MYOCARDIAL PERFUSION AFTER CORONARY-ARTERY BYPASS-SURGERY - A STUDY USING ECTOMOGRAPHIC MYOCARDIAL SCINTIGRAPHY AND ADENOSINE PROVOCATION

A study was conducted to determine the time dependency of myocardial p erfusion improvement after coronary artery bypass graft (CABG) surgery . Seventeen 3-vessel diseased patients (16 male, 1 female) scheduled f or CABG surgery from a cardiac surgical and intensive-cart unit were e xamined. Ten of the 17 patients returned for examination after 1 year. A titrated adenosine infusion was used to expose reversible ischemia. Tc99m-sestamibi was injected at rest and at maximum adenosine infusio n rate, and isotope distribution was determined using ectomographic my ocardial scintigraphy. Visually scored percent isotope uptake defect s ize and percent uptake reduction were assessed. It was found that rest ing isotope uptake defects were unchanged 1 h after surgery, increased in severity after 1 week, and after 1 year were 24% less than the pre operative scores (p < 0.01) and 55% less than after 1 week (p < 0.001) . It was found that adenosine infusion induced a 57% increase in avera ge defect score preoperatively (p < 0.001) but no increase postoperati vely. No differences were seen between regions supplied by arterial or venous grafts. Isotope uptake defects increased between 1 h and 1 wee k after CABG surgery, and after 1 year the scores were less than those recorded preoperatively and after 1 week. Adenosine-induced reversibl e isotope uptake changes seen preoperatively were eliminated postopera tively in all vessel regions.