Pulmonary Hypertension Flashcards
define pulmonary hypertension
- abnormally increased pressure within the pulmonary vasculature
- mean pulmonary aterial pressure (PAP) > 25 mmHg
how is pulmonary arterial pressure measured?
echocardiogram allows us to eval heart best!
during pulmonary hypertension, blood regurgitates from the right ventricle through the tricuspid valve into the right atria instead of out through the pulmonary artery
we measure the peak tricuspid regurgitation velocity to give an idea of how severe the PH might be
-measured by doppler echo to estimate the systolic pulmonary artery pressure
-use simplified Bernoulli equation to get tricuspid regurg pressure gradient
describe clinical presentation of pulmonary hypertension
age:
-very young = think shunts (PDA)
old: think pulmonary fibrosis, hypercoagulable disease
breed:
-small breed: MMVD, tracheal collapse
-brachycephalic: BOAS, heart base masses
-westies: predisposed to pulmonary fibrosis
location:
-if living in the south, think parasites!
describe the 3 groups of diseases that can cause pulmonary hypertension
- increased pulmonary blood flow
-ex. left to right shunts (PDA) - increased pulmonary vascular resistance
-something causing vasoconstriction or obstructing blood flow in capillaries - increased pulmonary venous pressure
-ex. left heart disease
relate the tricuspid regurg pressure grafdient to the severity of PH
> 30mmHg = mild
> 50 = moderate
> 70 = severe
describe clinical symptoms suggestive of PH
possibly suggestive:
1. tachypnea at rest
2. increased respiratory effort at rest
3. prolonged post-activity tachypnea
4. cyanotic or pale MM
strongly suggestive:
1. syncope
2. respiratory distress at rest
3. activity ending in resp distress
4. right sided CHF
describe physical exam of pulmonary hypertension
- respiratory:
-cyanosis and coughing secondary to airway or lung disease
-respiratory pattern can help ID which part of resp system affected - cardiovascular:
-left apical murmur: MMVD
-right basilar murmur: tricsupid valve regurgitation - auscultation:
-may have crackles, wheezes, or increased lung sounds if underlying lung disease - other:
-jugular vein distension
-ascites
-pleural effusion
-all indicate right sided heart failure
what is commonly seen on thoracic radiographs of PH
right sided cardiomegaly is classically seen first
describe treatment goals of ALL types of PH
- decrease risk of progression:
-exercise restriction
-prevent resp infections and parasites (vx and preventatives)
-avoid pregnancy and obesity
-avoid high altitudes and air travel
-avoid nonessential procedures and elective surgeries requiring anesthesia! - treat underlying disease
-different for each group, more to come - reduce pulmonary arterial pressure:
-sildenafil/viagra!
-MOA: phosphodiesterase, an enzyme produced in the lungs breaks down cGMP into inactive GMP, decreasing the enzyme’s activity so more cGMP is available to relax the arteries
what causes pulmonary hypertension? (6)
- pulmonary arterial hypertension
- left heart disease
3.
describe how pulmonary arterial hypertension causes PH
- causes increased pulmonary bloodflow
-due to: congenital left to right shunts (PDA, ventricular or atrial septal defect), or idiopathic
diagnosis:
-usually very loud murmurs (washing machine)
-thoracic rads (ductus bump), echocardiogram (to ID shunt)
treatment:
-close shunt if possible
-can consider sildenafil
-may need lifelong management
describe PH due to left heart disease
causes:
1. left ventricular dysfunction: dilated cardiomyopathy
2. valvular disease: MMVD
3. aortic stenosis
diagnosis:
-thoracic rads:
–left atrial enlargement
–right sided enlargement
– +/- pulmonary edema
-echocardiogram: help specify cause of left sided disease
treatment:
-pimobendan
-ACE inhibitors
- +/- furosemide
-do NOT recommend sildenafil: will increase preload to left heart and can worsen failure!
describe PH due to respiratory disease/hypoxia
hypoxic pulmonary vasoconstriction: intrapulmonary arteries constrict in response to alveolar hypoxia, diverting blood to better-oxygenated segments
causes:
1. chronic obstructive airway diseases: tracheal or bronchial collapse, BOAS
- pulmonary parenchyma disease: pulmonary fibrosis, infectious pneumonia, feline asthma
- chronic high altitude exposure
- emphysema
diagnosis:
-upper airway disease? (BOAS, tracheal collapse, laryngeal paralysis)
–yes: confirm with upper airway exam and treat accordingly
–no: obtain thoracic rads; often give you an idea of disease process
-if disease not clear: perform airway wash, culture, and/or biopsies
treatment:
1. treat underlying disease:
-BOAS: surgery
-pneumonia: abx
-feline asthma: bronchodilator and steroids
-the rest? probs steroids
- DO recommend sildenafil for these patients!
describe PH due to thromboembolic disease
causes:
1. acute or chronic pulmonary thromboembolism:
-blood clot breaks off and travels to another part of the body
-lodges in main pulmonary artery = usually die acutely
-lodges in smaller vessels = can survive
- usually secondary to hypercoagulable states: Cushing’s, protein losing disease, neoplasia, infections
diagnosis:
1. thoracic rads:
-if signs of PE/PT/PTE, move to chest CT (lol) and look for clot to definitively diagnose
treatment:
1. treat underlying disease
2. anticoagulation: clopidogrel (anti-platelet)
3. sildenafil recommended
describe PH due to parasitic disease
causes:
1. heartworm: dirofilaria immitis
2. lungworm: angiostrongylus vasorum
diagnosis:
-HW: thoracic rads, microfilaria ID, snap 4Dx test
-lungworm: endotracheal wash analysis, feces analysis and ID
treatment:
-HW: HWS guidelines, consider sildenafil if PH symptoms severe
-lungworm: moxidectin or fenbendazole +/- steroids, can consider sildenfail if PH symptoms severe
