Conference: 2014 International PHA Conference and Scientific Sessions
Release Date: 06.21.2014
Presentation Type: Abstracts
Background: Many patients who undergo computerized tomographic pulmonary angiography (CTPA) have persistent symptoms including dyspnea, leading to repeat CTPA scanning. Right ventricular (RV) dysfunction is commonly unrecognized in patients with shortness of breath, yet can signal treatable causes of dyspnea. We hypothesized that a substantial proportion of patients with negative CTPA have unrecognized RV dysfunction. We report the rate of isolated RV dysfunction after CTPA and develop criteria that would predict RV dysfunction on echocardiography after negative CTPA.
Methods: This was a secondary analysis of a prospective, multicenter study of diagnostic accuracy for pulmonary embolism (PE). Inclusion required persistent dyspnea and no diagnosis of PE. Echocardiography was ordered at clinician discretion, performed within one week of enrollment. Isolated RV dysfunction required normal left ventricular function and RV hypokinesis, moderate-severe tricuspid regurgitation or estimated RV systolic pressure ≥ 40 mm Hg. The clinical decision rule was derived from bivariate analysis of 100 candidate variables, then multivariate logistic regression. To assess if RV dysfunction led to symptoms that prompted re-evaluation, we compared the frequency of repeat CTPA within 90 days.
Results:647 patients were enrolled; 120 were excluded due to a diagnosis of PE, and 97 were excluded because of lack of persistent dyspnea. Of the 430 remaining patients, 184 underwent echocardiography, which demonstrated isolated RV dysfunction in 34% (95% CI: 30-41%). 27% of patients with isolated RV dysfunction had repeat CTPA within 90 days, a significantly higher rate than in patients without echo (4%, P=0.03, Chi Square) or a normal echo (5%, P=0.02). Four variables predicted isolated RV dysfunction (complete right bundle branch block, normal CTPA scan, active malignancy, and CTPA with infiltrate; the latter negatively predicted). Logistic regression found only normal CTPA as a significant predictor of RV dysfunction (P<0.05). The final rule (persistent dyspnea + normal CTPA scan) had a positive predictive value of 53% (95% CI 37-69%).
Conclusion: A simple clinical decision rule, consisting of persistent dyspnea plus a normal CTPA scan predicts a high probability of isolated RV dysfunction on echocardiography. Patients with isolated RV dysfunction are more likely to have repeated non-diagnostic CTPA scanning in the short term. These findings can form the starting point for a screening protocol to select patients with negative CTPA scanning for formal echocardiography and subsequent specialist referral to evaluate for potential pulmonary hypertension or other treatable causes of RV dysfunction.
Type: Clinical Science