Left Ventricular Assist Devices: A Primer for the Non-Mechanical Circulatory Support Provider.

Survival after implant of a left ventricular assist device (LVAD) continues to improve for patients with end-stage heart failure. Meanwhile, more patients are implanted with a destination therapy, rather than bridge-to-transplant, indication, meaning the population of patients living long-term on LVADs will continue to grow. Non-LVAD healthcare providers will encounter such patients in their scope of practice, and familiarity and comfort with the physiology and operation of these devices and common problems is essential. This review article describes the history, development, and operation of the modern LVAD. Common LVAD-related complications such as bleeding, infection, stroke, and right heart failure are reviewed and an approach to the patient with an LVAD is suggested. Nominal operating parameters and device response to various physiologic conditions, including hypo- and hypervolemia, hypertension, and device failure, are reviewed.

A Modified Grading System for Early Right Heart Failure Matches Functional Outcomes and Survival After Left Ventricular Assist Devices.

Early right heart failure (ERHF) remains a common complication after continuous-flow left ventricular assist device (cf-LVAD) and has been associated with increased mortality. The specific criteria used to define ERHF remain somewhat arbitrary. Correlating the degree of ERHF with outcomes after LVAD could inform a more clinically relevant definition. We identified 196 patients who underwent first durable cf-LVAD between 2008 and 2015 at a single center. Postimplant ERHF was graded as absent, mild (requiring inotropic support for 14-20 days), moderate (inotropes for ≥ 21 days), or severe (requiring unplanned RVAD at any time during the index hospitalization). ERHF was associated with clinical outcomes including 1 year survival and New York Heart Association (NYHA) class and 6 minute walk distance (6MWD) at 3 and 6 months. Survival was assessed using the Kaplan-Meier method with log-rank testing and multivariate Cox proportional-hazards modeling. Compared to patients without ERHF, those with mild ERHF had similar 1 year survival (hazard ratio [HR] 0.69, 95% confidence interval [CI]: 0.26-1.80, p = 0.45), while mortality was substantially increased in patients with moderate (HR 2.65, 95% CI: 1.27-5.54, p = 0.009) and severe ERHF (HR 8.16, 95% CI: 3.97-16.76, p < 0.0001). The severity of ERHF was associated with 6MWD at both 3 months (p = 0.001) and 6 months (p = 0.013). The relationship between ERHF and postimplant survival and functional status persisted in multivariate modeling. A simple, modified grading system for ERHF severity is strongly associated with 1 year survival and functional capacity after cf-LVAD. These results argue against using a binary definition for ERHF and suggest the need to modify definition of ERHF severity.

Right ventricular outflow tract velocity time integral-to-pulmonary artery systolic pressure ratio: a non-invasive metric of pulmonary arterial compliance differs across the spectrum of pulmonary hypertension.

Pulmonary arterial compliance (PAC), invasively assessed by the ratio of stroke volume to pulmonary arterial (PA) pulse pressure, is a sensitive marker of right ventricular (RV)-PA coupling that differs across the spectrum of pulmonary hypertension (PH) and is predictive of outcomes. We assessed whether the echocardiographically derived ratio of RV outflow tract velocity time integral to PA systolic pressure (RVOT-VTI/PASP) (a) correlates with invasive PAC, (b) discriminates heart failure with preserved ejection-associated PH (HFpEF-PH) from pulmonary arterial hypertension (PAH), and (c) is associated with functional capacity. We performed a retrospective cohort study of patients with PAH (n = 70) and HFpEF-PH (n = 86), which was further dichotomized by diastolic pressure gradient (DPG) into isolated post-capillary PH (DPG < 7 mmHg; Ipc-PH, n = 54), and combined post- and pre-capillary PH (DPG ≥ 7 mm Hg; Cpc-PH, n = 32). Of the 156 patients, 146 had measurable RVOT-VTI or PASP and were included in further analysis. RVOT-VTI/PASP correlated with invasive PAC overall (ρ = 0.61, P < 0.001) and for the PAH (ρ = 0.38, P = 0.002) and HFpEF-PH (ρ = 0.63, P < 0.001) groups individually. RVOT-VTI/PASP differed significantly across the PH spectrum (PAH: 0.13 [0.010-0.25] vs. Cpc-PH: 0.20 [0.12-0.25] vs. Ipc-PH: 0.35 [0.22-0.44]; P < 0.001), distinguished HFpEF-PH from PAH (AUC = 0.72, 95% CI = 0.63-0.81) and Cpc-PH from Ipc-PH (AUC = 0.78, 95% CI = 0.68-0.88), and remained independently predictive of 6-min walk distance after multivariate analysis (standardized ß-coefficient = 27.7, 95% CI = 9.2-46.3; P = 0.004). Echocardiographic RVOT-VTI/PASP is a novel non-invasive metric of PAC that differs across the spectrum of PH. It distinguishes the degree of pre-capillary disease within HFpEF-PH and is predictive of functional capacity.

Outcomes with prophylactic use of percutaneous left ventricular assist devices in high-risk patients undergoing catheter ablation of scar-related ventricular tachycardia: A propensity-score matched analysis.

BACKGROUND: The PAINESD score predicts the risk of periprocedural acute hemodynamic decompensation (AHD) and postprocedural mortality in patients undergoing catheter ablation (CA) of scar-related ventricular tachycardia (VT). The role of prophylactic placement of percutaneous left ventricular assist devices (pLVADs) in high-risk patients is unknown. OBJECTIVE: The purpose of this study was to evaluate the outcomes of prophylactic use of pLVAD in high-risk patients undergoing CA of scar-related VT. METHODS: We included 75 patients undergoing CA of scar-related VT in whom a prophylactic pLVAD was implanted because of perceived high risk. The control population was a propensity-matched group of 75 patients who did not undergo prophylactic pLVAD placement. The PAINESD score was used for propensity matching. RESULTS: The median PAINESD score was 13 (41% with score ≥15) in the prophylactic pLVAD group and 12 (40% with score ≥15) in the control group. Periprocedural AHD occurred in 5 patients (7%) in the prophylactic pLVAD group and in 17 patients (23%) in the control group (P < .01). The 12-month cumulative incidence of VT was 40% in the prophylactic pLVAD group vs 41% in the control group (P = .97), while the 12-month incidence of death/transplant was 33% vs 66%, respectively (P < .01). In multivariable analysis, left ventricular ejection fraction (HR 0.97, 95% CI 0.95-0.99, P = .03), chronic kidney disease (HR 2.24, 95% CI 1.35-3.72, P < .01), VT recurrence (HR 2.33, 95% CI 1.31-4.14, P < .01), and prophylactic pLVAD (HR 0.28, 95% CI 0.16-0.49, P < .01) were all independently associated with death/transplant. CONCLUSION: Prophylactic pLVAD placement in high-risk patients undergoing CA of scar-related VT is associated with a reduced risk of AHD and death/transplant during follow-up without affecting VT-free survival.

Right ventricular response to pulsatile load is associated with early right heart failure and mortality after left ventricular assist device.

BACKGROUND: Right ventricular (RV) adaptation to afterload is crucial for patients undergoing continuous-flow left ventricular assist device (cf-LVAD) implantation. We hypothesized that stratifying patients by RV pulsatile load, using pulmonary arterial compliance (PAC), and RV response to load, using the ratio of central venous to pulmonary capillary wedge pressure (CVP:PCWP), would identify patients at high risk for early right heart failure (RHF) and 6-month mortality after cf-LVAD. METHODS: During the period from January 2008 to June 2014, we identified 151 patients at our center with complete hemodynamics prior to cf-LVAD. Pulsatile load was estimated using PAC indexed to body surface area (BSA), according to the formula: indexed PAC (PACi) = [SV / (PAsystolic - PAdiastolic)] / BSA, where SV is stroke volume and PA is pulmonary artery. Patients were divided into 4 hemodynamic groups by PACi and CVP:PCWP. RHF was defined as the need for unplanned RVAD, inotropic support ≥14 days or death due to RHF within 14 days. Risk factors for RHF and 6-month mortality were examined using logistic regression and Cox proportional hazards modeling. RESULTS: Sixty-one patients (40.4%) developed RHF and 34 patients (22.5%) died within 6 months. Patients with RHF had lower PACi (0.92 vs 1.17 ml/mm Hg/m2, p = 0.008) and higher CVP:PCWP (0.48 vs 0.37, p = 0.001). Higher PACi was associated with reduced risk of RHF (adjusted odds ratio [adj-OR] 0.61, 95% confidence interval [CI] 0.39 to 0.94, p = 0.025) and low PACi with increased risk of 6-month mortality (adjusted hazard ratio [adj-HR] 3.18, 95% CI 1.40 to 7.25, p = 0.006). Compared to patients with low load (high PACi) and adequate right heart response to load (low CVP:PCWP), patients with low PACi and high CVP:PCWP had an increased risk of RHF (OR 4.74, 95% CI 1.23 to 18.24, p = 0.02) and 6-month mortality (HR 8.68, 95% CI 2.79 to 26.99, p < 0.001). CONCLUSIONS: A hemodynamic profile combining RV pulsatile load and response to load identifies patients at high risk for RHF and 6-month mortality after cf-LVAD.