1. Differentiate Pulmonary arterial hypertension from pulmonary venous congestion

2. 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

3. 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

4. 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

5. 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

7. 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

8. 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

9. 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