The potential prognostic value of ultrasonic characterization (videodensitometry) of myocardial tissue in essential arterial hypertension

Diabetic cardiomyopathy: mechanisms, diagnosis and treatment

Independent of the severity of coronary artery disease, diabetic patients have an increased risk of developing heart failure. This clinical entity has been considered to be a distinct disease process referred to as 'diabetic cardiomyopathy'. Experimental studies suggest that extensive metabolic perturbations may underlie both functional and structural alterations of the diabetic myocardium. Translational studies are, however, limited and only partly explain why diabetic patients are at increased risk of cardiomyopathy and heart failure. Although a range of diagnostic methods may help to characterize alterations in cardiac function in general, none are specific for the alterations in diabetes. Treatment paradigms are very much limited to interpretation and translation from the results of interventions in non-diabetic patients with heart failure. This suggests that there is an urgent need to conduct pathogenetic, diagnostic and therapeutic studies specifically in diabetic patients with cardiomyopathy to better understand the factors which initiate and progress diabetic cardiomyopathy and to develop more effective treatments.

Microalbuminuria Is Associated with Reduced Cardiac Cyclic Variation of Integrated Backscatter Signal in Severe Hypertension

OBJECTIVE

Microalbuminuria (MA) as a marker of systemic vascular disease and left ventricular (LV) hypertrophy is associated with increased cardiovascular mortality and morbidity in patients with essential hypertension. The aim of this study was to investigate changes in cardiac cycle-dependent variation of integrated backscatter signals (CVIBS) in hypertensive patients with MA.

METHODS

Randomly selected 60 hypertensive patients (mean age 51 +/- 8) with uncontrolled blood pressure (BP) (>/=130 mmHg systolic and/or 85 mmHg diastolic) were included. All patients underwent urinary albumin excretion (UAE) measurements, 24-hour ambulatory BP monitoring, and LV echocardiographic examination. UAE was measured in two separate 24-hour urine collection and mean of two values was taken into consideration. Normotensive 20 healthy subjects served as controls. CVIBS values were obtained from mid-anteroseptal, mid-posterolateral, and mid-inferior areas at the papillary muscle level in the parasternal short-axis view. CVIBS was defined as the difference in integrated backscatter values between systole and diastole. CVIBS values in MA positive patients were compared with the values in MA negative patients and control subjects.

RESULTS

Twelve patients had MA (UAE 30 to 300 mg/day) while 48 patients had normal UAE (<30 mg/day). The wall thickness (at septum and posterior) and left ventricular mass index (LVMI) values were all significantly higher in hypertensive patients with MA (P < 0.01). The CVIBS values in MA positive group were significantly lower than the CVIBS values both in MA negative hypertensive patients and control subjects (P < 0.01).

CONCLUSION

This study demonstrates that in hypertensive patients a high LVMI is associated with reduced CVIBS values and MA appears to be a marker of hypertrophy.

Ultrasonic backscatter and diastolic function in hypertensive patients

This study was designed to assess whether ultrasonic reflectivity, evaluated by a real-time integrated backscatter analysis, was related to the severity of diastolic dysfunction, as studied by Doppler echocardiography in patients with essential hypertension. One hundred nine subjects were included in the study. Diastolic function was assessed by mitral-inflow Doppler ultrasound recordings. Backscatter cyclic variation and maximal intensity were measured in 6 regions throughout the left ventricle. The subjects were classified in 5 groups according to blood pressure and diastolic function: 29 normotensives with normal diastolic function (group 1), 18 hypertensives with normal diastolic function (group 2), 47 hypertensives with a delayed relaxation pattern (group 3), 11 hypertensives with a pseudonormal filling pattern (group 4), and 4 hypertensives with a restrictive filling pattern (group 5). The highest cyclic variation was found in groups 1 and 2, the lowest in groups 4 and 5 (5.7+/-0.2 dB in group 1 and 5.7+/-0.2 dB in group 2 versus 2.9+/-0.3 dB in group 4 and 2.1+/-0.4 dB in group 5; P<0.001), with intermediate values in group 3 (5.2+/-0.2 dB). Cyclic variation was inversely correlated with left ventricular chamber stiffness (P<0.05) and directly correlated with midwall fractional shortening (P<0.02) in all hypertensives. No differences in maximal intensity were found among the 5 groups of subjects. These results show an association between diminished cyclic variation of backscatter and deterioration of diastolic function in hypertensive patients. Thus, alterations in this parameter may be useful for the assessment of diastolic dysfunction in hypertension.

Ultrasonic backscatter and serum marker of cardiac fibrosis in hypertensives

Elevations in the serum concentration of the carboxy-terminal propeptide of procollagen type I (PIP) >127 microg/L have been found to predict severe myocardial fibrosis in hypertensive patients. This study was designed to assess whether ultrasonic reflectivity, evaluated by a real-time integrated backscatter analysis, was related to the severity of myocardial fibrosis as estimated by serum PIP. Thirty-four subjects were included in the study. Serum PIP was measured by specific radio immunoanalysis. Backscatter cyclic variation and maximal intensity were measured in 6 regions throughout the left ventricle. The subjects were divided into 3 groups: 14 normotensives with PIP <127 microg/L (group 1), 12 hypertensives with PIP <127 microg/L (group 2), and 8 hypertensives with PIP >127 microg/L (group 3). The highest cyclic variation was found in group 1 and the lowest in group 3 (5.78+/-0.25 versus 4.70+/-0.33 dB, P<0.05), with intermediate values in group 2 (5.10+/-0.27 dB). No differences in maximal intensity were found among the 3 groups of subjects. Using receiver operating characteristics curves, we observed that a cutoff of 2.90 dB for cyclic variation measured in the apex provided 75% sensitivity and 63% specificity for predicting PIP >127 microg/L in hypertensives, with a relative risk of 2.50 (95% CI, 0.72 to 34.70). These results show an association between diminished cyclic variation of backscatter and increased serum concentration of PIP in hypertension. Thus, the combination of these 2 parameters may be useful for the diagnosis of severe myocardial fibrosis associated with hypertension.

Clinical aspects of hypertensive myocardial fibrosis

Myocardial fibrosis is one of the histologic constituents of myocardial remodeling present in hypertensive patients with hypertensive heart disease. In fact, an exaggerated interstitial and perivascular accumulation of fibrillar collagens type I and type III has been found in the myocardium of patients with arterial hypertension and left ventricular hypertrophy. Hypertensive myocardial fibrosis has been shown to facilitate abnormalities of cardiac function, coronary reserve, and electrical activity that adversely affect the clinical outcome of hypertensive patients. Therefore, development of noninvasive tools for the monitoring of myocardial fibrosis and pharmacological strategies aimed to promote the regression of fibrosis could be of particular relevance in the clinical treatment of patients with hypertensive heart disease.