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.

Quantification of patient-specific coronary material properties and their correlations with plaque morphological characteristics: An in vivo IVUS study.

BACKGROUND: A method using in vivo Cine IVUS and VH-IVUS data has been proposed to quantify material properties of coronary plaques. However, correlations between plaque morphological characteristics and mechanical properties have not been studied in vivo. METHOD: In vivo Cine IVUS and VH-IVUS data were acquired at 32 plaque cross-sections from 19 patients. Six morphological factors were extracted for each plaque. These samples were categorized into healthy vessel, fibrous plaque, lipid-rich plaque and calcified plaque for comparisons. Three-dimensional thin-slice models were constructed using VH-IVUS data to quantify in vivo plaque material properties following a finite element updating approach by matching Cine IVUS data. Effective Young's moduli were calculated to represent plaque stiffness for easy comparison. Spearman's rank correlation analysis was performed to identify correlations between plaque stiffness and morphological factor. Kruskal-Wallis test with Bonferroni correction was used to determine whether significant differences in plaque stiffness exist among four plaque groups. RESULT: Our results show that lumen circumference change has a significantly negative correlation with plaque stiffness (r = -0.7807, p = 0.0001). Plaque burden and calcification percent also had significant positive correlations with plaque stiffness (r = 0.5105, p < 0.0272 and r = 0.5312, p < 0.0193) respectively. Among the four categorized groups, calcified plaques had highest stiffness while healthy segments had the lowest. CONCLUSION: There is a close link between plaque morphological characteristics and mechanical properties in vivo. Plaque stiffness tends to be higher as coronary atherosclerosis advances, indicating the potential to assess plaque mechanical properties in vivo based on plaque compositions.

Association of left atrial enlargement and increased left ventricular wall thickness with arrhythmia recurrence after cryoballoon ablation for atrial fibrillation.

BACKGROUND: Left atrial enlargement (LAE) predicts atrial fibrillation (AF) recurrence after cryoballoon-based pulmonary vein isolation (CB). Increased left ventricular wall thickness (LVWT) is pathophysiologically associated with LAE and atrial arrhythmias. AIMS: To assess effect of increased LVWT on long-term outcomes of CB depending on coexistence of LAE. METHODS: LAE was defined using either echocardiography ( > 48 cm³/m²) or multislice computer tomography (MSCT, ≥63 cm³/m²). Increased LVWT was echocardiographic septal/posterior wall thickness > 10 mm in males and > 9 mm in females. All patients achieved 2-year follow-up. RESULTS: Of 250 patients (median [interquartile range, IQR] age of 61 [49.0-67.3] years; 30% female) with AF (40% non-paroxysmal), 66.5% had hypertension, and 27.2% underwent redo procedure. MSCT was done in 76%. During follow-up of 24.5 (IQR, 6.0-31.00) months the clinical success rate was 72%, despite 46% of patients having arrhythmia recurrence. Arrhythmia recurrence risk was increased by LAE and increased LVWT (hazard ratio [HR], 1.801; P = 0.002 and HR, 1.495; P = 0.036; respectively). The highest arrhythmia recurrence (61.9% at 2 years) was among patients with LAE and increased LVWT (33.6% of patients); intermediate (41.8%) among patients with isolated LAE; and lowest among patients with isolated increased LVWT or patients without LAE or increased LVWT (36.8% and 35.2% respectively, P = 0.004). After adjustment for body mass index (BMI), paroxysmal AF, CHA2DS2-VASc score, clinically-significant valvular heart disease, and cardiomyopathy, patients with LAE and concomitant increased LVWT diagnosis had a 1.8-times increased risk of arrhythmia recurrence (HR, 1.784; 95% confidence interval [CI], 1.017-3.130; P = 0.043). CONCLUSION: Joint occurrence of LAE and increased LVWT is associated with the highest rate of arrhythmia recurrence after CB for AF.

Long-Term Clinical Impact of Contrast-Associated Acute Kidney Injury Following PCI: An ADAPT-DES Substudy.

OBJECTIVES: This study sought to determine correlates and consequences of contrast-associated acute kidney injury (CA-AKI) on clinical outcomes in patients with or without pre-existing chronic kidney disease (CKD). BACKGROUND: The incidence and impact of CA-AKI on clinical outcomes during contemporary percutaneous coronary intervention (PCI) are not fully defined. METHODS: The ADAPT-DES (Assessment of Dual AntiPlatelet Therapy With Drug Eluting Stents) study was a prospective, multicenter registry of 8,582 patients treated with ≥1 drug-eluting stent(s). CA-AKI was defined as a post-PCI increase in serum creatinine of >0.5 mg/dL or a relative increase of ≥25% compared with pre-PCI. CKD was defined as estimated glomerular filtration rate <60 mL/min/1.73 m2. The primary endpoint was the 2-year rate of net adverse clinical events (NACE): All-cause mortality, myocardial infarction (MI), definite or probable stent thrombosis, or major bleeding. RESULTS: Of 7287 (85%) patients with evaluable data, 476 (6.5%) developed CA-AKI. In a multivariable model, older age, female sex, Caucasian race, congestive heart failure, diabetes, hypertension, CKD, presentation with ST-segment elevation MI, Killip class II to IV, radial access, intra-aortic balloon pump use, hypotension, and number of stents were independent predictors of CA-AKI. The 2-year NACE rate was higher in patients with CA-AKI (adjusted HR: 1.88; 95% CI: 1.42-2.49), as was each component of NACE (all-cause mortality, HR: 1.77; 95% CI: 1.22-2.55; MI, HR: 1.67; 95% CI: 1.18-2.36; definite/probable stent thrombosis, HR: 1.71; 95% CI: 1.10-2.65; and major bleeding, HR: 1.38; 95% CI: 1.06-1.80). Compared with the CA-AKI-/CKD- group, the CA-AKI+/CKD- (HR: 1.83; 95% CI: 1.33-2.52), CA-AKI-/CKD+ (HR: 1.56; 95% CI: 1.15-2.13), CA-AKI+/CKD+ (HR: 3.29; 95% CI: 1.92-5.67), and maintenance dialysis (HR: 2.67; 95% CI: 1.65-4.31) groups were at higher risk of NACE. CONCLUSIONS: CA-AKI was relatively common after contemporary PCI and was associated with increased 2-year rates of NACE. Patients with pre-existing CKD were at particularly high risk for NACE after CA-AKI.

Clinical determinants of coronary artery disease burden and vulnerability using optical coherence tomography co-registered with intravascular ultrasound.

OBJECTIVES: We investigated clinical determinants of disease burden and vulnerability using optical coherence tomography (OCT) co-registered with intravascular ultrasound (IVUS) in a large cohort of patients. METHODS: A total of 704 patients [44.5% with acute coronary syndromes (ACS)] underwent coronary intervention. IVUS plaque burden and OCT lipid, macrophage and calcium indices and the presence of thrombus, plaque rupture and thin-cap fibroatheroma (TCFA) were analyzed. RESULTS: Median patient age was 66 years with 81.8% men, 34.4% with diabetes mellitus and 15.5% with preadmission statins. Median lesion length was 25.7 mm, and 33.0% had a TCFA. Adjusted models indicated (1) older patient age was related to more calcium, but fewer macrophages; (2) men were related to more thrombus with plaque rupture while women had more thrombus without plaque rupture; (3) ACS presentation was related to morphological acute thrombotic events (more thrombus with/without rupture) and plaque vulnerability (more TCFA, more lipid and macrophages and larger plaque burden); (4) diabetes mellitus was related to a greater atherosclerotic disease burden (more lipid and calcium and larger plaque burden) and more thrombus without rupture; (5) hypertension was related to more macrophages; (6) current smoking was related to less calcium; and (7) renal insufficiency and preadmission statin therapy were not independently associated with IVUS or OCT plaque morphology. CONCLUSION: Patient characteristics, especially diabetes mellitus and aging, affect underlying atherosclerotic burden, among which a greater lipidic burden along with sex differences influence local thrombotic morphology that affects clinical presentation.

Translesional Fractional Flow Reserve is Related to Plaque Components in Coronary Artery Disease: A Study Combining Pressure Wire and NIRS-IVUS Analysis.

OBJECTIVES: It remains unclear whether atherosclerotic plaque structure or composition is related to translesional biomechanical stresses in coronary artery disease. The aim of this study was to evaluate the association between translesional pressure parameters (using a pressure wire) and plaque characteristics (using a combined near-infrared spectroscopy [NIRS] and intravascular ultrasound [IVUS] imaging catheter). METHODS: Fractional flow reserve (FFR), delta (Δ) FFR, and Δ pressure were obtained during adenosine-induced maximum hyperemic status. Lipid core burden index (LCBI) and maximum LCBI within 2 mm (maxLCBI2mm) and tomographic anatomy were evaluated by NIRS-IVUS. RESULTS: Sixty-six lesions from 57 patients were analyzed (57 lesions for FFR, 45 lesions for ΔFFR). There was a negative correlation between FFR and maxLCBI2mm (r=-0.264; P=.049) and a positive correlation between ΔFFR and maxLCBI2mm (r=0.299; P=.049). ΔFFR of lesions with maxLCBI2mm ≥500 was significantly higher than maxLCBI2mm <500 (0.159 ± 0.085 vs 0.104 ± 0.075, respectively; P=.04). By receiver-operating characteristic curve analysis, ΔFFR ≥0.1 was a predictor for maxLCBI2mm ≥500 (area under curve, 0.707; 95% confidence interval, 0.552-0.862; P=.03). On multivariate analysis, ΔFFR was the only predictor of maxLCBI2mm (ß=0.347; P=.03). CONCLUSION: ΔFFR across a coronary artery lesion is related to lipid core burden assessed using NIRS-IVUS and might be a meaningful predictor of high-risk plaque (plaque with high lipid content).

Mechanisms, Prevention and Treatment of Saphenous Vein Graft Disease.

Saphenous vein grafts are imperfect yet indispensable conduits commonly used for coronary artery bypass grafting. Their degeneration ultimately leading to occlusion results from the pathological response of the vein to altered blood rheology and several types of vascular injury. Surgical techniques minimizing vessel damage, and prolonged antiplatelet and lipid-lowering treatment are established methods of mitigating the degeneration process hence preventing graft occlusions. Percutaneous interventions in degenerated vein grafts carry high risk of embolization, periprocedural myocardial infarction and restenosis. Thus, native vessel should be the preferred treatment target in case of graft failure whenever technically feasible.

One-Year Outcomes After Treatment of Ostial In-Stent Restenosis in Left Circumflex Versus Left Anterior Descending or Right Coronary Artery.

The prognosis of left circumflex (LC) versus non-LC in-stent restenosis (ISR) ostial lesions following treatment has not been assessed. We aimed to assess this prognosis. Anecdotally, treatment of ostial LC ISR has been associated with high recurrence rates. We performed a retrospective analysis of patients from our institution who underwent coronary intervention of an ostial ISR lesion between 2003 and 2018. The primary endpoint was target lesion revascularization (TLR) and major adverse cardiovascular events (MACE). Overall, 563 patients underwent ostial ISR lesion intervention, 144 for an ostial LC ISR lesion. Compared to patients with ostial ISR in non-LC lesions, patients with ostial LC ISR were older, had higher rates of diabetes mellitus and previous coronary bypass surgery. At 1-year follow-up, TLR-MACE rates were 26.6% in the LC group versus 18.4% in the non-LC group (p = 0.036). The TLR rate was also higher in the LC group compared to the non-LC group (p = 0.0498). Univariate and multivariate analyses demonstrated a higher TLR-MACE rate for LC versus non-LC ostial ISR lesions. In conclusion, our study shows increased event rates after treatment of LC versus non-LC ISR lesions. Further studies should be done to assess the optimal treatment approach for ostial LC ISR.

Left coronary artery calcification patterns after coronary bypass graft surgery: An in-vivo optical coherence tomography study.

OBJECTIVES: We sought to evaluate the severity and patterns of calcifications in the left main coronary artery (LMCA) and proximal segments of left anterior descending coronary artery (LAD) and left circumflex artery (LCX) using optical coherence tomography (OCT) in patients with and without prior coronary artery bypass grafting (CABG). BACKGROUND: CABG may accelerate upstream calcium development. METHODS: OCT images (n = 76) of the LMCA bifurcation from either the LAD or LCX in 76 patients with at least one patent left coronary graft, on average 7.0 ± 5.6 years post-CABG, were compared with 148 OCT images in propensity-score-matched non-CABG controls. RESULTS: Minimum lumen areas in the LMCA, LAD, and LCX in post-CABG patients were smaller than non-CABG controls. Maximum calcium arc and thickness as well as calcium length were greater in the LMCA and LCX, but not in the LAD in post-CABG patients versus non-CABG controls. Calcium located at the carina of a bifurcation, calcified nodules (CN), thin intimal calcium, and lobulated calcium were more prevalent in post-CABG patients. After adjusting for multiple covariates, prior CABG was an independent predictor of calcification at the carina of a bifurcation (odds ratio [OR] 5.77 [95% confidence interval, CI: 1.5-21.6]), thin intimal calcium (4.7 [1.5-14.4]), and the presence of a CN (15.60 [3.2-76.2]). CONCLUSIONS: Prior CABG is associated with greater amount of calcium in the LMCA and the proximal LCX, as well as higher prevalence of atypical calcium patterns, including CN, thin or lobulated calcium, and calcifications located at the carina of a bifurcation, compared with non-CABG controls.

Predictors of non-stenting strategy for acute coronary syndrome caused by plaque erosion: four-year outcomes of the EROSION study.

BACKGROUND: The EROSION study demonstrated that patients with an acute coronary syndrome (ACS) caused by plaque erosion could be treated with antithrombotic therapy without stenting. However, the long-term prognosis of this strategy is still unclear. AIMS: The aim of this study was to test whether a non-stenting antithrombotic strategy was still effective at four-year follow-up and to explore potential predictors of long-term prognosis. METHODS: This study was a long-term follow-up of the EROSION study. Follow-up was conducted by phone call or clinical visit. Patients were divided into two groups - those with target lesion revascularisation (the TLR group), and the non-TLR group. RESULTS: Out of 55 patients who completed one-month follow-up, 52 patients finished four-year follow-up. The median duration was 4.8 years (range, 4.2-5.8 years). The majority of patients remained free from events, and all patients were free from hard endpoints (death, myocardial infarction, stroke, bypass surgery, or heart failure). Only one patient had gastrointestinal bleeding, and 11 patients underwent TLR. Patients in the non-TLR group had more optical coherence tomography (OCT) thrombus reduction from baseline to one month; 95% of patients in the non-TLR group versus 45% in the TLR group (p=0.001) met the primary endpoint (thrombus volume reduction >50%). Angiographic results showed that the TLR group had less improvement in diameter stenosis (p=0.014) at one month compared with the non-TLR group. CONCLUSIONS: Four-year follow-up findings reconfirmed the safety of an antithrombotic therapy without stenting for ACS caused by erosion. Patients with better response to antithrombotic therapy in the first month were less likely to require stent implantation during the next four years.

The IMPact on Revascularization Outcomes of intraVascular ultrasound-guided treatment of complex lesions and Economic impact (IMPROVE) trial: Study design and rationale.

Intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) has been shown in clinical trials, registries, and meta-analyses to reduce recurrent major adverse cardiovascular events after PCI. However, IVUS utilization remains low. An increasing number of high-risk or complex coronary artery lesions are treated with PCI, and we hypothesize that the impact of IVUS in guiding treatment of these complex lesions will be of increased importance in reducing major adverse cardiovascular events while remaining cost-effective. The "IMPact on Revascularization Outcomes of intraVascular ultrasound-guided treatment of complex lesions and Economic impact" trial (registered on clinicaltrials.gov: NCT04221815) is a multicenter, international, clinical trial randomizing subjects to IVUS-guided versus angiography-guided PCI in a 1:1 ratio. Patients undergoing PCI involving a complex lesion are eligible for enrollment. Complex lesion is defined as involving at least 1 of the following characteristics: chronic total occlusion, in-stent restenosis, severe coronary artery calcification, long lesion (≥28 mm), or bifurcation lesion. The clinical investigation will be conducted at approximately 120 centers in North America and Europe, enrolling approximately 2,500 to 3,100 randomized subjects with an adaptive design. The primary clinical end point is the rate of target vessel failure at 12 months, defined as the composite of cardiac death, target vessel-related myocardial infarction, and ischemia-driven target vessel revascularization. The co-primary imaging end point is the final post-PCI minimum stent area assessed by IVUS. The primary objective of this study is to assess the impact of IVUS guidance on the PCI treatment of complex lesions.

Impact of Intravascular Ultrasound on Outcomes Following PErcutaneous Coronary InterventioN in Complex Lesions (iOPEN Complex).

BACKGROUND: Clinical data support the use of intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) as being associated with improved outcomes. Nonetheless, global utilization of IVUS remains low. We hypothesize that, in the revascularization of complex lesions, IVUS use is associated with improved outcomes. METHODS: All patients with complex lesions treated with PCI at a single center from 2003 to 2016 were stratified by use of IVUS. Complex lesions were defined as follows: American College of Cardiology/American Heart Association type C lesions, in-stent restenosis, long lesions, bifurcations, severe calcification, left main lesions, and chronic total occlusions. The primary end point was the rate of major adverse cardiac events (MACE) at 1-year follow-up, defined as the composite of all-cause mortality, Q-wave myocardial infarction, and target vessel revascularization. Inverse probability weighting was used in the adjusted analysis. RESULTS: A total of 6,855 patients were included in the final analysis, of whom 67.3% had IVUS and 32.7% had angiography alone. The primary end point occurred in 13.4% of patients treated with IVUS and 18.3% of patients treated with angiography alone (P < .001). Inverse probability weighting-adjusted 1-year MACE rates demonstrated significant reduction with IVUS for each complex lesion type. CONCLUSIONS: Among patients with complex lesions, the use of IVUS was associated with lower MACE 1 year after PCI than angiography alone was. Because of the increased procedural risk in complex lesions, routine utilization of IVUS-guided PCI should be considered in this subset of patients.

Intravascular ultrasound guidance improves patient survival (mortality) after drug-eluting stent implantation: review and updated bibliography.

Individual studies IVUS vs angiography-guided DES implantation studies, whether randomized clinical trials or registries are underpowered, to show a reduction in mortality, especially at 1 year of follow-up. However, either meta-analyses or the few studies with long-term (> 5 year) follow-up showed that IVUS guidance reduced mortality and improved patient survival, even with second-generation DES.

The Smoker's Paradox Revisited: A Patient-Level Pooled Analysis of 18 Randomized Controlled Trials.

OBJECTIVES: This study examined the smoker's paradox using patient-level data from 18 prospective, randomized trials of patients undergoing percutaneous coronary intervention (PCI) with stent implantation. BACKGROUND: Studies on the effects of smoking and outcomes among patients undergoing PCI have reported conflicting results. METHODS: Data from the RAVEL, E-SIRIUS, SIRIUS, C-SIRIUS, TAXUS IV and V, ENDEAVOR II to IV, SPIRIT II to IV, HORIZONS-AMI, COMPARE I and II, PLATINUM, and TWENTE I and II randomized trials were pooled. Patients were stratified by smoking status at time of enrollment. The 1- and 5-year ischemic outcomes were compared. RESULTS: Among 24,354 patients with available data on smoking status, 6,722 (27.6%) were current smokers. Smokers were younger and less likely to have diabetes mellitus; hypertension; hyperlipidemia; or prior myocardial infarction (MI), PCI, or coronary artery bypass grafting. Angiographically, smokers had longer lesions, more complex lesions, and more occlusions, but were less likely to have moderate or severe calcification or tortuosity. At 5 years, smokers had significantly higher rates of MI (7.8% vs. 5.6%; p < 0.0001) and definite or probable stent thrombosis (3.5% vs. 1.8%; p < 0.0001); however, there were no differences in the rates of death, cardiac death, target lesion revascularization, or composite endpoints (cardiac death, target vessel MI, or ischemic target lesion revascularization). After multivariable adjustment for potential confounders, smoking was a strong independent predictor of death (hazard ratio [HR]: 1.86; 95% confidence interval [CI]: 1.63 to 2.12; p < 0.0001), cardiac death (HR: 1.68; 95% CI: 1.38 to 2.05; p < 0.0001), MI (HR: 1.38; 95% CI: 1.20 to 1.58; p < 0.0001), stent thrombosis (HR: 1.60; 95% CI: 1.28 to 1.99; p < 0.0001), and target lesion failure (HR: 1.17; 95% CI: 1.05 to 1.30; p = 0.005). CONCLUSIONS: The present large, patient-level, pooled analysis with 5-year follow-up clearly demonstrates smoking to be an important predictor of adverse outcomes after PCI.

Ultra-low-contrast angiography in patients with advanced chronic kidney disease and previous coronary artery bypass surgery.

OBJECTIVE: We sought to describe a technique for ultra-low-contrast angiography (ULCA) in patients with advanced chronic kidney disease (CKD) and previous coronary artery bypass surgery (CABG). BACKGROUND: Patients with advanced CKD and previous CABG are at high risk of developing contrast-induced nephropathy (CIN) because of the additional contrast often required to identify bypass grafts. Apart from hydration, reduced contrast administration is the only established method to minimize the risk of CIN. PATIENTS AND METHODS: Ten patients underwent ULCA, whereby an intracoronary injection of saline and coronary guidewires were used instead of test injections of contrast for engagement of bypass grafts with catheters. Estimated glomerular filtration rate (eGFR) before and 30 days following angiography were recorded as was the need for renal replacement therapy 1 year after the procedure. RESULTS: All patients completed a diagnostic angiogram without complications. The median volume of contrast delivered was 13.5 ml (interquartile range: 10.5-17.8). The median eGFR was 18.3 ml/min/1.73 m (interquartile range: 16.5-28.2). There was no statistically significant difference in eGFR before the procedure and 30 days after the procedure (P=0.79). No patient required dialysis 30 days after the procedure. Two patients required initiation of dialysis at 1 year after the procedure. CONCLUSION: In patients with advanced CKD and previous CABG, ULCA may be performed with high procedural success and without complications, minimizing the risk of CIN in these high-risk patients.

Algorithmic Approach for Optical Coherence Tomography-Guided Stent Implantation During Percutaneous Coronary Intervention.

Intravascular imaging plays a key role in optimizing outcomes for percutaneous coronary intervention (PCI). Optical coherence tomography (OCT) utilizes a user-friendly interface and provides high-resolution images. OCT can be used as part of daily practice in all stages of a coronary intervention: baseline lesion assessment, stent selection, and stent optimization. Incorporating a standardized, algorithmic approach when using OCT allows for precision PCI.

Bifurcation and ostial optical coherence tomography mapping (BOOM) - Case description of a novel bifurcation stent technique.

Stent placement guided by angiography alone is often inexact, but of increased importance with bifurcation percutaneous coronary intervention (PCI). We describe a novel technique using optical coherence tomography (OCT)-guided angiographic co-registration termed "Bifurcation and Ostial OCT Mapping" (BOOM). The technique is based on the precise identification and mapping of the side-branch ostium using co-registration to minimize protrusion of stent struts into the main branch while ensuring full coverage of the ostium in the side-branch.