Right ventricular function and cardiopulmonary performance among patients with heart failure supported by durable mechanical circulatory support devices

doi:10.1016/j.healun.2020.11.009

The Journal of Heart and Lung Transplantation

Volume 40, Issue 2, February 2021, Pages 128-137

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https://doi.org/10.1016/j.healun.2020.11.009 Get rights and content

BACKGROUND

Patients with continuous-flow left ventricular assist devices (CF-LVADs) experience limitations in functional capacity and frequently, right ventricular (RV) dysfunction. We sought to characterize RV function in the context of global cardiopulmonary performance during exercise in this population.

METHODS

A total of 26 patients with CF-LVAD (aged 58 ± 11 years, 23 males) completed a hemodynamic assessment with either conductance catheters (Group 1, n = 13) inserted into the right ventricle to generate RV pressure‒volume loops or traditional Swan‒Ganz catheters (Group 2, n = 13) during invasive cardiopulmonary exercise testing. Hemodynamics were collected at rest, 2 sub-maximal levels of exercise, and peak effort. Breath-by-breath gas exchange parameters were collected by indirect calorimetry. Group 1 participants also completed an invasive ramp test during supine rest to determine the impact of varying levels of CF-LVAD support on RV function.

RESULTS

In Group 1, pump speed modulations minimally influenced RV function. During upright exercise, there were modest increases in RV contractility during sub-maximal exercise, but there were no appreciable increases at peak effort. Ventricular‒arterial coupling was preserved throughout the exercise. In Group 2, there were large increases in pulmonary arterial, left-sided filling, and right-sided filling pressures during sub-maximal and peak exercises. Among all participants, the cardiac output‒oxygen uptake relationship was preserved at 5.8:1. Ventilatory efficiency was severely abnormal at 42.3 ± 11.6.

CONCLUSIONS

Patients with CF-LVAD suffer from limited RV contractile reserve; marked elevations in pulmonary, left-sided filling, and right-sided filling pressures during exercise; and severe ventilatory inefficiency. These findings explain mechanisms for persistent reductions in functional capacity in this patient population.

Section snippets

Patient population

Eligible volunteers were patients aged ≥18 years with advanced HFrEF and who were fully recovered ≥3 months from implantation of a commercially available CF-LVAD. Exclusion criteria included any non-cardiac factors that might adversely influence the ability to exercise (e.g., arthritis, peripheral vascular disease, pulmonary disease). Before enrollment, a detailed history and physical examination were completed by the senior author (W.K.C. III). Study procedures were explained to all

Subject characteristics

A total of 26 individuals with CF-LVAD participated in the study, with 13 participants in each group (Table 1) matched by age and habitus. The majority were middle-aged men and hemodynamically stable with normal Qc/index.

Effect of CF-LVAD pump speed modulations on RV function

LVAD characteristics during the ramp protocol, stratified by the type of pump, are displayed in Table 2. As expected, pump speed reductions were associated with an increase in peripheral pulsatility and reduction in mean arterial pressure, whereas increases in pump speed had

Discussion

The primary findings of this study are as follows: among patients with CF-LVAD, (1) RV function is minimally affected by acute modulations in pump speed; (2) during exercise, the right ventricle displays evidence of modest inotropic reserve, with increases in metrics of contractility when transitioning from rest to sub-maximal exercise; (3) patients with CF-LVAD experience marked increases in filling pressures even during sub-maximal workloads below VT; (4) beta blockers do not appear to

Conclusions

Whereas mechanical pumps normalize resting Qc, patients with CF-LVAD suffer from a number of hemodynamic and cardiopulmonary abnormalities during sub-maximal and peak exercises, which all contribute to the observed persistent reductions in functional capacity. The right heart has a modest degree of contractile reserve at sub-maximal levels of exercise below VT but an inability to further augment function at peak exercise in the face of persistently deranged hemodynamics and elevations in

Disclosure statement

W.K.C. III has received funding by the National Institutes of Health/National Heart, Lung, and Blood Institute Mentored Patient-Oriented Research Career Development Award (#1K23HLI32048-01) as well as the National Institutes of Health/National Center for Advancing Translational Sciences (#UL1TR002535), Susie and Kurt Lochmiller Distinguished Heart Transplant Fund, the Clinical Translational Science Institute at the University of Colorado Anschutz Medical Campus, and Medtronic Inc. M.H. has been

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Detecting right heart failure post left ventricular assist device (LVAD) is challenging. Sensitive pressure-volume loop assessments of right ventricle (RV) contractility may improve our appreciation of post-LVAD RV dysfunction.
Thirteen LVAD patients and 20 reference (non-LVAD) subjects underwent comparison of echocardiographic, right heart cath hemodynamic, and pressure-volume loop-derived assessments of RV contractility using end-systolic elastance (Ees), RV afterload by effective arterial elastance (Ea), and RV-pulmonary arterial coupling (ratio of Ees/Ea).
LVAD patients had lower RV Ees (0.20 ± 0.08 vs 0.30 ± 0.15 mm Hg/ml, p = 0.01) and lower RV Ees/Ea (0.37 ± 0.14 vs 1.20 ± 0.54, p < 0.001) versus reference subjects. Low RV Ees correlated with reduced RV septal strain, an indicator of septal contractility, in both the entire cohort (r = 0.68, p = 0.004) as well as the LVAD cohort itself (r = 0.78, p = 0.02). LVAD recipients with low RV Ees/Ea (below the median value) demonstrated more clinical heart failure (71% vs 17%, p = 0.048), driven by an inability to augment RV Ees (0.22 ± 0.11 vs 0.19 ± 0.02 mm Hg/ml, p = 0.95) to accommodate higher RV Ea (0.82 ± 0.38 vs 0.39 ± 0.08 mm Hg/ml, p = 0.002). Pulmonary artery pulsatility index (PAPi) best identified low baseline RV Ees/Ea (≤0.35) in LVAD patients ((area under the curve) AUC = 0.80); during the ramp study, change in PAPi also correlated with change in RV Ees/Ea (r = 0.58, p = 0.04).
LVAD patients demonstrate occult intrinsic RV dysfunction. In the setting of excess RV afterload, LVAD patients lack the RV contractile reserve to maintain ventriculo-vascular coupling. Depression in RV contractility may be related to LVAD left ventricular unloading, which reduces septal contractility.
Preoperative and mid-term right ventricular systolic function assessment, at rest and during exercise, with speckle-tracking echocardiography after left ventricular assist device implantation
2024, Hellenic Journal of Cardiology
The study aimed to compare pre- and postoperative resting as well as postprocedural resting and exertional right ventricular speckle-tracking echocardiographic parameters at a mid-term follow-up after left ventricular assist device (LVAD) implantation.
Patients with implanted third-generation LVADs with hydrodynamic bearings were prospectively enrolled (NCT05063006). Myocardial deformation was evaluated before pump implantation and at least three months after the procedure, both at rest and during exercise.
We included 22 patients, 7.3 months (IQR, 4.7-10.2) after the surgery. The mean age was 58.4 ± 7 years, 95.5% were men, and 45.5% had dilated cardiomyopathy. The RV strain analysis was feasible in all subjects both at rest and during exercise. The RV free wall strain (RVFWS) worsened from −13% (IQR, −17.3 to −10.9) to −11.3% (IQR, −12.9 to −6; p = 0.033) after LVAD implantation with a particular decline in the apical RV segment [-11.3% (IQR, −16.4 to −6.2) vs −7.8% (IQR, −11.7 to −3.9; p = 0.012)]. The RV four-chamber longitudinal strain (RV4CSL) remained unchanged [-8.5% (IQR, −10.8 to −6.9) vs −7.3% (IQR, −9.8 to −4.7; p = 0.184)]. Neither RVFWS (−11.3% (IQR, −12.9 to −6) vs −9.9% (IQR, −13.5 to −7.5; p = 0.077) nor RV4CSL [−7.3% (IQR, −9.8 to −4.7) vs −7.9% (IQR, −9.8 to −6.3; p = 0.548)] changed during the exercise test.
In patients who are pump-supported, the right ventricular free wall strain tends to worsen after LVAD implantation and remains unchanged during a cycle ergometer stress test.
Optimizing Hemodynamic Interventricular Interactions in LVAD Recipients: Is Speed Everything?
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Impact of Interventricular Interaction on Ventricular Function: Insights From Right Ventricular Pressure-Volume Analysis
2024, JACC: Heart Failure
Interventricular interactions may be responsible for the decline in ventricular performance observed in various disease states that primarily affect the contralateral ventricle.
This study sought to quantify the impact of such interactions on right ventricular (RV) size and function using clinically stable individuals with left ventricular assist devices (LVADs) as a model for assessing RV hemodynamics while LV loading conditions were acutely manipulated by changing device speed during hemodynamic optimization studies (ie, ramp tests).
The investigators recorded RV pressure-volume loops with a conductance catheter at various speeds during ramp tests in 20 clinically stable HeartMate3 recipients.
With faster LVAD speeds and greater LV unloading, indexed RV end-diastolic volume increased (72.28 ± 15.07 mL at low speed vs 75.95 ± 16.90 at high speed; P = 0.04) whereas indexed end-systolic volumes remained neutral. This resulted in larger RV stroke volumes and shallower end-diastolic pressure-volume relationships. Concurrently, RV end-systolic pressure decreased (31.58 ± 9.75 mL at low speed vs 29.58 ± 9.41 mL at high speed; P = 0.02), but contractility, as measured by end-systolic elastance, did not change significantly. The reduction in RV end-systolic pressure was associated with a reduction in effective arterial elastance from 0.65 ± 0.43 mm Hg/mL at low speed to 0.54 ± 0.33 mm Hg/mL at high speed (P = 0.02).
Interventricular interactions resulted in improved RV compliance, diminished afterload, and did not reduce RV contractility. These data challenge the prevailing view that interventricular interactions compromise RV function, which has important implications for the understanding of RV-LV interactions in various disease states, including post-LVAD RV dysfunction.
Value of Invasive Hemodynamic Assessments in Patients Supported by Continuous-Flow Left Ventricular Assist Devices
2024, JACC: Heart Failure
Left ventricular assist devices (LVADs) are increasingly used in patients with end-stage heart failure (HF). There is a significant risk of HF admissions and hemocompatibility-related adverse events that can be minimized by optimizing the LVAD support. Invasive hemodynamic assessment, which is currently underutilized, allows personalization of care for patients with LVAD, and may decrease the need for recurrent hospitalizations. It also aids in triaging patients with persistent low-flow alarms, evaluating reversal of pulmonary vasculature remodeling, and assessing right ventricular function. In addition, it can assist in determining the precipitant for residual HF symptoms and physical limitation during exercise and is the cornerstone of the assessment of myocardial recovery. This review provides a comprehensive approach to the use of invasive hemodynamic assessments in patients supported with LVADs.
The Need for Speed: Modulating Continuous-Flow LVAD Responsiveness During Exercise for Patients With Heart Failure
2024, JACC: Heart Failure

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View full text

Right ventricular function and cardiopulmonary performance among patients with heart failure supported by durable mechanical circulatory support devices

BACKGROUND

METHODS

RESULTS

CONCLUSIONS

Section snippets

Patient population

Subject characteristics

Effect of CF-LVAD pump speed modulations on RV function

Discussion

Conclusions

Disclosure statement

J Heart Lung Transplant

J Heart Lung Transplant

J Heart Lung Transplant

J Am Soc Echocardiogr

JACC Heart Fail

J Heart Lung Transplant

J Am Coll Cardiol

J Heart Lung Transplant

Two-year outcomes with a magnetically levitated cardiac pump in heart failure

N Engl J Med

Intrapericardial left ventricular assist device for advanced heart failure

N Engl J Med

Stroke incidence and impact of continuous-flow left ventricular assist devices on cerebrovascular physiology

Stroke

Assessment of right ventricular function in left ventricular assist device candidates

Circ Cardiovasc Imaging

Right ventricular dysfunction in systemic sclerosis-associated pulmonary arterial hypertension

Circ Heart Fail

Right ventricular functional reserve in pulmonary arterial hypertension

Circulation

Load-independent systolic and diastolic right ventricular function in heart failure with preserved ejection fraction as assessed by resting and handgrip exercise pressure-volume loops

Circ Heart Fail

New insights into resting and exertional right ventricular performance in the healthy heart through real-time pressure-volume analysis

J Physiol