[Risk factors for pulmonary hypertension at the predialysis stage of chronic kidney disease].

AIM

To investigate the incidence and risk factors of pulmonary hypertension (PH) in patients with chronic kidney disease (CKD).

SUBJECTS AND METHODS

86 patients (53% men, 47% women; mean age, 45±13 years) with nondiabetic CKD were examined. According to the magnitude of glomerular filtration rate (GFR) decrease, all the patients were divided into 3 groups: 1) 33 patients with a GFR of 89--45 ml/min; 2) 33 with a GFR of 44--15 ml/min; 3) 20 with a GFR of <15 ml/min who were treated with hemodialysis. A control group consisted of 20 individuals with preserved kidney function (a GFR of >90 ml/min). Physical examination and transthoracic echocardiography were performed in all the patients. The serum concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNT) and cystatin C were determined.

RESULTS

PH was detected in 21 (24.4%) of the 86 patients with CKD. As CKD progressed, its prevalence in Groups 1, 2, and 3 increased, amounting to 18.2, 24.2, and 35%, respectively. The most predictably significant risk factors for PH were hypertension (ρ=0.35; р=0.001) and kidney dysfunction (creatinine (ρ=0.23; р=0.02). Elevated pulmonary artery systolic pressure (PASP) correlated with right ventricular (RV) dimension index (ρ=0.45; р<0.0001), right atrial volume index (ρ=0.3; р=0.02), left atrial volume index (ρ=0.3; р=0.009), and left ventricular mass index (ρ=0.35; р=0.03). In all the patients with CKD in the presence of PH, the NT-proBNP level was significantly higher than in its absence: 37.43 (5.83; 59.84) and 8.54 (5.1; 20.43) fmol/ml, respectively (р=0.01). Positive correlations were found between the level of cystatin C and the presence of PH (ρ=0.32; р=0.003). Analysis of the ROC curve (AUC=0.718; р=0.03) in the predialysis-stage CKD groups (n=66) revealed that the cystatin C level of > 1045 ng/ml with a sensitivity of 71% and a specificity of 60% suggested that PH was present. Multivariate analysis showed that the factors correlating with the presence of PH were NT-proBNP (β=0.34; р=0.008) and RV dimension index (β=0.3; р=0.002).

CONCLUSION

EchoCG reveals PH in almost 25% of the patients with CKD, which occurs at its predialysis stage. Elevated PASP is associated with myocardial structural changes. Traditional risk factors (hypertension) and diminished kidney function affect the development of PH.