Page 37 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

Recognizing the signs of pulmonary hypertension on CTPA provides the radiologist with a tool to identify the disease timely. CTPA is often performed early in the diagnostic process of patients with unexplained dyspnea. Combining ventricular and pulmonary artery measurements decreases the chance that the diagnosis of precapillary PH is missed. When there is suspicion of precapillary PH, and a CTPA is made, we recommend radiologists to assess not only the diameters of the great vessels, but also of both ventricles. When the PA/AA-ratio is greater or equal to 1 or when the RV/LV is greater or equal to 1.20, further diagnostic tests, to confirm or rule out PH are required. As a next diagnostic step, we would recommend to perform an echocardiography.
We want to emphasize, that CTPA measurements should not be used as a primary screening tool for precapillary PH. In isolation, CTPA measurements are not suitable to rule out or confirm the diagnosis of precapillary PH.
The reason for including patients with idiopathic pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension in this analysis is that a timely diagnosis in these conditions can be lifesaving. Whether or not our results can be extrapolated to other forms of precapillary PH for which no treatment is currently available requires further investigations. In addition, we excluded patients with PH due to left sided systolic or diastolic heart failure (WHO group 2). That this may not be a major problem is suggested by the study of Chan et al. *16+, in which mostly WHO group 2 PH patients were included and PA/AAAX and RV/LVAX, measured separately, were good predictors of PH.
Study limitations
First of all, baseline hemodynamic results suggested that all our PH patients were diagnosed in an advanced stage of their disease. We do not know whether our findings can be extrapolated to the earliest stages of the disease. Another limitation is that we performed a retrospective analysis. Preferably, a prospective analysis would be performed in a general population undergoing a CTPA for the evaluation of dyspnea. However, performing such a study would be very difficult regarding the low prevalence of precapillary PH.
18 CTPA studies were performed on a 4-slice CT system. Theoretically, on a 4-slice CT system, not all slices depicting the heart are in the same phase of the cardiac cycle. However, since the slices depicting the maximum diameter of the RV and LV were mostly adjacent or very close to each other, we did no experienced this problem.
Chapter 2
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