Myocardial recovery and the failing heart: medical, device and mechanical methods

Effect of sacubitril/valsartan on cardiac remodeling compared with other renin-angiotensin system inhibitors: a difference-in-difference analysis of propensity-score matched samples

BACKGROUND

In patients with heart failure with reduced ejection fraction (HFrEF), treatment with sacubitril-valsartan (S/V) may reverse left ventricular remodeling (rLVR). Whether this effect is superior to that induced by other renin-angiotensin system (RAS) inhibitors is not well known.

METHODS

HFrEF patients treated with S/V (n = 795) were compared, by propensity score matching, with a historical cohort of 831 HFrEF patients (non-S/V group) treated with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (RAS inhibitors). All patients were also treated with beta-blockers and shared the same protocol with repeat echocardiogram 8-12 months after starting therapy. The difference-in-difference (DiD) analysis was used to evaluate the impact of S/V on CR indices between the two groups.

RESULTS

After propensity score matching, compared to non-S/V group (n = 354), S/V group (n = 354) showed a relative greater reduction in end-diastolic and end-systolic volume index (ESVI), and greater increase in ejection fraction (DiD estimator =  + 5.42 mL/m2, P = 0.0005; + 4.68 mL/m2, P = 0.0009, and + 1.76%, P = 0.002, respectively). Reverse LVR (reduction in ESVI ≥ 15% from baseline) was more prevalent in S/V than in non-S/V group (34% vs 26%, P = 0.017), while adverse LVR (aLVR, increase in ESVI at follow-up ≥ 15%) was more frequent in non-S/V than in S/V (16% vs 7%, P < 0.001). The beneficial effect of S/V on CR over other RAS inhibitors was appreciable across a wide range of patient's age and baseline end-diastolic volume index, but it tended to attenuate in more dilated left ventricles (P for interaction = NS for both).

CONCLUSION

In HFrEF patients treated with beta-blockers, sacubitril/valsartan is associated with a relative greater benefit in LV reverse remodeling indices than other RAS inhibitors.

Myocardial Recovery

In this paper, the feasibility of myocardial recovery is analyzed through a literature review. First, the phenomena of remodeling and reverse remodeling are analyzed, approached through the physics of elastic bodies, and the terms myocardial depression and myocardial recovery are defined. Continuing, potential biochemical, molecular, and imaging markers of myocardial recovery are reviewed. Then, the work focuses on therapeutic techniques that can facilitate the reverse remodeling of the myocardium. Left ventricular assist device (LVAD) systems are one of the main ways to promote cardiac recovery. The changes that take place in cardiac hypertrophy, extracellular matrix, cell populations and their structural elements, β-receptors, energetics, and several biological processes, are reviewed. The attempt to wean the patients who experienced cardiac recovery from cardiac assist device systems is also discussed. The characteristics of the patients who will benefit from LVAD are presented and the heterogeneity of the studies performed in terms of patient populations included, diagnostic tests performed, and their results are addressed. The experience with cardiac resynchronization therapy (CRT) as another way to promote reverse remodeling is also reviewed. Myocardial recovery is a phenomenon that presents with a continuous spectrum of phenotypes. There is a need for algorithms to screen suitable patients who may benefit and identify specific ways to enhance this phenomenon in order to help combat the heart failure epidemic.

Novel Plug Device for HeartMate 3 Explantation: First Multicenter Experience

Patients undergoing explantation of left ventricular assist devices (LVADs) after improvement of myocardial function remain a minority. Nevertheless, considering the growing population of LVAD patients, increasing demand for new explantation strategies is expected. Herein, we present a retrospective review of seven patients undergoing HeartMate3 explantation with the use of a custom-made apical ring plug in four medical centers. The primary outcome was status at intensive care unit discharge. Secondary outcomes included perioperative complications and transfusions. Six out of seven patients were males. The median age at explantation and time on LVAD support was 35 years (range:13-73) and 10 months (range:9-24), respectively. No technical difficulties were experienced during plug implantation via a conventional sternotomy or through a left lateral thoracotomy, either with or without cardiopulmonary bypass. Perioperative transfusions ranged from 0 to 3 units/patient. No re-operations for bleeding, hemorrhagic, embolic, or plug-related infective events were observed. Heparin was started 6 hours after surgery as a bridge to oral anticoagulation (international normalized ratio: 2-2.5). All patients were discharged alive from intensive care unit. This novel plug device for HeartMate3 explantation was successfully and safely implanted in this first patient series. Notwithstanding, its use should still be considered off-label and larger studies are required to investigate its long-term results.

Role of Endothelial and Mesenchymal Cell Transitions in Heart Failure and Recovery Thereafter

Background: Mechanisms of myocardial recovery are not well elucidated.

Methods: 3-month-old C57/BL6 mice were treated with Angiotensin-II infusion and N (w)-nitro-L-arginine methyl ester in drinking water to induce HF at 5 weeks. These agents were discontinued, and animals studied with echocardiographic, histological and genetic assessment every 2 weeks until week 19. mRNA was extracted from these samples and human pre-post LVAD samples.

Results: Histologic and echo characteristics showed progressive worsening of cardiac function by week 5 and normalization by week 19 accompanied by normalization of the transcriptional profile. Expression of 1,350 genes were upregulated and 3,050 genes down regulated in HF compared to controls; during recovery, this altered gene expression was largely reversed. We focused on genes whose expression was altered during HF but reverted to control levels by Week 19. A gene ontology (GO) analysis of this cohort of genes implicated pathways involved in EndoMT and MEndoT. The cohort of genes that were differentially regulated in heart failure recovery in the murine model, were similarly regulated in human myocardial samples obtained pre- and post-placement of a left ventricular assist device (LVAD). Human end stage HF myocardial samples showed cells with dual expressed VE-Cadherin and FSP-1 consistent with cell fate transition. Furthermore, we observed a reduction in fibrosis, and an increase in endothelial cell density, in myocardial samples pre- and post-LVAD.

Conclusions: Cell fate transitions between endothelial and mesenchymal types contribute to the pathophysiology of heart failure followed by recovery.

Left ventricular assist device-induced reverse remodeling: it's not just about myocardial recovery

INTRODUCTION

The abnormal structure, function and molecular makeup of dilated cardiomyopathic hearts can be partially normalized in patients supported by a left ventricular assist device (LVAD), a process called reverse remodeling. This leads to recovery of function in many patients, though the rate of full recovery is low and in many cases is temporary, leading to the concept of heart failure remission, rather than recovery. Areas covered: We summarize data indicative of ventricular reverse remodeling, recovery and remission during LVAD support. These terms were used in searches performed in Pubmed. Duplication of topics covered in depth in prior review articles were avoided. Expert commentary: Although most patients undergoing mechanical circulatory support (MCS) show a significant degree of reverse remodeling, very few exhibit sufficiently improved function to justify device explantation, and many from whom LVADs have been explanted have relapsed back to the original heart failure phenotype. Future research has the potential to clarify the ideal combination of pharmacological, cell, gene, and mechanical therapies that would maximize recovery of function which has the potential to improve exercise tolerance of patients while on support, and to achieve a higher degree of myocardial recovery that is more likely to persist after device removal.