Femoral venous stasis index predicts elevated right atrial pressure and mortality in pulmonary hypertension

Background Elevated right atrial pressure (RAP) is associated with poor prognosis regarding 1-year mortality in pulmonary hypertension (PH) patients. Unfortunately, there is currently no reliable non-invasive technique for estimating RAP in PH patients. Recently, femoral venous stasis index (FVSI) has been described as highly correlated with RAP in PH patients. Our main goal was to confirm the diagnostic accuracy of FVSI for estimating RAP. Methods In this prospective study, we included 101 patients with suspected or known PH undergoing right heart catheterisation for 18 months. Results FVSI was highly correlated with RAP (r s =0.77, p<0.001). With a cut-off of 0.18, FVSI can exclude RAP >8 mmHg with 89% sensitivity (area under the receiver operating characteristic curve (AUROC) 0.88) and, with a cut-off of 0.45, can confirm RAP >14 mmHg with 93% specificity (AUROC 0.93). During a 2-year follow-up, the composite end-point (hospitalisation, increase in PH treatment and all-cause death) occurred in 32 patients (31.7%). FVSI predicted PH morbidity/mortality (FVSI ≥0.45 versus <0.18: HR 8.37 (95% CI 2.84–24.7); p<0.001). Inter-observer reproducibility between junior and senior operators was excellent (intraclass correlation coefficient 0.97 (95% CI 0.95–0.98)). Conclusion We propose FVSI as a rapid, simple, non-invasive tool for estimating RAP and which may be of additional prognostic interest in terms of PH-related morbi-mortality.