Outcomes of predefined optimisation criteria for intravascular ultrasound guidance of left main stenting

Although intravascular ultrasound (IVUS) guidance has been useful in stenting for unprotected left main coronary artery stenosis, its impact on long-term mortality is still unclear. In the MAIN-COMPARE registry, patients with unprotected left main coronary artery stenosis in a hemodynamically stable condition underwent elective stenting under the guidance of IVUS (756 patients) or conventional angiography (219 patients). Patients with acute myocardial infarction were excluded. The 3-year outcomes between the 2 groups were primarily compared using propensity-score matching in the entire and separate populations according to stent type. In 201 matched pairs of the overall population, there was a tendency of lower risk of 3-year morality with IVUS guidance compared with angiography guidance (6.0% versus 13.6%, log-rank P=0.063; hazard ratio, 0.54; 95% CI, 0.28 to 1.03; Cox-model P=0.061). In particular, in 145 matched pairs of patients receiving drug-eluting stent, the 3-year incidence of mortality was lower with IVUS guidance as compared with angiography guidance (4.7% versus 16.0%, log-rank P=0.048; hazard ratio, 0.39; 95% CI, 0.15 to 1.02; Cox model P=0.055). In contrast, the use of IVUS guidance did not reduce the risk of mortality in 47 matched pairs of patients receiving bare-metal stent (8.6% versus 10.8%, log-rank P=0.35; hazard ratio, 0.59; 95% CI, 0.18 to 1.91; Cox model P=0.38). The risk of myocardial infarction or target vessel revascularization was not associated with the use of IVUS guidance. Elective stenting with IVUS guidance, especially in the placement of drug-eluting stent, may reduce the long-term mortality rate for unprotected left main coronary artery stenosis when compared with conventional angiography guidance.

Factors leading to subacute stent thrombosis after percutaneous coronary intervention (PCI) have not been well established. We assessed the pre- and post-PCI intravascular ultrasound (IVUS) characteristics of subacute stent thrombosis. We analyzed 7484 consecutive patients without acute myocardial infarction who were treated with PCI and stenting and underwent IVUS imaging during the intervention. Twenty-seven (0.4%) had angiographically documented subacute closure 1 of these abnormal morphologies also had reduced lumen dimensions post-PCI (final lumen <80% reference lumen). Preprocedural lesion characteristics were not different from matched lesions. Subacute stent thrombosis is infrequently related to the preintervention lesion characteristics. Inadequate postprocedure lumen dimensions, alone or in combination with other procedurally related abnormal lesion morphologies (dissection, thrombus, or tissue prolapse), contribute to this phenomenon.

We assessed the optimal intravascular ultrasound (IVUS) stent area to predict angiographic in-stent restenosis (ISR) after sirolimus-eluting stent implantation for unprotected left main coronary artery (LM) disease. A total of 403 patients treated with single- or 2-stent strategies (crushing and T-stent) had immediate poststenting IVUS and 9-month follow-up angiography. Poststenting minimal stent area (MSA) was measured in each of 4 segments: ostial left anterior descending (LAD), ostial left circumflex (LCX) polygon of confluence (POC, confluence zone of LAD and LCX), and proximal LM above the POC. Overall, 46 (11.4%) showed angiographic restenosis at 9 months: 3 of 67 (4.5%) nonbifurcation lesions treated with a single-stent, 14 of 222 (6.3%) bifurcation lesions treated with single-stent crossover, and 29 of 114 (25.4%) of bifurcation lesions treated with 2 stents. The MSA cutoffs that best predicted ISR on a segmental basis were 5.0 mm(2) (ostial LCX ISR), 6.3 mm(2) (ostial LAD ISR), 7.2 mm(2) (ISR within the POC), and 8.2 mm(2) (ISR within the LM above the POC). Using these criteria, 133 (33.8%) had underexpansion of at least 1 segment. Angiographic ISR (at any location) was more frequent in lesions with underexpansion of at least 1 segment versus lesions with no underexpansion (24.1% versus 5.4%, P<0.001). Two-year major adverse coronary event-free survival rate was significantly lower in patients with underexpansion of at least 1 segment versus lesions with no underexpansion (90±3% versus 98±1%, log-rank P<0.001), and poststenting underexpansion was an independent predictor for major adverse cardiac events (adjusted hazard ratio, 5.56; 95% confidence interval, 1.99-15.49; P=0.001). With these criteria, IVUS optimization during LMCA stenting procedures may improve clinical outcomes.