Impact of postoperative blood pressure control on regression of left ventricular mass following valve replacement for aortic stenosis

Abstract

Considerable left ventricular (LV) hypertrophy sometimes remains after aortic valve replacement (AVR) for aortic stenosis. For this issue, most previous studies have focused solely on transprosthetic pressure gradient, although true problem is not the pressure gradient itself but an elevated LV pressure. This study investigated the impact of blood pressure on postoperative LV mass regression, which had been overlooked in previous studies. Seventy-nine adult patients with pure aortic stenosis who were treated with AVR using bileaflet mechanical valves underwent echocardiography before surgery, around 6 months later ('early'), and 2-3 years later (31.7+/-14.7 months, 'late'). Patients were divided into two groups whether postoperative systolic blood pressure was below (n=47; N group) or above 130 mmHg (n=32; H group) following recommendation of WHO-ISH and JNC 7th report. Preoperative LV mass (g/m2) did not differ significantly (232+/-80 vs. 243+/-76, P=0.91). LV mass became significantly smaller and regression was significantly more effective in N group than in H group both at 'early' (145+/-43 vs. 180+/-54, regression against preoperative value 34.6+/-19.1 vs. 19.9+/-26.6%, P=0.007) and 'late' (132+/-41 vs. 178+/-51, regression 41.1+/-16.0 vs. 21.0+/-27.0%, P<0.001) evaluations. Regression between 'early' and 'late' evaluations was significant only in N group (P=0.012). The LV mass index returned to the normal range at 'late' evaluation in 52.1% of N group and 12.5% of H group patients (P<0.001), and 25 out of 29 patients without residual LV hypertrophy were N group patients. Multivariate analyses revealed that preoperative LV mass index (P<0.001) and postoperative systolic blood pressure (P=0.007) showed significant influence on postoperative LV mass index, and postoperative systolic blood pressure alone significantly (P<0.001) influenced the regression ratio of the LV mass against the preoperative value. No prosthesis related variables (size, orifice area index, pressure gradient) had significant influence. For LV mass regression after AVR, postoperative blood pressure appeared to be more important than prosthesis selection. Controlling the systolic blood pressure below 130 mmHg was beneficial, which coincided with recommendation of WHO-ISH and JNC 7th report despite the pressure drop due to prosthesis in the aortic position.