Abstract 911: Usefulness of Coronary Fractional Flow Reserve Measurements to Guide Clinical Decisions in Intermediate Left Main Coronary Stenoses. Results of a Study Including 142 Consecutive Patients
Background: Limited data exist on the use of fractional flow reserve (FFR) measurements to guide clinical decisions in patients with intermediate left main coronary artery (LMCA) stenosis.
Objectives: To evaluate the usefulness of FFR measurements to guide the clinical decision in patients with intermediate LMCA stenosis and to determine the predictors of major adverse cardiac events [MACE] (cardiac death, myocardial infarction, coronary revascularization) in such cases. Methods: A total of 142 consecutive patients (mean age 62 ± 10 yrs) with intermediate LMCA stenosis (mean percent diameter stenosis 42 ± 13%) were included. All patients underwent FFR measurement after intracoronary (ic) administration of adenosine at a dose ≥30 μg. Special care was taken in cases with ostial lesions to pull the catheter out of the LMCA after adenosine administration. The clinical decisions were based on FFR as follows: coronary revascularization was recommended if FFR was <0.75, medical treatment if FFR was >0.80, and individualized decision based on additional clinical data if FFR was between 0.75 and 0.80. The occurrence of MACE was evaluated at 14 ± 11 months follow-up.
Results: Mean FFR was 0.81 ± 0.09 after the administration of a mean dose of 176 ± 99 μg of ic adenosine. Based on FFR results, sixty patients (42%) underwent coronary revascularization and 82 patients (58%) received medical treatment. At follow-up, the incidence of MACE related to the LMCA stenosis was 13% in the medical treatment group and 7% in the coronary revascularization group (p=0.27). The incidence of cardiac death and myocardial infarction was 7% in both groups (p=1.0). In the medical treatment group, patients with MACE had received a lower dose of ic adenosine (86 ± 57 μg vs. 167 ± 102 μg, OR: 1.39 for each decrease of 30 μg of ic adenosine, 95% CI 1.02–1.89, p=0.04) and were more frequently diabetics (55% vs. 21%, OR: 4.40, 95% CI 1.17–16.42, p=0.02).
Conclusions: FFR measurement is helpful in guiding the decision as to whether to revascularize patients with intermediate LMCA stenosis. However, diabetic patients remain at higher risk, and higher doses than previously recommended of ic adenosine should be used in the evaluation of LMCA to avoid cardiac events due to underestimation of stenosis severity.