Correlation with hemodynamic measurements pre and post pulmonary endarterectomy.

Abstract

Purpose CT pulmonary angiography is commonly used in diagnosing chronic thromboembolic pulmonary hypertension (CTEPH) but its role in risk stratification is unknown. Hemodynamic thresholds of mean pulmonary artery pressure (mPAP) C 38 mm Hg and pulmonary vascular resistance (PVR)[5.3WU predict worse long-term survival post pulmonary thromboendarterectomy (PTE). This work was conducted to determine if cardiac chamber size on CTPA can predict adverse hemodynamics. Methods and Materials Retrospective analysis of paired CTPA and right heart hemodynamics in 33 consecutive CTEPH cases before and after PTE. Semiautomated and manual CT biatrial and biventricular size quantification were correlated with mPAP, PVR and cardiac output. Results Baseline indexed right atrioventricular volumes were twice left atrioventricular volumes with significant augmentation of left heart filling following PTE (P\0.001). Except for LA volume-cardiac index, all other chamber ratios significantly correlated (all p\0.05) with hemodynamics. Ventricular ratio cut-point\0.82 has high sensitivity (91% & 97%) and specificity (88% & 85%) for identifying significant elevation of mPAP and PVR respectively (AUC 0.90 & 0.95), outperforming atrial ratios (sensitivity 78% & 79%, specificity 82% & 92%, AUC 0.86 & 0.91). Manual LV:RV basal dimension ratio correlated strongly with semi-automated volume ratio (r 0.77, 95%CI 0.64-0.85, P\0.001) and is an expeditious alternative with comparable prognostic utility (AUC 0.90 & 0.95). Conclusion CTPA cardiac chamber size quantification in CTEPH provides non-invasive assessment of PH severity and can identify residual PH that may help triaging patients requiring close monitoring and alternate treatments. Ventricular measurements surpassed atrial metrics for outcome prediction.