The effect of mild left ventricular diastolic dysfunction on outcome after isolated coronary bypass surgery

BACKGROUND: Although moderate to severe diastolic dysfunction (DD) seems to be associated with poor prognosis after isolated coronary bypass surgery, the impact of mild DD has not been investigated extensively in this group of patients. AIM: We evaluated the prognostic implication of mild left ventricular (LV) DD on outcome after isolated coronary bypass surgery in patients with preserved LV systolic function. METHODS: Data from 650 patients undergoing isolated coronary bypass surgery and having records for LV diastolic function between January 2009 and August 2011 was collected retrospectively. DD was classified as mild (grade 1, impaired relaxation), moderate (grade 2, decreased compliance) or severe (grade 3-4, restrictive pattern) depending on mitral inflow wave, tissue Doppler imaging, and pulmonary vein flow wave. Patients with baseline rhythm other than sinus, moderate or severe valvular dysfunction, moderate or severe diastolic dysfunction, and LV ejection fraction lower than 50% were excluded. A total of 472 patients were identified within the database fulfilling the eligibility criteria for this analysis and stratified according to the echocardiographic findings as follows: group 1 comprised patients with normal diastolic function (n = 168); and group 2 was made up of patients with mild DD (impaired relaxation) (n = 304). These groups were compared for perioperative morbidity and mortality. RESULTS: The preoperative variables were comparable between groups. The outcome parameters of group 1 was similar compared to group 2 in terms of need for inotropic support (20.2% vs. 16.2%), intra-aortic balloon pump usage (0% vs. 1.4%), mechanical ventilation time (8.94 ± 0.96 h vs. 10.0 ± 0.89 h), reintubation rate (1.8% vs. 1.4%), intensive care unit stay time (24.1 ± 1.4 hvs. 26.2 ± 1.9 h), postoperative renal failure rate (0% vs. 0.3%), postoperative atrial fibrillation rate (10.1% vs. 11.2%), length of hospital stay (7.19 ± 0.45 vs. 6.57 ± 0.14 days), hospital readmission rate (3.1% vs. 3.1%), and mortality (0% vs. 1.6%). CONCLUSIONS: The results from this study indicate that mild LV DD is not associated with adverse outcome after coronary bypass surgery in patients with preserved LV systolic function, thus should not be considered as a preoperative risk factor.