Differentiate Pulmonary arterial hypertension from pulmonary venous congestion

Pulmonary Arterial Hypertension Causes – Primary/ Idiopathic Genetic – Secondary Cardiac Pulmonary 1.hypoxic vasoconstriction 2.decreased area of the pulmonary vascular bed 3.volume/pressure overload

Secondary Pulmonary Arterial Hypertension Hypoxic Vasoconstriction – COPD and obstructive sleep apnea – Due to down regulation of endothelial nitric oxide synthetase Decreased Area of Pulmonary Bed – Occurs when loss of vessels exceed 60% of the total pulmonary vasculature – Occurs in patients with collagen vascular disease like CREST and scleroderma. And those with chronic emboli

Volume/ Pressure Overload – Seen in patients with left to right intracardiac shunts – May passively occur in patients with left atrial hypertension and left ventricular dysfunction, mitral valve disease and hose with aortic stenosis

Pulmonary Arterial Hypertension Chest radiograph -Classic finding is enlargement of central of pulmonary arteries, attenuation of peripheral vessels and oligemic lung fields -Findings of RV and RA dilatation are possible

Pulmonary Venous Hypertension Secondary to increased resistance to pulmonary venous drainage Associated with diastolic dysfunction of the LV and valvular dysfunction Features – Capillary congestion – Focal alveolar edema – Dilatation of interstitial lymphatics

mild cardiomegaly normal pulmonary arterial markings pulmonary venous congestion fluid within the horizontal fissure prominent Kerley B lines (indicative of lymphatic engorgement) mild cardiomegaly normal pulmonary arterial markings pulmonary venous congestion fluid within the horizontal fissure prominent Kerley B lines (indicative of lymphatic engorgement) Lateral chest film show marked venous congestion with fluid visible in both the horizontal and oblique fissures

Pulmonary Arterial Congestion Pulmonary Venous Congestion “active congestion” – increased in flow of blood Passive congestion – obstructed venous outflow, swollen capillary beds Physiologic Increase blood flow into skeletal muscle (e.g. exercise) Systemic: due to RHF diminution of CO and tissue perfusion Hypoxia – decreased Hemoglobin Cyanosis Pathologic Systemic: generalized hypoxia, metabolic activity Localized acute inflammation Localized Raised LA pressure secondary to LV failure & MS Thrombotic occlusion of femoral vein