Ischemia-guided myocardial revascularization: the oculo-ischemic reflex.

Abstract

In stable coronary artery disease, the indication for revascularization procedures based on the anatomical detection of stenotic coronary lesions, regardless of clinical findings, has been called 'oculostenotic reflex'. That expression was ironically created by Topol E. and Nissen S., and aimed at warning about the fact that not every obstruction has to be approached invasively1. At least from the academic viewpoint, that reflex seems to have been overcome, being currently considered an overtreatment2. However, the belief that the demonstration of myocardial ischemia by use of complementary methods indicates the need for revascularization still persists, and has been called 'oculo-ischemic reflex'. Let us consider an asymptomatic individual, undergoing routine myocardial scintigraphy, which detects ischemia in two coronary artery territories. Based on that result, the patient is submitted to coronary angiography, which identifies 75% stenoses in the middle third of the anterior descending coronary artery and in the proximal third of the right coronary artery. Although the patient is asymptomatic and has good ventricular function, the physician indicates pharmacological stent implantation in both lesions, based on the presence of myocardial ischemia identified in both vascular territories. The hypothesis that revascularization is beneficial in cases like that is grounded in the association between myocardial ischemia presence/extent and worse prognosis, which characterizes ischemia as a risk marker3,4. However, the idea that interfering with a risk marker necessarily ensures clinical benefit is an example of normalization heuristic5. That cognitive error occurs when a physician believes that the mere correction of parameters (ischemia) will necessarily imply a benefit to a patient. In that scenario, the indication of a coronary intervention requires the demonstration of its clinical benefit via studies evidencing interaction between the presence of ischemia and the efficacy of myocardial revascularization. The present study review the scientific evidence that tests the 'oculo-ischemic reflex' by use of interaction analysis in randomized clinical trials. Randomized clinical trials In stable coronary artery disease, randomized clinical trials have shown that myocardial revascularization does not usually prevent major cardiovascular events, such as death and myocardial infarction6-8. What those clinical trials have reported on patients with myocardial ischemia should be assessed. That is, would myocardial revascularization provide an additional benefit regarding the prevention of major cardiovascular events to patients with ischemia?