Exam 1: Treatment of Pulmonary Hypertension

what are the proposed clinical classification groups for PH

• pulmonary arterial hypertension

• PH due to left heart disease

• PH secondary to respiratory diseases, hypoxia, or both

• pulmonary emboli/thrombi/thromboemboli

• parasitic disease

• PH with multifactorial or unclear mechanisms

what are causes of pulmonary hypertension

• heartworm disease

• idiopathic

• drugs/toxins

• valvular disease/CDVD, valvular endocarditis

• tracheal or mainstem bronchial collapse

• diffuse pulmonary neoplasia

• bronchiolar disorders

• chronic exposure to high altitues

• chronic obstructive airway disroders

• pulmonary thromboembolism

• congenital cardiac shunts

• angiostrongylus infection

what are the categories of treatment

• strategies to decrease risk progression or complications

• targeting underlying diseases or contributory factors

• PH specific treatments

what are your strategies to decrease risk progression or complications

• exercise restriction

• prevention of contagious respiratory pathogens with vaccination and parasite prevention

• avoidance of pregnancy

• avoidance of high altitude and air travel

• avoidance of nonessential wellness procedures and elective surgery requireing GA

what is your approach for group 1 (PAH) with targeting underlying or contributing factors

• shunt closure or occlusion for L-R flow

• periodic phlebotomy, hydroxyurea for R-L flow with erythrocytosis and clinical signs

what is your approach for group 2 (left heart disease) with targeting underlying or contributing factors

• treat the LHD

• lower LA pressures

• treat CHF

  • PDE-5 NOT RECOMMENDED AS FIRST LINE

what is your approach for group 3 (secondary to resp dz, hypoxia, or both) with targeting underlying or contributing factors

• weight loss if necessary

• improve air quality

• reduce recognized triggers of clinical signs

• cough suppression

• supplemental oxygen

• control secondary infection and inflammation

• corticosteroids for inflammatory dz

• pulmonary neoplasia- contact onco

• fibrotic lung dz has no effective treatments

what is your approach for group 4 (pulmonary emboli/thrombi/thromboemboli) with targeting underlying or contributing factors

• anthithrombotic medications

  • antiplatelet agents = clopidogrel, aspirin

  • heparin products- enoxaparin, unfractionated heparin

  • factor Xa inhibitors - apixaban, rivaroxaban

what is your approach for group 5 (parasites) with targeting underlying or contributing factors

• treatment focused on management of heartworm disease and angiostrongylosis

what is your approach for group 6 (multifactorial or unclear) with targeting underlying or contributing factors

identify and address individual pathology when possible

what is the MOA of nitric oxide, endothelin, and prostacyclin

target the pathways that lead to excessive pulmonary arterial vasoconstriction as a result of pulmonary endothelial insults

what is the MOA of phosphodiesterase 5 inhibitors

• first line treatment in dogs

• target and augment vascular resistance

describe PDE-5i

• cGMP enhances vascular relaxation

• cGMP is rapidly inactivated by PDE

• PDE-5is are used to block the inactivation of cGMP to increase pulmonary artery vasodilation and decrease pulmonary vascular resistance

what are the PDE-5is used in vet medicine

sildenafil- q8hr

tadalafil- q24

how are PDE-5i used in group 1

generally recommended

how are PDE-5i used in group 2

• may cause acute pulmonary edema by increasing right heart cardiac output, acutely increasing pulmonary venous return to left atrium, subsequently increasing left atrial, pulmonary venous, and pulmonary capillary pressures

how are PDE-5is used in groups 3-6

used in addition to underlying causes if possible