Apolipoprotein A-I is a selective target for myeloperoxidase-catalyzed oxidation and functional impairment in subjects with cardiovascular disease.

In recent studies we demonstrated that systemic levels of protein-bound nitrotyrosine (NO(2)Tyr) and myeloperoxidase (MPO), a protein that catalyzes generation of nitrating oxidants, serve as independent predictors of atherosclerotic risk, burden, and incident cardiac events. We now show both that apolipoprotein A-I (apoA-I), the primary protein constituent of HDL, is a selective target for MPO-catalyzed nitration and chlorination in vivo and that MPO-catalyzed oxidation of HDL and apoA-I results in selective inhibition in ABCA1-dependent cholesterol efflux from macrophages. Dramatic selective enrichment in NO(2)Tyr and chlorotyrosine (ClTyr) content within apoA-I recovered from serum and human atherosclerotic lesions is noted, and analysis of serum from sequential subjects demonstrates that the NO(2)Tyr and ClTyr contents of apoA-I are markedly higher in individuals with cardiovascular disease (CVD). Analysis of circulating HDL further reveals that higher NO(2)Tyr and ClTyr contents of the lipoprotein are each significantly associated with diminished ABCA1-dependent cholesterol efflux capacity of the lipoprotein. MPO as a likely mechanism for oxidative modification of apoA-I in vivo is apparently facilitated by MPO binding to apoA-I, as revealed by cross-immunoprecipitation studies in plasma, recovery of MPO within HDL-like particles isolated from human atheroma, and identification of a probable contact site between the apoA-I moiety of HDL and MPO. To our knowledge, the present results provide the first direct evidence for apoA-I as a selective target for MPO-catalyzed oxidative modification in human atheroma. They also suggest a potential mechanism for MPO-dependent generation of a proatherogenic dysfunctional form of HDL in vivo.

Prognostic value of myeloperoxidase in patients with chest pain.

BACKGROUND: Inflammation is linked to adverse outcomes in acute coronary syndromes. Myeloperoxidase, an abundant leukocyte enzyme, is elevated in culprit lesions that have fissured or ruptured in patients with sudden death from cardiac causes. Numerous lines of evidence suggest mechanistic links between myeloperoxidase and both inflammation and cardiovascular disease. METHODS: We assessed the value of plasma levels of myeloperoxidase as a predictor of the risk of cardiovascular events in 604 sequential patients presenting to the emergency department with chest pain. RESULTS: Initial plasma myeloperoxidase levels predicted the risk of myocardial infarction, even in patients who are negative for troponin T (<0.1 ng per milliliter) at base line (P<0.001). Myeloperoxidase levels at presentation also predicted the risk of major adverse cardiac events (myocardial infarction, the need for revascularization, or death) within 30 days and 6 months after presentation (P<0.001). In patients without evidence of myocardial necrosis (defined as those who were negative for troponin T), the base-line myeloperoxidase levels independently predicted the risk of major adverse coronary events at 30 days (unadjusted 2nd, 3rd, and 4th quartile odds ratios, 2.2 [95 percent confidence interval, 1.1 to 4.6], 4.2 [95 percent confidence interval, 2.1 to 8.4], and 4.1 [95 percent confidence interval, 2.0 to 8.4], respectively) and at 6 months. CONCLUSIONS: A single initial measurement of plasma myeloperoxidase independently predicts the early risk of myocardial infarction, as well as the risk of major adverse cardiac events in the ensuing 30-day and 6-month periods. Myeloperoxidase levels, in contrast to troponin T, creatine kinase MB isoform, and C-reactive protein levels, identified patients at risk for cardiac events in the absence of myocardial necrosis, highlighting its potential usefulness for risk stratification among patients who present with chest pain.

Intravascular ultrasound assessment of novel antiatherosclerotic therapies: rationale and design of the Acyl-CoA:Cholesterol Acyltransferase Intravascular Atherosclerosis Treatment Evaluation (ACTIVATE) Study.

BACKGROUND: Inhibiting the enzyme acyl-CoA:cholesterol acyltransferase (ACAT) has beneficial effects on foam cell formation and therefore has the potential to favorably influence the progression of coronary atherosclerosis. The aim of this study is to determine whether ACAT inhibition, when added to usual medical care, reduces atheroma progression in subjects with coronary artery disease. METHODS: Five hundred thirty-four subjects with established coronary artery disease on angiography were randomized to receive the experimental ACAT inhibitor, pactimibe, 100 mg daily or matching placebo for 18 months. The primary efficacy parameter will be the nominal change in percent atheroma volume determined by analysis of pullback intravascular ultrasound (IVUS) images of matched coronary artery segments acquired at baseline and 18-month follow-up. In addition, the effect of pactimibe on plasma lipids and inflammatory markers and the incidence of clinical cardiovascular events will also be assessed. CONCLUSION: Serial IVUS has emerged as a sensitive imaging modality to assess the impact that novel antiatherosclerotic strategies have on the arterial wall. In this study, IVUS will be used to assess whether ACAT inhibition modifies progression of atherosclerotic plaque.

Effect of very high-intensity statin therapy on regression of coronary atherosclerosis: the ASTEROID trial.

CONTEXT: Prior intravascular ultrasound (IVUS) trials have demonstrated slowing or halting of atherosclerosis progression with statin therapy but have not shown convincing evidence of regression using percent atheroma volume (PAV), the most rigorous IVUS measure of disease progression and regression. OBJECTIVE: To assess whether very intensive statin therapy could regress coronary atherosclerosis as determined by IVUS imaging. DESIGN AND SETTING: Prospective, open-label blinded end-points trial (A Study to Evaluate the Effect of Rosuvastatin on Intravascular Ultrasound-Derived Coronary Atheroma Burden [ASTEROID]) was performed at 53 community and tertiary care centers in the United States, Canada, Europe, and Australia. A motorized IVUS pullback was used to assess coronary atheroma burden at baseline and after 24 months of treatment. Each pair of baseline and follow-up IVUS assessments was analyzed in a blinded fashion. PATIENTS: Between November 2002 and October 2003, 507 patients had a baseline IVUS examination and received at least 1 dose of study drug. After 24 months, 349 patients had evaluable serial IVUS examinations. INTERVENTION: All patients received intensive statin therapy with rosuvastatin, 40 mg/d. MAIN OUTCOME MEASURES: Two primary efficacy parameters were prespecified: the change in PAV and the change in nominal atheroma volume in the 10-mm subsegment with the greatest disease severity at baseline. A secondary efficacy variable, change in normalized total atheroma volume for the entire artery, was also prespecified. RESULTS: The mean (SD) baseline low-density lipoprotein cholesterol (LDL-C) level of 130.4 (34.3) mg/dL declined to 60.8 (20.0) mg/dL, a mean reduction of 53.2% (P<.001). Mean (SD) high-density lipoprotein cholesterol (HDL-C) level at baseline was 43.1 (11.1) mg/dL, increasing to 49.0 (12.6) mg/dL, an increase of 14.7% (P<.001). The mean (SD) change in PAV for the entire vessel was -0.98% (3.15%), with a median of -0.79% (97.5% CI, -1.21% to -0.53%) (P<.001 vs baseline). The mean (SD) change in atheroma volume in the most diseased 10-mm subsegment was -6.1 (10.1) mm3, with a median of -5.6 mm3 (97.5% CI, -6.8 to -4.0 mm3) (P<.001 vs baseline). Change in total atheroma volume showed a 6.8% median reduction; with a mean (SD) reduction of -14.7 (25.7) mm3, with a median of -12.5 mm3 (95% CI, -15.1 to -10.5 mm3) (P<.001 vs baseline). Adverse events were infrequent and similar to other statin trials. CONCLUSIONS: Very high-intensity statin therapy using rosuvastatin 40 mg/d achieved an average LDL-C of 60.8 mg/dL and increased HDL-C by 14.7%, resulting in significant regression of atherosclerosis for all 3 prespecified IVUS measures of disease burden. Treatment to LDL-C levels below currently accepted guidelines, when accompanied by significant HDL-C increases, can regress atherosclerosis in coronary disease patients. Further studies are needed to determine the effect of the observed changes on clinical outcome. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00240318.

Serum myeloperoxidase levels independently predict endothelial dysfunction in humans.

BACKGROUND: In vitro and animal studies demonstrate that myeloperoxidase catalytically consumes nitric oxide as a substrate, limiting its bioavailability and function. We therefore hypothesized that circulating levels of myeloperoxidase would predict risk of endothelial dysfunction in human subjects. METHODS AND RESULTS: Serum myeloperoxidase was measured by enzyme-linked immunoassay, and brachial artery flow-mediated dilation and nitroglycerin-mediated dilation were determined by ultrasound in a hospital-based population of 298 subjects participating in an ongoing study of the clinical correlates of endothelial dysfunction (age, 51+/-16; 61% men, 51% with cardiovascular disease). A strong inverse relation between brachial artery flow-mediated dilation and increasing quartile of serum myeloperoxidase level was observed (11.0+/-6.0%, 9.4+/-5.3%, 8.6+/-5.8%, and 6.4+/-4.5% for quartiles 1 through 4, respectively; P<0.001 for trend). Using the median as a cut point to define endothelial dysfunction, increasing quartile of myeloperoxidase predicted endothelial dysfunction after adjustment for classic cardiovascular disease risk factors, C-reactive protein levels, prevalence of cardiovascular disease, and ongoing treatment with cardiovascular medications (OR, 6.4; 95% CI, 2.6 to 16; P=0.001 for highest versus lowest quartile). CONCLUSIONS: Serum myeloperoxidase levels serve as a strong and independent predictor of endothelial dysfunction in human subjects. Myeloperoxidase-mediated endothelial dysfunction may be an important mechanistic link between oxidation, inflammation, and cardiovascular disease.

Relationship between residual atheroma burden and neointimal growth in patients undergoing stenting: analysis of the atherectomy before MULTI-LINK improves lumen gain and clinical outcomes trial intravascular ultrasound substudy.

OBJECTIVES: The objective of this study was to examine the relationship between quantitative volumetric and cross-sectional measures of residual atheroma burden and neointimal growth after coronary stenting. BACKGROUND: Previous intravascular ultrasound (IVUS) studies have demonstrated a correlation between residual atheroma burden and neointimal growth after coronary stenting. However, postmortem studies contradict this finding. METHODS: The study population included 34 patients who underwent IVUS six to eight months after stent placement, including 26 patients who underwent IVUS immediately after stent placement and at six to eight months follow-up. Using manual planimetry, the lumen cross-sectional area (LA), stent cross-sectional area (SA) and external elastic membrane cross-sectional area (EEM) were measured at 1-mm intervals after the procedure and at follow-up. Percent neointimal area (NA) and atheroma area (AA) were calculated as: percent neointimal area = ([SA - LA]/SA) x 100; percent AA = ([EEM - SA]/EEM) x 100 in the entire cross section and in individual quadrants. Postinterventional atheroma volume and neointimal volume at follow-up were calculated using Simpsons's rule. RESULTS: In pooled analyses using all cross sections and cross-sectional quadrants, there was a weak correlation between percent AA and NA (r = 0.11 and 0.12, respectively). Analysis in individual patients demonstrated no significant relationship between total or quadrant measurements of percent AA and NA (p = 0.47 and 0.4, respectively). No relationship between atheroma volume postintervention and neointimal volume at follow-up was observed (r = 0.1, p = 0.62). CONCLUSIONS: This study failed to demonstrate a clinically significant relationship between quantitative volumetric and cross-sectional measures of residual atheroma burden and subsequent neointimal growth.

Risk factors for premature coronary artery disease and determinants of adverse outcomes after revascularization in patients < or =40 years old.

Smoking is an important and modifiable risk factor associated with premature atherosclerosis and the need for coronary revascularization in young adult patients < or =40 years old. Although intermediate and long-term survival is better in young adult patients after percutaneous coronary intervention, co-morbidities such as low ejection fraction, previous myocardial infarction, and previous bypass surgery are important adverse prognostic determinants.

Predictive models for short- and long-term adverse outcomes following discharge in a contemporary population with acute coronary syndromes.

Although numerous risk-prediction models exist in patients presenting with acute coronary syndromes (ACS), they are subject to important short-comings, including lack of contemporary information. Short-term models are frequently biased by in-hospital events. Accordingly, we sought to create contemporary risk-prediction models for clinical outcomes following ACS up to 1 year following discharge. Models were constructed for death at 30 days and 1 year, death/myocardial infarction (MI)/revascularization at 30 days and death/MI at 1 year in consecutive patients presenting with ACS at our institution between 2006 and 2008, and discharged alive. Logistic regression was used to model the 30 day outcomes and Cox proportional hazards were used to model the 1 year outcomes. No linearity assumptions were made for continuous variables. The final model coefficients were used to create a prediction nomogram, which was incorporated into an online risk calculator. A total of 2,681 patients were included, of which about 9.5% presented with ST-elevation MI. All-cause mortality was 2.6% at 30 days and 13% at 1 year. Demographic, past medical history, laboratory, pharmacological and angiographic parameters were identified as being predictive of adverse ischemic outcomes at 30 days and 1 year. The c-indices for these models ranged from 0.73 to 0.82. Our study thus identified risk factors that are predictive of short- and long-term ischemic and revascularization outcomes in contemporary patients with ACS, and incorporated them into an easy-to-use online calculator, with equal or better discriminatory power than currently available models.

Implantable cardioverter-defibrillator FDA safety advisories: Impact on patient mortality and morbidity.

BACKGROUND: A significant proportion of implantable cardioverter-defibrillators (ICDs) have been subject to Food and Drug Administration (FDA) advisories. The impact of device advisories on mortality or patient care is poorly understood. Although estimated risks of ICD generators under advisory are low, dependency on ICD therapies to prevent sudden death justifies the assessment of long-term mortality. OBJECTIVE: To test the association of FDA advisory status with long-term mortality. METHODS: The study was a retrospective, single-center review of clinical outcomes, including device malfunctions, in patients from implantation to either explant or death. Patients with ICDs first implanted at Cleveland Clinic between August 1996 and May 2004 who became subject to FDA advisories on ICD generators were identified. Mortality was determined by using the Social Security Death Index. RESULTS: In 1644 consecutive patients receiving first ICD implants, 704 (43%) became subject to an FDA advisory, of which 172 (10.5%) were class I and 532 (32.3%) were class II. ICDs were explanted before advisory notifications in 14.0% of class I and 10.1% of class II advisories. Among ICDs under advisory, 28 (4.0%) advisory-related and 15 non-advisory- related malfunctions were documented. Over a median follow-up of 70 months, 814 patients died. Kaplan-Meier 5-year survival rate was 65.6% overall, and 64.2, 61.1, and 69.3% in patients with no, class I, and class II advisories, respectively (P = .17). CONCLUSIONS: ICD advisories impacted 43% of the patients. Advisory-related malfunctions affected 4% within the combined advisory group. Based on a conservative management strategy, ICDs under advisory were not associated with increased mortality over a background of significant disease-related mortality.

Telomerase activity in pancreatic endocrine tumors.

OBJECTIVES: Pancreatic endocrine tumors (PETs) have variable prognoses, and predictors of survival are lacking. PETs can be difficult to distinguish histologically from aggressive pancreatic neoplasms such as acinar cell carcinoma. Telomerase is a ribonuclear protein that maintains the length of the telomere and induces cell immortality. Telomerase is present in 95% of pancreatic adenocarcinoma and is associated with aggressive tumor behavior. Our aim is to determine telomerase activity in PETs and investigate its potential role as a prognostic indicator. METHODS: Telomerase detection using the telomeric repeat amplification protocol was performed on frozen surgical archived pancreatic endocrine tissue from 30 patients with PETs identified by light microscopy (hematoxylin-eosin stain). All results were confirmed with internal controls. A patient's survival was measured from the time of surgery. Acinar cell differentiation (presence of zymogen granules) was determined by electron microscopy. Follow-up data were acquired via telephone interview, medical record review, and death certificates. RESULTS: Three of 30 PETs diagnosed by light microscopy were telomerase positive: three were considered nonfunctional, and two of these three patients had extrapancreatic disease. All three telomerase-positive cases were reclassified as either acinar cell carcinoma (two cases) or mixed acinar-endocrine cell carcinoma (one case). All three patients (mean age = 63 yr) died from tumor progression within 2 yr of surgery (mean = 1.6 yr +/- 0.5 SD). The remaining PETs were telomerase negative: 13 insulinomas, four nonfunctional, two sporadic glucagonomas, one gastrinoma, one vipoma, one carcinoidlike PET, and five PETs from three patients with multiple endocrine neoplasm syndrome type I and two patients with von Hippel-Lindau syndrome. Excluding insulinomas, 12 of 14 patients with telomerase-negative PETs had extrapancreatic disease. Nevertheless, Kaplan-Meier survival estimates for these 12 patients were significantly longer than for patients with telomerase-positive acinar cell carcinoma (92% vs 0% at 2 yr, p = 0.001, log rank test). The survival of all telomerase-negative PETs (n = 27) was significantly longer than that of the patients with telomerase-positive acinar cell carcinoma (93% vs 0% at 2 yr, p = 0.0001). CONCLUSIONS: Telomerase activity helps to identify acinar cell carcinomas that histologically resemble PETs, which accounts for the poor prognosis demonstrated in these patients. The absence of telomerase activity in most PETs may be responsible for their indolent clinical course. Telomerase may identify potentially progressive tumors, such as acinar cell carcinoma, and may be useful in selecting patients for more aggressive treatment.

Risk factors for hepatocellular carcinoma in patients with cirrhosis.

Recent research suggests an increase in the incidence of hepatocellular carcinoma (HCC) in the United States, which may be related to an upsurge in the sequelae of chronic liver disease from hepatitis C virus. In addition to factors related to the underlying etiology of liver disease, a number of host factors such as age, gender, and ethnic background may be associated with this increased risk. The aim of this study was to evaluate a number of potential risk factors for HCC in patients with cirrhosis. Patients with biopsy proven HCC were identified from our pathology and cancer registry databases. All those without histologic or clinical cirrhosis and non-HCC hepatic malignancies were excluded. Cirrhotic patients without HCC were also selected from the Cleveland Clinic unified transplant database and were designated controls. Extensive clinicodemographic data were obtained from the databases and chart reviews. When available, paraffin-embedded liver biopsy blocks were obtained for HFE gene analysis. Univariate comparisons were made with chi-square and Fisher's exact test and multivariate analysis was carried out with logistic regression. A total of 760 patients were included in this study, 244 documented cases of HCC and 516 cirrhotic controls without HCC. Patients' age (RR = 3.1 [2.6-3.8]; P < 0.0001), male gender (RR = 3.4 [2.3-5.1]; P < 0.0001), African-American ethnicity (RR = 3.1 [1.6-5.8]; P = 0.0005), and other non-Caucasian ethnicity (RR = 6.9 [3.2-14.4]; P < 0.0001) were independently associated with HCC. Restricting the analysis to HCV-related cirrhosis, the same risk factors remained independently associated with HCC: age (decade; RR = 2.3 [1.6-3.4]; P < 0.0001), male gender (RR = 2.9 [1.2-7.0]; P = 0.02), African-American ethnicity (RR = 3.1 [1.3-7.4]; P = 0.009), and other non-Caucasian ethnicity (RR = 15.8 [1.9-134]; P = 0.01). Iron studies did not reveal an increased risk for iron overload or HFE mutation. Male gender, advancing age, and non-Caucasian ethnic background are independently associated with HCC.

Determinants of the development of mitral regurgitation in pacing-induced heart failure.

The pacing-induced heart failure model provides an opportunity to assess the structural and functional determinants of mitral regurgitation (MR) in dilated cardiomyopathy. This study aimed to evaluate MR to better understand the multitude of factors contributing to its development. Heart failure was induced by rapid ventricular pacing (230 beats/min) in 40 mongrel dogs. Left ventricular (LV) size and MR were evaluated echocardiographically. LV contractility was analyzed using a conductance catheter. MR increased to mild in 12 animals (regurgitant orifice area, 0.06+/-0.05 cm(2)), moderate in 15 (0.14+/-0.07 cm(2)), and severe in 13 (0.34+/-0.16 cm(2)). The grade of MR had an inverse relationships with E(max) (the slope of the end-systolic pressure-volume relationship, p<0.01) and dE/dt (the slope of the maximum rate of change of pressure-end-diastolic volume [V(ED)] relationship, p<0.01) and positive relationships with V(ED) and end-diastolic cross-sectional areas and lengths (p<0.05) by univariate analysis. The dE/dt had an independently significant (p<0.01) relationship by multivariable logistic regression. Many factors influence the development of MR and because of its similarity to the clinical situation, this model can be used to investigate MR and heart failure, as well as new surgical therapies.

Association of nitrotyrosine levels with cardiovascular disease and modulation by statin therapy.

CONTEXT: Formation of nitric oxide-derived oxidants may serve as a mechanism linking inflammation to development of atherosclerosis. Nitrotyrosine, a specific marker for protein modification by nitric oxide-derived oxidants, is enriched in human atherosclerotic lesions and low-density lipoprotein (LDL) recovered from human atheroma. OBJECTIVES: To determine whether systemic levels of nitrotyrosine are associated with the prevalence of coronary artery disease (CAD) and are modulated by hydroxymethylglutaryl coenzyme-A reductase inhibitor (statin) therapy. DESIGN, SETTING, AND PATIENTS: A case-control and interventional study at 2 urban tertiary-care referral centers; recruitment for each was from June 1, 2001, until January 1, 2002. For the case-control study, 100 case-patients with established CAD and 108 patients with no clinically evident CAD were recruited consecutively. In the interventional study, participants aged 21 years or older with hypercholesterolemia (LDL cholesterol > or =130 mg/dL [> or =3.5 mmol/L]) underwent nutrition and exercise counseling. Those whose levels did not decrease with 6 to 8 weeks were enrolled in the study (n = 35). For 12 weeks, they received 10 mg/d of oral atorvastatin therapy. MAIN OUTCOME MEASURES: In the case-control study, the association between systemic levels of protein-bound nitrotyrosine, CAD risk, and presence of CAD. In the interventional study, the change in nitrotyrosine, lipoprotein, and C-reactive protein (CRP) levels. RESULTS: Nitrotyrosine levels were significantly higher among patients with CAD (median 9.1 micromol/mol [interquartile range, 4.8-13.8 micromol/mol] tyrosine vs 5.2 micromol/mol [interquartile range, 2.2-8.4 micromol/mol]; P<.001). Patients in the upper quartile of nitrotyrosine (29%; P<.001) had a higher odds of CAD compared with those in the lowest quartile (unadjusted odds ratio, 6.1; 95% confidence interval, 2.6-14.0; P<.001). In multivariate models adjusting for Framingham Global Risk Score and CRP, upper quartiles of nitrotyrosine remained associated with CAD (odds ratio, 4.4; 95% confidence interval, 1.8-10.6; P<.001). Statin therapy reduced nitrotyrosine levels significantly (25%; P<.02) with a magnitude similar to reductions in total cholesterol levels (25%; P<.001) and LDL particle number (29%; P<.001) yet were independent of alterations in lipoproteins and inflammatory markers like CRP. CONCLUSIONS: The findings from this preliminary study indicate that nitrotyrosine levels are associated with the presence of CAD and appear to be modulated by statin therapy. These results suggest a potential role for nitric oxide-derived oxidants as inflammatory mediators in CAD and may have implications for atherosclerosis risk assessment and monitoring of anti-inflammatory actions of statins.