Non-invasive measurement of right atrial pressure by near-infrared spectroscopy. preliminary experience. a report from the SICA-HF study

Aims: To assess the clinical value of measuring right atrial pressure (RAP) using near-infrared spectroscopy (NIRS) in patients with chronic heart failure (CHF). Methods and results: RAP was measured non-invasively using NIRS over the external jugular vein (Venus 1000, Mespere LifeSciences, Canada) in ambulatory patients with CHF enrolled in the Studies Investigating Co-morbidities Aggravating HeartFailure (SICA-HF) programme. Comparing 243 patients with CHF (mean age 71 years; mean left ventricular ejectionfraction (LVEF) 45%, median NT-proBNP 788 ng/L) to 49 controls (NT-proBNP ≤125 ng/L), RAP was 7 [interquartile range (IQR) 4–11] mmHg vs. 4 (IQR 3–8) mmHg (P < 0.001). Those with RAP ≥10 mmHg (n = 75) were older, had more severe clinical congestion and renal dysfunction, higher plasma NT-proBNP, larger left atrial volume, higher systolic pulmonary pressure and were more often in atrial fibrillation but their LVEF was similar to patients with lower RAP. During a median follow-up of 595 (IQR: 492–714) days, 49 patients (20%) died or were hospitalized for worsening CHF. Compared with patients with RAP ≤5 mmHg, those with RAP ≥10 mmHg had a greater risk of an event (hazard ratio 2.38, 95% confidence interval 1.19–4.75, P = 0.014). RAP measured by NIRS predicted outcome, competing with NT-proBNP in multivariable models. Conclusions: Measuring RAP using NIRS identifies ambulatory patients with CHF who have more severe congestion and a worse outcome. The device might be a useful objective method of monitoring RAP, especially for those inexperienced in eliciting physical signs or when measurement of natriuretic peptides is not immediately available.