Assessment of diastolic and systolic left ventricular function by tissue doppler imaging in patients with type 2 diabetes mellitus: predictive value of B-natriuretic peptide

ABSTRACT

We sought to valuate left ventricular [LV] diastolic and systolic function in asymptomatic patients with type 2 diabetis mellitus [DM] using tissue Doppler [TD] analysis of mitral annulus dynamics and to investigate the potential value of brain natruretic peptide [BNP] as an early marker of systolic and/or diastolic failure in this group of patients. Epidemiologicall data document a greater risk of cardiovascular morbidity and mortality, particularly congestive heart failure [CHF], in patients with DM. Since BNP is a marker of early heart failure, it may serve to identify diabetic patients with preclinical abnormalities before progression to clinically evident diabetic cardiomyopathy. We studied 39 patients with type 2 DM [DM group] aged 37 to 70 years; without evidence of diabetic compications, hypertension, coronary artery disease, CHF, thyroid or overt renal disease and 15 age and sex matched healthy subjects [control]. Peak velocity and time-velocity integral were measured from TD tracings at the septal and lateral borders of the mitral annulus and the timing of the velocities in relation to the electrocardiogram. BNP was measured in plasma by chromatographic purification and separation using microseparation column C18 followed by enzyme immunoassat.The lateral TD systolic[S[ann]] velocity was significantly lower in DM group compared to controls [10.1 +/- 1.9 vs.11.5 +/- 2.0cm/sec.respectively;p> 0.005]. The septal and lateral TD early diastolic velocities E[ann] were significantly lower in DM group compared to controls [8.3 +/- 2.2 vs. 12.1 +/- 3cm/sec and12.1 +/- 3.8 vs. 17.5 +/- 3.8cm/sec respectively; both p> 0.00.01]. Thesetal and lateral TD time-velocity integral of E[ann] were significantly lower in DM group compared to controls [0.7+/0.3 vs.> 0.0001]. The septal and lateral TD early to late diastolic velocity ratio E[ann] /A[ann] were significantly lower in DM group compared to controls [0.8 +/- 0.3 vs. 1.4 +/- 0.5 cm and 1.1 +/- 0.5 vs. 1.9 +/- 0.6 cm respectively; both p> 0.0001]. Septal TD showed significantly prolonged regional ios-volumic relaxation time in DM group compared to controls [78.6 +/- 13.5 vs. 64.3 +/- 13.4msec respectively; p> 0.0001]. Plasma BNP level was significantly higher in DM group compared to controls [311.2 +/- 112.6 vs.38.2 +/- 4.8 pg/ml respectively; p> 0.0001].A significant negative correlation was detected between plasma BNP level and septal TD S[ann] velocity [r = -0.6; p> 0.001].A significant negative correlation was also detected between plasma BNP level and lateral and septal TD E[ann]/A[ann] velocity ratio [both r = -0.5; p> 0.001].Mistral annular contraction and relaxation velocities detected by TD imaging, are reduced in patients with type 2 DM compared to controls. The significantly higher plasma BNP level identified in diabetics correlated well with the degree of systolic and diastolic dysfunction detected by TD analysis of mitral annulus dynamics and so may be a useful marker for early heart failure in this group of patients