Interobserver Reliability of Echocardiography in PE
Objectives: To evaluate the interobserver reliability of echocardiographic findings of right ventricle (RV) dysfunction for prognosticating normotensive patients with pulmonary embolism (PE).
Methods: A central panel of cardiologists evaluated echocardiographic studies of 75 patients included in the PROTECT study for the following signs: RV diameter, RV/left ventricular (LV) diameter ratio, hypokinesis of the RV free wall, and tricuspid plane systolic excursion (TAPSE). Investigators used intraclass correlation to assess agreement between the measurements of the central panel and each of the local cardiologists. Investigators used the single weighted kappa statistic to test for agreement between readers of interpretation of RV enlargement and RV hypokinesis.
Results: The two observers had fair agreement (k = 0.45) for RV enlargement assessed by the RV diameter, and good agreement (k = 0.65) for RV enlargement assessed by the RV/LV diameter ratio. The interobserver reliability of the assessment whether hypokinesis of the RV free wall is present was good (к = 0.70), and whether RV dysfunction (assessed by TAPSE measurement) is present was very good (k = 0.86). The intraclass correlation for the RV/LV diameter ratio was fair (0.55; 95% confidence interval [CI], 0.37–0.69), for the RV diameter was good (0.70; 95% CI, 0.56–0.80), and for the TAPSE measurement was very good (0.85; 95% CI, 0.77–0.90). On Bland-Altman analysis, the mean differences for RV diameter, RV/LV diameter ratio and TAPSE measurement were 2.33 (±5.38), 0.06 (±0.23) and 0.08 (±2.20), respectively.
Conclusion: TAPSE measurement is the least user dependent and most reproducible echocardiographic finding of RV dysfunction in normotensive patients with PE.
Acute pulmonary embolism (PE) is a common disease with a 3-month mortality rate of up to 17.4%. Even if PE is properly treated with anticoagulation, the mortality rate in hemodynamically stable patients varies from 8.1% to 15.1%. Death is usually caused by acute right heart failure. Acute PE increases the pressure of the pulmonary arterial system and right ventricle (RV) resulting in RV dysfunction, which may progress to right heart failure and circulatory collapse. Patients with RV dysfunction have a higher mortality rate than those without, even if they are initially hemodynamically stable. Thus, the presence of RV dysfunction is a marker for adverse clinical outcome in patients with acute PE.
Transthoracic echocardiography (TTE) is the most common first-line examination to diagnose the signs of RV dysfunction. Echocardiography is capable of visualizing the changes occurring in the morphology and function of the right ventricle as a result of acute pressure overload. A variety of different methods for the assessment of RV dysfunction on TTE have been proposed and the literature shows variable results for the prognostic power of TTE signs of RV dysfunction to predict adverse outcomes. This variability may in part be explained by the somewhat subjective nature of diagnosing RV dysfunction on TTE because formal criteria for establishing these signs are not available. It is noteworthy that prior publications on this topic did not report interobserver reproducibility of the findings.
Accordingly, the purpose of our study was to determine the interobserver reproducibility of TTE findings previously described to indicate RV dysfunction with the goal of identifying the most robust, least observer dependent method.
Abstract and Introduction
Abstract
Objectives: To evaluate the interobserver reliability of echocardiographic findings of right ventricle (RV) dysfunction for prognosticating normotensive patients with pulmonary embolism (PE).
Methods: A central panel of cardiologists evaluated echocardiographic studies of 75 patients included in the PROTECT study for the following signs: RV diameter, RV/left ventricular (LV) diameter ratio, hypokinesis of the RV free wall, and tricuspid plane systolic excursion (TAPSE). Investigators used intraclass correlation to assess agreement between the measurements of the central panel and each of the local cardiologists. Investigators used the single weighted kappa statistic to test for agreement between readers of interpretation of RV enlargement and RV hypokinesis.
Results: The two observers had fair agreement (k = 0.45) for RV enlargement assessed by the RV diameter, and good agreement (k = 0.65) for RV enlargement assessed by the RV/LV diameter ratio. The interobserver reliability of the assessment whether hypokinesis of the RV free wall is present was good (к = 0.70), and whether RV dysfunction (assessed by TAPSE measurement) is present was very good (k = 0.86). The intraclass correlation for the RV/LV diameter ratio was fair (0.55; 95% confidence interval [CI], 0.37–0.69), for the RV diameter was good (0.70; 95% CI, 0.56–0.80), and for the TAPSE measurement was very good (0.85; 95% CI, 0.77–0.90). On Bland-Altman analysis, the mean differences for RV diameter, RV/LV diameter ratio and TAPSE measurement were 2.33 (±5.38), 0.06 (±0.23) and 0.08 (±2.20), respectively.
Conclusion: TAPSE measurement is the least user dependent and most reproducible echocardiographic finding of RV dysfunction in normotensive patients with PE.
Introduction
Acute pulmonary embolism (PE) is a common disease with a 3-month mortality rate of up to 17.4%. Even if PE is properly treated with anticoagulation, the mortality rate in hemodynamically stable patients varies from 8.1% to 15.1%. Death is usually caused by acute right heart failure. Acute PE increases the pressure of the pulmonary arterial system and right ventricle (RV) resulting in RV dysfunction, which may progress to right heart failure and circulatory collapse. Patients with RV dysfunction have a higher mortality rate than those without, even if they are initially hemodynamically stable. Thus, the presence of RV dysfunction is a marker for adverse clinical outcome in patients with acute PE.
Transthoracic echocardiography (TTE) is the most common first-line examination to diagnose the signs of RV dysfunction. Echocardiography is capable of visualizing the changes occurring in the morphology and function of the right ventricle as a result of acute pressure overload. A variety of different methods for the assessment of RV dysfunction on TTE have been proposed and the literature shows variable results for the prognostic power of TTE signs of RV dysfunction to predict adverse outcomes. This variability may in part be explained by the somewhat subjective nature of diagnosing RV dysfunction on TTE because formal criteria for establishing these signs are not available. It is noteworthy that prior publications on this topic did not report interobserver reproducibility of the findings.
Accordingly, the purpose of our study was to determine the interobserver reproducibility of TTE findings previously described to indicate RV dysfunction with the goal of identifying the most robust, least observer dependent method.
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