The following are key points to remember from a state-of-the-art review on advanced heart failure therapies for hypertrophic cardiomyopathy (HCM):

1. Up to 1 in 15 patients with HCM progress to advanced heart failure (AHF). These patients typically present with mild systolic dysfunction, left ventricular (LV) hypertrophy, and advanced diastolic dysfunction with pulmonary hypertension.
2. Clinical predictors of AHF in HCM include atrial fibrillation, family history of AHF-HCM with reduced ejection fraction (EF), treated ventricular arrhythmia, and septal myectomy. Substantial late gadolinium enhancement can predict progression to AHF in HCM when EF is borderline (50-65%).
3. Mild systolic dysfunction in HCM is also associated with a 10-fold greater risk for death or heart transplant in 10 years compared with HCM with preserved EF.
4. Cardiopulmonary exercise testing helps identify exercise-induced left atrial hypertension in HCM patients. Both peak oxygen consumption and ventilatory efficiency are strong predictors of progression to AHF in HCM patients, irrespective of their EF.
5. Right heart catheterization in HCM patients with AHF is notable for severely increased pulmonary capillary wedge pressures with a decreased cardiac output. For patients with New York Heart Association class III/IV symptoms with normal resting hemodynamics, exercise testing can be useful.
6. Pulmonary hypertension (PH) is common in HCM patients with AHF due to advanced diastolic dysfunction. Irreversible PH is not uncommon in these patients and can lead to ineligibility to heart transplant and also cause post-transplant right ventricular dysfunction.
7. In HCM-AHF, LV hypertrophy and small chamber size increase risk associated with durable and percutaneous left ventricular assist devices (LVADs) by causing cannula obstruction leading to cannula thrombosis and death. Accordingly, LVAD should be considered only in subgroups of HCM-AHF patients with LV hypertrophy regression and LV enlargement.
8. When percutaneous temporary mechanical support is needed in HCM-AHF, intra-aortic balloon pump and venoarterial extracorporeal membrane oxygenation (VA-ECMO) are free of issues due to extracardiac placement.
9. Heart transplant is the best treatment for HCM-associated AHF. HCM patients experience higher risk for 90-day mortality post-transplant, likely due to PH. However, 1- and 5-year mortality are no different compared to other transplanted patients.
10. In an analysis of the United Network for Organ Sharing (UNOS) registry from 2013–2022, HCM-AHF patients had similar filling pressures but slightly lower cardiac index and higher pulmonary vascular resistance than other candidates listed for transplant. With change in the transplant listing system, HCM patients have higher priority status at the time of transplant than in the prior allocation system. This correlated with a decrease in waitlist time and similar 1-year post-transplant survival than non-HCM patients.

Clinical Topics: Heart Failure and Cardiomyopathies

Keywords: Advanced Heart Failure, Cardiomyopathy, Hypertrophic

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