AORTIC ANEURYSM & AORTIC DISSECTION.pptx

AORTIC ANEURYSM & AORTIC DISSECTION.pptx

1. D. P. Shiny Latha M.B.B.S., M.D.(Path) ANEURYSM & DISSECTION

2. aneurysm A localised abnormal dilation of blood vessel or the heart -congenital/ acquired

3. CLASSIFICATION (based on vessel layers)

4. CLASSIFICATION (based on morphology)

5. PATHOGENESIS To maintain structural & functional integrity, arterial walls constantly remodels by synthesizing, degrading & repairing damage to their ECM constituents Aneurysm occurs when structure or function of connective tissue within the vasculature is compromised

6. POOR CONNECTIVE TISSUE

7. MARFAN SYNDROME ANEURYSM

8. LOEYS-DIETZ SYNDROME

9. EHLERS-DANLOS SYNDROME

10. COLLAGEN DEGRADATION BY INFLAMMATION Decreased Tissue inhibitors of metalloproteases (TIMP)

11. LOSS OF SMOOTH MUSCLE CELLS OR NONCOLLAGENOUS ECM SYNTHESIS Atherosclerotic thickening of intima  increases the distance that O2 & nutrients must diffuse  Ischemia of inner media Systemic hypertension  narrowing of arterioles of vasovasorum  Ischemia of outer media

12. SYPHILITIC ANEURYSM Late stage of syphilis Obliterative endarteritis Ischemic injury of the aortic media Aneurysmal dilation

13. CAUSES OF AORTIC ANEURYSM

14. ABDOMINAL AORTIC ANEURYSM (AAA) MC- Abdominal aorta, common iliac arteries Men, smoker, rare <50yrs Below the renal arteries or above the bifurcation of aorta Usually 5cm diameter, 25 cm in length Severe complicated Atherosclerosis Destruction & thinning of aortic media Aneurysm contains bland, laminated, poorly oragnised mural thrombus

15. INFLAMMATORY AAA Young adults Back pain Elevated inflammatory markers- CRP Abundant lymphoplasmacytic inflammation with many macrophages, giant cells, dense periaortic scarring Cause : localised immune response to the abdominal aortic wall

16. IMMUNOGLOBIN G4 RELATED DISEASE High plasma levels of IgG4 & tissue fibrosis Frequent infiltrating IgG4 expressing plasma cells Affects pancreas, biliary system & salivary gland Responds well to steroid therapy

17. MYCOTIC ANEURYSM Lesions that have become infected by lodging of circulating microorganisms in the wall Suppuration  destroys the media  rapid dilation  Rupture

18. CLINICAL FEATURES Asymptomatic Discovered incidentally Abdominal mass Mimics tumor Rupture into peritoneal cavity  massive fatal hemorrhage Obstruction of vessel  ischemic injury  iliac , renal, mesenteric or vertebral arteries Embolism from atheroma or mural thrombus Impingement to adjacent structure- compression of a ureter or erosion of vertebrae

19. RISK OF RUPTURE 4 cm or less – Nil 4-5 cm- 1% 5-6 cm- 11% >6 cm – 25% Aneurysm expand at a rate of 0.2 to 0.3 cm per year

20. MANAGEMENT Surgical bypass with prosthetic grafts Timely surgery is critical Mortality of unruptured aneurysm – app. 5% Mortality of ruptured aneurysms- > 50%

21. THORACIC AORTIC ANEURYSM Respiratory difficulties- encroachment on lungs & airways Difficulty in swallowing – compression of esophagus Persistent cough- compression of recurrent laryngeal nerves Pain- erosion of bone Cardiac disease- myocardial ischemia Rupture

22. AORTIC DISSECTION

23. AORTIC DISSECTION Aortic dissection occurs when blood separates the laminar planes of the media to form a blood filled channel within the aortic wall Men ; 40-60 years with antecedent hypertension Young adults with systemic or localised abnormalities of connective tissue affecting the aorta

24. Can be Iatrogenic  arterial cannulation during coronary catheterization procedure  cardiopulmonary bypass Rare- pregnancy – during or after 3 rd trimester - related to hormone induced vascular remodelling - hemodynamic stresses of the perinatal period

25. PATHOGENESIS Systemic hypertension  narrowing of arterioles of vasovasorum  Medial hypertrophy of vasa vasorum  degenerative changes loss of smooth muscle cells & disorganised ECM Ischemic injury Inherited or acquired connective tissue disorders- Marfan syndrome, Ehlers- Danlos syndrome, defects in copper metabolism

26. PATHOGENESIS Trigger for the intimal tear & initial intramural aortic hemorrhage Intimal tear  blood flow dissects through the media progression of hematoma Sometimes, disruption of penetrating vessels of vasa vasorum  intramural hematoma without intimal tear

27. MORPHOLOGY Cystic medial degeneration Inflammation – absent Marked degenerative changes – seen at the autopsies of patients In vast cases, sponateous dissection occurs In ascending aorta- within 10cm of the aortic valve; transverse with sharp, jagged edges upto 1-5 cm in length Dissection can extend retrograde toward the heart as well as distally; sometimes into the iliac & femoral arteries

28. Dissecting hematoma spreads along the laminar planes of the aorta; between middle & outer thirds It can rupture through the adventitia  massive hemorrhage into the thoracic or abdominal cavities In some cases dissecting hematoma reenters the lumen of the aorta through the a second distal intimal tear new false vascular channels Double barelled aorta Overtime  false channels endothelialized to become chronic dissection

29. CLINICAL FEATURES Sudden onset of excruciating pain  beginning in the anterior chest, radiating to the back between the scapulae, moving downwards as the dissection progresses Confused with Myocardial infarction

30. CAUSE OF DEATH Rupture of the dissection into the pericardial, pleural or peritoneal cavities Retrograde dissection into the aortic root  disrupts the aortic valve annulus Clinical manifestation includes  Cardiac tamponade  Aortic insufficiency Dissection can extend into the great arteries of the neck or into the coronary, renal, mesenteric or iliac arteries Causing vascular obstruction & ischemic consequences- MI; spinal arteries- Transverse myelitis

31. MANAGEMENT In Type A dissection ,  rapid diagnosis & institution of antihypertensive therapy  surgical plication of the aortic intimal tear Mortality – 70% in those who present with hemorhage or symptoms related to distal ischemia 10-year survival rate : 40 to 60%

32. MANAGEMENT In Type B dissection , Conservative management  Surgery or anti-hypertensive medication 10-year survival rate : 75%