Mitsumasa Hirano

Persistent Impairment of Endothelial Vasomotor Function Has a Negative Impact on Outcome in Patients With Coronary Artery Disease

OBJECTIVES We assessed the hypothesis that changes in endothelial vasomotor function in response to optimized therapy for atherosclerotic coronary artery disease predict future cardiovascular events. BACKGROUND Although endothelial vasomotor dysfunction is a predictor of cardiovascular events, it remains unclear whether reversibility of endothelial dysfunction in response to risk factor reduction provides prognostic information. METHODS This study included 251 patients with newly diagnosed coronary artery disease and an impaired flow-mediated dilation (FMD) of the brachial artery (FMD <5.5%). Measurement of FMD was repeated after 6 months for individualized and optimized therapy to reduce risk factors according to American College of Cardiology/American Heart Association guidelines. Patients were followed up for 36 months or until 1 of the following events occurred: cardiac death, nonfatal myocardial infarction, recurrent and refractory angina pectoris requiring coronary revascularization, or ischemic stroke. RESULTS FMD was persistently impaired (<5.5%) in 104 (41%) patients after 6 months of optimized therapy, whereas it improved (FMD > or =5.5%) in the remaining 147 (59%) patients. During 36 months of follow-up, events occurred in 27 (26%) patients with persistently impaired FMD and in 15 (10%) patients with improved FMD (p < 0.01 by chi-square test). Multivariate Cox hazards analysis showed that persistent impairment of FMD was an independent predictor of events (hazard ratio: 2.9, 95% confidence interval: 1.5 to 6.2, p < 0.01). Baseline FMD before the optimized therapy to reduce risk factor had no significant prognostic information. CONCLUSIONS Persistent impairment of endothelial vasomotor function despite optimized therapy to reduce risk factors has an adverse impact on outcome in coronary artery disease patients.

Rapid Stabilization of Vulnerable Carotid Plaque Within 1 Month of Pitavastatin Treatment in Patients With Acute Coronary Syndrome

We determined time course of stabilization of echolucent carotid plaques by statin therapy in patients with acute coronary syndrome (ACS). Treatment with 4 mg/d pitavastatin (n = 33) or placebo (n = 32) was initiated within 3 days after onset of ACS in 65 patients with echolucent carotid plaque. Vulnerable carotid plaques were assessed by measuring plaque echolucency using carotid ultrasound with integrated backscatter (IBS) analysis before and 1 month after treatment in all patients. The calibrated IBS value (intima-media IBS value minus adventia IBS) of vulnerable carotid plaques favorably changed at 1 month after treatment in both groups, but the echolucency at 1 month improved more in the pitavastatin than in the placebo group (pitavastatin group: -18.7 ± 3.3 dB at pretreatment versus -12.7 ± 2.3 dB at 1 month *P < 0.001; placebo: -19.0 ± 3.5 dB versus -16.9 ± 3.2 dB, P < 0.05, *P < 0.01 versus the value at 1 month in placebo group). Levels of CRP, VEGF, and TNFα at 1 month were significantly lower in pitavastatin than placebo group. In conclusion, pitavastatin improved carotid plaque echolucency within 1 month of therapy in patients with ACS, in association with decrease in the inflammatory biomarkers related to vulnerable plaques.

High plasma levels of macrophage migration inhibitory factor are associated with adverse long-term outcome in patients with stable coronary artery disease and impaired glucose tolerance or type 2 diabetes mellitus

OBJECTIVES MIF is proatherogenic and is highly expressed in unstable atherosclerotic plaques. Circulating levels of MIF are increased in patients with impaired glucose tolerance or type 2 diabetes mellitus (IGT/T2DM). We examined whether high circulating levels of macrophage migration inhibitory factor (MIF) are related to increased risk of future coronary events in patients with coronary artery disease (CAD) and IGT/T2DM. METHODS Plasma MIF levels after overnight fast were measured by ELISA in 617 patients with stable CAD including 79 patients with IGT and 215 patients with T2DM. All patients were prospectively followed for 60 months or until occurrence of one of the coronary events: cardiac death, nonfatal myocardial infarction, unstable angina pectoris requiring coronary revascularization. RESULTS During the follow-up period, an event occurred in 77 (26%) patients with IGT/T2DM and 50 (15%) patients without IGT/T2DM. In patients with IGT/T2DM, higher MIF levels were a significant predictor of coronary events in a multivariate Cox proportional hazards analysis that included the known risk factors, C-reactive protein levels and medication as covariates (HR 3.3, 95% CI 1.6-8.3, p=0.006). The c-statistic showed that the predictive value of MIF levels was incremental over that of the conventional predictors for coronary events (area under ROC curve; 0.70 and 0.61, respectively, p=0.001). In contrast, MIF levels were not significantly related to future coronary events in patients without IGT/T2DM. CONCLUSIONS High MIF levels are an independent risk factor for future coronary events in CAD patients with IGT/T2DM.

Assessment of carotid plaque echolucency in addition to plaque size increases the predictive value of carotid ultrasound for coronary events in patients with coronary artery disease and mild carotid atherosclerosis

OBJECTIVES This study examined whether combined ultrasound assessment of plaque size and echolucency in the carotid artery had an additive effect for predicting coronary events in patients with coronary artery disease (CAD). Ultrasound assessment of either plaque size or echolucency of carotid artery provides prognostic information on coronary events. Combined assessment of plaque size and echolucency of carotid artery has the advantage of obtaining both structural and compositional information in the same artery in a single session. METHODS AND RESULTS Ultrasound assessment of carotid plaque maximum intima-media thickness (plaque-IMTmax) and echolucency with integrated backscatter analysis was performed in 413 patients with CAD and carotid plaque. All study patients were followed up prospectively for 54 months or until the occurrence of a coronary event. During the follow-up period, 49 coronary events occurred including 2 cardiac deaths, 10 non-fatal acute myocardial infarctions and 37 recurrent and refractory unstable angina. Multivariate Cox hazards analysis showed plaque-IMTmax alone (HR 2.01, 95%CI 1.30-3.10), plaque echogenicity alone (HR 0.86, 95%CI 0.80-0.91) and combination of high plaque-IMTmax and low echogenicity on categorical data (HR 2.56, 95%CI 1.39-4.74) were independent predictors of coronary events. Analysis using c-statistics showed that plaque-IMTmax and plaque echolucency in combination had a significant incremental effect on the predictive value of the conventional risk factors for coronary events. CONCLUSIONS Combined ultrasound assessment of carotid plaque size and echolucency has an additive value for prediction of coronary events. Further studies need to evaluate the clinical utility of both ultrasound measurements for risk stratification in CAD.

Predictive value of remnant lipoprotein for cardiovascular events in patients with coronary artery disease after achievement of LDL-cholesterol goals

OBJECTIVES Triglycerides-rich lipoproteins are related to residual cardiovascular risk in patients on lipid-lowering treatment who achieve low-density lipoprotein cholesterol (LDL-C) goals. This study examined the predictive value of remnant lipoprotein levels for cardiovascular events in patients with coronary artery disease (CAD) with LDL-C levels <100mg/dL on lipid-lowering therapy. METHODS Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol; RLP-C) were measured by an immunoseparation method in 560 patients with CAD who had LDL-C levels <100mg/dL on lipid-lowering therapy, including statin (58%), fibrate (13%) or diet only (29%). All the patients were followed prospectively for a period of ≤ 36 months or until occurrence of one of the following events: cardiac death, non fatal myocardial infarction, unstable angina requiring coronary revascularization, or ischemic stroke. RESULTS During a mean follow-up period of 33 months, 40 events occurred. Stepwise multivariate Cox proportional hazard analysis showed that RLP-C was a significant predictor of cardiovascular events after adjustment for known risk factors and lipid variables including triglycerides, non-high-density lipoprotein (HDL)-C, and total apolipoprotein B (HR 1.53, 95% CI 1.35-1.97, p<0.01). The c-statistics showed that addition of RLP-C had a greater incremental effect on the predictive value of conventional risk factors than addition of non-HDL-C or total apolipoprotein B. CONCLUSIONS RLP-C was superior to non-HDL-C for predicting cardiovascular events in CAD patients with LDL-C levels <100mg/dL on lipid-lowering treatment. Remnant lipoprotein may therefore be an important target for residual risk reduction after LDL-C goals on lipid lowering therapy.

Predictive value of serial assessment of endothelial function in chronic heart failure

BACKGROUND It remains undefined whether reversibility of endothelial dysfunction after optimized therapies for heart failure (HF) provides prognostic information in patients with HF. This study examined whether changes in endothelial vasomotor function after therapies for HF may predict future outcomes in patients with stable HF. METHODS This study included 245 patients with stable chronic ischemic HF and an impaired flow-mediated dilation (FMD) of the brachial artery (FMD <5.5%). Measurement of FMD was repeated after 6 months for individualized and optimized therapy for HF and atherosclerotic risk factors. Patients were followed for 36 months or until the occurrence of cardiac death or hospitalization with decompensated HF. RESULTS FMD was persistently impaired (<5.5%) in 130 (53%) patients after 6 months of the optimized therapy, whereas it improved (FMD ≥5.5%) in the remaining 115 (47%) patients. During follow-up, an event occurred in 26 (20%) patients with persistently impaired FMD and in 7 (6%) patients with improved FMD (p<0.01). Multivariate Cox hazards analysis showed that persistent impairment of FMD was an independent predictor of cardiac events (hazard ratio 3.0, 95% CI 1.3-6.9, p=0.013). Persistently impaired FMD had a significantly incremental effect on the predictability of brain natriuretic peptide levels for cardiac events. Baseline FMD before the therapy for HF and atherosclerotic risk factors had no significant prognostic information. CONCLUSIONS Persistent endothelial vasomotor dysfunction despite therapies for HF and atherosclerotic risk factors was a predictor of cardiac events in patients with chronic ischemic HF.

A comparison of the efficacy of combined ezetimibe and statin therapy with doubling of statin dose in patients with remnant lipoproteinemia on previous statin therapy.

BACKGROUND AND PURPOSE It remains undetermined whether the addition of ezetimibe to ongoing statin therapy is more effective than increasing the dose of statin for reducing remnant lipoprotein levels in patients with remnant lipoproteinemia on previous statin treatment. This study examined whether combined ezetimibe and statin therapy resulted in a greater improvement in remnant lipoprotein levels and endothelial function than with the dose of statin in patients with remnant lipoproteinemia on previous statin treatment. METHODS AND RESULTS A total of 63 patients with stable coronary artery disease and high levels of remnant-like lipoprotein particle cholesterol (RLP-C) (≥5.0 mg/dL) on statin treatment were assigned randomly to two groups and treated with either addition of ezetimibe (10mg/day, n=32) or doubling of statin dose (n=31). The lipid profiles and flow-mediated dilation (FMD) of the brachial artery were measured at enrollment and after 6 months of treatment. Statin and ezetimibe combined therapy reduced RLP-C and improved FMD to a greater extent than doubling the statin dose (% reduction in RLP-C, 48 ± 18% vs. 33 ± 24%, respectively, p=0.01; % improvement in FMD, 47 ± 48% vs. 24 ± 23%, respectively, p=0.02). CONCLUSIONS The addition of ezetimibe to ongoing statin treatment reduced RLP-C levels and improved endothelial dysfunction to a greater extent than doubling the statin dose in patients with high RLP-C levels on previous statin treatment. The present results are preliminary and should be confirmed by further studies on a larger number of study patients.

Short-term progression of maximum intima-media thickness of carotid plaque is associated with future coronary events in patients with coronary artery disease.

OBJECTIVE This study examined whether changes in maximum intima-media thickness of carotid plaque (plaque-IMTmax) over 6 months predict future coronary events in patients with carotid plaque and coronary artery disease (CAD). METHODS This study included 240 patients with CAD who had a carotid plaque (IMT ≥ 1.1mm) at entry. A carotid ultrasound examination was performed at entry (1st test) and after 6 months (2nd test). The carotid plaque with the greatest axial thickness at the 1st test was selected as the target plaque for monitoring the change in plaque-IMTmax. After the 2nd test, patients were prospectively followed-up for 3 years or until the occurrence of one of the following coronary events: cardiac death, non-fatal myocardial infarction, or unstable angina pectoris requiring coronary revascularization. RESULTS The change in plaque-IMTmax over 6 months ranged from -0.85 to 0.97 mm (mean, -0.006 ± 0.319 mm). There were 41 events during follow-up. In a stepwise multivariate Cox proportional hazards model, the change in plaque-IMTmax was a significant predictor of coronary events after adjustment for known risk factors (HR per 0.1mm increase over 6 months, 1.21; 95%CI, 1.10-1.33, p=0.0001). Analysis of receiver operating characteristic (ROC) curves showed that the addition of the change in plaque-IMTmax to conventional risk factors resulted in a greater area under the ROC curve compared with conventional risk factors alone (0.81 and 0.70, respectively, p=0.02). CONCLUSION Short-term progression of carotid plaque-IMTmax was associated with future coronary events in patients with CAD.

Ultrasound assessment of brachial endothelial vasomotor function in addition to carotid plaque echolucency for predicting cardiovascular events in patients with coronary artery disease

BACKGROUND Single assessment of either flow-mediated vasodilatation of the brachial artery (FMD) or carotid plaque echolucency provides prognostic information for both cerebrovascular and coronary events. OBJECTIVES This study tested the hypothesis that combined assessment using carotid plaque echolucency and FMD may have an additive effect when predicting cardiovascular events in patients with coronary artery disease (CAD). METHODS Ultrasound assessment of carotid plaque echolucency with integrated backscatter (IBS) analysis (calibrated IBS=intima-media IBS value-adventitia IBS) and FMD was performed in 547 consecutive patients with CAD. All the study patients were followed up prospectively for a period of ≤ 60 months until the occurrence of one of the following cardiovascular events: cardiac death, non-fatal myocardial infarction, unstable angina requiring coronary revascularization, or ischemic stroke. RESULTS During a mean follow-up period of 52 ± 10 months, 69 cardiovascular events occurred. A multivariate Cox proportional hazard model after 1000 bootstrapped resampling demonstrated that calibrated IBS and FMD were significant, independent predictors of future cardiovascular events after adjustment for known risk factors (calibrated IBS, HR 0.88, 95% CI 0.83-0.93; FMD, HR 0.76, 95% CI 0.68-0.85). The c-statistics, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) analyses showed that the combination of calibrated IBS and FMD values had a greater incremental effect on the predictive value of known risk factors for cardiovascular events. CONCLUSIONS Combined assessment of brachial endothelial function and carotid plaque echolucency is an independent predictor of cardiovascular events and improves risk prediction when added to known risks.

Rapid improvement of carotid plaque echogenicity within 1 month of pioglitazone treatment in patients with acute coronary syndrome

OBJECTIVE This study examined whether pioglitazone, an agonist of peroxisome proliferator-activated receptor gamma, may stabilize vulnerable plaque with use of ultrasound evaluation of carotid artery plaque echolucency in patients with acute coronary syndrome (ACS) and type 2 diabetes mellitus (DM). METHODS AND RESULTS Treatment with pioglitazone (15 or 30mg/day, n=31) or placebo (n=30) was randomly assigned and initiated within 5 days after the onset of ACS in 61 patients with type 2 DM and echolucent carotid plaques. Vulnerable carotid plaques were assessed by measuring plaque echolucency using carotid ultrasound with integrated backscatter (IBS) before, at 2 weeks, and 1 month and 6 months after initiation of treatment. An increase in IBS value reflects an increase in carotid plaque echogenicity. Calibrated IBS value (intima-media IBS value minus adventitia IBS value) of echolucent carotid plaques did not change at 2 weeks but was significantly increased at 1 month after treatment in the pioglitazone group but not in the placebo group. The increase in calibrated IBS value was not significantly correlated with the effect of pioglitazone on glycemia. CONCLUSIONS Pioglitazone rapidly improved carotid plaque echolucency within 1 month of therapy initiation in patients with ACS and type 2 DM.