Potential Risk Factors Identified for RRT Among Patients With PH

New study findings show that creatinine level upon intensive care unit (ICU) admission and right atrial pressure (RAP) may be predictors of the need for renal replacement therapy among patients who have acute decompensated pulmonary hypertension (PH), a condition that is frequently accompanied by acute kidney injury (AKI).

Acute decompensated PH often is characterized by systemic congestion and right ventricular flow output that worsen quickly, necessitating the need for renal replacement therapy (RRT) among those with comorbid AKI. “However, predictors and timing for RRT in acute decompensated PH are unknown, and mortality of patients who require this therapy is high,” wrote the study authors in Cureus. “There are potential risks in administrating RRT in this population, including hemodynamic instability, bleeding, and complications related to venous access and dialysis circuit.”

Their multicenter retrospective cohort study included patients with pulmonary arterial hypertension (PAH) and nonsurgical chronic thromboembolic pulmonary hypertension (N = 73) who had an unplanned ICU admission between 2014 and 2019 in Sao Paulo, Brazil. Clinical, functional, hemodynamic, and lab data from 3 points were evaluated: the 6 months leading up to the ICU admission, at ICU admission, and during the ICU stay.

Among the 73 patients in this analysis—outcomes were compared between those who did and did not need RRT—16.4% required the treatment during their ICU stay. These patients were older (median [IQR] age, 51 [43-61] years) compared with the non-RRT group (47 [34-58] years), and although fewer had PAH (33.3% vs 70.5%), close to 3 times as many were deemed high-risk patients (66.7% vs 26.2%).

Patients in the RRT group had higher median results on several hemodynamic measures:

• Median pulmonary arterial pressure: 60 (45-66) vs 56 (50-66) mm Hg (P = 0.95)
• Pulmonary artery wedge pressure: 15 (13-17) vs 11 (8-15) mm Hg (P = 0.06)
• RAP: 22 (18-25) vs 13 (8-17) mm Hg (P < .01)
• Cardiac output: 4.1 (3.6) vs 3.6 (2.8-4.6) L/min (P = 0.29)

The most common reason for PH decompensation was infection in 50% of the RRT group and 47.5% in the non-RRT group.

In addition, patients in the RRT group had higher median creatinine, at 3.16 (2.12-3.9) vs 1.26 (0.89-2.16) mg/dL; all patients had a history of intravenous furosemide (a diuretic) or dobutamine, respectively, compared with 96.7% and 82.0% in the non-RRT group; and 70.0% vs 27.9% needed vasopressors (ie, norepinephrine, vasopressin, or epinephrine) due to their low blood pressure. The most common reason for RRT was negative fluid balance.

Overall, having higher creatinine level was linked to higher odds of needing RRT in unadjusted models and when gender and PH group were considered. The unadjusted odds ratio (OR) was 2.87 (95% CI, 1.49-5.52) and the adjusted OR was 2.70 (95% CI, 1.35-5.40). For RAP, only the unadjusted OR was high enough to denote a possible link with need for RRT, at 1.12 (95% CI, 1.02-1.24); the adjusted OR was 1.08 (95% CI, 0.97-1.20).

A decision tree model also determined that creatinine level was the “most important discriminating factor” at predicting RRT use, followed by RAP.

A final analysis of overall and in-hospital and 90-day mortality, respectively, showed far more patients in the RRT group vs the non-RRT group died: 75.0% vs 34.4% and 83.3% vs 42.6%.

“RRT is recognized as a reasonable treatment for patients with acute left heart failure with refractory fluid overload, cardiorenal syndrome, or diuretic resistance,” the study authors highlighted. “However, RRT’s role in acute decompensated PH is still unclear. Concerns do exist, especially regarding the effect of RRT on short- and long-term outcomes.”

Although their decision tree model did suggest potential predictors of RRT use from acute decompensated PH, further studies should investigate the optimal time to initiate RRT, who are the best candidates for this treatment, the best treatment modality, and how to avoid complications.

Reference

Garcia M, Souza R, Caruso P. Renal Replacement Therapy in Patients With Acute Decompensated Pulmonary Hypertension Admitted to the Intensive Care Unit. Cureus. Published online September 5, 2022. doi:10.7759/cureus.28792