Estimation of right atrial and ventricular hemodynamics by CT coronary angiography

Background: Computed tomography coronary angiography (CTCA) provides an accurate noninvasive alternative to the invasive assessment of coronary artery disease. However, a specific limitation of CTCA is inability to assess hemodynamic data. Objective: We hypothesized that CTCA-derived measurements of contrast within the superior vena cava (SVC) and inferior vena cava (IVC) would correlate to echocardiographic estimations of right atrial and right ventricular pressures. Methods: Medical records of all patients who underwent both echocardiography and CTCA in our center were reviewed (n = 32). Standard CTCA was performed with a 64-detector CT using test-bolus method for image acquisition timing and iso-osmolar contrast injection through upper extremity vein. The length of the column of contrast reflux into the inferior vena cava (IVC) was correlated to echocardiographically determine tricuspid regurgitation jet velocity (TRV). SVC area change with contrast injection at the level of the bifurcation of the pulmonary artery was also correlated with IVC sniff response by echocardiogram. Results: The reflux column length was interpretable in 27 of 32 patients with a mean length of 10.1 ± 1.1 mm, and a significant bivariate correlation was observed between reflux column length and the tricuspid regurgitant jet velocity (r = 0.84; P < .0001). Mean SVC distensibility ratio was 0.63 ± 0.03; mean IVC sniff response ratio was 0.53 ± 0.03. SVC distensibility correlated to IVC sniff response with a Pearson r of 0.57 (P = .04). Conclusion: Quantification of IVC and SVC contrast characteristics during CTCA provides a feasible and potentially accurate method of estimating right atrial and ventricular pressure.