Area of myocardium at risk and lesion length are predictors of functionally significant coronary artery stenoses assessed by fractional flow reserve.

Background: Angiographic evaluation of diameter stenosis has only modest predictive value for functionally significant coronary-artery-stenoses as assessed by fractional-flow-reserve (FFR). Lesion length and assessment of area of myocardium at risk (BAR Imyocardial- jeopardy-index) subtended by the stenotic coronary arteries are also predictors of functionally significant coronary-artery-stenoses. We compared the diagnostic accuracy of minimal-lumen-diameter (MLD), lesion length and BARI-myocardial-jeopardy-index (MJI) in prediction of significantly reduced FFR (<=0.8). Method(s): We assessed consecutive patients who underwent coronary angiography and FFR. Lesion length and MLD were assessed by QCA. Estimation of area-of myocardium at risk subtended by coronary stenoses was performed using the BARI-MJI. Coronary stenoses were classified as functionally significant when FFR was <=0.8. Result(s): One hundred and ninety-six consecutive patients (age 65.6+/-10.9; 69% male, 306 vessels) were included. 117 vessels (51%) had FFR <=0.8. The BARI MJI was 34.2+/-13.8 in vessels with FFR <=0.8 compared to 21.8+/-11.0 in vessels with FFR >0.8 (P < 0.001). The mean lesion length in vessels with FFR <=0.8 was 18.7mm vs 9.37mm in vessels with FFR >0.8 (P < 0.001). The MLD in vessels with FFR <=0.8 was 1.16+/-0.458 mm compared to 1.51+/-0.470 mm in vessels with FFR >0.8 (P < 0.001). The bootstrapped Harrell's c-statistic of BARI MJI, lesion length and MLD in predicting significant FFR were 0.76 (0.71-0.82), 0.75 (0.70-0.80) and 70 (0.65-0.75), respectively. Conclusion(s): Diameter stenosis alone has modest predictive value of significant FFR. Area of myocardium at risk and lesion length are also predictors of functionally significant coronary artery stenoses.