THE IMPACT OF ARTERIAL-HYPERTENSION ON THE RESULTS OF CORONARY-ARTERYBYPASS-GRAFTING

Arterial hypertension is thought to be associated with reduced coronar y vasodilator reserve in the coronary microcirculation. Increased vent ricular mass and coronary arteriolar abnormalities are the dominant fe atures in patients with severe hypertension, while large-vessel corona ry disease is the predominant feature in patients with mild hypertensi on. In the present study we have evaluated how hypertension influences the out conte of coronary artery bypass grafting (CABG), with emphasi s on patients with preoperative left-ventricular ejection fraction (LV EF) less than or equal to 25%. Between Januar 1, 1990 and November 1, 1994, 77 consecutive patients with LVEF less than or equal to 25% (Hyp ertensive, n = 38 [group 1] and normotensive, n = 39 [group II]) under went CABG. During the same time period 2289 patients with LVEF > 25% u nderwent CABG (Hypertensive, n = 870 [group III] and normotensive, n = 1419 [group IV]) and were studied for comparison. Mean age (64 years) , sex distribution (86% men). and other classical risk factors did not differ between the groups. except a higher incidence of insulin-depen dant diabetes in patients with LVEF less than or equal to 25%. There w ere 18% reoperative CABG, 91% of the patients were Canadian Cardiovasc ular Society's (CCS) angina class 3 and 4 preoperatively, 38% had unst able angina, and 35% underwent urgent surgery (within 24 hours of admi ssion). Angiography and operation data did not differ significantly be tween the groups. Hospital mortality in group I was 5.3% and in group II 15.4%, p < 0.008. In group III it was 6.3% and in group IV 2.2%, p < 0.001. Postoperative low cardiac output occurred in 18% (group I) an d 39% (group II), p < 0.05, and only in 5% in groups III and IV, p < 0 .001. Non-fatal myocardial infarction and other postoperative complica tions revealed no group differences. LVEF and CCS class improved from 1 month postoperatively in groups I and II, however, significantly mor e in group I (hypertensives), p < 0.001. Hypertensive patients with po or left-ventricular function preoperative to were found to have a lowe r hospital mortality and incidence of postoperative low cardiac output than normotensiven with LVEF less than or equal to 25%. Hypertensive patients also had a better improvement of their left-ventricular funct ion and CCS class than normotensiven. Left-ventricular hypertrophy and previous myocardial infarction were predictors for mortality in patie nts with LVEF > 25%. Patients with LVEF less than or equal to 25% show ed the same tendency, though not statistically significant.