Hypotensive Response on Cardiopulmonary Stress Test Predicts Elevated Pulmonary Capillary Wedge Pressure and Reduced Cardiac Output in Patients Undergoing Evaluation for Left Ventricular Assist Device

Abstract

Purpose Cardiopulmonary stress test (CPX) and right heart catheterization (RHC) are integral part of the routine evaluation for ventricular assist device (LVAD) therapy. A hypotensive response, or failure to augment systolic blood pressure at peak stress above resting values might be a marker of high-risk physiology. We sought to evaluate the association between hypotensive response on CPX and invasive hemodynamics in patients undergoing LVAD evaluation. Methods This was a retrospective single center study of consecutive adult patients who underwent LVAD surgery at our center between 1/2011 and 1/2019. Only patients with both CPX and RHC performed within 12 months of implantation were included. Hypotensive response was defined as a peak exercise systolic blood pressure lower than the resting systolic blood pressure. Central venous pressure (CVP), pulmonary capillary wedge pressure (PCWP) and cardiac index determined using the thermodilution method (CI) were collected from RHC data. Multivariable Cox regression analysis was performed to evaluate the association between CPX data and hemodynamics. Results A total of 313 patients were included in the study and 115 met inclusion criteria. The mean age was 60.1 years, 66% were designated bridge to transplant (BTT) and the majority (85%) were classified as INTERMACS 3-5. Forty seven percent (54/115) developed a hypotensive response during testing. The group had a mean PCWP of 23.7 mmHg and a mean CI of 1.7 L/min/m2. In contrast, patients with normal blood pressure response had a significantly lower PCWP (19.8 mmHg; P=0.011) and significantly higher CI (2.0 L/min/m2; p=0.030). There was no difference in CVP values between the groups. Mean exercise duration was 6 minutes and 1 seconds in the hypotensive group, and 7 minutes 8 seconds in the group with normal blood pressure response. Conclusion A hypotensive response on CPX performed prior to LVAD implantation is associated with more severely abnormal hemodynamics. Identification of this high risk feature earlier has the potential to improve outcomes by preventing late LVAD implantation.