Impact of insulin resistance on neointimal tissue proliferation after coronary stent implantation. Intravascular ultrasound studies

Insulin resistance and dysglycemia are associated with left ventricular remodeling after myocardial infarction in non-diabetic patients

Background

Adverse cardiac remodeling after ST-segment elevation myocardial infarction (STEMI) is a major cause for poor cardiovascular outcomes such as heart failure. The predisposing factors and underlying mechanisms remain not fully understood. This study investigates the association of insulin resistance and dysglycemia with left ventricular (LV) remodeling after STEMI in non-diabetic patients.

Methods

A total of 485 non-diabetic subjects with STEMI who underwent primary percutaneous coronary intervention were consecutively enrolled and followed up for 12 months. Relation of homeostasis model assessment-estimated insulin resistance (HOMA-IR) and glucose levels to changes in echocardiography parameters was studied.

Results

Left ventricular dilation was detected in 49.1% of subjects at 12-month follow-up after STEMI, and was more severe in subjects with impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and high HOMA-IR levels. HOMA-IR remained correlated to changes in LV dimensions after adjusting for confounding risk factors. Multivariate regression analysis demonstrated that higher HOMA-IR was independently associated with greater LV dilation after STEMI. A significant interaction term was present between HOMA-IR and IGT in the model (P = 0.001).

Conclusions

Our study reveals that insulin resistance and dysglycemia are prevalent in non-diabetic patients with STEMI and are predictors of the post-infarction LV dilation.

Trial registration Trials number, NCT02089360; registered on March 17, 2014

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0904-3) contains supplementary material, which is available to authorized users.

Comparison of clinical outcomes of two different types of paclitaxel-coated balloons for treatment of patients with coronary in-stent restenosis

Drug-coated balloon (DCB) angioplasty has been shown to be a promising option for the treatment of coronary in-stent restenosis (ISR). We compared the clinical outcomes of patients with ISR who were treated with two commonly used paclitaxel-containing DCBs, the Pantera Lux (PL) and SeQuent Please (SP). A total of 491 patients with 507 ISR lesions [PL-DCB in 127 (26%) patients and SP-DCB in 364 (74%) patients] underwent DCB angioplasty for ISR lesions. The major adverse cardiac events (MACEs), including cardiac death, target lesion-related myocardial infarction, and target lesion revascularization, were assessed. There were no significant differences in each occurrence of MACE and cardiac death: 16 MACEs (61 per 1000 person-years) in the PL-DCB group and 55 (60 per 1000 person-years) MACEs in the SP-DCB group, log-rank p = 0.895, and three cardiac deaths (11 per 1000 person-years) in the PL-DCB group and ten cardiac deaths (11 per 1000 person-years) in the SP-DCB group, log-rank p = 0.849. Diabetes mellitus under insulin treatment [hazard ratio (HR) 2.71; 95% confidence interval (CI) 1.31-5.60; p = 0.007], chronic kidney disease (HR 1.99; 95% CI 1.01-3.92; p = 0.045), early-onset ISR (HR 1.99; 95% CI 1.18-3.36; p = 0.010), and recurrent ISR (HR 1.89; 95% CI 1.08-3.32; p = 0.026) were associated with the occurrence of MACE after DCB angioplasty. There was no significant difference of MACE between PL-DCB and SP-DCB treatment in patients with ISR. Patients with insulin-treated diabetes, chronic kidney disease, early-onset ISR, and recurrent ISR were at a higher risk of MACE after DCB angioplasty.

Adiponectin and insulin resistance are related to restenosis and overall new PCI in subjects with normal glucose tolerance: the prospective AIRE Study

Background

In patients with Normal Glucose Tolerance (NGT) some causes of ischemic heart disease (IHD) were not completely investigated. The role both of metabolic milieu and adipokines in IHD progression was not fully investigated. Our aim was to assess the link between adipokines plasma levels, insulin resistance (IR) and IHD in NGT patients undergoing Percutaneous Coronary Intervention (PCI).

Methods

AIRE is a single-center prospective longitudinal observational study investigating the IHD outcome of NGT subjects who underwent coronary revascularization by PCI in a third level cardiology center at A.O. dei Colli Hospital, University of Campania “Luigi Vanvitelli”. Six hundred seventy-nine subjects hospitalized in 2015 for coronary arteriography not suffering from Acute Coronary Syndrome (ACS) in the previous 4 weeks, as well as from all conditions could affect glycemic plasma levels and IR status, were assessed for eligibility. Fifty-four patients with neither history of diabetes nor Altered Fasting Glucose (AFG)/Impaired Fasting Glucose (IGT) after Oral Glucose Tolerance Test (OGTT) were finally enrolled. Primary endpoint was the assessment of the relationship of adipokines and HOMA-IR with the occurrence of restenosis in NGT subjects. As secondary endpoint we assessed the association of the same adipokines and IR with overall ACS events after PCI in NGT subjects.

Results

The 54 NGT patients enrolled were mainly males (85%), with a median age of 60 years [IQR 58–63 years]. Only 4 patients (7.4%) experimented restenosis. Median follow-up was equal to 29.5 months [IQR 14.7–34 months]. Adiponectin levels were independently associated to restenosis (OR 0.206; 95% CI 0.053–0.796; p = 0.000). Instead HOMA-IR and adiponectin appeared independently associated both to de novo IHD (OR 9.6*10¹³; 95% CI 3.026–3.08*10²⁷; p = 0.042 and OR 0.206; 95% CI 0.053–0.796; p = 0.000, respectively) and overall new PCI (OR 1.5*10¹¹; 95% CI 2.593–8.68*10²¹; p = 0.042 and OR 0.206; 95% CI 0.053–0.796; p = 0.000, respectively). Moreover, we fixed a potential cut-off for adiponectin for risk of restenosis (≤ 8.5 µg/mL) and overall new PCI (≤ 9.5 µg/mL).

Conclusion

IR and cytokines play a role in progression of any stage of IHD also in NGT subjects. Our results in this setting of patients, though the relatively small sample size, represent a novelty. Future studies on larger populations are needed to analyze more in depth adipokines and insulin resistance role on IHD progression in non-diabetic people.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0826-0) contains supplementary material, which is available to authorized users.

Effect of Pioglitazone in Preventing In-Stent Restenosis after Percutaneous Coronary Intervention in Patients with Type 2 Diabetes: A Meta-Analysis

BACKGROUND

The benefits of pioglitazone in patients with type 2 diabetes mellitus (T2DM) after percutaneous coronary intervention (PCI) is unclear.

OBJECTIVES

To evaluate the effect of pioglitazone on prevention of in-stent restenosis (ISR) in patients with T2DM after PCI.

METHODS

All full-text published relevant studies compared the effect of pioglitazone with control group (placebo or no pioglitazone treatment) on ISR in patients with T2DM after PCI were identified by searching the databases including PubMed, EMBASE, Cochrane Library and ISI Web of Science through October 2015. The endpoints were defined as the rate of ISR, late lumen loss, in-stent neointimal volume, target lesion revascularization (TLR) and major adverse cardiac events (MACE).

RESULTS

Six studies (5 RCTs and 1 retrospective study), comprising 503 patients, were included into this meta-analysis. In the pioglitazone group, as compared with the control group, the risk ratio for ISR was 0.48 (I2 = 14.5%, P = 0.322; 95%CI 0.35 to 0.68, P<0.001), the risk ratio for TLR was 0.58 (I2 = 6.0%, P = 0.363; 95%CI 0.38 to 0.87, P = 0.009). The result showed there was no association between the use of pioglitazone and the events of MACE (I2 = 36.7%, P = 0.209; RR 0.56, 95%CI 0.30 to 1.05, P = 0.071). For the considerable heterogeneity, further analysis was not suitable for the endpoints of late lumen loss (I2 = 81.9%, P<0.001) and neointimal volume (I2 = 75.9%, P = 0.016).

CONCLUSIONS

The treatment of pioglitazone was associated with a reduction in ISR and TLR in T2DM patients suffering from PCI, except the incidence of MACE.

Impact of insulin resistance on post-procedural myocardial injury and clinical outcomes in patients who underwent elective coronary interventions with drug-eluting stents

OBJECTIVES

This study sought to evaluate the associations between homeostatic indexes of insulin resistance (HOMA-IR) and post-procedural myocardial injury and clinical outcome after a percutaneous coronary intervention (PCI) with a drug-eluting stent.

BACKGROUND

Insulin resistance increases the risk of cardiovascular events. However, the association between insulin resistance and clinical outcome after coronary intervention is unclear.

METHODS

We evaluated 516 consecutive patients who underwent elective PCI with drug-eluting stents. Blood samples were collected from venous blood after overnight fasting, and fasting plasma glucose and insulin levels were measured. HOMA-IR was calculated according to the homeostasis model assessment. Post-procedural myocardial injury was evaluated by analysis of troponin T and creatine kinase-myocardial band isozyme levels hours after PCI. Cardiac event was defined as the composite endpoint of cardiovascular death, myocardial infarction, and any revascularization.

RESULTS

With increasing tertiles of HOMA-IR, post-procedural troponin T and creatine kinase-myocardial band levels increased. In the multiple regression analysis, HOMA-IR was independently associated with troponin T elevation. During a median follow-up of 623 days, patients with the highest tertiles of HOMA-IR had the highest risk of cardiovascular events. The Cox proportional hazard models identified HOMA-IR as independently associated with worse clinical outcome after adjustment for clinical and procedural factors.

CONCLUSIONS

These results indicated the impact of insulin resistance on post-procedural myocardial injury and clinical outcome after elective PCI with drug-eluting stent deployment. Evaluation of insulin resistance may provide useful information for predicting clinical outcomes after elective PCI.

Impact of metabolic syndrome on re-stenosis development: role of drug-eluting stents

Metabolic syndrome (MetS) is defined as a cluster of numerous cardiovascular risk factors, which encompasses obesity, dyslipidaemia, insulin resistance and hypertension. Patients with MetS are more prone to developing cardiovascular events than other patients. To date, several approaches such as physical exercise, dietary control and invasive and non-invasive therapeutic interventions for dyslipidaemia, hypertension and insulin resistance have been used to manage MetS. However, there is a progressive elevation in the incidence of fatal and non-fatal cardiovascular events due to the increased prevalence of obesity and diabetes. Percutaneous coronary intervention has emerged over the last few years as an effective revascularisation strategy for those with coronary artery disease, in parallel with the development of effective anti-platelet medications and newer drug-eluting stents. In recent years, considerable research efforts have been undertaken to elucidate the pathophysiology of re-stenosis and develop strategies to prevent re-stenosis following percutaneous transluminal coronary angioplasty and stent implantation. Although the rate of stent re-stenosis and target-lesion revascularisation has been reduced, there is little information in the literature on the outcome of MetS in the pathophysiology of re-stenosis. In this review article, we summarise the recent development and progress on re-stenosis and the role of drug-eluting stents, particularly in MetS.

Different impact of diabetes mellitus on in-hospital and 1-year mortality in patients with acute myocardial infarction who underwent successful percutaneous coronary intervention: results from the Korean Acute Myocardial Infarction Registry

BACKGROUND/AIMS

The aim of this study was to evaluate the impact of diabetes mellitus (DM) on in-hospital and 1-year mortality in patients who suffered acute myocardial infarction (AMI) and underwent successful percutaneous coronary intervention (PCI).

METHODS

Among 5,074 consecutive patients from the Korea AMI Registry with successful revascularization between November 2005 and June 2007, 1,412 patients had a history of DM.

RESULTS

The DM group had a higher mean age prevalence of history of hypertension, dyslipidemia, ischemic heart disease, high Killip class, and diagnoses as non-ST elevation MI than the non-DM group. Left ventricular ejection fraction (LVEF) and creatinine clearance were lower in the DM group, which also had a significantly higher incidence of in-hospital and 1-year mortality of hospital survivors (4.6% vs. 2.8%, p = 0.002; 5.0% vs. 2.5%, p < 0.001). A multivariate analysis revealed that independent predictors of in-hospital mortality were Killip class IV or III at admission, use of angiotensin converting enzyme inhibitors or angiotensin-II receptor blockers, LVEF, creatinine clearance, and a diagnosis of ST-elevated MI but not DM. However, a multivariate Cox regression analysis showed that DM was an independent predictor of 1-year mortality (hazard ratio, 1.504; 95% confidence interval, 1.032 to 2.191).

CONCLUSIONS

DM has a higher association with 1-year mortality than in-hospital mortality in patients with AMI who underwent successful PCI. Therefore, even when patients with AMI and DM undergo successful PCI, they may require further intensive treatment and continuous attention.

The angiographic and clinical outcomes after coronary stenting in patients with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS) is regarded as a risk factor for coronary artery disease (CAD). But the influence of MetS on morbidity and mortality after stent implantation in CAD patients remains unknown.

METHODS

This article presents a meta-analysis of available data on the association between the MetS and the risk of angiographic and clinical outcomes following stent implantation.

RESULTS

MetS was associated with a significant increased risk of post-stent all-cause mortality (odd ratio (OR), 2.17, 95% CI, 1.56-3.01), in-lesion restenosis (OR, 1.35, 95% CI, 1.00-1.84) and major adverse cardiac events (MACE) (OR 1.35, 95% CI 1.13-1.61) in CAD patients. Even with drug-eluting stent (DES) implantation, significant increased risk in all-cause mortality (OR, 2.25, 95% CI, 1.61-3.15) and MACE (OR 1.42, 95% CI 1.14-1.76) were remain in patients with MetS. However, the OR of cardiovascular (CV) mortality (1.25, 95% CI 0.71-2.22), MI (1.27, 95% CI 0.87-1.85) and TLR (OR 1.21, 95% CI 0.96-1.53) was not statistically different between the patients with and without metabolic syndrome.

CONCLUSIONS

Metabolic syndrome is an important risk factor in patients with CAD following stent implantation. Although DES implantation decreased the incidence of angiographic events, further progress in adequate treatment of MetS is still required to improve the clinical outcome.

Transcriptional Control of Vascular Smooth Muscle Cell Proliferation by Peroxisome Proliferator-Activated Receptor-gamma: Therapeutic Implications for Cardiovascular Diseases

Proliferation of vascular smooth muscle cells (SMCs) is a critical process for the development of atherosclerosis and complications of procedures used to treat atherosclerotic diseases, including postangioplasty restenosis, vein graft failure, and transplant vasculopathy. Peroxisome proliferator-activated receptor (PPAR) gamma is a member of the nuclear hormone receptor superfamily and the molecular target for the thiazolidinediones (TZD), used clinically to treat insulin resistance in patients with type 2 diabetes. In addition to their efficacy to improve insulin sensitivity, TZD exert a broad spectrum of pleiotropic beneficial effects on vascular gene expression programs. In SMCs, PPARgamma is prominently upregulated during neointima formation and suppresses the proliferative response to injury of the arterial wall. Among the molecular target genes regulated by PPARgamma in SMCs are genes encoding proteins involved in the regulation of cell-cycle progression, cellular senescence, and apoptosis. This inhibition of SMC proliferation is likely to contribute to the prevention of atherosclerosis and postangioplasty restenosis observed in animal models and proof-of-concept clinical studies. This review will summarize the transcriptional target genes regulated by PPARgamma in SMCs and outline the therapeutic implications of PPARgamma activation for the treatment and prevention of atherosclerosis and its complications.

The predictive value of inflammatory activity and markers of the adipo-insular axis on restenosis in patients with type 2 diabetes

AIMS

Patients with type 2 diabetes (T2DM) have a high restenosis rate after percutaneous coronary intervention (PCI). This study investigated whether markers of inflammation and the adipo-insular axis associated with T2DM and poor metabolic control were able to predict restenosis after PCI in T2DM patients.

METHODS AND RESULTS

The predictive value of traditional and non-traditional risk markers, including IL-1β, IL-6, TNF-α, hsCRP, interferon gamma, leptin, IGF-I, insulin, proinsulin and NT-proBNP, was investigated in 82 patients with T2DM. A re-angiography 6 months after the index percutaneous coronary intervention (PCI) revealed that 43% of the patients had a restenosis. In a multiple regression analysis, the only independent predictors of restenosis were fasting glucose before the PCI and previous myocardial infarction (odds ratio [OR] 1.44, 95% confidence interval [CI] 1.07-1.92; p = 0.015 and OR 8.00, 95% CI 2.49-25.67; p ≤ 0.001, respectively). None of the other markers remained as significant predictors.

CONCLUSION

Fasting glucose prior to the PCI was an independent predictor of restenosis in patients with T2DM while analyses of a variety of markers related to inflammation and the adipo-insular axis did not add any further information.

Adipocytokines in atherothrombosis: focus on platelets and vascular smooth muscle cells

Visceral obesity is a relevant pathological condition closely associated with high risk of atherosclerotic vascular disease including myocardial infarction and stroke. The increased vascular risk is related also to peculiar dysfunction in the endocrine activity of adipose tissue responsible of vascular impairment (including endothelial dysfunction), prothrombotic tendency, and low-grade chronic inflammation. In particular, increased synthesis and release of different cytokines, including interleukins and tumor necrosis factor-α (TNF-α), and adipokines—such as leptin—have been reported as associated with future cardiovascular events. Since vascular cell dysfunction plays a major role in the atherothrombotic complications in central obesity, this paper aims at focusing, in particular, on the relationship between platelets and vascular smooth muscle cells, and the impaired secretory pattern of adipose tissue.

The Bypass Angioplasty Revascularization Investigation 2 Diabetes randomized trial of different treatment strategies in type 2 diabetes mellitus with stable ischemic heart disease: impact of treatment strategy on cardiac mortality and myocardial infarction

BACKGROUND

The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial in 2368 patients with stable ischemic heart disease assigned before randomization to percutaneous coronary intervention or coronary artery bypass grafting strata reported similar 5-year all-cause mortality rates with insulin sensitization versus insulin provision therapy and with a strategy of prompt initial coronary revascularization and intensive medical therapy or intensive medical therapy alone with revascularization reserved for clinical indication(s). In this report, we examine the predefined secondary end points of cardiac death and myocardial infarction (MI).

METHODS AND RESULTS

Outcome data were analyzed by intention to treat; the Kaplan-Meier method was used to assess 5-year event rates. Nominal P values are presented. During an average 5.3-year follow-up, there were 316 deaths (43% were attributed to cardiac causes) and 279 first MI events. Five-year cardiac mortality did not differ between revascularization plus intensive medical therapy (5.9%) and intensive medical therapy alone groups (5.7%; P=0.38) or between insulin sensitization (5.7%) and insulin provision therapy (6%; P=0.76). In the coronary artery bypass grafting stratum (n=763), MI events were significantly less frequent in revascularization plus intensive medical therapy versus intensive medical therapy alone groups (10.0% versus 17.6%; P=0.003), and the composite end points of all-cause death or MI (21.1% versus 29.2%; P=0.010) and cardiac death or MI (P=0.03) were also less frequent. Reduction in MI (P=0.001) and cardiac death/MI (P=0.002) was significant only in the insulin sensitization group.

CONCLUSIONS

In many patients with type 2 diabetes mellitus and stable ischemic coronary disease in whom angina symptoms are controlled, similar to those enrolled in the percutaneous coronary intervention stratum, intensive medical therapy alone should be the first-line strategy. In patients with more extensive coronary disease, similar to those enrolled in the coronary artery bypass grafting stratum, prompt coronary artery bypass grafting, in the absence of contraindications, intensive medical therapy, and an insulin sensitization strategy appears to be a preferred therapeutic strategy to reduce the incidence of MI.

Contribution of insulin resistance to vascular dysfunction

Insulin is a vascular hormone, able to influence vascular cell responses. In this review, we consider the insulin actions on vascular endothelium and on vascular smooth muscle cells (VSMC) both in physiological conditions and in the presence of insulin resistance. In particular, we focus the relationships between activation of insulin signalling pathways of phosphatidylinositol-3 kinase (PI3-K) and mitogen-activated protein kinase (MAPK) and the different vascular actions of insulin, with a particular attention to the insulin ability to activate the pathway nitric oxide (NO)/cyclic GMP/PKG via PI3-K, owing to the peculiar relevance of NO in vascular biology. We also discuss the insulin actions mediated by the MAPK pathway (such as endothelin-1 synthesis and secretion and VSMC proliferation and migration) and by the interactions between the two pathways, both in insulin-sensitive and in insulin-resistant states. Finally, we consider the influence of free fatty acids, cytokines and endothelin on vascular insulin resistance.

Hyperinsulinemia and impaired leptin-adiponectin ratio associate with endothelial nitric oxide synthase polymorphisms in subjects with in-stent restenosis

Little is known about the association of endothelial nitric oxide synthase (NOS3) gene polymorphisms and the presence of insulin resistance and the early evolution of atherosclerosis in nondiabetic subjects with cardiovascular disease (CAD) and stent implantation. The present study was performed in an attempt to better understand whether metabolic, endothelial, and angiographic findings characteristic of subjects with cardiovascular disease and in-stent restenosis are related to NOS3 variants. This is a case-control study performed from 2002 to 2006. All subjects admitted to the study were recruited in the Nord-Centre of Italy, most from Milan and its surrounding towns. Measures of glucose tolerance, insulin sensitivity, markers of endothelial dysfunction, forearm vasodilation, and adipokine levels were determined and associated to the frequency of two single-nucleotide polymorphisms of NOS3, i.e., Glu298Asp (rs1799983, G/T) and rs753482 (intron 18 A/C). A total of 747 subjects, not known to have diabetes, were evaluated: 333 subjects had asymptomatic CAD, 106 subjects had unstable angina and were evaluated for in-stent restenosis 6 mo after stent placement, and 308 were control subjects. The presence of TT and CC minor alleles was significantly greater in case groups compared with control subjects. At phenotypic level, subjects with the polymorphisms were characterized by hyperinsulinemia and reduced reactive hyperemia, whereas increased leptin and decreased adiponectin levels were present in subjects with restenosis in the presence of reduced minimal lumen diameter and length of stenosis almost doubled. Hyperinsulinemia, endothelial dysfunction, and a more atherogenic profile seem to be peculiar features of subjects with asymptomatic CAD and restenosis carrying NOS3 gene variants.

Metabolic syndrome does not increase angiographic restenosis rates after drug-eluting stent implantation

Metabolic syndrome (MS) is associated with an increased risk of coronary heart disease, stroke, and cardiovascular mortality; but its effect on patients undergoing cardiac revascularization is still unclear. Robust evidence demonstrates that diabetes mellitus and insulin resistance are among the main risk factors for restenosis in patients requiring percutaneous myocardial revascularization. The recent advent of drug-eluting stents (DESs) has significantly reduced the incidence of restenosis compared with bare-metal stents, both in nondiabetic and in diabetic patients. The aim of the study was to evaluate the effect of MS on the risk of binary restenosis in DES implant recipients. One hundred eighty-nine recipients of successful DES implants performed between January and March 2005 for stable coronary artery disease underwent 1-year clinical and angiographic follow-up. Body mass index (BMI), blood pressure, fasting blood glucose, and lipid profile were determined. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria, with the waist criterion being substituted by a BMI>or=28.8 kg/m2. Metabolic and anthropometric information for MS diagnosis was available for 148 of 189 patients; 87 of 148 patients (58%) had MS. Patients with MS had higher BMI (28.4+/-3.8 vs 26+/-2.7 kg/m2, P<.0001), systolic blood pressure (133+/-14 vs 124+/-14 mm Hg, P=.0004), and fasting glucose (113+/-37 vs 92+/-17 mg/dL, P<.0001). They also had higher serum triglycerides (154+/-94 vs 113+/-43, P=.0018) and lower high-density lipoprotein cholesterol levels (39+/-9 vs 46+/-10, P<.0001). Rates of restenosis (10.5% vs 8.1%, P=not significant [NS]), target vessel revascularization (10.5% vs 11.3%, P=NS), and major adverse cardiac events (11.6% vs 14.5%, P=NS) were not significantly different in patients with MS compared with those without MS, nor was any association found between increased end point risk and presence of MS. When patients were subdivided into 6 subgroups by the presence of 0, 1, 2, 3, 4, or 5 of the MS components, restenosis rates were not significantly different among subgroups. In conclusion, MS is not associated with higher rates of restenosis, target vessel revascularization, or major adverse cardiac events; and no additional MS feature was associated with an increased risk.

Impact of the metabolic syndrome on angiographic and clinical events after coronary intervention using bare-metal or sirolimus-eluting stents

Patients with metabolic syndrome (MS) are at increased risk for cardiovascular events. Although the number of patients with MS requiring coronary revascularization is increasing rapidly, the impact of MS on clinical events and restenosis in patients who undergo stent placement is not well defined. Seven hundred thirty-four consecutive patients with 734 de novo coronary lesions (<50 mm lesion length, reference vessel diameter <3.5 mm) were enrolled in this study. Four hundred thirty-seven patients were treated with bare-metal stents, and 297 patients were treated with sirolimus-eluting stents. Patients with bifurcation lesions, left main lesions, and ST-segment-elevation myocardial infarctions were excluded from the study. Patients were categorized into 3 groups: those with (1) diabetes mellitus (DM), (2) MS without DM, and (3) no MS and no DM. MS was defined according to American Heart Association and National Heart, Lung, and Blood Institute criteria (the presence of > or =3 of the following criteria: obesity, hypertension, hypertriglyceridemia, low high-density lipoprotein cholesterol, and increased fasting glucose). Clinical follow-up was performed for > or =1 year (mean 27.5 +/- 18.1 months). One hundred sixty-four patients (22%) had DM, 180 patients (25%) had MS without DM, and 390 patients (53%) had no MS and no DM. Baseline clinical and angiographic parameters were comparable among the 3 groups, including lesion length and reference vessel diameter. In patients treated with bare-metal stents, the rates of major adverse cardiac events (MACEs) at 12 months were 14% in patients without DM or MS, 18% in those with MS but no DM, and 33% in those with DM (p = 0.046). In patients treated with sirolimus-eluting stents, the MACE rates were 3% in patients without DM or MS, 4% in those with MS, and 13% in those with DM (p = 0.034). DM (odds ratio 2.14, 95% confidence interval 1.48 to 3.07, p <0.001) and bare-metal stent (odds ratio 2.51, 95% confidence interval 1.49 to 4.22, p <0.001) implantation were independent predictors of MACEs during follow-up, whereas MS was not predictive. Similarly, MS was not a predictor of target lesion revascularization. In conclusion, patients with MS did not have an increased risk for target lesion revascularization or a greater MACE rate compared with control patients during a 12 month follow-up period after bare-metal or drug-eluting stent placement. In contrast, DM is associated with significantly increased event rates.

Remnant-like lipoprotein particle level and insulin resistance are associated with in-stent restenosis in patients with stable angina

BACKGROUND

The aim of this study was to evaluate the independent effect of serum remnant-like lipoprotein particle level and insulin resistance on in-stent restenosis in nondiabetic patients with stable angina.

METHODS

The study included 64 nondiabetic patients with stable angina who underwent successful coronary stenting. At the time of stenting, we evaluated the patients' lipid profiles including remnant-like lipoprotein particles cholesterol, plasma glucose and insulin levels, and insulin resistance by the homeostasis model assessment.

RESULTS

There was no significant difference in total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels between two patient groups with (n=15) and without (n=49) in-stent restenosis. Plasma remnant-like lipoprotein particles cholesterol level was significantly higher in patients with restenosis than in patients without restenosis (8.2+/-7.0 mg/dl vs. 4.5+/-2.6 mg/dl, P=0.006). Although plasma glucose level was similar between the two groups, insulin level and homeostasis model assessment were significantly higher in patients with restenosis, compared with those without restenosis (11.2+/-12.4 vs. 7.1+/-2.8, P=0.039; and 2.6+/-2.9 vs. 1.7+/-0.7, P=0.040, respectively). In multivariate logistic regression analysis, plasma remnant-like lipoprotein particles cholesterol level (>4.8 mg/dl; the 75th percentile of the distribution of remnant-like lipoprotein particles cholesterol level) was the independent predictor of in-stent restenosis (odds ratio: 8.15; confidence interval: 1.02-65.16; P=0.048).

CONCLUSIONS

Our findings suggest that high serum remnant-like lipoprotein particles cholesterol level, and not insulin resistance may be an independent risk factor on in-stent restenosis in nondiabetic patients with stable angina.

Effect of thiazolidinedione therapy on restenosis after coronary stent implantation: a meta-analysis of randomized controlled trials

BACKGROUND

We sought to review the evidence from the available randomized controlled trials (RCTs) regarding the effect of thiazolidinedione therapy on in-stent restenosis after percutaneous coronary intervention.

METHODS

The studies in our meta-analysis were retrieved from search on the PubMed database and from references in relevant articles. Included studies were RCTs that provided comparative data regarding the effectiveness of 6-month pioglitazone or rosiglitazone therapy on the prevention of in-stent restenosis after coronary stent implantation as assessed by quantitative coronary angiography.

RESULTS

Five RCTs that included 235 evaluable patients who underwent coronary stent implantation and received a 6-month pioglitazone or rosiglitazone therapy were included in our meta-analysis. Restenosis rate was significantly lower in patients who received thiazolidinedione therapy in addition to standard therapy (3 RCTs, 170 patients, odds ratio 0.29, 95% CI 0.15-0.56, random effects model). Percentage diameter stenosis was significantly lower in the pioglitazone-rosiglitazone arm (3 RCTs, 170 patients, weighted difference in means 14.35, 95% CI 19.99-8.72, random effects model). Minimal lumen diameter of the target lesion was significantly higher in patients who received thiazolidinedione therapy (3 RCTs, 170 patients, weighted difference in means 0.43, 95% CI 0.21-0.65, random effects model). Patients who received thiazolidinediones were significantly less likely to undergo target lesion revascularization due to restenosis (4 RCTs, 197 patients, odds ratio 0.24, 95% CI 0.09-0.61, random effects model).

CONCLUSIONS

Our study suggests that thiazolidinedione therapy in patients undergoing coronary stent implantation may be associated with less in-stent restenosis and repeated revascularization. Decisions on clinical use of this therapy must await larger double-blind clinical trials.

Reduction of neointimal hyperplasia after coronary stenting by pioglitazone in nondiabetic patients with metabolic syndrome

BACKGROUND

This study investigates whether pioglitazone reduces neointimal hyperplasia after coronary stenting in nondiabetic patients with metabolic syndrome (MS) using intravascular ultrasound (IVUS). Pioglitazone, a novel insulin-sensitizing thiazolidinedione, has been shown to reduce neointimal hyperplasia after coronary stenting in patients with type 2 diabetes. However, the effect of pioglitazone on in-stent restenosis in nondiabetic patients with MS remains unknown.

METHODS AND RESULTS

Twenty-eight nondiabetic patients with MS after bare-metal stent implantation were randomized to 6-month treatment with or without 30 mg/d of pioglitazone (pioglitazone group [PIO] of 14 patients with 16 lesions and control group [CONT] of 14 patients with 16 lesions). At baseline and at 6-month follow-up, assessment of insulin resistance and visceral fat accumulation, quantitative coronary angiographic analysis, and IVUS measurements were performed. Pioglitazone treatment improved insulin resistance and decreased visceral fat accumulation without significant changes in plasma glucose levels, glycosylated hemoglobin A1c levels, and lipid profiles. Intimal index (intimal area/stent area) and intimal area were reduced in PIO compared with CONT (13% +/- 7% vs 21% +/- 13%, P = .033; 1.28 +/- 0.76 mm2 vs 1.90 +/- 1.16 mm2, P = .084; respectively). Binary restenosis rate was 0% in PIO versus 31% in CONT (P = .043).

CONCLUSIONS

This is the first randomized, prospective IVUS study demonstrating that pioglitazone reduces neointimal hyperplasia after coronary stenting in nondiabetic patients with MS. Our data suggest that pioglitazone treatment may represent a novel therapeutic tool to target in-stent restenosis in nondiabetic patients with MS.

Long-term effects of a PPAR-gamma agonist, pioglitazone, on neointimal hyperplasia and endothelial regrowth in insulin resistant rats

OBJECTIVE

Insulin resistance is an independent risk factor for cardiovascular disease. PPAR-gamma agonists like pioglitazone decrease insulin resistance and have been shown to reduce neointimal hyperplasia in the short-term. However long-term studies on endothelial regrowth and neointimal hyperplasia have not been done.

METHODS AND RESULTS

We used hyperinsulinemic, normoglycemic Zucker fatty rats. Rats were treated with either 10 mg/kg body wt. pioglitazone or placebo till the end of the experiment. Rats underwent carotid angioplasty at age 12-14 weeks, 1 week after treatment was begun. In one set of experiments rats were sacrificed at 6 months and neointimal hyperplasia and VEGF expression was assessed. In another set of experiments rats were sacrificed at 3 and 6 months. Endothelial regrowth was determined. The rats were all normoglycemic and hyperinsulinemic. Pioglitazone treated rats had a significantly lesser degree of neointimal hyperplasia than control rats. Treated rats also had decreased VEGF expression. Endothelial regrowth was decreased in the treated rats at 6 months.

CONCLUSION

We conclude that although pioglitazone decreases neointimal hyperplasia even at 6 months, it retards endothelial regrowth, which could predispose the denuded vessel to thrombotic events. This may be modulated by a suppression of VEGF expression.

Implications of Rosiglitazone and Pioglitazone on Cardiovascular Risk in Patients with Type 2 Diabetes Mellitus

Clinical data suggest that thiazolidinediones--specifically, rosiglitazone and pioglitazone--may improve cardiovascular risk factors through multiple mechanisms. Low insulin sensitivity has been described as an independent risk factor for coronary artery disease and cerebrovascular disease. Patients with insulin resistance often have several known risk factors, such as obesity, dyslipidemia, and hypertension. Other emerging risk factors may be prevalent in patients with insulin resistance, such as hyperinsulinemia, elevated C-reactive protein, elevated plasminogen activator inhibitor levels, and small, dense, low-density lipoproteins. The only available drug class that primarily targets insulin resistance is the thiazolidinediones. These drugs have shown efficacy in affecting surrogate markers of cardiovascular risk in patients with diabetes mellitus. Alterations in these risk factors are likely due to their effects on improving insulin sensitivity and/or glycemic control. Trials to assess whether thiazolidinediones actually reduce cardiovascular outcomes are continuing.

Obesity and clinical restenosis after coronary stent placement

BACKGROUND

Obesity has been associated with improved clinical outcomes after percutaneous coronary intervention--"obesity paradox."

METHODS

We studied 6186 patients pooled from 6 major coronary stent clinical trials. Clinical restenosis was defined as target lesion revascularization (TLR) at 1 year. Body mass index was classified according to World Health Organization criteria as underweight (< 18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), obesity class I (30-34.9 kg/m2), and obesity class II/III (> or = 35 kg/m2). Multivariable logistic regression analysis was used to evaluate the effect of obesity class on TLR.

RESULTS

Compared with normal-weight patients, there was a trend to more frequent TLR in patients of obesity class II/III (13.6% vs 10.9%, P = .08). After adjustment for previously defined predictors of TLR, other than the obesity-related intermediate states of diabetes and hypertension, obesity class II/III was associated with 1.33-fold (95% CI 1.00-1.78) higher odds of TLR. In an analysis restricted to patients without diabetes or hypertension, obesity class II/III was also associated with significantly higher odds of undergoing TLR (odd ratio [OR] 2.14, 95% CI 1.21-3.77).

CONCLUSION

After coronary stenting, the odds of undergoing TLR were higher in patients with obesity class II/III compared with normal-weight patients. The significant association of severe obesity in nondiabetic and normotensive patients suggests that other obesity-associated mechanisms such as insulin resistance and inflammation should be further explored.

Vascular neointimal formation and signaling pathway activation in response to stent injury in insulin-resistant and diabetic animals

Diabetes and insulin resistance are associated with increased disease risk and poor outcomes from cardiovascular interventions. Even drug-eluting stents exhibit reduced efficacy in patients with diabetes. We now report the first study of vascular response to stent injury in insulin-resistant and diabetic animal models. Endovascular stents were expanded in the aortae of obese insulin-resistant and type 2 diabetic Zucker rats, in streptozotocin-induced type 1 diabetic Sprague-Dawley rats, and in matched controls. Insulin-resistant rats developed thicker neointima (0.46+/-0.08 versus 0.37+/-0.06 mm2, P=0.05), with decreased lumen area (2.95+/-0.26 versus 3.29+/-0.15 mm2, P=0.03) 14 days after stenting compared with controls, but without increased vascular inflammation (ED1+ tissue macrophages). Insulin-resistant and diabetic rat vessels did exhibit markedly altered signaling pathway activation 1 and 2 weeks after stenting, with up to a 98% increase in p-ERK (anti-phospho ERK) and a 54% reduction in p-Akt (anti-phospho Akt) stained cells. Western blotting confirmed a profound effect of insulin resistance and diabetes on Akt and ERK signaling in stented segments. p-ERK/p-Akt ratio in stented segments uniquely correlated with neointimal response (R2=0.888, P=0.04) in insulin-resistant and type 1 and 2 diabetic rats, but not in lean controls. Transfemoral aortic stenting in rats provides insight into vascular responses in insulin resistance and diabetes. Shifts in ERK and Akt signaling related to insulin resistance may reflect altered tissue repair in diabetes accompanied by a shift in metabolic:proliferative balance. These findings may help explain the increased vascular morbidity in diabetes and suggest specific therapies for patients with insulin resistance and diabetes.

Insulin, C-Peptide, and Restenosis after Femoral Artery Balloon Angioplasty in Type II Diabetic and Nondiabetic Patients

PURPOSE

Endogenous and exogenous insulin is suggested to stimulate hypertrophic wound-healing responses and therefore may promote neointimal hyperplasia and restenosis after balloon angioplasty. The ratio of C-peptide to insulin reflects endogenous insulin secretion. In diabetic patients with insulin substitution, lower ratios display a higher proportion of exogenous insulin. The association and interaction of insulin and C-peptide with restenosis after percutaneous transluminal angioplasty (PTA) was investigated in type II diabetic and nondiabetic patients.

MATERIALS AND METHODS

The study group included 76 patients (median age, 68 years; interquartile range [IQR], 58-74 years; 55 men [72%]; 31 patients [41%] with type II diabetes) with intermittent claudication (n = 49; 64%) or critical limb ischemia (n = 27; 36%) who underwent primary successful femoral PTA. C-peptide and insulin levels were measured at baseline, and patients were followed to determine restenosis (> or =50%) at 12 months by color-coded duplex sonography.

RESULTS

Restenosis was found in 34 patients (45%) at 12 months. Patients with restenosis had higher insulin levels (median, 21.3 microU/mL IQR, 11.3-35.5 microU/mL) and a lower C-peptide/insulin ratio (median, 16; IQR, 10-21) compared with patients without restenosis (median insulin level, 11.6 microU/mL; IQR, 9.1-22.0 microU/mL [P = .008]; median ratio, 19 [IQR, 17-25], P = .039). In nondiabetic patients, insulin levels were significantly associated with restenosis (P = .046), whereas the ratio of C-peptide to insulin showed no association with restenosis. In patients with type II diabetes (n = 31; 41%), in contrast, the C-peptide/insulin ratio was associated with restenosis (P = .047), whereas insulin levels showed no significant association with restenosis (P = .14).

CONCLUSIONS

Insulin levels and the C-peptide/insulin ratio were associated with restenosis after femoral PTA. Exogenous and endogenous insulin may play a role in the pathogenesis of recurrent lumen loss after balloon angioplasty.

Peroxisome proliferator-activated receptor-gamma: therapeutic target for diseases beyond diabetes: quo vadis?

The discovery that the insulin-sensitising thiazolidinediones (TZDs), specific peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists, have antiproliferative, anti-inflammatory and immunomodulatory effects has led to the evaluation of their potential use in the treatment of diabetic complications and inflammatory, proliferative diseases in non-insulin-resistant, euglycaemic individuals. Apart from improving insulin resistance, plasma lipids and systemic inflammatory markers, ameliorating atherosclerosis and preventing coronary artery restenosis in diabetic subjects, currently approved TZDs have been shown to improve psoriasis and ulcerative colitis in euglycaemic human subjects. These data imply that the activation of PPAR-gamma may improve cardiovascular risk factors and cardiovascular outcomes in both insulin-resistant diabetic and non-diabetic individuals. Through their immunomodulatory and anti-inflammatory actions, TZDs and other PPAR-gamma agonists may prove to be effective in treating diseases unrelated to insulin resistance, such as autoimmune (e.g., multiple sclerosis), atopic (e.g., asthma, atopic dermatitis) and other inflammatory diseases (e.g., psoriasis, ulcerative colitis). Newer and safer selective PPAR-gamma agonists are presently under development. Furthermore, of considerable interest is the recent discovery that a unique subset of currently prescribed antihypertensive angiotensin II Type 1 receptor antagonists has selective PPAR-gamma-modulating activity. These discoveries pave the way for the development of drugs for treating chronic multigenic cardiovascular and metabolic diseases, for which therapy is presently insufficient or non-existent. The potential utility of the currently available TZDs rosiglitazone and pioglitazone and PPAR-gamma-modulating angiotensin II Type 1 receptor antagonists in treating cardiovascular, metabolic and inflammatory diseases in insulin resistant and euglycaemic states is of immense clinical potential and should be investigated.

Thiazolidinedione regulation of smooth muscle cell proliferation

Vascular smooth muscle cells (VSMCs) in the media of adult arteries are normally quiescent, proliferate at low frequency, and are arrested in the G(0)/G(1) phase of the cell cycle. Proliferation of VSMCs occurs in response to arterial injury and plays a crucial role in the atherosclerotic process and in the pathogenesis of restenosis. Patients with type 2 diabetes mellitus are at increased risk for postangioplasty restenosis, which results from excessive intimal hyperplasia. Insulin sensitizers of the thiazolidinedione (TZD) class inhibit growth of VSMCs by attenuating the activity of important cell-cycle regulators. The TZDs inhibit progression from G(1) to S phase in the cell cycle by blocking growth factor-induced phosphorylation of retinoblastoma tumor suppressor protein (Rb). In animal models of restenosis, TZDs inhibit intimal hyperplasia after mechanical injury in both insulin-sensitive and insulin-resistant vessels. Preliminary clinical studies using troglitazone demonstrate less intimal hyperplasia with this TZD after implantation of coronary stents in individuals with type 2 diabetes. Further large trials are needed to confirm that treatment with a TZD can protect against postangioplasty restenosis.

Intramural plasminogen activator inhibitor type-1 and coronary atherosclerosis

Altered expression of plasminogen activator inhibitor type-1 in vessel walls, reviewed here, might affect coronary atherogenesis. Upregulation might exacerbate vasculopathy by potentiating thrombosis and by inhibiting vascular smooth muscle cell migration, resulting in attenuation of thickness of elaborated fibrous caps implicated in the vulnerability of atheroma to rupture.

Association of insulin resistance, hyperleptinemia, and impaired nitric oxide release with in-stent restenosis in patients undergoing coronary stenting

BACKGROUND

Previously undiagnosed diabetes, impaired glucose tolerance, and insulin resistance are common in patients with acute myocardial infarction and coronary heart disease (CHD) and might be involved in early restenosis after stent implantation. To evaluate whether markers of insulin resistance syndrome, including leptin, and endothelial dysfunction are related to increased rate of early restenosis, we studied nondiabetic patients with CHD after successful coronary stenting.

METHODS AND RESULTS

Both patients with CHD undergoing coronary stenting (120 patients) and control subjects (58 patients) were submitted to an oral glucose tolerance test (OGTT). Fasting leptin levels and fasting and postglucose load insulin sensitivity were assessed. Endothelial function was measured by nitrite and nitrate release (NOx) during OGTT. More than 50% of patients treated with stent implantation presented impaired glucose tolerance or type 2 diabetes, which was previously undiagnosed. These patients also had higher glucose, insulin, and leptin levels than control subjects. Among the stented patients, insulin and leptin levels were higher in patients with restenosis than in patients without restenosis. A significant increase in NOx levels was found during OGTT both in patients without restenosis and in control subjects. On the contrary, NOx profiles were blunted in patients with restenosis. At multiple regression analysis, only DeltaAUC-NOx areas and insulin sensitivity index showed an independent correlation with the minimal lumen diameter at follow-up.

CONCLUSIONS

We demonstrated that insulin resistance and endothelial dysfunction are independent predictors of early restenosis after coronary stenting.

Neointimal formation after endovascular arterial injury is markedly attenuated in db/db mice

OBJECTIVE

A diabetic mouse model of accelerated neointimal formation would be a useful tool to understand the increased incidence of restenosis in patients with diabetes.

METHODS AND RESULTS

Femoral artery endoluminal wire injury was performed in diabetic insulin 2 Akita (ins2Akita) and leptin receptor db/db (leprdb/db) mutant mice. Neointima size in ins2Akita mouse arteries was unchanged compared with nondiabetic wild-type littermates. Although Ki67 labeling demonstrated similar rates of replication in the neointima of leprdb/db mouse arteries, neointimal formation in leprdb/db mice was surprisingly reduced by approximately 90% compared with nondiabetic lepr+/+ mice. Four hours after arterial injury, medial smooth muscle cell death was diminished in leprdb/db arteries, suggesting that the initial response to arterial injury was altered in leprdb/db mice.

CONCLUSIONS

These studies highlight a differential response to arterial injury in leprdb/db mice and suggest a potential role for leptin in the regulation of neointimal formation in response to arterial injury.