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Medical treatment was as effective as surgery for patients with moderate to severe isolated stenosis in the proximal left anterior descending artery who had fractional flow reserve (FFR) of 0.80 or greater, according to results from a single-center study.

Kaplan-Meier survival estimates at five years were 92.9% for those medically treated and 87.4% for those who underwent revascularization, according to the study published online in the Journal of the American College of Cardiology: Cardiovascular Interventions.

Patients in the revascularization group (coronary artery bypass graft or percutaneous coronary intervention) had fractional flow reserves of less than 0.80.

Compared with age- and gender-matched controls, medically treated patients had no increased risk of dying (HR: 1.03, 95% CI 0.68 to 1.57, P=0.87), Bernard De Bruyne, MD, PhD, from the Cardiovascular Center at OLV Clinic in Aalst, Belgium, and colleagues found.

"Left main stenosis has been an exclusion from many trials because of the common wisdom that all these patients should have surgery or percutaneous coronary intervention [PCI]," said Spencer B. King, MD, editor-in-chief of JACC: Interventions and past president of the American College of Cardiology, in a statement. "This study challenges that assumption and shows that left main stenosis does not automatically need intervention and those without hemodynamic impairment may have good survival without intervention."

Most of the 730 patients in this study had stable angina and all lesions were assessed visually or with quantitative coronary angiography (QCA) and fell between 30% and 70% stenosis.

All patients underwent fractional flow reserve testing, which measures pressure differences to determine whether a lesion has hemodynamic significance.

The mean diameter stenosis was significantly less in the medical group compared with the revascularization group whether assessed visually or with QCA.

The mean fractional flow reserve value was 0.87 for the medical group and 0.71 for the revascularization group.

The five-year survival estimates between the medical group and the matched controls (who were part of the Rotterdam Study, an ongoing prospective cohort study) were not statistically different (92.9% versus 89.6%, P=0.74).

De Bruyne and colleagues noted that the 30 deaths from all-cause mortality in the medical group corresponded to an annual death rate of 1.63%, which "is similar to the 1.5% annual death rate recently reported in individuals without known coronary artery disease but with multiple risk factors" (Eur J Epidemiol 2011; 26: 657–686).

"This study indicates that patients with an angiographically dubious, but hemodynamically nonsignificant, isolated stenosis in the proximal LAD (as assessed in the catheterization laboratory by FFR measurements) have a favorable long-term outcome without mechanical revascularization," the authors concluded.

The results confirm and extend data from other studies including the DEFER trial and the FAME trial, they said.

Upon findings of ischemia with stress testing, European clinical practice guidelines recommend revascularization.

But analyses of both private and Medicare insurance claims have shown that "more than 50% of patients with stable coronary artery disease lack an objective definition of ischemia by noninvasive testing before PCI," De Bruyne and colleagues wrote.

This "disconnect between recommendation and clinical practice," however, is not out of disregard for the guidelines. Many factors, such as obesity, age, and decreased left ventricular function, negate the usefulness of noninvasive stress testing.

Use of fractional flow reserve "makes it possible to obtain both anatomic and functional data during the same catheterization session," researchers said.

Limitations of the study include those inherent to an observational study. In addition, 94% of patients had stable coronary artery disease, which limits the generalizability of the results to other populations.

The authors also noted the large number of patients with stenoses less than 50% in whom revascularization is typically not considered. However, the angiogram "often underestimates the true severity of the stenosis" in the left main coronary artery.

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