Pulmonary circulation II

Question 1

5. Define pulmonary hypertension and its causes

Answer 1

Mean Pulmonary Artery Pressure > 25 mmHg. Normal is 15-18mmHg. Causes include increased pulmonary vascular resistance and increased left atrial pressure (and increased CO if it is severe enough)

Question 2

Two types of pulmonary hypertension

Answer 2

pre capillary: Pulmonary arterial hypertension, post capillary wedge pressure is 15mmHg

Question 3

Classifications of pulmonary hypertension (Dana point)

Answer 3

1. Pulmonary Arterial Hypertension 2. PH Due to Left Heart Disease 3. PH Due to Lung Diseases and/or Hypoxia 4. Chronic Thromboembolic Pulmonary Hypertension 5. PH With Unclear/Multifactorial Mechanisms

Question 4

Sub categories of group 1 pulmonary arterial hypertension

Answer 4

idiopathic, heritable, drugs/toxins, connective tissue disease, HIV, portal hypertension, congenital heart disease, schistosomiasis

Question 5

Causes of acute pulmonary hypertension

Answer 5

Pneumonia, thromboembolic disease and hypoxia (high altitude)

Question 6

Diagnostic evaluation of acute pulmonary embolism

Answer 6

History and physical (wells score), D- dimer (breakdown products of thrombin), ECG, CXR, VQ scan, CT angiogram, angiogram, echocardiography

Question 7

ECG findings in acute PE. CXR findings in PE

Answer 7

sinus tachycardia on ECG. CXR is usually normal (used to exclude other processes), but may see Hampton’s hump (infarcted lung) or Westermarks sign (hypoperfusion)

Question 8

VQ scan findings in acute PE

Answer 8

2 large mismatched defects indicates high probability of PE, 1 moderate mismatched defect indicates intermediate probability. Matched defects only indicate low probability of PE

Question 9

Treatment of acute PE

Answer 9

If stable: Parenteral Anticoagulation -Heparin: Unfractionated or low molecular weight, Oral Anticoagulation - warfarin. If unstable (hypotensive, RV failure): Heparin, Consider thrombolysis (tPA), Consider IVC Filter, Consider surgical thrombectomy

Question 10

Idiopathic pulmonary arterial hypertension - population affected, outcome

Answer 10

Affects young women (30s-40s). Life expectancy is only 2.8 yrs if not treated. Patients usually die from ventricular arrythmias (the RV becomes dilated then hypertrophies) or drop in CO with RV failure.

Question 11

idiopathc pulmonary hypertension description

Answer 11

Targets pulmonary vasculature while sparing the lung parenchyma (pre capillary pulm HTN)

Question 12

Idiopathic pulmonary hypertension CXR

Answer 12

over time, congestion in lungs gets worse

Question 13

Pulmonary arterial hypertension histopathology

Answer 13

Can have eccentric intimal thickening, concentric intimal thickening, plexiform lesion, dilated/angiomatoid lesions. Precapillary vessel muscularization, medial hyperplasia with intimal thickening, adeventitial thickening

Question 14

Pulmonary arterial hypertension hemodynamic changes

Answer 14

Early stage: pulmonary vascular resistance and pulmonary arterial pressure rise, but cardiac output is stable. Middle stage: PVR and PAP continue to rise, CO starts to decline. Late stage: CO decreases, PVR continues to increase, mean pulmonary arterial pressure may decrease due to CO decreases.

Question 15

Vasculature changes over time in pulmonary arterial hypertension

Answer 15

Early stage: minimal changes. Middle stage: pulmonary vasculature shows intimal proliferation and smooth muscle hypertrophy. Late stage: smooth muscle hypertrophy, intimal hyperplasia, thrombosis, plexiform lesions

Question 16

pulmonary arterial hypertension symptoms

Answer 16

chest pains, palpitations, orthopnea, exercise tolerance, lower extremity edema, pre syncope.

Question 17

Medical history and medications associated with PAH

Answer 17

medical history: heart disease, collagen vascular disease, previous pulm embolism, liver disease. Drugs: fenfluramine, anorexic drugs, methamphetamine

Question 18

Pulmonary arterial hypertension physical exam

Answer 18

distended neck veins, normal lung ascultation (no rales), loud S2 and murmur of tricuspid valve, edema in extremities

Question 19

Causes of pulmonary hypertension due to lung disease/ hypoxia

Answer 19

COPD, ILD, Other pulmonary diseases with mixed restrictive and obstructive pattern, Sleep-disordered breathing, Alveolar hypoventilation disorders, Chronic exposure to high altitude, Developmental abnormalities

Question 20

Pathophys of PH due to lung disease and expected PFTs

Answer 20

PH results from impaired ventilation (and resultant hypoxemia causing chronic hypoxic vasoconstriction and remodeling) and/or destruction of the lung (i.e. emphysema, fibrosis). In these cases DLCO will be decreased proportionally with FEV1 and FVC.

Question 21

Causes of chronic hypoxia

Answer 21

chronic high altitude, obstructive lung disease, interstitial lung disease, chest wall defects, alveolar hypoventilation, pleural disease/fibrosis, sleep apnea

Question 22

Treatment of chronic thromboembolic pulmonary hypertension

Answer 22

pulmonary endarterectomy + anticoagulation

Question 23

Treatment of non speciic pulmonary arterial hypertension

Answer 23

Treat underlying cause, Correct hypoxia, Control intravascular volume status (Limit fluid intake, Limit sodium intake, Diuresis), Anticoagulation(?), Pulmonary vasodilators

Question 24

Key Pathways Implicated in PAH Pathogenesis

Answer 24

Increased endothelin, decreased NO and/or decreased prostacyclin all lead to vasoconstriction and proliferation of smooth muscle cells.

Question 25

Vasodilators used in treatment of PAH

Answer 25

Endothelin Receptor Antagonists (Oral- bosentan, ambrisentan, macitentan), Phosphodiesterase inhibitors (Oral- Sildenafil, tadalafil, Riociguat (soluble guanalyl cyclase stimulator)), Prostacyclins (IV, Sub-Q, Inhaled, and Oral- Epoprostenol, iloprost, trepostinil), Calcium channel blockers (for patients that respond to inhaled NO- Diltiazem, nifedipine, amlodipine)

Question 26

Definition of vasodilator response

Answer 26

Fall in mPAP ≥10 mm Hg + PAPm (absolute) <40 mm Hg + Normal CO

Question 27

Calcium channel blockers and PAH

Answer 27

Only acute vasodilator responders should be tried on CCB therapy to treat PAH

Question 28

Treatment of pulmonary venous hypertension

Answer 28

Decrease intravascular filling (Limit fluid intake, Limit sodium intake, Diuresis), Improve LV contractility (decrease LV afterload by controlling systemic hypertension), Correct causes of LV failure (Ischemia , Valvular disease)

Question 29

Pulmonary function tests in pulmonary hypertension from primary vascular disorders

Answer 29

PAH, embolic disease and chronic low O2 exposure affect the pulmonary vessels only. DLCO will be low with normal lung function on PFTs. DLCO is decreased due to poor perfusion through blood vessels or absence of effective blood vessels for gas exchange which decreaases blood flowing past alveoli.

Question 30

What diagnostic test can be used to classify pulmonary hypertension as pre vs post capillary

Answer 30

history/PE, CXR, ABG, PFTs, cardiac echo, VQ, CTA