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SUMMARY Forty-nine patients in whom percutaneous transluminal coronary angioplasty (PTCA) was attempted were evaluated by thallium-201 myocardial scintigraphy after exercise and at rest before the intervention. After successful PTCA of a single stenosis in a native vessel (30 of 44 patients) and of a stenosis in an aortocoronary bypass graft (three of five patients), scintigraphy was repeated within 3 weeks in 30 patients. Long-term follow-up studies by scintigraphy at 5-6-month intervals up to more than 2 years (mean follow-up 18 months) were performed in 16 patients.Before PTCA, clear-cut regions of decreased thallium-201 activity were observed in 43 of 49 patients. Thallium-201 activity within this zone was reduced to 74 ± 1% (SEM) of maximal myocardial thallium-201 activity after exercise, but returned to normal (> 80%) at rest (88 ± 1%, p < 0.001). After PTCA, no distinct defects were recognizable in the region of previously decreased thallium-201 activity, and the respective values were 89 ± 1% after exercise at identical work loads (p < 0.001 compared with the corresponding values before PTCA) and 94 + 1% (p < 0.01) at rest. These results paralleled the angiographic findings, which showed an increase in luminal diameter in the stenotic segment of the treated vessel from an average of 15 ± 2% of the pre-and poststenotic vessel diameter before PTCA to 67 ± 3% (p < 0.001) after PTCA. During long-term follow-up, thallium-201 activity remained normal after exercise in the entire heart in 13 of 16 patients. In three patients, a new defect in the same location as before treatment reappeared 4½/2, 6 and 29½/2 months after PTCA because the stenosis recurred, as documented by angiography.We conclude that thallium-201 exercise scintigraphy permits the best documentation of the ongoing changes in myocardial perfusion after PTCA.THE FEASIBILITY of instrumental exploration of the coronary arterial tree through a transaortic approach and its implications for removal of atheromatous tissue by retrograde curettage was first studied in dogs and human cadavers by May' and Absolon et al.2 Eight years later, Dotter and Judkins3 described a new nonoperative technique to dilate arteriosclerotic obstructions of the femoral arteries by means of tapered catheters of different outer diameters. In 1976, Gruentzig4' 5 reported encouraging results in the treatment of femoropopliteal and iliac artery obstructions using a double-lumen catheter with a nonelastic balloon at its tip. Once placed in the stenotic lesion, high pressure inflation of the balloon compressed the obstructing atheromatous material against the vascular wall, thereby enlarging the lumen. With miniaturization of the dilating catheter and with the development of appropriate guiding catheters adapted from the Judkins-type catheters for selective coronary arteriography, the system became suitable for the treatment of coronary artery stenoses.8

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SUMMARY To assess the usefulness of thallium-201 exercise scintigraphy in evaluating myocardial perfusion after coronary artery bypass surgery imaging was performed after submaximal bicycle ergometry and at rest in 54 patients before and within 24±10 (SD) weeks after operation. According to the postoperative scintigram the patients were assigned to three groups. Group 1 comprised 31 patients whose perfusion returned to normal after exercise and at rest within the preoperatively ischaemic regions; group 2 comprised 16 patients with identical pre-and postoperative exercise-induced perfusion defects, and group 3 comprised seven patients with enlarged or new perfusion defects postoperatively.Clinically, 14 of 31 patients in group 1 were symptom free after operation, two of whom, however, showed an abnormal exercise electrocardiogram; whereas the other 17 patients still complained of chest pain and in six of them the exercise electrocardiogram was also pathological. In group 2 eight of 16 patients were symptom free after operation and showed normal exercise electrocardiograms and the other eight continued to suffer from angina, and seven had a pathological exercise electrocardiogram. All seven patients in group 3 were symptomatic and showed an abnormal exercise electrocardiogram. Thus, scintigraphy identified eight of 20 patients (40%) who were symptom free and showed normal exercise electrocardiograms as still having exercise-induced ischaemia and thus as having not truly benefited from the surgical intervention. In contrast, improvement in perfusion was documented in 17 of 31 patients (53%) despite further complaints of chest pain and persistence of a pathological exercise electrocardiogram in six of them.Bypass graft patency rate paralleled the scintigraphic findings in the 35 patients who were restudied arteriographically. In group 1 (16 patients restudied) the graft patency rate was 81 per cent, significantly different from the 38 per cent in group 2 (13 patients restudied), and it was only 15 per cent in group 3 (six patients restudied). Similarly, the degree of vascular obstruction had decreased in group 1 from a score of 2 1 ±0 3 (SEM) preoperatively to a score of 1 1 ±0O3 postoperatively, remained unchanged in group 2, averaging 3± 0±04 score values preoperatively and 3-1±0-5 score values postoperatively, and even tended to increase in group 3 from 2-2 ±06 score values preoperatively to 3-3± 0-6 score values postoperatively.It is concluded that thallium-201 exercise scintigraphy is a useful technique to document changes in regional perfusion after surgery and is definitely superior to the clinical evaluation of patients including the exercise electrocardiogram.More than 10 years have elapsed since coronary management of coronary heart disease as a new artery bypass surgery was introduced into the therapeutic principle.

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