Changes in Estimated Glomerular Filtration after Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension.

Background: Balloon pulmonary angioplasty (BPA) is a novel treatment option for inoperable or persistent chronic thromboembolic pulmonary hypertension (CTEPH). Little is known about renal function in CTEPH patients undergoing BPA. Objectives: The aim of this study was to assess the frequency of contrast-induced acute kidney injury (CI-AKI) in patients with CTEPH undergoing BPA and to evaluate the relationship between hemodynamic and renal function. Methods: A total of 41 CTEPH patients were included and 250 consecutive BPA sessions were analyzed for frequency of CI-AKI. The serum creatinine (SC) concentration was measured and the glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease equation before and 72 h after each BPA procedure. CI-AKI was defined as an increase of 25% or 0.5 mg/dL in SC from the baseline value within 48-72 h of contrast administration. SC and GFR were assessed before and after 3-6 months of completing the BPA treatment and correlated with hemodynamic parameters. Results: The SC concentration and GFR did not change significantly within 72 h after BPA (+1%, p = 0.921, and +4%, p = 0.112, respectively). CI-AKI was noted in 2 cases (0.8%). Significant improvement was noted in GFR (75.4 +/- 21.2 vs. 80.9 +/- 22.4 mL/min/1.73 m(2); p = 0.012) in addition to improvement in right atrial pressure (RAP; 9.1 +/- 4.1 to 5.0 +/- 2.2 mm Hg; p < 0.001), mean pulmonary artery pressure (49.1 +/- 10.7 to 29.8 +/- 8.3 mm Hg; p < 0.001), cardiac index (CI; 2.42 +/- 0.6 to 2.70 +/- 0.6 L/min/m(2); p = 0.004), and pulmonary vascular resistance (9.42 +/- 3.6 to 4.4 +/- 2.3 Wood units; p < 0.001). In a subpopulation of 12 patients with impaired renal function at baseline, the relative increase in GFR was significantly correlated with relative improvement in CI (r = 0.060; p = 0.037), RAP (r = -0.587; p = 0.044), and mixed venous saturation (r = 0.069; p = 0.012). Conclusions: Hemodynamically effective BPA procedures improve renal function in patients with CTEPH with a minimal risk of CI-AKI in the course of treatment.