Kurt R. Wengerter

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.

Changing arteriosclerotic disease patterns and management strategies in lower-limb-threatening ischemia.

From January 1, 1974 to December 31, 1989, we treated 2829 patients with critical lower-extremity ischemia. In the last 5 years, 13% of patients had therapeutically significant stenoses or occlusions above and below the groin, while 35% had them at two or three levels below the inguinal ligament. Unobstructed arterial flow to the distal half of the thigh was present in 26% of patients, and 16% had unobstructed flow to the upper third of the leg with occlusions of all three leg arteries distal to this point and reconstitution of some patent named artery in the lower leg or foot. In the last 2 years, 99% of all patients with a threatened limb and without severe organic mental syndrome or midfoot gangrene were amenable to revascularization by percutaneous transluminal angioplasty (PTA), arterial bypass, or a combination of the two, although some distal arteries used for bypass insertion were heavily diseased or isolated segments without an intact plantar arch. Limb salvage was achieved and maintained in more than 90% of recent patient cohorts, with a mean procedural mortality rate of 3.3%. Recent strategies that contributed to these results include (1) distal origin short vein grafts from the below-knee popliteal or tibial arteries to an ankle or foot artery (291 cases); (2) combined PTA and bypass (245 cases); (3) more distal PTA of popliteal and tibial artery stenoses (233 cases); (4) use of in situ or ectopic reversed autogenous vein for infrapopliteal bypasses, even when vein diameter was 3 to 4 mm; (5) composite-sequential femoropopliteal-distal (PTFE/vein) bypasses; (6) reintervention when a procedure thrombosed (637 cases) or was threatened by a hemodynamically significant inflow, outflow, or graft lesion (failing graft, 252 cases); (7) frequent follow-up to detect threatening lesions before graft thrombosis occurred and to permit correction of lesions by PTA (58%) or simple reoperation; and (8) unusual approaches to all infrainguinal arteries to facilitate secondary operations, despite scarring and infection. Primary major amputation rates decreased from 41% to 5% and total amputation rates decreased from 49% to 14%. Aggressive policies to save threatened limbs thus are supported.

Transfemoral endoluminal stented graft repair of a popliteal artery aneurysm

This report describes the use of an endoluminally placed stented graft to repair a large (2.6 by 2.6 by 15 cm) popliteal aneurysm in a 63-year-old man with advanced heart disease. Two balloon-expandable stents were attached to a 6 mm polytetrafluoroethylene graft, which was inserted with the patient receiving local anesthetic through a proximal superficial femoral artery arteriotomy. Repeat arteriography and duplex ultrasonography performed up to 3 months after the procedure documented graft and distal artery patency and complete aneurysmal exclusion without distal emboli. This experience demonstrates technical feasibility and early graft patency. However, additional experience and follow-up will be needed to assess the value of this minimally invasive procedure in the management of popliteal aneurysmal disease.

Unsuspected preexisting saphenous vein disease: an unrecognized cause of vein bypass failure

Our prior anecdotal experience with unsuspected preexisting saphenous vein disease prompted us to study its incidence, its relation to graft failure, and to identify techniques for its detection. Thick-walled, postphlebitic sclerotic occluded, postphlebitic sclerotic recanalized, calcified, and varicose vein lesions were detected in 63 (12%) of 513 infrainguinal vein bypasses. In 13 (2% to 5%) cases, severe saphenous vein disease precluded use of the vein. In the remaining 50 cases, the entire vein or a portion thereof, with minimal or unsuspected disease, was used for bypass. Early graft failures occurred in 10 (20%) of the 50 cases. The cumulative primary patency rate at 30 months for bypasses performed with diseased veins was 32%. This was significantly less than the 73% cumulative primary patency rate for bypasses with veins without detectable disease (p less than or equal to 0.001). Retrospective evaluation of preoperative duplex ultrasonography (n = 21) originally used to evaluate saphenous vein length and diameter correctly identified thick-walled, occluded, calcified, and varicose veins in 62% of cases. Intraoperative methods of vein evaluation included inspection, palpation, irrigation, catheter or valvulotome insertion to identify obstruction, and intraoperative arteriography. Histologic examination of diseased veins demonstrated a spectrum of disease with thickening of the intima and media, vein wall calcification, and luminal recanalization. We conclude that (1) unsuspected preexisting saphenous vein disease occurs in approximately 12% of cases and results in both early and late graft failures; (2) detection, in some cases, is possible with duplex ultrasonography and intraoperative techniques; and (3) diseased veins that are recanalized, calcified, or thick-walled should not be used if an alternative vein is available.

Prospective randomized multicenter comparison of in situ and reversed vein infrapopliteal bypasses

We have performed a prospective, randomized, multicenter study to compare in situ and reversed vein grafts for long limb salvage bypasses from the proximal thigh to an infrapopliteal artery. Three hundred eighty-four patients required an infrapopliteal bypass for critical lower extremity ischemia. Of these, 259 were excluded because a short vein bypass was performed or because the vein was considered inadequate. The remaining 125 patients had a randomized vein bypass, 63 reversed, 62 in situ. The two groups were similar with regard to risk factors, indications, graft dimensions, and outflow. Secondary patency at 30 months was similar for both techniques: reversed 67% +/- 9% (+/- SE); in situ 69% +/- 8%. For veins less than or equal to 3.0 mm in minimum distended diameter 24-month patency rates were 61% +/- 22% for 12 in situ veins and 37% +/- 29% for 10 reversed veins (p greater than 0.05). Angiographic evaluation of failing grafts revealed lesions similar in type and frequency in both types of grafts. These included focal (in situ, n = 4; reversed, n = 7) and diffuse vein hyperplasia (in situ, n = 2; reversed, n = 1), and inflow and outflow stenoses (in situ, n = 4; reversed, n = 3). The incidence of wound complications and the mortality rate were similar for the two groups. These data show no significant difference in overall patency rates for the two types of vein grafts at 2 1/2 years.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Short vein grafts: A superior option for arterial reconstructions to poor or compromised outflow tracts?

To determine whether vein graft length is a factor that influences infrapopliteal bypass patency, we reviewed 237 consecutive reversed saphenous vein bypasses performed because of critical ischemia during a 5-year period. One hundred seventeen long vein grafts (LVGs) were longer than 40 cm (42 to 92 cm, mean 60.9 +/- 9 cm) and 120 short vein grafts (SVGs) were 40 cm or shorter (6 to 40 cm, mean 24.7 +/- 8 cm). Ninety-three percent of the LVGs originated from or were proximal to the superficial femoral artery (SFA) whereas all of the SVGs originated at or distal to the SFA. The cumulative patency rate for LVGs at 3 years was 45% and for SVGs was 63% (p less than 0.025). In the absence of an intact pedal arch, 3-year patency rates for LVGs (51 cases) and SVGs (78 cases) were 22% and 53%, respectively (p less than 0.01). High intraoperative outflow resistance measurements (greater than 0.7 mm Hg/ml/min) were encountered in 25 cases. Of these, occlusion within 6 months occurred in six of seven cases with LVGs and in only 8 of 18 cases with SVGs (p less than 0.05). Wound complications at vein harvest sites occurred in 17% of LVGs and in only 6% of SVGs (p less than 0.01). Of 16 additional cases in which a proximal patch angioplasty or percutaneous transluminal angioplasty was performed tandem with a short distal vein graft, four occluded (less than 6 months) and 12 remained patent from 3 to 43 months (mean 12.6 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Polytetrafluoroethylene bypasses to infrapopliteal arteries without cuffs or patches: A better option than amputation in patients without autologous vein

PURPOSE This study was undertaken to evaluate our results of polytetrafluoroethylene (PTFE) tibial and peroneal artery bypasses done for limb salvage. METHODS Within a group of patients undergoing infrainguinal limb salvage bypasses at our institution between January 1986 and May 1995, 63 patients faced an immediate amputation, had no autologous vein on duplex examination and operative exploration, and had only a tibial or peroneal artery as an outflow vessel for bypass. Most of these patients (82%) had two or more prior ipsilateral infrainguinal bypasses. These 63 patients underwent 66 PTFE bypasses to a tibial or peroneal artery without a distal anastomotic vein cuff or an adjunctive arteriovenous fistula. Our results were then compared with those reported from infrapopliteal (crural) bypasses performed with alternate autologous vein sources or PTFE in conjunction with various recommended adjuncts. RESULTS The 3- and 5-year cumulative primary graft patency rates for our PTFE infrapopliteal bypasses were 39%+/-7% and 28%+/-9%, respectively. Secondary graft patency rates were 55%+/-8% and 43%+/-10% at 3 and 5 years, respectively. Limb salvage rates were 71%+/-7% at 3 years and 66%+/-8% at 5 years. Two-year actuarial patient survival rate was only 67%+/-7%. CONCLUSIONS These results indicate that a PTFE bypass to an infrapopliteal artery remains a worthwhile option in patients without usable autologous vein. The secondary patency and limb salvage rates were acceptable in this setting and were not significantly different from the best results reported with prosthetic tibial/peroneal bypasses with distal vein cuffs or patches (74% at 1 year; 58% at 3 years), arteriovenous fistulas (71% at 1 year) or composite arm vein grafts (39% and 29% at 3 and 5 years, respectively).

Human transluminally placed endovascular stented grafts: preliminary histopathologic analysis of healing grafts in aortoiliac and femoral artery occlusive disease.

PURPOSE The purpose of this study was to perform a preliminary histopathologic analysis of explanted human endovascular stented grafts from patients treated for occlusive disease. METHODS Over a 16-month period, 26 endovascular stented grafts were placed in 21 patients with limb-threatening ischemia caused by aortoiliac or femoral artery occlusive disease. All grafts were inserted through open arteriotomies remote from the region of primary disease. During the follow-up period, two patients died of preexisting heart disease 2 weeks and 7 months after grafting, and a portion of their endovascular grafts were the surrounding artery was explanted. Specimens from five other endovascular grafts were obtained during surgical revision for graft stenosis after 3 and 6 weeks and for outflow artery stenosis after 3, 5, and 6 months. All specimens were formalin fixed and studied with hematoxylin and eosin and trichrome staining and immunohistochemically for factor VIII-related antigen, alpha actin smooth muscle, macrophage antigen (MAC-387) and PC-10 (a mouse monoclonal antibody which specifically recognizes proliferating cell nuclear antigen in paraffin sections). RESULTS Three weeks after placement of the stented grafts, organizing thrombus was present on both surfaces of the expanded polytetrafluoroethylene (PTFE) grafts. At 6 weeks, evidence of a neointima with overlying endothelium was seen in the perianastomotic region, and 3 months after grafting it was seen 1 to 3 cm from the anastomosis. The specimen explanted at 5 months demonstrated factor VIII-positive cells 8 cm from the anastomosis. The histopathologic condition of the external capsule appeared to vary, depending on the presence or absence of an external wrap on the PTFE graft and on which layer in the arterial wall the graft was inserted. A foreign body reaction characterized by multinucleated giant cells was seen adjacent to wrapped grafts or around those placed in an intraadventitial plane. Grafts inserted within the media were surrounded by orderly, arranged, smooth muscle cells and few mononuclear cells. Extensive smooth muscle cell proliferation (PC-10 activity) was not seen within native artery atherosclerotic plaques peripherally displaced and external to prosthetic endovascular grafts. CONCLUSIONS These preliminary observations on the healing of PTFE endovascular stented grafts in human beings demonstrate limited plaque hyperplasia and the presence of endothelial cells on the luminal surface remote from the graft-artery anastomosis. It is unclear whether this is a unique manifestation of healing in prosthetic grafts inserted within the walls of arteries.

A twelve-year experience with the popliteal-to-distal artery bypass: the significance and management of proximal disease.

The value of the popliteal-to-distal artery bypass in limb salvage is well documented. However, the influence of progression of disease in the superficial femoral artery or proximal popliteal artery, and the role of percutaneous transluminal angioplasty of these vessels before bypass have not been adequately assessed. To evaluate these and other factors, we reviewed our experience with 153 nonsequential popliteal-to-distal artery bypasses performed over a 12-year period. Limb salvage was the indication for all procedures, and 87% of the patients were diabetic. The 5-year primary and secondary graft patency rates were 55% and 60%, respectively, and the limb salvage rate was 73%. Preoperative arteriograms were evaluated for stenosis in the superficial femoral artery or popliteal artery proximal to the graft. Fifty-six grafts with a proximal stenosis 20% or less were identified and had primary graft patency of 77% at 2 years, similar to the 70% patency for the 20 grafts placed distal to a 21% to 35% stenosis. The 18 grafts placed distal to a stenosis greater than 35% had 53% 2-year primary graft patency (p = 0.25). Percutaneous transluminal angioplasty of a superficial femoral artery or popliteal artery stenosis (24% to 85% luminal narrowing) in 19 limbs resulted in 68% 2-year graft patency, not significantly lower than grafts with 35% or less proximal stenosis (75%, p = 0.25). Other factors associated with significant decreases in graft patency included a vein graft diameter less than 3.0 mm, a dorsalis pedis outflow site, and poor quality outflow. Thus the popliteal-to-distal bypass is a durable procedure.(ABSTRACT TRUNCATED AT 250 WORDS)