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Background Identifying the individual hemodynamic significance of tandem coronary artery lesions can be complicated by the crosstalk phenomenon which occurs between serial stenoses under hyperemic conditions. Physiological assessments performed under resting conditions are considered to be, theoretically, less affected by the hemodynamic interaction between serial coronary stenoses. The purpose of this study was to assess whether pressure-wire (PW) pullback measurements at rest and during hyperemia provided different information as to which stenosis appeared to be most functionally significant. Methods In consecutive patients with angiographically discrete serial lesions, physiological lesion predominance (i.e. proximal or distal) was defined according to the pressure gradient along the vessels on PW-pullback trace. We used instantaneous wave-free ratio (iFR) based assessment as the reference standard and compared fractional flow reserve (FFR) based and hyperemic-iFR based lesion predominance. Results Eighty-eight vessels (70 patients, mean age 70.3 ± 9.4 years, 80% male) were included in this study. Median iFR, FFR and hyperemic-iFR were 0.85 (interquartile range [IQR]: 0.74 to 0.91), 0.73 (IQR: 0.65 to 0.80) and 0.60 (IQR: 0.49 to 0.71), respectively. When judged against iFR-pullback based physiological assessment, lesion predominance changed in 22.7% (20/88) in FFR and in 20.5% (18/88) in hyperemic-iFR, respectively. There was no statistical difference between FFR and hyperemic-iFR for the impact on these changes (p = 0.77). Conclusions In serial coronary lesions, hyperemic PW-pullback disagreed with resting PW-pullback on the lesion-specific identification of ischemia in approximately 20% of cases, either in whole cardiac cycle or in wave-free period.

Optical coherence tomography (OCT) has contributed to a better understanding of in-stent restenosis (ISR); however, studies evaluating ISR pattern after two-stent technique in unprotected left main (ULM) are lacking. We aim to evaluate the ISR pattern of proximal LAD and LCX after two-stent technique in ULM.We performed OCT in 26 patients with isolated or combined ISR (identified by angiography as50%) after two stent implantation in the proximal LCX and LAD. Finally, 13 LAD and 22 LCX ISR lesions underwent OCT assessments. OCT analyses were undertaken in the proximal segments of the LAD and LCX. In addition, we compared OCT findings in the flow divider (FD) and lateral wall (LW).In both the LAD and LCX, the distance from the ostium to the minimum lumen area (MLA; LAD, 2.00mm [1.00, 3.00]; LCX, 1.00mm [0.00, 1.80] distal to ostium) was short. Uncovered struts were more common on the FD side compared with the LW in the LAD (6.25% [0.00, 20.00] vs 0.00% [0.00, 0.00], respectively, p=0.016) and LCX (11.32% [0.00, 19.44] vs 0.00% [0.00, 4.55], respectively, p0.001). Conversely, neointimal hyperplasia (NIH) was significantly thicker on the FD side compared with the LW in the LCX (0.31mm [0.19, 0.47] vs 0.15mm [0.09, 0.31], p0.001).While uncovered struts were more commonly found on the FD side of both arteries, NIH was significantly thicker on the FD side compared with the LW in the LCX. These unique findings might indicate inferior outcomes after two-stent techniques in ULM bifurcation lesions.

Kissing-balloon technique (KBT) is commonly performed during percutaneous coronary intervention of distal unprotected left main coronary artery (ULM) aiming at obtaining optimal opening of the side branch (left circumflex artery; LCX) ostium. Nonetheless, detailed evaluation of vascular response to stents in LCX ostium is lacking. We therefore evaluated the vascular response to different drug-eluting stents (DES) in ostial LCX after ULM by means of optical coherence tomography (OCT).We prospectively enrolled 38 consecutive patients with ULM disease, who were treated with single-stent procedure using DES, crossover the ULM-left anterior descending artery (LAD) followed by KBT. Twelve patients were treated with sirolimus-eluting stents (SES) and 26 patients were treated with everolimus-eluting stents (EES). OCT was conducted at post-PCI and 9-month follow-up. We evaluated the DES-vessel interactions and number of stent struts at the side branch (LCX) ostium (SO) at post-PCI, and compared the narrowing of ostial area at LCX between SES and EES.Post-procedure, the number of stent struts at SO was significantly higher in SES compared to EES (median 14.47% vs 0.19%, p0.001). The narrowing of LCX ostial area at follow-up was more pronounced in SES compared with EES (29.16% vs 2.46%, respectively, p0.001). Linear regression analysis showed a high correlation between the number of stent struts in LCX ostium and ostial area narrowing (r=0.771, p0.001).OCT showed differences between EES- and SES-vessel interactions at ULM bifurcation PCI. Number of LCX ostium struts at post-PCI impacted the narrowing of ostial area at 9-month follow-up.