Elkouri, Stéphane

Strict morphologic criteria must be used for patient selection to achieve durable success with endovascular aortic aneurysm repair (EVAR). The goal of this study was to assess morphologic suitability (MS) of abdominal aortic aneurysms (AAAs) for 2 currently approved bifurcated stent grafts and identify reasons for exclusion from EVAR. The authors reviewed the electronic charts of 1,795 consecutive patients who were diagnosed as having AAA between January 1999 and July 2001 at their institution. Three hundred and twenty patients had an AAA with a diameter of =5.0 cm, measured on computed tomography (CT). The records of 301 patients, 254 men, 47 women, with a mean age of 74 years were available for review, and these patients constituted the study cohort. Criteria used for MS included a proximal neck length =15 mm; neck diameter between 18 and 26 mm; neck angulation =60°; common or external iliac artery (CIA or EIA) diameters of 7–16 mm and 8–13 mm, respectively, for AneuRx (Medtronic Ave, Santa Rosa, CA) and Ancure (Guidant Cardiac and Vascular Division, Menlo Park, CA) bifurcated grafts. AAAs were suitable for AneuRx device in 14% of patients (43 of 301; 95% CI = 11–19%) and for Ancure in 5% (16 of 301; 95% CI = 3.1–9%). The main reason for exclusion was an inadequate proximal aortic neck (73%). The neck was too short in 49.5%, too wide in 64% and badly angulated in 12% of the patients. Iliac artery morphology precluded EVAR with AneuRx and Ancure devices in 52% and 80%. Both CIAs were too wide for EVAR in 43% and 77%, respectively. When iliac artery diameter =20 mm was accepted, iliac suitability for AneuRx increased from 49% to 70% and overall suitability increased from 14% to 20%. When more permissive criteria were used for MS (neck length =10 mm, neck diameter =30 mm, CIA =20), 39% of patients became candidates for EVAR. More than three fourths of the patients with an AAA =5.0 cm in size, seen in a tertiary referral center, are morphologically not suitable for EVAR using 2 currently approved bifurcated endografts. The main reasons for exclusion are a short or wide proximal aortic neck. Considerable changes in size of the devices and in proximal attachment techniques have to occur before most AAAs will be suitable for EVAR.

Widespread applications of totally laparoscopic aortic reconstructions have been limited by the long cross-clamp time required to suture the aortic anastomosis despite improvement in instrumentation. The authors' hypothesis was that a “one-step anastomosis concept” using an intraluminal stapler would allow shorter cross-clamp time but similar patency and imperviousness as videoscopic suturing techniques. An intraluminal stapler (Endopath-ILS, Ethicon) with a modified anvil was used to perform videoscopic-assisted thoracic aorta-to-iliac artery bypass with a 21 mm by 8 mm polytetrafluoroethylene (PTFE) graft in 22 sheep through a minimally invasive approach using a 5 cm thoracotomy. The graft-to-iliac artery anastomoses were hand sutured through a flank incision. Twelve sheep were used to establish the technique and 10 subsequent animals constituted the study group. Aortic cross-clamp time, imperviousness, and need for additional sutures were recorded and compared to previously reported data using videoscopic suturing in pigs. Patency was assessed by comparing lower limb arterial pressures. Macroscopic and microscopic examinations of the anastomoses were performed at different time-points within the first 3 months. Videoscopic-assisted stapled anastomoses were also performed on atherosclerotic aortas of 3 human cadavers. Stapled anastomoses between the thoracic aorta and PTFE graft were completed in 8 of 10 animals. Two animals were euthanized after stapler failure and anastomotic bleeding. Sutures to strengthen the anastomosis had to be used in 4 cases. Mean aortic cross-clamp time in 8 successful cases was 4.3 ±2.9 minutes (range 2–11 minutes) and was significantly shorter than clamp time of videoscopic suturing technique (48.7 ±9.4 minutes, p<0.0001). Imperviousness was good or excellent in 4 animals and fair in 4 animals. All anastomoses were patent at the end of the procedure. Examination of the anastomosis of the 2 failed interventions showed medial aortic tear surrounding the anastomosis in 1 case and misfired staples in the other. No graft occlusion was noted during follow-up ranging from 0 to 12 weeks. At the time of harvest, no bleeding was noted after epinephrine and volume infusion to increase mean arterial pressure to 200 mm Hg for 15 minutes. Macroscopic examination of the anastomoses revealed adequate healing with circumferential stapling of the prosthesis to the aortic wall and no stenosis or thrombus except in 1 false aneurysm (1/7, 14%). Surface electron microscopy showed cells coverage of the anastomosis surface. When applied on human cadaver thoracic and abdominal aorta with atherosclerotic changes, clamping times of less than 5 minutes were achieved. However, imperviousness tested with saline was poor. An automatic stapling device allows performance of a graft-to-aorta anastomosis through a minimally invasive approach with shorter clamping time than a videoscopic suturing technique. However, the current technique of aortic stapling is unreliable and further improvements are needed.

Videoscopic surgical techniques have been developed to reduce morbidity of open aortic reconstructions. The advantage of hand-assisted laparoscopic surgery (HALS) technique is the introduction of the surgeon's hand into the peritoneal cavity. The aims of this study were to assess the feasibility and to examine the learning curve, limitations, and pitfalls of the HALS technique to perform aortic reconstruction in a porcine model for training purposes. HALS aorto-aortic 8 mm polytetrafluoroethylene (PTFE) interposition grafts were placed in 12 pigs. Proficiency was judged by measuring operative time points, satisfactory completion of the operation, and the need to convert to open procedure. The strength of the relationship between order number in which a procedure was performed and the various surgical time point measures was described with the Spearman rank correlation. HALS aortic grafting was successful in the last 8 pigs. The first 2 pigs required conversion to open repair, and the graft of the third and fourth animals occluded early. Median operative time was 115 minutes (range: 75 to 205), median intestinal retraction time was 28 minutes (range: 10 to 40), median aortoiliac dissection time was 30 minutes (range: 20 to 60), and median aortic cross-clamp time was 48 minutes (range: 35 to 82). The Spearman rank correlations and p values between the order of the procedure and the intestinal retraction time, aortoiliac dissection time, clamping time, and total operative time were –0.62 (0.06), –0.47 (0.17), –0.69 (0.03), and –0.83 (0.03), respectively. HALS facilitates intestinal retraction and completion of laparoscopic aortoiliac dissection. It offers adequate exposure in pigs for aortic grafting and allows open sutured aortic anastomosis. The learning curve for HALS aortic surgery in a porcine model is short and within reach of surgeons with standard laparoscopic surgery skills, since no laparoscopic suturing is required. Training on this porcine model may be an efficient and safe way to introduce surgeons to HALS for aortoiliac reconstruction.