Malik Shahid, Hegazy H, Refaei A, Elkum N, Zal Halees.
Value of PET scan for semi quantitative assessment of myocardial viability before CABG in Diabetics with severely impaired LV function.
Pak J Cardiol Jan ;17(1):14-24.

Methods: Retrospective analysis of outcome of 28 patients who underwent coronary artery bypass graft surgery between November 2000 and October 2004 at King Faisal Specialist Hospital. All patients had severely impaired left ventricular function as indicated by preoperative echocardiogram. Myocardial viability was assessed using PET scanning before CABG. All segments of decreased perfusion and/or metabolism in the PET scan were re-analysed based on 18 segment model. All patients had post operative clinical evaluation and follow-up echocardiography for assessment of changes in LVEF as an indicator of global LV function. Results: The mean age was 61 ± 11 years. Eighty-five percent were males, 44% had IDDM, and 56% with NIDDM, 63% had hypertension and 63% were with hyperlipidemia. Only 6 patients had prvious revascularization with percutaneous interventions. None of study patients had prior CABG. Mean preoperative left ventricular ejection fraction was 29 ± 9. Indication for surgery was severe angina in 74% of patients and refractory heart failure in the remaining 26%. Eighty-two percent of patients received >3 grafts. Mean hospital stay was 8.7 ± 4 days. Postoperative course was uneventful in 82% of patients. One patient died in postoperative phase from non cardiac causes. The remaining 27 patients were safely discharged home. Mean follow-up duration was 3.5 ± 1.6 years. Seventy-seven percent of patients remained asymptomatic. One patient had VT required ICD implantation. Five patients had ER visits but none required admission and no patient died during follow-up period. Postoperative LVEF improved to 40 ± 9 (P < 0.0001). Multiple regression analysis indicated that the only variable that predicted improvement in global LV function was presence of segments of decreased perfusion and normal metabolism (hibernating segments) at PET scan. It also indicated that the single variable that predicted deterioration of LV function was the number of segments with reduced perfusion and metabolism at PET scan./ Patients with > 4 hibernating myocardial segments had more significant improvement in LVEF compared to those with < 4 viable segments (P= 0.0001). Conclusion: Myocardial PET scan is an accurate and reliable tool for prediction of global LV function recovery with good short and long-term outcomes after surgical revascularization in diabetic patients with extensive CAD and severely impaired preoperative LV function. The presence of > 4 viable segments identified patients who got the maximum improvement in LVEF.

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