Interobserver agreement on the echocardiographic parameters that estimate right ventricular systolic function in the early postoperative period of cardiac surgery

Abstract

Primary objective: To know the variability of transthoracic echocardiographic parameters that assess right ventricular systolic function by analyzing interobserver agreement in the early postoperative period of cardiovascular surgery.

Secondary objective: To assess the feasibility of these echocardiographic measurements.

Design: A cross-sectional study, double-blind pilot study was carried out from May 2011 to February 2013.

Setting: Cardiovascular postoperative critical care at the National Institute of Cardiology "Ignacio Chávez", Mexico City, Mexico.

Patients: Consecutive, non-probabilistic sampling. Fifty-six patients were studied in the postoperative period of cardiac surgery.

Intervention: The first echocardiographic parameters were obtained between 6-8hours after cardiac surgery, followed by blinded second measurements.

Main variables: Tricuspid annular plane systolic excursion (TAPSE), tricuspid annular peak systolic velocity on tissue Doppler imaging (VSPAT), diameters and right ventricular outflow area, tract fractional shortening. The agreement was analyzed by the Bland-Altman method, and its magnitude was assessed by the intraclass correlation coefficient (95% confidence interval).

Results: Both observers evaluated TAPSE and VSPAT in 48 patients (92%). The average TAPSE was 11.68±4.53mm (range 4-27mm). Right ventricular systolic dysfunction was observed in 41 cases (85%) and normal TAPSE in 7 patients (15%). The average difference and its limits according to TAPSE were -0.917±2.95 (-6.821, 4.988), with a magnitude of 0.725 (0.552, 0.837); the tricuspid annular peak systolic velocity on tissue Doppler imaging was -0.001±0.015 (-0.031, 0.030), and its magnitude 0.825 (0.708, 0.898), respectively.

Conclusions: VSPAT and TAPSE were estimated by both observers in 92% of the patients, these parameters exhibiting the lowest interobserver variability.

Keywords: Cardiac surgery; Cirugía cardiaca; Echocardiography; Ecocardiografía; Fiabilidad; Función del ventrículo derecho; Interobserver variability; Reliability; Right ventricular function; Variabilidad interobservador.