Detection of pulmonary congestion by chest ultrasound in dialysis patients.

OBJECTIVES

This study sought to investigate clinical and echocardiographic correlates of the lung comets score.

BACKGROUND

Early detection of pulmonary congestion is a fundamental goal for the prevention of congestive heart failure in high-risk patients.

METHODS

We undertook an inclusive survey by a validated ultrasound (US) technique in a hemodialysis center to estimate the prevalence of pulmonary congestion and its reversibility after dialysis in a population of 75 hemodialysis patients.

RESULTS

Chest US examinations were successfully completed in all patients (N = 75). Before dialysis, 47 patients (63%) exhibited moderate to severe lung congestion. This alteration was commonly observed in patients with heart failure but also in the majority of asymptomatic (32 of 56, 57%) and normohydrated (19 of 38, 50%) patients. Lung water excess was unrelated with hydration status but it was strongly associated with New York Heart Association functional class (p < 0.0001), left ventricular ejection fraction (r = -0.55, p < 0.001), early filling to early diastolic mitral annular velocity (r = 0.48, p < 0.001), left atrial volume (r = 0.39, p = 0.001), and pulmonary pressure (r = 0.36, p = 0.002). Lung water reduced after dialysis, but 23 patients (31%) still had pulmonary congestion of moderate to severe degree. Lung water after dialysis maintained a strong association with left ventricular ejection fraction (r = -0.59, p < 0.001), left atrial volume (r = 0.30, p = 0.01), and pulmonary pressure (r = 0.32, p = 0.006) denoting the critical role of cardiac performance in the control of this water compartment in end-stage renal disease. In a multiple regression model including traditional and nontraditional risk factors only left ventricular ejection fraction maintained an independent link with lung water excess (beta = -0.61, p < 0.001). Repeatability studies of the chest US technique (Bland-Altman plots) showed good interobserver and inter-US probes reproducibility.

CONCLUSIONS

Pulmonary congestion is highly prevalent in symptomatic (New York Heart Association functional class III to IV) and asymptomatic dialysis patients. Chest ultrasound is a reliable technique that detects pulmonary congestion at a pre-clinical stage in end-stage renal disease.