Abstract
Background and Aims
Patients with chronic kidney disease (CKD) are characterized by higher cardiovascular risk resulting amongst others from fluid expansion. Lung water measured by ultrasound (US) technique is increasingly recognised as an effective, quick and objective technique of even subclinical congestion/fluid overload. We aim to search correlates between the amount of artifact b-lines in lungs ultrasound (US-B lines; a metric of lung water), intra- and extracellular water (ICW, ECW), arterial stiffness by pulse wave velocity, result of functional six minute walk tests (6MWT) and global longitudinal strain score (GLS) assessed during heart ultrasound in patients with preserved ejection fraction.
Method
ICW/ ECW was assessed by bioimpedance (BIA 101 Akern), pulse wave velocity (PWV) by oscillometric method (mobilograph, IEM Germany). GLS was calculated using 2-dimensional speckle tracking. Traditional biochemical cardiac and renal markers and inflammatory markers were also assessed.
Results
The study included 51 consecutive patients (34 male) with CKD stage 4 and 5 (median eGFR MDRD4 11 ml/min IQR 9; 17) with oligosymptomatic congestion. The median (IQR) EF was 60 (60; 65)%, GLS was -18,7 (-21; -14)%, US-B lines was 10,5 (6; 17). Factors that were associated with US-B lines include BNP (r 0,5), ECW (r 0,4), distance in 6MWT (r –0,48) and hemoglobin (r -0,37).
In comparison between groups (below vs above median) with more lung water (>11 US-B lines) and less lung water amount (<11) assessed after 5 min in a supine position we found markedly higher concentration of BNP and more extracellular water (ECW) in the first mentioned group (table). Patients with more B-lines have had lower hemoglobin level and shorter distance walked in 6MWT.
Conclusion
Lung water assessed by US is an quick and objective measure of congestion in advanced CKD with normal EF showing correlation with BNP concentration, distance walked in 6MWT and with extracellular water in bioimpedance. Its application into daily practice can be recommended.
MEASUREMENT OF AORTIC PULSE WAVE VELOCITY IN PATIENTS WITH SUBCLINICAL OR CLINICAL HEART FAILURE WITH PRESERVED EJECTION FRACTION
