Lung Congestion as a Risk Factor in End-Stage Renal Disease

Abstract

Background: Lung congestion is emerging as a pervasive, insidious problem in end-stage renal disease (ESRD) patients on dialysis. Summary: Chest ultrasound (US), a novel, easy-to-perform, cheap technique, which is currently applied for objective monitoring of pulmonary congestion in patients with heart failure in Europe, allows reliable quantification of lung water in clinical practice. Before hemodialysis (HD), about 60% of ESRD patients displayed moderate-severe lung congestion and this alteration is frequently asymptomatic. Lung congestion is reduced but not abolished by ultrafiltration dialysis, and about one third to one fourth of patients still have excessive lung water after dialysis. Lung congestion is also prevalent in patients on peritoneal dialysis (PD), and in apparently asymptomatic HD and PD patients this alteration is strongly associated with poor physical performance. Lung water in HD patients correlates in an inverse fashion with echocardiographic parameters of systolic and diastolic function, but it is only weakly related with hydration status measured by bioimpedance analysis. Moderate-severe lung congestion is a strong predictor of death and cardiovascular events and provides prognostic information independent of NYHA class, and traditional and nontraditional risk factors in ESRD patients on HD. Key Messages: Systematic application of chest US in ESRD patients shows that hidden or clinically manifest lung congestion is exceedingly frequent in this population. This alteration largely reflects left ventricular disorders superimposed on volume overload. The clinical usefulness of systematic application of chest US in ESRD remains to be tested in a formal clinical trial.

Relevance of B-Lines on Lung Ultrasound in Volume Overload and Pulmonary Congestion: Clinical Correlations and Outcomes in Patients on Hemodialysis

“…The challenge of reaching and maintaining euvolemia is more difficult, especially in patients with cardiomyopathy and hemodynamic frailty. The detection of mild to moderate degrees of volume overload is one of the main quests that challenges clinicians, considering symptoms that may be attributed to other prevalent comorbidities in ESRD patients [17,18,19]. …”

“…Chest ultrasound helps detecting lung congestion among ESRD patients on HD, even at its early stage when clinically asymptomatic. The prognostic value of total extracellular body water has been clearly demonstrated to be the most relevant finding, in predicting clinical outcomes, the risk of death and cardiovascular events independent of the NYHA score, and classical risk factors in patients with heart disease [17]. It surpasses the overall hydration status, inflammation (assessed by C-reactive protein), and cardiac parameters in predicting the risk of death and cardiac events.…”

“…This fact highlights the predominant effect of volume overload in our study population. Pulmonary congestion is not always related to high left ventricular filling pressure, and can be partly explained by increased total body water or volume redistribution, indicating that B-lines describe a water compartmental redistribution [17]. …”

“…In addition to volume overload, ESRD patients were observed to have altered lung permeability secondary to intrinsic lung alterations triggered by dialysis membranes or uremic symptoms putting this population at high risk for cardiopulmonary complications. [17]. …”

“…The investigators visualized a total of 28 anatomical points on the subjects' chest as validated by Zoccali et al [17] and approved internationally as a general consensus [7,17]. Twenty-eight different lung windows were scanned in the midaxillary, anterior axillary, midclavicular, and parasternal spaces: 16 windows on the right hemithorax in the 2nd through 5th intercostal spaces and 12 on the left hemithorax in the 2nd through 4th intercostal spaces.…”