Evaluation of Echocardiographic Indices and Blood Biomarkers in Group 1 Pulmonary Hypertension

Overview

* To evaluate different echocardiographic indices in diagnosis and follow up of group 1 pulmonary hypertension. * To evaluate blood biomarkers (troponin, uric acid and micro RNA) in naïve group 1 pulmonary hypertension.

Introduction: Pulmonary hypertension is pathophysiological condition defined as increases of mean pulmonary artery pressure above 20 mmHg as assessed by right heart catheterization (RHC) (1). As pulmonary hypertension has a variety of causes with different clinical presentations and characteristics; it is classified into five clinical groups (2): * Group 1 and also called pulmonary arterial hypertension group. * Group 2 due to left sided heart diseases. * Group 3 caused by chronic lung diseases and hypoxemia. * Group 4 caused by chronic pulmonary artery occlusions. * Group 5 that has unclear and multifactorial causes. Although group 1 less common; it is carrying significant clinical importance as early detection can improve the patient's outcome through providing them the available vasodilator medications. To diagnose patient in group 1 PH, the patient should have RHC (3) to obtain the definite hemodynamic before starting treatment as advised by PH guidelines, however RHC is invasive and expensive procedure and carrying some bad drawback (4). Transthoracic echocardiography is less expensive, non-invasive and nonhazardous procedure and commonly provide significant parameters before RHC (5). several echocardiographic indices correlate significantly with RHC hemodynamic, as peak tricuspid regurgitation velocity , right ventricular outflow acceleration time, peak early pulmonary regurgitation velocity , peak late pulmonary regurgitation velocity, tricuspid regurgitation time velocity integral ,and tricuspid annulus tissue Doppler image velocities. Most of these parameters used individually to echocardiographic diagnose PH, however little data available to integrate them together to echocardiographic diagnose PH in group1; integrations of theses parameters might improve PH diagnosis As pulmonary arterial hypertension is Patho biological disease, and affecting small pulmonary arteries and arterioles, the pathologic pattern of vascular lesions is characterized by intimal hyperplasia, medial thickness, plexiform lesions, and thrombosis in situ, and is caused by increased migration and proliferation of smooth muscle cells (SMCs) and adventitial fibroblasts, abnormal endothelial cell proliferation, and impaired apoptosis (6). several biomarkers play significant role in pathogenesis and prognosis of the diseases, serum uric acid (7,8) and serum troponin (9) may increase in PH and may affecting the clinical severity however further studies needed to confirm this . Also micro RNA new marker of assessing cardiovascular diseases , may have role in assessing group 1 pulmonary hypertension(10).

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