Systemic and Pulmonary Hypertension Flashcards by Corinne Perra

T/F: systemic hypertension usually occurs secondary to another condition in cats and dogs

True

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What is the basic pathophysiology causing systemic hypertension?

Arterial/arteriolar walls are disease and vessel lumen is narrowed - > reduced blood flow to tissues and/or hemorrhage due to vessel/capillary fragility

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Who should we test for systemic hypertension?

Patients with ..
-target organ damage (eyes, kidney, CNS, or CVS)

-associated conditons

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Renal damage can be associated with systemic hypertension. What are the potential clinical signs?

Isosthenuria
Azotemia
Proteinuria
Structural abnormalities (eg atrophy)

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What type of renal damage can systemic hypertension cause?

Glomerular and/or tubulointersitial

Ischemia, necrosis, and atrophy

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What are potential clinical signs associated with ophthalmic damage due to systemic hypertension?

Vision loss
Retinal hemorrhage/edema
Retinal detachment
Intraocular hemorrhage (hyphema)

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What are potential clinical signs associated with neurological damage due to systemic hypertension?

Seizure 
Vestibular signs 
Disorientation 
Mentation or behavior change 
Signs may be transient or persistent

-“hypertensive encephalopathy” good prognosis with normalization of BP

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What cardiovascular changes can you see due to systemic hypertension?

LV concentric hypertrophy
—> pressure

Diastolic dysfunction
Mitral regurgitation

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What are potential clinical findings associated with CV damage due to systemic hypertension?

L sided CHF signs
Epistaxis 
Mitral murmur 
Cardiac gallop 
Arrhythmia 
L- Sided cardiomegaly and proximal aortic dilation

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What is a common condition in cats and dogs causing systemic hypertenion?

Renal disease

Diabetes mellitus
Obesity
Hyperaldosteronism
Pheochromocytoma

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What medication do dogs often receive for urinary problems that may make them hypertensive ?

Phenylpropanolamine (A agonist) —> tighten urethral sphincter

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What are the differentials for systemic hypertension?

True/pathologic hypertenion

secondary (most common)
idiopathic/primary

Stress-induced hypertenion (“white coat”)

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How can you avoid stress-induced hypertension?

Ensure good technique
Rule out/treat co-morbidities that could cause high BP

Measure BP with owner present
Change room/personnel
Verify abnormal readings at other sites

Proper equipment
Verify correct cuff size

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What are the steps in making a diagnosis of systemic hypertension ?

PE to evaluate for TOD
Obtain multiple reliable BP readings
Testing for associated conditions (eg renal disease)

If TOD is present or if BP >180 —> treat for hypertension
If not —> reassess in a week

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What do you do to investigate an underlying cause of systemic hypertension?

Minimum database: CBC, Biochem, UA

Additional diagnostics in select patients: endocrine testing, UPC, urogenital ultrasound, thoracic radiographs, echo, Catecholamines levels

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What patients with systemic hypertension are usually admitted as inpatients? What are the usual drugs used?

Those with ocular and/or neuro signs

Nitroprusside CRI
Hydralazine
Acepromazine

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What is the first choice treatment for systemic hypertension in doggos?

Angiotensin-converting enzyme inhibitor (ACEi)

—> indirect vasodilator blocking angiotensin II

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When are ACE inhibitors contraindicated ?

Dehydrated and hypovolemic patients

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What is the MOA of amlodipine ?

Dihydropyridine-type Ca channel blocker

—> inhibit Ca influx across vascular smooth muscle cells

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What is the first choice treatment for systemic hypertension in cats?

Amlodipine

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What combo of drugs do you use in cats with systemic hypertension that do not respond to a single drug?

Amlodipine and ACEi

What technique can be used to reduce stress-induced hypertension?

Environment

quiet and comfortable
with our without owners
5-10mins to acclimate
minimal distractions
minimal restraint
co-morbidities?

Personnel

skilled
informed
gentle

Equipment (calibrate)

Doppler vs oscillometric
several cuff sizes
ultrasound gel- Doppler
alcohol

Lateral or sternal recumbency (artery at level of the heart)

What is the normal systolic pulmonary arterial pressure?

30mmHg

What is the calculation for pulmonary arterial pressure?

PAP = (cardiac output x pulmonary vascular resistance) + pulmonary venous pressure

What are the mechanisms of pulmonary hypertension?

Increased cardiac output Increased pulmonary vascular resistance/radius -increased vasoconstriction or decreased vasodilation Increased pulmonary venous pressure

pulmonary hypertension is classified based on underlying disease processes. What are these classifications?

1. due to pulmonary vascular disease 2. Due to left-sided heart disease 3. Due to chronic pulmonary disease /hypoxia 4. Due to thrombotic/embolic disease 5. Misc (compression of vessels -neoplasia or granuloma)

What are causes of pulmonary vascular disease leading to pulmonary hypertension ?

Parasitic -eg heartworm Congenital systemic-to-pulmonary shunt (PDA or VSD) Idiopathic

What are causes of left-sided heart failure leading to pulmonary hypertension?

Degenerative mitral valve disease Dilated cardiomyopathy —> increased pulmonary venous pressure

What are causes of chronic pulmonary disease leading to pulmonary hypertension?

Tracheobronchial disease (chronic bronchitis) Interstitial lung disease (idiopathic pulmonary fibrosis) Upper airway obstruction (brachycephalic airway syndrome) Low inspired PO2 (high altitude)

What are usually the causes of of thrombin/embolic disease leading to pulmonary hypertension?

Thrombus or thromboembolism due to hypercoagulable state (hyperadrenocortisim, pancreatitis, protein losing disease, IMHA) Cardiac (endocarditis) Non-thrombic emboli (heartworm/neoplasia)

What is the signalment of pulmonary hypertension?

Dogs >> cats Middle age-older Small breed

What are the clinical signs of pulmonary hypertension and what cardiac disease has a similar presentation and signalment?

``` Exercise intolerance Cough Tachypnea Dyspnea Syncope or pre-syncope Ascities if R CHF is present ``` Mitral valve disease

T/F: pulmonary systolic pressures greater than 30mmHg is abnormal but you usually dont see symptoms until pressures are significantly increased (greater than 80mmHg)

True

T/F: patients with severe pulmonary hypertension may have systemic HYPOtension

True

In mild/moderate PH, there may not be exam findings due to the PH, but there may be abnormalities due to the underlying dz. What might you find?

Dyspnea/tachypnea Abnormal lung sounds (crackles, wheezes, and increased BV sounds) HR normal to increased Temperature is usually normal Cyanosis Murmur due to tricuspid regurgitation (PMI right apex)

What diagnostics do you do to evaluate an underlyyting cause of PH?

Minimum database Heart-worm test Thoracic radiographs Echo is the gold standard for diagnosis of PH in small animals

What would you see on radiographs of an animal with pulmonary hypertension ??

Pulmonary infiltrates Sternal contract due to right ventricular enlargement Dilated pulmonary artery

What is the treatment of pulmonary hypertension?

Underlying cause Vasodilator drugs -sildenafil -> phosphodiesterase V inhibitor is most common in small animals -supplemental oxygen also dilates pulmonary arteries, PO2<70mmHg - pimobendan—>vasodilator effects - antithrombic therapy in cats

What is the prognosis of PH?

Fair- good: if underlying cause can be treated Poor: severe cases Sudden death can occur in severe PH Can also develop R-CHF and low output HF

What is a pulmonary thromboembolism ?

Obstruction of the pulmonary artery by a thrombus that originated in systemic venous circulation

What is Virchow’s triad for thrombus formation?

Hypercoagulability Endothelial injury Blood stasis

What conditions are associated with PTE?

Immune melted hemolytic anemia Protein losing nephropathy/enteropathy (loss of antithrombin III) ``` Neoplasia Pancreatitis Diabetes mellitus Hyperadrenocortisim Sepsis R-sided cardiac disease HWD Surgery Trauma ```

What clinical signs are seen due to PTE?

ACUTE ``` Dyspnea/tachypnea Lethargy Cyanosis Syncope, cough TR murmur if severe PH has developed ``` Symptoms related due to co-morbidities

Definitive diagnosis of PTE requires ??

CT, angiography, or radionuclide ventilation/perfusion scan

T/F: thoracic radiographs, or prothrombin (PT) time cannot definitively diagnose PTE but provide supporting evidence to the diagnosis

True

Thoracic radiographs can often appear normal in PTE, but what signs might be seen due to PTE?

Focal interstitial/alveolar infiltrates Lung lobe consolidation - a hypovascular area/lobe would be fairly specific for PTE

What are the goals of treatment of PTE?

Prevent growth of existing thrombi and prevent formation of new thrombi Support respiratory and cardiovascular system

What are the initial/acute treatments for PTE?

Anticoagulant therapy with unfractionated heparin or low molecular weight heparin (LMWH) Supplemental oxygen IV fluid therapy to optimize tissue perfusion

What is the therapy for chronic PTE?

Minimize antithrombic drugs Minimize endothelial injury Minimize blood stasis

What are the anticoagulant drugs?

Unfractionated heparin LMWH (SC)

What are the antiplatelet drugs?

Clopidogrel | Aspirin