Background: The prognostic importance of significant left main coronary artery disease is unequivocal. However, moderate lesions of the left main coronary artery (LMCA) are sometimes found in patients presenting significant stenosis in other coronary arteries or equivocal symptoms. The ability of myocardial fractional flow reserve (FFR) to predict coronary events could be useful in the decision-making process in these patients. The present study was designed to investigate the occurrence of cardiac events in patients with coronary syndromes and LMCA stenosis of moderate severity in whom FFR failed to show an haemodynamic significant repercussion of the LMCA.
Methods and results: We studied 27 consecutive patients (mean age 62.7 +/- 10.5 years) with moderate stenoses (30-50%) of the LMCA. In seven patients who presented significantly reduced FFR (< 0.75) at the LMCA level (Group A), coronary revascularization of this vessel was performed. In 20 patients with negative FFR (greater than or equal to 0.75) at the LMCA level (Group B), the LMCA stenosis was not revascularized, being the revascularization procedures (if any) limited to other arteries with significant obstructions. During a mean follow-up period of 26.2 +/- 12.1 months, clinical events occurred in 3 patients in the whole group. One patient with positive FFR died during coronary bypass surgery. Two group B patients were surgically revascularized 4 months and 4 years after the initial coronariography.
Conclusions: Patients with coronary lesions of moderate severity on the LMCA and negative FFR may constitute a subgroup of good prognosis in the follow-up. Our findings suggest that negative FFR is a potentially useful indicator of the likelihood of cardiac events, and thus represents a useful aid in clinical decision-making in the hemodynamics laboratory.