Chronic AT1-receptor blockade does not alter cerebral oxygen supply/demand ratio during cardiopulmonary bypass in hypertensive patients

• Published in: Acta anaesthesiologica Scandinavica 2008-01, Vol.52 (1), p.73-80
• Main Authors: KOTTENBERG-ASSENMACHER, E., MASSOUDY, P., JAKOB, H., PHILIPP, T., PETERS, J.
• Format: Article
• Language: English
• Subjects: Aged; Anesthesia; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Angiotensin II receptor type 1 antagonist; Angiotensin II Type 1 Receptor Blockers - pharmacology; Angiotensin II Type 1 Receptor Blockers - therapeutic use; Antihypertensive Agents - pharmacology; Antihypertensive Agents - therapeutic use; Arterial hypertension. Arterial hypotension; Benzimidazoles - pharmacology; Benzimidazoles - therapeutic use; Biological and medical sciences; Blood and lymphatic vessels; Blood Flow Velocity - drug effects; Blood Pressure - drug effects; Brain - metabolism; Cardiology. Vascular system; Cardiopulmonary Bypass - adverse effects; cerebral arterial-jugular bulb oxygen content difference; Cerebral Arteries; cerebral perfusion; Cerebrovascular Circulation - drug effects; Double-Blind Method; Female; Humans; Hypertension - complications; Hypertension - drug therapy; Hypoxia, Brain - etiology; Hypoxia, Brain - prevention & control; Intraoperative Complications - etiology; Intraoperative Complications - prevention & control; Jugular Veins; Male; Medical sciences; Middle Aged; Middle Cerebral Artery; middle cerebral artery blood velocity; Oxygen - metabolism; Phenylephrine - administration & dosage; Phenylephrine - therapeutic use; Premedication; Tetrazoles - pharmacology; Tetrazoles - therapeutic use; Treatment Failure
• ISSN: 0001-5172; 1399-6576
• DOI: 10.1111/j.1399-6576.2007.01479.x

Background: The angiotensin II receptor type 1 antagonist candesartan has been hypothesized to alter vasopressor requirements and brain–blood flow by changing cerebrovascular autoregulation. Therefore, we assessed the effects of a pre‐anaesthetic treatment course with candesartan on cerebral arterial‐jugular bulb oxygen content difference, middle cerebral artery blood velocity, and vasopressor requirements in hypertensive patients undergoing elective on‐pump coronary artery bypass graft surgery. Methods: In a randomized, double‐blind, placebo‐controlled study, we evaluated the effects of candesartan (8 mg po/d, given for 6–8 days before surgery) in 35 hypertensive patients. The mean arterial pressure was maintained above 60 mmHg by bolus administration of phenylephrine, if required, and dosages were recorded. Results: Candesartan did not significantly alter oxygen content difference across the cerebral circulation, mean middle cerebral artery blood velocity during cardiopulmonary bypass, or phenylephrine requirements either before (0.0067 μg/kg/min±0.0042 vs. 0.0056 μg/kg/min±0.0049, P=0.48) or during cardiopulmonary bypass (0.0240 μg/kg/min±0.0240 vs. 0.0250 μg/kg/min±0.0190, P=0.97) compared with placebo. Conclusion: Thus, a 6–8‐day treatment course with candesartan does not alter global cerebral perfusion and oxygen supply/demand ratio during cardiopulmonary bypass, or vasopressor requirements in hypertensive patients undergoing on‐pump coronary artery bypass graft surgery, and no deleterious consequences of AT1‐receptor blockade were detected.