AAA Endovascular Repair Dr. Peters

Endovascular AAA Repair: The what, how, and why. David C. Peters, MD Abdominal Aortic Aneurysms: • Mortality of rupture – outside hosp.: 90% – inside hosp.: 50% • 15,000 deaths/yr AAA’s- Size does matter: • Increase 0.5-1cm/yr • Risk of rupture: – 5 cm= 25% over 5 yrs – 7 cm= 75% over 5 yrs Endovascular vs. open: Endovascular vs. open (cont.): • • • • Post-op pain (minimal vs. significant) Impaired pulmonary function No retroperitoneal dissection No aortic cross-clamp Respiratory Function Post-Op Br J Surg, 84(1S), May 1997. Endo AAA Repair: Pre-op preparation • Same as open • GA vs. Epidural vs. local (?) • lg peripheral IV, Aline, central line • mortality 2-5% Preparation (cont.): • T&C (? blood in room) • Temperature!!! – conduction, convection, radiation, evaporation • Anesthesia machine checked/ready Endovascular AAA repairWhat happens in the fluoroscopy suite: • Std monitors, + foley, + a-line, ST segments • prepped chest to knees • both groins accessed – cut-down for 8fr, percutaneous for 12fr • capability to monitor ACT Available grafts: • 3 types (tube, bifurcated and aortoiliac) • min. 1.5 cm below renal arteries Placement of graft: • Surgical goal: – exclusion of aortic aneurysmal sac from systemic circulation with no restriction of renal arteries. Placement of the graft (cont.): • Heparinization • Measurements taken • Superior portion of graft positioned • Deployment Deployment = Ao X-clamp: Goal= prevent migration • induced hypotension (MAP=50-60mm Hg) – anesthetics – vasodilators • temporary asystole – adenosine – VF (?) Induced Ventricular fibrillation to facilitate endovascular stent placement. Anes 88:1998. High Dose Adenosine: High Dose Adenosine: • 100 patients • goal= asystole for “at least” 10s • dose range 12-90mg (median 24mg) High Dose Adenosine (cont.): • • • • 2 patients- myocardial ischemia 2 patients- Atrial fibrillation 1 patient- new bundle branch block 4 patients- required activation of pacemakers High Dose Adenosine (cont.): Conclusion: “The perioperative use of high dose adenosine to ensure precise stent-graft placement appears to be a safe method of inducing temporary asystole…” Endovascular AAA tube graft: Bifurcated Grafts: Endovascular AAAPitfalls: • Hypothermia – coagulopathy – shivering Endovascular AAAPitfalls: • Hemorrhage – average = 200-300. BAMC record >2 L – difficult to monitor Endovascular AAAPitfalls: • Emergency conversion to open procedure • Thrombosis • Graft migration Endovascular AAA Repair Large, multi-center study-1023 patients with >=12 month follow-up – 18% required secondary intervention – Freedom from intervention at 1,3, and 4yrs were 89%, 67%, and 62% Br J Surg 87(12): Dec 2000. Endovascular AAA Repair “The high incidence of late secondary interventions is a cause for concern with regard to broad application of endovascular AAA repair, and emphasizes the need for life long surveillance.” Br J Surg 87(12): Dec 2000.