PTCA-success: reliability of non-invasive methods

Summary

The main indication for PTCA is based on clinical symptoms. Therefore relief or improvement of angina and reduction of antianginal therapy are most important, although, subjective criteria of successful PTCA (short term and long term). As restenosis occurs in 20 to 33% (mostly within the first weeks) there is a need for an objective non-invasive indicator.

A new positive stress test is highly specific but a negative test does not exclude recurrence, as its sensitivity is only 50 to 70% and depends on the degree and location of stenosis. An increase of sensitivity can be reached by a withdrawal of antianginal therapy, if tolerated. The knowledge of a pathological stress test before PTCA makes it much easier to judge new symptoms. Therefore it is generally accepted to do a stress test in all patients before and after PTCA and to compare both with the angiographical results. Scintigraphical methods have been reported to be more sensitive. Regional perfusion disturbances assessed by thallium-201 exercise scintigraphy and no increase of left ventricular ejection fraction during exercise, measured by a gated blood pool technique with technetium-99m, indicate restenosis. Both are not available in most hospitals and expensive.

As the insufflation of the balloon produces complete coronary artery occlusion and regional well defined ischemia, we developed a mapping system with 63 x-ray transparent electrodes to detect the precordial region of ischemia according to the occluded vessel. These data provide important information of precordial regions with ischemic ECG changes and hopefully improve the sensitivity of ECG exercise tests. In conclusion, the use of clinical symptoms in conjunction with ECG and myocardial scintigram acquired during exercise provide a lot of information but can not substitute angiogram, if there is any suspicion of restenosis.