Significance of spontaneous obstruction of high degree coronary artery stenoses between diagnostic angiography and later percutaneous transluminal coronary angioplasty

Among 265 patients with severe coronary artery stenoses amenable to percutaneous transluminal coronary angioplasty, 13 (5%) developed new total coronary occlusion of the vessel to be dilated during the period between diagnostic coronary angiography and repeat coronary angiography at the time of the operation. Time from diagnostic to “therapeutic” angiography (76 ± 74 vs 31 ± 31 days, p < 0.0001), degree of coronary stenosis on diagnostic angiography (85 ± 7 vs 80 ± 8%, p < 0.05) and impaired coronary flow distal to the narrowing (Thrombolysis in Myocardial Infarction grade 2: 38 vs 10%, p < 0.01) were the only variables related to the occurrence of spontaneous coronary occlusion. The clinical course of the patients who developed new total coronary occlusion was remarkably favorable. Twelve of the 13 patients had unchanged or improved anginal symptoms. The electrocardiogram at rest remained unchanged in 11 patients and there was no transmural myocardial infarction. Eight patients had 2 ventriculograms and the mean ejection fraction remained unchanged (only 2 patients had >5% decrease in ejection fraction between the 2 examinations). Spontaneous occlusion of high degree coronary artery stenoses is not unusual and is usually well tolerated, presumably due to the development of collateral circulation.