Right Ventricular-Pulmonary Arterial Uncoupling as a Predictor of Invasive Hemodynamics and Normotensive Shock in Acute Pulmonary Embolism

Abstract

Right ventricular-pulmonary arterial coupling describes the relation between right ventricular contractility and its afterload and is estimated as the ratio of the tricuspid annular plane systolic excursion (TAPSE) to pulmonary arterial systolic pressure (PASP) by way of echocardiography. Whether TAPSE/PASP is reflective of invasive hemodynamics or occult shock in acute pulmonary embolism (PE) is unknown. This was a single-center retrospective study over a 3-year period of consecutive patients with PE who underwent mechanical thrombectomy and simultaneous pulmonary artery catheterization with echocardiograms performed within 24 hours before the procedure. A total of 70 patients (81% intermediate risk) had complete invasive hemodynamic profiles and echocardiograms, with TAPSE/PASP calculated. The optimal cutoff for TAPSE/PASP as a predictor of a reduced cardiac index (CI) (CI ≤2.2 L/min/m²) was 0.34 mm/mm Hg, with an area under the curve of 0.97 and sensitivity, specificity, positive predictive value, and negative predictive value of 97.3%, 90.9%, 92.3%, and 96.8%, respectively. Every 0.1 mm/mm Hg decrease in TAPSE/PASP was associated with a 0.24-L/min/m² decrease in the CI. This relation was similar when restricted to intermediate-risk PE. The TAPSE/PASP ratio was predictive of normotensive shock with an odds ratio of 2.63 (95% confidence interval 1.42 to 4.76, p = 0.002) per unit decrease in the ratio. In conclusion, in patients with acute PE who underwent mechanical thrombectomy, TAPSE/PASP was a strong predictor of a reduced CI and normotensive shock. This means that noninvasive point-of-care assessment of hemodynamics may have added value in PE risk stratification.

Keywords: RV hemodynamics; RV-PA coupling; TAPSE/PASP; normotensive shock; pulmonary embolism; right ventricular failure.