Inferior vena cava contrast reflux grade is associated with a reduced cardiac index in acute pulmonary embolism

Background and Aims

Patients with intermediate-risk pulmonary embolism (PE) commonly present with a significantly reduced cardiac index (CI). However, the identification of this more severe profile requires invasive hemodynamic monitoring. Whether inferior vena cava (IVC) contrast reflux, as a marker of worse right ventricular function, can predict invasive hemodynamics has not been explored.

Methods

This was a single-center retrospective study over a 3-year period of consecutive patients with PE undergoing mechanical thrombectomy and simultaneous pulmonary artery catheterization. CT pulmonary angiograms were reviewed, and contrast reflux was graded as no/minimal reflux (limited to the IVC) or substantial (opacification including hepatic veins) based on an established scale.

Results

Substantial contrast reflux was present in 29 of 85 patients (34 %) and associated with a lower CI (1.8 ± 0.4 L/min/m² v. 2.6 ± 1.0 L/min/m², p < 0.001), higher pulmonary artery systolic pressure (53.2 ± 19.5 mmHg v. 44.0 ± 12.1 mmHg, p = 0.025), and worse right ventricular systolic function. An IVC contrast reflux grade > 3 was a significant predictor for a CI ≤2.2 L/min/m² (OR: 22.5, 95 % CI: 4.8, 104.4, p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for substantial contrast reflux for a CI ≤2.2 L/min/m² were 62.6 %, 93.1 %, 94.6 %, and 56.2 %, respectively. These findings remained significant in a multivariable model and were similar when isolating for intermediate-risk patients (n = 72, 85 %).

Conclusions

The degree of contrast reflux is highly specific for a reduced cardiac index in PE even when isolating for intermediate-risk patients. Real-time prediction of a hemodynamic profile may have added value in the risk-stratification of PE.