Clinical utility of early postoperative cardiac multidetector computed tomography after coronary artery bypass grafting

Abstract

We evaluated the clinical utility of early postoperative cardiac computed tomography (ct) for evaluating left ventricular (LV) function and predicting prognosis in patients who had undergone coronary artery bypass grafting (CABG). Of the 205 patients who underwent CABG from March 2011 to December 2014, 136 underwent early postoperative cardiac CT (within 30 days after CABG) and were enrolled as the study population. The baseline and postoperative follow-up echocardiographic findings, major adverse cardiac events (MACE), and death were recorded for a follow-up period (mean, 5.9 ± 1.1 years). functional cardiac ct parameters were compared to echocardiographic measurements. the associations between cardiac CT findings and functional recovery and prognosis were evaluated by logistic regression analyses. The LVEF measured via cardiac CT was significantly higher (56.2 ± 11.5% vs. 61.9 ± 12.9%; p = 0.0002) compared to those via early postoperative echocardiography, but the wall motion score index (WMSI) was not significantly different (1.23 ± 0.33 vs. 1.21 ± 0.28, p = 0.5041) between the two methods. During the follow-up period, 17 patients (12.5%) died and 40 (29.4%) developed MACE. Both the LVEF and WMSI measured with early postoperative echocardiography (p = 0.0202 and odds ratio [OR] = 5.0171, p = 0.0039, respectively), and cardiac CT (OR = 0.9625, p = 0.0091 and OR = 14.3605, p = 0.0001, respectively) predicted MACE OR = 0.9630, but only the WMSI, measured using cardiac CT, predicted all-cause death (OR = 10.6017, p = 0.0035). In CABG patients, LVEF and the WMSI measured with early postoperative cardiac CT were comparable with echocardiography and predicted the development of MACE and all-cause death. Coronary artery bypass grafting (CABG) restores myocardial contractile function in patients with multi-vessel coronary artery disease 1,2 , but this is not always effective 3,4. Global ischemia and superimposed reperfusion injury might have deleterious effects on the heart 5-7. Moreover, the time course of functional recovery after CABG varies from immediately intra-operatively to 1 year postoperatively 7-11. Therefore, monitoring cardiac function in patients who have undergone CABG is important to predict their clinical outcome. Early anatomical recognition of bypass graft failure is important in terms of predicting clinical outcomes after CABG 12-15. Computed tomography (CT) is a powerful noninvasive technique providing anatomical information on graft patency, with simultaneous evaluation of cardiac function without any need for additional examination 16. Several studies have shown that CT is comparable to echocardiography and MRI for assessment of global left ventricular (LV) function and regional wall motion 17,18. Moreover, CT is quicker and easier to perform than MRI, which makes it suitable for the examination of patients who have recently undergone CABG.