Invasive Management of Hypertrophic Cardiomyopathy With Clinically Important Obstruction: Catheter Intervention Is Superior.

Hypertrophic cardiomyopathy is a common inherited cardiac condition where the myocardium progressively thickens in the absence of abnormal loading conditions. Left ventricular hypertrophy often leads to outflow tract obstruction, and this confers significant mortality and morbidity implications. Septal reduction therapies aim to relieve the obstruction in an attempt to reduce the burden of symptoms and potentially improve prognosis. However, both surgical and catheter-based approaches to septal reduction carry risks. At present, international guidelines and expert consensus statements suggest surgical myomectomy is the gold-standard treatment. In this point-counterpoint review, we discuss why in our opinion this recommendation should be reconsidered. We hope to cover the history of catheter based septal reduction therapies and the significant advances made over the last two decades. We also hope to show why we believe the current evidence shows catheter-based alcohol septal ablation is superior to surgical myomectomy.

Routine Pressure Wire Assessment Versus Conventional Angiography in the Management of Patients With Coronary Artery Disease: The RIPCORD 2 Trial.

BACKGROUND: Measurement of fractional flow reserve (FFR) has an established role in guiding percutaneous coronary intervention. We tested the hypothesis that, at the stage of diagnostic invasive coronary angiography, systematic FFR-guided assessment of coronary artery disease would be superior, in terms of resource use and quality of life, to assessment by angiography alone. METHODS: We performed an open-label, randomized, controlled trial in 17 UK centers, recruiting 1100 patients undergoing invasive coronary angiography for the investigation of stable angina or non-ST-segment-elevation myocardial infarction. Patients were randomized to either angiography alone (angiography) or angiography with systematic pressure wire assessment of all epicardial vessels >2.25 mm in diameter (angiography+FFR). The coprimary outcomes assessed at 1 year were National Health Service hospital costs and quality of life. Prespecified secondary outcomes included clinical events. RESULTS: In the angiography+FFR arm, the median number of vessels examined was 4 (interquartile range, 3-5). The median hospital costs were similar: angiography, £4136 (interquartile range, £2613-£7015); and angiography+FFR, £4510 (£2721-£7415; P=0.137). There was no difference in median quality of life using the visual analog scale of the EuroQol EQ-5D-5L: angiography, 75 (interquartile range, 60-87); and angiography+FFR, 75 (interquartile range, 60-90; P=0.88). The number of clinical events was as follows: deaths, 5 versus 8; strokes, 3 versus 4; myocardial infarctions, 23 versus 22; and unplanned revascularizations, 26 versus 33, with a composite hierarchical event rate of 8.7% (48 of 552) for angiography versus 9.5% (52 of 548) for angiography+FFR (P=0.64). CONCLUSIONS: A strategy of systematic FFR assessment compared with angiography alone did not result in a significant reduction in cost or improvement in quality of life. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01070771.

Stroke Rates Following Surgical Versus Percutaneous Coronary Revascularization.

BACKGROUND: Coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) are used for coronary revascularization in patients with multivessel and left main coronary artery disease. Stroke is among the most feared complications of revascularization. Due to its infrequency, studies with large numbers of patients are required to detect differences in stroke rates between CABG and PCI. OBJECTIVES: This study sought to compare rates of stroke after CABG and PCI and the impact of procedural stroke on long-term mortality. METHODS: We performed a collaborative individual patient-data pooled analysis of 11 randomized clinical trials comparing CABG with PCI using stents; ERACI II (Argentine Randomized Study: Coronary Angioplasty With Stenting Versus Coronary Bypass Surgery in Patients With Multiple Vessel Disease) (n = 450), ARTS (Arterial Revascularization Therapy Study) (n = 1,205), MASS II (Medicine, Angioplasty, or Surgery Study) (n = 408), SoS (Stent or Surgery) trial (n = 988), SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) trial (n = 1,800), PRECOMBAT (Bypass Surgery Versus Angioplasty Using Sirolimus-Eluting Stent in Patients With Left Main Coronary Artery Disease) trial (n = 600), FREEDOM (Comparison of Two Treatments for Multivessel Coronary Artery Disease in Individuals With Diabetes) trial (n = 1,900), VA CARDS (Coronary Artery Revascularization in Diabetes) (n = 198), BEST (Bypass Surgery Versus Everolimus-Eluting Stent Implantation for Multivessel Coronary Artery Disease) (n = 880), NOBLE (Percutaneous Coronary Angioplasty Versus Coronary Artery Bypass Grafting in Treatment of Unprotected Left Main Stenosis) trial (n = 1,184), and EXCEL (Evaluation of Xience Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial (n = 1,905). The 30-day and 5-year stroke rates were compared between CABG and PCI using a random effects Cox proportional hazards model, stratified by trial. The impact of stroke on 5-year mortality was explored. RESULTS: The analysis included 11,518 patients randomly assigned to PCI (n = 5,753) or CABG (n = 5,765) with a mean follow-up of 3.8 ± 1.4 years during which a total of 293 strokes occurred. At 30 days, the rate of stroke was 0.4% after PCI and 1.1% after CABG (hazard ratio [HR]: 0.33; 95% confidence interval [CI]: 0.20 to 0.53; p < 0.001). At 5-year follow-up, stroke remained significantly lower after PCI than after CABG (2.6% vs. 3.2%; HR: 0.77; 95% CI: 0.61 to 0.97; p = 0.027). Rates of stroke between 31 days and 5 years were comparable: 2.2% after PCI versus 2.1% after CABG (HR: 1.05; 95% CI: 0.80 to 1.38; p = 0.72). No significant interactions between treatment and baseline clinical or angiographic variables for the 5-year rate of stroke were present, except for diabetic patients (PCI: 2.6% vs. CABG: 4.9%) and nondiabetic patients (PCI: 2.6% vs. CABG: 2.4%) (p for interaction = 0.004). Patients who experienced a stroke within 30 days of the procedure had significantly higher 5-year mortality versus those without a stroke, both after PCI (45.7% vs. 11.1%, p < 0.001) and CABG (41.5% vs. 8.9%, p < 0.001). CONCLUSIONS: This individual patient-data pooled analysis demonstrates that 5-year stroke rates are significantly lower after PCI compared with CABG, driven by a reduced risk of stroke in the 30-day post-procedural period but a similar risk of stroke between 31 days and 5 years. The greater risk of stroke after CABG compared with PCI was confined to patients with multivessel disease and diabetes. Five-year mortality was markedly higher for patients experiencing a stroke within 30 days after revascularization.

Fractional Flow Reserve Derived From Computed Tomographic Angiography in Patients With Multivessel CAD.

BACKGROUND: The functional SYNTAX score (FSS) has been shown to improve the discrimination for major adverse cardiac events compared with the anatomic SYNTAX score (SS) while reducing interobserver variability. However, evidence supporting the noninvasive FSS in patients with multivessel coronary artery disease (CAD) is scarce. OBJECTIVES: The purpose of this study was to assess the feasibility of and validate the noninvasive FSS derived from coronary computed tomography angiography (CTA) with fractional flow reserve (FFRCT) in patients with 3-vessel CAD. METHODS: The CTA-SS was calculated in patients with 3-vessel CAD included in the SYNTAX II (SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery II) study. The noninvasive FSS was determined by including only ischemia-producing lesions (FFRCT ≤0.80). SS derived from different imaging modalities were compared using the Bland-Altman and Passing-Bablok method, and the agreement on the SS tertiles was investigated with Cohen's Kappa. The risk reclassification was compared between the noninvasive and invasive physiological assessment, and the diagnostic accuracy of FFRCT was assessed by the area under the receiver-operating characteristic curve using instantaneous wave-free ratio as a reference. RESULTS: The CTA-SS was feasible in 86% of patients (66 of 77), whereas the noninvasive FSS was feasible in 80% (53 of 66). The anatomic SS was overestimated by CTA compared with conventional angiography (27.6 ± 6.4 vs. 25.3 ± 6.9; p < 0.0001) whereas the calculation of the FSS yielded similar results between the noninvasive and invasive imaging modalities (21.6 ± 7.8 vs. 21.2 ± 8.8; p = 0.589). The noninvasive FSS reclassified 30% of patients from the high- and intermediate-SS tertiles to the low-risk tertile, whereas invasive FSS reclassified 23% of patients from the high- and intermediate-SS tertiles to the low-risk tertile. The agreement on the classic SS tertiles based on Kappa statistics was slight for the anatomic SS (Kappa = 0.19) and fair for the FSS (Kappa = 0.32). The diagnostic accuracy of FFRCT to detect functional significant stenosis based on an instantaneous wave-free ratio ≤0.89 revealed an area under the receiver-operating characteristics curve of 0.85 (95% CI: 0.79 to 0.90) with a sensitivity of 95% (95% CI: 89% to 98%), specificity of 61% (95% CI: 48% to 73%), positive predictive value of 81% (95% CI: 76% to 86%), and negative predictive value of 87% (95% CI: 74% to 94%). CONCLUSIONS: Calculation of the noninvasive FSS is feasible and yielded similar results to those obtained with invasive pressure-wire assessment. The agreement on the SYNTAX score tertile classification improved with the inclusion of the functional component from slight to fair agreement. FFRCT has good accuracy in detecting functionally significant lesions in patients with 3-vessel CAD. (A Trial to Evaluate a New Strategy in the Functional Assessment of 3-Vessel Disease Using SYNTAX II Score in Patients Treated With PCI; NCT02015832).

Mortality after coronary artery bypass grafting versus percutaneous coronary intervention with stenting for coronary artery disease: a pooled analysis of individual patient data.

BACKGROUND: Numerous randomised trials have compared coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) for patients with coronary artery disease. However, no studies have been powered to detect a difference in mortality between the revascularisation strategies. METHODS: We did a systematic review up to July 19, 2017, to identify randomised clinical trials comparing CABG with PCI using stents. Eligible studies included patients with multivessel or left main coronary artery disease who did not present with acute myocardial infarction, did PCI with stents (bare-metal or drug-eluting), and had more than 1 year of follow-up for all-cause mortality. In a collaborative, pooled analysis of individual patient data from the identified trials, we estimated all-cause mortality up to 5 years using Kaplan-Meier analyses and compared PCI with CABG using a random-effects Cox proportional-hazards model stratified by trial. Consistency of treatment effect was explored in subgroup analyses, with subgroups defined according to baseline clinical and anatomical characteristics. FINDINGS: We included 11 randomised trials involving 11 518 patients selected by heart teams who were assigned to PCI (n=5753) or to CABG (n=5765). 976 patients died over a mean follow-up of 3·8 years (SD 1·4). Mean Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) score was 26·0 (SD 9·5), with 1798 (22·1%) of 8138 patients having a SYNTAX score of 33 or higher. 5 year all-cause mortality was 11·2% after PCI and 9·2% after CABG (hazard ratio [HR] 1·20, 95% CI 1·06-1·37; p=0·0038). 5 year all-cause mortality was significantly different between the interventions in patients with multivessel disease (11·5% after PCI vs 8·9% after CABG; HR 1·28, 95% CI 1·09-1·49; p=0·0019), including in those with diabetes (15·5% vs 10·0%; 1·48, 1·19-1·84; p=0·0004), but not in those without diabetes (8·7% vs 8·0%; 1·08, 0·86-1·36; p=0·49). SYNTAX score had a significant effect on the difference between the interventions in multivessel disease. 5 year all-cause mortality was similar between the interventions in patients with left main disease (10·7% after PCI vs 10·5% after CABG; 1·07, 0·87-1·33; p=0·52), regardless of diabetes status and SYNTAX score. INTERPRETATION: CABG had a mortality benefit over PCI in patients with multivessel disease, particularly those with diabetes and higher coronary complexity. No benefit for CABG over PCI was seen in patients with left main disease. Longer follow-up is needed to better define mortality differences between the revascularisation strategies. FUNDING: None.

Clinical outcomes of state-of-the-art percutaneous coronary revascularization in patients with de novo three vessel disease: 1-year results of the SYNTAX II study.

Aims: To investigate if recent technical and procedural developments in percutaneous coronary intervention (PCI) significantly influence outcomes in appropriately selected patients with three-vessel (3VD) coronary artery disease. Methods and results: The SYNTAX II study is a multicenter, all-comers, open-label, single arm study that investigated the impact of a contemporary PCI strategy on clinical outcomes in patients with 3VD in 22 centres from four European countries. The SYNTAX-II strategy includes: heart team decision-making utilizing the SYNTAX Score II (a clinical tool combining anatomical and clinical factors), coronary physiology guided revascularisation, implantation of thin strut bioresorbable-polymer drug-eluting stents, intravascular ultrasound (IVUS) guided stent implantation, contemporary chronic total occlusion revascularisation techniques and guideline-directed medical therapy. The rate of major adverse cardiac and cerebrovascular events (MACCE [composite of all-cause death, cerebrovascular event, any myocardial infarction and any revascularisation]) at one year was compared to a predefined PCI cohort from the original SYNTAX-I trial selected on the basis of equipoise 4-year mortality between CABG and PCI. As an exploratory endpoint, comparisons were made with the historical CABG cohort of the original SYNTAX-I trial. Overall 708 patients were screened and discussed within the heart team; 454 patients were deemed appropriate to undergo PCI. At one year, the SYNTAX-II strategy was superior to the equipoise-derived SYNTAX-I PCI cohort (MACCE SYNTAX-II 10.6% vs. SYNTAX-I 17.4%; HR 0.58, 95% CI 0.39-0.85, P = 0.006). This difference was driven by a significant reduction in the incidence of MI (HR 0.27, 95% CI 0.11-0.70, P = 0.007) and revascularisation (HR 0.57, 95% CI 0.37-0.9, P = 0.015). Rates of all-cause death (HR 0.69, 95% CI 0.27-1.73, P = 0.43) and stroke (HR 0.69, 95% CI 0.10-4.89, P = 0.71) were similar. The rate of definite stent thrombosis was significantly lower in SYNTAX-II (HR 0.26, 95% CI 0.07-0.97, P = 0.045). Conclusion: At one year, clinical outcomes with the SYNTAX-II strategy were associated with improved clinical results compared to the PCI performed in comparable patients from the original SYNTAX-I trial. Longer term follow-up is awaited and a randomized clinical trial with contemporary CABG is warranted. ClinicalTrials.gov Identifier: NCT02015832.

Computed tomography angiography planning identifies the target vessel for optimum infarct location and improves clinical outcome in alcohol septal ablation for hypertrophic obstructive cardiomyopathy.

AIMS: Alcohol septal ablation (ASA) is an established treatment option in hypertrophic obstructive cardiomyopathy (HOCM). ASA is ineffective in some: inaccurate infarct and inability to identify a vessel contribute. We aimed to improve accuracy of infarct using CT angiography guidance and provide a more predictable and satisfactory outcome. METHODS AND RESULTS: Twenty-one successive patients with symptomatic LVOT obstruction refractory to medication underwent CT angiography planning to guide ASA. CT was performed using a dual-source CT system. Alcohol was delivered to the artery identified from CT: in 17/21 this was a sub-branch of a septal artery, in 2/21 the septal vessel was identified from the circumflex artery. Peak gradient improved from 98 (IQR 89.50-111.50) mmHg to 14 (IQR 8.50-22) mmHg (p=0.003). Systolic anterior motion (SAM) improved in 18/20 patients. NYHA class improved by ≥1 in 18/20. Peak VO2 improved from 79.19% of predicted value (±14.01) to 91.62% (±12.02) predicted (p<0.0001). Success at the first procedure is greater with CT guidance, 17/20 vs. 50/75 with traditional methods (pre-CT guidance) (p=0.02); 9/20 had six-month CMR with target septum infarct in all. ASA-related RBBB reduced from 62% to 13% (p=0.0004). CONCLUSIONS: CT angiography planning improves localisation of infarct and procedural success at the first attempt in ASA when compared to traditional methods. Follow-up to six months suggests a symptomatic, functional and haemodynamic improvement.

Coronary bifurcation lesions treated with simple or complex stenting: 5-year survival from patient-level pooled analysis of the Nordic Bifurcation Study and the British Bifurcation Coronary Study.

AIMS: Randomized trials of coronary bifurcation stenting have shown better outcomes from a simple (provisional) strategy rather than a complex (planned two-stent) strategy in terms of short-term efficacy and safety. Here, we report the 5-year all-cause mortality based on pooled patient-level data from two large bifurcation coronary stenting trials with similar methodology: the Nordic Bifurcation Study (NORDIC I) and the British Bifurcation Coronary Study: old, new, and evolving strategies (BBC ONE). METHODS AND RESULTS: Both multicentre randomized trials compared simple (provisional T-stenting) vs. complex (culotte, crush, and T-stenting) techniques, using drug-eluting stents. We analysed all-cause death at 5 years. Data were collected from phone follow-up, hospital records, and national mortality tracking. Follow-up was complete for 890 out of 913 patients (97%). Both Simple and Complex groups were similar in terms of patient and lesion characteristics. Five-year mortality was lower among patients who underwent a simple strategy rather than a complex strategy [17 patients (3.8%) vs. 31 patients (7.0%); P = 0.04]. CONCLUSION: For coronary bifurcation lesions, a provisional single-stent approach appears to be associated with lower long-term mortality than a systematic dual stenting technique.

Radiofrequency ablation of the interventricular septum to treat outflow tract gradients in hypertrophic obstructive cardiomyopathy: a novel use of CARTOSound® technology to guide ablation.

AIMS: Septal reduction is needed for hypertrophic obstructive cardiomyopathy (HOCM) patients with severe left ventricular outflow tract (LVOT) gradients and symptoms despite medication. Myectomy cannot be performed in all. Alcohol septal ablation cannot be performed in 5-15% due to technical difficulties. A method of delivering percutaneous tissue damage to the septum that is not reliant on coronary anatomy is desirable. To directly ablate the interventricular septum at the mitral valve (MV) systolic anterior motion (SAM)-septal contact point using radiofrequency (RF) energy guided by CARTOSound. METHODS AND RESULTS: Five patients underwent RF ablation (RFA); we describe follow-up at 6 months in four patients. Intracardiac echocardiography (ICE) images are merged with CARTO to create a shell of the cardiac chambers. The SAM-septal contact area is marked from ICE images and mapped on to the CARTO shell; this becomes the target for RF delivery. Conduction tissue is mapped and avoided where possible. Twenty-eight to 42 min of RF energy was delivered to the target area using retrograde aortic access and SmartTouch catheters. Resting LVOT gradient improved from 64.2 (±50.6) to 12.3 (±2.5) mmHg. Valsalva/exercise-induced gradient reduced from 93.5 (±30.9) to 23.3 (±8.3) mmHg. Three patients improved New York Heart Association status from III to II, one patient improved from class III to I. Exercise time on bicycle ergometer increased from 612 to 730 s. Cardiac magnetic resonance shows late gadolinium enhancement up to 8 mm depth at LV target myocardium. One patient died following a significant retroperitoneal haemorrhage. CONCLUSION: Radiofrequency ablation using CARTOSound(®) guidance is accurate and effective in treating LVOT gradients in HOCM in this preliminary group of patients.

Intra-cardiac echocardiography in alcohol septal ablation: a prospective comparative study against trans-thoracic echocardiography.

Alcohol septal ablation (ASA) in hypertrophic obstructive cardiomyopathy reduces left ventricular outflow tract gradients. A third of patients do not respond; inaccurate localisation of the iatrogenic infarct can be responsible. Transthoracic echocardiography (TTE) using myocardial contrast can be difficult in the laboratory environment. Intra-cardiac echocardiography (ICE) provides high-quality images. We aimed to assess ICE against TTE in ASA. The ability of ICE and TTE to assess three key domains (mitral valve (MV) anatomy and systolic anterior motion, visualisation of target septum, adjacent structures) was evaluated in 20 consecutive patients undergoing ASA. Two independent experts scored paired TTE and ICE images off line for each domain in both groups. The ability to see myocardial contrast following septal arterial injection was also assessed by the cardiologist performing ASA. In patients undergoing ASA, ICE was superior in viewing MV anatomy (P=0.02). TTE was superior in assessing adjacent structures (P=0.002). There was no difference in assessing target septum. Myocardial contrast: ICE did not clearly identify the area of contrast in 17/19 patients due to dense acoustic shadowing (8/19) and inadequate opacification of the myocardium (6/19). ICE only clearly localised contrast in 2/19 cases. ICE does not visualise myocardial contrast well and therefore cannot be used to guide ASA. TTE was substantially better at viewing myocardial contrast. There was no significant difference between ICE and TTE in the overall ability to comment on cardiac anatomy relevant to ASA.

Intervention in HCM: patient selection, procedural approach and emerging techniques in alcohol septal ablation.

Hypertrophic cardiomyopathy (HCM) is a highly heterogeneous disease with varied patterns of hypertrophy. Basal septal hypertrophy and systolic anterior motion (SAM) of the mitral valve (MV) are the key pathophysiological components to left ventricular outflow tract (LVOT) obstruction in HCM. LVOT is associated with higher morbidity and mortality in patients with HCM. Percutaneous septal reduction therapy with alcohol septal ablation (ASA) can lead to a significant improvement in left ventricle haemodynamics, patient symptoms and perhaps prognosis. ASA delivers pure alcohol to an area of myocardium via septal coronary arteries; this creates damage to tissue akin to a myocardial infarction. The basal septal myocardium involved in SAM-septal contact is the target for this iatrogenic infarct. Appropriate patient selection and accurate delivery of alcohol are critical to safe and effective ASA. Securing the correct diagnosis and ensuring suitable cardiac anatomy are essential before considering ASA. Pre-procedural planning and intra-procedural imaging guidance are important to delivering precise damage to the desired area. The procedure is performed worldwide and is generally safe; the need for a pacemaker is the most prominent complication. It is successful in the majority of patients but room for improvement exists. New techniques have been proposed to perform percutaneous septal reduction. We present a review of the relevant pathophysiology, current methods and a summary of available evidence for ASA. We also provide a glimpse into emerging techniques to deliver percutaneous septal reduction therapy.

Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy: Safe and Apparently Efficacious But Does Reporting of Aggregate Outcomes Hide Less-Favorable Results, Experienced by a Substantial Proportion of Patients?

AIMS: To describe individual and aggregate outcomes for patients undergoing alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM). METHODS: Retrospective case series reviewing all patients undergoing ASA at a United Kingdom tertiary referral center from 2000-2012. Aggregate and individual outcomes are described in terms of symptomatic and hemodynamic response. RESULTS: Eighty-eight patients were reviewed. Alcohol was delivered in 84, with clinical status data available in 82 and hemodynamic data available in 74. All patients had resting or exercise stress left ventricular outflow tract (LVOT) gradient >50 mm Hg. Mean age was 60.3 ± 14.3 years. Follow-up period was 4.2 ± 3.3 years. Twenty-four patients (27%) required ≥2 procedures. Complete heart block was observed in 17%. New York Heart Association (NYHA) class pre ASA was 2.80 ± 0.46, improving to 1.92 ± 0.84 post ASA (P<.001). Fifty-eight out of 82 patients (71%) had improved NYHA class. Resting peak gradient was 99.80 ± 45.86 mm Hg. Post-ASA peak gradient fell to 23.77 ± 41.87 mm Hg (P<.001). Sixty-one out of 74 patients (82%) had successful treatment of LVOT gradient. A successful outcome in both symptomatic and gradient treatment was seen in 66% of patients. No patient who received alcohol suffered sudden cardiac death. Fifteen patients had implantable cardioverter defibrillator implantation; no appropriate therapy was delivered. CONCLUSIONS: ASA is safe, with few major complications. Aggregate outcomes are good, but can hide individual failure. There is a need to refine case selection, procedure planning, and performance to secure more uniform favorable outcomes.

Double jeopardy: multi-modality imaging of monozygotic "twin cap" atherosclerosis.

The investigation of asymptomatic but potentially vulnerable atherosclerosis is not yet a major focus for clinical Cardiologists. We have illustrated the contemporary investigation and treatment of such disease using a clinical case that involved monozygotic twins. One twin (T1) had unfortunately suffered a cardiac arrest whilst jogging and survived only due to bystander CPR and prompt defibrillation. His identical twin brother (T2), on subsequent investigation, harbours a compositionally identical lesion in a proximal coronary vessel that has not yet ruptured or provoked a clinical event. Following the presentation of both non-invasive and invasive images, we discuss the need for active suspicion and intensive treatment for those people with a 'genetic' risk of future myocardial infarction.

Site-specific intravascular ultrasound analysis of remodelling index and calcified necrosis patterns reveals novel blueprints for coronary plaque instability.

AIMS: Post-mortem pathological studies have shown that a "vulnerable" plaque is the dominant patho-physiological mechanism responsible for acute coronary syndromes (ACS). One way to improve our understanding of these plaques in vivo is by using histological "surrogates" created by intravascular ultrasound derived virtual histology (IVUS-VH). Our aim in this analysis was to determine the relationship between site-specific differences in individual plaque areas between ACS plaques and stable plaques (SP), with a focus on remodelling index and the pattern of calcifying necrosis. METHODS AND RESULTS: IVUS-VH was performed before percutaneous intervention in both ACS culprit plaques (CP) n=70 and stable disease (SP) n=35. A total of 210 plaque sites were examined in 105 lesions at the minimum lumen area (MLA) and the maximum necrotic core site (MAX NC). Each plaque site had multiple measurements made including some novel calculations to ascertain the plaque calcification equipoise (PCE) and the calcified interface area (CIA). CP has greater amounts of positive remodelling at the MLA (RI@MLA): 1.1 (±0.17) vs. 0.95 (±0.14) (P<0.001); lower values for PCE 30% vs. 54% (P<0.001) but a higher CIA 5.38 (±2.72) vs. 3.58 (±2.26) (P=0.001). These features can provide discriminatory ability between plaque types with area under the curve (AUC) measurements between 0.65-0.86. The cut-off values with greatest sensitivity and specificity to discriminate CP morphologies were: RI @ MLA >1.12; RI @ MAX NC >1.22; PCE @ MLA <47.1%; PCE @MAX NC <47.3%; CIA @ MLA >2.6; CIA @ MAX NC >3.1. CONCLUSIONS: Determining the stage of calcifying necrosis, along with the remodelling index can discriminate between stable and ACS related plaques. These findings could be applied in the future to help detect plaques that have a vulnerable phenotype.

Construction and validation of a plaque discrimination score from the anatomical and histological differences in coronary atherosclerosis: the Liverpool IVUS-V-HEART (Intra Vascular UltraSound-Virtual-Histology Evaluation of Atherosclerosis Requiring Treatment) study.

AIMS: New markers to help stratify coronary atherosclerosis are needed. Although attempts have been made to differentiate active lesions from those that are stable, none of these has ever been formalised into a discriminatory score. The aim of this study was to analyse the differences between culprit ACS lesions and culprit stable angina lesions with intravascular ultrasound-derived virtual histology and to construct and validate a plaque score. METHODS AND RESULTS: Prior to percutaneous coronary intervention (PCI), we performed volumetric, intravascular ultrasound-derived virtual histology (IVUS-VH) analysis in acute coronary syndrome (ACS) culprit lesions (AC - n=70) and stable angina culprit lesions (SC - n=35). A direct statistical comparison of IVUS-VH data and multiple logistic regression analysis was undertaken. Four main factors were found to be associated (p<0.05) with an AC lesion phenotype: necrotic core/dense calcium (NC/DC) ratio; minimum lumen area <4 mm2 (MLA <4); remodelling index @MLA >1.05 and VH-TCFA presence. Calculation of each logistic regression coefficient and the equation produces an active plaque discrimination score with an AUC of 0.96 on receiver operating characteristics (ROC) analysis. Validation of the score in 50 independent plaques from the Thoraxcenter in Rotterdam revealed an AUC of 0.71, confirming continued diagnostic ability. CONCLUSIONS: We have found four features on IVUS and VH that can predict and discriminate ACS culprit lesion phenotypes from those that are clinically stable. Subsequently, we have constructed and validated the Liverpool Active Plaque Score based upon these features. It is hoped this score may help diagnose active coronary plaques, in the future, to help prevent major adverse cardiac events.

Defining the magnitude of measurement variability in the virtual histology analysis of acute coronary syndrome plaques.

BACKGROUND: Previous intravascular ultrasound-based virtual histology (IVUS-VH) measurement variability studies have been confined to single-frame or short-segment analysis in stable patients with minimal disease. We sought to determine the magnitude of human measurement variability in acute coronary syndrome (ACS) plaques. METHODS AND RESULTS: Prior to percutaneous coronary intervention, we performed IVUS-VH analysis in troponin-positive ACS culprit lesions. A total of 3840 IVUS-VH frames were analysed by two operators to determine intra- and inter-observer variability. The plaque constituent area and volumes were compared using intra-class correlation coefficient (ICC); within-subjects standard deviation (WSSD, mm(2) or mm(3)) and the repeatability coefficient (RCO) to quantify the magnitude of operator error that 95% of future measurements should not exceed. The majority of intra- and inter-observer measurements had ICC of >0.92 confirming excellent agreement. Only the fibrous area (0.86), fibro-fatty (FF) area (0.72) and FF volume (0.87) had ICC levels suggesting an operator error >10%. However, the mean RCO and the percentage this represents in single-frame analysis (area error) varied across the plaque subtypes: fibrous area = 1.64 mm(2) (59%); FF area = 0.49 mm(2) (140%); necrotic core (NC) area = 0.39 mm(2) (21.3%); dense calcium (DC) area = 0.29 mm(2) (33.7%). For full lesion pullbacks (volume error): fibrous volume = 8.14 mm(3) (9.9%); FF volume = 5.63 mm(3) (53.8%); NC volume = 3.78 mm(3) (6.9%) and DC = 2.4 mm(3) (9.6%) CONCLUSION: As in previous studies, intra- and inter-observer ICC suggests good agreement between observers. However, this can still represent large measurement error values and percentages. These findings could impact on the interpretation of previous studies and influence future studies using IVUS-VH measurements as endpoints.