Effect of the progression of chronic kidney disease on left atrial function

Objective To explore the changes of left atrial function and volume in the progression of chronic kidney disease using two-dimensional spot tracking. Method A total of 103 patients with CKD were selected and divided into 3 groups according to CKD stage: 50 patients in group A (stage 1 and 2), 29 patients in group B (stage 3 and 4), and 24 patients in group C (peritoneal dialysis patients). The traditional echocardiography and left atrial speckle tracking technology was used to measure left atrial peak strain, early diastolic left atrial strain, and left atrial contraction strain in all patients, and the left atrial time-volume curve was obtained to calculate the total emptying rate, passive emptying rate and active emptying rate. SNK test was used to compare the differences among groups. Results Compared with stage 1 and stage 2 patients, the left atrial peak strain and peak strain rate and the early diastolic left atrial strain were reduced in the group of stage 3 and stage 4 patients, and the differences were statistically significant [(35.1±6.0)% vs (30.9±7.7)%, (2.11±0.55)s-1vs (1.83±0.45)s-1, (25.4±6.1)% vs (18.1±5.7)%, q=3.70, 3.28 and 7.77, both P<0.05]. The prevalence rate of hypertension, IVS and left atrial contraction strain increased [(56% vs 86.2%), (9.8±1.4) mm vs (11.1±2.1) mm, (9.6±3.9)% vs (12.8±5.7)%, χ2=7.59, P=0.006; q=4.09 and 4.22, both P<0.05]. The peak strain and early diastolic strain of peritoneal dialysis patients reduced [(35.1±6.0)% vs (29.5±7.5)%, (25.4±6.1)% vs (19.7±4.7)%; q=4.68 and 5.70, both P<0.05]. The prevalence rate of hypertension, LVM, LVDD, LAVI, LAVmax, LAVmin and LAV pre-A and the prevalence of left atrial enlargement increased [(56.0% vs 95.8%), (159.5±45.2) g vs (201.7±66.0)g, (16.0% vs 54.2%), (28.1±8.0) ml vs (35.2±9.0) ml, (42.1±15.7) ml vs (57.0±21.1) ml, (13.1±6.7)ml vs 22.9±19.8) ml, (13.1±6.7) ml vs (22.9±19.8) ml, (27.1±11.3) ml vs (38.2±14.6) ml, χ2=12.01 and 11.61, both P=0.001; q=4.46, 3.37, 4.84, 4.78 and 4.95, both P<0.05]. Compared with stage 3 and 4 patients, the incidence of diabetes and left atrial contraction strain in peritoneal dialysis patients reduced [(41.4% vs 8.3%), (12.8±5.7% vs (9.7±4.5), χ2=7.4, P=0.007; q=13.45, P<0.05], the rate of left ventricular diastolic dysfunction, LAVI, LAVmax and LAV pre-A increased [(13.8% vs 54.2%), (28.6±8.7ml vs (35.2±9.0) ml, (41.3±17.5) ml vs (57.0±21.1) ml, (14.1±9.2) ml vs (22.9±19.8) ml, (28.2±13.8) ml vs (38.2±14.6) ml, χ2=9.82, P=0.002, q=2.81, 4.58, 3.85 and 4.00, both P<0.05]. Compared with group A, the left atrial reservoir and conduit function of group B decreased, but left atrial volume parameters (including LAVI, left atrial maximum volume, minimum volume and volume before left atrial contraction obtained by speckle tracking) had no significant difference. Left atrial total emptying rate, rate of passive and active emptying can be calculated through left atrial time-volume curve. However, the above three parameters had no significant difference among three groups. Conclusion The reservoir and conduit function of left atrium decreased with the aggravation of chronic renal disease, but compared with CKD1, 2 and peritoneal dialysis patients, the left atrial contraction function of CKD3, 4 stage patients increased. In addition, the left atrial strain parameters is more sensitive than the left atrial volume parameters, and we can find the changes of left atrial function before the left atrial volume changes. Key words: Chronic kidney disease; Echocardiography; Left atrial; Strain; Cardiac function; Peritoneal dialysis