Pulmonary hypertension · Estimating pulmonary pressures non-invasively
Echocardiographic assessment of pulmonary hypertension in patients with advanced lung disease
| Design | Cohort study with right heart catheterisation as reference standard |
|---|---|
| Treatment | Doppler echocardiographic estimate of systolic pulmonary artery pressure |
| Control | Right heart catheterisation |
| Population | 374 lung transplant candidates with advanced lung disease |
| Follow-up | Diagnostic study |
| Primary endpoint | Accuracy of echocardiographic pressure estimation against catheterisation |
| Result | Pressure estimation was possible in only 166 patients (44%). Correlation with catheterisation was good (r=0.69, p<0.0001), but 52% of estimates were inaccurate by more than 10 mmHg and 48% of patients were misclassified as having pulmonary hypertension. Sensitivity 85%, specificity 55%, positive predictive value 52%, negative predictive value 87%. |
| Secondary endpoints | Proportion in whom estimation was feasible, direction of misclassification |
Despite a statistically significant correlation with directly measured values, estimation of systolic pulmonary artery pressure by echocardiography is frequently inaccurate in patients with advanced lung disease and leads to considerable overdiagnosis of pulmonary hypertension.
The trial authors, in the published abstract
A correlation of 0.69 sounds respectable and conceals a 52% positive predictive value. This is why pulmonary hypertension is not diagnosed on echocardiography, and why the negative predictive value of 87% is the number actually worth using — echo is a reasonable rule-out and a poor rule-in. Fisher 2009 found the same in a general PH population.
Arcasoy SM, Christie JD, Ferrari VA, et al. Echocardiographic assessment of pulmonary hypertension in patients with advanced lung disease. Am J Respir Crit Care Med 2003 Mar 1;167(5):735-40.