Patient demographics and clinical characteristics are summarized in Table 1. There were significant differences in age (p < 0.0001) and duration of surgery (p = 0.025) between normotensive and hypertensive groups. On arrival at the office, values of all hemodynamic parameters, including SBP, DBP, PR, and RPP, were higher in the hypertensive group than in the normotensive group (p < 0.0001).

Tables 2 and 3 indicate incidences of patients with SBP ≥160 mmHg and RPP ≥12,000 bpm × mmHg, and perioperative hemodynamic changes, respectively. On arrival at the office, 66 patients (62%) in the hypertensive group and 41 patients (10%) in the normotensive group revealed high SBP ≥160 mmHg. Thirty minutes later, SBP declined to less than 160 mmHg in most of the patients in the normotensive group. On the other hand, in 30 patients (33%) in the hypertensive group, high blood pressure on arrival obviously declined to around or less than 160 mmHg, while in the remaining patients in the group who showed a mean SBP of 182.1 ± 13.8 mmHg on arrival, the blood pressure did not clearly decrease after 30 min of rest. Oral nifedipine administered to patients with sustained high blood pressure decreased SBP to 144.7 ± 23.1 mmHg by 28.1 ± 9.3 min after administration, which was similar to that in hypertensive patients without nifedipine.

Although the mean SBP in the hypertensive group was significantly higher than that in the normotensive group during operation, SBP <160 mmHg was maintained in all patients except three in the hypertensive group (2.8%) and one in the normotensive group (0.2%). The values of DBP in patients in the hypertensive group were higher than those in the normotensive group throughout the observation course, and changes in DBP in each group were similar to those in SBP.

On arrival at the office, RPP ≥12,000 bpm × mmHg was found in 74 patients (70%) in the hypertensive group and 111 patients (27%) in the normotensive group. More than 90% of the patients with preoperative nifedipine showed high RPP on arrival at the office. Among patients with high RPP, all patients in the normotensive group, 10% of the patients without nifedipine in the hypertensive group and 35% of patients with nifedipine in the hypertensive group had RPP <12,000 bpm × mmHg until initiation of intravenous sedation. The values of RPP during operation under intravenous sedation were maintained at a normal range except in nine patients (8.5%) in the hypertensive group and one patient (0.2%) in the normotensive group.