A Holistic View of Advanced Heart Failure

Abstract

Advanced heart failure (HF) may occur at any level of left ventricular (LV) ejection fraction (LVEF). The latter, which is widely utilized for the evaluation of LV systolic performance and treatment guidance of HF patients, is heavily influenced by LV size and geometry. As the accurate evaluation of ventricular systolic function and size is crucial in patients with advanced HF, the LVEF should be supplemented or even replaced by more specific indices of LV function such as the systolic strain and cardiac power output and size such as the LV diastolic diameters and volumes. Conventional treatment (cause eradication, medications, devices) is often poorly tolerated and fails and advanced treatment (mechanical circulatory support [MCS], heart transplantation [HTx]) is required. The effectiveness of MCS is heavily dependent on heart size, whereas HTx which is effective in the vast majority of the cases is limited by the small donor pool. Expanding the MCS indications to include patients with small ventricles as well as the HTx donor pool are major challenges in the management of advanced HF.

Keywords: advanced heart failure; heart transplantation; mechanical circulatory support; shock.

Figure 1

Survival and hospitalizations after advanced heart failure (HF). (A) The Kaplan-Meier survival curves according to ejection fraction. (B) Mean cumulative hospitalizations after advanced heart failure according to ejection fraction. HFmrEF = heart failure with mid-range ejection fraction; HFpEF = heart failure with preserved ejection fraction; HFrEF = heart failure with reduced ejection fraction. Adapted with permission from Ref. [7]. Copyright © 2022 by the American College of Cardiology Foundation. Published by Elsevier.

Figure 2

The proposed mechanism of progression from chronic compensated to acute heart failure is summarized in this figure. Sodium retention and fluid expansion result in an increase in unstressed volume and subsequent splanchnic congestion. This process is slow and takes days to weeks. The fast component often observed in the few days before decompensation is driven by autonomic imbalance with overactivity of the sympathetic nervous system. This results in an intercompartmental fluid shift into the central circulation with a subsequent accelerated increase in central filling pressures. Rapid fluid mobilization also occurs with activity and can explain exercise limitations experienced by heart failure patients. Adapted with permission from Ref. [12]. Copyright © 2022. Published on behalf of the American Heart Association, Inc., by Wiley.

Figure 3

(a) Cardiac Power Output (CPO) accurately reflects left ventricular stroke work per minute (LV SW min⁻¹) over a wide range of inotropic states. Any rise or fall of LV SW min⁻¹ corresponds to an equivalent change in CPO; (b) Left ventricular ejection fraction (LVEF) did not correlate left ventricular stroke work per minute (LV SW min⁻¹). Adapted with permission from Ref. [48]. Copyright © 2022, The Author(s). Published by Springer Nature.

Figure 4

Summary of conventional and advanced treatment of advanced heart failure.

Figure 5

Acute mechanical circulatory support devices for the left ventricle. Pressure volume loops demonstrating hemodynamic effects of acute mechanical circulatory support devices on the left ventricle. (A) IABP reduces LV afterload but does not unload the ventricle. (B) VA-ECMO increases the wall stress and afterload of the LV and does not unload without an LV vent (C) The LA-FA bypass, or TandemHeart device, unloads the left atrium, thereby decreasing LV end-diastolic volumes. (D) The Impella device unloads the LV by decreasing end-diastolic volume and pressure. PHP= HeartMate Percutaneous Heart Pump (St. Jude Inc). * Investigational. Adapted with permission from Ref. [81]. Copyright © 2022. Published by Elsevier B.V. on behalf of Cardiological Society of India.

Figure 6

(a) Physiologic principle of unloading the left atrium to descending aorta. Increase in pump speed during systole to overcome the gradient from left atrium to aorta. (b) Cross-sectional graphic presentation of the PulseVAD. 1. Titanium casing. 2. Hydrodynamically suspended rotor. 3. Inlet tract. 4. Rare earth magnets. 5. Outlet tract. 6. Motor coils. Adapted with permission from Ref. [90]. Copyright © 2022, The Author(s). Published by Springer Nature.