Optical Coherence Tomography for Neurovascular Disorders

Diagnosis of cerebrovascular disease includes vascular neuroimaging techniques such as computed tomography (CT) angiography, magnetic resonance (MR) angiography (with or without use of contrast agents) and catheter digital subtraction angiography (DSA). These techniques provide mostly information about the vessel lumen. Vessel wall imaging with MR seeks to characterize cerebrovascular pathology, but with resolution that is often insufficient for small lesions. Intravascular imaging techniques such as ultrasound and optical coherence tomography (OCT), used for over a decade in the peripheral circulation, is not amendable to routine deployment in the intracranial circulation due to vessel caliber and tortuosity. However, advances in OCT technology including the probe profile, stiffness and unique distal rotation solution, holds the promise for eventual translation of OCT into the clinical arena. As such, it is apropos to review this technology and present the rationale for utilization of OCT in the cerebrovasculature.

Elastic stent recoil in coronary total occlusions: Comparison of durable-polymer zotarolimus eluting stent and ultrathin strut bioabsorbable-polymer sirolimus eluting stent

Objectives

To compare stent recoil (SR) of the thin‐strut durable‐polymer Zotarolimus‐eluting stent (dp‐ZES) and the ultrathin‐strut bioabsorbable‐polymer Sirolimus‐eluting stent (bp‐SES) in chronic total occlusions (CTOs) and to investigate the predictors of high SR in CTOs.

Background

Newer ultrathin drug eluting stent might be associated with lower radial force and higher elastic recoil due to the thinner strut design, possibly impacting on the rate of in‐stent restenosis and thrombosis.

Methods

Between January 2017 and November 2019, consecutive patients with CTOs undergoing percutaneous coronary intervention were evaluated. Only patients treated with dp‐ZES or bp‐SES were included and stratified accordingly. Quantitative coronary angiography analysis was used to assess absolute SR, relative SR, absolute focal SR, relative focal SR, high absolute, and high relative focal SR.

Results

A total of 128 lesions (67 treated with dp‐ZES and 61 with bp‐SES) in 123 patients were analyzed. Between bp‐SES and dp‐ZES no differences were found in absolute SR (p = .188), relative SR (p = .138), absolute focal SR (p = .069), and relative focal SR (p = .064). High absolute and high relative focal SR occurred more frequently in bp‐SES than in dp‐ZES (p = .004 and p = .015). Bp‐SES was a predictor of high absolute focal SR (Odds ratio [OR] 3.29, 95% confidence interval [CI] 1.50–7.22, p = .003]. High‐pressure postdilation and bp‐SES were predictors of high relative focal SR (OR 2.22, 95% CI 1.01–4.86, p = .047; OR 2.74, 95% CI 1.24–6.02, p = .012, respectively).

Conclusions

Both stents showed an overall low SR. However, ultra‐thin strut bp‐SES was a predictor of high absolute and high relative focal SR.

A serial optical frequency-domain imaging study of early and late vascular responses to bioresorbable-polymer sirolimus-eluting stents for the treatment of acute myocardial infarction and stable coronary artery disease patients: results of the MECHANISM-ULTIMASTER study

The purpose of this study was to assess early and late vascular healing in response to bioresorbable-polymer sirolimus-eluting stents (BP-SESs) for the treatment of patients with ST-elevation myocardial infarction (STEMI) and stable coronary artery disease (CAD). A total of 106 patients with STEMI and 101 patients with stable-CAD were enrolled. Optical frequency-domain images were acquired at baseline, at 1- or 3-month follow-up, and at 12-month follow-up. In the STEMI and CAD cohorts, the percentage of uncovered struts (%US) was significantly and remarkably decreased during early two points and at 12-month (the STEMI cohort: 1-month: 18.75 ± 0.78%, 3-month: 10.19 ± 0.77%, 12-month: 1.80 ± 0.72%; p < 0.001, the CAD cohort: 1-month: 9.44 ± 0.78%, 3-month: 7.78 ± 0.78%, 12-month: 1.07 ± 0.73%; p < 0.001 respectively). The average peri-strut low-intensity area (PLIA) score in the STEMI cohort was significantly decreased during follow-up period (1.90 ± 1.14, 1.18 ± 1.25, and 1.01 ± 0.72; p ≤ 0.001), whereas the one in the CAD cohort was not significantly changed (0.89 ± 1.24, 0.67 ± 1.07, and 0.64 ± 0.72; p = 0.59). In comparison with both groups, differences of %US and PLIA score at early two points were almost disappeared or close at 12 months. The strut-coverage and healing processes in the early phase after BP-SES implantation were significantly improved in both cohorts, especially markedly in STEMI patients. At 1 year, qualitatively and quantitatively consistent neointimal coverage was achieved in both pathogenetic groups.

Coronary physiology before and after chronic total occlusion treatment: what does it tell us?

Studies performed in the last two decades demonstrate that after successful percutaneous coronary intervention (PCI) of a chronically occluded coronary artery, the physiology of the chronic total occlusion (CTO) vessel and dependent microvasculature does not normalise immediately but improves significantly over time. Generally, there is an increase in fractional flow reserve (FFR) in the CTO artery, a decrease in collateral blood supply and an increase in FFR in the donor artery accompanied by an increase in blood flow and decrease in microvascular resistance in the myocardium supplied by the CTO vessel. Analogous to these physiological changes, positive remodelling of the distal CTO artery also occurs over time, and intravascular imaging can be helpful for analysing distal vessel parameters. Follow-up coronary angiography with physiological measurements after several weeks to months can be helpful and informative in a subset of patients in order to decide upon the necessity for treatment of residual coronary artery stenosis in the vessel distal to the CTO or in the contralateral donor artery, as well as in deciding whether stent optimisation is indicated. We suggest that such physiological guidance of CTO procedures avoids unnecessary overtreatment during the initial procedure, guides interventions at follow-up, and improves our understanding of what PCI in CTO means.

The Bioengineered Combo Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Coronary Stent in Patients with Chronic Total Occlusion Evaluated by Clinical Outcome and Optical Coherence Tomography Imaging Analysis

We sought to determine the effects of the use of a Bioengineered Combo Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Coronary Stent (Combo^® DTS) in patients with chronic total occlusion (CTO) by evaluating clinical outcomes and by performing an optical coherence tomography (OCT) analysis. We retrospectively analyzed data from 39 patients who had successfully undergone OCT-guided revascularization of a CTO being treated with a Combo^® DTS. Clinical assessment, angiography (with quantitative coronary angiography analysis) and OCT examination were performed at baseline and at follow-up. The median follow-up period was 189 days, ranging from 157 to 615 days. At follow-up, revascularization was required due to angiographic restenosis in 40% (14 of 35) of patients. OCT analysis detected neointima proliferation in 23 (76.6%) patients. Neointima formation was often associated with microvessels in 18 patients (60%). Neoatheroslcerosis was observed in 2 (6.6%) patients. Malapposition was found in 4 patients (13.3%), and stent fractures were found in 11 patients (36.6%). Rate of strut coverage was 96.3% at follow-up. In conclusion, the implantation of a Combo^® DTS after successful CTO recanalization was associated with a restenosis rate of 40% despite good stent implantation at baseline, proven by OCT. Neointima formation was found as a main contributor to restenosis. Nevertheless, we observed a low rate of major cardiovascular events in our follow-up.

Intravascular Healing Is Not Affected by Approaches in Contemporary CTO PCI: The CONSISTENT CTO Study

OBJECTIVES

The aim of this study was to assess angiographic, imaging, and clinical outcomes following chronic total occlusion (CTO) percutaneous coronary intervention (PCI) with dissection and re-entry techniques (DART) and subintimal (SI) stenting compared with intimal techniques.

BACKGROUND

Reliable procedural success and safety in CTO PCI require the use of DART to treat the most complex patients. Potential concerns regarding the durability of DART with SI stenting still need to be addressed.

METHODS

This was a prospective, multicenter, single-arm trial of patients with appropriate indications for CTO PCI.

RESULTS

Successful CTO PCI was performed in 210 of 231 patients (91% success). At 1 year, the primary endpoint of target vessel failure (cardiac death, myocardial infarction related to the target vessel, or any ischemia-driven revascularization) occurred in 5.7% of patients, meeting the pre-set performance goal. Major adverse cardiovascular events (all-cause mortality, myocardial infarction, or target vessel revascularization) occurred in 10% at 1 year and 17% by 2 years and was not influenced by DART. Quality-of-life measures significantly improved from baseline to 12 months. There was no difference in intravascular healing assessed using optical coherence tomography at 12 months for patients treated with DART and SI stenting compared with intimal strategies.

CONCLUSIONS

Contemporary CTO PCI is associated with medium-term clinical outcomes comparable with those achieved in other complex PCI cohorts and significant improvements in quality of life. The use of DART with SI stenting does not adversely affect intravascular healing at 12 months or medium-term major adverse cardiovascular events. (Consistent CTO Trial; NCT02227771).

The Orsiro Ultrathin, Bioresorbable-Polymer Sirolimus-Eluting Stent: A Review of Current Evidence

Advances in stent design and the development of bioresorbable polymers have allowed the development of novel stent technologies such as the Orsiro bioresorbable-polymer sirolimus eluting stent (BP-SES). Over several noninferiority trials, the BP-SES has demonstrated itself to be a safe and effective therapy for obstructive coronary artery disease. This article reviews the current evidence of the efficacy of the BP-SES and examines its performance in high-risk populations, such as patients presenting with ST-segment myocardial infarction, chronic total occlusions, diabetes, and small vessel disease.

Subintimal Versus Intraplaque Recanalization of Coronary Chronic Total Occlusions: Mid-Term Angiographic and OCT Findings From the ISAR-OCT-CTO Registry

OBJECTIVES

The aim of this study was to compare angiographic and optical coherence tomography findings following subintimal as opposed to intraplaque recanalization of chronic total occlusions (CTOs).

BACKGROUND

There is ongoing controversy regarding outcomes of intraplaque versus subintimal CTO recanalization.

METHODS

Consecutive patients undergoing angiography and intravascular optical coherence tomography following CTO recanalization were included in the ISAR-OCT-CTO (Intracoronary Stenting and Angiographic Results - Optical Coherence Tomography for Chronic Total Occlusions) registry. The study endpoints were percent diameter stenosis and late lumen loss as well as rate of uncovered and malapposed struts. Independent correlates of uncovered and malapposed struts were assessed by multivariate analysis.

RESULTS

The study included 75 patients. Intraplaque and dissection and re-entry techniques (DART) were used in 46 and 29 patients, respectively. There were no differences in terms of in-segment percent diameter stenosis (median 36.9 [interquartile range (IQR): 26.4 to 43.1] vs. 31.2 [IQR: 23.2 to 49.5]; p = 0.656), in-stent late lumen loss (0.215 mm [IQR: 0.063 to 0.495 mm] vs. 0.230 mm [IQR: 0.060 to 0.645 mm]; p = 0.837), or in-segment late lumen loss (0.030 mm [IQR: -0.278 to 0.510 mm] vs. 0.130 mm [IQR: -0.120 to 0.500 mm]; p = 0.395) at follow-up between the 2 techniques. Optical coherence tomography analysis showed comparable strut coverage (79.9% vs. 71.3%; p = 0.255) but significantly higher strut malapposition (6.6% vs. 13.6%; p < 0.001) following DART. Use of DART independently correlated with presence of strut malapposition (odds ratio: 3.41; 95% confidence interval: 1.24 to 9.36; p = 0.017) but not of strut coverage (odds ratio: 0.65; 95% confidence interval: 0.28 to 1.49; p = 0.314).

CONCLUSIONS

Intraplaque and subintimal recanalization techniques are associated with comparable mid-term angiographic results. Although the rate of uncovered struts is high following CTO recanalization, the recanalization technique does not independently correlate with presence of uncovered struts. There is a high rate of strut malapposition following CTO recanalization, particularly if achieved by means of DART.

Two-year safety evaluation of a biodegradable polymer sirolimus-eluting stent with increased drug elution and polymer absorption kinetics in complex patient and lesion cohort

OBJECTIVES

The aim of the present report was to compare 2-year safety outcomes of two biodegradable polymer (BP) sirolimus-eluting stents (SESs) with different drug eluting and polymer absorption kinetics in a subgroup of complex patients and lesions.

BACKGROUND

The previously published PANDA III study showed the BuMA BP SES, with faster drug elution and polymer absorption, was non-inferior to the Excel SES in target lesion failure (TLF).

METHODS

In PANDA III trial, patients who fulfilled one or more of the following criteria were included: Small vessel disease (reference vessel diameter ≤ 2.5 mm); long lesion (lesion length ≥ 20 mm); chronic total occlusion lesion; and diabetic patients.

RESULTS

Among 2,348 patients randomly assigned to treatment with BuMA (n = 1,174) or Excel SES (n = 1,174) in the PANDA III study, 858 in the BuMA group and 855 in the Excel group satisfied the inclusion criteria. At 2-year follow-up, the incidence of definite/probable stent thrombosis (ST) was significantly lower with BuMA SES as compared with Excel SES (0.7% vs. 1.9%, p = 0.03). This difference was mainly caused by decreased subacute stent thrombosis rate (0% vs. 0.6%, p = 0.03). In patients who did not fulfill the complex patient and lesion criteria, there were no between-group difference in ST (0.7% vs. 0%, p = 0.50). Myocardial infarction and TLF rates were similar (5.7% vs. 6.0%, p = 0.79 and 8.8% vs. 7.5%, p = 0.34, respectively), whereas patient-oriented composite endpoint was higher with BuMA SES mainly due to high risk of revascularization (15.6% vs. 11.4%, p = 0.01; 8.4% vs. 4.6%, p < 0.01).

CONCLUSIONS

Two-year subgroup analysis of the all-comer PANDA III trial revealed the increased safety benefit of the BuMA SES is more prominently seen in complex patient and lesion population.

CLINICAL TRIAL

ClinicalTrial.gov, Identifier-NCT02017275.