Pulmonary Arterial Hypertension www medslides com 598 Med

Pulmonary (Arterial) Hypertension www. medslides. com 5/98 Med. Slides. com 1

Definitions • Pulmonary arterial hypertension – acute (pulmonary embolism, ARDS) – chronic (clinically more common) • Pulmonary venous hypertension – pulmonary venous (LA pressure) > 12 mm. Hg – Hallmarks: pulmonary congestion and edema – Invariably, PVH elicits PAH • Cor Pulmonale – pulm HTN with RV hypertrophy and dilatation 5/98 Med. Slides. com 2

Survival as a Function of Mean Pulmonary Arterial Pressure Mean PA Pressure mm Hg 5/98 Prog Resp Res 1975, 9: 10 Med. Slides. com 3

Pulmonary Circulation • Before birth – pulmonary and systemic pressure are equal in the order of 70/40 (mean 50) • After birth – ductus arteriousus closes, lung expands, PA pressure falls to 1/2 of systemic level – PA pressure gradually decrease over weeks to reach adult level 5/98 Med. Slides. com 4

Pulmonary Circulation • Pulmonary circulation is “protected” from being hypertensive – large capacity – great distensibility – low resistance – modest amounts of smooth muscle in the small arteries and arterioles 5/98 Med. Slides. com 5

Pulmonary Hemodynamics PA pressure (mm. Hg) LA pressure (mm. Hg) Cardiac Output PVR (R Unit) Sea Level Altitude 15, 000 ft 20/12, 15 5. 0 6 L/min 1. 7 38/14, 25 5. 0 6 L/min 3. 3 PA - LA PVR = ---------- ; CGS units = R units x 80 Cardiac Output 5/98 Med. Slides. com 6

Pulmonary Arterial Hypertension pathophysiology • Decrease in total cross-sectional area – lung resection • Narrowing of the lumen of the small muscular arteries and arterioles resistance vessels ( P = Q x R) – chronic hypoxia with vasoconstriction 5/98 Med. Slides. com 7

Primary or Idiopathic Pulmonary Hypertension • • 5/98 Plexogenic Thromboembolic (small emboli) Veno-occlusive disease Pulmonary capillary hemangiomatosis Med. Slides. com 8

Secondary Pulmonary Hypertension • Hypoxic – chronic lung disease, sleep apnea • Pulmonary Venous Hypertension – mitral stenosis, left ventricular failure • Congenital Heart Disease – Eisenmanger’s, PDA, ASD, VSD • Vascular Obstruction – thromboembolism, systemic vasculitis 5/98 Med. Slides. com 9

Evaluation • Right heart catheterization – “gold standard” for the diagnosis of PH • Chest Radiography – findings depends on the duration and etiology – enlargement of the pulmonary trunk and hilar vessels, pruning of the peripheral tree, RV – hyperinflation, flattening of the diaphragm • Electrocardiogram – RV enlargement 5/98 Med. Slides. com 10

Evaluation • Ultrasound – assess RV wall thickness and function – estimate pulmonary pressure from TR jet • Lung Scan – rule out pulmonary thromboembolic disease • Radionuclide Studies – evaluate RV function • Lung Biopsy – identify interstial or collagen vascular disease 5/98 Med. Slides. com 11

Evaluation • • Arterial blood gas Pulmonary function test Collagen vascular serology Lower extremity venogram or compressive ultrasonography • CBC and peripheral blood smear • Stool and urine for parasites • Polysomnogram 5/98 Med. Slides. com 12

Left-heart failure Congenital heart disease Passive Pulm HTN Increased blood flow Abnormal vasoconstrictive response Reversed shunt Hypoxemia Pulmonary Hypertension RVH / Cor Pulmonale RV Failure 5/98 Erythrocytosis Med. Slides. com 13

Pulmonary Venous Hypertension • Elevated LV diastolic pressure – LV systolic or diastolic failure – constrictive pericarditis • Left atrial hypertension – mitral valve disease – Cor triatum – left atrial myxoma or thrombus 5/98 Med. Slides. com 14

Left ventricular failure • LV failure is the most common cause of pulmonary hypertension • LV failure is the most common cause of right ventricular failure - attributable to failure of the muscle in the shared ventricular septum 5/98 Med. Slides. com 15

Congenital Heart Disease • Pulmonary hypertension is associated with many types of CHD, and often a major determinant of it’s clinical course • Large left-to-right shunt ( blood flow) – atrial septal defect, ventricular septal defect, patent ductus arteriosus • Right-to-left shunt ( vasomotor tone) – hypoxia with in red cell mass 5/98 Med. Slides. com 16

LV-RV Inter-dependance Normal Heart ED Pressure RV LV 5/98 LV RV ED Volume Med. Slides. com 17

Dilated RV Compressed “D” shaped LV 5/98 LVED Pressure LV-RV Inter-dependance Acute RV Distention Distended RV Normal RV LVED Volume Med. Slides. com 18

Thromboembolic Disease • A form of occlusive pulm vascular disease – thromboembolic (U. S. and Europe) – schistosomiasis (Egypt) – filariasis (Asia) • Categorization by arterial segment occlusion – small (attributable to organized thrombi) – intermediate (clots from upper legs and thighs) – large (chronic proximal thromboembolism) 5/98 Med. Slides. com 19

Respiratory Disease and Disorder Chronic Lung Disease Hypoxia Polycythemia Hypercapnia Acidosis Pulmonary Hypertension Restricted Pulmonary Vascular Bed RV Dilatation and Hypertrophy RV Failure 5/98 Med. Slides. com 20

Respiratory Disease and Disorder • • Intrinsic disease of lung and/or airways Interstitial fibrosis Chronic obstructive lung disease Conglomerate fibrosis, emphysema, and chronic bronchitis • Collagen vascular disease • Alveolar hypoventilation (sleep apnea, abnormal respiratory control, chest bellows) 5/98 Med. Slides. com 21

Miscellaneous Causes • • • 5/98 residence at high altitude hemoglobinopathies intravenous drug abuse alveolar proteinosis Takayasu’s disease Med. Slides. com 22

References • • 5/98 Hurst’s The Heart, 8 th Edition, 1994 Schlant RC, Alexander RW, O’Rourke RA, Roberts R, Sonnenblick EH Hypoxia and pulmonary hypertension in chronic bronchitis. Bishop JM. Prog Resp Res 1975, 9: 10 Med. Slides. com 23