Physical Exam Unreliable in Predicting Pulmonary Hypertension
While the majority of individuals suspected of having pulmonary hypertension would prefer to receive a physical examination to confirm diagnosis, invasive right heart catheterization may still offer the most reliable indication of diagnosis. “Utility of the Physical Examination in Detecting Pulmonary Hypertension: A Mixed Methods Study,” published in PLOS One by a team from the University of Toronto and Hamilton General Hospital in Canada, revealed that while a few metrics determined through physical examination may be associated with pulmonary hypertension, their use in detecting pulmonary hypertension in unreliable.
After identifying a handful of factors that should be assessed during physical examination–right ventricular lift, loud P2 (pulmonic valve closure heart sound), jugular venous distension, tricuspid insufficiency murmur, and right-sided heart sound at rest and during a slow inspiration–the researchers assigned patients to be examined by six physicians, three of whom were specialists and three of whom were generalists. Beforehand, patients underwent right heart catheterization, but physicians were blinded to the resultant diagnosis. Following physical examination of patients, physicians assigned a score of 1-5 to indicate the likelihood of existing pulmonary hypertension.
Upon comparing actual and predicted diagnoses, the researchers found loud P2 on inspiration to have the highest likelihood ratio. This is consistent with previous literature identifying the loud component of the second heart sound (P2) as highly associated with pulmonary hypertension. Considering only results from specialist examiners, loud P2 on inspiration had a likelihood ratio of 3.2, and right sided S4 heart sound (a “gallop” of blood rushing into a stiff ventricle) had a likelihood ratio of 4.7. Although specialist examiners had a higher utility of physical examination for diagnosing pulmonary hypertension than did generalists, there was no factor that reliably ruled out pulmonary hypertension, limiting the use of physical examination.
Since all patients recruited for the study had received prior right heart catheterization, there was already a potential indication for heart trouble. This may have affected the results of the study, and it may be interesting to determine the utility of physical examination when applied to the general population or to individuals with conditions such as scleroderma, which increases the risk for developing pulmonary hypertension.