Cardio2- Vascular Diseases

  1. What is an AV fistula?
    a congenital or acquired direct communication between an artery and a vein
  2. How does an AV fistula lead to local edema?
    arterial blood (high pressure) shunts into the vein--> dramatic increase in venous pressure--> increased capillary hydrostatic pressure--> edema
  3. What is a bruit?
    continuous murmur heard over the lesion of an AV fistula (blood shunting from artery to vein)
  4. How does atherosclerosis lead to tissue ischemia? How does this explain the difference between occurrence of MI in dogs and humans?
    hardening and narrowing of arteries--> increased vascular resistance--> reduced tissue perfusion downstream--> potential for organ ischemia and injury; dogs have greater collateral circulation in their hearts and don't get MI as often as humans
  5. Describe degenerative changes of the coronaries seen in old dogs and the clinical consequences of this.
    arteriosclerosis due to subintimal or medial proliferation of glycosaminoglycans or smooth muscle--> ischemia, infarction--> fibrosis; we don't yet understand if this is of clinical importantce
  6. Medial hypertrophy of small pulmonary arteries is a common incidental finding in dogs and is associated with __(3)__; it occurs due to...
    heartworm disease, left to right shunts, and idiopathic pulmonary hypertension; increased flow into the lungs causing damage to small vessels.
  7. What is a plexiform lesion?
    obliterative endothelial cell proliferation and vascular smooth muscle hypertrophy in pre-capillary pulmonary arterioles; seen with pulmonary hypertension as a maladaptive response
  8. Vascular mineralization is a consequence of... (3)
    vasculitis, abnormal increases in calcium or phosphorous (high Ca:P product), idiopathic
  9. Mineralization of the aorta in a cow is a consequence of ________ due to ________ [specific disease].
    vasculitis; Johne's disease (Mycobacterium paratuberculosis)
  10. Describe the appearance of post-mortem blood clots as opposed to pre-mortem thrombosis.
    Post-mortem clots: dark red or fatty yellow (if RBCs sediment out after death), NOT attached to endocardial/intimal walls
  11. What are the 3 factors that play into thrombosis (Virchow's triad)?
    endothelial damage, prothrombotic state, stagnant/altered blood flow
  12. How does feline HCM lead to saddle thrombus?
    cat with HCM--> increased atrial pressure/ turbulence--> left atrial thrombus--> part breaks off and goes to terminal aorta--> aortic thromboembolism ("saddle thrombus")
  13. What are the clinical consequences of arterial thromboembolism to the distal aorta in feline cardiomyopathy? (4)
    rear limb paresis, severe pain is common from ischemia, cramping (firm muscles), rhabdomyolysis (necrosis of striated muscles)
  14. What are the principals of acute therapy for thromboembolism? (4)
    analgesia with opiates, prevent further thrombosis with heparin, tissue plasminogen activator (dissolves clots- potential for reperfusion hyperK+...pros and cons), +/- cath intervention (dogs and horses)
  15. What are the principals for chronic management of thromboembolism and prevent of aortic TE?
    • Clopidogrel (Plavix)- antiplatelet
    • Aspirin- antiplatelet COX inhibitor
  16. Contrast aortic TE in dogs and cats.
    • Dogs: usually locally formed; slow onset of paresis
    • Cats: usually embolic from atrium; sudden onset paralysis
  17. Causes of aortic TE in dogs. (2)
    protein losing disorders (loss of antithrombin), idiopathic disease
  18. Causes of aortic TE in horses. (1)
    local aortic-iliac disease [very rare]
  19. How can heartworms cause pulmonary embolism?
    adulticide therapy--> adult worms die--> obstructive leasion
  20. Causes of venous thrombosis from thrombophlebitis. (4)
    chemical irritants or drugs, catheters or physical injury, hypercoagulable states (IMHA), neoplastic invasion
  21. What are the consequences of thrombophlebitis and venous obstruction? (4)
    obstructed venous return, edema, pulmonary TE, respiratory distress/tachypnea
  22. What are the key clinical features of jugular thrombophlebitis in a horse?
    increased hydrostatic pressure upstream--> facial edema +/- parts of thrombus break off and travel downstream to right heart--> pulmonary embolism
  23. Discuss the development of a pulmonary TE in a dog with abnormal clotting and hyperthrombotic state.
    hyperthrombotic state-->systemic venous thrombus--> parts of thrombus break off and travel downstream (heart)--> get pumped into pulmonary vessels--> get lodges in small pulmonary capillaries--> pulmonary TE, tachypnea, respiratory distress
  24. Downstream consequence of venous thrombosis is __________; upstream consequence is __________.
    embolus; edema
  25. When there is edema with vasculitis, it is usually due to/associated with ___________.
    the inflammation
  26. What are potential consequences of vasculitis? (5)
    hemorrhages (due to vascular permeability changes or rupture), thrombosis (-->ischemia--> infarction), pain, impaired organ function, +/- edema
  27. What diagnostic tests are effective for recognition of intravascular thrombosis?
    increased D-dimers, CT angiogram
  28. Describe the pathogenesis of Strongylus vulgaris infection in horses.
    S. vulgaris larvae migrate to the mesenteric arteries--> cause severe damage to arteries--> arteritis and severe thickening of the arterial wall with fibrosis and smooth muscle hyperplasia
  29. Radiographically, you see a bulge in the cranidorsal cardiac silhouette of an older cat. What do you think?
    Aortoannular ectasia- dilation of the aorta across the root and into the descending aorta- can be idiopathic and incidental or may be due to systemic hypertension
  30. What is "nutmeg liver"?
    chronic passive congestion of the liver due to right heart failure- centrolobular regions are red and depressed, representing hepatocyte loss and congestion; periportal regions are yellow/tan due to fatty changes resulting from hypoxia
  31. What is lymphedema?
    abnormal accumulations of lymph related to lymphatic malformation or obstruction to drainage (congenital, infection of lymphatics)
  32. How does vasculitis lead to injury of tissues and organs? (6)
    damages vessels, causing hemorrhages, local thrombosis with ischemia +/- necrosis, edema (w/ cutaneous vasculitis), decreased blood flow to heart, gut, or skeletal muscle--> pain
  33. Sudden death in an older breeding stallion has been associated with what vascular disaster?
    • degeneration of the ascending aorta--> rupture of aorta--> bleeding into pericardial space--> cardiac tamponade OR
    • aortic sinus of Valsalva rupture--> aortic- cardiac fistula
Card Set
Cardio2- Vascular Diseases
vetmed cardio2