ABDOMINAL AORTIC ANEURYSM. .pptx

By supraja

1. ABDOMINAL AORTIC ANEURYSM Dr.g supraja 2 nd yr post graduate Dept of general surgery

2. Abdominal aortic aneurysm DEFINITION Abnormal permanent focal or localized dilatation of a segment of aorta with increase in size of more than 50% of the normal arterial diameter. Incidence -3-10% Most common - Infra renal Normal values may vary based on methods of measurement, patient’s age, gender, and other factors

3. WANNHEIM ET AL MEN WOMEN ASCENDING AORTA 4.7 CM 4.2 CM DESCENDING AORTA 3.7 CM 3.3 CM INFRA RENAL AORTA 3.0 CM 2.7CM

4. CLASSIFICATION Wall structure True aneurysm Pseudoaneurysm

5. SHAPE Fusiform Saccular

6. PRESENTATION Asymptomatic Symptomatic Complicated Uncomplicated

7. ETIOLOGICAL Degenerative (most common) Infective Inflammatory Connective tissue disorders Traumatic

8. PATHOLOGY Weakening of the arterial wall and increased local hemodynamic forces contribute to development of aneurysm "Staccato" pattern of growth. Average growth of 3-4 mm/ yr Larger the initial diameter- faster is the growth. Marfan syndrome, familial thoracic aortic aneurysm and dissection, and vascular-type Ehlers Danlos syndrome

9. Matrix metalloproteinases and proteolytic enzymes in wall of aorta Degradation of extracellular matrix Reduction of elastin concentration Role of matrix metalloproteinases and deficiency of anti proteolytic enzymes

10. PRESENTATION Majority are asymptomatic Symptomatic AAA Back pain Abdominal pain Pulsatile mass per abdomen

11. INVESTIGATIONS USG - good in AAA assessment CE US abdomen - EVAR screening post op IVUS - intra op assessment CT - best in diagnosing and surveillance when in doubt, perform CT Angiography MRI - best alternative - no radiation/contrast

12. WHEN TO INTERVENE Risk of aneurysm rupture exceeds risk of all cause of death in the patient - Intervention is warranted - PROPHYLACTIC INDICATIONS OF REPAIR OF ANEURYSM Depending upon of diameter of aneurysm Rate of progression >0.5cm/ yr Complications of AAA

13. COMPLICATIONS Rupture Thrombosis Embolism Aortocaval fistula Aortoenteric fistula Erosion of vertebra Spinal cord ischaemia

14. SCREENING One time screening for all men of age above 65yrs and men above 55yrs with h/o AAA in family. USPSTF - one-time screening for AAA using ultrasonography of men between 65 and 75 years of age who have a smoking history Selective screening for nonsmokers Not for women AAA patients without appropriate surveillance - sixfold increase in rate of rupture Once abdominal aortic aneurysm is detected, USG follow up is advisable

15. SCREENING (Society for Vascular Surgery clinical practice council)

16. MANAGEMENT MEDICAL For aneurysms that do not meet criteria for surgical intervention, medical management is main stay of treatment. Lifestyle modifications such as Tobacco cessation. Cessation of smoking [ since it has an expansion rate of AAA (∼ 0.4 mm/ yr ) ] Moderate exercise has a beneficial impact on progression of atherosclerosis.

17. Blood pressure management. Marfan syndrome treated with β-blockers, angiotensin II receptor blockers, and angiotensin-converting enzyme inhibitors. HMG–coenzyme A reductase inhibitor (statin) therapy - reduced rates of AAA enlargement and decrease in the incidence of major cardiovascular events Antiplatelet therapy using aspirin.

18. PRE OP PREPARATION CARDIAC EVALUATION- CAD is very common so is the valvular problem 2D Echo Functional Scan - Dipyridamole-Thallium Myocardial viability Cardiac angiogram for Symptomatic patients or patients with LVEF <30%

19. PULMONARY EVALUATION ABG and spirometry FEV1 and pCO2 <45mm of Hg Smoking cessation, treatment for bronchitis RENAL EVALUATION Serum Creatinine, Electrolytes, BUN Temporary Hemodialysis

20. ENDOVASCULAR ANEURYSM REPAIR (EVAR) JUAN CARLOS PARODI performed first Successful EVAR for AAA (1991). PRINCIPLE: Implantation of an aortic stent graft which is fixed proximally and distally to non aneurysmal aorto-iliac segment , thereby excluding the aneurysm from circulation .

21. PRE-REQUISITES FOR EVAR Anatomical eligibility for EVAR based on 1.Proximal aortic neck 2.Common iliac and external iliac arteries 3.Common femoral artery Secondary considerations -Mural calcifications < 50% -Luminal thrombosis < 50%

22. PLANNING OF DEVICE MEASUREMENTS OF THE GRAFT REQUIRED ARE ESTIMATED FROM Central line(over estimate) CTA (using marker catheter) Proximal diameter of the main device is oversized by 10-20% of diameter of neck. Distal limb oversized by 1-4mm.

23. PROCEDURE FEMORAL ARTERY ACCESS GUIDEWIRE ADVANCEMENT –DESCENDING AORTA SYSTEMIC HEPARINISATION INSERTION OF PRIMARY DEVICE(L1-L2)

24. INTRODUCTION OF ANGIOGRAPHIC CATHETER(L1-L2) ROAD MAPPING AORTOGRAM DEPLOYMENT OF PRIMARY DEVICE INSERTION OF DIRECTIONAL CATHETER AND ANGLED GUIDE WIRE INSERTION OF GRAFT LIMB THROUGH CONTRALATERAL ILIAC LIMB

25. CANNULATION OF MAIN DEVICE DEPLOYMENT OF CONTRALATERAL ILIAC LIMB INTO THE DOCKING OPENING OF PRIMARY DEVICE COMPLETION ANGIOGRAM (CHECK FOR PATENCY OF RENAL,HYPOGASTRIC ARTERIES,DEVICE LIMBS,PROXIMAL AND DISTAL FIXATION ,ENDOLEAKS) REPAIR OF FEMORAL ARTERY AND CLOSURE OF GROIN INCISIONS

26. ADVANTAGES Indicated in patients who are at increased risk of surgery due to age, comorbidity. Minimally invasive procedure Less hospital stay Avoids respiratory complications and prolonged ventilation Reduced GI complications

27. COMPLICATIONS Endo leak Stent graft iliac limb dysfunction Kinking of stent due to remodeling of aneurysm Progression of underlying iliac atherosclerotic lesion ultimately graft limb occlusion Treatment-thrombolysis/graft thrombectomy Renal artery occlusion-improper stent graft position/migration Graft limb separation or dislocation

28. Stent graft malfunction due to improper deployment Dislodgement of graft limb during deployment Graft stent fracture Groin hematoma Wound infection

29. POST OP SURVEILLANCE Failure to achieve good seal results in endoleak , it means that aneurysm is not excluded from circulation and aneurysm may still expand and rupture Lifelong follow up is essential with duplex scan or CT scan to detect endoleak , component disconnection, migration of stent graft. Absence of appropriate follow up is dangerous than not having an repair at all. Triple phase spiral CT scan and abdominal X-ray. Half yearly for first 2 years Yearly later

30. ENDOLEAK Definition : Extravasation of contrast outside the stent graft and within the aneurysm sac. -Incidence:20-30% -About 50% of cases resolve spontaneously within 6 months -CT is sensitive -CTA is specific

31. OPEN AAA REPAIR TRANSPERITONEAL SKIN INCISION PACKING OF BOWEL MOBILISATION OF DUODENUM-FOURTH PART THIRD PART DISSECTION OF PROXIMAL AORTA UPTO LEFT RENAL VEIN(NECK OF ANEURYSM)

32. DISTAL EXTENT UPTO NON ANEURYSMAL PORTION SYSTEMIC HEPARINISATION DISTAL LIMB CLAMP PROXIMAL LIMB CLAMP ARTERIOTOMY(RIGHT TO IMA ORIGIN) – PROXIMALLY AND DISTALLY

33. THROMBUS IS SCOOPED OUT CONTROL OF BACK BLEEDING T SHAPED ARTERIOTOMY INCISIONS PROXIMALLY AND DISTALLY INLAY ANASTOMOSIS BETWEEN GRAFT AND AORTA

34. Patient should be adequately resuscitated with fluids and pressor agents before release of clamps. Clamps should be released from one limb at one time. Drop of 10-20 mm of Hg blood pressure and rise of Endtidal CO2(EtCO2) together with palpable femoral pulses indicates the restoration of blood flow to the lower limbs.

35. CHECKLIST BEFORE CLOSURE Is colon adequately perfused Is the IMA back bleeding Have any lumbar arteries started back bleeding as distal perfusion is now restored. Are both femoral pulsations present CLOSURE (Aneurysmal sac is sutured over the graft) Peritoneum is repositioned Bowel and omentum moved towards their normal positions

36. ADVANTAGES AAA is permanently eliminated as it is entirely replaced by a prosthetic aortic graft Risk of aneurysmal recurrence or delayed rupture no longer exists Long term imaging surveillance is not needed

37. COMPLICATIONS LOCAL Postoperative bleeding Limb ischemia Colonic ischemia Spinal cord ischemia Prosthetic graft infection(1-4%) Aortoenteric fistula

38. SYSTEMIC CARDIAC - MI or arrythmias are most common RENAL - Renal failure or transient renal insufficiency RESPIRATORY- Respiratory failure

39. RUPTURED ABDOMINAL AORTIC ANEURYSM

40. RUPTURED ABDOMINAL AORTIC ANEURYSM (RAAA) Anteriorly – 20 percent – into peritoneal cavity Posteriorly – 80 percent – into retroperitoneum Operative mortality – 50% Combined mortality – 80%

41. CLINICAL PRESENTATION Always suspect a ruptured abdominal aortic aneurysm If a patient presents with Severe abdominal pain/back pain Hypotension Pulsatile mass

42. Less common symptoms Hematuria Groin hernia CHF (ruptured into vena cava)

43. RAAA may be misdiagnosed as Renal colic Perforated hollow viscus GI bleed Ischemic bowel

44. DIAGNOSIS PLAIN X-RAY Enlarged outline of calcified aortic wall Loss of psoas shadow ABDOMINAL USG Sensitive in detecting aneurysm not rupture ABDOMINAL CT (ACCURATE) Presence of retroperitoneal blood

45. Enlarged outline of aortic wall calcification

46. CT

47. PRE OPERATIVE MANAGEMENT RESUSCITATION Minimally resuscitate to maintain consciousness PERMISSIVE HYPOTENSION SBP NOT ABOVE 100mm of Hg Use blood and blood products INVESTIGATIONS Chest Xray ECG

48. SURGERY APPRAOCHES OPEN TRANSPERITONEAL OPEN RETROPERITONEAL ENDOVASCULAR

49. Patient should be painted and draped prior to induction of anaesthesia while patient is awake. Induction of anaesthesia results in abdominal muscle paralysis which leads to loss of tamponade effect.

50. SURGERY OPEN REPAIR HYPOTENSION NO HYPOTENSION SUPRACELIAC CLAMP INSPECT RETROPERITONEUM PARARENAL EXTENSIVE NO HEMATOMA HEMATOMA CAREFUL DISSECTION FOR INFRARENAL CONTROL UNCONTROLLED BLEEDING DEVELOPS

51. OPEN REPAIR-TRANSPERITONEAL Fastest and easiest Approach for supraceliac clamp

52. Identifying supraceliac part of aorta

53. Clamping supraceliac aorta

54. SUPRACELIAC CLAMP COORDINATE WITH ANAESTHESIA After clamp improve the resuscitation Before releasing clamp-prepare for hypotension ADVANTAGES Quick solution to severe hypotension Avoids injury to renal and gonadal vein from blind dissection of infrarenal neck DISADVANTAGES Ischemic injury to liver, bowel and kidneys

55. ENDOVASCULAR REPAIR Requirements Rapid CT Scan for evaluation of neck diameter, angulation and iliac size Skill of surgeon Devices Cathlab for endovascular procedure Anaesthesia - local / local and convert to GA

56. COMPLICATIONS Postoperative bleeding related to coagulopathy due to hypothermia. Abdominal compartment syndrome Multiple organ failure

57. THANK YOU 