Accuracy of chest radiography in predicting pulmonary hypertension: A case-control study

Objective

To assess the accuracy of chest radiography (CXR) in predicting pulmonary hypertension (PH).

Methods

We studied 108 consecutive patients with suspected PH who underwent right heart catheterization (RHC). All were PH treatment naives. Hemodynamic criteria included a mean pulmonary artery pressure > 25 mmHg at rest, and a mean pulmonary wedge pressure < 15 mmHg. Postero-anterior and lateral CXR were obtained shortly before RHC. To avoid a selection bias which could be introduced by examining only patients with suspected PH, we included in the analysis the CXR of 454 additional patients with different diagnosis: 57 with left heart failure (LHF) and pulmonary venous hypertension at RHC, 197 with chronic obstructive pulmonary disease, and 200 non-obstructed controls. CXR were examined independently by 4 raters, who were blinded to clinical, hemodynamic, and spirometric data. The diagnosis of PH was made if a prominent main pulmonary artery was associated with anyone of: isolated enlargement of right ventricle, right descending pulmonary artery > 16 mm in diameter, pruning of peripheral pulmonary vessels.

Results

Eighty-two patients had PH confirmed at RHC. Weighted sensitivity of CXR was 96.9% (95% confidence interval, 94.9 to 98.2%), and weighted specificity 99.8% (95% confidence interval, 99.6 to 99.9%). By considering the 165 patients who underwent RHC, weighted sensitivity of CXR was unchanged, and weighted specificity decreased to 99.1%. None of the patients with PH were misclassified as having LHF, and vice versa.

Conclusions

CXR is accurate in predicting PH. It may aid clinicians in selecting patients with suspected PH for hemodynamic ascertainment.