Pulmonary Hypertension Student PDF

Pulmonary Hypertension Kat Davros, DVM, DACVECC At the end of this lecture you should know: 1. The anatomy and pathophysiology of pulmonary hypertension 2. How the severity of PH is defined 3. Signs and symptoms of PH 4. The 6 classifications of PH 5. How to diagnose PH 6. How to tre...

Pulmonary Hypertension Kat Davros, DVM, DACVECC At the end of this lecture you should know: 1. The anatomy and pathophysiology of pulmonary hypertension 2. How the severity of PH is defined 3. Signs and symptoms of PH 4. The 6 classifications of PH 5. How to diagnose PH 6. How to treat PH Anatomy Review- Lets Label! B K F F E G G H I H C J D A What is pulmonary hypertension? Abnormally increased pressure within the pulmonary vasculature Mean pulmonary arterial pressure (PAP) > mmHg How Do We Actually Measure The PAP? - What type of diagnostic imaging allows us to evaluate the heart best? - ______________ - What valve is between the right ventricle and right atrium? - ________________ - What happens to the blood during systole in animals with PH? - _____________________________________ ____________ - We measure the ______________to give us an idea of how severe the PH might be Peak Tricuspid Regurgitation Velocity (TRVmax) - Measured by Doppler echocardiography - Estimates the systolic pulmonary artery pressure - Simplified Bernoulli equation to get Tricuspid Regurgitation Pressure Gradient (TRPG) - TRPG= 4x (TRV)2 Severity of PH Tricuspid Regurgitant Pressure Severity of PH Gradient TRPG >___mmHg Mild TRPG >___mmHg Moderate TRPG>___mmHg Severe  Pathophysiology 1. __________________ 2. __________________ __________________ __________________ __________________ MPA __________________ Pulm. Veins __________________ __________________ 3. __________________ Pulm. Capillaries __________________ __________________  Clinical Presentation - Age: - Very young, think shunts (PDA) - Old: Pulmonary fibrosis, hypercoagulable disease - Breed: - Small breed: MMVD, tracheal collapse - Brachycephalic: chronic obstructive airway disease, heart base masses - Westies predisposed to pulmonary fibrosis -If living in the south, think parasites Clinical Symptoms Suggestive of PH Possibly Suggestive of PH Strongly Suggestive of PH Tachypnea at rest Syncope Increased respiratory effort at rest Respiratory distress at rest Prolonged post-activity tachypnea Activity ending in respiratory distress Cyanotic or pale mucous membranes Right sided congestive heart failure Physical Exam Left apical murmur: MMVD Right basilar murmur: Tricuspid valve regurgitation May have crackles, Cyanosis and coughing wheezes, or increased lung secondary to airway or lung sounds if underlying lung disease disease Respiratory pattern can help identify which part of respiratory system is affected Jugular vein distension, ascites, and pleural effusion can indicate right sided failure Thoracic Radiographs Treatments  ○ Exercise restriction ○ Prevent respiratory infections and parasites ○ Avoid pregnancy and obesity ○ Avoid high altitudes and air travel ○ Avoid nonessential procedures and elective surgery requiring anesthesia For ALL PH patients, regardless of cause or severity Little different for every group. Will go through individually. Sildenafil (Viagra) Phosphodiesterase, an enzyme produced in the lungs, breaks down cGMP into inactive GMP Sildenafil decreases the enzyme's activity, so more cGMP is available to relax the arteries What Causes Pulmonary Hypertension? Group 1: Pulmonary ARTERIAL Hypertension Causes: Increased pulmonary blood flow - Congenital left to right shunts - PDA - Ventricular or atrial septal defect - Idiopathic Group 1: Pulmonary ARTERIAL Hypertension Diagnosis - Usually very loud murmurs - Thoracic radiographs, echocardiogram Group 1: Pulmonary ARTERIAL Hypertension Treatment - Close the shunt if possible - Can consider Sildenafil - May need lifelong management What Causes Pulmonary Hypertension? Group 2: PH Due to Left Heart Disease - Causes - Left ventricular dysfunction - Dilated cardiomyopathy - Valvular disease - Myxomatous mitral valve disease - Aortic stenosis Group 2: PH Due to Left Heart Disease Diagnosis - Thoracic radiographs - Left atrial enlargement - Right sided enlargement - +/- pulmonary edema - Echocardiogram - Help specify cause of left sided disease Group 2: PH Due to Left Heart Disease Treatment - Pimobendan - ACE inhibitors - +/- Furosemide - DO NOT recommend sildenafil - Will increased preload to left heart and can worsen failure What Causes Pulmonary Hypertension? Group 3: Respiratory Disease and/or Hypoxia - What is hypoxic pulmonary vasoconstriction? - Intrapulmonary arteries constrict in response to alveolar hypoxia, diverting blood to better- oxygenated lung segments - Causes - Chronic obstructive airway diseases - Tracheal or bronchial collapse - Brachycephalic obstructive airway disease - Pulmonary parenchymal disease - Pulmonary fibrosis - Infectious pneumonia - Feline asthma - Chronic high altitude exposure - Emphysema Group 3: Respiratory Disease and/or Hypoxia Diagnosis Group 3: Respiratory Disease and/or Hypoxia Simplified Diagnosis - Upper airway disease? (BOAS, Yorkie with tracheal and bronchial tracheal collapse, laryngeal collapse paralysis) - Yes: confirm with upper airway exam and treat accordingly Cat with chronic lower airway disease - No: obtain thoracic radiographs Westie with Fibrosis - Often gives you an idea of disease process - If disease not clear, can perform airway wash, culture, and/or biopsies Group 3: Respiratory Disease and/or Hypoxia Treatment - Treat underlying disease - BOAS? Surgery - Pneumonia? Antibiotics - Feline asthma? Bronchodilator and steroids - The rest? Probably steroids - Recommend sildenafil for these patients What Causes Pulmonary Hypertension?  Group 4: Thromboembolic Disease Causes - Acute or chronic pulmonary thromboembolism - Blood clot that breaks off and travels to another part of the body - Lodges in main PA-> usually die acutely - Lodges in smaller vessels-> can survive - Usually secondary to hypercoagulable states - Cushing’s, protein losing disease, neoplasia, infections Group 4: Thromboembolic Disease (better image for pathophys) - Diagnosis Group 4: Thromboembolic Disease Treatment - Treat underlying disease - Anticoagulation - Clopidogrel (anti-platelet) - Sildenafil recommended What Causes Pulmonary Hypertension? Group 5: Parasitic Disease Heartworm (Dirofilaria Immitis) Lungworm (Angiostrongylus Vasorum) Group 5: Parasitic Disease Diagnosis - Heartworm - Angiostrongylus Group 5: Parasitic Disease Treatment of Heartworms Treatment of Angiostrongylus - Follow Heartworm Society - Moxidectin or Fenbendazole guidelines - +/- steroids - Can consider sildenafil if - Can consider sildenafil if symptoms of PH are severe symptoms of PH are severe What Causes Pulmonary Hypertension? Group 6: Multifactorial - Causes - Clear evidence of 2 or more underlying group 1-5 pathologies - Masses compressing the pulmonary arteries - Other disorders with unknown mechanisms What Causes Pulmonary Hypertension? Summary Chart (Fill out on own, answers posted on ELC) Group Cause Diagnosis Treatment 1 2 3 4 5 6 Diagnosis cheat sheet (not on exam, just for help on clinics)  six six Parasites Group 6: Multifactorial