Radionuclide methods to evaluate percutaneous transluminal coronary angioplasty

Fatty acid exercise scintigraphy after percutaneous transluminal coronary angioplasty

We performed a sequential fatty acid exercise-rest scintigraphy in 18 patients with an initially successful percutaneous transluminal coronary angioplasty (PTCA) to study the concordance of trends in symptoms, exercise tolerance and myocardial metabolism. Eleven patients stopped the exercise because of angina pectoris in the preoperative test; 2 days after PTCA this number decreased to two, but again increased to eight 3 months later. Exercise time (9.7 +/- 0.6 min, mean +/- SEM) and maximum exercise heart rate (128 +/- 4 beats min-1) were at least as good immediately after the operation as originally (8.8 +/- 0.6 min and 121 +/- 4 beats min-1, respectively). After 3 months both parameters were significantly (P < 0.05) better (10.3 +/- 0.6 min and 136 +/- 4 beats min-1, respectively) than originally. Some relative improvement in washout was noticed in 61% 2 days and in 56% of cases 3 months after PTCA. Fatty acid exercise uptake was more homogeneous in 72% of cases immediately after angioplasty and in 44% 3 months later. The trend in fatty acid uptake, exercise characteristics, and also in symptoms was most favourable among the eight patients with a dilatated left anterior descending coronary artery. Although the gamma camera technique possibly underestimated the effects of angioplasty, the impaired fatty acid metabolism could be linked with persistent symptoms after the operation. We conclude that most patients can safely participate in a symptom-limited (maximal) ergometry test already 2 days after PTCA, and that postoperatively myocardial perfusion and metabolism improve rapidly. However, this advantage is eventually lost to some degree, even if exercise tolerance continues to improve.

The role of noninvasive cardiac imaging in the evaluation of the postcoronary intervention patient

Noninvasive diagnostic techniques are playing an increasingly prominent role in the evaluation of the postcoronary interventional patient. Radionuclide myocardial perfusion imaging has proved to be of value in assessing procedural success in patients with suboptimal angiographic results and/or multivessel coronary artery disease. However, in asymptomatic patients with single vessel disease, the use of myocardial perfusion imaging may not be cost-effective for follow-up after successful coronary intervention. The timing of these studies is important when used to predict coronary restenosis. Radionuclide ventriculography and echocardiography are two imaging modalities that, in conjunction with exercise stress, can be used to predict patient outcome and clinical events postcoronary intervention. A high degree of operator expertise is required for the optimal interpretation of the echocardiographic studies.