Independent Echocardiographic Markers of Cardiovascular Involvement in Chronic Kidney Disease: The Value of Left Atrial Function and Volume.

BACKGROUND

Chronic kidney disease (CKD) is associated with increased cardiovascular mortality and morbidity, particularly ischemic heart disease and cardiomyopathy. Newer echocardiographic techniques such as myocardial strain analysis provides the opportunity to detect early myocardial dysfunction. The aim of this study was to examine echocardiographic parameters, in particular left atrial (LA) function and volume, in patients with CKD. A further aim was to determine echocardiographic parameters that are sensitive to detect cardiovascular involvement in early CKD.

METHODS

Seventy-six patients with stage 3 CKD (estimated glomerular filtration rate, 30-59 mL/min/1.73 m(2)) with hypertension and/or diabetes mellitus, without any previous cardiac illness, were prospectively recruited. These patients were compared with subjects matched for age, sex, and risk factors (hypertension and/or diabetes mellitus) with normal renal function and 76 healthy age-matched control subjects. Two-dimensional strain analyses of the left atrium and left ventricle were performed. Comprehensive echocardiographic examinations were performed in all participants, and traditional echocardiographic parameters including indexed LA volume (LAVI) and two-dimensional strain analysis of the left ventricle and left atrium were performed in all participants. Differences among the three groups on demographic, clinical, and echocardiographic parameters were examined.

RESULTS

LA systolic strain (20.9 ± 6.3% vs 27.4 ± 7.9%, P < .0001) and systolic and late diastolic strain rates were altered in the CKD group, while early diastolic strain rate was similar to that in the risk factor-matched group. LAVI was significantly larger in the CKD group compared with the risk factor-matched group and healthy control subjects (38.5 ± 10 vs 31.2 ± 9 vs 22.3 ± 5 mL/m(2), P < .0001). LV strain as well as LV systolic and early diastolic strain rates were similar in the CKD and risk factor-matched groups. LV late diastolic strain rate, a surrogate measure of LA contractile function, was, however, reduced in the CKD group. Forward logistic regression analysis showed LA global strain to be the most sensitive predictor for the presence of CKD, followed by LAVI; though LV late diastolic strain rate was reduced in the CKD group, it was not an independent predictor. Furthermore, the addition of LA strain to traditional echocardiographic parameters significantly increased the predictive power to detect cardiovascular involvement (C statistic = 0.65 vs C statistic = 0.84, P < .0001). Increased LAVI, reduced left ventricular global strain, and the presence of CKD were independent predictors of LA strain, while left ventricular mass index, E/e' ratio, and the presence of CKD were predictors of LAVI.

CONCLUSION

LA strain and LAVI are more sensitive parameters than traditional echocardiographic parameters as well as left ventricular strain in patients with early CKD. LA strain and LAVI may be useful to detect myocardial involvement in stage 3 CKD, and LA alterations may be consequent to increased activation of the renin-angiotensin-aldosterone pathway, causing myocardial fibrosis in CKD.