The role of implantable cardioverter defibrillators in high-risk CABG patients identified early post-cardiac surgery

Abstract

To assess clinical markers that can be used in predicting the outcome and role of implantable cardioverter defibrillators (ICD) in coronary artery bypass surgery (CABG) patients with severely depressed left ventricular ejection fraction (LVEF), independent of time from revascularization. The database was searched for patients who had CABG surgery and had an ICD within 4 months of surgery, between 1999 and 2005. The records were reviewed for LVEF, status of revascularization, programmed electrical stimulation results, and medications. The primary endpoints were: combined total mortality (TM) and appropriate ICD therapy (ICD-T), and the individual outcomes of TM and ICD-T. One hundred and sixty-four patients were identified, 69 had an ICD implanted for primary prevention of sudden cardiac death and were followed till June 2009. The mean pre- and post-operative LVEFs were 29 and 33%, 46 (67%) had incomplete revascularization, and 38 (55%) had inducible ventricular arrhythmias. Over the mean follow-up of 40 months, 20 patients (29%) died and 18 (26%) had ICD-T. In the Cox proportional hazard model, the following variables were significant at the 0.05 level; for the combined outcome TM and ICD-T: congestive heart failure (CHF) class III/IV and coronary artery disease (CAD) + valvular disease; for ICD-T outcome: CAD + valvular disease; for TM outcome: female gender, LVEF < 35%, CHF class III/IV, and lack of angiotensin converting enzyme-inhibitor therapy. Clinical assessment of CABG patients can assist in selecting a high-risk group with TM and ICD-T rates comparable to those of primary prevention studies and could be useful for future randomized ICD studies in this selective group of patients.