Outcomes based on blood pressure in patients on continuous flow left ventricular assist device support: An Interagency Registry for Mechanically Assisted Circulatory Support analysis

Abstract

An optimal blood pressure (BP) range to mitigate morbidity and mortality on left ventricular assist device (LVAD) support has not been clearly defined. Average Doppler opening pressure, mean arterial pressure (MAP), and/or systolic blood pressure (SBP) were calculated in operative survivors (n = 16,155) of LVAD support in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). BP distributions were used to group patients into low (BP <25th percentile), normal (25-75th percentile), high (75th-95th percentile), and very high (>95th percentile). Associations between BP and adverse events were evaluated using Cox regression (hazard ratio[HR], 95% confidence interval). The median (25th, 75th) MAP, Doppler, and SBP (mm Hg) during continuous flow LVAD support were 84 (77, 90), 85 (80, 92), and 99 (90, 107) mm Hg, respectively. BP had a bimodal risk association with survival. At 3 years, survival was 58% ± 1.8%in those with low MAP (≤75 mmHg) vs 70% ± 0.9%, 71% ± 1.5%, and 63% ± 3.0%in the those with normal, high, or very high average MAP, respectively. Patients with chronically low MAP (≤75 mmHg), Doppler (≤80 mmHg), and SBP (<90 mmHg) had 35%-42% higher adjusted hazards of death than patients with normal or high BP (p ≤ 0.0001). Patients with MAP >100 mmHg, Doppler ≥105 mmHg, and SBP ≥120 mmHg had 17%-20% higher adjusted hazards of death than those with normal pressures (p < 0.05). In patients on axial flow LVADs, elevated SBP (HR 1.08 [95% confidence interval, 1.04-1.13] per 10 mmHg increase) but not MAP correlated with increased incident of stroke. In INTERMACS, BP extremes during LVAD support increase the risk for adverse events, supporting a MAP goal >75 mmHg and <90 mmHg. Hypotension conferred the highest risk for mortality. Excessive BP control should be avoided, and Doppler opening pressure should not be assumed to represent MAP in all patients.