FUNCTIONAL ASSESSMENT OF PTCA RESULTS BY STRESS ECHOCARDIOGRAPHY - WHEN AND HOW TO TEST

Angiographic follow-up has shown that restenosis after PTCA is a conti nuous and ubiquitous process rather than a dichotomous event. Since th e functional significance of restenosis involves more factors than min imal lumen diameter functional tests after PTCA cannot be expected to match exactly the degree of angiographic restenosis. In the past, nucl ear perfusion imaging has been the most accurate non-invasive method t o predict restenosis, but now there is a new technique: stress echo. T his uses physical (treadmill, exercise), pharmacological (dipyridamole , dobutamine), or pacing stress (together with transoesophageal imagin g) for the detection of stress-inducible wall motion abnormalities; re solution of resting abnormalities may also be observed. These stress m odalities have been employed to detect restenosis in limited numbers o f patients, with diagnostic accuracies (so far, except for dobutamine) comparable to nuclear imaging Therefore, it seems that the decision t o use echo stress testing depends on patient characteristics, availabi lity of methods, and, importantly, experience of the echo laboratory. Timing of the test after PTCA must take into account delayed functiona l recovery after PTCA; this has been well described by nuclear perfusi on imaging. Thus, very early (<1 month) tests lack specificity On the other hand, development of restenosis after 6 months is rare. Stress t ests therefore should be performed within the time window of 1 to 6 mo nths after PTCA.