Relation of restenosis after excimer laser angioplasty to fasting insulin levels

In-hospital daily insulin dose predicts long-term adverse outcome in patients with diabetes with ST-elevation myocardial infarction treated with successful primary percutaneous angioplasty

INTRODUCTION

Early initiation of reperfusion therapy including primary percutaneous coronary revascularization (PPCI) has been recognized as a crucial factor determining clinical outcomes in the acute phase of myocardial infarction. In unstable patients with type 2 diabetes mellitus (T2D) the clear benefit from PPCI was proven. We aim to evaluate the prognostic value of factors describing glycometabolic state on admission in patients with T2D undergoing PPCI in acute ST-elevation myocardial infarction (STEMI).

MATERIAL AND METHODS

Prospective analysis of clinical and laboratory variables (mean daily short acting exogenous insulin dose (DID), admission blood glucose, glycated hemoglobin (HbA1c), microalbuminuria) was performed in 112 consecutive patients with T2D with STEMI who underwent PPCI. Women comprised 58% of the group.

RESULTS

Insulin dosing was targeted to obtain a mean daily glucose level < 7.8 mmol/l. During 12-month follow-up 33 (29.5%) major adverse cardiac events (major adverse cardiac events (MACE) consisting of death, reinfarction, and repeated target vessel revascularization) were reported. Microalbuminuria was present in 68 (60.5%) patients. The mean HbA1c level was 7.9%. In the multivariate logistic regression model only DID > 44 IU remained an independent risk factor for MACE (p = 0.02, OR = 5.2).

CONCLUSIONS

In patients with diabetes with STEMI treated with PPCI, simple measurement of DID during hospitalization can add valuable prognostic information about the future risk of MACE.

Predictors of restenosis after percutaneous coronary intervention using bare-metal stents: a comparison between patients with and without dysglycemia

The objective of this study was to identify intravascular ultrasound (IVUS), angiographic and metabolic parameters related to restenosis in patients with dysglycemia. Seventy consecutive patients (77 lesions) selected according to inclusion and exclusion criteria were evaluated by the oral glucose tolerance test and the determination of insulinemia after a successful percutaneous coronary intervention (PCI) with a bare-metal stent. The degree of insulin resistance was calculated by the homeostasis model assessment of insulin resistance (HOMA-IR). Six-month IVUS and angiogram follow-up were performed. Thirty-nine patients (55.7%) had dysglycemia. The restenosis rate in the dysglycemic group was 37.2 vs 23.5% in the euglycemic group (P = 0.299). The predictors of restenosis using bivariate analysis were reference vessel diameter (RVD): pound2.93 mm (RR = 0.54; 95%CI = 0.05-0.78; P = 0.048), stent area (SA): <8.91 mm(2) (RR = 0.66; 95%CI = 0.24-0.85; P = 0.006), stent volume (SV): <119.75 mm(3) (RR = 0.74; 95%CI = 0.38-0.89; P = 0.0005), HOMA-IR: >2.063 (RR = 0.44; 95%CI = 0.14-0.64; P = 0.027), and fasting plasma glucose (FPG): < or =108.8 mg/dL (RR = 0.53; 95%CI = 0.13-0.75; P = 0.046). SV was an independent predictor of restenosis by multivariable analysis. Dysglycemia is a common clinical condition in patients submitted to PCI. The degree of insulin resistance, FPG, RVD, SA, and SV were correlated with restenosis. SV was inversely correlated with an independent predictor of restenosis in patients treated with a bare-metal stent.

Integrated Management of Patients with Diabetes Mellitus and Ischemic Heart Disease: PCI, CABG, and Medical Therapy

Modern coronary revascularization strategies are based on studies performed in the 1970s and 1980s that compared coronary artery bypass surgery with standard medical therapy available at the time. Studies comparing surgical and percutaneous revascularization followed, demonstrating similar long-term outcome among thousands of randomized patients. The largest of these trials, the Bypass Angioplasty Revascularization Investigation (BARI), cast doubt on the generalizability of these findings to all subgroups, finding that patients with diabetes mellitus and multivessel disease had worse long-term outcome with an initial strategy of percutaneous transluminal coronary angioplasty (PTCA). Indeed, patients with diabetes mellitus are at increased risk for cardiovascular morbidity and mortality, while the benefit of standard therapies in these patients is attenuated by the underlying metabolic abnormalities and significant comorbidities associated with the diabetic state. However, surgical and percutaneous revascularization techniques continue to evolve. Similarly, modern medical therapy is markedly superior to that available during these early studies, with demonstrable benefit in primary and secondary prevention of vascular events in both diabetic and nondiabetic patients. Ongoing trials will define the impact of current treatment modalities in this important and growing population.

Effect of rosiglitazone on restenosis after coronary stenting in patients with type 2 diabetes

BACKGROUND

Thiazolidinediones have been shown to have an antiproliferative vascular effect in experimental models. We sought to study the effect of rosiglitazone on in-stent restenosis in patients with established type 2 diabetes.

METHODS

Patients with treated type 2 diabetes (mean duration 5.5 +/- 7.5 years) referred for coronary stenting were randomized in a double-blind fashion to receive oral rosiglitazone or placebo for 6 months. Quantitative coronary angiography and intravascular ultrasound data were obtained at baseline and follow-up. Plasma plasminogen activator inhibitor-1 levels were prospectively measured.

RESULTS

Sixteen patients were enrolled. There were no significant differences in follow-up in-stent luminal diameter stenosis measured by quantitative coronary angiography or in-stent luminal area stenosis and neointimal volume index obtained by intravascular ultrasound, nor were there any differences in plasma plasminogen activator inhibitor-1 levels after long-term use despite improvement in diabetes control and insulin sensitivity.

CONCLUSIONS

Rosiglitazone, given at the time of stent implantation in treated diabetics, did not reduce in-stent restenosis in this small series. The vascular biological effects of this agent await further clarification in humans and evaluation in larger clinical trials.

Hyperinsulinemia as a risk factor for restenosis after coronary balloon angioplasty

The present study evaluated whether hyperinsulinemia is a predictor of restenosis after coronary balloon angioplasty in 69 patients who underwent elective coronary balloon angioplasty; patients were excluded if they were known diabetics being treated with insulin. Quantitative coronary angiography was performed before and after angioplasty and at follow-up. Restenosis was defined as the presence of > or = 50% stenosis at follow-up. Plasma insulin responses before, 30, 60, and 120 min after 75 g glucose load (OGTT) were measured. Plasma insulin levels were higher in patients with restenosis than in patients without restenosis. Minimal lumen diameter at follow-up was smaller, and percent diameter stenosis at follow-up was higher and late loss was greater in the highest sum of insulin levels during OGTT (sigma insulin) quartile (0.95+/-0.15 vs 1.47+/-0.09 mm, p=0.005; 66.3+/-5.8 vs 40.5+/-3.3%, p=0.0003; 0.90+/-0.15 vs 0.49+/-0.08 mm, p=0.02). Even after adjustment for coronary risk factors and administration of angiotensin converting enzyme inhibitors, the association of hyperinsulinemia with restenosis leads to the conclusion that hyperinsulinemia is a strong risk factor for restenosis.

Restenosis, late vessel occlusion and left ventricular function six months after balloon angioplasty in diabetic patients

OBJECTIVES

We studied angiographic outcome and its predictors after traditional coronary balloon angioplasty in diabetics. We further examined whether changes in ejection fraction were influenced by the status of the dilated site(s) at follow-up.

BACKGROUND

Recent studies have suggested that diabetics have a particularly poor outcome after balloon angioplasty. The reasons for this observation are not known.

METHODS

We investigated procedural and six-month angiographic outcome, analyzed by quantitative coronary angiography, and left ventricular function in 485 consecutive diabetics (627 lesions) treated by balloon angioplasty without stent implantation.

RESULTS

The procedure was successful in 455 (94%) patients; angiographic follow-up was available in 377 patients (83%). At follow-up, the rates of restenosis and total occlusion were 62% and 13%, respectively. Five independent predictors of restenosis were identified: the presence of organ damage, a saphenous vein graft (SVG) angioplasty, a bifurcation lesion, a Thrombolysis in Myocardial Infarction (TIMI) flow <3 preprocedure and the degree of residual stenosis. Four independent predictors of vessel occlusion were identified: treatment with insulin, a SVG angioplasty, a TIMI flow <3 preprocedure and the degree of residual stenosis after angioplasty. Late vessel occlusion at angioplasty site(s) was observed in 15% of patients, ranging from 11% for a one-site procedure to 37% for a three-site procedure. This complication was associated with a decrease in ejection fraction at follow-up (-6.2 +/- 9.9%, p = 0.0001), whereas no significant change was observed in patients without occlusion.

CONCLUSIONS

This study shows that late vessel occlusion is a frequent mode of restenosis in diabetic patients and is associated with a significant decrease in ejection fraction. This could partly explain the poor long-term clinical outcome reported in such patients after traditional balloon angioplasty.

Midterm angiographic outcome of single-vessel intracoronary stent placement in diabetic versus nondiabetic patients: a matched comparative study

BACKGROUND

It remains controversial whether diabetes is associated with an increased risk of restenosis after intracoronary stenting.

METHODS AND RESULTS

We selected 42 diabetic patients and an equal number of nondiabetic patients with follow-up angiographic restudy after single-vessel stenting, matched for 4 important stent-related and angiographic variables (stent design, reference vessel size and expanded stent diameter, coronary vessel treated, and poststent residual diameter stenosis). The 2 patient groups did not differ in their baseline lesion severity and acute luminal gain. At 5-month angiographic assessment, the observed in-stent restenosis rate was significantly higher in diabetic than nondiabetic patients (40.5% vs 16.7%, P = 0.0157). It was highest in diabetic patients who received small stents <3.0 mm in diameter and intermediate in diabetic patients who received larger stent sizes (55% vs 27%, P = 0.0675). The frequency of restenosis in nondiabetic patients, however, was low; it was 18% and 15% in those who received small stents and larger stents, respectively (P = 0.7823).

CONCLUSIONS

Our data suggest that diabetes predisposes to an increased risk of in-stent restenosis, particularly in small vessels.

Relationship between diabetes mellitus and long-term survival after coronary bypass and angioplasty

BACKGROUND

Recent subgroup analyses of randomized trials have suggested that percutaneous intervention in diabetic patients with multivessel disease results in higher mortality than coronary artery bypass graft surgery (CABG). We studied the relationship between diabetes and survival after revascularization in a large prospective cohort of patients with multivessel coronary artery disease.

METHODS AND RESULTS

By analyzing data for 3220 patients (24% diabetic) with symptomatic two- or three-vessel coronary disease who were undergoing percutaneous transluminal coronary angioplasty (PTCA) or CABG at Duke University Medical Center between 1984 and 1990, we found that at 5 years, unadjusted survival in the group of patients undergoing CABG was 74% in diabetics and 86% in nondiabetics. Similarly, 5-year survival among PTCA patients was 76% in diabetics and 88% in patients without diabetes. After adjustment for baseline characteristics, diabetic patients receiving either PTCA or CABG had significantly poorer survival than nondiabetics (chi2=43.56, P<.0001). Unlike previous studies, however, there was no significant differential effect of diabetes on outcome between patients treated with PTCA and those treated with CABG (chi2=0.01, P=.91).

CONCLUSIONS

Although diabetes was associated with a worse long-term outcome after both PTCA and CABG in patients with multivessel coronary artery disease, the effect of diabetes on prognosis was similar in both treatment groups. Thus, our findings support the concept that the choice of initial revascularization strategy should not be based exclusively on a history of diabetes but rather should rely on other factors, such as angiographic suitability and clinical status.

Potential mechanisms promoting restenosis in diabetic patients

Diabetes is associated with greater restenosis rates after successful balloon angioplasty. The metabolic alterations that occur as a result of hyperglycemia or hyperinsulinemia can accelerate many of the pathophysiologic processes that lead to restenosis. Diabetes results in endothelial dysfunction and accelerated platelet deposition, which increase the propensity to thrombosis. Several growth factors known to promote the restenosis process are overexpressed in the presence of hyperglycemia. Advanced glycosylation promotes inflammatory cell recruitment and smooth muscle cell proliferation. Many of the potential mechanisms promoting restenosis in diabetic patients can be ameliorated by improved metabolic control.