Fractional Flow Reserve and Clinical Outcome

Abstract

There is ample inferential evidence that patients with physiologically significant stenoses are at increased risk¹. Patients with proven coronary artery disease and in whom signs of myocardial ischemia are observed at low workload have an adverse event rate which is four times higher than in those with similar stenoses but in whom ischemia can only be provoked during exercise^2,3. This relationship between inducible ischemia and poor prognosis has led to the wide acceptance of treating functionally important stenoses even though their angiographic appearance is mild or moderate. The converse, not treating angiographically significant but functionally mild lesions, remains more controversial. The prevalence of angiographically significant lesions in an arbitrary population of 60-year-old asymptomatic males, is 20% and many of these lesions have probably no functional significance⁴. However, cardiologists are reluctant to leave untreated an angiographically significant stenosis, even when no objective signs of ischemia can be induced. This explains, at least in part, why a considerable number of angioplasties are performed without proof of reversible myocardial ischemia⁵. It is likely that a number of these angioplasties are based on an “oculo-stenotic” reflex and are possibly unnecessary.