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.