Validation of intravascular ultrasound-derived parameters with fractional flow reserve for assessment of coronary stenosis severity.
BACKGROUND
We assessed optimal intravascular ultrasound (IVUS) criteria for predicting functional significance of intermediate coronary lesions.


RESULTS
Overall, 201 patients with 236 coronary lesions underwent IVUS and invasive physiological assessment before intervention. Fractional flow reserve (FFR) was measured at maximal hyperemia induced by intravenous adenosine infusion. FFR <0.80 at maximum hyperemia was seen in 49 (21%) of the overall 236 lesions. The independent determinants of FFR were minimal lumen area (MLA; β=0.020; 95% confidence interval [CI], 0.008 to 0.031; P=0.032), plaque burden (β=-0.002; 95% CI, -0.003 to 0.001; P=0.001), lesion length with a lumen area <3.0 mm(2) (β=-0.003; 95% CI, -0.005 to -0.001; P=0.005), and left anterior descending artery location (β=-0.035; 95% CI, -0.055 to -0.016; P=0.001). The best cutoff value (with a maximal accuracy) of the MLA to predict FFR <0.80 was <2.4 mm(2), with a diagnostic accuracy of 68% (90% sensitivity, 60% specificity, and area under the curve=0.800; 95% CI, 0.742 to 0.848; P<0.001). The cutoff value of plaque burden to predict FFR <0.80 was ≥79% (69% sensitivity, 72% specificity, and area under the curve=0.756; 95% CI, 0.696 to 0.810; P<0.001). The cutoff value of lesion length with a lumen area <3.0 mm(2) was 3.1 mm (84%sensitivity, 63%specificity, and area under the curve=0.765; 95% CI, 0.706 to 0.818; P<0.001). Among 117 lesions with an MLA ≥2.4 mm(2), 112 (96%) had an FFR ≥0.80,; and all but 1 showed FFR ≥0.75. Conversely, 44 (37%) lesions with an MLA <2.4 mm(2) had an FFR <0.80.


CONCLUSIONS
IVUS-derived MLA ≥2.4 mm(2) may be useful to exclude FFR <0.80, but poor specificity limits its value for physiological assessment of lesions with MLA <2.4 mm(2). Thus, FFR or stress tests may be necessary to accurately identify ischemia-inducible intermediate stenoses.
Department of Cardiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
Soo-Jin
SJ
Kang
Jong-Young
JY
Lee
Jung-Min
JM
Ahn
Gary S
GS
Mintz
Won-Jang
WJ
Kim
Duk-Woo
DW
Park
Sung-Cheol
SC
Yun
Seung-Whan
SW
Lee
Young-Hak
YH
Kim
Cheol Whan
CW
Lee
Seong-Wook
SW
Park
Seung-Jung
SJ
Park
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D018084:Ultrasonography, Interventional