Can myocardial performance index predict the presence of silent ischemia in asymptomatic type 2 diabetic patients?

BACKGROUND: Coronary artery disease (CAD) is an important cause of morbidity and mortality in patients with diabetes. Silent myocardial ischemia (SMI) is common in patients with diabetes and is associated with poorer prognosis. Myocardial performance index "Tei index" that reflects both left ventricular (LV) systolic and diastolic function. The aim of our study was to test the value of Tei index in prediction of SMI in asymptomatic patients with type 2 diabetes. PATIENTS AND METHODS: Asymptomatic patients with type 2 diabetes were included in our study. We excluded patients with known CAD, previous revascularization, low ejection fraction, or abnormal ECG from the study. All patients had undergone history taking and clinical examination, ECG, echocardiography with measuring of Tei index and Holter monitoring for detecting silent ischemia. RESULTS: A total of 200 patients were recruited. We divided our patients into two groups: Group I: 64 patients with SMI, Group II: 136 patients without SMI. There was no significant difference between the two groups regarding clinical and conventional echocardiographic data. Tei index was significantly higher in patients with silent ischemia (P<.00001). Sensitivity, specificity, positive, and negative predictive values of Tei index ≥0.6 in prediction of Holter detected silent ischemia were 85.9%, 90%, 78.6%, and 88.6%, respectively. We found a significant positive correlation between Tei index and number of ischemic episodes (r=.366, P=.0029). CONCLUSION: Measuring Tei index is helpful in predicting the presence of silent ischemia in asymptomatic patients with type 2 diabetes.

Mean platelet volume and its relation to insulin resistance in non-diabetic patients with slow coronary flow.

BACKGROUND: Increased mean platelet volume is a central process in the pathophysiology of coronary heart disease. Insulin resistance contributes to increased platelet activation. AIM: To assess the mean platelet volume and its possible relationship with insulin resistance in non-diabetic patients with slow coronary flow. METHODS AND SUBJECTS: The study included 60 patients with slow coronary flow and 20 subjects (controls) with normal coronary arteries. Slow coronary flow patients were divided into 2 groups, insulin resistant (32 patients) and insulin sensitive (28 patients) according to the homeostasis model assessment of insulin resistance index (HOMA-IR). RESULTS: Patients with slow coronary flow had significantly higher mean platelet volume values (7.9±0.47 vs. 7.1±0.5, p<0.01), insulin level (10.8±3.2 vs. 8.2±1.4, p<0.01), and HOMA-IR scores (2.72±0.85 vs. 1.84±0.19, p<0.01). These parameters were significantly higher in insulin-resistant patients than in insulin-sensitive ones. The mean platelet volume was correlated with HOMA-IR (r=0.52, p<0.01) and insulin level (r=0.58, p<0.01). In multivariate analysis, mean platelet volume and HOMA-IR were independent predictors of mean TIMI frame count {(B±SE=0.562±2.95, p<0.01) and (B±SE=0.538±2.46, p<0.01), respectively}. CONCLUSION: Patients with slow coronary flow have increased mean platelet volume which was associated with insulin resistance in non-diabetic slow coronary flow patients. TIMI frame counts correlated with mean platelet volume and increased insulin resistance. Thus, insulin resistance and platelet activity may have a role in the pathogenesis of slow coronary flow. Also, they may have a possible benefit as follow-up markers in non-diabetic patients with slow coronary flow.

Endothelial-mediated coronary flow reserve and its relation to mitral annular tissue Doppler velocities in offspring of hypertensive parents.

BACKGROUND: Although coronary flow reserve (CFR) is reduced in hypertensive patients, data regarding the endothelial response of coronary vasomotion and its relation to left ventricular (LV) function in their offspring is limited. OBJECTIVE: To investigate the endothelial response of coronary flow, using cold pressor test (CPT), in offspring of hypertensive parents and its impact on LV diastolic function. SUBJECTS AND METHODS: The study population consisted of 32 healthy young offspring (mean age 23.5 ± 7.1 years) of hypertensive parents and 26 aged matched volunteers (healthy offspring of normotensive parents) as controls. Coronary blood flow velocities were recorded in all subjects at rest and after CPT; a stimulus that can be considered totally endothelium-dependent. CFR was calculated as the ratio of hyperemic-to-resting diastolic peak velocities. Doppler echocardiographic assessment was performed using both conventional and tissue Doppler assessment. RESULTS: Coronary diastolic peak velocities at rest was comparable between the two groups (27.1 ± 6.2 vs 26.4 ± 5.8; P > 0.05); but the velocities were significantly lower after CPT in offspring of hypertensive parents (P < 0.02), with highly significant lower CFR (P < 0.0001). Conventional echo-Doppler variables were comparable in both groups, whereas tissue Doppler assessment demonstrated significant LV diastolic dysfunction among offspring of hypertensive parents. The CPT-CFR was significantly correlated to tissue Doppler diastolic dysfunction in this group (For Em, Am and Em/Am, r was 0.65, 0.59 and 0.61, respectively, and P < 0.001). CONCLUSION: Offspring of hypertensive parents have coronary endothelial dysfunction that appears in response to physiological stimuli (CPT). The coronary endothelial dysfunction is associated with latent LV diastolic dysfunction.

Early detection of silent ischemia and diastolic dysfunction in asymptomatic young hypertensive patients.

BACKGROUND: There is an association between coronary artery disease (CAD) and increased carotid-intima media thickness (IMT), a surrogate index of atherosclerosis. This association is poorly studied in asymptomatic subjects with risk factors of CAD. AIM: To study the relationship between carotid-IMT, coronary flow reserve (CFR) and cardiac function in asymptomatic young hypertensive subjects. METHODS: This study includes 82 asymptomatic young subjects with essential hypertension, and 78 healthy control subjects. Carotid-IMT was assessed with B-mode ultrasonography. Treadmill exercise test, CFR and echo Doppler study were performed for all subjects. RESULTS: Hypertensive group had a significantly higher carotid-IMT (0.91 + 0.13 vs. 51 ± 0.09, P < 0.01), and a significantly lower coronary flow velocity reserve (1.9 ± 0.44 vs. 3.2 ± 0.44, P < 0.003) than in control subjects, especially in those with stress induced myocardial ischemia. Multiple linear regression analyses shows that increased carotid-IMT was related to a reduced CFR (r = -843, P < 0.001) and a lower diastolic function (E/e″, r = -512, P < 0.003) in asymptomatic hypertensives. In addition the carotid-IMT showed a significant correlation with family history of hypertension in these subjects (r = 653, P < 0.002). CONCLUSION: Carotid-IMT increases significantly in asymptomatic young hypertensive patients. It has a relationship with stress-induced myocardial ischemia, decrease CFR and incipient diastolic dysfunction in those patients. It could be considered as an index for subclinical atherosclerosis and diastolic dysfunction in asymptomatic subjects with risk factors for CADs.