Predictors for functionally significant in-stent restenosis: an integrated analysis using coronary angiography, IVUS, and myocardial perfusion imaging.

Objective: The aim of this study was to assess the clinical and morphological predictors for functionally significant in-stent restenosis (ISR).

Background: Although they have been studied de novo in native coronary artery lesions, the relationships between clinical and morphological characteristics and the hemodynamic significance of ISR are not well understood.

Methods: In 175 patients with ISR of a single coronary artery (angiographic stenosis >50%), we compared quantitative coronary angiography and intravascular ultrasound (IVUS) with stress myocardial single-photon emission computed tomography (SPECT). A positive SPECT was a reversible perfusion defect in the territory of the ISR artery.

Results: Overall, 103 (59%) patients had a positive SPECT. In-segment IVUS minimal lumen area (MLA) was significantly smaller in lesions with positive SPECT compared with negative SPECT (1.7 ± 0.5 mm(2) vs. 2.4 ± 0.8 mm(2), p < 0.001). Stent underexpansion (minimal stent area <5.0 mm(2)) was more common in the positive SPECT group than in the negative SPECT group (52% vs. 32%, p = 0.010). A positive SPECT was seen in 54% (65 of 121) of focal ISR lesions compared with 70% (38 of 54) of multifocal or diffuse ISR lesions as assessed by IVUS (p = 0.039). Independent determinants for a positive SPECT were diabetes (odds ratio [OR]: 2.41; 95% confidence interval [CI]: 1.02 to 5.68; p = 0.046), in-segment angiographic diameter stenosis (OR: 1.06; 95% CI: 1.03 to 1.09; p < 0.001), in-segment IVUS-MLA (OR: 0.30; 95% CI: 0.14 to 0.63; p = 0.001), stent underexpansion (minimal stent area <5.0 mm(2)), (OR: 2.91; 95% CI: 1.19 to 7.07; p = 0.019), proximal location of the IVUS-MLA (OR: 4.62; 95% CI: 1.75 to 12.18; p = 0.002), and a multifocal or diffuse ISR pattern (OR: 2.50; 95% CI: 0.99 to 6.28; p = 0.050). An in-segment angiographic diameter stenosis ≥69.5% (72% sensitivity, 74% specificity, area under the curve = 0.793) and an IVUS-MLA ≤1.9 mm(2) (67% sensitivity, 75% specificity, area under the curve = 0.756) best predicted a positive SPECT; however, the overall diagnostic accuracies were only 73% and 70%, respectively.

Conclusions: In lesions with ISR, neither angiography nor IVUS accurately predicted an abnormal SPECT.