9/23- Pulmonary Vascular Diseases Flashcards Preview

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Flashcards in 9/23- Pulmonary Vascular Diseases Deck (54)
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1

What are the systolic/diastolic/mean BP for pulmonary arteries?

Characteristics of pulmonary circulation?

Pulmonary circulation is high flow, low pressure, highly compliant system (low resistance)

- Systolic: 30 mmHg

- Diastolic: 10 mmHg

- Mean: 15 mmHg

2

What regulates vascular tone in pulmonary circulature?

Vascular endothelium

- NO (dilator)

- Endothelin (constrictor)

Autonomic nervous system

- a1 adrenergic receps (constriction)

- B2 adrenergic receps (dilation)

3

What is the mechanism of NO dilation of vasculature?

- Secreted by endothelial cells

- Activates guanylate cyclase (GC) to increase cGMP levels

- Also activates Ca dependent K channels in vascular smooth muscle

- Dilates both venous > arterial

- NO is a gas, which can be inhaled to result in primary pulmonary vasodilation

4

What are the determinants of pulmonary artery pressure?

- Blood volume

- Rate of fluid flow through system (CO, viscosity, vessel size)

- Pressure inhibiting flow across cap bed (left atrial pressure)

- PAP = CO x (PVRa + PVRcaps + PVRv)

5

What are some pulmonary vascular disorders?

- Pulmonary hypertension

- Pulmonary embolism

- Pulmonary vasculitides

- Pulmonary arteriovenous malformation

6

What is the cutoff for pulmonary HTN?

Mean PA pressure > 25 mmHg

(recall, normal is 15 mmHg)

7

How is Pulmonary HTN classified?

1. Pulmonary arterial hypertension (PAH)

- Toxin/drug use

- HIV

- Portal hypertension, liver cirrhosis

- Sickle Cell Disease

Group 1 disease have specific targeted treatments

2. Left heart disease

3. Lung diseases and/or hypoxia

- Obstructive

- Restrictive

- Chronic hypoxemia

4. Chronic thromboembolic pulmonary HTN (CTEPH)

- Persistent elevation of pulmonary P -> symptoms and heart failure

5. Unclear multifactorial mechanisms

- Sarcoidosis

8

What are the structural and functional changes in pulmonary HTN?

Increased PVR

- Sustained vasoconstriction (muscle layer hypertrophy and permeation into other layers)

- Vascular remodeling

- In-situ thrombosis

- Increased arterial wall stiffness

9

What is idiopathic Pulmonary Arterial HTN?

- Epidemiology

- Pathology

Epidemiology

- Uncommon

- More in women

- Mean age = 50 yo

Pathology

- Hypertrophy/fibrosis vascular bed

- In situ thrombosis 

10

What is the prognosis for idiopathic Pulmonary Arterial HTN?

- Variable

- Mean survival 2-3 yrs from time of diagnosis

- Depends on severity, cardiac function, exercise tolerance, response to vasodilators

  • Non-responders: 9-18 months
  • Responders w/ preserved function:- >50% for 5 yrs

11

What are the clinical features of PAH?

- Shortness of breath

- Atypical chest pain

- Palpitations

- Cough

- Syncope (if advanced; developing RHF)

- Hemoptysis

- Hypotension

- Tachycardia

- Atrial arrhythmias

- Loud P2

- Tricuspid regurgitation murmur

- JVD

- Signs and symptoms of cor pulmonale (RHF)

12

Case)

- 45 yo female with worsening SOB

- Chest pain, orthopnea, PND What is seen on her CXR? 

- Don't see infiltrate, pneumonia, fibrosis

- Preserved lung structure/anatomy

Heart seems somewhat abnormal:

- Large pulmonary artery indicative of pulmonary HTN 

13

What is seen of echocardiogram of pulmonary HTN?

- Small LV cavity; normal LV ejection fraction

- Severe RV dilatation, severely reduced RV global systolic function

- PA systolic pressure estimate 105-110 mmHg

- No interatrial septal defect

14

What does the evaluation of suspected pulmonary HTN look like?

- ECHO to screen for PH and r/o primary cardiac disease

- PFT to r/o primary lung disease (esp. COPD) and restrictive lung disease

- Spiral CT (possible angiogram) to r/o pulmonary vascular disease (thromboembolic disease, vasculitis)

- Right heart cath: Pulmonary artery pressure, PCWP, hemodynamics

15

What is the treatment for PAH (pulmonary HTN in general?) ?

- Optimize therapy for related diseases

- Supportive (O2, anticoagulation, diuretics, digoxin)

- Targeted therapy - Surgical

16

What are targeted therapies for PAH?

- Prostacyclins

- Endothelin receptor antagonist

- NO pathway drugs

- Soluble guanylate cyclase stimulators

17

What are characteristics of prostacyclins for PAH treatment?

Examples (probably don't need to name)?

Vasodilatory, antiplatelet, antiproliferative

- Berapost (PO)

- Epoprostenol (IV)

- Iloprost (inhaled)

- Treprostinil (SQ, IV, inhaled, PO)

18

What are characteristics of endothelin receptor antagonists for PAH treatment?

Examples (probably don't need to name)?

Blocks receptor for ET-1, a potent vasoconstrictor and mitogen

- Bosentan (PO)

- Ambrisentan (PO)

- Sitaxsentan

19

What are examples of NOs for PAH treatment (probably don't need to name)?

- Phosphodiesterase inhibitors: Sildenafil/Tadalafil

- Inhaled NO

- Dipyridamole

20

Name soluble guanylate cyclase stimulators (probably don't need to name)?

Riociguat

21

What are surgical therapies for PAH?

Lung transplantation

- Double lung transplantation typically

- Heart-lung if PAH secondary to congenital heart disorders

Atrial septostomy

- Reduces RVEDP, improves cardiac index at expense of decreased PaO2

- Bridge to transplantation

Pulmonary endarterectomy for CTEPH

22

What is cor pulmonale?

- Cause

- Signs

- RV hypertrophy (and ultimately resulting in right heart failure) 2ndary to increased PVR

- Most commonly results from chronic pulmonary diseases (esp. COPD) that affect pulmonary vasculature.

- Signs:

  • Hepatojugular reflux
  • Lower extremity edema
  • Pulsatile liver
  • Tricuspid regurgitation
  • Ascites

23

What is the treatment for cor pulmonale?

- Treat underlying cause(COPD, etc.)

- Minimize vasoconstriction, vasodilate (O2),

- Improve cardiac output w/rhythm control and contraction

24

Epidemiology of PE/DVT?

- Venous thromboembolism is a major medical problem

- > 5 million DVT cases annually

- Of these, 650,000 develop pulmonary embolism (PE)

- Of pts with PE, 100,000 die annually

- Not uncommon cause of death in acute care hospital setting

- > 70% of pts that die of PE are not suspected before death; maintain a high index of suspicion and pursue the diagnosis when warranted

25

What are causes of pulmonary embolism?

- Thrombus

- Fat (occurs in long bone fractures)

- Tumors

- Trophoblast

- Air (catheter placement, scuba diving)

- Amniotic fluid

26

What is VIrchow's triad?

1. Venous stasis

2. Intimal injury

3. Altered coagulation

27

What are the risk factors for thrombosis?

- Age > 70 yo

- Obesity

- Sedentary/Bed rest

- Trauma

- Chronically ill

- Pelvic surgery/trauma

- Prolonged anesthesia (>1 hour)

- Surgery of lower extremities

- Hip fracture/replacement

- Pregnancy/postpartum

- Right ventricular failure

- Oral contraceptives (5-10 fold increase)

- Underlying malignancy (Trousseau’s syndrome)

- Inherited/acquired deficiency of naturally

  • occurring anticoagulants:resistance to activated protein C (Factor V Leiden)
  • Prothrombin gene mutation
  • protein C deficiency
  • protein S deficiency
  • Antiphospholipid antibody syndrome
  • Anti-thrombin III deficiency
  • Hyperhomocysteinemia

28

What are symptoms of DVT?

- Pain

- Tenderness

- Swelling

- (+) Homan's sign: dorsiflexion of foot/ankle -> pain

29

What are the symptoms and findings of pulmonary embolism?

Symptoms

- Dyspnea

- Impending doom

- Palpitations (tachycardia)

- Hemoptysis and pleuritic chest pain are signs of infarction (uncommon, 20% of patients with significant cardiopulmonary disease)

Findings

- Tachypnea

- Tachycardia

- Low grade fever

- With massive embolism

- fixed split of S2, and S3 or S4, dilated neck veins, and cyanosis, hypotension

30

What is the diagnostic process of DVT?

- Contrast venography: Gold standard, only accurate method in asymptomatic individuals.

- IPG: Serial negative IPG or US is comparable in accuracy to negative venography in patients with suspected DVT

- Compression ultrasonagraphy*: Often the diagnostic modality of choice. The sensitivity and specificity approach 97%-98% for symptomatic patients.

- MRI: High sensitivity and specificity, expensive

- D-dimer: Low levels of plasma D-dimer (under 500 ng/mL) by ELISA technique may have a high negative predictive value