DELAYED RECOVERY OF MYOCARDIAL PERFUSION IN ACUTE MYOCARDIAL-INFARCTION - A SCINTIGRAPHIC STUDY AFTER EARLY THROMBOLYTIC TREATMENT

Background Assessments of compromised myocardium and infarct size earl y after thrombolytic treatment in acute myocardial infarction (AMI) ar e important for risk stratification and for treatment management. We h ave therefore evaluated the clinical usefulness of myocardial perfusio n scintigraphy (MIBI-SPECT) for the assessment of myocardial viability early after AMI. Methods Seventy-one patients [53 men and 18 women, a ged 64 +/- 9 years (range 45-75 years)] with AMI treated by thrombolys is took part in this prospective study at University Hospital, Stockho lm, Sweden. Sixty of them underwent adenosine-stress and resting MIBI- SPECT 2-4 days after AMI, and 11 were examined only at rest. Six month s after the AMI, a repeat MIBI-SPECT at rest was obtained for comparis on. Results All patients had significant perfusion defects compared wi th an age- and sex-matched healthy reference population. Seventy-six p ercent of the patients able to undergo a complete adenosine-stress and rest SPECT showed signs of reversible perfusion defects. Defect size (extent) and severity at rest decreased between the tests at 2-5 days and 6 months after AMI (P < 0.001). Reversible perfusion defects early after AMI were not related to spontaneous improvement of myocardial p erfusion 6 months later. Early, semiquantitative MIBI-SPECT was not ab le to predict final infarct size as measured by resting perfusion data 6 months after AMI, regardless of whether the threshold value was set at 30, 40, 50 or 60% of the maximal isotope uptake in the early resti ng scan. Conclusions Myocardial perfusion scintigraphy with adenosine- stress and resting MIBI-SPECT early after AMI underestimates myocardia l viability in the majority of patients treated with thrombolytic agen ts. Neither reversible perfusion defects nor regional semiquantitative perfusion data appear to predict spontaneous improvement of perfusion 6 months after AMI. Coronary Artery Dis 9:443-449 (C) 1998 Lippincott Williams & Wilkins.