Impact of Chronic Heart Failure on Vascular Responsiveness: A Prospective Observational In Vivo and Ex Vivo Study in Patients Undergoing Cardiac Surgery

Background: Patients with chronic heart failure (HF) are at increased risk of vasoplegia after cardiac surgery, potentially because neurohormonal activation in the context of HF alters vascular regulation. Methods: We compared perioperative vasoresponsiveness in patients with and without HF undergoing cardiac surgery with cardiopulmonary bypass (CPB). Patients were prospectively enrolled, and changes in systemic vascular resistance (ΔSVR) after phenylephrine and nitroglycerin were measured perioperatively (in vivo). Ex vivo vasoreactivity to phenylephrine and vasopressin was tested in 40 biopsies. Results: In vivo and ex vivo analyses included 36 and 13 patients (10 controls and 3 HF patients), respectively. At baseline, phenylephrine increased SVR by 26% in HF patients (estimated marginal mean, 95% CI 16–35%) versus 51% in controls (95% CI 38–64%; p = 0.002). This attenuated response persisted during CPB, and ex vivo observations suggested a similar pattern. Responsiveness to nitroglycerin was unchanged. Lower post-CPB ΔSVR was associated with greater norepinephrine use during the first postoperative day (β = −346.6, 95% CI −541.2 to −151.9; R2 = 0.291). Conversely, HF patients showed greater ex vivo responsiveness to vasopressin. Conclusions: HF is associated with marked impairment of α1-adrenergic vasoresponsiveness, indicating impaired α1-adrenergic signaling. Preserved vasopressin responsiveness may support its earlier use for postoperative hypotension in these patients.