Doppler Recognition of Low or Normal Central Venous Pressure from Continuous Flow from Inferior Vena Cava Into Right Atrium.

Estimation of right atrial (RA) or central venous pressure (CVP) is a critical component of a comprehensive transthoracic echocardiographic (TTE) examination. We hypothesize that continuous inflow from the inferior vena cava (IVC) into the RA is a surrogate for low/normal CVP and can be reliably imaged in standard echocardiographic parasternal short and right ventricular inflow views. We retrospectively studied 200 patients who underwent right heart catheterization (RHC) within 8 hours of TTE between 2012 and 2016, and selected 60 patients in whom the continuous wave Doppler beam incidentally interrogated IVC inflow into RA during evaluation of the tricuspid valve. From these studies, we sought an uninterrupted Doppler wave (DW) inflow signal. CVP on RHC were then compared in patients with continuous and interrupted DW. Other TTE and RHC parameters were also noted and compared in these 2 groups. The average time interval between TTE and RHC was 266 ± 151 minutes. Of 60 patients (males = 39 (65%); age 63 ± 14 years), 12 patients (20%) had continuous DW and 48 (80%) had interrupted DW inflow signal from IVC into the RA. Of the 12 patients with continuous flow, 11 had RA pressure of ≤7 mm Hg. Similarly, of 48 patients with interrupted flow, RA pressure was >7 mm Hg in 45, and less than ≤7 mm Hg in 3 patients (two-sided p value 0.0001). The continuous DW signal predicted RA of ≤7 mm Hg with a sensitivity and specificity of 98% and 78%, respectively. Additionally, when combined with IVC size and collapsibility (normal-sized collapsible IVC), the sensitivity and specificity of DW signal to predict RA of ≤ 7 mmHg were enhanced to 94% and 92%, respectively. In conclusion, IVC flow pattern can be reliably studied to estimate CVP in standard echocardiographic views. Continuous and interrupted IVC flow predicts normal and elevated RA pressure, respectively.