A prospective echocardiographic evaluation of pulmonary hypertension in chronic hemodialysis patients in the United States: prevalence and clinical significance

Abstract

Background: Pulmonary hypertension (PH), a disease which carries substantial morbidity and mortality, has been reported to occur in 25%-45% of dialysis patients. No prospective evaluation of the prevalence or clinical significance of PH in chronic dialysis patients in the United States (US) has been undertaken.

Methods: Echocardiograms were performed prospectively in chronic hemodialysis patients prior to dialysis at a single dialysis center. PH was defined as a tricuspid regurgitant jet ≥2.5 m/s and "more severe PH" as ≥3.0 m/s. Clinical outcomes recovered were all-cause hospitalizations and death at 12 months.

Results: In a cohort of 90 patients, 42 patients (47%) met the definition of PH. Of those, 18 patients (20%) met the definition of more severe PH. At 12 months, mortality was significantly higher in patients with PH (26%) compared with patients without PH (6%). All-cause hospitalizations were similar in patients with PH and without PH. Echocardiographic findings suggesting impaired left ventricular function and elevated pulmonary capillary wedge pressure were significantly associated with PH.

Conclusion: This prospective cross-sectional study of a single dialysis unit suggests that PH may be present in nearly half of US dialysis patients and when present is associated with increased mortality. Echocardiographic findings demonstrate an association between elevated filling pressures, elevated pulmonary artery pressures, and higher mortality, suggesting that the PH may be secondary to diastolic dysfunction and compounded by volume overload.

Keywords: diastolic dysfunction; pulmonary hypertension; renal failure.

Figure 1

Kaplan Meier survival estimates based on presence, absence, and degree of PH by TR jet: group 1 = no TR, and TR < 2.5 m/s; group 2 = TR 2.5–3.0 m/s; group 3 = TR > 3.0 m/s (P = 0.0004). At 12 months, mortality was 44% (8/18) in group 3 versus 6% (3/48) and 12.5% (3/24) in groups 1 and 2, respectively (P = 0.001). The P = 0.0004 is based on the time to event analysis and signifies an overall difference between the 3 curves/groups. P = 0.001 is based on a chi-square test for the number of deaths by 12 months between the 3 groups. Abbreviation: TR, tricuspid regurgitant.