Outcomes of Heart Transplantation in Cardiac Amyloidosis Patients: A Single Center Experience

Perioperative implications of amyloidosis and amyloid cardiomyopathy: A review for anesthesiologists

It is well recognized that amyloid protein can infiltrate many regions of the body. This can include the peripheral nerves, the liver, kidney, spleen, the gastrointestinal tract, and most importantly the myocardium. The amyloid proteins that cause cardiomyopathy may come from genetically altered liver genes (transthyretin amyloid, ATTR) or from the bone marrow with malignant plasma cells (light chain amyloid, AL) generating the aberrant protein. These two types of amyloidosis cause significant damaging effects on both the myocardial cells as well as the conduction system of the heart. The resultant changes can produce dyspnea and exercise intolerance which is thought to be secondary to diastolic dysfunction and reduced stroke volume. This subclinical decompensation poses a significant problem for members of a care team as it often goes unrecognized. In the operating room patients are exposed to dramatic hemodynamic changes and may have difficult airways, autonomic dysfunction, and conduction abnormalities. Although the topic of amyloidosis is well described in cardiology literature, it is underdiagnosed. The purpose of this review is to describe some of the pathophysiology behind the principle proteins that cause cardiac amyloidosis and to comprehensively describe perioperative considerations for anesthesia providers.

Cardiac Amyloidosis: A Contemporary Review of Medical and Surgical Therapy

Amyloidosis is a systemic disease initiated by deposition of misfolded proteins in the extracellular space, due to which multiple organs may be affected concomitantly. Cardiac amyloidosis, however, remains a major cause of morbidity and mortality in this population due to infiltrative /restrictive cardiomyopathy. This review attempts to focus on contemporary medical and surgical therapies for the different types of cardiac amyloidosis. Amyloidosis affecting the heart are predominantly of the transthyretin type (acquired in the older or genetic in the younger patients), and the monoclonal immunoglobulin light chain (AL) type which is solely acquired. A rare form of secondary amyloidosis AA type can also affect the heart due to excessive production and accumulation of the acute-phase protein called Serum Amyloid A" (SAA) in the setting of chronic inflammation, cancers or autoinflammatory disease. More commonly AA amyloidosis is seen in the liver and kidney. Other rare types are Apo A1 and Isolated Atrial Amyloidosis (AANF). Medical therapies have made important strides in the clinical management of the two common types of cardiac amyloidosis. Surgical therapies such as mechanical circulatory support and cardiac transplantation should be considered in appropriate patients. Future research using AI driven algorithms for early diagnosis and treatment as well as development of newer genetic engineering technologies will drive improvements in diagnosis, treatment and patient outcomes.

Outcomes in patients with cardiac amyloidosis undergoing heart transplantation: the eurotransplant experience

BACKGROUND

When advanced heart failure occurs in cardiac amyloidosis, prognosis is poor. In this setting heart transplantation (HTX) is a treatment option for selected patients. We here present the results of post-transplantation outcomes in cardiac amyloidosis within the Eurotransplant area, investigating possible predictors of survival.

METHODS

Of 115 patients undergoing HTX due to cardiac amyloidosis in the Eurotransplant region between November 1987 and May 2020, detailed assessment prior to transplantation was available in 85 patients. The present study was conducted in a retrospective approach. Primary endpoint was mortality after HTX. Baseline variables were entered in a Cox proportional hazards model with the primary endpoint as a dependent variable.

RESULTS

Median overall survival following HTX was 6.3 years in the overall collective and the subgroup. Univariate Cox proportional hazards model revealed a significant relationship between overall survival and the transplantation period (2008 to 2020 vs 1987 to 2007; median survival 9.7 years vs 1.8 years, hazard ratio 0.45, p = 0.01). Further predictors were albumin concentration (hazard ratio 0.92, p < 0.001), and systolic blood pressure (hazard ratio 0.96, p < 0.001). The transplant period as well as albumin concentration remained significant independent predictors in the AL sub cohort in a multivariate Cox proportional hazards model.

CONCLUSIONS

HTX is a viable treatment option for patients at an advanced stage of cardiac amyloidosis as overall survival after transplantation has improved in the modern age. Patients at a very advanced stage of the disease, indicated by low serum albumin and blood pressure, show worse outcomes following HTX. Optimal timing and careful patient selection may therefore be particularly important to further improve post-HTX survival in amyloidosis patients.

Heart Transplantation, Either Alone or Combined With Liver and Kidney, a Viable Treatment Option for Selected Patients With Severe Cardiac Amyloidosis

Heart transplantation in cardiac amyloidosis (CA) patients is possible and generally considered for transplantation if other organs are not affected. In this study, we aimed to describe and assess outcome in patients following heart transplantations at our CA referral center.

Methods

We assessed all CA patients that had heart transplantations at our center between 2005 and 2018. Patients with New York Heart Association status 3 out of 4, with poor short-term prognosis due to heart failure, despite treatment, and without multiple myeloma, systemic disease, severe neuropathic/digestive comorbidities, cancer, or worsening infections were eligible for transplantation. Hearts were transplanted by bicaval technique. Standard induction and immunosuppressive therapies were used. Survival outcome of CA patients after transplantation was compared with recipients with nonamyloid pathologies in France.

Results

Between 2005 and 2018, 23 CA patients had heart transplants: 17 (74%) had light chain (light chain amyloidosis [AL]) and 6 (26%) had hereditary transthyretin (hereditary transthyretin amyloidosis [ATTRv]) CA. Also, 13 (57%) were male, and the mean age at diagnosis was 56.5 y (range, 47.7-62.8). Among AL patients, 13 had heart-only and 5 had heart-kidney transplantations. Among ATTRv patients, 1 had heart-only and 5 had heart-liver transplantations. The 1-y survival rate after transplantation was 78%, 70% with AL, and 100% with ATTRv. At 2 y, 74% were alive: 65% with AL and 100% with ATTRv.

Conclusion

After heart transplantation, French CA and nonamyloid patients have similar survival outcomes. Among CA patients, ATTRv patients have better prognosis than those with AL, possibly due to the combined heart-liver transplantation. Selected CA patients should be considered for heart transplantations.

Cardiac Amyloidosis

Amyloid deposits are defined by their tinctorial properties. Under the light microscope amyloid deposits are eosinophilic and amorphous when stained with hematoxylin and eosin. With Congo red staining the deposits are positive and under polarized light will exhibit green birefringence. Sixty years later electron microscopy demonstrated that all deposits were fibrillar. All amyloid deposits are protein derived. The clinical characteristics will be driven by the nature of the protein subunit. In cardiology, the 2 most common subunits accounting for well more than 90% of cardiac amyloidosis are either immunoglobulin light chain, amyloid light-chain (AL) amyloidosis, or transthyretin; transthyretin (TTR) amyloidosis. Although 70% of patients with systemic amyloidosis have cardiac involvement the diagnosis is made by cardiologists only 20% of the time, suggesting significant gaps in knowledge in how to establish a workflow to arrive at a diagnosis in everyday practice.

Prevalence and Clinical Outcomes of Transthyretin Amyloidosis: A Systematic Review and Meta-analysis

BACKGROUND

Systematic evidence on the prevalence and clinical outcome of transthyretin amyloidosis (ATTR) is missing. We explored: a) the prevalence of cardiac amyloidosis in various patient subgroups, b) survival estimates for ATTR subtypes and c) the effects of novel therapeutics on the natural course of disease.

METHODS

A systematic review of literature published in Medline before 31/12/2021 was performed for the prevalence of cardiac amyloidosis & all-cause mortality of ATTR patients. Extracted data included sample size, age, sex, and all-cause mortality at 1, 2 and 5-years. Subgroup analyses were performed for ATTR subtype i.e., wild type ATTR (wtATTR) vs. hereditary ATTR (htATTR), htATTR genotypes and treatment subgroups.

RESULTS

We identified a total of 62 studies (n=277,882 individuals) reporting the prevalence of cardiac amyloidosis, which was high among patients with a hypertrophic cardiomyopathy phenotype, HFpEF, and elderly with aortic stenosis. Data on ATTR mortality were extracted from 95 studies (n=18,238 ATTR patients). Patients with wtATTR were older (p=7x10^-10 ) and more frequently male (p=5x10^-20 ) vs. htATTR. The 2-year survival of ATTR was 73.3% (95%CI 71.6-76.2); for non-subtyped ATTR 70.4% (95%CI 66.9-73.9), for wtATTR (76.0%, 95%CI: 73.0-78.9) and for htATTR (77.2%, 95%CI: 74.0-80.4); in meta-regression analysis wtATTR was associated with higher survival after adjusting for confounders. There was an interaction between survival and htATTR genotypes (p=10^-15 , Val30Met having the lowest and Val122Ile/Thr60Ala the highest mortality). ATTR 2-year survival was higher on tafamidis/patisiran compared to natural disease course (79.9%, 95%CI: 74.4-85.3 vs. 72.4%, 95%CI 69.8-74.9, p<0.05).

CONCLUSIONS

We report the prevalence of ATTR in various population subgroups and provide survival estimates for the natural course of disease and the effects of novel therapeutics. Important gaps in worldwide epidemiology research in ATTR were identified. This article is protected by copyright. All rights reserved.

Outcomes of heart transplantation in cardiac amyloidosis: an updated systematic review

Cardiac amyloidosis is one of the most common infiltrative cardiomyopathies that is characterized by the extracellular deposition of misfolded fibrillar protein. Several studies have previously found that patients with amyloid in the past have performed poorly after heart transplantation. Recent advancements in treatments have been made that have significantly improved outcomes in these patients. The study aimed to evaluate the outcomes of heart transplantation in cardiac amyloidosis. We systematically searched EMBASE, PubMed/MEDLINE, and Cochrane Library databases on 30 December 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We identified 22 studies that examined 42,951 patients with cardiac amyloidosis of which only 1,329 patients underwent isolated heart transplantation. Seven studies reported individual patient data. The results of 123 patients have been pooled for analysis. There were 70 male patients, 45 female patients, and eight patients who did not report their gender. Among the types of amyloids, 63 (51%) patients were found to have light chain amyloidosis (AL) and 33 (27%) patients had transthyretin amyloidosis (ATTR). Only 41 patients (33.3%) reported a monoclonal component. There were 30 patients with AL that underwent autologous hematopoietic stem cell transplant (ASCT). The mean survival of 24 out of 30 patients was 4.33 years. In addition, the reported data include 13 patients requiring intra-aortic balloon pump (IABP), six with cardiac resynchronization therapy (CRT), and four with implantable cardioverter defibrillator (ICD). With the current advancements in treatments in combination with a multidisciplinary approach and careful patient selection, patients undergoing heart transplantation for amyloidosis may have encouraging results in the current era. Further studies will be needed to evaluate the outcomes of heart transplantation in amyloidosis patients now that several advances have been made in the field.

State-of-the-art review on management of end-stage heart failure in amyloidosis: transplant and beyond

Cardiac involvement occurs in light-chain (AL), transthyretin wild-type (wtATTR), and hereditary (hATTR) amyloidosis; other types of amyloidosis account for < 5% of all cardiac amyloidosis (CA). CA can present subclinically on screening, insidiously with symptoms such as exertional dyspnea, or abruptly as cardiogenic shock. Initially, CA patients were thought to be poor candidates for transplant due to short long-term survival; however, there is a marked improvement in heart and multi-organ transplant outcomes over the past 10 years with newer treatments and improvements in support with temporary and durable mechanical circulatory support while awaiting transplant. Patients with AL CA were reported to have worse post-OHT outcomes than patients with ATTR CA, but this gap is quickly closing with improved patient selection, novel chemotherapeutics, and perhaps with selected use of bone marrow transplantation. Waitlist mortality and transplantation rates have markedly improved for CA after the United Network for Organ Sharing (UNOS) policy change in October 2018. In this review, we will evaluate contemporary data from the last 5 years on advances in the field of transplantation and mechanical circulatory support in this patient population.

Cardiac Transplantation and Mechanical Circulatory Support in Amyloidosis

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Cardiac transplantation for amyloidosis was once considered contraindicated owing to unacceptably high morbidity/mortality rates.

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Increased therapeutic options for AL and ATTR amyloidosis and improved pre-transplantation screening practices have led to markedly improved transplant outcomes over the past 10-15 years.

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Mechanical circulatory support options remain limited but can be considered in selected patients, particularly for those with larger ventricular cavities.

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Transplant prioritization rules may need to be reconsidered for amyloidosis patients to adequately prioritize AL amyloidosis patients, who are at increased risk of pre-transplantation mortality.

Intermediate-term outcomes of heart transplantation for cardiac amyloidosis in the current era

BACKGROUND

Cardiac amyloidosis (CA) has been historically noted with poor outcomes after heart transplant (HTx). However, strict patient selection, appropriate multi-organ transplant, and aggressive post-transplant therapy can result in favorable outcomes. We present the experience in the largest single-center cohort of CA patients post-HTx in the recent era.

METHODS

Between January 2010 and December 2018, 51 CA patients underwent HTx-13 light-chain amyloidosis (AL) and 38 transthyretin amyloidosis (ATTR), 49 were included. Endpoints included 3-year survival, freedom from cardiac allograft vasculopathy (CAV), and freedom from non-fatal major adverse cardiac events (NF-MACE).

RESULTS

Overall 3-year survival was 81.6% (69.2% for AL and 86% for ATTR) and was comparable to survival for patients transplanted for non-amyloid restrictive cardiomyopathy (RCM) in the same period (89%, p = .46). Three-year freedom from CAV (84% vs. 89%, p = .98), NF-MACE (82% vs. 83%, p = .96), and any-treated rejection (95% vs. 89%, p = .54) were also comparable in both groups. No recurrence in amyloid was noted in endomyocardial biopsies. Six patients (46%) with AL amyloidosis underwent autologous stem cell transplant 1-year post-HTx, and two patients (8%) with variant ATTR-CA underwent combined heart-liver transplant due to cardiac cirrhosis.

CONCLUSION

In the current era, both AL and ATTR cardiac amyloidosis patients have acceptable outcomes after heart transplantation.