Diastolic Dysfunction (Pulmonary hypertension) Flashcards
(67 cards)
1
Q
What is pulmonary hypertension?
A
- Increased pressure in the lungs
2
Q
Which values are considered pulmonary hypertension
A
- > 30 mmHg systolic
- > 10 mmHg diastolic
- Pulmonary artery
3
Q
What affects afterload with pulmonary hypertension?
A
- Pulmonary venous/left atrial pressure
- Increase in these pressures would increase afterload, decreasing stroke volume and cardiac output
4
Q
What affects preload with pulmonary hypertension?
A
- Systemic or pulmonary venous return
- If increased, will increase preload, increase stroke volume, and increase cardiac output?
5
Q
What can increase pulmonary venous return?
A
- Any left heart disease that results in increased left atrial size will increase left atrial pressure
- Any pulmonary venous obstruction
- Loss of pulmonary vessels
- Increased right-sided cardiac output (anemia, fever, exercise; large left to right shunts)
- A mass can cause pulmonary venous obstruction too (enlarged hilar lymph nodes too)
6
Q
What is most common cause of increased pulmonary venous return?
A
- Any left sided heart disease
7
Q
What contributes to pulmonary blood pressure?
A
- Cardiac output X Pulmonary vascular resistance
- SEE TABLE AND THINK ABOUT THIS
8
Q
What large L–> R shunts can increase pulmonary venous return (AKA increased volume within the lungs)?
A
- Patent ductus arteriosus (PDA)
- Ventricular septal defect (VSD)
- Atrial septal defect
9
Q
Exercise induced pulmonary hypertension
A
- Pushing blood through the lung
10
Q
What can cause a loss of pulmonary vessels
A
- Pulmonary thromboembolism
11
Q
Again, what three things contribute to Virchow’s triad?
A
- Endothelial injury
- Blood stasis
- Hypercoagulability
12
Q
What can lead to endothelial injury leading to pulmonary hypertension?
A
- Heartworm disease***
- Vasculitis
13
Q
What can lead to hypercoagulability leading to pulmonary hypertension?
A
- Hyperadrenocorticism
- Protein-losing nephropathy
- Inflammatory disease (e.g. IMHA)
14
Q
What parts of Virchow’s triad can neoplasia impact?
A
- Any of them
15
Q
What can lead to loss of pulmonary vessels
A
- Pulmonary thromboembolism (anything impacting Virchow’s triad)
- Pulmonary vasoconstriction (hypoxemia)
16
Q
Impact of hypoxemia on pulmonary vessels?
A
- NORMALLY leads to vasodilation systemically
- In your lungs, it’s opposite
- They constrict as you don’t want to perfuse an area that’s not ventilated
17
Q
Causes of hypoxemia
A
Primary lung disease vs high altitude
18
Q
Primary lung disease that can lead to hypoxemia
A
- Chronic obstructive pulmonary disease (COPD or chronic bronchitis)
- Pulmonary fibrosis (West Highland White Terriers)
- Collapsing trachea (COMMON)
19
Q
Diagnosis pf pulmonary hypertension
A
- cardiac catheterization
- Echocardiogram
20
Q
What is the gold standard diagnosis for pulmonary hypertension?
A
- Cardiac catheterization
- Measures direct pressures in the PA, pulmonary capillaries, and pulmonary veins
21
Q
Echocardiogram for diagnosis of pulmonary hypertension
A
- Indirect measurement of pulmonary pressures
- Only definitive if tricuspid or pulmonic regurgitation is present
- Use modified Bernoulli equation to estimate pressures
- Can look for secondary signs like concentric hypertrophy too
22
Q
Treatment for pulmonary hypertension
A
- TREAT THE UNDERLYING DISEASE
- Viagra or sildenafil
23
Q
Sildenafil MOA
A
- Phosphodiesterase type V inhibitor (specific for the lung)
- Specifically vasodilates the pulmonary vasculature
24
Q
Prognosis for pulmonary hypertension
A
- Depends on underlying disease
- Usually guarded
- Most common are left heart disease, which are not curable
- Also have respiratory signs, which are not curable
25
Who gets Dirofilaria immitis?
- Canines (the favorite)
| - Felines (not as often)
26
Heartworm incidence
- Spreading
| - Definitely increasing
27
What is required for L1 to go to l3?
- 64° for 30 days
| - If it dips below 64° average, doesn't seem to support mosquito survival
28
Heartworm life cycle
- just know it
29
What stage of worm does mosquito inject into bite wound?
- L3
| - Infective 3rd stage larva
30
How long does it take to go from L3 to L4?
- 1-2 weeks in the body
31
How long to become an adult heartworm from L4?
- 2-3 months
| - Tunnels to blood vessels and molts to L5
32
How long to for patency after becoming an adult?
- 3-4 months
33
How long for patency to occur post-infection?
- 6-7 months
34
Wolbachia
- Rickettsial intracellular, gram neg bacteria
35
Wolbachia relationship to D. immitis
- Symbiotic
- Assists with D. immitis development
- Increases D. immitis fecundity
36
What stages are impacted if you kill Wolbachia?
- Fewer L3 becomes L4, and fewer of those become teenagers
| - Wolbachia help with development of life stages and facilitate more L1 larvae
37
Diagnosis of heartworm
- Heartworm testing
- Antigen testing
- ANtibody testing
- Microfilaria
38
How long after you wait before you can test for heartworm?
- 6 months post-exposure
39
What are you testing with antigen testing?
- Female reproductive tract
| - Infection
40
What does positive antigen test mean/
- Have to have an infection
41
What does antibody test positive means?
- Exposure
42
What are you looking for with Knotts test?
- Microfilaria
43
Positive predictive value and heartworm disease
- Depends on prevalence of the disease
- If you are here in Pullman, positive predictive is heartworm test is a lot lower
- Increased likelihood of false positive
- Don't test random animals for heartworm
- In Mississippi, your negative predictive value will be lower
44
What are the stages of heartworm disease?
- Asymptomatic
- Respiratory signs
- Cor Pulmonale
- Right sided CHF
- Caval syndrome
45
Respiratory signs of heartworm disease
- Cough/tachypnea with exercise
46
Cor pulmonale
- Pulmonary vascular disease --> pulmonary hypertension
47
What side heart failure happens with heartworm disease?
- Pulmonary hypertension
48
Caval syndrome
- Hepatic congestion, intravascular hemolysis with hemoglobinuria
- If pulmonary arterioles are full, they will go to the heart
- If it's even worse, they go the caudal and cranial vena cava syndrome
- These dogs are usually laterally recumbent and dying
49
Comorbidities of heartworm disease
- Antibody-antigen complex formation --> glomerular deposition --> proteinuria
- Thrombocytopenia
- Anemia
50
Concurrent diagnostics for heartworm disease
- CBC
- Chemistry
- Urinalysis
- Chest rads
- Echocardiogram
51
Why do a CBC for heartworm disease?
- Evaluate for anemia and thrombocytopenia
| - May see eosinophilia
52
Why do a chemistry for heartworm disease?
- Renal values
53
Why do a urinalysis for heartworm disease?
- Proteinuria
| - If you have protein, do a urine protein to creatinine ratio
54
Why do chest rads for heartworm disease?
- Pulmonary parenchymal and vascular changes
55
Why do echocardiogram for heartworm disease?
- Evaluate pulmonary hypertension
56
What does melarsomine kill?
- Adults
57
Preventative
Kills L1, L3, and L4
58
Slow kill method of heartworm disease
- 2+ years
- Monthly preventative dose of macrocyclic lactones
- Doxycycline PO BID for 1 month every 3 months
59
Fast kill method
- Adulticide therapy with melarsomine
- 2 dose: 1st dose and 2nd 24 hours later
- 3 dose: 1st dose, 2nd dose 1 month later, 3rd dose 24 hours after 2nd dose
- Exercise restriction the whole time
60
Which is better: slow or fast kill?
- Fast kill method
| - Especially treat ASAP if pulmonary hypertension or other co-morbidities are present
61
What is treatment of choice for caval syndrome?
- Surgical removal or worms
62
Why do surgical removal of worms?
- Reduce worm burden to minimize effects of adulticide
63
Treatment for heartworm
- SEE THE CHART IN THE NOTES
64
Feline heartworm disease characteristics
- Infection 5-20% of K9 prevalence
- Frequently amicrofilaremic
- Small worm burdens
- Clinical signs are very similar to feline asthma
65
Diagnosis of heartworm disease in cats
- Antigen: Female reproductive tract
- Antibody
- Microfilaria
- Chest rads
- Echocardiograph
- Probably will have other testing first
66
Treatment of feline heartworm disease
- Adulticide therapy not recommended
- Treat like an asthmatic cat (steroids and wait for the worms to die)
- Worm extraction?
- Doxycycline
67
What should be in place throughout all of the heartworm treatment?
- Exercise restriction!!!!
