Weaning from ventricular assist device support after recovery from left ventricular failure with or without secondary right ventricular failure

Abstract

Although complete myocardial recovery after ventricular assist device (VAD) implantation is rather seldom, systematic search for recovery is worthwhile because for recovered patients weaning from VADs is feasible and can provide survival benefits with long-term freedom from heart failure (HF) recurrence, even if a chronic cardiomyopathy was the primary cause for the drug-refractory HF necessitating left ventricular (LVAD) or biventricular support (as bridge-to-transplantation or definitive therapy) and even if recovery remains incomplete. LVAD patients explanted for myoacardial recovery compared to those transplanted from LVAD support showed similar survival rates and a significant proportion of explanted patients can achieve cardiac and physical functional capacities that are within the normal range of healthy controls. In apparently sufficiently recovered patients, a major challenge remains still the pre-explant prediction of the weaning success which is meanwhile reliably possible for experienced clinicians. In weaning candidates, the combined use of certain echocardiography and right heart catheterization parameters recorded before VAD explantation can predict post-weaning cardiac stability with good accuracy. However, in the absence of standardization or binding recommendations, the protocols for assessment of native cardiac improvement and also the weaning criteria differ widely among centers. Currently there are still only few larger studies on myocardial recovery assessment after VAD implantation. Therefore, the weaning practice relies mostly on small case series, local practice patterns, and case reports, and the existing knowledge, as well as the partially differing recommendations which are based mainly on expert opinions, need to be periodically systematised. Addressing these shortcomings, our review aims to summarize the evidence and expert opinion on the evaluation of cardiac recovery during mechanical ventricular support by paying special attention to the reliability of the methods and parameters used for assessment of myocardial recovery and the challenges met in both evaluation of recovery and weaning decision making.

Keywords: Dilated cardiomyopathy; echocardiography; heart failure; myocardial recovery; ventricular assist devices (VADs); ventricular function.

Figure 1

Timeline showing some of the major progresses and achievements in the selective use of LVADs as a BTR. *, Osaka Cardiovascular Center; **, German Heart Center Berlin; ^†, Texas Heart Institute and Columbia Presbyterian Medical Center; ^‡, Royal Brompton & Harefield NHS Foundation Trust, London; ^#, 102 LVADs and 14 biventricular assist devices primarily designed as BTT which were explanted in the German Heart Center Berlin since 1995 (chronic non-ischemic cardiomyopathy was the underlying cause for VAD implantation in 63 of those patients). BTT, bridge-to-transplantation; LVAD, left ventricular assist device; IDCM, idiopathic dilated cardiomyopathy; HF, heart failure; CF, continuous flow; US, United States of America; VAD, ventricular assist device. With Ref. (7,9,15-19).

Figure 2

Evaluation of cardiac recovery in LVAD recipients based on ECHO and RHC examinations obtained in resting conditions. *, especially in patients with adequate renal, hepatic, neurologic and pulmonary function. ECHO, echocardiography; RHC, right heart catheterization; TTE, transthoracic ECHO; LVAD, left ventricular assist device; LV and RV, left and right ventricle, respectively; LVEDD, LV end-diastolic diameter; LVEF, LV ejection fraction; BSA, body surface area; TR, tricuspid regurgitation; VTI, velocity-time integral; LVOT, LV outflow tract; PW, pulsed wave; CF, continuous flow; SV, stroke volume; PCWP, pulmonary capillary wedge pressure; CI, cardiac index; RAP, right atrial pressure.

Figure 3

Evaluation of cardiac recovery in BiVAD recipients based on ECHO and RHC examinations obtained in resting conditions. *, adequate anticoagulation is mandatory; ventricular unloading interruption should be started with the RV pump (~30 sec before interruption of the LV pump). BiVAD, biventricular assist device; ECHO, echocardiography; RHC, right heart catheterization; LV and RV, left and right ventricle, respectively; RVAD and LVAD, right and left ventricular assist device; RA, right atrium; RVEDD_RVOT, RV end-diastolic diameter at the RV outflow tract; S/L, end-diastolic short-/long-axis ratio; PW, pulsed-wave; TAPSE and TAPS’, tricuspid annulus peak systolic excursion and velocity, respectively; LAI_RV, RV load adaptation index; VTI_LVOT, velocity-time integral in the LV outflow tract; CVP, central venous pressure; CI, cardiac index.

Figure 4

Pre-explant prediction of post-explant cardiac stability in LVAD recipients and major risk factors for recurrence of heart failure after LVAD explantation (1,2,7,18,19,30,36,41,43,66,69). *, off-pump trials were conducted under resting conditions, without any inotropic myocardial support; **, the predictive value of transthoracic ECHO parameters for ≥5 years freedom from post-explant HF recurrence is valid only for patients with normal off-pump hemodynamic RHC measurements before explantation; ^†, off-pump trials for ECHO measurements implied either short-term pump stops (true off-pump trial) or short-term pump rate reductions to values resulting in ±0 flow in one cardiac cycle, depending on whether the LVAD is a pulsatile-flow or a continuous-flow (CF) pump, respectively; ^††, no alteration after maximum recovery between and during further pre-explant follow-up off-pump controls; ^‡, in CF LVAD recipients, hemodynamic parameter measurements were obtained during repeated pump stops with simultaneous balloon occlusion of the outflow graft; ^#, RV load adaptation index (LAIRV) values between 14–18. LV and RV, left and right ventricle, respectively; LVAD, left ventricular assist device; ECHO, echo-cardiography; RHC, right heart catheterization; PV, predictive value; HF, heart failure; LVEF, LV ejection fraction; LVEDD, LV end-diastolic diameter; BSA, body surface area; RWTLV, LV relative wall thickness ([posterior wall thickness + ventricular septum thickness]/LVEDD); S/LED, end-diastolic short/long axis ratio measured in the apical 4C, four chamber view; Sm, peak systolic wall motion velocity (measured at the basal posterior.