Prognostic Value of Pressure-Volume Measures in Hemocompatibility-Related Clinical Adverse Events

Abstract

<h3>Purpose</h3> Continuous-flow left ventricular assist device (cf-LVADs) can lead to hemocompatibility-related clinical adverse events (HRAEs) which are largely determined by mechanisms that underpin the pump-patient interaction. We assessed the association of pressure-volume (PV) measures [stroke work (SW) & pump arterial elastance (E_A)] with incidence of HRAEs. <h3>Methods</h3> Using a validated algorithm, brachial-pressure waveforms from oscillometric blood pressure cuff (SphygmoCor Xcel), echocardiography measures and Medtronic HVAD controller data were collected for estimation PV measures within the first 3 months. Patients (all Bridge-To-Transplantation) were divided into low, intermediate and high tertiles for each of SW (n=13, 14, 9) and E_A (n=12, 12, 12). HRAEs, including nonsurgical bleeding (NB), neurological (NE) and thromboembolic events (TE), was followed through a 12-month period post-implant. Hemocompatibility score (HCS) was calculated based on HRAEs in the 1^st year. Comparison between groups were conducted with one-way ANOVAs and Kruskal-Wallis analyses. Kaplan Meier survival analyses determined time-to-event. <h3>Results</h3> 36 HVAD patients (mean age 57±10, 83% males, 69% non-ischemic cardiomyopathy) were included. Baseline demographics and clinical parameters were comparable between SW and E_A tertile groups. Low E_A group had significantly higher rates of HRAEs in the 1^st year compared to intermediate and high groups (p=0.004). HRAE rates were marginally higher in the low SW group (p=0.080). There were no differences in HCS. Survival analysis showed significant differences in distribution of 1-year cumulative HRAE-free probabilities according to E_A tertiles (33.3%, 83.3% and 91.7% for low, intermediate and high E_A respectively, log-rank=0.003). <h3>Conclusion</h3> PV measures offer value in prognostication of LVAD patients. This study highlights the potential importance of assessing afterload and native ventricular contractility in circumventing HRAEs in cf-LVAD patients.