The Use of Ketanserin, a 5-Hydroxytryptamine Receptor Antagonist, for Treatment of Postoperative Hypertension Following Coronary Artery Bypass Surgery

Abstract

In patients developing hypertension following coronary artery bypass surgery (CABG) the possible role of 5-hydroxytryptamine (5-HT; serotonin) was investigated by injecting ketanserin, a specific 5-HT2-receptor antagonist. Ketanserin was administered intravenously when intraarterial systolic blood pressure (SAP) exceeded 150 mm Hg either as a 10-mg bolus (group 1, N = 15), or as a 10-mg bolus followed by infusion of 4 mg/h for either 2.5 h (group 2, N = 15) or for 1 h (group 3, N = 10). In 33 patients (82.5%), SAP and diastolic arterial pressure decreased significantly within 5 min after the 10-mg bolus. In group 1, SAP gradually increased after 30-50 min but in groups 2 and 3 SAP remained normal. The triple index (TI) decreased significantly in all groups. Heart rate decreased slightly but significantly in groups 2 and 3. Central venous and left atrial pressures did not change substantially in any of the three groups. Cardiac output increased significantly (0.51 +/- 0.158 L/min); hence, systemic vascular resistance (SVR) decreased significantly (452.1 +/- 50.57 dyn . s . cm-5--group 3). No rebound increase in SAP occurred after terminating the infusions (groups 2 and 3). These findings indicate that 5-HT plays a role in the majority of patients who develop hypertension following CABG. The decrease of SVR without reflex tachycardia is a favorable effect of ketanserin.