Objective: To assess whether some of the clinical and angiographic variables usually associated with the severity of coronary artery disease could be considered as markers of viability after myocardial infarction.
Patients: We studied 41 patients with previous Q wave infarction and single-vessel coronary artery disease.
Methods: Patients were studied with thallium-201 SPECT, two imaging acquisitions were performed: stress and reinjection three to four hours later under nitroglycerin effect. Perfusion and viability were compared to clinical and angiographic variables, including the degree of patency and colateralization.
Results: In the infarct related area, 66 % of the 177 perfusion defects were considered reversible (definite in 40 %). In patient analysis, 28 patients were considered as having reversibility (18 with definite and 10 with possible reversibility). None of the clinical or stress test variables were significantly associated with reversibility; all these variables had extremely poor negative predictive values and only stress-induced ST depression had a reasonable positive predictive value (85 %). There was no association between TIMI grade and reversibility. In segments supplied by a TIMI 0 artery, a higher rate of fixed perfusion defects was associated with the absence of collateral circulation (75 % vs 22%; p < 0.013). Furthermore, severe impairment of contractility did not predict absence of viability, we identified as viable 55 % of akinetic segments and 29 % of segments classified angiographically as aneurysm.
Conclusions: These data suggest that common clinical and angiographic markers of severity of coronary artery disease are not useful in the detection of viable myocardium after myocardial infarction. Collateral circulation to occluded arteries was associated with viability, but its absence did not exclude it. Viability detection with appropriated tests, namely stress reinjection thalium scintigraphy should perhaps be considered as a routine procedure after myocardial infarction, especially when interventional therapy is to be considered.