Vasopressin levels in patients undergoing pulmonary thromboendarterectomy (PTE)

Abstract

Vasopressin is a major determinant of vascular tone during cardiac surgery however vasopressin levels are unknown in patients presenting for pulmonary thromboendarterectomy (PTE) utilizing cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). We performed an observational study in 22 patients with chronic thromboembolic disease undergoing PTE with CPB and DHCA to assess perioperative vasopressin levels. Serum vasopressin levels were assessed using a radioimmunoassay at: 1. baseline before surgery, 2. after anesthetic induction, 3. during CPB, 4. after DHCA, 5. after CPB. In 8 patients, vasopressin was undetectable (< 0.5 pg/mL) at baseline. Vasopressin before and after induction of anesthesia was 1.06 +/− 0.96 (SD) pg/mL and 1.21 +/− 1.54 pg/mL, respectively. During CPB, vasopressin increased to 19.22 +/− 28.22 pg/mL (a 2–30‐fold increase from baseline). Vasopressin remained elevated after DHCA (16.29 +/− 22.71 pg/mL) and after CPB (23.619 +/− 26.29 pg/mL). There were no differences between vasopressin levels during CPB, after DHCA, or after CPB. We conclude that a significant portion of these patients may present for PTE with a relative deficiency of vasopressin. Nevertheless, there is a marked increase from baseline in the secretion of vasopressin at the initiation of CPB and thereafter. Further studies are required to determine if vasopressin secretion in this population is abnormal.