However, the analysis of concomitant preoperative antihypertensive medication in the patients with pre-existent hypertension revealed a difference with regard to the number of patients who received angiotensin-converting-enzyme (ACE) or AT1 receptor (AR) antagonist before surgery (xenon (11 of 12), isoflurane (7 of 12)). The gene discussed is ACE; the disease is hypertensive disorder.