Andrew Mihalek, MD
Associated Profressor of Pulmonology
University of Virginia, United States
Disclosure information not submitted.
Matthew Morrisette, pharmD
Critical Care Clinical Pharmacist
University of Virginia, United States
Disclosure information not submitted.
Title: Outcomes of Angiotensin II in Patients with Post-Operative Vasoplegic Syndrome: A Cases Series
Introduction: Post-operative vasoplegic syndrome (PVS) occurs between 8-26% of patients following cardiopulmonary bypass surgery (CPB). PVS is characterized by high cardiac output and low systemic vascular resistance (SVR) in the absence of competing causes of distributive shock. Catecholamine-resistant PVS can be particularly devastating and few vasoactive agents have demonstrated patient-center outcomes. A synthetic form of angiotensin II (ATII) has shown promise in increasing mean arterial pressure and norepinephrine dosage in this setting.
Methods: In this retrospective case series we analyzed the use of ATII between June 2019 and November 2020. Of the 33 patients in which ATII was used, six had a clinical picture consistent with PVS, defined as an SVR of < 820 dynes/cm5 AND a cardiac index of >2.2 L/min/m2 in the setting of recent (< 48 hr) exposure to CPB. Cases in which significant hemorrhage, under-resuscitation, or inadequately treated septic shock occurred were omitted from the analysis. Patients were analyzed for three outcomes: change in creatinine over 72 hours, change in lactate over 12 hours, and change in background norepinephrine (NE) equivalents over 48 hours.
Results: Results were mixed across the study population. The majority of patients had variables that followed divergent paths. One patient, for example, had a sharp decline in serum lactate and NE equivalents while at the same time had a significant rise in serum creatinine (2.2 mg/dl -- 4.0 mg/dl). Only a single patient demonstrated unidirectional change across all three variables. Taken as a whole, lactate levels and NE equivalents decreased in the majority of patients and serum creatinine levels were reduced by half. Additionally, all patients successfully met their individual MAP goal within 6 hours, however only half of the patients survived till hospital discharge.
Conclusions: In this case series of angiotensin II in patients with post-operative vasoplegic syndrome, markers of tissue perfusion, and background NE equivalents had variable results. Despite each patient achieving their individualized MAP goal and the majority showing improvements in serum lactate and background NE equivalents, most patient variables changed discordantly and only three out of six patients survived to hospital discharge.