Whatever you do: Do it cautiously and consider the consequences!

Abstract

Non-invasive cardiac imaging is widely used as gatekeeper for coronary angiography and revascularization in stable coronary artery disease (CAD)/chronic coronary syndrome. There are plenty of data demonstrating that referral rates to coronary angiography are higher in patients with than in patients without perfusion abnormalities, as assessed by myocardial perfusion SPECT (MPS) and positron emission tomography (PET). Moreover, observational studies reveal that stable CAD patients who undergo direct coronary angiography generate higher diagnostic costs and greater rates of intervention and follow-up costs than patients who first undergo MPS. Of note, the prognosis was not different in the before-mentioned patient groups. In the seminal propensity-matched retrospective patient cohort study by Hachamovitch et al, revascularization compared with medical therapy provided greater survival benefit in patients with moderate to large amounts of ischemia (myocardial ischemia[10% of the total myocardium). However, the prospective large randomized trials COURAGE, BARI-2D, and ISCHEMIA did not demonstrate a survival benefit of revascularization over medical therapy in stable CAD patients during relatively short follow-up periods. An important point is that a high number of patients randomized to medical therapy in these trials underwent revascularization during the follow-up period and thus were cross-over patients (21%, 32%, and 42% in ISCHEMIA, COURAGE, and BARI-2D, respectively). Unfortunately, no ‘‘on treatment analysis’’ of these studies is available so far. However, in the ISCHEMIA trial, patients assigned to the invasive strategy had better improvement in anginarelated health status than those assigned to the conservative strategy. Results of a meta-analysis of these three and other similar studies demonstrate a significant reduction of cardiac mortality in favor of coronary revascularization compared with medical therapy alone in stable CAD patients. The survival benefit was directly linked to the duration of the follow-up period and a lower risk of spontaneous myocardial infarction. Thus, what moves doctors and patients into the direction of invasive evaluation, coronary angiography, and revascularization in stable CAD?