Luis A. Sanchez

Initial experience with transluminally placed endovascular grafts for the treatment of complex vascular lesions.

Objectives Complex arterial occlusive, traumatic, and aneurysmal lesions may be difficult or impossible to treat successfully by standard surgical techniques when severe medical or surgical comorbidities exist. The authors describe a single centers experience over a 2½‐year period with 96 endovascular graft procedures performed to treat 100 arterial lesions in 92 patients. Patients and Methods Thirty‐three patients had 36 large aortic and/or peripheral artery aneurysms, 48 had 53 multilevel limb‐threatening aortoiliac and/or femoropopliteal occlusive lesions, and 11 had traumatic arterial injuries (false aneurysms and arteriovenous fistulas). Endovascular grafts were placed through remote arteriotomies under local (16 [17%]), epidural (42 [43%]), or general (38 [40%]) anesthesia. Results Technical and clinical successes were achieved in 91% of the patients with aneurysms, 91% with occlusive lesions, and 100% with traumatic arterial lesions. These patients and grafts have been followed from 1 to 30 months (mean, 13 months). The primary and secondary patency rates at 18 months for aortoiliac occlusions were 77% and 95%, respectively. The 18‐month limb salvage rate was 98%. Immediately after aortic aneurysm exclusion, a total of 6 (33%) perigraft channels were detected; 3 of these closed within 8 weeks. Endovascular stented graft procedures were associated with a 10% major and a 14% minor complication rate. The overall 30‐day mortality rate for this entire series was 6%. Conclusions This initial experience with endovascular graft repair of complex arterial lesions justifies further use and careful evaluation of this technique for major arterial reconstruction.

Endovascular graft repair of ruptured aortoiliac aneurysms.

BACKGROUND The feasibility of endovascular graft (EVG) repair of ruptured aortoiliac aneurysms (AIAs) has yet to be demonstrated. There are inherent limitations in EVG repair, including the need for preoperative measurements of the aneurysmal and adjacent arterial anatomy to determine the appropriate size and type of graft and the inherent delay to obtain proximal occlusion. We developed an EVG system with broad versatility that largely eliminates these problems. STUDY DESIGN Between 1993 and 1998, within an experience of 134 endovascular AIA repairs, 12 ruptured AIAs were treated using EVGs that facilitated intraoperative customization and eliminated the need for preoperative measurements. The EVGs consisted of either a Palmaz stent and a PTFE graft deployed by a compliant balloon (n = 9) or a self-expanding covered stent graft (n = 3). Both grafts were cut to the appropriate length intraoperatively. The mean age of the patients was 72 years (range 40 to 86 years). The mean size of the aneurysms was 7.6 cm (range 3 to 16 cm). Preoperative symptoms were present in all patients and included abdominal or back pain (n = 9), syncope (n = 4), and external bleeding (n = 2). All patients were high surgical risks because of comorbid disease (n = 10) or previous abdominal operations (n = 6), and nine experienced hypotension. RESULTS All EVGs were inserted successfully and excluded the aneurysms from the circulation. The mean operating time was 263 minutes, the mean blood loss was 715 mL, and the mean length of hospital stay was 6.5 days. There were two deaths (16%), one from the preexisting acute myocardial infarction and one from multiple organ failure. There were three minor complications (25%). Two patients required evacuation of an intraabdominal hematoma from the initial rupture. All but one of the grafts was functioning at a mean followup of 18 months. CONCLUSIONS This study demonstrates the feasibility of EVG repair for ruptured AIAs using a graft that can be customized intraoperatively for each patient. Such repairs currently are valuable in patients with ruptured AIAs and serious comorbidities and may be applicable in other circumstances as well.

Endovascular Graft Repair of Penetrating Subclavian Artery Injuries

PURPOSE Penetrating subclavian arterial injuries are often difficult to treat. Standard surgical techniques require wide exposure and dissection in traumatized areas, which is often challenging. This report summarizes the early results of endovascularly placed stented grafts for the treatment of penetrating subclavian arterial trauma. METHODS Six patients with penetrating injuries of the subclavian artery had stented grafts inserted to repair five pseudoaneurysms and one arteriovenous fistula. The stented grafts consisted of a polytetrafluoroethylene graft sutured over a balloon-expandable Palmaz stent. The devices were inserted from an ipsilateral brachial arteriotomy and deployed using fluoroscopic guidance in the operating room. RESULTS Immediate success was obtained in all procedures (100%). All patients continue to have patent grafts with a follow-up ranging from 7 to 30 months (mean 19 months). The only procedure-related complication was the need for a brachial artery patch angioplasty at the site of device insertion in the first patient. There was one other patient who developed a stent fracture at 8 months; a second stent was inserted. Duplex studies up to 24 months later show no recurrence in this patient. CONCLUSIONS Endovascular stented grafts offer an effective, less invasive alternative to standard techniques in treating traumatic arterial lesions. Early results are encouraging, but long-term follow-up will be necessary to fully delineate the effectiveness of this technique.

Transfemoral Endovascular Repair of Iliac Artery Aneurysms

PURPOSE This report evaluates the application of transfemoral endovascular repair of iliac artery aneurysms. PATIENTS AND METHODS Over a 20-month period, 11 patients with serious comorbid illnesses and a total of 14 iliac artery aneurysms were treated with endovascular grafts composed of polytetrafluoroethylene conduits combined with balloon expandable iliac artery stents (Palmaz). Nine right common, 3 left common, and 2 right internal iliac artery aneurysms were treated. The patients were men between 58 and 89 years of age (mean 72). Eight patients had isolated aneurysms and 3 had multiple iliac artery aneurysms. RESULTS Endovascular iliac grafts were successfully placed in all 11 patients. No procedural deaths occurred. Follow-up ranged from 3 to 21 months (mean 11). No acute or late graft thromboses occurred. CONCLUSIONS Transluminally placed endovascular stented grafts can be used to successfully exclude iliac artery aneurysms from the circulation while maintaining lower-extremity arterial perfusion. However, longer follow-up in more patients is necessary to confirm the durability of this technique.

Transfemoral endovascular stented graft treatment of aorto-iliac and femoropopliteal occlusive disease for limb salvage

BACKGROUND Endovascular stented grafts employ a new technique that blends intravascular stent and prosthetic graft technologies. These devices may be used to treat arterial aneurysms, occlusive disease, and vascular injuries. This report describes the application of stented grafts to the treatment of limb-threatening ischemia secondary to occlusive disease of the aorta, iliac, and femoral arteries. METHODS Three patients with limb-threatening ischemia and severe comorbid medical illnesses were treated with transvascular stented grafts that were composed of 6-mm thin-walled polytetrafluoroethylene grafts and Palmaz balloon expandable stents. The grafts were inserted through a cutdown in an artery remote from the site of occlusion and introduced into the vascular system within 14-Fr introducer sheaths. RESULTS Technical success was documented in all three patients with restoration of arterial continuity following stent graft deployment. Patency and limb salvage has been achieved to 1 year. One patient required further dilatation of the proximal stent at 6 weeks. Complications were limited to an iliofemoral deep vein thrombosis in one patient. CONCLUSIONS Endovascular stented grafts can be inserted to treat limb-threatening ischemia. Although these initial results are encouraging, greater experience in more patients observed for longer periods of time is necessary before this technique can be advocated for widespread use.

Can duplex scan arterial mapping replace contrast arteriography as the test of choice before infrainguinal revascularization

PURPOSE Arteriography is the diagnostic test of choice before lower extremity revascularization, because it is a means of pinpointing stenotic or occluded arteries and defining optimal sites for the origin and termination of bypass grafts. We evaluated whether a duplex ultrasound scan, used as an alternative to arteriography, could be used as a means of accurately predicting the proximal and distal anastomotic sites in patients requiring peripheral bypass grafts and, therefore, replace standard preoperative arteriography. METHODS Forty-one patients who required infrainguinal bypass grafts underwent preoperative duplex arterial mapping (DAM). Based on these studies, an observer blinded to the operation performed predicted what operation the patient required and the best site for the proximal and distal anastomoses. These predictions were compared with the actual anastomotic sites chosen by the surgeon. RESULTS Whether a femoropopliteal or an infrapopliteal bypass graft was required was predicted correctly by means of DAM in 37 patients (90%). In addition, both anastomotic sites in 18 of 20 patients (90%) who had femoropopliteal bypass grafts and 5 of 21 patients (24%) who had infrapopliteal procedures were correctly predicted by means of DAM. CONCLUSION DAM is a reliable means of predicting whether patients will require femoropopliteal or infrapopliteal bypass grafts, and, when a patient requires a femoropopliteal bypass graft, the actual location of both anastomoses can also be accurately predicted. Therefore, DAM appears able to replace conventional preoperative arteriography in most patients found to require femoropopliteal reconstruction. Patients who are predicted by means of DAM to require crural or pedal bypass grafts should still undergo preoperative contrast studies to confirm these results and to more precisely locate the anastomotic sites.

Midterm experience with the endovascular treatment of isolated iliac aneurysms

PURPOSE This report describes our 5-year experience with the endovascular repair of isolated iliac aneurysms and pseudoaneurysms. METHODS Between June 1993 and July 1998, 40 isolated iliac aneurysms and pseudoaneurysms were treated with endovascular grafts in 39 patients. Thirty-seven aneurysms were treated with endovascular grafts composed of polytetrafluoroethylene grafts and balloon expandable stents, and the other three underwent repair with a polycarbonate urethane endoluminal graft. RESULTS All the patients underwent initially successful endovascular treatment of isolated iliac aneurysms and pseudoaneurysms and were followed from 1 to 51 months (mean, 18 months). The 4-year primary patency rate was 94.5% +/- 10%. The perioperative complications included one episode of distal embolization, an episode of colonic ischemia, five episodes of kinking or compression of the endovascular graft, and one early postoperative graft thrombosis. There was only one perioperative death in a patient whose aneurysm ruptured in the operating room just before endovascular repair. The median postoperative length of hospital stay was 3.0 +/- 1.3 days in this group of patients at moderate and high risk. The long-term complications included one graft thrombosis and two endoleaks. One small endoleak was followed until the patient died of unrelated causes, and the other one led to aneurysm rupture in the only patient temporarily lost to follow-up examination. This patient successfully underwent treatment in the standard open surgical fashion. To date, all the other aneurysms have remained stable or have decreased in size during the follow-up examinations with duplex or contrast-enhanced computed tomographic scans. CONCLUSION Endovascular repair of iliac aneurysms and pseudoaneurysms is a safe and effective technique with good midterm results in patients at standard and high risk. These grafts are particularly beneficial for patients with medical, surgical, or anatomic contraindications for open surgical repair.

Saphenous vein biopsy: A predictor of vein graft failure***

PURPOSE To determine why some vein grafts fail, we prospectively studied the relationship between the histologic condition of the greater saphenous vein (GSV) at the time of grafting and subsequent stenosis of the vein graft. METHODS Ninety-four remnant segments of GSVs were obtained at the time of infrainguinal bypass in 91 patients and were perfusion fixed before histologic and ultrastructural examination. All bypass grafts were evaluated clinically and by duplex ultrasonography at regular intervals from 1 to 30 months after operation. All 24 grafts that developed lesions that caused thrombosis (failed grafts) or flow reduction (failing grafts) underwent arteriography and appropriate operative or other interventional correction of the causative lesion. RESULTS There was no significant difference in the incidence of coronary artery disease, kidney disease, hypertension, or history of smoking in patients with normally functioning and failed or failing grafts. Diabetes occurred with an increased frequency in failed or failing grafts (p = 0.056). At the time of their insertion, GSVs that subsequently developed significant lesions had thicker walls (0.72 +/- 0.33 mm) compared with normally functioning grafts (0.58 +/- 21 mm; p < 0.02). Most of this difference was related to a significantly thicker intima (0.27 +/- 0.17 vs 0.11 +/- 0.7 mm; p < 0.0001). Another significant finding was the presence of subendothelial spindle-shaped cells greater than five cell layers thick. This occurred more often in pregraft biopsies from grafts that developed significant lesions (70.4% vs 7.5%, p < 0.0001). Electron microscopic examination of these cells demonstrated a subpopulation of poorly differentiated cells with few fibers and many vesicles. Four of 24 (17%) failed or failing grafts had evidence of vein wall calcification at the time of vein grafting. This was seen in only one (1.4%) of 70 normally functioning grafts without lesions (p < 0.005). CONCLUSIONS We conclude that GSVs with thick and calcified walls or hypercellular intima at the time of grafting are at increased risk of developing intragraft lesions that may lead to graft failure. Frequent duplex ultrasonography surveillance is particularly warranted for such high-risk grafts.

Is percutaneous balloon angioplasty appropriate in the treatment of graft and anastomotic lesions responsible for failing vein bypasses

We reviewed 95 cases of vein graft and anastomotic lesions treated with percutaneous transluminal balloon angioplasty (PTA) and 30 cases treated surgically. The therapy was deemed a failure if the lesion recurred or if the graft closed. The 21-month patency rate of lesions treated surgically was 86%, which was significantly better than the 42% patency rate for all lesions treated with PTA (P < 0.01). An evaluation of the lesion and graft characteristics that could influence the patency of stenotic lesions treated with PTA included: lesion length, minimum graft diameter, lesion location, and lesion type. The 66% patency rate at 24 months for the 41 simple lesions (single, nonrecurrent, < 15 mm in length, and within grafts > or = 3 mm minimal diameter) was significantly better than the 17% patency rate for the 50 complex lesions (multiple, recurrent, > or = 15 mm in length, or within grafts < 3 mm in minimal diameter) (P < 0.01). In addition, the 21-month patency rate for the surgically treated group (86%) was not significantly better than that of the angioplasty-treated simple lesions (66%). When feasible, vein graft lesions are best treated with simple surgical interventions. PTA can be useful to maintain the patency of severely compromised grafts prior to surgical repair, to treat simple lesions difficult to reach surgically, and for patients with medical contraindications for an operation.

An experimental model for the acute and chronic evaluation of intra-aneurysmal pressure.

Purpose: To develop an animal model for the acute and chronic monitoring of pressure within abdominal aortic aneurysms (AAAs) to be treated with endovascular grafts. Methods: A strain-gauge pressure transducer was placed within an AAA created from a prosthetic vascular graft. Prosthetic aneurysms were implanted into 17 canine infrarenal aortas. The intra-aneurysmal pressure was monitored and correlated with noninvasive forelimb sphygmomanometry for 2 weeks. After this time, an intravascular manometer catheter was passed into the aneurysm. Simultaneous pressure measurements were obtained using the implanted strain-gauge pressure transducer, the manometer catheter, and the forelimb sphygmomanometer. Angiography was performed to assess intraluminal morphology, aneurysm anastomoses, and adjoining aortic vessels. In addition, two control animals underwent intra-aneurysmal pressure monitoring after standard surgical aneurysm repair. Results: There was excellent correlation (r = 0.97) between the pressure measurements obtained with the implanted strain-gauge pressure transducer and the intravascular manometer. Close correlation was also observed between the implanted strain-gauge transducer and the forelimb sphygmomanometer (r = 0.88) during postprocedural monitoring. Intra-aneurysmal pressure was lowered dramatically by surgical exclusion (aneurysm: 15/5 ± 7/4 mmHg; systemic: 124/66 ± 34/17 mmHg; p < 0.001). The prosthetic aneurysms were successfully imaged with angiography. Conclusions: This animal model provides an accurate and reproducible means for measuring intra-aneurysmal pressure on an acute and chronic basis. It may be possible to use this model in the assessment of endovascular devices to determine their efficacy in reducing intra-aneurysmal pressure. Evaluation of complications associated with their use, such as patent aneurysm side branches, perigraft channels, and perianastomotic reflux, may also be possible.