHD patients without altering early posttransplant outcomes or significantly changing the gap in outcomes compared to non-ACHD patients.

Oxidative Stress Markers and Modified Model for End-Stage Liver Disease Are Associated with Outcomes in Patients with Advanced Heart Failure Receiving Bridged Therapy with Continuous-Flow Left Ventricular Assist Devices

Left ventricular assist device (LVAD) is well established as an alternative treatment for end-stage heart failure (HF) patients. The aim of the study was to determine the prognostic value of oxidative stress markers and the modified Model for End-Stage Liver Disease (modMELD) in patients receiving bridged therapy with continuous-flow LVAD. We prospectively analyzed 36 end-stage HF patients who received LVAD therapy between 2015 and 2018. The total antioxidant capacity (TAC) and total oxidant status (TOS) were measured by the methods described by Erel. The oxidative stress index (OSI) was defined as the ratio of the TOS to TAC levels. The modMELD scores were calculated based on the serum bilirubin, creatinine, and albumin levels. The patients’ median age was 58 (50–63.0) years. During the 1.5-years follow-up, a major adverse cardiac event—MACE (death, stroke, or pump thrombosis) was observed in 17 patients (47.2%). The area under the receiver operating characteristics curves (AUCs) indicated a good prognostic power of TAC (AUC 0.7183 (0.5417–0.8948)), TOS (AUC 0.9149 (0.8205–0.9298)), OSI (AUC 0.9628 (0.9030–0.9821)), and modMELD (AUC 0.87 (0.7494–0.9905)) to predict a MACE. Oxidative stress markers serum concentrations, as well as the modMELD score, allow the identification of patients with a risk of MACE.

Disparities in heart and lung transplantation

PURPOSE OF REVIEW

Cardiothoracic transplantation is the definitive therapy for end-stage heart and lung disease. In service to this population, disparities in access and care must be simultaneously understood and addressed.

RECENT FINDINGS

There are sex, race, geographic, age, and underlying disease disparities in both heart and lung transplantation. Women have reduced waitlist survival but improved posttransplant survival when compared with men for both heart and lung transplantation. Black patients have worse outcome compared with other races postheart transplant. Geographic disparities impact the likelihood of receiving heart or lung transplant and the growing number of patients with advanced age seeking transplant complicates discussions on survival benefit. Finally, underlying disease has affected outcomes for both heart and lung transplant and now are incorporated into the allocation system.

SUMMARY

Though heart and lung transplantation have several existing disparities, it remains to be seen how advancements in medical technology, changes in donor organ allocation policies, and growing experience in patient selection will impact these concerns.

Impact of the new heart allocation policy on patients with restrictive, hypertrophic, or congenital cardiomyopathies

Background

Patients with restrictive or hypertrophic cardiomyopathy (RCM/HCM) and congenital heart disease (CHD) do not derive clinical benefit from inotropes and mechanical circulatory support. Concerns were expressed that the new heart allocation system implemented in October 2018 would disadvantage these patients. This paper aimed to examine the impact of the new adult heart allocation system on transplantation and outcomes among patients with RCM/HCM/CHD.

Methods

We identified adult patients with RCM/HCM/CHD in the United Network for Organ Sharing (UNOS) database who were listed for or received a cardiac transplant from April 2017-June 2020. The cohort was separated into those listed before and after allocation system changes. Demographics and recipient characteristics, donor characteristics, waitlist survival, and post-transplantation outcomes were analyzed.

Results

The number of patients listed for RCM/HCM/CHD increased after the allocation system change from 429 to 517. Prior to the change, the majority RCM/HCM/CHD patients were Status 1A at time of transplantation; afterwards, most were Status 2. Wait times decreased significantly for all: RCM (41 days vs 27 days; P<0.05), HCM (55 days vs 38 days; P<0.05), CHD (81 days vs 49 days; P<0.05). Distance traveled increased for all: RCM (76 mi. vs 261 mi, P<0.001), HCM (88 mi. vs 231 mi. P<0.001), CHD (114 mi vs 199 mi, P<0.05). Rates of transplantation were higher for RCM and CHD (P<0.01), whereas post-transplant survival remained unchanged.

Conclusions

The new allocation system has had a positive impact on time to transplantation of patients with RCM, HCM, and CHD without negatively influencing survival.

Changes in heart transplant waitlist and posttransplant outcomes in patients with restrictive and hypertrophic cardiomyopathy with the new heart transplant allocation system

Historically, patients with restrictive (RCM) and hypertrophic cardiomyopathy (HCM) experienced longer wait-times for heart transplant (HT) and increased waitlist mortality. Recently, a new HT allocation system was implemented in the United States. We sought to determine the impact of the new HT system on RCM/HCM patients. Adult patients with RCM/HCM listed for HT between November 2015 and September 2019 were identified from the UNOS database. Patients were stratified into two groups: old system and new system. We identified 872 patients who met inclusion criteria. Of these, 608 and 264 were classified in the old and new system groups, respectively. The time in the waitlist was shorter (25 vs. 54 days, P < .001), with an increased frequency of HT in the new system (74% vs. 68%, P = .024). Patients who were transplanted in the new system had a longer ischemic time, increased use of temporary mechanical circulatory support and mechanical ventilation. There was no difference in posttransplant survival at 9 months (91.1% vs. 88.9%) (p = .4). We conclude that patients with RCM/HCM have benefited from the new HT allocation system, with increased access to HT without affecting short-term posttransplant survival.

Heart transplantation candidacy

PURPOSE OF REVIEW

Timely referral of eligible candidates for consideration of advanced therapies, such as a heart transplantation or mechanical circulatory support is essential. The characteristics of heart transplantation candidates have changed significantly over the years, leading to a more complex evaluation process. The present review summarizes recent advances in the evaluation process for heart transplantation eligibility.

RECENT FINDINGS

The heart transplantation allocation policy was recently reviewed in the USA in an effort to reduce waitlist mortality and to ensure fair geographic allocation of organs to the sickest patients. Moreover, patients with chronic infectious diseases, as well as malignancies, are being currently considered acceptable candidates for transplantation. Listing practices for heart transplantation vary between programmes, with a greater willingness to consider high-risk candidates at higher-volume centres.

SUMMARY

The ultimate decision to place high-risk candidates on the heart transplantation waitlist should be based on a combination of quantitative and qualitative data analysis informed by clinical judgement, and the chronic shortage of organ donors makes this process an important ethical concern for any society. Future guidelines should discuss approaches to achieve fair organ allocation while preserving improved outcomes after transplantation.

Expanding Heart Transplant in the Era of Direct-Acting Antiviral Therapy for Hepatitis C

Importance

For patients awaiting heart transplant, hepatitis C-positive donors offer an opportunity to expand the donor pool, shorten wait times, and decrease wait-list mortality. While early reported outcomes among few heart transplant recipients have been promising, knowledge of 1-year outcomes in larger cohorts of patients is critical to shared decision-making with patients about this option.

Objective

To better define the association of hepatitis C-positive donors with heart transplant volumes, wait-list duration, the transmission and cure of donor-derived hepatitis C, and morbidity and mortality at 1 year.

Design, Setting, and Participants

This was a prospective, single-center observational study of 80 adult (age 18 years or older) patients who underwent heart transplant using hearts from hepatitis C-positive donors between September 2016 and April 2019 at a large academic medical center. Among donors, who were considered hepatitis C-positive if results from hepatitis C antibody and/or nucleic acid testing were positive, 70 had viremia and 10 were seropositive but did not have viremia. Follow-up was available through May 15, 2019. Comparisons were drawn with patients who underwent transplant with hearts from hepatitis C-negative donors during the same period.

Exposures

In addition to standard posttransplant management, transplant recipients who developed donor-derived hepatitis C infection were treated with direct-acting antivirals.

Main Outcomes and Measures

The main outcomes included wait-list duration and 1-year survival in all patients, and for those who developed donor-derived hepatitis C, the response to direct-acting antiviral treatment.

Results

Of 80 patients, 57 (71.3%) were men, 55 (68.7%) were white, and 17 (26.3%) were black; the median age at transplant was 54.5 years (interquartile range, 46-62 years). Following consent to accept hearts from hepatitis C-exposed donors, the median days to heart transplant was 4 (interquartile range, 1-18). No recipients of donors with negative nucleic acid testing results (10 [12.5%]) developed donor-derived hepatitis C. Of 70 patients who were recipients of donors with positive nucleic acid testing results, 67 (95.7%) developed donor-derived hepatitis C over a median follow-up of 301 days (interquartile range, 142-617). Treatment with direct-acting antivirals was well tolerated and yielded sustained virologic responses in all treated patients. Within the cohort with infection, 1-year patient survival was 90.4%, which was not significantly different compared with the cohort without infection or with patients who received transplants from hepatitis C-negative donors during the same period.

Conclusions and Relevance

In the era of direct-acting antivirals, hepatitis C-positive donors are a viable option to expand the donor pool, potentially reducing wait-list duration and mortality. In heart transplant recipients with donor-derived hepatitis C, infection is well-tolerated and curable, and 1-year survival is equivalent to that in recipients of hepatitis C-negative donors.

Comparing outcomes for infiltrative and restrictive cardiomyopathies under the new heart transplant allocation system

The new heart transplantation (HT) allocation policy was introduced on 10/18/2018. Using the UNOS registry, we examined early outcomes following HT for restrictive cardiomyopathy, hypertrophic cardiomyopathy, cardiac sarcoidosis, or cardiac amyloidosis compared to the old system. Those listed who had an event (transplant, death, or waitlist removal) prior to 10/17/2018 were in Era 1, and those listed on or after 10/18/2018 were in Era 2. The primary endpoint was death on the waitlist or delisting due to clinical deterioration. A total of 1232 HT candidates were included, 855 (69.4%) in Era 1 and 377 (30.6%) in Era 2. In Era 2, there was a significant increase in the use of temporary mechanical circulatory support and a reduction in the primary endpoint, (20.9 events per 100 PY (Era 1) vs. 18.6 events per 100 PY (Era 2), OR 1.98, p = .005). Median waitlist time decreased (91 vs. 58 days, p < .001), and transplantation rate increased (119.0 to 204.7 transplants/100 PY for Era 1 vs Era 2). Under the new policy, there has been a decrease in waitlist time and waitlist mortality/delisting due to clinical deterioration, and an increase in transplantation rates for patients with infiltrative, hypertrophic, and restrictive cardiomyopathies without any effect on post-transplant 6-month survival.

Canadian Cardiovascular Society/Canadian Cardiac Transplant Network Position Statement on Heart Transplantation: Patient Eligibility, Selection, and Post-Transplantation Care

Significant practice-changing developments have occurred in the care of heart transplantation candidates and recipients over the past decade. This Canadian Cardiovascular Society/Canadian Cardiac Transplant Network Position Statement provides evidence-based, expert panel recommendations with values and preferences, and practical tips on: (1) patient selection criteria; (2) selected patient populations; and (3) post transplantation surveillance. The recommendations were developed through systematic review of the literature and using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The evolving areas of importance addressed include transplant recipient age, frailty assessment, pulmonary hypertension evaluation, cannabis use, combined heart and other solid organ transplantation, adult congenital heart disease, cardiac amyloidosis, high sensitization, and post-transplantation management of antibodies to human leukocyte antigen, rejection, cardiac allograft vasculopathy, and long-term noncardiac care. Attention is also given to Canadian-specific management strategies including the prioritization of highly sensitized transplant candidates (status 4S) and heart organ allocation algorithms. The focus topics in this position statement highlight the increased complexity of patients who undergo evaluation for heart transplantation as well as improved patient selection, and advances in post-transplantation management and surveillance that have led to better long-term outcomes for heart transplant recipients.

[Features of the clinical picture and outcomes in patients from a heart transplantation waiting list with different causes of heart failure]

Aim To identify clinical differences between patients on the heart transplant waiting list (HTWL) in the origin of chronic heart failure (CHF).Materials and methods From January 2010 through September 2019, 235 patients (age, 47+13 years (from 10 to 67 years); men, 79% (n=186)) were included in the HTWL. The patients were divided into two groups; group 1 (n=104, 44 %) consisted of patients with ischemic heart disease (IHD); group 2 (n=131, 56 %) included patients with noncoronarogenic CHF. Clinical and instrumental data and frequency of the mechanical circulatory support (MCS) as a "bridge" to heart transplantation (HT) were retrospectively evaluated.Results Group 1 included more male patients than group 2 [97 % (n=101) and 82 % (n=85), р&lt;0.0001]; patients were older (54±8 and 42±14 years, р=0.0001). On inclusion into the HTWL, the CHF functional class was comparable in the groups, III [III;IV]; there were more patients of the UNOS 2 class in group 1 than in group 2 [75 % (n=78) and 57 % (n=75), р=0.005]. Patient distribution in UNOS 1B and 1A classes was comparable in the groups: 21% (n=22) and 3% (n=4) in group 1 and 33 % (n=43) and 10 % (n=13) in group 2. According to echocardiography patients of group 1 compared to group 2 showed a tendency towards higher values of left ventricular ejection fraction (Simpson method) [22 [18;26] % and 19 [15;24] %, р=0.37] and stroke volume [59 [44;72] % and 50 [36;67] %, р=0.07]. Numbers of patients with a cardioverter defibrillator or a cardiac resynchronization device with a defibrillator function were comparable in the groups [35 % (n=36) and 34 % (n=45)]. Comparison of comorbidities in groups 1 and 2 showed higher incidences of pulmonary hypertension [55 % (n=57) and 36 % (n=47), р=0.005], obesity [20 % (n=21) and 10 % (n=13), р=0.03], and type 2 diabetes mellitus [29 % (n=30) and 10 % (n=13), р=0.0004]. Rates of chronic obstructive lung disease, stroke, chronic kidney disease and other diseases were comparable. Duration of staying on the HTWL was comparable (104 [34; 179] and 108 [37; 229] days). During staying on the HTWL, patients of group 1 less frequently required MCS implantation [3 % (n=3) and 28 % (n=21), р=0.0009]. HT was performed for 59 % patients (n=61) in group 2 and 52 % (n=69) patients in group 2. Death rate in the HTWL was lower in group 1 [13 % (n=14) and 27 % (n=35), р&lt;0.01].Conclusion On inclusion into the HTWL, patients with noncoronarogenic CHF had more pronounced CHF manifestations and a more severe UNOS class but fewer comorbidities than patients with CHF of ischemic origin. With a comparable duration of waiting for HT, patients with noncoronarogenic CHD more frequently required MCS implantation and had a higher death rate.

Prognosis of heart transplant patients in Mashhad University of Medical Sciences

Introduction

Heart transplant is the ultimate treatment for patients with end-stage heart failure.

Aim

To assess 50 heart transplant patients for underlying diseases, transplantation outcome and mortality rate during a 5-year follow-up program.

Material and methods

Fifty heart transplant patients who underwent heart transplantation from 2012 to 2017 were assessed for underlying diseases, organ rejection, duration of hospitalization, extubation time, cardiac output and survival. Biopsy samples were obtained after surgery for evaluation of rejection.

Results

Dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) were the most common underlying diseases with prevalence of 56% and 12%, respectively. Significant improvement in ejection fraction was observed following heart transplant. Minimum and maximum extubation and hospitalization times were 3–408 hours and 1–51 days, respectively. Organ rejection evaluation 10 days after heart transplantation revealed that 50% of patients did not show any rejection while 10% had severe rejection. At 30 days post-operatively the number of patients with grade III rejection decreased to 2% while 56% of patients had no sign of rejection. The 5-year survival rate was 66% while infection and arrhythmia were the most common causes of death.

Conclusions

DCM and ICM are considered the most prevalent underlying diseases in heart transplant candidates. Ejection fraction reached normal ranges following transplant, which provides good quality of life. Low incidence of severe acute rejection demonstrates the effectiveness of our immunosuppressive therapy. In the cases of increased rejection, the patient’s immunosuppressive regimen was re-assessed accordingly.

Transplant and mechanical circulatory support in patients with adult congenital heart disease

Advances in surgery and pediatric care over the past decades have achieved improved survival for children born with congenital heart disease (CHD) and have produced a large, growing population of patients with adult congenital heart disease (ACHD). Heart failure has emerged as the leading cause of death and a major cause of morbidity among the ACHD population, while as little evidence supports the efficacy of guideline-directed medical therapies in this population. It is increasingly important that clinicians caring for these patients understand how to utilize mechanical circulatory support (MCS) in ACHD. In this review, we summarize the data on transplantation and MCS in the ACHD-heart failure population and provide a framework for how ACHD patients may benefit from advanced heart failure therapies like transplantation and MCS.

A novel risk score to predict survival in advanced heart failure due to cardiac amyloidosis

BACKGROUND

Cardiac amyloidosis, caused by deposition of immunoglobulin light chains (AL) or transthyretin (ATTR), carries a poor prognosis. Established risk scores for amyloidosis may not predict outcomes in those patients who develop advanced heart failure and who are potential candidates for heart transplantation. Here, we aimed to identify predictive parameters for patients with severe heart failure due to amyloidosis.

METHODS

Out of > 1000 patients with cardiac amyloidosis (AL or ATTR) admitted to our centre between September 1998 and January 2016, a cohort of 120 patients with a complete cardiac assessment at diagnosis, including right heart catheterization, echocardiography and biomarkers, was analysed retrospectively in this study. Primary endpoint was all-cause mortality. We performed univariate and multivariate Cox regression analysis, generated risk scores to predict outcomes in AL and ATTR amyloidosis and compared those to established risk models for amyloidosis.

RESULTS

In the Cox multivariate model, high-sensitivity troponin T (hsTnT; hazard ratio (HR) 1.003; confidence interval (CI) 1.001-1.005; p = 0.009) and mean pulmonary artery pressure (HR 1.061; CI 1.024-1.100; p = 0.001) were found to significantly and independently predict outcomes for AL amyloidosis, whereas QRS duration (HR 1.021; CI 1.004-1.039; p = 0.013), hsTnT (HR 1.021; CI 1.006-1.036; p = 0.006) and N-terminal pro-brain natriuretic peptide (HR 1.0003; CI 1.0001-1.0004; p = 0.002) were the best predictors for ATTR amyloidosis. A simple risk score ("HeiRisk") including these parameters for AL and ATTR allowed a more precise risk stratification in our patient population compared to established risk models.

CONCLUSIONS

Risk stratification for cardiac amyloidosis with the newly developed "HeiRisk" score may be superior to other staging systems for patients with advanced heart failure due to amyloid cardiomyopathy.

Mechanical Circulatory Support Device Utilization and Heart Transplant Waitlist Outcomes in Patients With Restrictive and Hypertrophic Cardiomyopathy

BACKGROUND

Patients with restrictive cardiomyopathy (RCM) and hypertrophic cardiomyopathy (HCM) generally are considered poor candidates for mechanical circulatory support devices (MCSDs) and often not able to be bridged mechanically to heart transplantation. This study characterized MCSD utilization and transplant waitlist outcomes in patients with RCM/HCM under the current allocation system and discusses changes in the era of the new donor allocation system.

METHODS AND RESULTS

Patients waitlisted from 2006 to 2016 in the United Network for Organ Sharing registry were stratified by RCM/HCM versus other diagnoses. MCSD utilization and waitlist duration were analyzed by propensity score models. Waitlist outcomes were assessed by cumulative incidence functions with competing events. Predictors of waitlist mortality or delisting for worsening status in patients with RCM/HCM were identified by proportional hazards model. Of 30 608 patients on the waitlist, 5.1% had RCM/HCM. Patients with RCM/HCM had 31 fewer waitlist days (P<0.01) and were ≈26% less likely to receive MCSD (P<0.01). Cumulative incidence of waitlist mortality was similar between cohorts; however, patients with RCM/HCM had higher incidence of heart transplantation. Predictors of waitlist mortality or delisting for worsening status in patients with RCM/HCM without MCSD support included estimated glomerular filtration rate <60 mL/min per 1.73 m², pulmonary capillary wedge pressure >20 mm Hg, inotrope use, and subjective frailty.

CONCLUSIONS

Patients with RCM/HCM are less likely to receive MCSD but have similar waitlist mortality and slightly higher incidence of transplantation compared with other patients. The United Network for Organ Sharing RCM/HCM risk model can help identify patients who are at high risk for clinical deterioration and in need of expedited heart transplantation.

Apical myectomy for patients with hypertrophic cardiomyopathy and advanced heart failure

OBJECTIVE

In patients with apical hypertrophic cardiomyopathy, extensive apical hypertrophy may reduce left ventricular end-diastolic volume and contribute to diastolic dysfunction, angina, and ventricular arrhythmias. Transapical myectomy to augment left ventricular cavity size can increase stroke volume and decrease left ventricular end-diastolic pressure. In this study, we describe early outcomes of patients with apical hypertrophic cardiomyopathy after transapical myectomy and compare survival with that of patients with hypertrophic cardiomyopathy listed for heart transplantation.

METHODS

Between September 1993 and March 2017, 113 symptomatic patients with apical hypertrophic cardiomyopathy underwent transapical myectomy. Clinical information, echocardiographic data, and follow-up were reviewed. With the use of a national database, survival was compared with that of patients with hypertrophic cardiomyopathy listed for heart transplantation.

RESULTS

In the surgical cohort, median (interquartile range) age was 50.8 (39.3-60.7) years, and 49 (43%) were male. Preoperatively, 108 patients (96%) were in New York Heart Association class III/IV. All patients underwent transapical myectomy. There were 4 (4%) deaths within 30 days of operation. At last follow-up, 76% of patients reported improvement in symptoms, and 3 patients (3%) subsequently underwent cardiac transplantation for recurrent heart failure. The estimated 1-, 5-, and 10-year survivals were 96%, 87%, and 74%, respectively. Survival appeared superior to patients with hypertrophic cardiomyopathy listed for heart transplant.

CONCLUSIONS

Apical myectomy is beneficial in severely symptomatic patients with apical hypertrophic cardiomyopathy. Early risk of the procedure is low, and approximately 76% maintain clinical improvement with resolution of symptoms. Long-term survival appears better than for patients listed for heart transplantation.

Advanced Heart Failure Management and Transplantation

Hypertrophic cardiomyopathy is a genetic heart disease with heterogeneous clinical features, including progression to advanced heart failure. The development of these symptoms can be related to outflow obstruction but in some patients reflects an underlying process of fibrosis and progressive ventricular dysfunction. For patients with end-stage disease, traditional heart failure therapies have not proved beneficial. As such, more advanced therapies, such as left ventricular assist device or cardiac transplantation, should be considered for these patients. Although left ventricular assist device support is used infrequently due to the restrictive physiology underlying hypertrophic cardiomyopathy, transplant represents an effective treatment, with encouraging long-term outcome data.

Verification of Heart Disease: Implications for a New Heart Transplantation Allocation System

OBJECTIVES

This study sought to determine the accuracy of the pre-transplantation clinical diagnosis of heart disease in the United Network for Organ Sharing (UNOS) database.

BACKGROUND

Because survival on the heart transplantation waitlist depends on underlying heart disease, a new allocation system will include the type of heart disease. Accuracy of the pre-transplantation clinical diagnosis and the effect of misclassification are unknown.

METHODS

We included all adults who received transplants at our center between January 2009 to December 2015. We compared the pre-transplantation clinical diagnosis at listing with pathology of the explanted heart and determined the potential effect of misclassification with the proposed allocation system.

RESULTS

A total of 334 patients had the following clinical cardiac diagnoses at listing: 148 had dilated cardiomyopathy, 19 had restrictive cardiomyopathy, 103 had ischemic cardiomyopathy, 24 had hypertrophic cardiomyopathy, 11 had valvular disease, 16 had congenital heart disease (CHD), and 13 patients had a diagnosis of "other." Pathology of the explanted hearts revealed 82% concordance and 18% discordance (10% coding errors and 8% incorrect diagnosis). The most common incorrect diagnoses were sarcoidosis (66%), arrhythmogenic right ventricular dysplasia (60%), and other causes of predominately right-sided heart failure (33%). Among the misclassified diagnoses, 40% were listed as UNOS status 2, 8% remained at status 2 at transplantation, and only sarcoidosis and CHD were potentially at a disadvantage with the new allocation.

CONCLUSIONS

There is high concordance between clinical and pathologic diagnosis, except for sarcoidosis and genetic diseases. Few misclassifications result in disadvantages to patients based on the new allocation system, but rare diseases like sarcoidosis remain problematic. To improve the UNOS database and enhance outcome research, pathology of the explanted hearts should be required post-transplantation.

Impact of Advanced Therapies for Improving Survival to Heart Transplant in Patients with Hypertrophic Cardiomyopathy

Heart transplant has become an increasingly important option for patients with end-stage nonobstructive hypertrophic cardiomyopathy (HC). However, clinical details related specifically to the overall HC transplant experience remain sparse. We assessed outcomes of HC heart transplants, from 2002 to 2016, at Tufts Medical Center. Fifty-two nonobstructive severely symptomatic patients underwent evaluation at 47 ± 13 years; 11 (21%) declined or failed to qualify, most commonly because of co-morbidities (n = 7). Of the remaining 41 patients ultimately listed, 6 (15%) died of heart failure awaiting transplant (11%/year), 26 underwent transplant, and 9 remained active on the list. Survival rates on the waiting list depended on ≥1 treatment intervention: inotropic medications (n = 20), ventricular assist devices (n = 7), or implantable defibrillators terminating ventricular tachyarrhythmias (n = 7). Of the 26 transplanted patients, 24 survived for 4.8 ± 3.4 years (up to 12), including 23 who are currently alive. The survival rate 5 years post transplant is 92%. Compared with heart transplants for other cardiomyopathies, patients with HC had similar mortality while wait-listed and post transplant (p = 0.77 and 0.13, respectively). In conclusion, a large proportion of patients with HC considered for transplant ultimately received hearts and experienced excellent short- and long-term survival rates. The survival rate on the waiting list was directly attributable to major interventions: implantable cardioverter-defibrillators, inotropic drugs, and ventricular assist devices, and the perception that patients with HC have low wait-list mortality risk does not appear justified. Neither normal ejection fraction nor peak oxygen consumption > 14 ml/kg/min should exclude drug refractory severely symptomatic patients with HC from heart transplant consideration.

Heart transplantation in cardiac amyloidosis

"Cardiac amyloidosis" is the term commonly used to reflect the deposition of abnormal protein amyloid in the heart. This process can result from several different forms, most commonly from light-chain (AL) amyloidosis and transthyretin (ATTR) amyloidosis, which in turn can represent wild-type (ATTRwt) or genetic form. Regardless of the origin, cardiac involvement is usually associated with poor prognosis, especially in AL amyloidosis. Although several treatment options, including chemotherapy, exist for different forms of the disease, cardiac transplantation is increasingly considered. However, high mortality on the transplantation list, typical for patients with amyloidosis, and suboptimal post-transplant outcomes are major issues. We are reviewing the literature and summarizing pros and cons of listing patients with amyloidosis for cardiac or combine organ transplant, appropriate work-up, and intermediate and long-term outcomes. Both AL and ATTR amyloidosis are included in this review.

Comparative Analysis of Four Scores to Stratify Patients With Heart Failure and Reduced Ejection Fraction

There are several prognostic risk scores available for patients with heart failure with reduced ejection fraction (HFrEF) that can aid in the decision of listing candidates for heart transplant (HTx). A direct comparison between these scores has not been performed. Therefore, our objective was to evaluate the calibration and discriminative power of 4 contemporary HF scores. A retrospective analysis of 259 patients with HFrEF who underwent cardiopulmonary exercise test was conducted. The Heart Failure Survival Score (HFSS), Seattle Heart Failure Model (SHFM), Meta-analysis Global Group in Chronic Heart Failure (MAGGIC), and Metabolic Exercise Cardiac Kidney Index (MECKI) were compared. During the first year, 7 deaths occurred (6 cardiovascular) and 25 patients were submitted to HTx (8 urgent). Over a 2-year period, 14 deaths occurred (10 cardiovascular) and 34 patients received an HTx (8 urgent). Calibration analysis showed that SHFM and HFSS tended to underestimate event occurrence, whereas MAGGIC and MECKI tended to overestimate risk, especially in the highest risk subgroups. Interestingly, MECKI score at 1 year was well calibrated (expected similar to observed events). Overall, the MECKI score consistently showed better discrimination ability for all studied end points (areas under the curve between 0.8 and 0.9). In conclusion, along with HFSS and SHFM, the MECKI score can also be used to aid treatment decisions, such as HTx listing with the advantage of being very well calibrated at 1-year intervals, which might allow us to avoid the pitfalls of under/overestimation of risk.