Pre- and postoperative antihypertensive treatment with calcium antagonist in pheochromocytoma

Medical preparation for pheochromocytoma surgery requires adrenergic blockade and restoration of euvolemia. Usually, this preoperative preparation consisted essentially of sequential and progressive adrenergic antagonism, alpha then beta blockade. This therapy is not easy to introduce and exposes to blood pressure collapses after tumor removal. By contrast, calcium channel blocking drugs like dihydropyridines offer efficacy and safety. Moreover, new intravenous (IV) agents (nicardipine, diltiazem) provide useful therapeutic tools to control, rapidly and with a dose-dependent effect, any undesired hemodynamic event during surgery. As a demonstration of this new therapeutic strategy for management of pheochromocytoma resection, we report here the cases of two patients who were exclusively treated with dihydropyridines. A 61 year-old woman and a 41 year-old man were scheduled for pheochromocytoma resection (left and right adrenal tumors, respectively). Both patients received dihydropyridines for preoperative preparation (nicardipine and nifedipine, respectively, 60 mg/day). This treatment allowed a good control of arterial blood pressure (BP) (from 210/110 to 170/90 and 180/100 to 140/80 mmHg, respectively) and was maintained up to the morning of the operative day. After patient installation on the operating-table, IV nicardipine infusion was started (2 mg/hour). Anesthesia consisted of high doses of fentanyl, flunitrazepam and vecuronium. Hemodynamic measurements (radial artery and Swan ganz catheters) allowed adjustment of nicardipine infusion rate to maintain peripheral arterial resistances under 1,000 dynes.s.cm-5, and adequate volume loading. A hypertensive crisis (270/130 mmHg) occurred at the time of the intubation in the first case but responded to higher infusion rate of nicardipine (5 mg/10 min).(ABSTRACT TRUNCATED AT 250 WORDS)