Effect of myocardial revascularisation on left ventricular systolic function in patients with and without viable myocardium: should non-viable segments be revascularised?

OBJECTIVE: To assess the effect of surgical revascularisation on left ventricular (LV) systolic function in patients with viable and non-viable dysfunctional LV segments determined by low dose dobutamine stress echocardiography (DSE). DESIGN: Prospective observational cohort study. SETTING: Single tertiary care centre. PATIENTS: Consecutive patients referred to surgical revascularisation (n=115). INTERVENTIONS: DSE and surgical revascularisation. MAIN OUTCOME MEASURES: Functional recovery defined as increase in ejection fraction ≥ 5% 1 year after revascularisation in patients with and without viable myocardium (viability defined as improvement of contractility in ≥ 4 LV segments on DSE). RESULTS: The mean age, ejection fraction and wall motion score index (WMSi) of patients were 59 ± 9 years, 44 ± 9% and 1.82 ± 0.31, respectively. There was no difference between DSE positive and DSE negative patients for any of those parameters at baseline study (p>0.05 for all). After 12 months, the ejection fraction increased 11 ± 1% in patients with viable myocardium vs 7 ± 1% in patients without viable myocardium (p=0.002). Moreover, in patients with viable myocardium, the greatest increase of ejection fraction occurred 1 month after surgery (9 ± 1%), whereas in those patients with negative DSE the ejection fraction increased more gradually (2±1% after 1 month, p=0.002 between groups for 1 month vs preoperative value), but still improved after 12 months follow-up (p<0.0001 in time for both groups). CONCLUSIONS: It appears that patients with LV dysfunction, but without viable myocardium, may also benefit from myocardial revascularisation. Functional recovery continuously occurs throughout the first year after surgical treatment.