Early subclinical ventricular dysfunction in patients with insulin resistance.

AIMS

The aim of our study was to evaluate the relationship between insulin resistance and the detection of precocious echocardiographic signs of heart failure in patients with cardiovascular risk factors.

METHODS

We enrolled 34 consecutive patients with cardiovascular risk factors. All patients underwent coronary angiography, echocardiography, and laboratory tests. Exclusion criteria were diabetes (fasting glucose greater than 126 mg/dl or treatment with insulin or oral hypoglycemic agents), coronary artery disease, creatinine above 1.5 mg/dl, left-ventricular hypertrophy, valvular heart disease, ejection fraction below 50%, atrial fibrillation, or other severe arrhythmia. The presence of insulin resistance was assessed by using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). Ventricular function was investigated by echocardiography.

RESULTS

Distinguishing patients with insulin resistance, based on the median value of HOMA-IR (<4.06 and >4.06), we observed that in the group with higher levels of HOMA-IR, there were echocardiographic signs of subclinical ventricular dysfunction statistically more frequent (E/A in group with HOMA <4.06: 1.159 + 0.33 vs. group with HOMA >4.06: 0.87 + 0.29, P = 0.0136; E/E': 6.42 + 4 vs. 15.52 + 3.26, P = 0.001; Tei index: 0.393 + 0.088 vs. 0.489 + 0.079, P = 0.0029; S wave: 0112 + 0.015 vs. 0.114 + 0.027, P = 0.0001; ejection fraction 59.11 + 4.75 vs. 58.88 + 6.81, P = 0.9078). Grade II diastolic dysfunction was observed in 5 patients, grade I in 12 patients, and 17 patients had normal diastolic function. On multivariate analysis, HOMA-IR (P = 0.0092), hypertension (P = 0.0287), waist circumference (P = 0.0009), high-density lipoprotein (P = 0.0004), and fasting blood glucose (P = 0.0003) were variables independently associated with diastolic dysfunction. On analysis of covariance, we found that the variables that influence diastolic dysfunction are HOMA-IR, waist circumference, BMI, and age, and that the only variable that influences Tei index is HOMA-IR.

CONCLUSION

Insulin resistance is frequently associated with subclinical left-ventricular dysfunction. Patients with cardiovascular risk factors and increased HOMA-IR levels, although without diabetes mellitus, overt coronary artery disease, or hypertensive cardiomyopathy, may represent a target population for screening programs, recommended changes in lifestyle, and possibly the use of pharmacological interventions to prevent the onset of heart failure.