Abstract 912: Comparison of Coronary Fractional Flow Reserve and Intravascular Ultrasound Measurements for the Evaluation of Intermediate or Equivocal Left Main Coronary Artery Stenosis
Background: Limited data are available regarding the use of fractional flow reserve (FFR) and intravascular ultrasound (IVUS) measurements to determine the severity of intermediate left main coronary artery (LMCA) lesions.
to compare FFR and IVUS for the evaluation of intermediate or equivocal LMCA stenosis and
to determine the value of IVUS in a clinical decision-making process based on FFR.
Methods: Prospective study including 58 consecutive patients (age 60±10 years) with intermediate or equivocal LMCA stenosis (diameter stenosis:38±12%) that was evaluated with both FFR and IVUS. The LMCA stenosis was considered significant by FFR if it was <0.75 and by IVUS if minimal lumen area (MLA) was <6 mm2. Clinical decisions were based on FFR as follows: coronary revascularization (CR) if FFR was <0.75, medical treatment (MT) if FFR was >0.80, and individualized decision based on additional clinical data if FFR was between 0.75 and 0.80. Major adverse cardiac events [MACE] (cardiac death, myocardial infarction, CR) were evaluated at 11 ± 7 months follow-up.
Results: FFR and IVUS measurements differed regarding the severity of the LMCA stenosis in 22 patients (38%), with a lesion found significant by FFR and non-significant by IVUS in 4 patients (7%) and a lesion found non-significant by FFR and significant by IVUS in 18 patients (31%). Based on FFR measurements 21 patients underwent CR and 37 patients received MT. At follow-up, the incidence of MACE was 5% in the CR group and 16% in the MT group (p=0.40). In the MT group, patients with MACE had a significantly smaller MLA compared to those without MACE (4.84 ± 1.26 mm2 vs. 7.39 ± 3.56 mm2, p=0.005), and IVUS showed a significant stenosis in 83% of patients with MACE compared to 26% of patients without MACE (p=0.01).
Conclusions: FFR and IVUS measurements of intermediate LMCA lesions differed regarding the severity of stenosis in more than one third of patients. A clinical decision-making process based on FFR measurements seems to be appropriate in most cases, but IVUS measurements might further help to identify those patients at high-risk for cardiac events at follow-up. This suggests that the 2 techniques are complementary in the evaluation of intermediate LMCA stenosis.