Page 25 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

Introduction
Pulmonary hypertension (PH) is defined as an increase in mean pulmonary artery pressure (mPAP) above 25 mmHg [1]. Irrespective of the exact cause, the condition leads to right heart failure and finally death [2].
Most PH patients are diagnosed by the time their disease is in an advanced stage [3, 4]. The non- specific nature of symptoms at presentation (exercise-induced dyspnea, fatigue) leads to failure of physicians to recognize the disease and an undesirable late diagnosis. [4-7]. Early detection of PH and a timely initiation of treatment can significantly improve the clinical outcome [8-10]. A unique opportunity for an earlier diagnosis of PH is provided when a standard non-ECG gated computed tomography pulmonary angiography (CTPA) is performed to evaluate a patient presenting with shortness of breath. To the attentive radiologist, CTPA may provide important clues towards a diagnosis of PH.
An intensively studied feature to predict PH on CTPA is an increased diameter ratio of the pulmonary artery (PA) to ascending aorta (AA) [11-17]. Studies showed that this parameter has a sensitivity of 58-87% for the diagnosis of PH. A way to improve the diagnostic sensitivity is to add information on the structure of the heart.
The clinical value of the ratio of the transverse diameter of the right ventricle (RV) and the left ventricle (LV) measured on the axial (AX) view and on a manually reconstructed four chamber (4CH) view is known as a typical sign of RV failure in acute pulmonary embolism [18, 19]. One study measured the RV/LV diameter ratio on the axial view in mainly post-capillary PH patients and found a sensitivity of 86% [16]. It is unknown whether adding ventricular measurements to the PA/AA-ratio improves the diagnostic model of CTPA for precapillary PH.
Therefore, the aim of our study is to investigate whether combining PA measurements with ventricular measurements improves the predictive value of CTPA for precapillary PH.
Methods
Study subjects
The PH center in the VU University Medical Center is a tertiary referral center for pulmonary hypertension patients in the Netherlands. From a large database of subjects who had been referred to the VU University Medical Center from 2002 through 2012 for the evaluation of pulmonary hypertension, we retrospectively, randomly selected treatment naïve precapillary PH patients. Only
Chapter 2
23
2