Screening for silent myocardial ischemia in diabetic patients

Low Levels of Vitamin D and Silent Myocardial Ischemia in Type 2 Diabetes: Clinical Correlations and Prognostic Significance

Vitamin D deficiency has a pathogenetic and prognostic role in coronary artery disease and a key role in pain transmission. Diabetic patients have a higher risk of silent myocardial ischemia (SMI) due to diabetic neuropathy. We evaluated the correlation between SMI and Vitamin D serum levels in type 2 diabetic patients and assessed whether SMI patients had a worse survival rate than their symptomatic counterpart. We enrolled 253 patients admitted in our Cardiology Unit and compared them with 50 healthy volunteers. We created three sub-groups: symptomatic MI group (125, 32.4%); SMI group (78, 25.7%), and no-MI group (50, 41.9%). 25(OH)D levels (nmol/L) were lower in the SMI group (34.9 ± 5.8) compared to those in the symptomatic MI (49.6 ± 6.1; p = 0.01), no MI (53.1 ± 6.2; p = 0.001), and control groups (62.1 ± 6.7; p = 0.0001). 25(OH)D levels predicted SMI in diabetic patients, with an inverted odds ratio of 1.11 (p = 0.01). Symptomatic MI group survival was higher than the SMI one (6-year survival rate: 83 vs. 69%; p = 0.01). Diabetic patients with SMI had a higher mortality risk and showed lower 25(OH)D levels than the symptomatic group. This suggests the crucial role that vitamin D has in the pathogenesis of SMI.

Six-year follow-up of a cohort of 203 patients with diabetes after screening for silent myocardial ischaemia

AIMS

To determine the prognosis of patients with Type 1 or Type 2 diabetes, 6 years after screening for silent myocardial ischaemia (SMI).

METHODS

Two hundred and three asymptomatic patients with diabetes underwent systematic SMI screening. From the results of this screening, they were allocated to one of three groups: patients (n = 171) with negative screening; patients (n = 32) with positive screening; and patients (n = 21) with positive screening and coronary stenosis. Six years after the initial assessment, all patients were re-assessed. All events [death, cardiac death, non-fatal major cardiac events (NFMCEs)--acute myocardial infarction, ventricular rhythm disorders, heart failure, unstable angina] were recorded.

RESULTS

Fifteen patients were lost to follow-up. Patients (n = 20) with positive SMI screening and coronary stenosis had a higher risk of NFMCEs (35% vs. 7%, P < 0.001), and a higher mortality rate (35% vs. 15%, P < 0.05) compared with patients (n = 157) with negative screening. SMI-positive patients (n = 31) had a higher NFMCE rate compared with negative SMI screening patients, although overall mortality rate was no different. Cancer was the leading cause of death (36.4%). In multivariate analysis, major cardiac events (cardiac death and NFMCE) were related to baseline age, body mass index and coronary stenosis (P < 0.01).

CONCLUSIONS

Patients with diabetes and SMI have a very poor prognosis as assessed by cardiac events or death, especially in the presence of coronary stenosis.

No effect of statin therapy on silent myocardial ischemia in patients with type 2 diabetes without manifest cardiovascular disease

OBJECTIVE

Coronary artery disease is the most important cause of mortality in patients with type 2 diabetes. We aimed to determine the prevalence of silent myocardial ischemia (SMI) and the effect of statin therapy on SMI in type 2 diabetic patients without manifest cardiovascular disease.

RESEARCH DESIGN AND METHODS

A randomized, placebo-controlled, double-blind trial was performed in 250 patients with type 2 diabetes without manifest cardiovascular disease. Patients were given either 0.4 mg cerivastatin or placebo daily. In August 2001, when cerivastatin was withdrawn from the market, cerivastatin 0.4 mg was replaced by 20 mg simvastatin without deblinding the study. The primary end point was the change in ischemic episodes, duration, and burden as measured by 48-h ambulatory electrocardiography (AECG) over 2 years.

RESULTS

At baseline, 47 of 233 (20%) evaluable ambulatory electrocardiograms showed evidence of ischemia. After 2 years, there was a trend toward more ischemia in both treatment groups, without significant differences between the changes in ischemic parameters (episodes P = 0.498; duration P = 0.697; burden P = 0.798) in the two treatment groups. Cardiovascular events occurred in 12 patients in the placebo group and in two patients in the statin group (P = 0.006). There was no relationship between these cardiovascular events and the presence of SMI at baseline.

CONCLUSIONS

SMI occurred in 20% of type 2 diabetes patients without manifest cardiovascular disease. There was no effect from 2 years of statin therapy on SMI. In contrast, we observed a significantly lower cardiovascular event rate on statin therapy. AECG may not be a proper tool for risk stratification in patients with type 2 diabetes.