Fractional flow reserve measurements and long-term mortality-results from the FLORIDA study

Background

Randomized evidence suggested improved outcomes in fractional flow reserve (FFR) guidance of coronary revascularization compared to medical therapy in well-defined patient cohorts. However, the impact of FFR-guided revascularization on long-term outcomes of unselected patients with chronic or acute coronary syndromes (ACS) is unknown.

Aims

The FLORIDA (Fractional FLOw Reserve In cardiovascular DiseAses) study sought to investigate outcomes of FFR-guided vs. angiography-guided treatment strategies in a large, real-world cohort.

Methods

This study included patients enrolled into the German InGef Research Database. Patients undergoing coronary angiography between January 2014 and December 2015 were included in the analysis. Eligible patients had at least one inpatient coronary angiogram for suspected coronary artery disease between January 2014 and December 2015. Patients were stratified into FFR arm if a coronary angiography with adjunctive FFR measurement was performed, otherwise into the angiography-only arm. Matching was applied to ensure a balanced distribution of baseline characteristics in the study cohort. Patients were followed for 3 years after index date and primary endpoint was all-cause mortality.

Results

In the matched population, mortality at 3 years was 9.6% in the FFR-assessed group and 12.6% in the angiography-only group (p = 0.002), corresponding to a 24% relative risk reduction with use of FFR. This effect was most pronounced in patients in whom revascularization was deferred based on FFR (8.7% vs. 12.3%, p = 0.04) and in high-risk subgroups including patients aged ≥75 years (14.9% vs. 20.1%, p < 0.01) and those presenting with ACS (10.2% vs. 14.0%, p = 0.04).

Conclusions

FFR-based revascularization strategy was associated with reduced mortality at 3 years. These findings further support the use of FFR in everyday clinical practice.

Variability in research culture across busy catheterisation labs in the Asia-Pacific region

Background

Information related to research culture in the busy catheterisation (cath) labs across the Asia-Pacific (APAC) region is sparse.

Aims

The aims of this study were to examine the variability in research culture in busy cath labs in the APAC region and to propose a roadmap for hospitals to develop in-house research capabilities in conjunction with industry and academia.

Methods

Data related to research practices in the APAC region were collected from busy cath labs (at least 250 angioplasty/year) and analysed. Results were shared with research experts to understand the challenges in institutional research and create a roadmap for hospitals to develop research capabilities.

Results

A total of 220 respondents from 62 cath labs (88.6%) across 13 APAC countries participated in the survey. A wide variation was noted in research culture across APAC countries. Well-established infrastructure was reported in Australia, New Zealand, South Korea, Singapore, and Japan. Large multicentre trials were common in South Korea, while routine follow-ups were common in Japan. Linking medical records across hospitals/states was considered challenging. Research exposure and training were limited in the APAC region. The experts suggested a roadmap, including creating a conducive regulatory environment, forming synergistic goals, training programs for the professionals involved in research, and leveraging best practices, for improving the research culture in APAC.

Conclusions

Clinical research in cardiology has grown significantly in the APAC region, with a huge research potential in China and India. Implementing measures to improve research training and involvement of the industry will boost the research culture in the APAC region.

Impact of Intensity of Vascular Care Preceding Major Amputation Among Patients With Chronic Limb-Threatening Ischemia

BACKGROUND

Lower-limb amputation rates in patients with chronic limb-threatening ischemia vary across the United States, with marked disparities in amputation rates by gender, race, and income status. We evaluated the association of patient, hospital, and geographic characteristics with the intensity of vascular care received the year before a major lower-limb amputation and how intensity of care associates with outcomes after amputation.

METHODS

Using Medicare claims data (2016-2019), beneficiaries diagnosed with chronic limb-threatening ischemia who underwent a major lower-limb amputation were identified. We examined patient, hospital, and geographic characteristics associated with the intensity of vascular care received the year before amputation. Secondary objectives evaluated all-cause mortality and adverse events following amputation.

RESULTS

Of 33 036 total Medicare beneficiaries undergoing major amputation, 7885 (23.9%) were due to chronic limb-threatening ischemia; of these, 4988 (63.3%) received low-intensity and 2897 (36.7%) received high-intensity vascular care. Mean age, 76.6 years; women, 38.9%; Black adults, 24.5%; and of low income, 35.2%. After multivariable adjustment, those of low income (odds ratio, 0.65 [95% CI, 0.58-0.72]; P<0.001), and to a lesser extent, men (odds ratio, 0.89 [95% CI, 0.81-0.98]; P=0.019), and those who received care at a safety-net hospital (odds ratio, 0.87 [95% CI, 0.78-0.97]; P=0.012) were most likely to receive low intensity of care before amputation. High-intensity care was associated with a lower risk of all-cause mortality 2 years following amputation (hazard ratio, 0.79 [95% CI, 0.74-0.85]; P<0.001).

CONCLUSIONS

Patients who were of low-income status, and to a lesser extent, men, or those cared for at safety-net hospitals were most likely to receive low-intensity vascular care. Low-intensity care was associated with worse long-term event-free survival. These data emphasize the continued disparities that exist in contemporary vascular practice.

Rationale and design of the pullback pressure gradient (PPG) global registry

INTRODUCTION

Diffuse disease has been identified as one of the main reasons leading to low post-PCI fractional flow reserve (FFR) and residual angina after PCI. Coronary pressure pullbacks allow for the evaluation of hemodynamic coronary artery disease (CAD) patterns. The pullback pressure gradient (PPG) is a novel metric that quantifies the distribution and magnitude of pressure losses along the coronary artery in a focal-to-diffuse continuum.

AIM

The primary objective is to determine the predictive capacity of the PPG for post-PCI FFR.

METHODS

This prospective, large-scale, controlled, investigator-initiated, multicenter study is enrolling patients with at least 1 lesion in a major epicardial vessel with a distal FFR ≤ 0.80 intended to be treated by PCI. The study will include 982 subjects. A standardized physiological assessment will be performed pre-PCI, including the online calculation of PPG from FFR pullbacks performed manually. PPG quantifies the CAD pattern by combining several parameters from the FFR pullback curve. Post-PCI physiology will be recorded using a standardized protocol with FFR pullbacks. We hypothesize that PPG will predict optimal PCI results (post-PCI FFR ≥ 0.88) with an area under the ROC curve (AUC) ≥ 0.80. Secondary objectives include patient-reported and clinical outcomes in patients with focal vs. diffuse CAD defined by the PPG. Clinical follow-up will be collected for up to 36 months, and an independent clinical event committee will adjudicate events.

RESULTS

Recruitment is ongoing and is expected to be completed in the second half of 2023.

CONCLUSION

This international, large-scale, prospective study with pre-specified powered hypotheses will determine the ability of the preprocedural PPG index to predict optimal revascularization assessed by post-PCI FFR. In addition, it will evaluate the impact of PPG on treatment decisions and the predictive performance of PPG for angina relief and clinical outcomes.

Artificial Intelligence, Computational Simulations, and Extended Reality in Cardiovascular Interventions

Artificial intelligence, computational simulations, and extended reality, among other 21st century computational technologies, are changing the health care system. To collectively highlight the most recent advances and benefits of artificial intelligence, computational simulations, and extended reality in cardiovascular therapies, we coined the abbreviation AISER. The review particularly focuses on the following applications of AISER: 1) preprocedural planning and clinical decision making; 2) virtual clinical trials, and cardiovascular device research, development, and regulatory approval; and 3) education and training of interventional health care professionals and medical technology innovators. We also discuss the obstacles and constraints associated with the application of AISER technologies, as well as the proposed solutions. Interventional health care professionals, computer scientists, biomedical engineers, experts in bioinformatics and visualization, the device industry, ethics committees, and regulatory agencies are expected to streamline the use of AISER technologies in cardiovascular interventions and medicine in general.

Optical Coherence Tomography-Guided versus Angiography-Guided PCI

BACKGROUND

Data regarding clinical outcomes after optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) as compared with angiography-guided PCI are limited.

METHODS

In this prospective, randomized, single-blind trial, we randomly assigned patients with medication-treated diabetes or complex coronary-artery lesions to undergo OCT-guided PCI or angiography-guided PCI. A final blinded OCT procedure was performed in patients in the angiography group. The two primary efficacy end points were the minimum stent area after PCI as assessed with OCT and target-vessel failure at 2 years, defined as a composite of death from cardiac causes, target-vessel myocardial infarction, or ischemia-driven target-vessel revascularization. Safety was also assessed.

RESULTS

The trial was conducted at 80 sites in 18 countries. A total of 2487 patients underwent randomization: 1233 patients were assigned to undergo OCT-guided PCI, and 1254 to undergo angiography-guided PCI. The minimum stent area after PCI was 5.72±2.04 mm2 in the OCT group and 5.36±1.87 mm2 in the angiography group (mean difference, 0.36 mm2; 95% confidence interval [CI], 0.21 to 0.51; P<0.001). Target-vessel failure within 2 years occurred in 88 patients in the OCT group and in 99 patients in the angiography group (Kaplan-Meier estimates, 7.4% and 8.2%, respectively; hazard ratio, 0.90; 95% CI, 0.67 to 1.19; P = 0.45). OCT-related adverse events occurred in 1 patient in the OCT group and in 2 patients in the angiography group. Stent thrombosis within 2 years occurred in 6 patients (0.5%) in the OCT group and in 17 patients (1.4%) in the angiography group.

CONCLUSIONS

Among patients undergoing PCI, OCT guidance resulted in a larger minimum stent area than angiography guidance, but there was no apparent between-group difference in the percentage of patients with target-vessel failure at 2 years. (Funded by Abbott; ILUMIEN IV: OPTIMAL PCI ClinicalTrials.gov number, NCT03507777.).

Impact of Post-PCI FFR Stratified by Coronary Artery

BACKGROUND

Low fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) has been associated with adverse clinical outcomes. Hitherto, this assessment has been independent of the epicardial vessel interrogated.

OBJECTIVES

This study sought to assess the predictive capacity of post-PCI FFR for target vessel failure (TVF) stratified by coronary artery.

METHODS

We performed a systematic review and individual patient-level data meta-analysis of randomized clinical trials and observational studies with protocol-recommended post-PCI FFR assessment. The difference in post-PCI FFR between left anterior descending (LAD) and non-LAD arteries was assessed using a random-effect models meta-analysis of mean differences. TVF was defined as a composite of cardiac death, target vessel myocardial infarction, and clinically driven target vessel revascularization.

RESULTS

Overall, 3,336 vessels (n = 2,760 patients) with post-PCI FFR measurements were included in 9 studies. The weighted mean post-PCI FFR was 0.89 (95% CI: 0.87-0.90) and differed significantly between coronary vessels (LAD = 0.86; 95% CI: 0.85 to 0.88 vs non-LAD = 0.93; 95% CI: 0.91-0.94; P < 0.001). Post-PCI FFR was an independent predictor of TVF, with its risk increasing by 52% for every reduction of 0.10 FFR units, and this was mainly driven by TVR. The predictive capacity for TVF was poor for LAD arteries (AUC: 0.52; 95% CI: 0.47-0.58) and moderate for non-LAD arteries (AUC: 0.66; 95% CI: 0.59-0.73; LAD vs non-LAD arteries, P = 0.005).

CONCLUSIONS

The LAD is associated with a lower post-PCI FFR than non-LAD arteries, emphasizing the importance of interpreting post-PCI FFR on a vessel-specific basis. Although a higher post-PCI FFR was associated with improved prognosis, its predictive capacity for events differs between the LAD and non-LAD arteries, being poor in the LAD and moderate in the non-LAD vessels.

Standardized Definitions for Cardiogenic Shock Research and Mechanical Circulatory Support Devices: Scientific Expert Panel From the Shock Academic Research Consortium (SHARC)

The Shock Academic Research Consortium is a multi-stakeholder group, including representatives from the US Food and Drug Administration and other government agencies, industry, and payers, convened to develop pragmatic consensus definitions useful for the evaluation of clinical trials enrolling patients with cardiogenic shock, including trials evaluating mechanical circulatory support devices. Several in-person and virtual meetings were convened between 2020 and 2022 to discuss the need for developing the standardized definitions required for evaluation of mechanical circulatory support devices in clinical trials for cardiogenic shock patients. The expert panel identified key concepts and topics by performing literature reviews, including previous clinical trials, while recognizing current challenges and the need to advance evidence-based practice and statistical analysis to support future clinical trials. For each category, a lead (primary) author was assigned to perform a literature search and draft a proposed definition, which was presented to the subgroup. These definitions were further modified after feedback from the expert panel meetings until a consensus was reached. This manuscript summarizes the expert panel recommendations focused on outcome definitions, including efficacy and safety.

Effectiveness and safety of optical coherence tomography-guided PCI in Indian patients with complex lesions: A multicenter, prospective registry

BACKGROUND

Optical coherence tomography (OCT) is reported to be a feasible and safe imaging modality for the guidance of percutaneous coronary intervention (PCI) of complex lesions.

METHODS

This multicenter, prospective registry assessed the minimum stent area (MSA) achieved under OCT guidance. A performance goal of 24% improvement in MSA over and above the recommendation set by the European Association of Percutaneous Cardiovascular Interventions Consensus 2018 (4.5 mm2 MSA for non-left main and 3.5 mm2 for small vessels). The incidence of contrast-induced nephropathy was also assessed. Core lab analysis was conducted.

RESULTS

Five hundred patients (average age: 59.4 ± 10.1 years; 83% males) with unstable angina (36.8%), NSTEMI (26.4%), and STEMI (22%) were enrolled. The primary endpoint was achieved in 93% of lesions with stent diameter ≥2.75 mm (average MSA: 6.44 mm2) and 87% of lesions with stent diameter ≤2.5 mm (average MSA: 4.56 mm2). The average MSA (with expansion ≥80% cutoff) was 6.63 mm2 and 4.74 mm2 with a stent diameter ≥2.75 mm and ≤2.5 mm, respectively. According to the core lab analysis, the average MSA achieved with a stent diameter ≥2.75 mm and ≤2.5 mm was 6.23 mm2 and 3.95 mm2, respectively (with expansion ≥80% cutoff). Clinically significant serum creatinine was noted in two patients (0.45%). Major adverse cardiac events at 1 year were noted in 1.2% (n = 6) of the patients; all were cardiac deaths.

CONCLUSION

PCI under OCT guidance improves procedural and long-term clinical outcomes in patients with complex lesions not just in a controlled trial environment but also in routine clinical practice.

Utility of optical coherence tomography in acute coronary syndromes

Studies utilizing intravascular imaging have replicated the findings of histopathological studies, identifying the most common substrates for acute coronary syndromes (ACS) as plaque rupture, erosion, and calcified nodule, with spontaneous coronary artery dissection, coronary artery spasm, and coronary embolism constituting the less common etiologies. The purpose of this review is to summarize the data from clinical studies that have used high-resolution intravascular optical coherence tomography (OCT) to assess culprit plaque morphology in ACS. In addition, we discuss the utility of intravascular OCT for effective treatment of patients presenting with ACS, including the possibility of culprit lesion-based treatment by percutaneous coronary intervention.

Five-Year Clinical Outcomes After Coronary Bioresorbable Scaffolds and Drug-Eluting Stents: The ABSORB IV Randomized Trial

BACKGROUND

Bioresorbable vascular scaffolds (BVS) were designed to improve late event-free survival compared with metallic drug-eluting stents. However, initial trials demonstrated worse early outcomes with BVS, in part due to suboptimal technique. In the large-scale, blinded ABSORB IV trial, polymeric everolimus-eluting BVS implanted with improved technique demonstrated non-inferior 1-year outcomes compared with cobalt chromium everolimus-eluting stents (CoCr-EES).

OBJECTIVES

To evaluate the long-term outcomes from the ABSORB IV trial.

METHODS

We randomized 2,604 patients at 147 sites with stable or acute coronary syndromes to BVS with improved technique vs. CoCr-EES. Patients, clinical assessors and event adjudicators were blinded to randomization. Five-year follow-up was completed.

RESULTS

Target lesion failure (TLF) at 5 years occurred in 216 patients (17.5%) assigned to BVS and 180 patients (14.5%) assigned to CoCr-EES (P=0.03). Device thrombosis within 5 years occurred in 21 (1.7%) BVS and 13 (1.1%) CoCr-EES patients (P=0.15). Event rates were slightly greater with BVS than CoCr-EES through 3-year follow-up and similar between 3-5 years. Angina, also centrally adjudicated, recurred within 5 years in 659 patients (cumulative rate 53.0%) assigned to BVS and 674 patients (53.3%) assigned to CoCr-EES (P=0.63).

CONCLUSIONS

In this large-scale, blinded randomized trial, despite improved implantation technique the absolute 5-year rate of TLF was 3% greater after BVS compared with CoCr-EES. The risk period for increased events was restricted to 3 years, the time point of complete scaffold bioresorption; event rates were similar thereafter. Angina recurrence after intervention was frequent during 5-year follow-up but was comparable with both devices.

Prognostic impact of fractional flow reserve measurements in patients with acute coronary syndromes: a subanalysis of the FLORIDA study

Randomized trials suggest benefits for fractional flow reserve (FFR)-guided vs. angiography-guided treatment strategies in well-defined and selected patient cohorts with acute coronary syndromes (ACS). The long-term prognostic value of FFR measurement in unselected all-comer ACS patients, however, remains unknown. This subanalysis of the Fractional FLOw Reserve In cardiovascular DiseAses (FLORIDA) study sought to investigate the long-term effects of FFR in the management of lesions in patients with acute coronary syndrome (ACS). FLORIDA was an observational all-comer cohort study performed in Germany, that was population-based and unselected. Patients enrolled into the anonymized InGef Research Database presenting with ACS and undergoing coronary angiography between January 2014 and December 2015 were included in the analysis. Patients were stratified into either the FFR-guided or the angiography-guided treatment arm, based on the treatment received. A matched cohort study design was used. The primary endpoint was all-cause mortality. The secondary endpoint was major adverse cardiovascular events (MACE), a composite of death, non-fatal myocardial infarction (MI), and repeat revascularization. Follow-up time was 3 years. Rates of 3-year mortality were 10.2 and 14.0% in the FFR-guided and the angiography-guided treatment arms (p = 0.04), corresponding to a 27% relative risk reduction for FFR in ACS patients. Rates of MACE were similar in both arms (47.7 vs. 51.5%, p = 0.14), including similar rates of non-fatal MI (27.7 vs. 25.4%, p = 0.47) and revascularization (9.9 vs. 12.1%, p = 0.17). In this large, all-comer observational study of ACS patients, FFR-guided revascularization was associated with a lower mortality at 3 years. This finding encourages the routine use of FFR to guide lesion revascularization in patients presenting with ACS.

Clinical use of optical coherence tomography during percutaneous coronary intervention and coronary procedures in Southeast Asia: a survey-based expert consensus summary

Optical coherence tomography (OCT), an established intravascular imaging technique, enables rapid acquisition of high-resolution images during invasive coronary procedures to assist physician decision-making. OCT has utility in identifying plaque/lesion morphology (e.g., thrombus, degree of calcification, and presence of lipid) and vessel geometry (lesion length and vessel diameter) and in guiding stent optimisation through identification of malapposition and underexpansion. The use of OCT guidance during percutaneous coronary interventions (PCI) has demonstrated improved procedural and clinical outcomes in longitudinal registries, although randomised controlled trial data remain pending. Despite growing data and guideline endorsement to support OCT guidance during PCI, its use in different countries is not well established. This article is based on an advisory panel meeting that included experts from Southeast Asia (SEA) and is aimed at understanding the current clinical utility of intracoronary imaging and OCT, assessing the barriers and enablers of imaging and OCT adoption, and mapping a path for the future of intravascular imaging in SEA. This is the first Southeast Asian consensus that provides insights into the use of OCT from a clinician's point of view.

Safety and efficiency of percutaneous coronary intervention using a standardised optical coherence tomography workflow

BACKGROUND

While intravascular imaging guidance during percutaneous coronary intervention (PCI) improves outcomes, routine intravascular imaging usage remains low, in part due to perceived inefficiency and safety concerns.  Aims: The LightLab (LL) Initiative was designed to evaluate whether implementing a standardised optical coherence tomography (OCT) workflow impacts PCI safety metrics and procedural efficiency.

METHODS

In this multicentre, prospective, observational study, PCI procedural data were collected over 2 years from 45 physicians at 17 US centres. OCT-guided PCI incorporating the LL workflow (N=264), a structured algorithm using routine pre- and post-PCI OCT imaging, was compared with baseline angiography-only PCI (angio) (N=428). Propensity score analysis identified 207 matched procedures. Outcomes included procedure time, radiation exposure, contrast volume, device utilisation, and treatment strategy.

RESULTS

Compared with angiography alone, LL workflow OCT-guided PCI increased the median procedural time by 9 minutes but reduced vessel preparation time (2 min LL workflow vs 3 min angio; p<0.001) and resulted in less unplanned additional treatment (4% LL workflow vs 10% angio; p=0.01). With LL workflow OCT guidance, fewer cineangiography views were needed compared to angiography guidance, leading to decreased radiation exposure (1,133 mGy LL workflow vs 1,269 mGy angio; p=0.02), with no difference in contrast utilisation between groups (p=0.28). Furthermore, LL workflow OCT guidance resulted in fewer predilatation balloons and stents being used, more direct stent placement, and greater stent post-dilatation than angiography-guided PCI.

CONCLUSIONS

The incorporation of a standardised pre- and post-PCI OCT imaging workflow improves procedural efficiency and safety metrics, at a cost of a modestly longer procedure time.

Visualizing Inside Conduits-Intraoperative Screening of Grafts by Optical Coherence Tomography

PURPOSE

Saphenous vein graft (SVG) failure is a complex phenomenon, with technical, biologic, and local factors contributing to early and medium- and long-term failure after coronary artery bypass graft. Both technical and conduit factors may have significant impact on early SVG failure.

DESCRIPTION

We review the complex factors that play a pathogenic role in SVG failure, followed by review of the existing literature on potential utility of high-definition optical coherence tomography (OCT) in comprehensive intraoperative assessment of SVGs.

EVALUATION

We describe a new technique for intraoperative acquisition of OCT images in the harvested SVGs and introduce a classification system for pathologic processes that can be detected in the harvested SVG conduits by OCT.

CONCLUSIONS

The potential impact on early graft failure of the exclusion of segments of SVGs that are less than optimal (ie, containing fibroatheroma, retained thrombus, sclerotic valves, or procurement injury) will be examined in the randomized controlled OCTOCAB (Intraoperative Optical Coherence Tomography of the Saphenous Vein Conduit in Patients Undergoing Coronary Artery Bypass Surgery) trial.

The future of personalized care for vascular patients: an industry perspective

Healthcare has entered a brave new world in the early part of the 21st century: the landscape has changed and continues to change rapidly, evolving at a rate as never seen before. Fuelled by technological advancement, big data analytics, and the explosion of apps and sensors, as well as by telemedicine and remote monitoring needs driven by the COVID-19 pandemic, the healthcare ecosystem is metamorphosing literally before our eyes. So, what is the role for the Medtech industry as healthcare systems reshape themselves to address emerging patients’ needs and desires, and how can the use of data and novel technologies be leveraged to bring about the kind of change needed to deliver truly holistic patient care?

Investigating real-world impact of optical coherence tomography workflow-guided coronary interventions: Design and rationale of the LightLab Clinical Initiative

OBJECTIVE

The LightLab Clinical Initiative was designed to examine adoption of optical coherence tomography (OCT) imaging during routine percutaneous coronary intervention (PCI) practice, and enable identification and reduction of barriers to broader adoption of intracoronary imaging in real-world practice.

BACKGROUND

Intracoronary imaging guidance during PCI has been shown to improve clinical outcomes and features as a recommendation in societal guidelines, yet widespread routine adoption remains low. Perceived barriers to utilization include familiarity with, and ability to interpret imaging, concerns over added procedure time and contrast load, alongside a lack of actionable outcome data.

METHODS AND RESULTS

LightLab was a multicenter prospective observational data-gathering project, conducted between January 2019, and June 2021, with 17 participating hospitals and physicians. Data were gathered in real-time, where OCT guidance was employed during PCI using a standardized OCT-guided workflow algorithm, MLD MAX (where MLD stands for plaque Morphology, lesion Length, vessel Diameter and MAX for Medial dissection, stent Apposition, stent eXpansion) which was developed to simplify and integrate information from OCT throughout the PCI procedure. Integration of this workflow/algorithm was implemented through a series of phases, focusing on physician decision-making, efficiency, and safety improvements during the procedure.

CONCLUSIONS

Through real-time, prospective procedural data acquisition in the cardiac catheterization laboratory setting, the LightLab Clinical Initiative demonstrates the impact of a standardized OCT-guided workflow on procedural metrics, including time, contrast use, radiation exposure, as well as financial efficiencies such as device utilization. These results can potentially mitigate underlying concerns over the utility of adoption of intracoronary imaging guidance during PCI.

Optical coherence tomography versus angiography and intravascular ultrasound to guide coronary stent implantation: A systematic review and meta-analysis

BACKGROUND

Optical coherence tomography (OCT) is an adjunct to angiography-guided coronary stent placement. However, in the absence of dedicated, appropriately powered randomized controlled trials, the impact of OCT on clinical outcomes is unclear.

OBJECTIVE

To conduct a systematic review and meta-analysis of all available studies comparing OCT-guided versus angiography-guided and intravascular ultrasound (IVUS)-guided coronary stent implantation.

METHODS

MEDLINE and Cochrane Central were queried from their inception through July 2022 for all studies that sought to compare OCT-guided percutaneous coronary intervention (PCI) to angiography-guided and IVUS-guided PCI. The primary endpoint was minimal stent area (MSA) compared between modalities. Clinical endpoints of interest were all-cause and cardiovascular mortality, major adverse cardiovascular events (MACE), myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and stent thrombosis (ST). Risk ratios (RRs) and mean differences (MDs) with their corresponding 95% confidence intervals (CIs) were pooled using a random-effects model.

RESULTS

Thirteen studies (8 randomized control trials and 5 observational studies) enrolling 6312 participants were included. OCT was associated with a strong trend toward increased MSA compared to angiography (MD = 0.36, p = 0.06). OCT-guided PCI was also associated with a reduction in the incidence of all-cause mortality [RR = 0.59, 95% CI (0.35, 0.97), p = 0.04] and cardiovascular mortality [RR = 0.41, 95% CI (0.21, 0.80), p = 0.009] compared with angiography-guided PCI. Point estimates favored OCT relative to angiography in MACE [RR = 0.75, 95% CI (0.47, 1.20), p = 0.22] and MI [RR = 0.75, 95% CI (0.53, 1.07), p = 0.12]. No differences were detected in ST [RR = 0.71, 95% CI (0.21, 2.44), p = 0.58], TLR [RR = 0.71, 95% CI (0.17, 3.05), p = 0.65], or TVR rates [RR = 0.89, 95% CI (0.46, 1.73), p = 0.73]. Compared with IVUS guidance, OCT guidance was associated with a nonsignificant reduction in the MSA (MD = -0.16, p = 0.27). The rates of all-cause and cardiovascular mortality, MACE, MI, TLR, TVR, or ST were similar between OCT-guided and IVUS-guided PCI.

CONCLUSIONS

OCT-guided PCI was associated with reduced all-cause and cardiovascular mortality compared to angiography-guided PCI. These results should be considered hypothesis generating as the mechanisms for the improved outcomes were unclear as no differences were detected in the rates of TLR, TVR, or ST. OCT- and IVUS-guided PCI resulted in similar post-PCI outcomes.

The MLD MAX OCT algorithm: An imaging-based workflow for percutaneous coronary intervention

Although extensive clinical data support the utility of intravascular imaging to guide and optimize outcomes following percutaneous coronary interventions (PCI), clinical adoption remains limited. One of the primary reasons for limited utilization may be a lack of standardization on how to best integrate the data provided by intravascular imaging practically. Optical coherence tomography (OCT) offers a high-resolution intravascular imaging modality with integrated software automation that allows for incorporation of OCT into the routine workflow of PCIs. We suggest use of an algorithm called MLD MAX to incorporate OCT for imaging-guided interventions: the baseline OCT imaging run is intended to facilitate procedural planning and strategizing, consisting of assessment for predominant lesion morphology (M), measurement for stent length (L) and determination of stent diameter (D); the post-PCI OCT imaging run is designated for assessment of need for further optimization of stent result, and consists of analysis for medial dissections (M), adequate stent apposition (A) and stent expansion (X). Incorporation of the MLD MAX algorithm into daily practice guides an efficient and easily-memorable workflow for optimized PCI procedures.

Personalized vascular healthcare: insights from a large international survey

Fragmentation of healthcare systems through limited cross-speciality communication and intermittent, intervention-based care, without insight into follow-up and compliance, results in poor patient experiences and potentially contributes to suboptimal outcomes. Data-driven tools and novel technologies have the capability to address these shortcomings, but insights from all stakeholders in the care continuum remain lacking. A structured online questionnaire was given to respondents (n = 1432) in nine global geographies to investigate attitudes to the use of data and novel technologies in the management of vascular disease. Patients with coronary or peripheral artery disease (n = 961), physicians responsible for their care (n = 345), and administrators/healthcare leaders with responsibility for commissioning/procuring cardiovascular services (n = 126) were included. Narrative themes arising from the survey included patients' desire for more personalized healthcare, shared decision-making, and improved communication. Patients, administrators, and physicians perceived and experienced deficiencies in continuity of care, and all acknowledged the potential for data-driven techniques and novel technologies to address some of these shortcomings. Further, physicians and administrators saw the 'upstream' segment of the care journey-before diagnosis, at point of diagnosis, and when determining treatment-as key to enabling tangible improvements in patient experience and outcomes. Finally, despite acceptance that data sharing is critical to the success of such interventions, there remains persistent issues related to trust and transparency. The current fragmented care continuum could be improved and streamlined through the adoption of advanced data analytics and novel technologies, including diagnostic and monitoring techniques. Such an approach could enable the refocusing of healthcare from intermittent contacts and intervention-only focus to a more holistic patient view.

Improving efficiency and operator proficiency during percutaneous coronary interventions utilizing a standardized optical coherence tomography workflow

OBJECTIVES

This study was designed to compare efficiency and quality metrics between percutaneous coronary intervention (PCI) procedures using optical coherence tomography (OCT) guided by a variable workflow versus a standardized workflow in a real-world population.

BACKGROUND

The LightLab (LL) Initiative was designed to evaluate the impact of a standardized OCT workflow during PCI to address barriers to adoption.

METHODS

The LL Initiative was a multicenter, prospective, observational study. PCI efficiency data were collected from 1/21/19 to 1/8/21 from 45 physicians at 17 US centers. OCT-guided PCIs were compared between baseline phase (variable workflow; N = 383) and the LL workflow utilization phase (N = 447). The LL workflow uses OCT to assess lesion Morphology, Length and Diameter, and then optimize outcomes by correcting for Medial dissection, stent mal-Apposition, and under-eXpansion (MLD MAX). Matching based on propensity scores was used to control for differences between PCIs.

RESULTS

After propensity matching, 291 paired procedures were included. Integration of the LL versus variable workflow resulted in no difference in procedure time (51 min vs. 51 min, p = 0.93). There was a reduction in radiation exposure (1124 mGy vs. 1493 mGy, p < 0.0001) and contrast volume (160 cc vs. 172 cc, p < 0.001). The LL workflow decreased the proportion of underexpanded lesions (34% vs. 54%, p < 0.0001) and improved minimum stent expansion (85% vs. 79%, p < 0.0001). Number of noncompliant balloons used was reduced with the LL workflow. (2.0 vs. 1.7, p < 0.01).

CONCLUSIONS

These data suggest that standardizing imaging with the LL workflow may overcome barriers to imaging and improve PCI outcomes without prolonging procedures.

Position Statement on Vascular Access Safety for Percutaneous Devices in AMI Complicated by Cardiogenic Shock

In the United States, the frequency of using percutaneous mechanical circulatory support devices for acute myocardial infarction complicated by cardiogenic shock is increasing. These devices require large-bore vascular access to provide left, right, or biventricular cardiac support, frequently under urgent/emergent circumstances. Significant technical and logistical variability exists in device insertion, care, and removal in the cardiac catheterization laboratory and in the cardiac intensive care unit. This variability in practice may contribute to adverse outcomes observed in centers that receive patients with cardiogenic shock, who are at higher risk for circulatory insufficiency, venous stasis, bleeding, and arterial hypoperfusion. In this position statement, we aim to: 1) describe the public health impact of bleeding and vascular complications in cardiogenic shock; 2) highlight knowledge gaps for vascular safety and provide a roadmap for a regulatory perspective necessary for advancing the field; 3) propose a minimum core set of process elements, or "vascular safety bundle"; and 4) develop a possible study design for a pragmatic trial platform to evaluate which structured approach to vascular access drives most benefit and prevents vascular and bleeding complications in practice.

Optical coherence tomography in coronary atherosclerosis assessment and intervention

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

Coronary Flow Variations Following Percutaneous Coronary Intervention Affect Diastolic Nonhyperemic Pressure Ratios More Than the Whole Cycle Ratios

Background Post-percutaneous coronary intervention (PCI) fractional flow reserve ≥0.90 is an accepted marker of procedural success, and a cutoff of ≥0.95 has recently been proposed for post-PCI instantaneous wave-free ratio. However, stability of nonhyperemic pressure ratios (NHPRs) post-PCI is not well characterized, and transient reactive submaximal hyperemia post-PCI may affect their precision. We performed this study to assess stability and reproducibility of NHPRs post-PCI. Methods and Results Fifty-seven patients (age, 63.77±10.67 years; men, 71%) underwent hemodynamic assessment immediately post-PCI and then after a recovery period of 10, 20, and 30 minutes and repeated at 3 months. Manual offline analysis was performed to derive resting and hyperemic pressure indexes (Pd/Pa resting pressure gradient, mathematically derived instantaneous wave-free ratio, resting full cycle ratio, and fractional flow reserve) and microcirculatory resistances (basal microvascular resistance and index of microvascular resistance). Transient submaximal hyperemia occurring post-PCI was demonstrated by longer thermodilution time at 30 minutes compared with immediately post-PCI; mean difference of thermodilution time was 0.17 seconds (95% CI, 0.07-0.26 seconds; P=0.04). Basal microcirculatory resistance was also higher at 30 minutes than immediately post-PCI; mean difference of basal microvascular resistance was 10.89 mm Hg.s (95% CI, 2.25-19.52 mm Hg.s; P=0.04). Despite this, group analysis confirmed no significant differences in the values of resting whole cycle pressure ratios (Pd/Pa and resting full cycle ratio) as well as diastolic pressure ratios (diastolic pressure ratio and mathematically derived instantaneous wave-free ratio). Whole cardiac cycle NHPRs demonstrated the best overall stability post-PCI, and 1 in 5 repeated diastolic NHPRs crossed the clinical decision threshold. Conclusions Whole cycle NHPRs demonstrate better reproducibility and clinical precision post-PCI than diastolic NHPRs, possibly because of less perturbation from predominantly diastolic reactive hyperemia and left ventricular stunning. Registration URL: https://clinicaltrials.gov/ct2/show/NCT03502083; Unique identifier: NCT03502083 and URL: https://clinicaltrials.gov/ct2/show/NCT03076476; Unique identifier: NCT03076476.

Hot topics in interventional cardiology: Proceedings from the society for cardiovascular angiography and interventions (SCAI) 2021 think tank

The Society for Cardiovascular Angiography and Interventions (SCAI) Think Tank is a collaborative venture that brings together interventional cardiologists, administrative partners, and select members of the cardiovascular industry community annually for high-level field-wide discussions. The 2021 Think Tank was organized into four parallel sessions reflective of the field of interventional cardiology: (a) coronary intervention, (b) endovascular medicine, (c) structural heart disease, and (d) congenital heart disease. Each session was moderated by a senior content expert and co-moderated by a member of SCAI's Emerging Leader Mentorship program. This document presents the proceedings to the wider cardiovascular community in order to enhance participation in this discussion, create additional dialog from a broader base, and thereby aid SCAI, the industry community and external stakeholders in developing specific action items to move these areas forward.

Adenosine-Induced Coronary Steal Is Observed in Patients Presenting With ST-Segment-Elevation Myocardial Infarction

Background Adenosine is used to treat no-reflow in the infarct-related artery (IRA) during ST-segment-elevation myocardial infarction intervention. However, the physiological effect of adenosine in the IRA is variable. Coronary steal-a reduction of blood flow to the distal coronary bed-can occur in response to adenosine and this is facilitated by collaterals. We investigated the effects of adenosine on coronary flow reserve (CFR) in patients presenting with ST-segment-elevation myocardial infarction to better understand the physiological mechanism underpinning the variable response to adenosine. Methods and Results Pressure-wire assessment of the IRA after percutaneous coronary intervention was performed in 93 patients presenting with ST-segment-elevation myocardial infarction to calculate index of microvascular resistance, CFR, and collateral flow index by pressure. Modified collateral Rentrop grade to the IRA was recorded, as was microvascular obstruction by cardiac magnetic resonance imaging. Coronary steal (CFR <0.9), no change in flow (CFR=0.9-1.1), and hyperemic flow (CFR >1.1) after adenosine occurred in 19 (20%), 15 (16%), and 59 (63%) patients, respectively. Patients with coronary steal had higher modified Rentrop score to the IRA (1 [0, 1.75] versus 0 [0, 1], P<0.001) and a higher collateral flow index by pressure (0.25±0.10 versus 0.15±0.10, P=0.004) than the hyperemic group. The coronary steal group also had significantly higher index of microvascular resistance (61.68 [28.13, 87.04] versus 23.93 [14.67, 37.00], P=0.006) and had more disease (stenosis >50%) in the donor arteries (52.63% versus 22.03%, P=0.02) than the hyperemic group. Conclusions Adenosine-induced coronary steal may be responsible for a reduction in coronary flow reserve in a proportion of patients presenting with ST-segment-elevation myocardial infarction. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03145194. URL: https://www.isrctn.com; Unique identifier: ISRCTN3176727.

Vulnerable plaques and patients: state-of-the-art

Despite advanced understanding of the biology of atherosclerosis, coronary heart disease remains the leading cause of death worldwide. Progress has been challenging as half of the individuals who suffer sudden cardiac death do not experience premonitory symptoms. Furthermore, it is well-recognized that also a plaque that does not cause a haemodynamically significant stenosis can trigger a sudden cardiac event, yet the majority of ruptured or eroded plaques remain clinically silent. In the past 30 years since the term 'vulnerable plaque' was introduced, there have been major advances in the understanding of plaque pathogenesis and pathophysiology, shifting from pursuing features of 'vulnerability' of a specific lesion to the more comprehensive goal of identifying patient 'cardiovascular vulnerability'. It has been also recognized that aside a thin-capped, lipid-rich plaque associated with plaque rupture, acute coronary syndromes (ACS) are also caused by plaque erosion underlying between 25% and 60% of ACS nowadays, by calcified nodule or by functional coronary alterations. While there have been advances in preventive strategies and in pharmacotherapy, with improved agents to reduce cholesterol, thrombosis, and inflammation, events continue to occur in patients receiving optimal medical treatment. Although at present the positive predictive value of imaging precursors of the culprit plaques remains too low for clinical relevance, improving coronary plaque imaging may be instrumental in guiding pharmacotherapy intensity and could facilitate optimal allocation of novel, more aggressive, and costly treatment strategies. Recent technical and diagnostic advances justify continuation of interdisciplinary research efforts to improve cardiovascular prognosis by both systemic and 'local' diagnostics and therapies. The present state-of-the-art document aims to present and critically appraise the latest evidence, developments, and future perspectives in detection, prevention, and treatment of 'high-risk' plaques occurring in 'vulnerable' patients.

GLP-1 vasodilatation in humans with coronary artery disease is not adenosine mediated

BACKGROUND

Incretin therapies appear to provide cardioprotection and improve cardiovascular outcomes in patients with diabetes, but the mechanism of this effect remains elusive. We have previously shown that glucagon-like peptide (GLP)-1 is a coronary vasodilator and we sought to investigate if this is an adenosine-mediated effect.

METHODS

We recruited 41 patients having percutaneous coronary intervention (PCI) for stable angina and allocated them into four groups administering a specific study-related infusion following successful PCI: GLP-1 infusion (Group G) (n = 10); Placebo, normal saline infusion (Group P) (n = 11); GLP-1 + Theophylline infusion (Group GT) (n = 10); and Theophylline infusion (Group T) (n = 10). A pressure wire assessment of coronary distal pressure and flow velocity (thermodilution transit time-Tmn) at rest and hyperaemia was performed after PCI and repeated following the study infusion to derive basal and index of microvascular resistance (BMR and IMR).

RESULTS

There were no significant differences in the demographics of patients recruited to our study. Most of the patients were not diabetic. GLP-1 caused significant reduction of resting Tmn that was not attenuated by theophylline: mean delta Tmn (SD) group G - 0.23 s (0.27) versus group GT - 0.18 s (0.37), p = 0.65. Theophylline alone (group T) did not significantly alter resting flow velocity compared to group GT: delta Tmn in group T 0.04 s (0.15), p = 0.30. The resulting decrease in BMR observed in group G persisted in group GT: - 20.83 mmHg s (24.54 vs. - 21.20 mmHg s (30.41), p = 0.97. GLP-1 did not increase circulating adenosine levels in group GT more than group T: delta median adenosine - 2.0 ng/ml (- 117.1, 14.8) versus - 0.5 ng/ml (- 19.6, 9.4); p = 0.60.

CONCLUSION

The vasodilatory effect of GLP-1 is not abolished by theophylline and GLP-1 does not increase adenosine levels, indicating an adenosine-independent mechanism of GLP-1 coronary vasodilatation.

TRIAL REGISTRATION

The local research ethics committee approved the study (National Research Ethics Service-NRES Committee, East of England): REC reference 14/EE/0018. The study was performed according to institutional guidelines, was registered on http://www.clinicaltrials.gov (unique identifier: NCT03502083) and the study conformed to the principles outlined in the Declaration of Helsinki.

Impact of the COVID-19 pandemic: a perspective from industry

The global COVID-19 pandemic has led to unprecedented change throughout society.1 As the articles in this supplement outline, all segments of the broader cardiovascular community have been forced to adapt, to change models of care delivery, and to evolve and innovate in order to deliver optimal management for cardiovascular patients. The medtech/device industry has not been exempt from such change and has been forced to navigate direct and indirect COVID-associated disruption, with effects felt from supply chain logistics to the entire product lifecycle, from the running of clinical trials to new device approvals and managing training, proctoring and congresses in an increasingly-online world. This sea-change in circumstances itself has enforced the industry, in effect, to disrupt its own processes, models and activities. Whilst some of these changes may be temporary, many will endure for some time and some will doubtless become permanent; one thing is for sure: the healthcare ecosystem, including the medical device industry, will never look quite the same again. Although the pandemic has brought a short- to medium-term medical crisis to many countries, its role as a powerful disruptor cannot be underestimated, and may indeed prove to be a force for long-term good, given the accelerated innovation and rapid adaptation that it has cultivated.

GLP-1 Is a Coronary Artery Vasodilator in Humans

Background

The mechanism underlying the beneficial cardiovascular effects of the incretin GLP‐1 (glucagon‐like peptide 1) and its analogues in humans is elusive. We hypothesized that activating receptors located on vascular smooth muscle cells to induce either peripheral or coronary vasodilatation mediates the cardiovascular effect of GLP‐1.

Methods and Results

Ten stable patients with angina awaiting left anterior descending artery stenting underwent forearm blood flow measurement using forearm plethysmography and post–percutaneous coronary intervention coronary blood flow measurement using a pressure‐flow wire before and after peripheral GLP‐1 administration. Coronary sinus and artery bloods were sampled for GLP‐1 levels. A further 11 control patients received saline rather than GLP‐1 in the coronary blood flow protocol. GLP‐1 receptor (GLP‐1R) expression was assessed by immunohistochemistry using a specific GLP‐1R monoclonal antibody in human tissue to inform the physiological studies. There was no effect of GLP‐1 on absolute forearm blood flow or forearm blood flow ratio after GLP‐1, systemic hemodynamics were not affected, and no binding of GLP‐1R monoclonal antibody was detected in vascular tissue. GLP‐1 reduced resting coronary transit time (mean [SD], 0.87 [0.39] versus 0.63 [0.27] seconds; P=0.02) and basal microcirculatory resistance (mean [SD], 76.3 [37.9] versus 55.4 [30.4] mm Hg/s; P=0.02), whereas in controls, there was an increase in transit time (mean [SD], 0.48 [0.24] versus 0.83 [0.41] seconds; P<0.001) and basal microcirculatory resistance (mean [SD], 45.9 [34.7] versus 66.7 [37.2] mm Hg/s; P=0.02). GLP‐1R monoclonal antibody binding was confirmed in ventricular tissue but not in vascular tissue, and transmyocardial GLP‐1 extraction was observed.

Conclusions

GLP‐1 causes coronary microvascular dilation and increased flow but does not influence peripheral tone. GLP‐1R immunohistochemistry suggests that GLP‐1 coronary vasodilatation is indirectly mediated by ventricular‐coronary cross talk.

Glucagon-Like Peptide-1-Mediated Cardioprotection Does Not Reduce Right Ventricular Stunning and Cumulative Ischemic Dysfunction After Coronary Balloon Occlusion

•

GLP-1 protects against ischemic left ventricular dysfunction after serial coronary balloon occlusion of the left anterior descending artery

•

This study assessed whether serial right coronary artery balloon occlusion affected the right ventricle in a similar fashion using a conductance catheter method

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Serial balloon occlusion of the right coronary artery causes stunning and cumulative ischemic dysfunction in the right ventricle

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GLP-1 did not protect against stunning and cumulative ischemic dysfunction in the right ventricle

Stunning and cumulative ischemic dysfunction occur in the left ventricle with coronary balloon occlusion. Glucagon-like peptide (GLP)-1 protects the left ventricle against this dysfunction. This study used a conductance catheter method to evaluate whether the right ventricle (RV) developed similar dysfunction during right coronary artery balloon occlusion and whether GLP-1 was protective. In this study, the RV underwent significant stunning and cumulative ischemic dysfunction with right coronary artery balloon occlusion. However, GLP-1 did not protect the RV against this dysfunction when infused after balloon occlusion.

Clinical outcomes of bioresorbable vascular scaffolds implanted with routine versus selective optical coherence tomography guidance: results from a single-centre experience

AIMS

We aimed to investigate the effects of an initial learning period with mandatory optical coherence tomography (OCT) guidance for the implantation of everolimus-eluting bioresorbable vascular scaffolds (BVS).

METHODS AND RESULTS

We analysed procedural and clinical outcomes of all BVS implantations at a single centre where OCT guidance was mandatory in the initial rollout (OCT-mandatory) phase. We compared these data with the later phase where use of OCT was at operator discretion (OCT-selective or angiography). We implanted 406 BVS in 306 vessels (201 OCT, 105 angiography) in 272 patients. Follow-up duration was 38±10 months. Annualised rates of device-oriented cardiac events (DOCE) and scaffold thrombosis (ScT) were 1.4% and 0.4%, respectively. The risks of DOCE (HR 1.06, 95% CI: 0.33-3.34; p=0.71) and ScT (HR 0.48, 95% CI: 0.07-3.85; p=0.49) were not significantly different when comparing the OCT and angiography groups.

CONCLUSIONS

Routine use of OCT to guide and optimise BVS implants results in very acceptable outcomes. Further, the benefits of such an early OCT-mandatory "learning" period persist after cessation of routine OCT usage when imaging is not routinely used. A period of mandatory OCT usage for BVS implants may therefore be beneficial in improving patient outcomes with these devices.

Absorb Bioresorbable Scaffold Versus Xience Metallic Stent for Prevention of Restenosis Following Percutaneous Coronary Intervention in Patients at High Risk of Restenosis: Rationale and Design of the COMPARE ABSORB Trial

BACKGROUND

The advent of bioresorbable vascular scaffolds (BVS) was considered as a potential improvement in percutaneous coronary intervention (PCI) after the groundbreaking development of drug eluting stents (DES). However, the clinical performance, long-term safety and efficacy of BVS in complex coronary lesions remain uncertain. COMPARE ABSORB, a multicenter, single blind, prospective randomized trial, aims to compare the clinical outcomes between the Absorb BVS and Xience everolimus-eluting metallic stent (EES) in patients with coronary artery disease and a high risk of restenosis.

DESIGN

COMPARE ABSORB is designed to enroll 2100 patients at up to 45 European sites. Enrolled patients will possess high risk for restenosis due to clinical profile or coronary lesion complexity and will undergo elective or emergent PCI. Once included in the study, patients will receive either Absorb BVS or Xience EES. Specific advice on implantation technique including mandatory pre-dilatation, sizing and post-dilatation (PSP), will be used in the Absorb BVS arm. The primary endpoint is target lesion failure (TLF), a device-oriented composite endpoint (cardiac death, target vessel myocardial infarction and clinically-indicated target lesion revascularization). The trial is powered to assess non-inferiority of Absorb BVS compared with Xience EES with a predetermined non-inferiority margin of 4.5% at 1 year after index procedure. The clinical follow-up will continue for 7 years.

CONCLUSIONS

The prospective COMPARE ABSORB randomized trial (ClinicalTrials.govNCT02486068) will help to assess the long-term safety and efficacy of Absorb BVS compared with Xience EES in the treatments of patients with complex coronary artery disease and a high attendant risk of restenosis.

Fractional flow reserve in acute coronary syndrome: a meta-analysis and systematic review

Background

The utility of fractional flow reserve (FFR) to guide revascularisation in the management of acute coronary syndrome (ACS) remains unclear.

Objective

This study aims to compare the clinical outcomes of patients following FFR-guided revascularisation for either ACS or stable angina (SA) and in particular focuses on the outcome of those with deferred revascularisation after FFR.

Methods

A meta-analysis of existing literature was performed. Outcomes including the rate of major adverse cardiovascular events (MACE), recurrent myocardial infarction (MI), mortality and unplanned revascularisation were analysed.

Results

A review of 937 records yielded 9 studies comparing 5457 patients, which were included in the analyses. Patients with ACS had a higher rate of recurrent MI (OR 1.81, p=0.02) and a strong trend towards more MACE and all-cause mortality compared with patients with SA when treated by an FFR-guided revascularisation strategy. Deferral of invasive therapy on the basis of FFR led to a higher rate of MACE (17.6% vs 7.3 %; p=0.004), recurrent MI (5.3% vs 1.5%, p=0.001) and target vessel revascularisation (16.4% vs 5.6 %; p=0.02) in patients with ACS, and a strong trend towards a higher cardiovascular mortality at follow-up when compared with patients with SA.

Conclusion

The event rate in patients with ACS is much higher than SA despite following an FFR-guided revascularisation strategy. Deferring revascularisation does not appear to be as safe for ACS as it is for SA using contemporary FFR cut-offs validated in SA. Refinement of the therapeutic strategy for patients with ACS with multivessel disease is needed to redress the balance.

Biodegradable-Polymer Versus Polymer-Free Drug-Eluting Stents for the Treatment of Coronary Artery Disease

BACKGROUND/PURPOSE

Biodegradable-polymer (BP) and polymer-free (PF) drug eluting stents (DES) were developed to reduce the risk of delayed arterial healing observed with durable-polymer (DP) platforms. Although trials demonstrate BP-DES and PF-DES are non-inferior to DP-DES, there is limited data directly comparing these technologies. We performed a meta-analysis to assess the efficacy and safety of BP-DES versus PF-DES for the treatment of coronary artery disease.

METHODS/MATERIALS

Electronic searches were performed identifying randomized trials comparing BP-DES with PF-DES. Co-primary efficacy endpoints were target vessel revascularization (TVR), target lesion revascularization (TLR) and angiographic in-stent late lumen loss (LLL). Co-secondary safety endpoints were all-cause death, myocardial infarction (MI) and stent thrombosis (ST).

RESULTS

Of 208 studies, 5 met inclusion criteria including 1975 patients. At mean follow-up (14 ± 5 months), BP-DES were associated with significantly reduced rates of TVR (OR 0.58, 95%CI 0.37-0.92, p = 0.02), TLR (4.7% vs 9.5%) (OR 0.48, 95%CI 0.31-0.75, p = 0.001) and in-stent LLL (pooled mean difference -0.20 mm, 95%CI -0.24 to -0.16, p < 0.001). There was no difference in safety, including all-cause death (OR 1.24, 95%CI 0.68-2.28, p = 0.48), MI (OR 0.92, 95%CI 0.54-1.56, p = 0.75) or ST (OR 1.58, 95%CI 0.67-3.73, p = 0.30).

CONCLUSIONS

These data suggests that BP-DES are more efficacious when compared with PF-DES for the treatment of CAD.

High-Risk Atherosclerotic Plaque in Aberrant Circumflex Coronary Artery

A 45-year-old man presented after an episode of central chest pain. Catheter angiography revealed an aberrant circumflex artery and high-grade stenosis in the mid RCA and proximal CX arteries. Previous case series have suggested that the retroaortic portion of aberrant circumflex arteries may be particularly prone to the development of atherosclerosis.

Acute and one-year clinical outcomes following implantation of bioresorbable vascular scaffolds: the ABSORB UK Registry

AIMS

The aim of this registry was to monitor practice patterns and outcomes in patients treated with Absorb bioresorbable vascular scaffolds (BVS) during the early phase of usage in the UK.

METHODS AND RESULTS

A total of 1,005 patients with de novo coronary lesions were treated using careful implantation techniques at 24 centres. Follow-up at one year was obtained in 99%. An independent clinical events committee and angiographic core lab adjudicated all events. Patient age was 52 years and 46% presented with acute coronary syndromes. Lesion complexity was B2/C in 47.4%, with an average of 1.4±0.6 BVS implanted and a BVS length of 28±14.3 mm. A single BVS was implanted in 71.3%. High pressure post-dilatation was performed in 94.9%, with 50% using intravascular imaging. Device success was achieved in 98.7% and procedure success in 97.3% of patients. At one year, the device-oriented endpoint target lesion failure was 3.2%, and the patient-oriented endpoint major adverse cardiac events was 3.4%. Definite ST occurred in 1.4%. By multivariable analysis, scaffold size of 2.5 mm predicted ST at one year (OR 3.27, 95% CI: 1.28-8.37; p=0.014).

CONCLUSIONS

With careful patient selection and technique, TLF rates following BVS implantation in real-world practice are comparable with contemporary drug-eluting stents. ST rates remain high, with small vessel size identified as a contributory factor.

Plaque Rupture in Coronary Atherosclerosis Is Associated With Increased Plaque Structural Stress

OBJECTIVES

The aim of this study was to identify the determinants of plaque structural stress (PSS) and the relationship between PSS and plaques with rupture.

BACKGROUND

Plaque rupture is the most common cause of myocardial infarction, occurring particularly in higher risk lesions such as fibroatheromas. However, prospective intravascular ultrasound-virtual histology studies indicate that <10% higher risk plaques cause clinical events over 3 years, indicating that other factors also determine plaque rupture. Plaque rupture occurs when PSS exceeds its mechanical strength; however, the determinants of PSS and its association with plaques with proven rupture are not known.

METHODS

We analyzed plaque structure and composition in 4,053 virtual histology intravascular ultrasound frames from 32 fibroatheromas with rupture from the intravascular ultrasound-virtual histology in Vulnerable Atherosclerosis study and 32 fibroatheromas without rupture on optical coherence tomography from a stable angina cohort. Mechanical loading in the periluminal region was estimated by calculating maximum principal PSS by finite element analysis.

RESULTS

PSS increased with increasing lumen area (r = 0.46; p = 0.001), lumen eccentricity (r = 0.32; p = 0.001), and necrotic core ≥10% (r = 0.12; p = 0.001), but reduced when dense calcium was ≥10% (r = -0.12; p = 0.001). Ruptured fibroatheromas showed higher PSS (133 kPa [quartiles 1 to 3: 90 to 191 kPa] vs. 104 kPa [quartiles 1 to 3: 75 to 142 kPa]; p = 0.002) and variation in PSS (55 kPa [quartiles 1 to 3: 37 to 75 kPa] vs. 43 kPa [quartiles 1 to 3: 34 to 59 kPa]; p = 0.002) than nonruptured fibroatheromas, with rupture primarily occurring either proximal or immediately adjacent to the minimal luminal area (87.5% vs. 12.5%; p = 0.001). PSS was higher in segments proximal to the rupture site (143 kPa [quartiles 1 to 3: 101 to 200 kPa] vs. 120 kPa [quartiles 1 to 3: 78 to 180 kPa]; p = 0.001) versus distal segments, associated with increased necrotic core (19.1% [quartiles 1 to 3: 11% to 29%] vs. 14.3% [quartiles 1 to 3: 8% to 23%]; p = 0.001) but reduced fibrous/fibrofatty tissue (63.6% [quartiles 1 to 3: 46% to 78%] vs. 72.7% [quartiles 1 to 3: 54% to 86%]; p = 0.001). PSS >135 kPa was a good predictor of rupture in higher risk regions.

CONCLUSIONS

PSS is determined by plaque composition, plaque architecture, and lumen geometry. PSS and PSS variability are increased in plaques with rupture, particularly at proximal segments. Incorporating PSS into plaque assessment may improve identification of rupture-prone plaques.

Coronary CT angiography features of ruptured and high-risk atherosclerotic plaques: Correlation with intra-vascular ultrasound

Background

Features of ruptured and high-risk plaque have been described on coronary computed tomography angiography (coronary CTA), but not systematically assessed against intravascular ultrasound (IVUS). We examined the ability of coronary CTA to identify IVUS defined ruptured plaque and Virtual Histology Intravascular Ultrasound (VH-IVUS) defined thin-cap fibroatheroma (TCFA).

Methods

Sixty-three patients (32 with acute coronary syndrome and 31 with stable angina) underwent coronary CTA, IVUS and VH-IVUS. Plaque rupture on CTA was defined as intra-plaque contrast and its frequency compared with IVUS-defined plaque rupture. We then examined the relationship of conventional coronary CTA high-risk features (low attenuation plaque, positive remodeling, spotty calcification and the Napkin-Ring sign) in VH-IVUS-defined TCFA. We compared these with a novel index based on quantifying the ratio of necrotic core to fibrous plaque using x-ray attenuation cut-offs derived from the relationship of plaque to luminal contrast attenuation.

Results

Of the 71 plaques interrogated with IVUS, 39 were ruptured. Coronary CTA correctly detected 13-ruptured plaques with 3 false positives giving high specificity (91%) but low sensitivity (33%). None of the conventional coronary CTA high-risk features were significantly more frequent in the higher-risk (VH-IVUS defined thin-cap) compared with thick-cap fibroatheroma. However, the new index (necrotic core/fibrous plaque ratio) was higher in thin-cap (mean 0.90) vs. thick-cap fibroatheroma (mean 0.59), p < 0.05.

Conclusions

Compared with intravascular ultrasound, coronary CTA identifies ruptured plaque with good specificity but poor sensitivity. We have identified a novel high-risk feature on coronary CTA (necrotic core/fibrous plaque ratio that is associated with VH-IVUS defined-TCFA.

Implantation of bioresorbable vascular scaffolds following acute coronary syndrome is associated with reduced early neointimal growth and strut coverage

AIMS

Registry data have suggested higher than anticipated rates of scaffold thrombosis following bioresorbable vascular scaffold (BVS) implantation. We examined early neointimal growth and strut coverage in BVS to ascertain whether this was affected by clinical presentation.

METHODS AND RESULTS

Patients undergoing optical coherence tomography (OCT)-guided BVS implantation, either for stable angina (SA) or acute coronary syndrome (ACS), were recruited to this observational study. Repeat OCT was performed at follow-up (median 74 days), and scaffolds analysed at 1 mm longitudinal intervals for scaffold/flow area, scaffold apposition, neointimal growth and strut coverage. Twenty-nine BVS were included in the analysis (62% implanted following ACS). There were no differences in baseline patient/lesion characteristics. All BVS achieved >90% predicted scaffold area with only 1.64% of struts classified as incompletely apposed, compared with 0.47% at follow-up (p=0.006). Reductions in mean scaffold (-4.0%, p=0.01) and flow (-8.4%, p<0.001) areas were observed at follow-up, with larger reductions in mean flow area in stable patients (-14.5±14.2 vs. -4.9±7.9%, p=0.03). ACS patients had reduced neointimal growth (0.51±0.18 vs. 0.87±0.37 mm2, p=0.002), and increased percentage of uncovered struts (2.68±1.67 vs. 1.43±0.87%, p=0.015).

CONCLUSIONS

Early neointimal growth and strut coverage are reduced following ACS in patients receiving BVS. These results may, in part, explain the high rates of ST in registry data.

Stunning and Right Ventricular Dysfunction Is Induced by Coronary Balloon Occlusion and Rapid Pacing in Humans: Insights From Right Ventricular Conductance Catheter Studies

Background

We sought to determine whether right ventricular stunning could be detected after supply (during coronary balloon occlusion [BO]) and supply/demand ischemia (induced by rapid pacing [RP] during transcatheter aortic valve replacement) in humans.

Methods and Results

Ten subjects with single‐vessel right coronary artery disease undergoing percutaneous coronary intervention with normal ventricular function were studied in the BO group. Ten subjects undergoing transfemoral transcatheter aortic valve replacement were studied in the RP group. In both, a conductance catheter was placed into the right ventricle, and pressure volume loops were recorded at baseline and for intervals over 15 minutes after a low‐pressure BO for 1 minute or a cumulative duration of RP for up to 1 minute. Ischemia‐induced diastolic dysfunction was seen 1 minute after RP (end‐diastolic pressure [mm Hg]: 8.1±4.2 versus 12.1±4.1, P<0.001) and BO (end‐diastolic pressure [mm Hg]: 8.1±4.0 versus 8.7±4.0, P=0.03). Impairment of systolic and diastolic function after BO remained at 15‐minutes recovery (ejection fraction [%]: 55.7±9.0 versus 47.8±6.3, P<0.01; end‐diastolic pressure [mm Hg]: 8.1±4.0 versus 9.2±3.9, P<0.01). Persistent diastolic dysfunction was also evident in the RP group at 15‐minutes recovery (end‐diastolic pressure [mm Hg]: 8.1±4.1 versus 9.9±4.4, P=0.03) and there was also sustained impairment of load‐independent indices of systolic function at 15 minutes after RP (end‐systolic elastance and ventriculo‐arterial coupling [mm Hg/mL]: 1.25±0.31 versus 0.85±0.43, P<0.01).

Conclusions

RP and right coronary artery balloon occlusion both cause ischemic right ventricular dysfunction with stunning observed later during the procedure. This may have intraoperative implications in patients without right ventricular functional reserve.

Plaque Structural Stress Estimations Improve Prediction of Future Major Adverse Cardiovascular Events After Intracoronary Imaging

BACKGROUND

Although plaque rupture is responsible for most myocardial infarctions, few high-risk plaques identified by intracoronary imaging actually result in future major adverse cardiovascular events (MACE). Nonimaging markers of individual plaque behavior are therefore required. Rupture occurs when plaque structural stress (PSS) exceeds material strength. We therefore assessed whether PSS could predict future MACE in high-risk nonculprit lesions identified on virtual-histology intravascular ultrasound.

METHODS AND RESULTS

Baseline nonculprit lesion features associated with MACE during long-term follow-up (median: 1115 days) were determined in 170 patients undergoing 3-vessel virtual-histology intravascular ultrasound. MACE was associated with plaque burden ≥70% (hazard ratio: 8.6; 95% confidence interval, 2.5-30.6; P<0.001) and minimal luminal area ≤4 mm(2) (hazard ratio: 6.6; 95% confidence interval, 2.1-20.1; P=0.036), although absolute event rates for high-risk lesions remained <10%. PSS derived from virtual-histology intravascular ultrasound was subsequently estimated in nonculprit lesions responsible for MACE (n=22) versus matched control lesions (n=22). PSS showed marked heterogeneity across and between similar lesions but was significantly increased in MACE lesions at high-risk regions, including plaque burden ≥70% (13.9±11.5 versus 10.2±4.7; P<0.001) and thin-cap fibroatheroma (14.0±8.9 versus 11.6±4.5; P=0.02). Furthermore, PSS improved the ability of virtual-histology intravascular ultrasound to predict MACE in plaques with plaque burden ≥70% (adjusted log-rank, P=0.003) and minimal luminal area ≤4 mm(2) (P=0.002). Plaques responsible for MACE had larger superficial calcium inclusions, which acted to increase PSS (P<0.05).

CONCLUSIONS

Baseline PSS is increased in plaques responsible for MACE and improves the ability of intracoronary imaging to predict events. Biomechanical modeling may complement plaque imaging for risk stratification of coronary nonculprit lesions.

Glucagon-like peptide-1 derived cardioprotection does not utilize a KATP-channel dependent pathway: mechanistic insights from human supply and demand ischemia studies

BACKGROUND

Glucagon-like peptide-1 (7-36) amide (GLP-1) protects against stunning and cumulative left ventricular dysfunction in humans. The mechanism remains uncertain but GLP-1 may act by opening mitochondrial K-ATP channels in a similar fashion to ischemic conditioning. We investigated whether blockade of K-ATP channels with glibenclamide abrogated the protective effect of GLP-1 in humans.

METHODS

Thirty-two non-diabetic patients awaiting stenting of the left anterior descending artery (LAD) were allocated into 4 groups (control, glibenclamide, GLP-1, and GLP-1 + glibenclamide). Glibenclamide was given orally prior to the procedure. A left ventricular conductance catheter recorded pressure-volume loops during a 1-min low-pressure balloon occlusion (BO1) of the LAD. GLP-1 or saline was then infused for 30-min followed by a further 1-min balloon occlusion (BO2). In a non-invasive study, 10 non-diabetic patients were randomized to receive two dobutamine stress echocardiograms (DSE) during GLP-1 infusion with or without oral glibenclamide pretreatment.

RESULTS

GLP-1 prevented stunning even with glibenclamide pretreatment; the Δ % dP/dtmax 30-min post-BO1 normalized to baseline after GLP-1: 0.3 ± 6.8 % (p = 0.02) and GLP-1 + glibenclamide: -0.8 ± 9.0 % (p = 0.04) compared to control: -11.5 ± 10.0 %. GLP-1 also reduced cumulative stunning after BO2: -12.8 ± 10.5 % (p = 0.02) as did GLP-1 + glibenclamide: -14.9 ± 9.2 % (p = 0.02) compared to control: -25.7 ± 9.6 %. Glibenclamide alone was no different to control. Glibenclamide pretreatment did not affect global or regional systolic function after GLP-1 at peak DSE stress (EF 74.6 ± 6.4 vs. 74.0 ± 8.0, p = 0.76) or recovery (EF 61.9 ± 5.7 vs. 61.4 ± 5.6, p = 0.74).

CONCLUSIONS

Glibenclamide pretreatment does not abrogate the protective effect of GLP-1 in human models of non-lethal myocardial ischemia. Trial registration Clinicaltrials.gov Unique Identifier: NCT02128022.