Indications and results of arterial stents for occlusive disease

Mid-term outcomes following endovascular re-intervention for iliac artery in-stent restenosis

OBJECTIVES

We sought to evaluate the procedural characteristics and clinical outcomes of endovascular repair for iliac artery (IA) in-stent restenosis (ISR).

BACKGROUND

An increasing percentage of patients with complex IA occlusive disease are treated with an endovascular approach, but the outcomes of IA-ISR have not been well described.

METHODS

We analyzed all endovascular procedures for treatment of IA-ISR performed at our institution between July 2006-December 2010. The primary outcome was primary patency, defined as <50% stenosis as assessed by clinical examination and duplex ultrasonography (DUS).

RESULTS

Forty-one lesions in 24 patients who underwent repeated endovascular intervention for treatment of IA-ISR. Most lesions were unilateral and involved the common IA (66%). The mean length of ISR was 30.1 ± 14.1 mm with type I (focal) and II (diffuse) ISR occurring with the greatest frequency (34% and 39%, respectively). All patients underwent balloon angioplasty; adjunctive stenting zwas performed in 27 (66%) of the lesions. Type II ISR lesions more frequently required stenting (13/16 lesions, P = 0.02 compared with other patterns of ISR). Procedural success was 100% with a mean gain of 0.13 in the ankle-brachial index (P = 0.001). The 6- and 12-month primary patency rates were 96% and 82%, respectively. The 12-month primary-assisted patency rate was 90% with clinically driven target lesion revascularization (TLR) in three patients.

CONCLUSIONS

Endovascular treatment of IA-ISR using an approach of balloon angioplasty followed by selective stenting is associated with high-patency rates and low rates of TLR at 1 year.

Long-term outcomes and predictors of iliac angioplasty with selective stenting

OBJECTIVE

To review our 11-year experience of iliac angioplasty with selective stenting and to evaluate the safety, short- and long-term patency, clinical success rates, and predictive risk factors in patients with iliac artery occlusive disease.

METHODS

From August 1993 to November 2004, 151 iliac lesions (149 stenoses, 2 occlusions) in 104 patients were treated by percutaneous transluminal angioplasty (PTA). The patients had chronic limb ischemia described as disabling claudication (the Society for Vascular Surgery clinical category 2 or 3) in 76 (50%), rest pain (category 4) in 38 (25%), and ulcer/gangrene (category 5) in 37 (25%). Forty-six limbs (30%) were treated with concomitant infrainguinal endovascular (36, 24%) or open procedures (10, 6%). Thirty-four limbs (23%) had one or more stents placed for primary PTA failure, including residual stenosis (> or =30%), mean pressure gradient (> or =5 mm Hg), or dissection (stent group); whereas, 117 limbs (77%) underwent PTA alone (PTA group). The affected arteries treated were 28 (19%) common iliac, 31 (20%) external iliac, and 92 (61%) both arteries. According to TransAtlantic Inter-Society Consensus (TASC) classification, 39 limbs (26%) were in type A, 71 (47%) in type B, 36 (24%) in type C, and 5 (3%) in type D. Reporting standards of the Society for Vascular Surgery and the International Society for Cardiovascular Surgery were followed.

RESULTS

There was no perioperative death. Total complication rate was 0.7% (one groin hematoma). The mean follow-up was 21 months (median, 10; range, 1 to 94 months). Only 9 (8%) of 117 of the PTA group had subsequent stent placement for recurrent stenosis. The iliac lesions were more severe and extensive in the stent group than those in the PTA group according to TASC classification (Mann-Whitney U test [M-W], P < .0001) and anatomic location (M-W, P = .0019). The technical success rate was 99%, and the initial clinical success rate was 99%. Overall, the cumulative primary patency rates at 1, 3, and 5 years were 76%, 59%, and 49% (Kaplan-Meier [K-M]). The cumulative assisted primary and secondary patency rates at 7 years were 98% and 99% (K-M). The mean number of subsequent iliac endovascular procedures was 1.4 per limb in patients with primary failure of iliac angioplasty/stenting. The continued clinical improvement rates at 1, 3, and 5 years were 81%, 67%, and 53% (K-M). The limb salvage rates at 7 year were 93% (K-M). Of 15 predictor variables studied in 151 iliac lesions, the significant independent predictors for adverse outcomes were smoking history (P = .0074), TASC type C/type D lesions (P = .0001), and stenotic ipsilateral superficial femoral artery (P = .0002) for the primary patency rates; chronic renal failure with hemodialysis (P = .014), ulcer/gangrene as an indication for PTA (P < .0001), and stenotic ipsilateral superficial femoral artery (P = .034) for the continued clinical improvement (K-M, log-rank test and Cox regression model).

CONCLUSIONS

Although the primary patency rates were not high, the assisted primary and secondary patency rates were excellent without primary stenting. Overall, >70% of iliac lesions were treated successfully with PTA alone. The results of this study show that selective stenting offers satisfactory assisted primary and secondary long-term patency after iliac angioplasty. Patients with TASC type C/type D iliac lesions, a stenotic ipsilateral superficial femoral artery, ulcer/gangrene, smoking history, and chronic renal failure with hemodialysis should be followed carefully after endovascular iliac revascularization. These risk factors could be considered indications for primary stenting, although further studies are needed to confirm this.

Digital morphometric analysis of the aortic wall in pigs following implantation of dacron-covered stents versus non-covered stents

PURPOSE: To evaluate, by digital morphometry, the intimal thickening after the placement of two different kinds of stents: polyester covered stainless steel stents (Dacron) and non-covered stents implanted in young pigs' infrarenal aortas. METHODS: The experiment was carried out on two separate groups of pigs. Eight polyester-covered stainless steel stents (Dacron) and eight stainless steel stents (30-mm long, 8-mm diameter) were deployed through extraperitoneal approach in the normal infrarenal aorta of 16 normolipemic pigs. To allow the passage of the delivery system, a small arteriotomy was performed (phase I). After four weeks, the aorta with the stent was removed en bloc. (phase II). The values of the hematimetric and lipid analysis did not show any changes that could influence the study. Tissue samples of the fixing sites (proximal and distal) of the stents were taken. Microscope slices were prepared and submitted to Verhoeff's hematoxilin and eosin techniques and sent to morphometric analysis. RESULTS: The intima immediately proximal to the device was thicker in the group of covered stents with marginal significance (p=0.054). The distal intimal layer (p=0.185), proximal medial layer of the proximal portion (p=0.141) and distal portion (p=0.375) did not present statistical difference between the two groups. CONCLUSIONS: Patency was 100% in both groups of these normolipemic pigs. After four weeks the intimal layer immediately proximal to the covered stents was ticker when compared to uncovered stents, but this had a borderline significance. The intimal layer distal to covered stents and the media proximal or distal to the devices had similar morphometric features when covered and uncovered stents where compared.

Surgical management of acute complications and critical restenosis following carotid artery stenting

Carotid artery angioplasty with stenting (CAS) is being increasingly used in the treatment of extracranial carotid artery stenosis. As in other catheter-based approaches to the treatment of arterial disease, surgical intervention may be required because of either acute complications or correct critical restenosis. We have reviewed our experience managing early complications and critical in-stent restenoses after CAS in a tertiary care university hospital and a Veterans Affairs Medical Center. During the last 5 years, 22 carotid arteries (21 patients) underwent CAS. One patient developed thrombosis and rupture of the carotid artery during stenting. Two other patients (3 arteries) developed critical restenosis within 12 months. Subsequent surgical reconstructions included an internal carotid artery (ICA)-to-external carotid artery (ECA) transposition and a common carotid artery (CCA)-to-ICA bypass with reversed saphenous vein (RSV). The patient who underwent CCA-to-ICA bypass later required subclavian-to-ICA bypass because of rapidly progressive intimal hyperplasia and subsequent occlusion of the CCA. The other patient has not had surgical repair because of his deteriorating condition and significant co-morbidities. During the same time period, two additional patients were referred from outside institutions specifically for surgical intervention after carotid stenting. One had delayed rupture of the carotid artery 1 day after stenting and underwent urgent surgical repair. Another patient had early, critical restenosis within the stent and underwent placement of a CCA-to-ICA interposition graft using RSV. Acute treatment failures after CAS can be successfully managed using standard surgical techniques. Patients who develop critical in-stent restenosis requiring surgical repair may need more challenging surgical reconstructions to maintain cerebral perfusion.

Internal to external carotid artery transposition to repair recurrent stenosis after carotid artery stenting

Recently, carotid artery stenting (CAS) has emerged as a treatment option for carotid artery stenosis. Since the procedure is new, management of its complications is not standardized. This case report describes one method of arterial reconstruction after failed CAS. A 64-year-old male underwent CAS of his right internal carotid artery (ICA) for an asymptomatic 65% stenosis. Seven months later the stented area had narrowed to 95%. Arteriography revealed that the common and external carotid arteries (ECA) were free of disease so we elected to perform a transposition of the distal ICA onto the proximal ECA. The ECA and its branches were completely mobilized and the ascending pharyngeal and lingual arteries divided. The ICA was divided distal to the stent. Transection of the occipital artery provided an arteriotomy for an end ICA to side ECA anastamosis, thus preserving ECA flow. Postoperative surveillance after 8 months has revealed no recurrent stenosis. Operative repair of restenosis after CAS may be challenging if standard endarterectomy is not possible. Other options for reconstruction are feasible but if the common and external carotid arteries are disease-free, an ICA to ECA transposition provides a simple all-arterial repair that avoids bypass and prosthetic material.

Carotid stenting for severe radiation-induced extracranial carotid artery occlusive disease

PURPOSE

To present our experience with carotid artery stenting as an alternative treatment to endarterectomy in patients with radiation-induced carotid artery occlusive disease.

METHODS AND RESULTS

Fourteen patients (10 males; mean age 61 years, range 52 to 79) underwent percutaneous stenting of 15 carotid arteries for severe radiation-induced extracranial stenoses. Technical success was achieved in all patients, with reduction of the mean stenosis from 77% +/- 6% to 8% +/- 2%. In 2 patients, ipsilateral vertebral artery lesions were stented concomitantly. One patient had a minor stroke after the procedure but recovered fully in 2 days. No other complications were encountered. Nine (64%) patients had 6-month follow-up imaging (angiography or duplex scanning) that showed no evidence of restenoses (obstruction > or = 50%). At 18 +/- 2 months, 3 (21%) patients had died from unrelated causes. No neurological events occurred, and no repeat carotid artery interventions were required in the remaining patients.

CONCLUSIONS

Carotid stenting is an effective treatment option for severe radiation-induced carotid artery occlusive disease.

Different effects of photodynamic therapy and gamma-irradiation on vascular smooth muscle cells and matrix : implications for inhibiting restenosis

gamma-Irradiation (gamma-RT) and photodynamic therapy (PDT) are known to inhibit intimal hyperplasia. The common mechanism is that both modalities produce free radicals, but unlike gamma-RT, PDT generates them through the absorption of light by photosensitizers. The purpose of this in vitro study was to assess the differences that PDT and gamma-RT have on the fibroproliferative response after vascular injury by comparing their effects on vascular smooth muscle cells (SMCs) and on the extracellular matrix (ECM). Mitochondrial activity (tetrazolium salt), proliferation ([(3)H]thymidine incorporation), and the mechanisms of cell death (terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling [TUNEL] staining) were used to assess differences between PDT (100 J/cm(2)) and gamma-RT (10 or 20 Gy) on SMC injury. The different effects on bioregulatory molecules were investigated by quantitating the proliferation of SMCs cultured with conditioned medium and on treated ECM. PDT of SMCs reduced proliferation and mitochondrial activity (0.5+/-0.75% and 1.7+/-4.25%, respectively, P<0.0001), whereas gamma-RT of SMCs decreased cell proliferation but did not affect metabolic activity. Stimulation with calf serum of gamma-RT-treated SMCs did not affect proliferation but increased mitochondrial enzyme activity (160+/-11%, P<0.0005). The conditioned medium, derived from PDT- but not gamma-RT-treated SMCs, did not stimulate effector SMC proliferation compared with gamma-RT-treated SMCs (16+/-4.1% versus 80+/-16.8%, P<0.0001). Apoptosis was the principle cytotoxic mechanism after PDT, whereas gamma-RT cells were growth arrested but viable. PDT of the ECM reduced effector SMC proliferation compared with controls and gamma-RT cells (18+/-6.5% versus 100+/-17.7% and 84+/-8.9%, respectively, P<0.0001). These data suggest that gamma-RT and PDT may inhibit restenosis but by different mechanisms. The effects of PDT are more diverse and may result in improved outcome while avoiding the teratogenic exposure due to ionizing irradiation.

Aortoiliac stenting, determinants of clinical outcome

OBJECTIVES

To determine predictors of clinical outcome in stenting aortoiliac disease.

DESIGN

Prospective/retrospective study.

MATERIALS AND METHODS

One hundred and forty patients (163 limbs) underwent iliac artery stenting in the period 1994-1997. Ninety-eight occlusions and 65 stenoses were treated, either with primary stenting (n = 129) or after failed angioplasty (n = 34). Median follow-up 18 months (1-66). Factors analysed for their effect on outcome were: gender, age, Fontaine stage, ABI, lesion type/length/site, primary or secondary stenting, stent type, BP, smoking, diabetes, aspirin, cholesterol, residual gradient, overhanging and run-off.

RESULTS

The immediate success was 95%. The primary successful clinical outcome was 90% at 12 months and 84% at 36 months; the primary-assisted successful clinical outcome was 95% at 12 months and 91% at 36 months and the secondary successful clinical outcome was 92% at 12 months and 87% at 36 months. Adverse factors affecting outcome were: residual pressure gradient (> 10 mmHg) and no treatment with aspirin (p < 0.05). Major complications occurred in 18% of patients with a re-intervention in 8%. The 30-day mortality was 5.5%.

CONCLUSIONS

Stenting for aortoiliac occlusive disease has good short and long term clinical success, with low morbidity and mortality. Factors that might improve results further are ensuring that patients are taking aspirin and any residual pressure gradient is abolished.

Balloon angioplasty, stenting, and role of atherectomy

Endovascular interventions for the treatment of lower-extremity atherosclerotic disease have undergone a rapid course of development during the past 30 years. Balloon angioplasty is the most widely applied of these techniques and has been shown to yield excellent results, at least in the short and intermediate terms, in appropriately selected patients. The ideal candidate is one with a focal stenotic lesion of the iliac artery; this is also the type of patient in whom placement of an endoluminal stent, whether primarily or as an adjunct to balloon angioplasty, has been shown to be most effective. The initial enthusiasm for transluminal atherectomy of lower-extremity atherosclerotic lesions has met with some disappointing long-term results. It is now used mainly in conjunction with either or both of the above modalities in a select group of patients. Clearly, more controlled studies of all these techniques are needed to better define their exact indications and limitations in treatment of lower-extremity arterial disease.

Intraoperative endovascular angioplasty and stenting of iliac artery: an adjunct to femoro-popliteal bypass

BACKGROUND

With the rapid development of endovascular techniques, the management strategy of patients with multilevel atherosclerotic arterial occlusive disease is also evolving. Iliac artery stenting is a means whereby multiple bypass operations can be avoided in such patients. The early results of preoperative iliac artery stenting seem promising but the role of intraoperative iliac artery angioplasty and stenting is less clear.

STUDY DESIGN

This study was undertaken to evaluate our early results of a combined endovascular and operative approach to patients with multilevel atherosclerotic arterial occlusive disease. Between June 1995 and March 1997, primary intraoperative iliac artery balloon angioplasty and stent placement were performed on 13 affected limbs of 12 patients undergoing an infrainguinal bypass operation. Indications for operation, patient demographics, and risk factors were noted. The outcome of surgery and the patency rates of bypass graft and stent were also recorded.

RESULTS

The initial technical success of primary iliac artery angioplasty and stenting was 93%. An improvement of the ankle-brachial index by a mean value of 0.38 was attained after operation (p < 0.001). Clinical success, based on the criteria suggested by the Society for Vascular Surgery/International Society for Cardiovascular Surgery, was achieved in all patients. There was no operative or hospital mortality. Postoperative morbidity rate was 8% (n = 1). The cumulative 1-year patency rates of iliac stent and infra-inguinal bypass grafts were 100% and 85%, respectively. The limb loss rate was 7%.

CONCLUSIONS

The technique of intraoperative angioplasty and stenting can be easily mastered by an experienced and skilled vascular surgeon, using a portable C-arm fluoroscopic unit, in the operation theater. A combined endovascular and operative approach optimizes the therapeutic option to this selected group of patients.