Residual Plaque Burden in Patients With Acute Coronary Syndromes After Successful Percutaneous Coronary Intervention

Evolving concepts of the vulnerable atherosclerotic plaque and the vulnerable patient: implications for patient care and future research

Understanding the natural history of coronary artery atherosclerosis is necessary to determine prognosis and prescribe effective therapies. Traditional management of coronary artery disease has focused on the treatment of flow-limiting anatomical obstructions that lead to ischaemia. In most scenarios, revascularization of these atherosclerotic plaques has not substantially improved freedom from death or myocardial infarction, questioning the utility of contemporary revascularization strategies to improve prognosis. Advances in non-invasive and invasive imaging techniques have helped to identify the characteristics of obstructive and non-obstructive plaques that are precursors for plaque progression and future acute coronary syndromes as well as cardiac death. These 'vulnerable plaques' develop as a consequence of systemic inflammation and are prone to inducing thrombosis. Vulnerable plaques most commonly have a large plaque burden with a well-formed necrotic core and thin fibrous cap and are metabolically active. Perivascular adipose tissue might, in some patients, be used as a surrogate for coronary inflammation and predict future risk of adverse cardiac events. Vulnerable plaques can be identified in their quiescent state, offering the potential for therapeutic passivation. In this Review, we describe the biological and compositional features of vulnerable plaques, the non-invasive and invasive diagnostic modalities to characterize vulnerable plaques, the prognostic utility of identifying vulnerable plaques, and the future studies needed to explore the value of intensified pharmacological and focal treatments of vulnerable plaques.

Risk Stratification of Patients with Acute Coronary Syndrome

Defining the risk factors affecting the prognosis of patients with acute coronary syndrome (ACS) has been a challenge. Many individual biomarkers and risk scores that predict outcomes during different periods following ACS have been proposed. This review evaluates known outcome predictors supported by clinical data in light of the development of new treatment strategies for ACS patients during the last three decades.

High-Risk Morphological and Physiological Coronary Disease Attributes as Outcome Markers After Medical Treatment and Revascularization

OBJECTIVES

This study sought to evaluate the prognostic impact of plaque morphology and coronary physiology on outcomes after medical treatment or percutaneous coronary intervention (PCI).

BACKGROUND

Although fractional flow reserve (FFR) is currently best practice, morphological characteristics of coronary artery disease also contribute to outcomes.

METHODS

A total of 872 vessels in 538 patients were evaluated by invasive FFR and coronary computed tomography angiography. High-risk attributes (HRA) were defined as high-risk physiological attribute (invasive FFR ≤0.8) and high-risk morphological attributes including: 1) local plaque burden (minimum lumen area <4 mm² and plaque burden ≥70%); 2) adverse plaque characteristics ≥2; and 3) global plaque burden (total plaque volume ≥306.5 mm³ and percent atheroma volume ≥32.2%). The primary outcome was the composite of revascularization, myocardial infarction, or cardiac death at 5 years.

RESULTS

The mean FFR was 0.88 ± 0.08, and PCI was performed in 239 vessels. The primary outcome occurred in 54 vessels (6.2%). All high-risk morphological attributes were associated with the increased risk of adverse outcomes after adjustment for FFR ≤0.8 and demonstrated direct prognostic effect not mediated by FFR ≤0.8. The 5-year event risk proportionally increased as the number of HRA increased (p for trend <0.001) with lower risk in the PCI group than the medical treatment group in vessels with 1 or 2 HRA (9.7% vs. 14.7%), but not in vessels with either 0 or ≥3 HRA. Of the vessels with pre-procedural FFR ≤0.8, ischemia relief by PCI (pre-PCI FFR ≤0.8 and post-PCI FFR >0.8) significantly reduced vessel-oriented composite outcome risk compared with medical treatment alone in vessels with 0 or 1 high-risk morphological attributes (hazard ratio: 0.33; 95% confidence interval: 0.12 to 0.93; p = 0.035), but the risk reduction was attenuated in vessels with ≥2 high-risk morphological attributes.

CONCLUSIONS

High-risk morphological attributes offered additive prognostic value to coronary physiology and may optimize selection of treatment strategies by adding to FFR-based risk predictions (CCTA-FFR Registry for Development of Comprehensive Risk Prediction Model; NCT04037163).

Percutaneous Coronary Intervention for Vulnerable Coronary Atherosclerotic Plaque

BACKGROUND

Acute coronary syndromes most commonly arise from thrombosis of lipid-rich coronary atheromas that have large plaque burden despite angiographically appearing mild.

OBJECTIVES

This study sought to examine the outcomes of percutaneous coronary intervention (PCI) of non-flow-limiting vulnerable plaques.

METHODS

Three-vessel imaging was performed with a combination intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) catheter after successful PCI of all flow-limiting coronary lesions in 898 patients presenting with myocardial infarction (MI). Patients with an angiographically nonobstructive stenosis not intended for PCI but with IVUS plaque burden of ≥65% were randomized to treatment of the lesion with a bioresorbable vascular scaffold (BVS) plus guideline-directed medical therapy (GDMT) versus GDMT alone. The primary powered effectiveness endpoint was the IVUS-derived minimum lumen area (MLA) at protocol-driven 25-month follow-up. The primary (nonpowered) safety endpoint was randomized target lesion failure (cardiac death, target vessel-related MI, or clinically driven target lesion revascularization) at 24 months. The secondary (nonpowered) clinical effectiveness endpoint was randomized lesion-related major adverse cardiac events (cardiac death, MI, unstable angina, or progressive angina) at latest follow-up.

RESULTS

A total of 182 patients were randomized (93 BVS, 89 GDMT alone) at 15 centers. The median angiographic diameter stenosis of the randomized lesions was 41.6%; by near-infrared spectroscopy-IVUS, the median plaque burden was 73.7%, the median MLA was 2.9 mm², and the median maximum lipid plaque content was 33.4%. Angiographic follow-up at 25 months was completed in 167 patients (91.8%), and the median clinical follow-up was 4.1 years. The follow-up MLA in BVS-treated lesions was 6.9 ± 2.6 mm² compared with 3.0 ± 1.0 mm² in GDMT alone-treated lesions (least square means difference: 3.9 mm²; 95% confidence interval: 3.3 to 4.5; p < 0.0001). Target lesion failure at 24 months occurred in similar rates of BVS-treated and GDMT alone-treated patients (4.3% vs. 4.5%; p = 0.96). Randomized lesion-related major adverse cardiac events occurred in 4.3% of BVS-treated patients versus 10.7% of GDMT alone-treated patients (odds ratio: 0.38; 95% confidence interval: 0.11 to 1.28; p = 0.12).

CONCLUSIONS

PCI of angiographically mild lesions with large plaque burden was safe, substantially enlarged the follow-up MLA, and was associated with favorable long-term clinical outcomes, warranting the performance of an adequately powered randomized trial. (PROSPECT ABSORB [Providing Regional Observations to Study Predictors of Events in the Coronary Tree II Combined with a Randomized, Controlled, Intervention Trial]; NCT02171065).

How can optical coherence tomography be used to optimize percutaneous coronary intervention?

Optical coherence tomography (OCT) imaging provides high resolution assessment of coronary parietal and endoluminal abnormalities. Clinical evidence and intuitive utilization make this tool relevant for use in daily practice in the catheterization laboratory. In the present review, we summarize the benefits of OCT for the optimization of percutaneous coronary intervention (PCI) in daily practice. First, we focus on the characterization of lesion type with a view to anticipating challenges during PCI. Then, we describe the utility of OCT to identify culprit lesions and ambiguous angiographic findings. Finally, we outline targets for optimization after PCI and the mechanisms underlying stent failure.

Clinical implications of three-vessel fractional flow reserve measurement in patients with coronary artery disease

Aims

There are limited data on the clinical implications of total physiologic atherosclerotic burden assessed by invasive physiologic studies in patients with coronary artery disease. We investigated the prognostic implications of total physiologic atherosclerotic burden assessed by total sum of fractional flow reserve (FFR) in three vessels (3V-FFR).

Methods and results

A total of 1136 patients underwent FFR measurement in three vessels (3V FFR-FRIENDS study, NCT01621438). The patients were classified into high and low 3V-FFR groups according to the median value of 3V-FFR (2.72). The primary endpoint was major adverse cardiac events (MACE, a composite of cardiac death, myocardial infarction and ischaemia-driven revascularization) at 2 years. Mean angiographic percent diameter stenosis and FFR were 43.7 ± 19.3% and 0.90 ± 0.08, respectively. There was a negative correlation between 3V-FFR and estimated 2-year MACE rate (P < 0.001). The patients in low 3V-FFR group showed a higher risk of 2-year MACE than those in the high 3V-FFR group [(7.1% vs. 3.8%, hazard ratio (HR) 2.205, 95% confidence interval (CI) 1.201-4.048, P = 0.011]. The higher 2-year MACE rate was mainly driven by the higher rate of ischaemia-driven revascularization in the low 3V-FFR group (6.2% vs. 2.7%, HR 2.568, 95% CI 1.283-5.140, P = 0.008). In a multivariable adjusted model, low 3V-FFR was an independent predictor of MACE (HR 2.031, 95% CI 1.078-3.830, P = 0.029).

Conclusion

Patients with high total physiologic atherosclerotic burden assessed by 3V-FFR showed higher risk of 2-year clinical events than those with low total physiologic atherosclerotic burden. The difference was mainly driven by ischaemia-driven revascularization for both functionally significant and insignificant lesions at baseline. Three-vessel FFR might be used as a prognostic indicator in patients with coronary artery disease.

Clinical trial registration

3V FFR-FRIENDS study (https://clinicaltrials.gov/ct2/show/NCT01621438, NCT01621438).

Long-term clinical outcomes in patients with untreated non-culprit intermediate coronary lesion and evaluation of predictors by using virtual histology-intravascular ultrasound; a prospective cohort study

Background

It is uncertain whether the coronary lesion with intermediate stenosis is more likely to cause cardiovascular events than a normal or minimal lesion. We conducted a single-center, prospective cohort study to identify long-term clinical outcomes of patients with untreated non-culprit intermediate lesion and evaluate its predictor of cardiovascular events by using virtual histology-intravascular ultrasound (VH-IVUS).

Methods

Subjects with non-culprit intermediate lesion underwent VH-IVUS were prospectively registered after percutaneous coronary intervention at the culprit lesion. Intermediate lesion was defined as 30 to 70% stenosis in coronary angiography and primary outcome was an occurrence of major adverse cardiovascular events (MACE) defined as all-cause death, intermediate lesion revascularization (InLR), minimal lesion revascularization (MnLR, unplanned revascularization elsewhere in the target vessel or in other coronary arteries which looked normal or minimal stenosis), cerebrovascular events, or non-fatal myocardial infarction (MI). The mean follow-up period was 4.2 years.

Results

Total 25 MACE, approximately 7% incidence annually, were identified during a follow-up period in 86 patients with 89 intermediate lesions. InLR (n = 13) was a most common event followed by MnLR (n = 6), non-fatal MI (n = 4), all-cause death (n = 3), and cerebrovascular events (n = 1). Diameter stenosis (OR 1.07, 95% CI 1.01–1.12, p = 0.015), plaque burden (PB, OR 1.07, 95% CI 1.00–1.15, p = 0.040), fibrofatty area (FFA, OR 1.61, 95% CI 1.10–2.38, p = 0.016), PB ≥ 70% (OR 3.93, 95% CI 1.28–12.07, p = 0.018), and area stenosis ≥ 50% (OR 2.94, 95% CI 1.01–8.56, p = 0.042) showed significant relationships with an occurrence of MACE. In multivariable Cox-proportional hazard analysis, FFA in intermediate lesion was an only independent predictor of MACE (HR 1.36, 95% CI 1.05–1.77, p = 0.019).

Conclusions

Untreated intermediate lesions had a significantly higher chance for requiring revascularization compared with a normal or minimal lesion. And also, a large FFA in intermediate lesion was a significant predictor of cardiovascular events and which finding was mainly driven by coronary-related events, in particularly intermediate lesion progression.

Intracoronary near-infrared spectroscopy and the risk of future cardiovascular events

Objectives

The objectives of this study were to investigate if findings by intracoronary near-infrared spectroscopy (NIRS) and intravascular ultrasound (IVUS) are associated with future cardiovascular events and if NIRS can differentiate culprit from non-culprit segments in patients with coronary artery disease.

Methods

The study included 144 patients with coronary artery disease undergoing percutaneous coronary intervention and combined NIRS-IVUS imaging at two Swedish hospitals. The NIRS-derived lipid core burden index (LCBI), the 4 mm segment with maximum LCBI (MaxLCBI4mm) and the IVUS-derived maximum plaque burden (MaxPB) were analysed within the culprit segment and continuous 10 mm non-culprit segments of the index culprit vessels. The association with future major adverse cardiovascular and cerebrovascular events (MACCE), defined as all-cause mortality, acute coronary syndrome requiring revascularisation and cerebrovascular events during follow-up was evaluated using multivariable Cox regressions. A receiver operating characteristic (ROC) analysis was performed to test the ability of NIRS to discriminate culprit against non-culprit segments.

Results

A non-culprit maxLCBI4mm ≥400 (HR: 3.67, 95% CI 1.46 to 9.23, p=0.006) and a non-culprit LCBI ≥ median (HR: 3.08, 95% CI 1.11 to 8.56, p=0.031) were both significantly associated with MACCE, whereas a non-culprit MaxPB ≥70% (HR: 0.61, 95% CI 0.08 to 4.59, p=0.63) was not. The culprit segments had larger lipid cores compared with non-culprit segments (MaxLCBI4mm 425 vs 74, p<0.001), and the ROC analysis showed that NIRS can differentiate culprit against non-culprit segments (c-statistics: 0.85, 95% CI 0.81 to 0.89).

Conclusion

A maxLCBI4mm ≥400 and LCBI ≥ median, assessed by NIRS in non-culprit segments of a culprit artery, were significantly associated with patient-level MACCE. NIRS furthermore adequately discriminated culprit against non-culprit segments in patients with coronary disease.

Comparison of plaque morphology between peripheral and coronary artery disease (from the CLARITY and ADAPT-DES IVUS substudies)

OBJECTIVE

The aim of this study was to help understand the different outcomes when treating peripheral arterial disease (PAD) versus coronary artery disease (CAD). We compared plaque morphology between PAD and CAD using intravascular ultrasound.

METHODS

Complete Lesion Assessment with ffR and IVUS TechnologY (CLARITY) was a prospective, multicenter trial that enrolled 50 PAD patients with a lower extremity wound fed by a tibial or a peroneal artery with diameter stenosis more than 50%. Assessment of Dual AntiPlatelet Therapy With Drug Eluting Stents (ADAPT-DES) was a prospective, multicenter, registry that enrolled 8582 CAD patients. We compared preintervention intravascular ultrasound findings in 42 PAD lesions from CLARITY versus 79 matched CAD lesions from ADAPT-DES.

RESULTS

Compared with CAD lesions, PAD lesions had (i) smaller mean vessel, plaque, and lumen volumes; (ii) twice the lesion length; (iii) greater maximum superficial calcium arc and plaque eccentricity (i.e. there was more concentric plaque) measured at the minimum lumen area site; (iv) calcium arc and plaque eccentricity were positively correlated to plaque burden in both PAD and CAD lesions; and (v) calcium arc and the presence of concentric plaque were greater in PAD compared with CAD independent of the degree of plaque burden.

CONCLUSION

Compared with CAD lesions, PAD lesions in a tibial or a peroneal artery were longer; had more concentric, diffuse, and calcified plaque; and had smaller vessel volumes.

Rationale and design of the Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography IMaging (PARADIGM) registry: A comprehensive exploration of plaque progression and its impact on clinical outcomes from a multicenter serial coronary computed tomographic angiography study

BACKGROUND

The natural history of coronary artery disease (CAD) in patients with low-to-intermediate risk is not well characterized. Although earlier invasive serial studies have documented the progression of atherosclerotic burden, most were focused on high-risk patients only. The PARADIGM registry is a large, prospective, multinational dynamic observational registry of patients undergoing serial coronary computed tomographic angiography (CCTA). The primary aim of PARADIGM is to characterize the natural history of CAD in relation to clinical and laboratory data.

DESIGN

The PARADIGM registry (ClinicalTrials.govNCT02803411) comprises ≥2,000 consecutive patients across 9 cluster sites in 7 countries. PARADIGM sites were chosen on the basis of adequate CCTA volume, site CCTA proficiency, local demographic characteristics, and medical facilities to ensure a broad-based sample of patients. Patients referred for clinically indicated CCTA will be followed up and enrolled if they had a second CCTA scan. Patients will also be followed up beyond serial CCTA performance to identify adverse CAD events that include cardiac and noncardiac death, myocardial infarction, unstable angina, target vessel revascularization, and CAD-related hospitalization.

SUMMARY

The results derived from the PARADIGM registry are anticipated to add incremental insight into the changes in CCTA findings in accordance with the progression or regression of CAD that confer prognostic value beyond demographic and clinical characteristics.

Effects of statin therapy on progression of mild noncalcified coronary plaque assessed by serial coronary computed tomography angiography: A multicenter prospective study

BACKGROUND

There are limited data assessing statin therapy in patients with nonobstructive coronary plaque on coronary computed tomography angiography (CCTA).

METHODS

Two hundred six consecutive patients with mild noncalcified plaque on CCTA were enrolled in this multicenter prospective observational study. Subjects were divided into 3 groups according to subsequent statin therapy: intensive statin therapy (n = 55), moderate statins (n = 85), and no statin (n = 66). Serial scans were performed after a median interval of 18 months. Low-attenuation plaque (LAP) volume, total plaque volume, and percent plaque volume were measured.

RESULTS

The LAP volume, total plaque volume, and percent plaque volume showed significant regression among intensive-statin compared with no-statin group (annualized changes: -7.1 ± 13.1 vs 0.9 ± 12.7 mm(3), P< .001; -16.4 ± 35.0 vs 12.3 ± 32.4 mm(3), P< .001; and -6.2% ± 11.8% vs 3.5% ± 12.1%, P< .001, respectively). Progression of LAP volume, total plaque volume, and percent plaque volume was retarded among moderate-statin compared with no-statin group (annualized changes: -2.8 ± 7.6 vs 0.9 ± 12.7 mm(3), P= .041; -0.1 ± 25.6 vs 12.3 ± 32.4 mm(3), P= .014; and -1.8% ± 11.2% vs 3.5% ± 12.1%, P= .006, respectively). On multivariable model predicting change in total plaque volume, higher baseline LAP volume, moderate statin therapy, and intensive statin therapy were each independent predictors of plaque regression (standardized coefficients: baseline LAP volume -0.36, P< .001; moderate statin -0.21, P= .004; intensive statin -0.36, P< .001, respectively).

CONCLUSIONS

This study suggests that statin treatment can retard progression and even induce regression of mild noncalcified coronary plaque. Patients with greater baseline LAP volume are more likely to benefit from statin therapy.

Coronary artery wall shear stress is associated with endothelial dysfunction and expansive arterial remodelling in patients with coronary artery disease

AIMS

To investigate in vivo relationships between segmental wall shear stress (WSS), endothelium-dependent vasoreactivity and arterial remodelling.

METHODS AND RESULTS

Twenty-four patients with minor angiographic coronary arterial disease (≤30% stenosis severity) underwent intracoronary (IC) salbutamol provocation during intravascular ultrasound (IVUS)-upon-Doppler guidewire imaging. Macrovascular response (change in segmental lumen volume [SLV] at baseline and following IC salbutamol), plaque burden (percent atheroma volume [PAV]), remodelling indices (RI), eccentricity indices (EI) and WSS were evaluated in 179 consecutive 5 mm coronary segments. Baseline WSS was directly related to endothelium-dependent epicardial coronary vasomotion (% change SLV, coefficient 17.2, p=0.004), and inversely related to RI (coefficient -0.23, p=0.02) and EI (coefficient -10.0, p=0.001). Baseline WSS was lower in segments displaying endothelial dysfunction (defined as any change in SLV ≤0) compared with preserved function (0.66±0.33 vs. 0.71±0.22 N/m2, p=0.046). Independent of plaque burden, segments with the lowest tertile of WSS displayed less vasodilatation, or vasoconstriction, than segments with the highest tertile of WSS. Higher plaque burden segments harbouring the lowest tertiles of WSS displayed vasoconstriction, expansive arterial remodelling and greater plaque eccentricity.

CONCLUSIONS

In patients with stable coronary syndromes and minor angiographic coronary disease, coronary segments with lower in vivo WSS values display functional and morphological features of plaque vulnerability.

Ranolazine in patients with incomplete revascularisation after percutaneous coronary intervention (RIVER-PCI): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Incomplete revascularisation is common after percutaneous coronary intervention and is associated with increased mortality and adverse cardiovascular events. We aimed to assess whether adjunctive anti-ischaemic pharmacotherapy with ranolazine would improve the prognosis of patients with incomplete revascularisation after percutaneous coronary intervention.

METHODS

We performed this multicentre, randomised, parallel-group, double-blind, placebo-controlled, event-driven trial at 245 centres in 15 countries in Europe, Israel, Russia, and the USA. Patients (aged ≥18 years) with a history of chronic angina with incomplete revascularisation after percutaneous coronary intervention (defined as one or more lesions with ≥50% diameter stenosis in a coronary artery ≥2 mm diameter) were randomly assigned (1:1), via an interactive web-based block randomisation system (block sizes of ten), to receive either twice-daily oral ranolazine 1000 mg or matching placebo. Randomisation was stratified by diabetes history (presence vs absence) and acute coronary syndrome presentation (acute coronary syndrome vs non-acute coronary syndrome). Study investigators, including all research teams, and patients were masked to treatment allocation. The primary endpoint was time to first occurrence of ischaemia-driven revascularisation or ischaemia-driven hospitalisation without revascularisation. Analysis was by intention to treat. This study is registered at ClinicalTrials.gov, number NCT01442038.

FINDINGS

Between Nov 3, 2011, and May 27, 2013, we randomly assigned 2651 patients to receive ranolazine (n=1332) or placebo (n=1319); 2604 (98%) patients comprised the full analysis set. After a median follow-up of 643 days (IQR 575-758), the composite primary endpoint occurred in 345 (26%) patients assigned to ranolazine and 364 (28%) patients assigned to placebo (hazard ratio 0·95, 95% CI 0·82-1·10; p=0·48). Incidence of ischaemia-driven revascularisation and ischaemia-driven hospitalisation did not differ significantly between groups. 189 (14%) patients in the ranolazine group and 137 (11%) patients in the placebo group discontinued study drug because of an adverse event (p=0·04).

INTERPRETATION

Ranolazine did not reduce the composite rate of ischaemia-driven revascularisation or hospitalisation without revascularisation in patients with a history of chronic angina who had incomplete revascularisation after percutaneous coronary intervention. Further studies are warranted to establish whether other treatment could be effective in improving the prognosis of high-risk patients in this population.

FUNDING

Gilead Sciences, Menarini.

Near-Infrared Spectroscopy Enhances Intravascular Ultrasound Assessment of Vulnerable Coronary Plaque: A Combined Pathological and In Vivo Study

OBJECTIVES

Pathological studies demonstrate the dual significance of plaque burden (PB) and lipid composition for mediating coronary plaque vulnerability. We evaluated relationships between intravascular ultrasound (IVUS)-derived PB and arterial remodeling with near-infrared spectroscopy (NIRS)-derived lipid content in ex vivo and in vivo human coronary arteries.

APPROACH AND RESULTS

Ex vivo coronary NIRS and IVUS imaging was performed through blood in 116 coronary arteries of 51 autopsied hearts, followed by 2-mm block sectioning (n=2070) and histological grading according to modified American Heart Association criteria. Lesions were defined as the most heavily diseased 2-mm block per imaged artery on IVUS. IVUS-derived PB and NIRS-derived lipid core burden index (LCBI) of each block and lesion were analyzed. Block-level analysis demonstrated significant trends of increasing PB and LCBI across more complex atheroma (Ptrend <0.001 for both LCBI and PB). Lesion-based analyses demonstrated the highest LCBI and remodeling index within coronary fibroatheroma (Ptrend <0.001 and 0.02 versus all plaque groups, respectively). Prediction models demonstrated similar abilities of PB, LCBI, and remodeling index for discriminating fibroatheroma (c indices: 0.675, 0.712, and 0.672, respectively). A combined PB+LCBI analysis significantly improved fibroatheroma detection accuracy (c index 0.77, P=0.028 versus PB; net-reclassification index 43%, P=0.003), whereas further adding remodeling index did not (c index 0.80, P=0.27 versus PB+LCBI). In vivo comparisons of 43 age- and sex-matched patients (to the autopsy cohort) undergoing combined NIRS-IVUS coronary imaging yielded similar associations to those demonstrated ex vivo.

CONCLUSIONS

Adding NIRS to conventional IVUS-derived PB imaging significantly improves the ability to detect more active, potentially vulnerable coronary atheroma.

Assessment and Quantitation of Stent Results by Intracoronary Optical Coherence Tomography

Optical coherence tomography evaluation of poststent results includes stent expansion as the absolute minimum stent area ratio by comparing the minimum stent area with the proximal and distal reference lumen areas or mean stent area defined as the total stent volume divided by the analyzed stent length; stent strut malapposition defined when the distance from the center of the blooming artifact and the surface of plaque is greater than the sum of stent thickness and polymer thickness; tissue protrusion through the stent struts; semiquantitative residual thrombus evaluation; and stent edge dissection.

Prognostic implications of non-culprit plaques in acute coronary syndrome: non-invasive assessment with coronary CT angiography

AIMS

Non-culprit plaques are responsible for a substantial number of future events in patients with acute coronary syndrome (ACS). In this study, we evaluated the prognostic implications of non-culprit plaques seen on coronary computed tomography angiography (CTA) in patients with ACS.

METHODS AND RESULTS

Coronary CTA was performed in 169 patients (mean 59 ± 11 years, 129 males) admitted with ACS. Data sets were assessed for the presence of obstructive non-culprit plaques (>50% luminal narrowing), segment involvement score, and quantitative measures of plaque burden, after censoring initial culprit plaques. Follow-up was performed for the occurrence of major adverse cardiovascular events (MACEs) unrelated to the initial culprit plaque; cardiac death, second ACS, or coronary revascularization after 90 days. After a median follow-up of 4.8 (IQR 2.6-6.6) years, MACE occurred in 36 (24%) patients: 6 cardiac deaths, 16 second ACS, and 14 coronary revascularizations. Dyslipidaemia (hazard ratio [HR] 3.1 [95% confidence interval 1.5-6.6]) and diabetes mellitus (HR 4.8 [2.3-10.3]) were univariable clinical predictors of MACE. Patients with remaining obstructive non-culprit plaques (HR 3.66 [1.52-8.80]) and higher plaque burden index (HR 1.22 [1.01-1.48]) had a more risk of MACE. In multivariate analysis, with diabetes, dyslipidaemia, and plaque burden index, obstructive non-culprit plaques (HR 3.76 [1.28-11.09]) remained an independent predictor of MACE.

CONCLUSION

Almost a quarter of the study population experienced a new event arising from a non-culprit plaque during a follow-up of almost 5 years. ACS patients with remaining obstructive non-culprit plaques or high plaque burden have an increased risk of future MACE.

Imaging atherosclerosis and risk of plaque rupture

Atherosclerosis imaging strategies can delineate characteristics of plaques at risk of rupture and thrombosis. Structural plaque imaging identifies high-risk plaque features, including lipid pools, thin fibrous caps, and intraplaque hemorrhage. New molecular imaging techniques complement structural imaging approaches by illuminating important features of plaque biology, with a prominent focus on detecting inflammation as a high-risk phenotype. As we unravel the molecular and structural characteristics underlying thrombosis-prone plaques, there is significant promise for eventual early identification and prediction of atherosclerotic plaque complications before they occur. Here we focus on recent imaging insights into high-risk arterial plaques, the etiologic agent of acute myocardial infarction, stroke, and sudden cardiac death.

Use of ranolazine in patients with incomplete revascularization after percutaneous coronary intervention: design and rationale of the Ranolazine for Incomplete Vessel Revascularization Post-Percutaneous Coronary Intervention (RIVER-PCI) trial

BACKGROUND

Incomplete revascularization (ICR) after percutaneous coronary intervention (PCI) is common and is associated with increased rates of rehospitalization, revascularization, and mortality. Adjunctive pharmacotherapy with ranolazine, an inhibitor of the late sodium current with anti-ischemic properties, may be effective in reducing recurrent events after PCI in patients with ICR.

TRIAL DESIGN

RIVER-PCI is a phase 3, randomized, double-blind, placebo-controlled, international event-driven clinical trial evaluating the efficacy of ranolazine in patients with a history of chronic angina and ICR after PCI. Approximately 2,600 participants with ICR post-PCI will be randomized in a 1:1 ratio to ranolazine or matched placebo within 14 days of an index PCI. The primary end point of the trial is time to the first occurrence of ischemia-driven revascularization or ischemia-driven hospitalization without revascularization. Participants will be followed up for a minimum of 1 year and until at least 720 confirmed primary end point events have occurred. Secondary end points include sudden cardiac death, cardiovascular death, myocardial infarction, and measures of quality of life and cost-effectiveness. The evaluation of long-term safety will include all-cause mortality, stroke, transient ischemic attack, and hospitalization for heart failure. Enrollment commenced in November 2011 and was completed in summer 2013.

CONCLUSIONS

RIVER-PCI is a novel, large-scale, international, randomized, double-blind, placebo-controlled clinical trial evaluating the role of ranolazine in the long-term medical management of patients with ICR post-PCI.

Coronary Endothelium-Dependent Vasoreactivity and Atheroma Volume in Subjects With Stable, Minimal Angiographic Disease Versus Non–ST-Segment–Elevation Myocardial Infarction

Background—

Epicardial plaque burden and endothelial function are recognized predictors of coronary events. We aimed to investigate mechanistic relationships between atheroma volume and endothelial function in patients with non–ST-segment–elevation myocardial infarction (NSTEMI) using intravascular ultrasound.

Methods and Results—

In coronary vessels of patients with near-normal or minimal angiographic disease (n=23) and NSTEMI (n=24), intravascular ultrasound-derived measures (percent atheroma volume), arterial remodeling index, and segmental lumen volumes were performed in contiguous 5-mm epicardial segments. Repeat intravascular ultrasound imaging was performed after consecutive 5-minute intracoronary infusions (vehicle solution, 0.30 μg/min and 0.60 μg/min intracoronary salbutamol) to measure changes in segmental lumen volume (endothelium-dependent function). Male sex, diabetes mellitus, smoking, higher triglycerides, and lower high-density lipoprotein cholesterol were more prevalent in the NSTEMI group. Patients with NSTEMI demonstrated greater segmental percent atheroma volume (40.4±12 versus 27.5±14%, P<0.001), remodeling index (1.2 [1.0–1.5] versus 1.0 [0.9–1.0], P<0.001), and displayed less endothelium-dependent vasomotion (% change segmental lumen volume: 2.1±0.89 versus 5.1±0.89%, P=0.02) compared to patients with minimal angiographic disease. No significant difference in endothelial function between both groups was observed when controlling for plaque burden. Multivariate analysis for change in segmental lumen volume identified percent atheroma volume (β=−0.18, P=0.0004), high-sensitivity C-reactive protein >2 mg/L (β=−3.1, P=0.03), diabetes mellitus (β=−6.9, P<0.0001), low-density lipoprotein cholesterol levels (β=−0.04, P=0.01), and smoking (β=–3.2, P=0.01) as independent associates.

Conclusions—

Although coronary endothelial vasoreactivity is blunted in the setting of NSTEMI, this is a reflection of the greater volume of atherosclerosis and cardiovascular risk factors. Thus, the relationship between coronary endothelium-dependent vasomotor reactivity and atheroma volume remains constant irrespective of the nature of the clinical presentation.

Plaque composition and clinical outcomes in acute coronary syndrome patients with metabolic syndrome or diabetes

OBJECTIVES

The goal of this study was to characterize the extent and composition of coronary atherosclerosis in patients with diabetes mellitus or the metabolic syndrome (Met Syn) presenting with acute coronary syndromes (ACS).

BACKGROUND

Diabetes and Met Syn patients have increased rates of major adverse cardiac events (MACE), yet a systematic description of nonculprit lesions for these high-risk groups is incomplete.

METHODS

In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, ACS patients underwent 3-vessel quantitative coronary angiography, grayscale, and radiofrequency intravascular ultrasound after successful percutaneous coronary intervention (PCI). Subsequent MACE (cardiac death or arrest, myocardial infarction, or rehospitalization for unstable or progressive angina) were adjudicated to the originally treated culprit versus untreated nonculprit lesions in 3 patient groups: 1) diabetes; 2) Met Syn; and 3) neither. Median length of follow-up was 3.4 years.

RESULTS

Of 673 patients, 119 (17.7%) had diabetes and 239 (35.5%) had Met Syn. The cumulative 3-year MACE rate was 29.4% in patients with diabetes, 21.3% with Met Syn, and 17.4% with neither (p = 0.03). MACE adjudicated to untreated nonculprit lesions occurred in 18.7%, 11.7%, and 9.7% of patients, respectively (p = 0.06). Nonculprit lesions in diabetes and Met Syn patients were longer and had greater plaque burden, smaller lumen areas, with greater necrotic core and calcium content. Diabetes and Met Syn patients with future MACE had greater necrotic core and calcification compared with the normal cardiometabolic group.

CONCLUSIONS

In this PCI ACS population, patients with diabetes and Met Syn had higher 3-year MACE rates. Lesion length, plaque burden, necrotic core, and calcium content were significantly greater among nonculprit lesions of patients with diabetes and Met Syn, but only necrotic core and calcium were significantly greater in the nonculprit lesions of patients with a future MACE in this exploratory analysis.

Coronary plaque composition, morphology, and outcomes in patients with and without chronic kidney disease presenting with acute coronary syndromes

OBJECTIVES

This study sought to evaluate the impact of chronic kidney disease (CKD) on coronary atherosclerotic plaque composition, morphology, and outcomes in patients with acute coronary syndromes (ACS).

BACKGROUND

CKD patients presenting with ACS are at increased risk for adverse events. Whether or not this increased risk reflects differences in coronary plaque composition remains unknown.

METHODS

In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, patients presenting with ACS in whom percutaneous coronary intervention was successful underwent 3-vessel grayscale and radiofrequency intravascular ultrasound imaging. Lesions were prospectively characterized, and patients were followed for a median of 3.4 years. We conducted a patient-level and lesion-level analysis of study participants by comparing intravascular ultrasound parameters of untreated nonculprit lesions in patients with and without CKD.

RESULTS

Patients with CKD (n = 73, 11.3%) were older, more often female and diabetic compared to those without CKD (n = 573). Nonculprit lesions in patients with (n = 280) versus without (n = 2,390) CKD were more likely to have plaque burden ≥ 70% (11.8% vs. 8.5%, p = 0.05) and minimal luminal area ≤ 4.0 mm(2) (25.9% vs. 19.2%, p = 0.005). The percentage of plaque comprised of necrotic core (15.0% vs. 13.0%, p = 0.0001) and dense calcium (8.2% vs. 6.4%, p < 0.0001) was higher while fibrous tissue (57.7% vs. 59.8%, p < 0.0001) was lower in CKD versus non-CKD lesions. The 3-year composite rate of cardiac death, cardiac arrest, or myocardial infarction (15.1% vs. 3.3%, p < 0.0001) was significantly higher in patients with than in those without CKD, although there were no differences in the rates of events adjudicated to nonculprit lesions.

CONCLUSIONS

Following percutaneous coronary intervention of all culprit lesions in ACS, patients with versus without CKD have more extensive and severe atherosclerosis remaining in their coronary tree with plaque composed of greater necrotic core and less fibrous tissue. These influences resulted in nonsignificantly different rates of non-culprit lesion-related adverse events, although cardiac death, arrest, or myocardial infarction were more common in patients with CKD.