A case series of cardiac amyloidosis patients supported by continuous‐flow left ventricular assist device

Abstract

The two main types of cardiac amyloidosis (CA), light chain (AL) and transthyretin (ATTR), typically cause restrictive cardiomyopathy (RCM) that may progress to advanced heart failure prompting consideration for orthotopic heart transplantation (OHT) or left ventricular assist device (LVAD). Limited data exist on continuous-flow LVAD (CF-LVAD) use in CA patients, as this is not traditionally considered feasible due to the non-dilated and restrictive nature of the cardiac chambers. Herein, we describe the outcomes of CA patients on CF-LVAD therapy at our institution. Our single-centre case series retrospectively identified seven CA patients (mean age 68 ± 9 years, 86% male, 71% African-American, 57% Intermacs 1–2) all supported by CF-LVAD (five centrifugal and two axial) from 2009 to 2021 (Table 1 and Supporting Information, Tables S1–S3). Five patients had ATTR amyloidosis (three hereditary due to p.Val142Ile and two wild type), and two had AL amyloidosis. This study complies with the Declaration of Helsinki and was approved by the institutional ethics committee with waiver for informed consent. Two CA patients with pulsatile pumps were excluded. The CF-LVAD served as bridge to transplant (BTT) in three patients and as destination therapy (DT) in four patients. The entire cohort was alive at 12 months post-LVAD and had a median survival of 2.01 years on LVAD support only and 3.6 years overall. The two AL amyloidosis patients with DT-LVAD survived the longest; one died after 48.3 months, and one remains alive at 66.9 months. Both achieved complete hematologic remission after anti-plasma cell therapy. Three patients (43%) died: one post-OHT from acute severe cellular rejection for non-compliance with immunosuppression; and two others whilst on device support, one from a fatal cerebral bleed after 43.1 months and the other from complications secondary to a device-related infection after 48.3 months. All patients had an LV ejection fraction (LVEF) ≤ 45%, with variable LV end-diastolic diameter (LVEDD). Two patients with a dilated LVEDD ≥ 5.8 cm were bridged to OHT. Of five patients with LVEDD ≤ 5.6 cm, four had intra-operative LV debulking that entailed multiple extensive core resections or myectomy, a decision made by the cardiothoracic surgeon during direct LV cavity visualization after apical core resection. All three with smaller LVEDD ≤ 4.5 cm had no clinically documented suction events that led to malignant arrhythmias, hypotension, pump thrombosis, or right heart failure (RHF). However, one of these patients with DT-Heartmate II and LVEDD 4.5 cm had LV inflow cannula-induced premature ventricular contractions resulting in recurrent ventricular tachycardia (VT). There were no speed ramp downs or changes in pulsatility index to suggest suction events, and there was no further VT after successful ablation. In most patients, the pump speed was kept steady and at a relatively lower target speed than in non-CA patients (Supporting Information, Table S1). Heart failure, diuretic, and anti-arrhythmic therapies were adjusted in all patients based on their mean arterial pressure, renal function, electrolytes, volume status, and arrhythmia burden; however, negative inotropes (e.g. beta-blockers) and high-dose diuretics were used with caution or avoided. Aspirin (81–325 mg daily) and Coumadin (INR goal 2–3) were reduced in patients with bleeding. One patient was peri-operatively safely bridged with bivalirudin to anti-coagulation for heparin-induced thrombocytopenia. Right heart failure requiring right ventricular assist device (RVAD) and/or inotropes ≥14 days occurred in three patients (43%) at ~0.5, 6, and 23 months (Table 1 and Supporting Information, Table S1). They all had a pre-implant pulmonary artery pulsatility index (PAPI) of ≤1.5. The two patients who required an RVAD had severe pre-implant echocardiographic RV dysfunction; the RVAD was implanted shortly after CF-LVAD in the one patient bridged to heart–kidney transplantation, and the RVAD was placed almost 2 years after CF-LVAD in the other patient also successfully bridged to heart transplantation. The third patient with RHF after DT-Heartmate II was on long-term inotropes and died from cerebral bleeding complications due to a mechanical fall. This study highlights several key findings: first, in our cohort, the survival was 100% at 12 months post-CF-LVAD with a median survival of 2.01 years on device support and LETTER TO THE EDITOR