Providing Regional Observations To Study Predictors Of Events In The Coronary Tree Research Articles

Abstract 10038: Combined Low Endothelial Shear Stress and High Plaque Structural Stress Heterogeneity Predicts Non-Culprit Major Adverse Cardiovascular Events; Insights From the PROSPECT Study

Introduction: Low endothelial shear stress (ESS) is a pro-atherogenic stimulus associated with coronary plaque development, while high plaque structural stress (PSS) and its heterogeneity is associated with plaque destabilization. Previous studies showed that combining ESS and PSS additively predicts plaque progression, but no studies have determined their ability to predict major adverse cardiovascular events (MACE). We examined whether combining ESS and PSS improves MACE prediction in patients with acute coronary syndrome. Methods: We examined baseline ESS, ESS gradient, PSS, and PSS heterogeneity index (HI) in 22 non-culprit lesions (NCL) leading to future MACE, and 64 randomly selected control NCLs without MACE from the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study. ESS was calculated by computational fluid dynamics and PSS by finite element analysis on co-registered lesions. Results: 86 lesions (55 thin-cap and 31 thick-cap fibroatheromas) were analyzed from 67 patients. Lesions that caused future MACE showed baseline higher PSS HI (0.32 vs. 0.24, p<0.001), lower ESS (0.56 vs. 0.91 Pa, p=0.007), higher ESS gradient (3.82 vs. 1.96 Pa/mm, p=0.007), smaller minimum lumen area (MLA, 3.83 vs. 5.05 mm 2 , p=0.002), and larger plaque burden (PB, 70% vs. 59.4%, p<0.001). Independent predictors of MACE in multivariate analysis included high PSS HI (hazard ratio [HR] 3.9, 95% confidence interval [CI] 1.5-10.4, p=0.006), high ESS gradient (HR 3.4, 95% CI 1.4-8.1, p=0.007), and high PB at the MLA (HR 2.6, 95% CI 1.1-6.3, p=0.035). Combining low ESS and high PSS HI improved test specificity to 0.83 and positive predictive value (PPV) to 59.3%, while maintaining high sensitivity at 0.73 and high negative predictive value (NPV) at 89.8%. Combining low ESS, high ESS gradient, and high PSS HI further improved prognostication, predicting 80% of MACE over 3-year follow-up (p<0.001). Conclusions: Combining baseline low ESS, high ESS gradient and high PSS heterogeneity significantly improves risk stratification of NCLs over each parameter alone. Combining parameters exceeds PPV and NPV achieved by imaging alone, and may identify lesions suitable for preemptive intervention strategies to avert future MACE.

Heterogeneous plaque geometry is associated with major adverse cardiovascular events

Abstract Objectives To determine whether coronary artery plaque-lumen geometry predicts major adverse cardiovascular events (MACE), and incorporating geometric measures enhances risk stratification from intravascular imaging. Background Prospective studies show that only a minority of plaques with higher-risk features result in future MACE, indicating the need for more predictive markers of plaque vulnerability. Plaques show heterogeneous structures and plaque-lumen geometry, both of which can promote high plaque structural stress (PSS); however, the relationships between geometric heterogeneity and MACE or PSS are unknown. Methods We examined plaque-lumen curvature, irregularity, lumen aspect ratio (LAR), roughness, PSS and their longitudinal heterogeneity (Figure 1A) in 35 non-culprit lesions (NCL) associated with MACE and 66 propensity-matched no-MACE NCL from the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study. Causes of heterogeneous geometry and PSS were examined using a separate group of co-registered virtual histology-intravascular ultrasound (VH-IVUS) and optical coherence tomography (OCT) images (n=53 plaques). Results Plaque geometry heterogeneity indices (HI) were increased in NCL MACE vs. no-MACE lesions across the whole plaque and peri-minimal luminal area (MLA) segments (HI curvature: p=0.002; HI irregularity: p<0.001; HI LAR: p=0.001; HI roughness: p=0.002). Peri-MLA HI roughness was an independent predictor of future MACE (hazard ratio: 3.69, p<0.001) (Figure 1B). Inclusion of HI roughness improved identification of NCLs leading to MACE in VH-defined thin-cap fibroatheromas (VH-TCFA, p=0.005), MLA ≤4mm2 (p=0.001), and plaque burden (PB) ≥70% (p<0.001) (Figure 1C–E), and further improved the ability of PSS to identify MACE NCLs in VH-TCFA (p=0.041), MLA ≤4mm2 (p=0.033), and PB ≥70% (p<0.001). HI roughness generally corresponded with HI PSS, but was also increased at sites of local calcification and multilayering. Conclusions Plaque-lumen geometric heterogeneity is increased across whole plaque and peri-MLA segments of NCLs causing MACE. Inclusion of geometric heterogeneity may improve the ability of intravascular imaging to predict MACE. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): British Heart Foundation

Heterogeneity of Plaque Structural Stress Is Increased in Plaques Leading to MACE: Insights From the PROSPECT Study

ObjectivesThis study sought to determine if plaque structural stress (PSS) and other plaque stress parameters are increased in plaques that cause future major adverse cardiovascular event(s) (MACE) and if incorporating these parameters improves predictive capability of intravascular ultrasonography (IVUS). BackgroundLess than 10% of coronary plaques identified as high-risk by intravascular imaging result in subsequent MACE. Thus, more specific measurements of plaque vulnerability are required for effective risk stratification. MethodsPropensity score matching in the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study plaque cohort resulted in 35 nonculprit lesions (NCL) associated with future MACE and 66 matched NCL that remained clinically silent. PSS was calculated by finite element analysis as the mechanical loading within the plaque structure in the periluminal region. ResultsPSS was increased in the minimal luminal area (MLA) regions of NCL MACE versus no MACE plaques for all plaques (PSS: 112.1 ± 5.5 kPa vs. 90.4 ± 3.3 kPa, respectively; p = 0.001) and virtual histology thin-cap fibroatheromas (VH-TCFAs) (PSS: 119.2 ± 6.6 kPa vs. 95.8 ± 5.0 kPa, respectively; p = 0.005). However, PSS was heterogeneous over short segments, and PSS heterogeneity index (HI) was markedly greater in NCL MACE than in no-MACE VH-TCFAs (HI: 0.43 ± 0.05 vs. 0.29 ± 0.03, respectively; p = 0.01). Inclusion of PSS in plaque assessment improved the identification of NCLs that led to MACE, including in VH-TCFAs (p = 0.03) and plaques with MLA ≤4 mm2 (p = 0.03). Incorporation of an HI further improved the ability of PSS to identify MACE NCLs in a variety of plaque subtypes including VH-TCFA (p = 0.001) and plaques with MLA ≤4 mm2 (p = 0.002). ConclusionsPSS and variations in PSS are increased in the peri-MLA regions of plaques that lead to MACE. Moreover, longitudinal heterogeneity in PSS is markedly increased in MACE plaques, especially VH-TCFAs, potentially predisposing to plaque rupture. Incorporation of PSS and heterogeneity in PSS may improve the ability of IVUS to predict MACE.

Role of Low Endothelial Shear Stress and Plaque Characteristics in the Prediction of Nonculprit Major Adverse Cardiac Events: The PROSPECT Study

ObjectivesThis study sought to determine whether low endothelial shear stress (ESS) adds independent prognostication for future major adverse cardiac events (MACE) in coronary lesions in patients with high-risk acute coronary syndrome (ACS) from the United States and Europe. BackgroundLow ESS is a proinflammatory, proatherogenic stimulus associated with coronary plaque development, progression, and destabilization in human-like animal models and in humans. Previous natural history studies including baseline ESS characterization investigated low-risk patients. MethodsIn the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, 697 patients with ACS underwent 3-vessel intracoronary imaging. Independent predictors of MACE attributable to untreated nonculprit (nc) coronary lesions during 3.4-year follow-up were large plaque burden (PB), small minimum lumen area (MLA), and thin-cap fibroatheroma (TCFA) morphology. In this analysis, baseline ESS of nc lesions leading to new MACE (nc-MACE lesions) and randomly selected control nc lesions without MACE (nc-non-MACE lesions) were calculated. A propensity score for ESS was constructed for each lesion, and the relationship between ESS and subsequent nc-MACE was examined. ResultsA total of 145 lesions were analyzed in 97 patients: 23 nc-MACE lesions (13 TCFAs, 10 thick-cap fibroatheromas [ThCFAs]), and 122 nc-non-MACE lesions (63 TCFAs, 59 ThCFAs). Low local ESS (<1.3 Pa) was strongly associated with subsequent nc-MACE compared with physiological/high ESS (≥1.3 Pa) (23 of 101 [22.8%]) versus (0 of 44 [0%]). In propensity-adjusted Cox regression, low ESS was strongly associated with MACE (hazard ratio: 4.34; 95% confidence interval: 1.89 to 10.00; p < 0.001). Categorizing plaques by anatomic risk (high risk: ≥2 high-risk characteristics PB ≥70%, MLA ≤4 mm2, or TCFA), high anatomic risk, and low ESS were prognostically synergistic: 3-year nc-MACE rates were 52.1% versus 14.4% versus 0.0% in high-anatomic risk/low-ESS, low-anatomic risk/low-ESS, and physiological/high-ESS lesions, respectively (p < 0.0001). No lesion without low ESS led to nc-MACE during follow-up, regardless of PB, MLA, or lesion phenotype at baseline. ConclusionsLocal low ESS provides incremental risk stratification of untreated coronary lesions in high-risk patients, beyond measures of PB, MLA, and morphology.

Predictors of Plaque Rupture Within Nonculprit Fibroatheromas in Patients With Acute Coronary Syndromes: The PROSPECT Study

ObjectivesThe study sought to examine the relative importance of lesion location versus vessel area and plaque burden in predicting plaque rupture within nonculprit fibroatheromas (FAs) in patients with acute coronary syndromes. BackgroundPrevious studies have demonstrated that plaque rupture is associated with larger vessel area and greater plaque burden clustering in the proximal segments of coronary arteries. MethodsIn the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study 3-vessel grayscale and radiofrequency-intravascular ultrasound was performed after successful percutaneous coronary intervention in 697 patients with acute coronary syndromes. Untreated nonculprit lesion FAs were classified as proximal (<20 mm), mid (20 to 40 mm), and distal (>40 mm) according to the distance from the ostium to the maximum necrotic core site. ResultsOverall, 74 ruptured FAs and 2,396 nonruptured FAs were identified in nonculprit vessels. The majority of FAs (73.6%) were located within 40 mm of the ostium, and the vessel area and plaque burden progressively decreased from proximal to distal FA location (both p < 0.001). In a multivariate logistic regression model, independent predictors for plaque rupture included the distance from the ostium to the maximum necrotic core site per millimeter (odds ratio [OR]: 0.86; 95% confidence interval [CI]: 0.76 to 0.98; p = 0.02), plaque burden per 10% (OR: 2.05; 95% CI: 1.63 to 2.58; p < 0.0001), vessel area per mm2 (OR: 1.14; 95% CI: 1.11 to 1.17; p < 0.0001), calcium (OR: 0.09; 95% CI: 0.05 to 0.18; p < 0.0001), and right coronary artery location (OR: 2.16; 95% CI: 1.25 to 3.27; p = 0.006). By receiver-operating characteristic analysis, vessel area correlated with plaque rupture stronger than either plaque burden (p < 0.001) or location (p < 0.001). ConclusionsLarge vessel area, plaque burden, proximal location, right coronary artery location, and lack of calcium were associated with FA plaque rupture. The present study suggests that among these variables, vessel area may be the strongest predictor of plaque rupture among non–left main coronary arteries. (PROSPECT: An Imaging Study in Patients With Unstable Atherosclerotic Lesions [PROSPECT]; NCT00180466)

Usefulness of Coronary Atheroma Burden to Predict Cardiovascular Events in Patients Presenting With Acute Coronary Syndromes (from the PROSPECT Study)

We investigated the relation between overall atheroma burden and clinical events in the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study. In PROSPECT, 660 patients (3,229 nonculprit lesions with a plaque burden ≥ 40% and complete intravascular ultrasound data) were divided into tertiles according to baseline percent atheroma volume (PAV: total plaque/vessel volume). Patients were followed for 3.4 years (median); major adverse cardiac events (MACE: death from cardiac causes, cardiac arrest, myocardial infarction, or rehospitalization because of unstable or progressive angina) were adjudicated to either culprit or nonculprit lesions. Compared with patients in low or intermediate PAV tertiles, patients in the high PAV tertile had the greatest prevalence of plaque rupture and radiofrequency thin-cap fibroatheroma (VH-TCFA) and the highest percentage of necrotic core volume; they were also more likely to have high-risk lesion characteristics: ≥ 1 lesion with minimal luminal area ≤ 4 mm(2), plaque burden >70%, and/or VH-TCFA. Three-year cumulative nonculprit lesion-related MACE was greater in the intermediate and high tertiles than in the low tertile (6.3% vs 14.7% vs 15.1%, low vs intermediate vs high tertiles, p = 0.009). On Cox multivariable analysis, insulin-dependent diabetes (hazard ratio [HR] 3.98, p = 0.002), PAV (HR 1.06, p = 0.03), and the presence of ≥1 VH-TCFA (HR 1.80, p = 0.02) were independent predictors of nonculprit MACE. In conclusion, increasing baseline overall atheroma burden was associated with more advanced, complex, and vulnerable intravascular ultrasound lesion morphology and independently predicted nonculprit lesion-related MACE in patients with acute coronary syndromes after successful culprit lesion intervention.

Usefulness of Beta2-Microglobulin as a Predictor of All-Cause and Nonculprit Lesion-Related Cardiovascular Events in Acute Coronary Syndromes (from the PROSPECT Study)

In the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study, plaque burden, plaque composition, and minimal luminal area were associated with an increased risk of adverse cardiovascular events arising from untreated atherosclerotic lesions (vulnerable plaques) in patients with acute coronary syndromes (ACS). We sought to evaluate the utility of biomarker profiling and clinical risk factors to predict 3-year all-cause and nonculprit lesion-related major adverse cardiac events (MACEs). Of 697 patients who underwent successful percutaneous coronary intervention (PCI) for ACS, an array of 28 baseline biomarkers was analyzed. Median follow-up was 3.4years. Beta2-microglobulin displayed the strongest predictive power of all variables assessed for all-cause and nonculprit lesion-related MACE. In a classification and regression tree analysis, patients with beta2-microglobulin >1.92mg/L had an estimated 28.7% 3-year incidence of all-cause MACE; C-peptide <1.32ng/ml was associated with a further increase in MACE to 51.2%. In a classification and regression tree analysis for untreated nonculprit lesion-related MACE, beta2-microglobulin >1.92mg/L identified a cohort with a 3-year rate of 18.5%, and C-peptide <2.22ng/ml was associated with a further increase to 25.5%. By multivariable analysis, beta2-microglobulin was the strongest predictor of all-cause and nonculprit MACE during follow-up. High-density lipoprotein (HDL), transferrin, and history of angina pectoris were also independent predictors of all-cause MACE, and HDL was an independent predictor of nonculprit MACE. In conclusion, in the PROSPECT study, beta2-microglobulin strongly predicted all-cause and nonculprit lesion-related MACE within 3years after PCI in ACS. C-peptide and HDL provided further risk stratification to identify angiographically mild nonculprit lesions prone to future MACE.

Relation of C-Reactive Protein Levels to Instability of Untreated Vulnerable Coronary Plaques (From the Prospect Study): Kelly CR, Weisz G, Maehara A, et al. Am J Cardiol 2014;114:376–83.

This paper was a subset analysis of the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) trial. This study investigated whether C-reactive protein (CRP) levels can be used to risk stratify patients with recognized and untreated coronary plaques.

Clinical Outcome of Nonculprit Plaque Ruptures in Patients With Acute Coronary Syndrome in the PROSPECT Study

The aim of this study was to report the frequency, patient and lesion-related characteristics, and outcomes of subclinical, nonculprit plaque ruptures in the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study. Plaque rupture and subsequent thrombosis is the most common cause of acute coronary syndrome (ACS). Secondary, subclinical, nonculprit plaque ruptures have been seen in both stable patients and patients with ACS; however, reports of the natural history of these secondary plaque ruptures are limited. After successful stenting in 697 patients with ACS, 3-vessel grayscale and intravascular ultrasound virtual histology (IVUS-VH) was performed in the proximal-mid segments of all 3 coronary arteries as part of a prospective multicenter study. Among 660 patients with complete IVUS data, 128 plaque ruptures were identified in 105 nonculprit lesions in 100 arteries from 93 patients (14.1%). Although the minimum lumen area (MLA) was similar, the plaque burden was significantly greater in nonculprit lesions with a plaque rupture compared with nonculprit lesions without a plaque rupture (66.0% [95% confidence interval: 64.5% to 67.4%] vs. 56.0% [95% confidence interval: 55.6% to 56.4%]; p < 0.0001). IVUS-VH analysis revealed that a nonculprit lesion with a plaque rupture was more often classified as a fibroatheroma than a nonculprit lesion without a plaque rupture (77.1% vs. 51.4%; p < 0.0001). Independent predictors of a plaque rupture were lesion length (per 10 mm; odds ratio: 1.30; p < 0.0001), plaque burden at the MLA site (per 10%; odds ratio: 2.56; p < 0.0001), vessel area at the MLA site (per 1 mm2; odds ratio: 1.13; p < 0.0001), and VH–thin-cap fibroatheroma (odds ratio: 1.80; p = 0.016). During 3 years of follow-up, the incidence of overall major adverse cardiac events did not differ significantly between the patients with and patients without subclinical, nonculprit plaque ruptures. Secondary, nonculprit plaque ruptures were seen in 14% of patients with ACS and were associated with a fibroatheroma phenotype with a residual necrotic core but not with adverse outcomes if patients were treated with optimal medical therapy as part of a multicenter study. (Providing Regional Observations to Study Predictors of Events in the Coronary Tree [PROSPECT]; NCT00180466)

Compensatory enlargement of the left main coronary artery

Glagov proposed that remodeling delayed development of significant coronary artery stenoses until plaque occupied, on average, 40% of arterial area (40% plaque burden). The aim of the current study was to confirm the previously proposed concept of coronary remodeling as first described by Glagov who studied postmortem left main coronary arteries (LMCAs). Using the in-vivo intravascular ultrasound data from the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study, we evaluated 552 LMCAs in 552 patients. External elastic membrane cross-sectional areas (CSAs) increased in proportion to the increase in plaque and media CSAs (r=0.61, P<0.0001), especially when the plaque burden was 20% or lower (r=0.88, P<0.0001). For more advanced atherosclerosis (>40% plaque burden), there was an inverse relationship between lumen CSA and plaque burden (r=-0.57, P<0.0001), whereas this relationship was weak in the presence of less than 40% plaque burden. The frequency of virtual histology derived thin-cap fibroatheroma increased with increasing plaque burden. In contrast, the frequency of pathological intimal thickening decreased. The previously proposed remodeling concept of Glagov was validated in vivo in the PROSPECT study patients. In addition, the present study suggested that plaque phenotype worsened with increasing LMCA plaque growth.

Impact of Positive and Negative Lesion Site Remodeling on Clinical Outcomes: Insights From PROSPECT

This study investigated coronary artery remodeling patterns associated with clinical outcomes. In the prospective, multicenter PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree: An Imaging Study in Patients With Unstable Atherosclerotic Lesions) study, reported predictors of nonculprit lesion (NCL) major adverse cardiac events (MACE) were an intravascular ultrasound (IVUS) minimal lumen area (MLA) ≤4 mm(2), a plaque burden ≥70%, and a IVUS-virtual histology (VH) thin-cap fibroatheroma (TCFA), but not lesion site remodeling. Overall, 697 consecutive patients with an acute coronary syndrome were enrolled and underwent 3-vessel gray-scale and IVUS-VH; 3,223 NCLs were identified by IVUS. The remodeling index (RI) was calculated as the external elastic membrane area at the MLA site divided by the average of the proximal and distal reference external elastic membrane areas. First, one third of the patients were randomly selected to determine RI cutoffs related to NCL MACE (development cohort). Receiver-operating characteristic analysis showed that there were 2 separate cut points that predicted NCL MACE: RI= 0.8789 and RI= 1.0046 (area under the curve= 0.663). These cut points were used to define negative remodeling as an RI <0.88, intermediate remodeling as an RI of 0.88 to 1.00, and positive remodeling as an RI >1.00. Second, we used the remaining two-thirds of patients to validate these cut points with respect to lesion morphology and clinical outcomes (validation cohort). Kaplan-Meier curve analysis in the validation cohort showed that NCL MACE occurred more frequent (and equally) in negative and positive remodeling lesions compared with intermediate remodeling lesions. In this cohort, negative remodeling lesions had the smallest MLA, positive remodeling lesions had the largest plaque burden, and VH TCFA, especially VH TCFA with multiple necrotic cores, was most common in negatively remodeling lesions. The present study showed the novel concept that positive and negative lesion site remodeling was associated with unanticipated NCL MACE in the PROSPECT study. ( An Imaging Study in Patients With Unstable Atherosclerotic Lesions [PROSPECT]; NCT00180466).

Clinical and Angiographic Characteristics of Patients Likely to Have Vulnerable Plaques: Analysis From the PROSPECT Study

This study sought to determine the clinical and angiographic variables that would identify patients with high-risk "vulnerable" coronary plaques. In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, in patients successfully treated for acute coronary syndrome (ACS), plaque composition, plaque burden, and minimal luminal area as detected by 3-vessel radiofrequency intravascular ultrasound (IVUS) imaging were associated with an increased risk of developing future events from untreated atherosclerotic lesions (vulnerable plaques). Whether baseline demographic and angiographic findings can be used to identify patients most likely to have vulnerable coronary plaques has not been examined. On the basis of 3-vessel radiofrequency IVUS imaging, patents in the PROSPECT trial were classified in 2 groups according to whether or not one or more untreated high-risk plaques were present, defined as having ≥2 high-risk features (a thin-cap fibroatheroma, plaque burden ≥70%, and/or minimal luminal area ≤4 mm(2)). The high-risk group (those with one or more high-risk lesions) had higher Framingham risk score (7.5 ± 3.4 vs. 6.9 ± 3.3; p= 0.04), more extensive coronary artery disease, and more nonculprit lesion-related cardiovascular events during the 3-year follow-up (hazard ratio: 2.63; 95% confidence interval: 1.62 to 3.66; p < 0.0001). However, demographic factors had poor discrimination in detecting high-risk patients (area under the curve 0.55), and discrimination was only slightly improved when angiographic variables were entered into the model (area under the curve 0.64). Clinical and angiographic characteristics had poor predictive accuracy in identifying patients with untreated high-risk plaques related to future adverse events. This finding highlights the potential value of comprehensive 3-vessel imaging assessment (either invasive or noninvasive) to evaluate plaque phenotype for more accurate risk stratification of patients admitted with ACS.

Non-Fibroatheroma Lesion Phenotype and Long-Term Clinical Outcomes: A Substudy Analysis From the PROSPECT Study

The purpose of this study was to determine the clinical impact of non-fibroatheroma lesion phenotype in patients presenting with an acute coronary syndrome (ACS). Although fibroatheromas (FAs) are known to be clinically unstable, the impact of non-FA lesion phenotype on clinical outcomes has not been studied. In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, patients presenting with an ACS underwent 3-vessel grayscale and virtual histology intravascular ultrasound (VH-IVUS) after successful percutaneous intervention for all culprit lesions and were followed for 3 years. Patients were divided into those who had only the non-FA phenotype (pathological intimal thickening or fibrotic and/or fibrocalcific lesions) versus those who had at least 1 nonculprit FA. Among 2,880 nonculprit lesions identified by VH-IVUS, 39.8% were non-FAs (1,042 pathological intimal thickening, 72 fibrotic, and 33 fibrocalcific). Nonculprit major adverse cardiac events (MACE) (death, myocardial infarction, or urgent rehospitalization for progressive or unstable angina) were attributed to only 7 non-FA lesions (0.7%) versus 43 FA lesions (2.7%, p < 0.001) during 3 years follow-up. Of 609 patients, 67 (11.0%) patients had only non-FA lesion phenotypes. Patients with only non-FAs tended to be younger and more often female, have fewer nonculprit lesions and less overall plaque burden and necrotic core, and fewer nonculprit lesion MACE compared with patients with at least 1 FA. In the adjusted Cox proportional hazards model, absence of a FA was a significant predictive of a lower 3-year nonculprit MACE rate (hazard ratio: 0.23; 95% confidence interval: 0.06 to 0.95). Non-FA lesions were clinically stable and were rarely associated with clinical events during 3 years of follow-up. The intermediate-term prognosis in patients presenting with ACS in whom all nonculprit lesions are non-FAs is favorable. ( An Imaging Study in Patients With Unstable Atherosclerotic Lesions; NCT00180466).

Relation Between Angiographic Lesion Severity, Vulnerable Plaque Morphology and Future Adverse Cardiac Events (from the Providing Regional Observations to Study Predictors of Events in the Coronary Tree Study)

Previous angiographic studies have suggested that the future risk for major adverse cardiovascular events (MACEs) is related to coronary stenosis severity. The aim of this study was to use the grayscale and virtual histology (VH)-intravascular ultrasound (IVUS) data from the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study to identify underlying lesion morphologic characteristics that might explain these findings. In PROSPECT, patients presenting with acute coronary syndromes in whom percutaneous coronary intervention was successful underwent 3-vessel grayscale and VH-IVUS and were followed for a median of 3.4 years for the incidence of MACEs. Overall, 3,115 nonculprit lesions detected by IVUS were divided into quartiles according to baseline angiographic diameter stenosis. From the first to fourth quartiles, there were increases in the prevalence of lesions with IVUS minimum luminal areas ≤ 4 mm(2), IVUS plaque burden ≥ 70%, and VH-IVUS thin-cap fibroatheroma (13.4%, 22.0%, 24.2%, and 30.3%, respectively, p <0.001), along with an increased frequency of plaque ruptures and greater necrotic core volumes. The incidence of lesions with plaque burden ≥ 70%, minimum luminal area ≤ 4 mm(2), and VH thin-cap fibroatheroma was highest in the fourth quartile (0%, 0.4%, 0.4%, and 2.8% in the first through fourth quartiles, respectively, p <0.001). Three-year MACE rates were also highest in the fourth quartile (0.3%, 0.7%, 1.3%, and 5.1%, respectively, p <0.001). In conclusion, increasing angiographic diameter stenosis was associated with an increased frequency of grayscale and VH-IVUS lesion morphologic features that have been associated with adverse events and that may, in part, explain why future MACEs were related to baseline lesion severity.

Relationship Between Palpography and Virtual Histology in Patients With Acute Coronary Syndromes

The purpose of this study was to correlate adverse events at long-term follow-up in patients after an acute coronary syndrome with coronary plaque characteristics derived from simultaneous evaluation of their mechanical and compositional properties using virtual histology (intravascular ultrasound virtual histology) and palpography. Fibroatheroma is the plaque morphology with the highest risk of causing adverse cardiac events. Palpography can potentially assess the local mechanical plaque properties with the possibility of identifying fibroatheroma with the highest risk of rupture. A total of 114 patients with acute coronary syndrome from the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) trial underwent a single ultrasound imaging investigation of their 3 coronary vessels with the co-registration of intravascular ultrasound virtual histology and palpography. Major adverse cardiac events (MACE) (cardiac death, cardiac arrest, myocardial infarction, or unstable or progressive angina) were collected up to a median follow-up of 3.4 years and adjudicated to originally treated culprit versus untreated nonculprit lesions. In total, 488 necrotic core-rich plaques were identified and subclassified as thin-cap fibroatheroma (n = 111), calcified thick-cap fibroatheroma (n = 213), and noncalcified thick-cap fibroatheroma (n = 164) and matched to their co-registered palpography data. A total of 16 MACE, adjudicated to untreated nonculprit lesions, were recorded at follow-up. In patients in whom MACE developed, fibroatheroma were larger (plaque area 10.0 mm(2) [range: 8.4 to 11.6 mm(2)] vs. 8.2 mm(2) [range: 7.7 to 8.8 mm(2)] (p = 0.03) compared with patients who were MACE free. By palpography, the maximum and the density strain values did not differ between the varying subtypes of fibroatheroma of patients with or without MACE during follow-up. In acute coronary syndromes, patients treated with stents and contemporary pharmacotherapy, palpography did not provide additional diagnostic information for the identification of fibroatheroma with a high risk of rupture and MACE during long-term follow-up. (Providing Regional Observations to Study Predictors of Events in the Coronary Tree [PROSPECT]: An Imaging Study in Patients With Unstable Atherosclerotic Lesions; NCT00180466).

Characteristics and Clinical Significance of Angiographically Mild Lesions in Acute Coronary Syndromes

The aim of this study was to assess whether residual nonculprit (NC) lesions, defined as visual diameter stenosis ≥ 30% after successful percutaneous coronary intervention, affect the rate of future events in patients with acute coronary syndromes. In patients with acute coronary syndromes, approximately one-half of recurrent events after percutaneous coronary intervention arise from untreated lesions. Patients enrolled in PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) were divided into 3 groups: those with no NC lesions, 1 NC lesion, or ≥ 2 NC lesions. Time to events for major adverse cardiac events was estimated up to 3 years. Among 697 patients, 13.3% had no NC lesions, 19.7% had 1 NC lesion, and 67.0% had ≥ 2 NC lesions. The median diameter stenoses of the NC lesions in the latter 2 groups were 36.7% (interquartile range: 31.0% to 43.4%) and 37.4% (interquartile range: 32.0% to 46.5%), respectively (p = 0.22). At least 1 thin-cap fibroatheroma was present in one-half the patients in each group. At 3 years, the incidence of major adverse cardiac events was 8.5%, 15.2%, and 24.3%, respectively (p = 0.0009). NC lesion-related events occurred in 0%, 5.0%, and 15.9% of patients, respectively (p < 0.0001). Of 105 NC lesion-related clinical events occurring during follow-up, 73 (69.5%) originated from angiographically evident baseline NC lesions (of which 36 had diameter stenosis >50%), while the other 32 arose from normal or near normal segments. Residual NC lesions are common after percutaneous coronary intervention for acute coronary syndromes and portend a higher rate of recurrent ischemic events within 3 years, especially when angiographically more severe. Conversely, the absence of NC lesions by angiography is highly predictive of freedom from events not related to the originally treated culprit lesion(s).

Gender and the Extent of Coronary Atherosclerosis, Plaque Composition, and Clinical Outcomes in Acute Coronary Syndromes

This study sought to assess the extent and composition of atherosclerosis contributing to acute coronary syndrome events in women compared with men. Pathological studies suggest that plaque composition and burden may differ by sex. It is unclear whether sex impacts the extent, characteristics, and potential vulnerability of coronary plaques. A total of 697 patients (24% women) with acute coronary syndromes were enrolled in the prospective, multicenter PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study. Three-vessel multimodality intracoronary imaging (quantitative coronary angiography, grayscale, and radiofrequency intravascular ultrasound [IVUS]) was performed after treatment of the culprit lesion(s). Events during a median 3.4-year follow-up were ascribed to recurrent culprit versus untreated nonculprit lesions. The authors performed a post hoc, sex-based subgroup analysis. Women were older and had more comorbid disease than men. By angiography, women had a similar number of angiographic culprit (p = 0.53) but fewer nonculprit (p = 0.05) lesions, and fewer vessels with nonculprit lesions (p = 0.048) compared with men even after multivariable adjustment (p = 0.002). By IVUS, women had fewer nonculprit lesions (p = 0.002), but similar plaque burden (PB) per lesion (55.6% vs. 55.3%; p = 0.35), and female sex was not predictive of severe (> 70%) PB (p = 0.052). Plaque rupture was less common in women (6.6% vs. 16.3%; p = 0.002) even after adjusting for comorbidities (p = 0.004), as was the total necrotic core volume (p < 0.0001). The frequency of other plaque phenotypes was similar for men and women including pathological intimal thickening, thin-cap fibroatheromas (TCFA), and thick-cap fibroatheromas. Rates of major adverse cardiovascular events attributed to culprit and nonculprit lesions at 1-, 2-, and 3-year follow-up were not significantly different between men and women, although women were rehospitalized more frequently due to culprit lesion-related angina. For men, nonculprit lesion minimal lumen area ≤ 4.0 mm(2), PB ≥70%, and TCFA predicted nonculprit MACE at 3 years, whereas for women, only TCFA and PB were predictive. The PROSPECT study validates that despite having more comorbid risk factors than men, women have less extensive coronary artery disease by both angiographic and IVUS measures, and that lesions in women compared with men have less plaque rupture, less necrotic core and calcium, similar plaque burden, and smaller lumens. TCFA may also be a stronger marker of plaque vulnerability in women than men.

Plaque Composition and Clinical Outcomes in Acute Coronary Syndrome Patients With Metabolic Syndrome or Diabetes

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). 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. 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. 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. 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.

Adverse Cardiovascular Events Arising From Atherosclerotic Lesions With and Without Angiographic Disease Progression

The aim of this study was to use angiography and grayscale and intravascular ultrasound-virtual histology to assess coronary lesions that caused events during a median follow-up period of 3.4 years. Vulnerable plaque-related events are assumed to be the result of substantial progression of insignificant lesions. In the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study, 697 patients with acute coronary syndromes underwent treatment of all culprit lesions followed by 3-vessel imaging to assess the natural history of culprit and untreated nonculprit (NC) lesions. Future adverse cardiovascular events adjudicated to NC lesions were divided into those with versus without substantial lesion progression (SLP) (≥ 20% angiographic diameter stenosis increase). NC lesion events occurred in 72 patients, 44 (61%) with and 28 (39%) without SLP. Myocardial infarctions (n = 6) occurred only in patients with SLP. Conversely, patients without SLP presented only with unstable or increasing angina requiring rehospitalization. Lesions with versus without SLP occurred later (median time to event 401 vs. 223 days, p = 0.07); were less severe at baseline (median diameter stenosis 26.4% vs. 53.8%, p < 0.0001) but more severe at the time of the event (mean diameter stenosis 73.8% vs. 56%, p < 0.0001); and had comparable baseline median plaque burden (68.7% vs. 70.1%, p = 0.17), minimum luminal area (3.7 vs. 4.0 mm(2), p = 0.60), and intravascular ultrasound-virtual histology phenotype (83.3% vs. 90.9%, p = 0.68; classified as fibroatheromas at baseline). NC lesions responsible for future cardiovascular events showed angiographic increase during 3.4 years of follow-up, whereas SLP underlay many but not all of them. NC events due to lesions with SLP were angiographically less severe and presented with a delayed time course but were otherwise indistinguishable from NC events that were not associated with SLP.

Coronary Plaque Composition, Morphology, and Outcomes in Patients With and Without Chronic Kidney Disease Presenting With Acute Coronary Syndromes

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). 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. 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. 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. 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.