INCREASED RISK OF CORONARY-ARTERY BYPASS-GRAFTING FOR LEFT-VENTRICULAR DYSFUNCTION WITH DILATED LEFT-VENTRICLE

The operative mortality and morbidity in patients with severe left ven tricular dysfunction who undergo coronary artery bypass grafting (CABG ) remain high, The low ejection fraction is the major risk factor for operative mortality, However, ejection fraction (EF) alone may not nec essarily be an accurate predictor of operative mortality, We studied t he correlation between indices of left ventricular volume and operativ e mortality, One thousand patients undergoing isolated coronary bypass operations were divided into three groups according to their preopera tive ejection fraction, Fifty patients (group I) had severe left ventr icular dysfunction (EF less than or equal to 0.3), 56 patients (group II) had moderately left ventricular dysfunction (0.3 < EF less than or equal to 0.4) and 894 patients (group III) had good left ventricular function (EF > 0.4). We analyzed the relationship between hospital mor tality and left ventricular volume in 106 patients with an EF less tha n or equal to 0.4. Results. Cardiac index was not significantly differ ent among the three groups, The left ventricular end-diastolic pressur e (LVEDP) and mean pulmonary artery pressure in groups I an II were hi gher than those in group III, The left ventricular end-diastolic volum e (LVEDV) was 146 +/- 44 ml/m(2) in Group I, 112 +/- 31 ml/m(2) in Gro up II and 82 + 30 ml/m(2) in Group III, respectively (Group I versus I I, p < 0.05, Group I and II versus III, p < 0.01). The left ventricula r end-systolic volume (LVESV) was 111 +/- 38 ml/m(2) in Group I, 72 +/ - 21 ml/m(2) in Group II and 30 +/- 14 ml/m(2) in Group III, respectiv ely (Group I versus II, p < 0.05, Group I and II versus III, p < 0.01) , The LVEDV and LVESV were higher in Group I than in Group II and both in Groups I and II were higher than in Group m. The hospital mortalit y of any cause before discharge was 8.0% (4/50) in Group I, 3.6% (2/56 ) in Group II, and 2.0% (18/894) in Group III, The mortality in Group I was higher than that in Group III, but the mortality between Groups I and II was not different. We assessed correlations between large lef t ventricle with left ventricular dysfunction and operative mortality in 106 patients with ejection fractions of less than or equal to 0.4, The hospital mortality in patients with both under fraction 0.4 and an LVESV greater than or equal to 140 ml/m(2) was 50% (4/8). This rate w as higher than in patients with an LVESV between 80 and 140 ml/m(2) (1 .8% 1/55) (p = 0.0006) and an LVESV less than 80 ml/m(2) (2.3%, 1/43), (p = 0.0013). The hospital mortality in patients with an LVEDV greate r than or equal to 200 ml/m(2) was 67% (4/6), It was also higher than that in patients with an LVEDV between 200 and 120 ml/m(2) (1.7%, 1/58 ), (p = 0.0001), and an LVEDV less than 120 ml/m(2) (2.4%, 1/42), (p = 0.0004). We conclude that patients with a low ejection fraction and a n elevated LVESV or LVEDV are at increased risk for hospital death fol lowing CABG.