Page 187 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

Summary
Pulmonary arterial hypertension is characterized by remodeling of the small pulmonary arteries leading to an increase in resistance of the pulmonary vascular bed and an increase in pulmonary artery pressures. The vascular remodeling comprises several features. The lumen of the vessels is narrowed because of vasoconstriction, hyperproliferation of smooth muscle cells and endothelial cells, inflammation and several other aspects. The increase in resistance increases the load on the right ventricle.
Initially, the right ventricle will try to adapt to the increase in pressures and subsequent rise in wall stress through a complex interplay of ventricular remodeling, neuro-hormonal activation and changes in myocardial metabolism. Simplified, the first step in the process of remodeling is right ventricular hypertrophy and an increase in contractility. If, despite these adaptive changes, cardiac output cannot be maintained, the right ventricle will dilate further increasing wall stress. Finally, right ventricular failure will occur, which is the main cause of death in pulmonary arterial hypertension. In this thesis, a number of techniques and methods were evaluated that may contribute to earlier recognition of PAH and improved monitoring and prognostication.
Early recognition and prognostication in pulmonary hypertension
Due to the non-specific nature of symptoms at presentation, most patients with pulmonary arterial hypertension are diagnosed by the time their disease is in an advanced stage. It has been shown that early detection of PH and a timely initiation of treatment can significantly improve the clinical outcome. Computed tomography pulmonary angiography (CTPA) is a diagnostic tool often used in the diagnostic process of patients that present with unexplained dyspnea, for example to exclude pulmonary emboli. Such scans can already reveal clues for the presence of pulmonary hypertension. A well-known clue for the presence of pulmonary hypertension is an increased ratio between the diameter of the pulmonary artery and the diameter of the ascending aorta. In chapter 2, we investigated whether the predictive value of CTPA for the presence of pulmonary hypertension could be improved by combining this measurement with the diameter ratio of the right ventricle and left ventricle. We found that the predictive value of CTPA for precapillary pulmonary hypertension improved when ventricular and pulmonary artery measurements were combined.
The prognostic value of right ventricular parameters in pulmonary hypertension is well-established. Whether a combination of parameters of the right heart merged into a risk score predict outcome in
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