Comparison of Intravascular Ultrasound Virtual Histology Parameters in Diabetes versus Non-Diabetes with Acute Coronary Syndrome

INTRODUCTION

The progression and pattern of coronary atherosclerosis in diabetes mellitus (DM) is different from non-DM, leading to a higher rate of vascular complications in DM.

OBJECTIVE

This study aims to assess and compare the high-risk plaque characteristics in the culprit artery of DM and non-DM patients with acute coronary syndrome (ACS) using virtual histology intravascular ultrasound (VH-IVUS).

METHODS

A total of 158 ACS patients were included, 63 of whom were known to have DM. IVUS analysis was done in the de novo target vessel and culprit lesion for which percutaneous coronary intervention was planned. Culprit lesions with a visual-estimate angiographic stenosis of <70% were excluded.

RESULTS

The mean age of patients was 52.4 ± 11.6 years. The study group comprised 82% men, 31% with hypertension, and 39.87% with DM. No significant difference was observed between the DM and non-DM groups in relation to quantitative IVUS parameters like lesion length, minimal lumen area, and plaque area. However, there was a significant difference in VH-IVUS parameters like higher necrotic core and dense calcium in the DM patients than in the non-DM patients (p < 0.01). The occurrence of VH-derived thin-cap fibroatheroma (VH-TCFA) in the culprit vessel was significantly higher in the DM group than in the non-DM group (25.3 vs. 5.2%; p < 0.01). Positive vessel-wall remodeling was noted in both groups without any significant difference (p = 0.74).

CONCLUSION

The DM patients had high-risk plaque composition features like a higher necrotic core, which is a marker of plaque vulnerability. Thus, aggressive medical therapy targeting vascular inflammation using high-dose statins would help in the stabilization of unstable plaque morphology and the reduction of major cardiovascular events.

Impacts of age on coronary atherosclerosis and vascular response to statin therapy

Age is a well-established risk factor for cardiovascular disease. Recent trials using intravascular ultrasound (IVUS) have shown that lipid-lowering therapy with statins halts the progression or induces the regression of coronary artery plaques. However, impacts of age on coronary atherosclerosis and vascular response to statin therapy have not been fully evaluated. The effects of 8-month statin therapy on coronary atherosclerosis were evaluated using virtual histology-IVUS. IVUS data were analyzed from 119 patients who were divided into two groups according to age: elderly patients (≥65 years, n = 72) and non-elderly patients (<65 years, n = 47). No patients were taking statins or other lipid-lowering therapies at baseline. At baseline, external elastic membrane (EEM) volume (17.27 vs. 14.95 mm(3)/mm, p = 0.02) and plaque volume (9.49 vs. 8.11 mm(3)/mm, p = 0.03) in the elderly patients were significantly greater than in the non-elderly patients. The EEM volume (-2.4 %, p = 0.007) and plaque volume (-3.1 %, p = 0.007) after 8-month of statin therapy had significantly decreased in the non-elderly patients but not in the elderly patients. A significant positive correlation was observed between age and percentage change in plaque volume (r = 0.265, p = 0.004). A multivariate regression analysis showed that age was a significant predictor of the percentage change in plaque volume during statin therapy (β = 0.223, p = 0.02). Coronary atherosclerosis was more advanced and vascular responses to statin therapy were attenuated in the elderly patients compared to the non-elderly patients.

C-reactive protein and future cardiovascular events in statin-treated patients with angina pectoris: the extended TRUTH study

AIM

The TRUTH trial demonstrated that 8-month statin therapy alters the composition of coronary artery plaque using virtual histology (VH)-intravascular ultrasound (IVUS). The extended TRUTH study was conducted to evaluate the relationship between changes in coronary atherosclerosis and mid-term clinical outcomes and identify the factors associated with cardiovascular events.

METHODS

Of 164 patients with angina pectoris who participated in the TRUTH trial, 119 subjects with analyzable IVUS data at both enrollment and the 8-month follow-up were enrolled and observed for at least two years. The primary end point was the time to first occurrence of cardiovascular composite events, including cardiovascular death, nonfatal myocardial infarction, nonfatal cerebral infarction, unstable angina and ischemic-driven revascularization, except for target lesion revascularization.

RESULTS

The frequency of reaching the primary end point was 13% (16/119), with a mean follow-up period of 41.9±9.4 months. Although plaque regression and changes in plaque composition were not associated with future cardiovascular events, the serum high-sensitivity C-reactive protein (hs-CRP) levels at the start of the extended TRUTH study were significantly higher in the event group than in the event-free group (1.43 mg/L vs. 0.58 mg/L, p=0.01). A multivariate logistic regression analysis showed that the hs-CRP level was an independent significant predictor of cardiovascular events (odds ratio: 1.69; 95% confidence interval: 1.14-2.50, p=0.01).

CONCLUSIONS

Coronary artery plaque regression and changes in plaque composition during statin therapy do not predict future cardiovascular events in patients with angina pectoris. Instead, the serum hs-CRP level can be used as a predictor of cardiovascular events.

Comparison of change in coronary atherosclerosis in patients with stable versus unstable angina pectoris receiving statin therapy (from the Treatment With Statin on Atheroma Regression Evaluated by Intravascular Ultrasound With Virtual Histology [TRUTH] study)

Although statin-induced regression in coronary atherosclerosis seems to be greater in patients with acute coronary syndrome than in those with stable coronary artery disease, no reports have examined this. The purpose of the present study was to compare the changes in coronary atherosclerosis in patients with stable versus unstable angina pectoris (AP). The effects of 8-month statin therapy on coronary atherosclerosis were evaluated using virtual histology intravascular ultrasound, and analyzable intravascular ultrasound data were obtained from 119 patients (83 patients with stable AP and 36 with unstable AP). A significant decrease in plaque volume was observed in patients with unstable AP (-2.2%, p = 0.02) but not in patients with stable AP. A significant increase in the necrotic-core component (0.30 mm(3)/mm, p = 0.009) was observed only in patients with unstable AP. Significant positive correlations were observed between the percentage of change in platelet-activating factor acetylhydrolase and the percentage of change in plaque volume (r = 0.346, p = 0.05) in patients with unstable AP. No significant correlations were observed in patients with stable AP. Multivariate regression analyses showed that a reduction in platelet-activating factor acetylhydrolase was associated with regression in coronary atherosclerosis, particularly of the fibrous component (β = 0.443, p = 0.003), in patients with unstable AP. In conclusion, regression of the coronary artery plaque volume was greater, although statin therapy did not halt the increases in plaque vulnerability, in patients with unstable AP compared to those with stable AP. A reduction in the serum platelet-activating factor acetylhydrolase level was associated with regression in coronary atherosclerosis, particularly the fibrous plaque volume, in patients with unstable AP.

Impacts of estimated glomerular filtration rate on coronary atherosclerosis and plaque composition before and during statin therapy in patients with normal to mild renal dysfunction: subanalysis of the TRUTH study

AIM

Renal dysfunction is an independent risk factor for cardiovascular events. However, little is known regarding the impacts of renal dysfunction on coronary atherosclerosis.

METHODS

The effects of 8-month statin therapy on coronary atherosclerosis were evaluated in the TRUTH study using virtual histology intravascular ultrasound in 164 patients with angina pectoris. We analyzed correlations between the estimated glomerular filtration rate (eGFR) and coronary atherosclerosis before and during statin therapy.

RESULTS

Baseline eGFR was 64.5 mL/min per 1.73 m(2) . Serum low-density lipoprotein cholesterol level decreased significantly from 132 to 85 mg/dL (-35%, P < 0.0001) after 8 months. Weak, but significant, negative correlations were observed between eGFR and external elastic membrane volume (r = -0.228, P = 0.01) and atheroma volume (r = -0.232, P = 0.01) at baseline. The eGFR was also negatively correlated with fibro-fatty volume (r = -0.254, P = 0.005) and fibrous volume (r = -0.241, P = 0.008) at baseline. Multivariate regression analyses showed that eGFR was a significant independent predictor associated with statin pre-treatment volume in fibro-fatty (β = -0.23, P = 0.01) and fibrous (β = -0.203, P = 0.02) components. Furthermore, eGFR was positively correlated with volume change in the fibro-fatty component during statin therapy (r = 0.215, P = 0.02).

CONCLUSION

Decreased eGFR is associated with expanding remodelling and a greater atheroma volume, particularly the fibro-fatty and fibrous volume before statin therapy in patients with normal to mild renal dysfunction. Reduction of fibro-fatty volume during statin therapy gradually accelerated with decreasing renal function.

Intensive-dose atorvastatin regimen halts progression of atherosclerotic plaques in new-onset unstable angina with borderline vulnerable plaque lesions

To compare the therapeutic effects of intensive versus moderate dosage of atorvastatin regimens in new-onset unstable angina with borderline lesions, 100 patients were randomized to receive either 80 mg/d or 20 mg/d atorvastatin for 9 months. Clinical symptoms, lipid profiles, and coronary stenosis (evaluated by coronary angiography and intravascular ultrasound) were compared to their corresponding baselines within each group and between the 2 groups after 9 months of treatment. The results showed that (1) when compared to their corresponding baselines, both groups exhibited improvement in clinical symptoms, a significant decrease in total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), and high-sensitivity C-reactive protein (hs-CRP; P < .01) and a significant increase in high-density lipoprotein cholesterol (HDL-C); (2) the improvement in clinical symptoms and the decrease in LDL-C and hs-CRP were significantly greater (P < .01) in the intensive-dose group than in the moderate-dose group; (3) the mean plaque volume did not progress in the intensive-dose group but increased significantly (P < .05) in the moderate-dose group. We conclude that compared to the moderate dose, the intensive-dose regimen significantly improves clinical symptoms, lowers LDL-C and hs-CRP, and halts the progression of borderline atherosclerotic plaques in patients with new-onset unstable angina.

Comparison of arterial remodeling and changes in plaque composition between patients with progression versus regression of coronary atherosclerosis during statin therapy (from the TRUTH study)

Statin therapy produces regression of coronary artery plaques and reduces the incidence of coronary artery disease. However, not all patients show regression of coronary atherosclerosis after statin therapy. The purpose of the present study was to identify differences in clinical characteristics, serum lipid profiles, arterial remodeling, and plaque composition between patients with progression and those with regression of coronary atherosclerosis during statin therapy. The effects of 8-month statin therapy on coronary atherosclerosis were evaluated in the Treatment With Statin on Atheroma Regression Evaluated by Intravascular Ultrasound With Virtual Histology (TRUTH) study using intravascular ultrasound-virtual histology. One hundred nineteen patients were divided into 2 groups according to atheroma volume increase (progressors) or decrease (regressors) during an 8-month follow-up period. Fifty-one patients (43%) were categorized as progressors and the remaining 68 (57%) as regressors. External elastic membrane volume increased, although not significantly (0.8%, p = 0.34), and luminal volume decreased significantly (-5.3%, p = 0.0003) in progressors, while external elastic membrane volume decreased significantly (-3.2%, p <0.0001) and luminal volume increased (2.2%, p = 0.13) in regressors. The fibrous component increased significantly in progressors, while this component decreased in regressors. A strong positive correlation was observed between change in atheroma volume and change in fibrous volume (r = 0.812, p <0.0001). In conclusion, coronary arteries showed negative remodeling during statin-induced plaque regression. The difference in plaque composition between patients with progression and those with regression of coronary atherosclerosis during statin therapy arose from the difference in the change in fibrous component.

Pitavastatin approved for treatment of primary hypercholesterolemia and combined dyslipidemia

Pitavastatin was first developed in Japan and is expanding the regions in which it is clinically available. A considerable number of clinical studies have been conducted and published to date on the usefulness of pitavastatin for patients with primary hypercholesterolemia or combined dyslipidemia. Pitavastatin demonstrates potent low-density lipoprotein cholesterol reduction at low doses of 1–4 mg/day. It also affects the regression of coronary plaques, as observed in intravascular ultrasound-guided percutaneous coronary intervention studies. Moreover, the persistent, long-term high-density lipoprotein cholesterol elevation observed in the populations treated with pitavastatin is worthy of further attention. The reported improvements in lipid profiles are consistent among the studies conducted in Japan, Korea, Thailand, and Europe. In light of accumulating clinical experience worldwide, pitavastatin is now expected to establish its position for preventing and treating cardiovascular disease.

Prevalence and clinical implication of metabolic syndrome in chronic heart failure

BACKGROUND

Metabolic syndrome (MetS) is a pathological condition with a clustering of metabolic components and is a well-known risk and prognostic factor for ischemic heart disease (IHD). However, the prevalence and clinical significance of MetS remain to be fully elucidated in chronic heart failure (CHF), an important clinical syndrome caused by various cardiac abnormalities.

METHODS AND RESULTS

The present nationwide, large-scale clinical study enrolled 3,603 patients with stage C/D CHF from 6 institutes in Japan. First, the prevalence of MetS in CHF patients was demonstrated to be 45% in males and 19% in females, which is more than double compared with the general population in Japan. The CHF patients with MetS were characterized by younger age, higher prevalence of current smoking and drinking, IHD, and hypertensive heart disease, whereas the prevalence of HF with preserved ejection fraction and MetS was higher in elderly female patients. Next, the contribution of the metabolic components (waist circumference, hypertension, glucose intolerance/diabetes mellitus and dyslipidemia) was found to be comparable between the ischemic and the non-ischemic CHF patients.

CONCLUSIONS

The prevalence of MetS in CHF patients is more than double compared with the general population in Japan and suggest that the metabolic components may have a substantial effect on the development of both ischemic and non-ischemic CHF.

Diabetes mellitus is a major negative determinant of coronary plaque regression during statin therapy in patients with acute coronary syndrome--serial intravascular ultrasound observations from the Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome Trial (the JAPAN-ACS Trial)

BACKGROUND

The Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome (JAPAN-ACS) trial has found that early aggressive statin therapy in patients with acute coronary syndrome (ACS) significantly reduces the plaque volume (PV) of non-culprit coronary lesions. The purpose of the present study was to evaluate clinical factors that have an impact on plaque regression using statin therapy.

METHODS AND RESULTS

Serial intravascular ultrasound observations over 8-12 months were performed in 252 ACS patients receiving pitavastatin or atorvastatin. Linear regression analysis identified the presence of diabetes mellitus (DM) and PV at baseline as inhibiting factors, and serum remnant-like particle-cholesterol level at baseline as a significant factor significantly affecting the degree of plaque regression. Significant correlation between % change of PV and low-density lipoprotein cholesterol (LDL-C) level was found in patients with DM (n=73, P<0.05, r=0.4), whereas there was no significant correlation between the 2 parameters in patients without DM (n=178).

CONCLUSIONS

The regression of coronary plaque induced by statin therapy after ACS was weaker in diabetic patients than their counterparts. Moreover, vigorous reduction of the LDL-C levels might induce a greater degree of plaque regression in ACS patients with DM.

Lipoproteins, platelets and atherothrombosis

Atherosclerosis and thrombosis associated with the rupture of vulnerable plaque are the main causes of cardiovascular events, including acute coronary syndrome. Low-density lipoprotein (LDL) plays a key role in the pathogenesis of atherothrombotic processes. LDLs modify the antithrombotic properties of the vascular endothelium and change vessel contractility by reducing the availability of endothelial nitric oxide and activating proinflammatory signaling pathways. In addition, LDLs also influence the functions and interactions of cells present in atherosclerotic lesions, whether they come from the circulation or are resident in vessel walls. In fact, LDLs entering affected vessels undergo modifications (e.g. oxidation, aggregation and glycosylation) that potentiate their atherogenic properties. Once modified, these intravascular LDLs promote the formation of foam cells derived from smooth muscle cells and macrophages, thereby increasing the vulnerability of atherosclerotic plaque. Moreover, they also increase the thrombogenicity of both plaque and blood, in which circulating tissue factor levels are raised and platelet reactivity is enhanced. This review focuses on the importance of native and modified LDL for the pathogenesis of atherothrombosis. It also discusses current studies on LDL and its effects on the actions of vascular cells and blood cells, particularly platelets, and considers novel potential therapeutic targets.

Critical appraisal of the role of pitavastatin in treating dyslipidemias and achieving lipid goals

Pitavastatin is a potent HMG-CoA reductase inhibitor and efficient hepatocyte low-density lipoprotein cholesterol (LDL-C) receptor inducer, producing robust reduction of the serum LDL-C levels, even at a low dose. Pitavastatin and its lactone form are minimally metabolized by CYP enzymes, and are therefore associated with minimal drug-drug interactions (DDIs). Pitavastatin 2 to 4 mg has potent LDL-C-reducing activity, equivalent to that of atorvastatin 10 to 20 mg; several clinical trials have revealed consistently superior high-density lipoprotein cholesterol (HDL-C) elevating activity of pitavastatin than that of atorvastatin. Pitavastatin-induced HDL-C elevation has been shown to be sustained, even incremental, in long-term clinical trials. Pitavastatin was as well-tolerated as atorvastatin or simvastatin in double-blind randomized clinical trials. Two-year long-term safety and effectiveness of pitavastain has been confirmed in a large-scale, prospective post-marketing surveillance. The safety and efficacy profile of pitavastatin is favorable for the treatment of dyslipidemia, especially in metabolic syndrome patients. In addition to control of LDL-C, adequate control of triglyceride (TG) and HDL-C, hypertension and hyperglycemia is also necessary in metabolic syndrome patients. Pitavastatin produces adequate control of LDL-C and TG, along with potent and incremental HDL-C elevation, with a low frequency of DDIs.