Rational and design of the European randomized Optical Coherence Tomography Optimized Bifurcation Event Reduction Trial (OCTOBER).

Background: Percutaneous coronary intervention in complex bifurcation lesions is prone to suboptimal implantation results and is associated with increased risk of subsequent clinical events. Angiographic ambiguity is high during bifurcation stenting, but it is unknown if procedural guidance by intravascular optical coherence tomography (OCT) improves clinical outcome. Methods and Design: OCTOBER is a randomized, investigator-initiated, multicenter trial aimed to show superiority of OCT-guided stent implantation compared to standard angiographic-guided implantation in bifurcation lesions. The primary outcome measure is a 2-year composite end point of cardiac death, target lesion myocardial infarction, and ischemia-driven target lesion revascularization. The calculated sample size is 1,200 patients in total, and allocation is 1:1. Eligible patients have stable or unstable angina pectoris or stabilized non­ST elevation myocardial infarction, and a coronary bifurcation lesion with significant main vessel stenosis and more than 50 % stenosis in a side branch with a reference diameter ≥2.5mm. Treatment is performed by the provisional side branch stenting technique or 2-stent techniques, and the systematic OCT guiding protocol is aimed to evaluate (1) plaque preparation, (2) lesion length, (3) segmental reference sizes, (4) lesion coverage, (5) stent expansion, (6) malapposition, (7) wire positions, and (8) ostial results. Implications: A positive outcome of the OCTOBER trial may establish OCT as a routine tool for optimization of complex percutaneous coronary intervention, whereas a negative result would indicate that OCT remains a tool for ad hoc evaluation in selected cases.

Unintended Deformation of Stents During Bifurcation PCI: An OCTOBER Trial Substudy.

BACKGROUND: Unintended deformation of implanted coronary stents can lead to loss of coronary access, stent thrombosis and coronary events during follow-up. The incidence, mechanisms and clinical outcomes of unintended stent deformations (USD) during complex bifurcation stenting are not well characterized. OBJECTIVES: In a prespecified analysis of the OCTOBER (European Trial on Optical Coherence Tomography Optimized Bifurcation Event Reduction) trial, we aimed to: 1) determine the incidence and characterize mechanisms of USD identified by optical coherence tomography (OCT); and 2) evaluate physician's detection and correction of accidental abluminal rewiring and USD. METHODS: OCT scans were analyzed for accidental abluminal rewiring and USD. When USD was identified, the plausible mechanism was determined by analysis of all procedural OCT scans and the corresponding angiograms. RESULTS: USD was identified by the core lab in 9.3% (55/589) of OCT-guided cases. Accidental abluminal rewiring was the cause in 44% (24/55), and guide catheter collision was the cause in 40% (22/55) of cases. USD was found in 18.5% of all cases with left main bifurcation percutaneous coronary intervention. The total incidence of abluminal rewiring was 33 in 32 OCT-guided cases (5.4%) and was corrected by physicians in 18 of 33 appearances (54.5%). The 2-year major adverse cardiac event rate for patients with untreated USD (n = 30) was 23.3%, whereas patients with confirmed or possibly corrected USD (n = 25) had no events during follow-up. CONCLUSIONS: USD was associated with adverse procedural complications and cardiac events during follow-up when not identified and corrected. The predominant mechanisms were undetected abluminal rewiring and guide catheter collision. Left main bifurcation percutaneous coronary intervention was a particular risk with USD detected in 18.5% of cases.

Comparison of definitions of coronary artery reference sizes and effects on stent selection and evaluation of stent expansion.

Accurate determination of coronary reference size is essential for optimal stent selection and evaluation of stent expansion during percutaneous coronary intervention (PCI). Several approaches for reference size estimation have been published with no universal agreement. The aim of this study was to investigate if potential differences in coronary reference size estimation lead to differences in stent and balloon selection and in detection of stent under expansion. Definitions for coronary reference size estimation, stent size selection, and stent expansion were identified in 17 randomized controlled trials. The identified methods were applied in a population of 32 clinical cases. Reference size estimates ranged up to 1.35mm, and indicated nominal stent size ranged up to 1.0 mm in the same case depending on method. Mean relative stent expansion ranged from 54±12% to mean 100±29% depending on the applied reference method. Choice of method for reference size estimation using intravascular imaging may influence stent selection and greatly affects evaluation of post-PCI stent expansion.

Everolimus-eluting bioresorbable scaffold versus everolimus-eluting metallic stent in primary percutaneous coronary intervention of ST-segment elevation myocardial infarction: a randomized controlled trial.

BACKGROUND: Primary percutaneous coronary intervention with implantation of a metallic drug-eluting stent (DES) is the standard treatment for patients presenting with ST-elevation myocardial infarction (STEMI). Implantation of a bioresorbable scaffold (BRS) during STEMI represents a novel strategy without intravascular metal. OBJECTIVE: The aim of the study was to investigate 12-month healing response in an STEMI population after implantation of either the Absorb BRS or Xience DES (Abbott Vascular, USA). METHODS: The present trial was a prospective, randomized, controlled, nonblinded, noninferiority study with planned inclusion of 120 patients with STEMI. Patients were randomly assigned 1:1 to treatment with Absorb BRS or Xience DES. Implantation result and healing response were evaluated by angiography and optical coherence tomography (OCT) at baseline and 12-month follow-up. The primary endpoint was minimum flow area (MFA) assessed at 12 months. Coronary stent healing index (CSHI) was calculated from OCT images. RESULTS: Out of 66 included patients, 58 had follow-up OCT after 12 months, and 49 entered matched analysis. One death occurred in each group; none were stent-related. MFA was 5.13 ± 1.70 mm2 (95% CI, 4.44-5.82) in the BRS group compared with 6.30 ± 2.49 mm2 (95% CI, 5.22-7.37) (P = 0.06) in the DES group. Noninferiority could not be evaluated. CSHI for both groups had a median score of 3. CONCLUSION: The DES group performed numerically better in primary and secondary endpoints, but the CSHI showed good stent healing in both groups.

Evaluation of Coronary Artery Stenosis by Quantitative Flow Ratio During Invasive Coronary Angiography: The WIFI II Study (Wire-Free Functional Imaging II).

BACKGROUND: Quantitative flow ratio (QFR) is a novel diagnostic modality for functional testing of coronary artery stenosis without the use of pressure wires and induction of hyperemia. QFR is based on computation of standard invasive coronary angiographic imaging. The purpose of WIFI II (Wire-Free Functional Imaging II) was to evaluate the feasibility and diagnostic performance of QFR in unselected consecutive patients. METHODS AND RESULTS: WIFI II was a predefined substudy to the Dan-NICAD study (Danish Study of Non-Invasive Diagnostic Testing in Coronary Artery Disease), referring 362 consecutive patients with suspected coronary artery disease on coronary computed tomographic angiography for diagnostic invasive coronary angiography. Fractional flow reserve (FFR) was measured in all segments with 30% to 90% diameter stenosis. Blinded observers calculated QFR (Medis Medical Imaging bv, The Netherlands) for comparison with FFR. FFR was measured in 292 lesions from 191 patients. Ten (5%) and 9 patients (5%) were excluded because of FFR and angiographic core laboratory criteria, respectively. QFR was successfully computed in 240 out of 255 lesions (94%) with a mean diameter stenosis of 50±12%. Mean difference between FFR and QFR was 0.01±0.08. QFR correctly classified 83% of the lesions using FFR with cutoff at 0.80 as reference standard. The area under the receiver operating characteristic curve was 0.86 (95% confidence interval, 0.81-0.91) with a sensitivity, specificity, negative predictive value, and positive predictive value of 77%, 86%, 75%, and 87%, respectively. A QFR-FFR hybrid approach based on the present results enables wire-free and adenosine-free procedures in 68% of cases. CONCLUSIONS: Functional lesion evaluation by QFR assessment showed good agreement and diagnostic accuracy compared with FFR. Studies comparing clinical outcome after QFR- and FFR-based diagnostic strategies are required. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02264717.