Inferior vena cava diameter adds information to pulmonary artery systolic pressure in outpatients with heart failure

Abstract

Abstract Background Evaluation of pulmonary arterial pressure (PAP) is recommended by guidelines to diagnose and monitor congestion in patients with heart failure (HF). However, the high compliance of the venous system might buffer the effects of a large increase in intravascular volume and delay an elevation in PAP. Therefore, measuring inferior vena cava (IVC) diameter by ultrasounds might add important information in patients with HF, regardless of PAP. Aim To evaluate the relationship between the IVC diameter and systolic PAP (PAsP) assessed by echocardiography with mortality in outpatients with HF. Methods We enrolled consenting out-patients attending a community HF clinic for initial diagnosis or follow-up in Kingston upon Hull, UK between 2009–2012. HF was defined as the presence of relevant symptoms and signs and objective evidence of cardiac dysfunction: either a left ventricular systolic function (LVEF) <50% or elevated amino-terminal pro-brain natriuretic peptide (NT-proBNP) ≥125 pg/ml. IVC was considered dilated when >2.0 cm, PAsP elevated when >35 mmHg. Results Amongst the 874 patients enrolled, median age was 75 years, 68% were men, median LVEF was 44% and median NT-proBNP was 1125 pg/ml. 468 patients (54%) had normal IVC and PAsP, 117 (13%) had normal IVC but elevated PAsP, 75 (8%) had dilated IVC but normal PAsP and 214 (25%) had both dilated IVC and elevated PAsP. Compared to those with normal IVC and PAsP, those with elevated PAsP but normal IVC were older, more likely to be women, and had higher LVEF and NT-proBNP, whilst those with dilated IVC but normal PAsP had similar age and LVEF, but more signs of congestion and higher NT-proBNP. Compared to those with both normal IVC and PAsP (reference), those with dilated IVC but normal PAsP (HR: 1.83; CI: 1.04–3.25; P=0.037) or elevated PAsP but normal IVC (HR: 1.88; CI: 1.25–2.85; P=0.003) had a similarly increased risk of death but those with a dilated IVC and elevated PAsP had the greatest risk (HR: 4.16; CI: 3.10–5.57; P<0.001). Conclusion A dilated IVC is associated with mortality even when PAsP is not elevated. Tailoring treatments to reduce IVC diameter is a strategy worth exploring to improve outcomes in outpatients with heart failure. Funding Acknowledgement Type of funding sources: None.