Can ECS predict CVD risk in patients undergoing peritoneal dialysis?

The presence of cardiovascular disease (CVD) in peritoneal dialysis (PD) patients puts them at a significantly higher echocardiographic calcium score (ECS) than those without CVD, indicating much greater vascular calcification burden in the former, according to a Singapore study.

“Although [ECS] was not found to be an independent determinant of CVD in this undersized study, it is a potentially useful tool to quantify vascular calcification in PD patients,” the researchers said.

A total of 125 patients on PD were included in this cross-sectional study. The researchers compared the ECS (range, 0‒8) between participants with and without CVD.

Of the patients, 54 had CVD and 71 did not. Those with CVD were older (69 vs 56 years; p<0.001) and had a higher prevalence of diabetes mellitus (DM; 81.5 percent vs 45.1 percent; p<0.001). [Singapore Med J 2023;64:379-384]

In addition, PD patients with CVD had lower diastolic blood pressure (72 vs 81 mm Hg; p<0.001), phosphate (1.6 vs 1.9 mmol/L; p=0.002), albumin (30 vs 32 g/L; p=0.001), parathyroid hormone (34.4 vs 55.8 pmol/L; p=0.002), total cholesterol (4.5 vs 4.9; p=0.047), low-density lipoprotein cholesterol (2.4 vs 2.8 mmol/L; p=0.019), and high-density lipoprotein cholesterol (0.8 vs 1.1 mmol/L; p=0.002).

Notably, ECS was higher in patients with CVD than in those without (2 vs 1; p=0.001).

“The Kidney Disease: improving Global Outcomes (KDIGO) guidelines recommend the assessment of valvular calcification by echocardiography to stratify cardiovascular risk in dialysis patients, but how this should be carried out is not specified,” the researchers said. [Kidney Int Suppl 2009;S1-130]

“We were able to detect a higher ECS in the CVD group despite similar intensities of dialysis between the groups as reflected by total weekly Kt/V values,” they added.

On multivariate analysis, however, only DM and age remained strong independent predictors of CVD. A previous study suggested that these two factors are known to cause both intimal and medial arterial calcification. [Am J Kidney Dis 2004;43:572-579]

No significant difference was observed in the prevalence of insulin use between the CVD and non-CVD groups (59 percent vs 50 percent; p=0.488).

Vascular compliance

Vascular stiffness predicts cardiovascular mortality and is associated with vascular calcification. Thus, patients with CVD had lower diastolic blood pressure because of the loss of vascular compliance. [Nephrol Dial Transplant 2004;19:1480-1488]

According to the researchers, clinical practices might influence the development of vascular calcification, with emerging evidence suggesting that calcium loading is a major predictor of cardiovascular death in dialysis patients.

“The use of ‘low-calcium’ dialysate should be made routine to retard coronary artery calcification, improve calcium and phosphate balance, and reduce cardiovascular mortality,” the researchers said. [J Am Soc Nephrol 2004;15:2208-2218; Hemodial Int 2007;11:340-348; J Ren Nutr 2006;16:41-46; Nephrol Dial Transplant 1992;7:1219-1225; Am J Kidney Dis 1992;20:367-371]

“The ECS, being a semi-quantitative tool, could be useful to monitor vascular calcification and its progression,” they noted.