Pulmonary Vascular Disease Flashcards
Pulmonary Arteriovenous Malformations (PAVM): definition
- abnormal communication between artery and vein
Why do patients get hypoxemic with an AVM
Shunt: no O2 exchange
Mechanisms of injury to pulmonary vasculature
- pulmonary embolus
- pulmonary arteriovenous malformation
- inflammation of vessels
- scarring of vessels
- pulmonary edema
Types of pulmonary embolisms
- thrombus
- tumor
- fat
- air
What is a saddle PE
lodges in bifurcation of the pulmonary artery
Method of increased mortality of PE
- unstable: hypotesion (SBP15 min
- much higher mortality up to 72 hrs
Individuals at risk for PE
- Women have increased risk
- obesity, smoking, hypertension, prolonged travel, immobilization, oral contraceptives
Populations at risk for PE
- malignancy, pregnancy, stroke, hospitalized patients, nephrotic syndrome, acute spinal cord injury, joint replacements, inherited disorders
Prediction model of PE & probability
- Wells Score
- probability: high>6, moderate: 2-6, low
Diagnosis: labs & imaging
- labs: D-dimer (fibrin degradation product indicating recent coagulation) **do this first, then proceed if positive
- imaging: CT angiogram (gold standard), VQ scan
Why do PEs occur
- Virchow’s Triad: venous stasis, endothelial injury, hypercoagulable state
- arise from lower extremity proximal veins usually
What happens when you get PE
- lung infarction
- low oxygen
- impairs CO
- V/Q mismatch
Why do you get impaired CO w/ PE
- increased PVR leads to RV dilation, flattening IV septum, compressing LV space, which ultimately leads to decreased CO
Treatment of PE
- supportive care: oxygen, vasopressors, ventilator
- thrombolytics
- anticoagulation (minimum of 3 months): heparin or fondaparinux then go home with oral coumadin, factor Xa inhibitors, or direct thrombin inhibitors
- IVC filter (rarely used): net that catches things in IVC
What does presentation with cyanosis tell you?
- CHRONIC hypoxia
Pulmonary AVM: how are they grouped
- defined by size and how many feeding/draining vessels
Pulmonary AVM: location
- usually lower lobe (70%)
Pulmonary AVM associated with
- HHT (30%)
- trauma
- hepatopulmonary syndrome
Causes of mortality with pulmonary AVM
- stroke
- cerebral abscess
- hemoptysis
- hemothorax
Treatment of pulmonary AVM
- embolization: clot off vessels
- surgery
Differential Dx of cavitating lung nodules
- infection: septic emboli, fungal infection
- malignancy
- vasculitis
- primary rheumatologic disease
Lab presentation of ANCA vasculitis (granulomatous with polyangitis)
- elevated creatinine w/ sediment in urine
- C-ANCA elevated along w/ anti-PR3
Vasculitis most common location
- small vessels of the lung
Vasculitis types that present w/ kidney disease
- granulomatosis w/ polyangitis (Wengener’s/C-ANCA vasculitis)
- goodpasture’s disease (antibodies to collagen in basement membrane-autoimmune disease)
- lupus
Classification of vasculitis & those occurring lungs
- classified by size of vessels effected
- occurring in lungs: microscopic polyangitis, granulomatosis w/ polyangitis
Suggestive features of vasculitis
- mononeuritis multiplex (asymmetric polyneuropathy)
- palpable purpura
- pulmonary-renal
- fevers, myalgias, athralgias
Diagnosis of ANCA vasculitis
- clinical picture
- radiographs
- histology (BIOPSY)
- lab - ANCA
What is essential to diagnosis of vasculitis
- Tissue Biopsy
Features seen on biopsy w/ vasculitis
- granulomas
- inflammatory cells around vessels
Epidemiology of ANCA vasculitis: incidence & prevalence
- incidence: 15-20 per million/year
- prevalence: 90-300/million
Survival with ANCA vasculitis
1 year: 88%
3 year: 85%
5 year: 78%
Clinical features of granulomatosis with polyangitis
- airway: nose involvement, otitis, sinusitis (85%)
- lung parenchyma: focal consolidation/infiltrates/nodules (80%)
- alveolar hemorrhage: 5-10%
- extrapulmonary: glomerulonephritis, skin
ANCA lab testing
c-ANCA: cytoplasmic, proteinase-3 (PR3) antigen
p-ANCA: perinuclear, myeloperoxidase (MPO) antigen
ANCA associated vasculitis (AAV) treatment
- RITUXIMAB, corticosteroids, cyclophosphamide (immunosuppression)
- rarely plasma exchange
AAV remission and relapse
- remission rate: 90-94%
- time to remission
AAV survival
- 5 months if untreated GPA
- 21.7 years in treated GPA
Pulmonary hypertension: definition
- pathophysiological & hemodynamic condition
- increase in resting MAP > 25 mmHg by right heart catheterization
Right heart failure w/ PH
- used to low pressure system of right side
- less reserve than left ventricle
- right coronary blood flow occurs ONLY in diastole in PH (normally throughout entire cycle)
- RV ischemia in the setting of increased RV metabolic demand
Essential to diagnosis of PH
- right heart catheterization
Right heart catheterization: where is the problem
- pre capillary: low wedge
- post capillary: high wedge
Groups of pulmonary hypertension
- pulmonary arterial hypertension (PAH)
- left heart disease
- chronic lung disease
- chronic thromboembolic PH
- unclear mechanisms
Cause of PAH
- idiopathic
- hereditary: BMPR2 mutation (70%)
- connective tissue disease: scleroderma
- drugs: appetite suppressants, meth, cocaine, st. johns wart
- HIV (1/200 patients)
Definition of PAH
- right heart cath
- resting mean PAP > 25mmHg
- exercise mean PAP > 30mmHg
- wedge
Left heart disease PH
- most COMMON cause (65%)
- systolic or diastolic dysfunction
- valvular disease, cardiomyopathy, pericardial disease
Lung disease PH (group 3)
- COPD, ILD, CPFE, sleep disorder, alveolar hypoventilation, chronic exposure to high altitude
- obliteration of vascular bed
- hypoxic vasoconstriction
Chronic thromboembolic disease PH
- persistent pulmonary hypertension 6 months after PE
- 2-4% of patients after PE
- small vessel arteriopathy distal to thrombosis
- SURGICAL treatment w/ cure
- *only type of PH you can surgically treat**
Idiopathic PH survival
- median survival 2.8 years by early NIH registry
- has now improved drastically
Why does PH occur
- genetic predisposition, then some sort of injury (hypoxia, meth) leading to inflammation and scarring
PAH histologic features
- intimal and medial thickening
- intimal fibrosis and in situ thrombosis (complex plexiform lesions)
How to treat PH in groups 2-4
- FIND and treat underlying disease
How to treat idiopathic PAH
- therapies that relax pulmonary arteries
- if accompanied by HF then treat that as well
Treatment pathways of PAH
- endothelial: endothelin receptor antagonists
- nitric oxide: phosphodiesterase 5 inhibitor (prevent breakdown), exogenous nitric oxide (riociguat)
- prostacyclin pathway: prostacyclin derivatives (systemic vasodilation)
Diseases of pulmonary vasculature
- obstruct: PE
- malform/connect: AVM
- inflame: vasculitis
- scar: pulmonary arterial hypertension
- leak: ARDS, CHF
Why do people get low oxygen in PE
V/Q mismatch: bases of lungs better V/Q matching and if they get blocked off the upper lobes are only place for O2 exchange and they don’t have as good V/Q matching
