External Stents for Vein Grafts in Coronary Artery Bypass Grafting: Targeting Intimal Hyperplasia

INTRODUCTION

Progressive saphenous vein graft (SVG) failure remains a key limitation to the long-term success of coronary artery bypass grafting (CABG). SVG disease after the first year is dominated by intimal hyperplasia, which predisposes the SVG to thrombosis and accelerated atherosclerosis. The objective of this study was to review and summarize the latest experimental and clinical data on the use of mechanical external stents for vein grafts.

METHODS

In January 2020, the PubMed database was searched using the terms "external stent", "CABG", "saphenous vein graft" and "intimal hyperplasia". The results were reviewed and only randomized experimental and clinical studies that analyzed the effect of external stenting on venous intimal hyperplasia were included in the analysis, together with studies that investigated the clinical benefit of external stenting.

RESULTS

Eight experimental and four clinical trials met the search criteria. Controlled trials in different large animal models concluded that external stenting significantly reduced intimal hyperplasia 3-6 months post implantation, and reduced both thrombosis rates and the development of lumen irregularities. Data from randomized controlled trials with a follow-up period of 1-4.5 years supported the pre-clinical findings and demonstrated that external stents significantly reduced vein graft disease.

CONCLUSION

Strong evidence indicates that supporting the vein with external stents is safe and leads to clear advantages at both the anatomical and cellular levels. With the further accumulation of consistent positive results, external stenting of SVG may become the standard of care in future CABG.

The Layer Where the Coronary Arterial "Endarterectomy" Specimen Separates from the Underlying Artery

Described herein is a patient who had a coronary endarterectomy at the time of coronary artery bypass grafting. Histologic study of cross-sections of the endarterectomy specimen disclosed that the layer of separation of the endarterectomy specimen from the underlying native artery was in the media. This layer or plane of excision is virtually always the media irrespective of the artery having the endarterectomy. The procedure might better be called "endomediaectomy?"

Oral Resolvin D1 attenuates early inflammation but not intimal hyperplasia in a rat carotid angioplasty model

Inflammation ensuing from vascular injury promotes intimal hyperplasia (IH) and restenosis. Resolvin D1 (RvD1) is a lipid mediator that attenuates IH in vivo when delivered locally to the vessel wall in animal models. We tested the hypothesis that peri-procedural oral administration of RvD1 could blunt the local inflammatory response to angioplasty, and attenuate downstream IH. Carotid angioplasty was performed on rats fed with either RvD1 or vehicle through oral gavage, starting one day prior to injury until post-operative day (POD) 3 or 14 when arteries were harvested. To study pharmacokinetics and bioactivity of oral RvD1, we measured plasma RvD1 by ELISA, whole blood phagocytosis activity using flow cytometry, and cAMP levels in the thoracic aorta by ELISA. Carotid arteries were harvested on POD3 for staining (anti-CD45, anti-Myeloperoxidase (MPO), anti-Ki67 or dihydroethidium (DHE) for reactive oxygen species), mRNA expression of target genes (quantitative RT-PCR), or on POD14 for morphometry (elastin stain). RvD1 plasma concentration peaked 3 h after gavage in rats, at which point we concurrently observed an increase in circulating monocyte phagocytosis activity and aortic cAMP levels in RvD1-treated rats vs. vehicle. Oral RvD1 attenuated local arterial inflammation after angioplasty by reducing CD45+, MPO+, Ki67+ cells, and DHE staining intensity. Oral RvD1 also reduced the expression of several pro-inflammatory genes within the injured vessels. However, oral RvD1 did not significantly reduce IH. Oral RvD1 attenuated acute inflammation within the arterial wall after angioplasty in rats, but did not significantly affect IH.

Remodeling of a Cell-Free Vascular Graft with Nanolamellar Intima into a Neovessel

Advances in cardiovascular materials have brought us improved artificial vessels with larger diameters for reducing adverse responses that drive acute thrombosis and the associated complications. Nonetheless, the challenge is still considerable when applying these materials in small-diameter blood vessels. Here we report the biomimetic design of an acellular small-diameter vascular graft with specifically lamellar nanotopography on the luminal surface via a modified freeze-cast technique. The experimental findings verify that the well-designed nanolamellar structure is able to inhibit the adherence and activation of platelets, induce oriented growth of endothelial cells, and eventually remodel a neovessel to maintain long-term patency in vivo. Furthermore, the results of numerical simulations in physically mimetic conditions reveal that the regularly lamellar nanopattern can manipulate blood flow to reduce the flow disturbance compared with random topography. Our current work not only creates a freeze-cast small-diameter vascular graft that employs topographic architecture to direct the vascular cell fates for revasculature but also rekindles confidence in biophysical cues for modulating in situ tissue regeneration.

A New Technique to Induce Experimental Myointimal Hyperplasia

BACKGROUND

Arterial myointimal hyperplasia (MIH) has a significant impact on the long-term outcomes of vascular procedures such as bypass surgery and angioplasty. In this study, we describe a new and innovative technique to induce MIH using a dental flossing cachet in Wistar rats.

METHODS

The intimal damage in the common carotid artery was induced by inserting the tip of the dental flossing cachet through the external carotid artery into the common carotid artery and turning it on for 3 rounds of 20 s each (n = 10). After 2 weeks, the rats were anesthetized and the common carotid arteries of the experimental side and the contralateral side (control) were harvested and preserved for histopathological studies.

RESULTS

The experimental carotid arteries showed significant intimal proliferation and thickening compared to the controls. The intima/media ratio of the experimental and normal (control) common carotid arteries were 1.274 ± 0.162 and 0.089 ± 0.023 (mean ± SEM), respectively (p < 0.001).

CONCLUSION

This technique is simple, inexpensive, and highly reproducible and it induces sufficient MIH to study this phenomenon in animal models.

Use of a lyophilized bovine pericardium graft to repair tunical defect in patients with Peyronie's disease: experience in a clinical setting

Many different materials are available for grafting during surgery for Peyronie's disease (PD). To study the outcomes associated with the use of a lyophilized bovine pericardium graft (Peri-Guard®) to repair tunical defects in patients with PD, descriptive study of 43 patients with disabling penile curvature was performed. Curvature was measured before and after the intervention using a standardized procedure. Surgical technique was plaque excision and grafting of the tunical defect carried out by a single surgeon. A lyophilized bovine pericardium patch was used for grafting. We measured the change in penile curvature and length, the ability to perform successful sexual intercourse without further pharmacological or surgical treatment, and the satisfaction with treatment. Follow-up data were available for a total of 41 patients. Median age was 50 years (IQR 48-52); mean follow-up time was 14 ± 6 months. Complete penile straightening was achieved in 33 patients (80.5%) and five patients (12.2%) had curvature under 20°. Three months after surgery and stretching therapy, mean (s.d.) flaccid penile length increased from 11.2 ± 2.8 cm to 12.1 ± 2.9 cm (P = 0.062). Seventy-five percentage of patients reported being able to achieve successful intercourse without further treatment. Eighty-five percentage of patients reported to be satisfied with the treatment. There was no evidence of tissue rejection or infection, and only four patients suffered an adverse event. Plaque excision and grafting of the tunical defect with lyophilized bovine pericardium seems to be a safe and effective treatment for patients with PD.

[Subintimal recanalization. Indications, technique and results]

CLINICAL/METHODICAL ISSUE

This article gives an overview of the current importance of so-called subintimal recanalization in the lower extremities.

STANDARD RADIOLOGICAL METHODS

The primary technical goal of endovascular interventions in the lower extremities is the endoluminal restoration of blood circulation from the iliac arteries into the feet.

METHODICAL INNOVATIONS

If endoluminal recanalization of e.g. high-grade flow-relevant stenoses or chronic total occlusion (CTO) is technically not possible, subintimal recanalization is a promising option and the only remaining minimally invasive alternative. During subintimal recanalization a channel is intentionally generated in the vessel wall (dissection) in order to bypass e. g. a chronic vascular occlusion over as short a distance as possible.

PERFORMANCE

The technical success rate for subintimal recanalization of CTO of the lower extremities is 65-100 %. Technical failure occurs in approximately 25 % using the catheter and wire technique and is caused in most cases by difficulties in reaching the true lumen after the subintimal passage (the so-called re-entry).

ACHIEVEMENTS

Compared to conventional subintimal recanalization, in recent years so-called re-entry devices have expanded the technical possibilities and depending on the medical experience and training level of the physician, provide an improvement in the technical success rate, a lower complication rate, a reduction of fluoroscopy time and the amount of necessary contrast medium but also result in higher costs.

PRACTICAL RECOMMENDATIONS

Subintimal recanalization, whether carried out conventionally with a catheter and wire or using re-entry devices, of high-grade stenoses or CTO in the lower extremities provides a high technical success rate but requires an experienced and trained physician who is capable of operating the elaborate materials and mastering any possible complications.

Subintimal angioplasty for lower limb arterial chronic total occlusions

BACKGROUND

In recent years subintimal angioplasty (SIA) has become an established percutaneous procedure for the treatment of symptomatic lower limb arterial chronic total occlusions. However, the clinical benefits of this practice remain unclear. The aim of the review was to determine the effectiveness of SIA on clinical outcomes. This is an update of a review first published in 2013.

OBJECTIVES

To assess the effectiveness of SIA versus other treatment for people with lower limb arterial chronic total occlusions, determined by the effects on clinical improvement, technical success rate, patency rate, limb salvage rate, and morbidity rates.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register (last searched January 2016) and Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 12). We also searched clinical trials registries.

SELECTION CRITERIA

We included data from randomized controlled trials comparing the effectiveness of SIA and any other management method in the treatment of lower limb arterial chronic total occlusions. The primary intervention of interest was SIA, with or without a stent, for the restoration of vessel patency in people with occlusions of a lower limb artery. We compared SIA against alternative modalities used to restore vessel patency, including conventional percutaneous transluminal angioplasty, surgical bypass, or any other treatments. We compared different SIA devices and techniques against each other.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trials for eligibility and methodological quality, and extracted data. The third review author resolved disagreements.

MAIN RESULTS

Two studies, involving a total of 147 participants with TransAtlantic Inter-Society Consensus (TASC)-II D femoropopliteal lesions, met our inclusion criteria and were included in the review. Both studies were small but otherwise of high methodological quality. However, the treatment techniques and control groups of the two studies differed, precluding the combining of study results and resulting in the evidence being less applicable. We therefore considered the quality of the evidence to be low.In one study, participants with TASC-II D lesions were randomized to receive either SIA with stenting of the superficial femoral artery or remote endarterectomy (RE) with stenting of the superficial femoral artery. Three-year follow-up results showed a Rutherford classification improvement of 64% in the SIA group compared to 80% in the RE group (risk ratio (RR) 0.79, 95% confidence interval (CI) 0.61 to 1.03; 95 participants; P = 0.079). Postexercise ankle brachial index improvements (defined as an increased value of 0.2) were reported in 70% of participants in the SIA group compared to 82% in the RE group (RR 0.86, 95% CI 0.68 to 1.08; 95 participants; P = 0.18). The study reported the technical success rate was 93% for the SIA group and 96% for the RE group (RR 0.97, 95% CI 0.88 to 1.07; 95 participants; P = 0.91). Primary patency at 12 months was 59.1% in the SIA group compared to 78.4% in the RE group (RR 0.75, 95% CI 0.57 to 1.00; 95 participants; P = 0.05). Primary patency at 24 months was 56.8% in the SIA group compared to 76.5% in the RE group (RR 0.74, 95% CI 0.55 to 1.00; 95 participants; P = 0.05) and 47.7% in the SIA group and 62.7% in the RE group at 36 months (RR 0.76, 95% CI 0.52 to 1.11; 95 participants; P = 0.15). Assisted primary patency was 52.3% in the SIA group compared to 70.6% in the RE group (P = 0.01) at 36 months. Secondary patency was better for the RE group (P = 0.03) at 36 months. Limb salvage at three years' follow-up was 95% in the SIA group and 98% in the RE group (RR 0.97, 95% CI 0.90 to 1.05; 95 participants; P = 0.4). There were no perioperative deaths, but complications occurred in two SIA participants (femoral pseudoaneurysm and pulmonary edema) and in three RE participants (seroma, femoral pseudoaneurysm, superficial femoral artery acute occlusion).In the second study, the effects of the SIA OUTBACK re-entry catheter device in people affected by TASC-II D superficial femoral artery chronic total occlusion were compared with the SIA manual re-entry technique. This study did not report clinical improvement and limb salvage. Technical success was achieved in all cases in both the OUTBACK device and manual groups. The primary 6-month patency rate was 100% in the OUTBACK group (26 of 26 participants) compared to 96.2% in the manual group (25 of 26 participants) (RR 1.04, 95% CI 0.94 to 1.15). The primary 12-month patency rate was 92.3% in the OUTBACK group (24 of 26 participants) compared to 84.6% in the manual group (22 of 26 participants) (RR 1.09, 95% CI 0.90 to 1.33). Patency rates at 24 and 36 months were not reported. The study reported that there were no complications.

AUTHORS' CONCLUSIONS

Using the GRADE approach, we classified the quality of the evidence presented by both studies in this review as low due to small study size and the small number of studies. In addition, the two included trials differed from each other in the techniques and control used, and we were therefore unable to combine the data. Consequently there is currently insufficient evidence to support SIA over other techniques. Evidence from more randomized controlled trials is needed to assess the role of SIA in people with chronic lower limb arterial total occlusions.

Histological Analysis of Aneurysm Wall Occluded with Clip Blades. A Case Report

Reports on histological changes of vascular wall following clipping surgery have been scarce. The authors experienced a case of unruptured cerebral aneurysm in which the tissue occluded by clip blades for 6 years was obtained and histologically examined. The aneurysmal wall following clipping showed granulomatous inflammation with necrosis, and occluded aneurysmal walls were found with collagenous fibrous tissue. Mild infiltration by lymphocytes and fibrous thickened intima occurred.

Natural history of minimal aortic injury following blunt thoracic aortic trauma

BACKGROUND

Endovascular repair of blunt traumatic thoracic aortic injuries (BTAI) is common at most trauma centres, with excellent results. However, little is known regarding which injuries do not require intervention. We reviewed the natural history of untreated patients with minimal aortic injury (MAI) at our centre.

METHODS

We conducted a retrospective database review to identify all patients with a BTAI between October 2008 and March 2010. The cohort comprised patients initially untreated because of the lesser degree of injury of an MAI. We reviewed initial and follow-up computed tomography (CT) scans and clinical information.

RESULTS

We identified 69 patients with a BTAI during the study period; 10 were initially untreated and were included in this study. Degree of injury included intimal flaps (n = 7, 70%), pseudoaneurysms with minimal hematoma (n = 2, 20%) and circumferential intimal tear (n = 1, 10%). Six (60%) patients were male, and the median age was 40 years. Duration of clinical follow-up ranged from 1 month to 6 years (median 2 mo) after discharge, whereas CT radiologic follow-up ranged from 1 week to 6 years (median 6 wk). Seven (70%) patients had complete resolution or stabilization of their MAI, 1 (10%) with circumferential intimal tear showed extension of the injury at 8 weeks postinjury and underwent successful repair, and 2 (20%) were lost to follow-up.

CONCLUSION

There appears to be a subset of patients with BTAI who require no surgical intervention. This includes those with limited intimal flaps, which often resolve. Radiologic surveillance is mandatory to ensure MAI resolution and identify any progression that might prompt repair.

[Subintimal angioplasty for chronic arterial occlusive disease: a systematic review]

OBJECTIVE

To evaluate the clinical effectiveness of subintimal angioplasty in treating chronic arterial occlusive disease of lower extremity.

METHODS

Eligible studies concerning treatment by subintimal angioplasty in patients with arterial occlusive disease of lower extremity were identified from electronic database, cross-reference search and relative articles. The study quality and data extraction of all relevant articles were assessed by three independent reviewers. The study endpoints were technical success, primary patency, limb salvage, and complications.

RESULTS

A total of 352 studies were selected for comprehensive review. Fourteen studies including a total of 2350 patients matched the selection criteria. According to whether selective using of re-entry catheter were used or not, the technical success rates were 96.4% and 87% (P < 0.01). Limb salvage rate was 90.5% and 81.5% at 6 and 12 months respectively. Depending on whether preoperative use of anti-platelet drug, primary patency rate was 91% and 68.5% at 6 months respectively (P < 0.01). The complication rate was 8.25% without serious complications.

CONCLUSION

This Meta-analysis suggests that subintimal angioplasty is a safe and effective method in treating chronic arterial occlusive disease of lower extremity with high technical success rate and limb salvage, and low serious complications. Selective using of re-entry devices and preoperative anti-platelet drug can improve the technical success rate and primary patency rate significantly. Despite the high rate of technical and clinical success of the procedure, randomized contrast trials and long-term follow-up results are required to confirm the efficacy of these results.

Tibial microdissection for diabetic wounds

Few data are available focusing on controlled blunt microdissection during below-the-knee interventions as sole or synchronous technique coupled to subintimal angioplasty, particularly in the management of diabetic critical-ischemic foot wounds. We present two cases of targeted recanalizations in the tibial and pedal trunks for plantar and forefoot diabetic ischemic tissue defects, following an angiosome-model for perfusion.

Estrogen replacement attenuates exaggerated neointimal hyperplasia following carotid endarterectomy in rats

BACKGROUND

To investigate whether estrogen may attenuate neointima formation in hyperhomocysteinemic rat carotid endarterectomy.

METHODS

Rats were divided into 6 groups: ovariectomized estradiol-treated homocysteine or chow; ovariectomized placebo-treated homocysteine or chow; intact placebo-treated homocysteine or chow. Chow served as controls while homocysteine served as exaggerated intimal hyperplasia. Prior to endarterectomy, rats were implanted with estradiol mini-pump or placebo, diets given 2 weeks before and after surgery. Homocysteine, estrogen, and neointimal hyperplasia were determined.

RESULTS

Homocysteine was elevated in homocysteine groups versus controls except in estradiol-treated group. Intimal hyperplasia increased in placebo-treated ovariectomized homocysteine versus intact group. Exaggerated intimal hyperplasia in placebo-treated ovariectomized homocysteine was reduced by estrogen and so was homocysteine. Estrogen replacement in ovariectomized homocysteine group reduced intimal hyperplasia to that of intact or ovariectomized controls.

CONCLUSION

Estradiol treatment in this ovariectomized hyperhomocysteinemia carotid endarterectomy and resultant attenuation of homocysteine and neointima may have relevance to the beneficial effects of estrogen on hyperplastic response.

[Collagen fiber pathology in atherosclerotic plaques of the coronary arteries in ischemic heart disease]

Structure-metabolic changes of collagen fibers (CF) in atherosclerosis plaques of the coronary arteries in the conditions of ischemic heart disease (IHD) have been studied. Segments of the coronary arteries were received from 68 men after a coronary artery bypass grafting. CF was study with using of the Van Gieson's and the Masson's methods. Histologic slices were studied by polarization microscopy. The atherosclerosis plaques with IHD were notable for lipidosis of CF. We've suspected lipidosis of CF is a crucial factor for the development of atherosclerosis plaques instability. Evident lipidosis of CF was attended with destructive changes probably resulted in accumulation of atheromatous mass in atherosclerosis plaques.

AIP1 prevents graft arteriosclerosis by inhibiting interferon-γ-dependent smooth muscle cell proliferation and intimal expansion

RATIONALE

ASK1-interacting protein-1 (AIP1), a Ras GTPase-activating protein family member, is highly expressed in endothelial cells and vascular smooth musccells (VSMCs). The role of AIP1 in VSMCs and VSMC proliferative disease is not known.

OBJECTIVE

We used mouse graft arteriosclerosis models characterized by VSMC accumulation and intimal expansion to determine the function of AIP1.

METHODS AND RESULTS

In a single minor histocompatibility antigen (male to female)-dependent aorta transplantation model, AIP1 deletion in the graft augmented neointima formation, an effect reversed in AIP1/interferon-γ receptor (IFN-γR) doubly-deficient aorta donors. In a syngeneic aortic transplantation model in which wild-type or AIP1-knockout mouse aortas were transplanted into IFN-γR-deficient recipients and in which neointima formation was induced by intravenous administration of an adenovirus that encoded a mouse IFN-γ transgene, donor grafts from AIP1-knockout mice enhanced IFN-γ-induced VSMC proliferation and neointima formation. Mechanistically, knockout or knockdown of AIP1 in VSMCs significantly enhanced IFN-γ-induced JAK-STAT signaling and IFN-γ-dependent VSMC migration and proliferation, 2 critical steps in neointima formation. Furthermore, AIP1 specifically bound to JAK2 and inhibited its activity.

CONCLUSIONS

AIP1 functions as a negative regulator in IFN-γ-induced intimal formation, in part by downregulating IFN-γ-JAK2-STAT1/3-dependent migratory and proliferative signaling in VSMCs.

Smooth muscle cells in porcine vein graft intimal hyperplasia are derived from the local vessel wall

BACKGROUND

Accelerated intimal hyperplasia (IH) is an important cause of morbidity and mortality in patients with atherosclerotic vascular disease treated with bypass vein grafts. We used an interposition vein graft model to determine the source of neointimal cells in a clinically relevant large animal model.

METHODS

Jugular vein segments from sex-mismatched, MHC-in-bred pigs were implanted into common carotid arteries bilaterally and harvested up to 8 weeks postsurgery for stereological, histological, and immunofluorescence analyses.

RESULTS

Progressive IH lesions contained macrophages and smooth muscle cells (SMC). Fluorescent in situ hybridization following grafting of female veins into male arteries revealed that only ∼10% of the SMC were male, confirming that the majority of intimal SMC derived from the local vessel wall.

CONCLUSIONS

The majority of neointimal SMC in the IH seen after interposition vein grafting derive from the engrafted local vessel wall. These are the first results from a clinically relevant large animal model that confirm data from rodent models. They have implications for the utility of therapeutic stem cells in this type of intimal hyperplasia.

[Intima-preserving exoprosthetics of ascending aortic aneurism: 15 years of experience]

Short- and long-term follow-up results of intima-preserving exoprosthetics of ascending aortic aneurism in 50 patients were studied. The group of control consisted of 54 patients, whom traditional linear prosthetics of ascending aortic aneurism had been performed. Time of artificial circulation and myocardial ischemia was significantly shorter in first group: 60,3±2,6 min and 21±1,7min, respectively. Patients of both groups showed no significant aortic distension postoperatively (34,5±0,7 - 36,6±0,8 mm). Thus, a dosed resection of the ascending aortic aneurism with intima-preserving exoprosthetics proved to be relatively simple and promising technique.

Comparison of cyanoacrylate-assisted arteriotomy closure with conventional closure technique

BACKGROUND

We aimed to compare conventional suture closure of arteriotomy with N-butyl-cyanoacrylate-assisted suture closure.

METHODS

Forty Wistar rats were randomly divided into two groups. Standard arteriotomy was performed to the abdominal aorta through a midline incision. In the first group, arteriotomy was closed by 3 stitches with 45 degrees between each and in the second by two stitches with 0.1 ml (12-12.5 mg) cyanoacrylate. Amount of blood loss, operation time and severity of myointimal hyperplasia by immunohistochemistry on aorta segments were measured on postoperative days 7 and 30.

RESULTS

Mean anastomotic time was 13.5 +/- 1.64 in the first and 13.0 +/- 1.75 min in the second group (p = 0.356). Operation time was 23.45 +/- 3.63 in the control and 21.0 +/- 3.09 min in the second group (p = 0.027). Mean amount of bleeding was 473.75 +/- 260.5 in the first and 327.5 +/- 155.36 microl in the second group (p = 0.037). Intimal thickness on the 7th day was 80.62 +/- 7.92 in the first and 83.24 +/- 3.42 microm in the second group, and on the 30th day was 81.64 +/- 5.11 in the first and 88.77 +/- 11.03 microm in the second group. The early and late intimal thicknesses were similar (p = 0.35 and 0.87, respectively).

CONCLUSION

Reconstruction of arteriotomies with fewer sutures in combination with cyanoacrylate is a safe method associated with less blood loss and shorter operation time. It also does not lead to increased myointimal hyperplasia.

Neointimal vascularization and intimal thickening in response to self‐expanding stents: a swine model

BACKGROUND

Neovascularization has been suggested as a biological response to vessel injury and associated with restenosis. Self-expanding (SE) stents generate a lasting force on the arterial wall and may lead to an increased arterial response with time.

OBJECTIVES

To characterize the process of neovascularization with SE stents, and to correlate it with vascular injury, inflammation and intimal proliferation.

METHODS

Sixty-nine SE stents were im-planted in 37 non-atherosclerotic pigs.Detailed, multisection histological examination was performed at 15 days, 1, 3 and 6 months post-deployment. Neo-vascularization in addition to other histologic parameters where determined and scored.

RESULTS

Intravascular-ultrasound-based average vessel diameter was 3.3 +/- 0.04 mm; stent size was 3.75 +/- 0.35 mm leading to an oversizing ratio of 1.14 +/- 0.15. Intimal thickness (IT), inflammatory score (IFS) and vascularization score(VAS) reached peak values at three months (IT = 344 +/- 202 1m, IFS = 0.91 +/- 0.5, and VAS = 1.56 +/- 0.8). In contrast,the injury score (INS) continued to increase at all time-points, with maximum value at six months (INS = 1.6 +/- 0.7). Both vascularization and inflammation indices increased with an increase in the injury score (p < 0.01). When vessels were divided according to vascularization score (VAS <1.5 and >1.5) there was a significant difference in IT.

CONCLUSION

Neovascularization in response to SE stents is a time-dependent phenomenon and interacts with injury and inflammation. The remodeling of the vessel wall caused by the sustained force of the SE stent on the arterial wall enhances the formation of neovascularization. Neointimal formation is related to the degree of neovascularization.

Successful recanalization of in-stent coronary chronic total occlusion by subintimal tracking

Percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) caused by in-stent restenosis (ISR) is sometimes very difficult due to the presence of hard occlusive components that prevent wire passage. We report a case of CTO caused by ISR (ISR-CTO) in which the occlusion was crossed with the wire subintimally along the outside of the stent and was successfully re-stented. Subintimal tracking along the outside of the stent can be considered as another approach for PCI of ISR-CTO in cases where conventional approaches fail.

[The clinical values of subintimal angioplasty for treatment lower extremity arterial occlusions]

OBJECTIVE

The purpose of this study was to assess the technical feasibility and early outcomes of subintimal angioplasty to treat lower extremity arterial occlusions.

METHODS

During a 2-year period (from December 2003 to December 2005), 36 lower extremities with arterial occlusions (median length, 11.5 cm; range, 4.5 to 28.0 cm) were treated on an intention-to-treat basis with SIA. Thirteen lower extremities had disabling claudication and twenty-three had limb-threatening ischemia.

MAIN OUTCOME MEASURES

technical success, cumulative patency, clinical results and complications.

RESULTS

The technical success rate was 80% and four out of seven failures were treated by conventional surgery. After 13.2 months follow-up, recanalization vessel patency rate was 70%, and clinical effectiveness rate was 81%, no serious complications occurred.

CONCLUSION

In a selected group of patients, SIA is feasible with a high initial technical success rate and the short-term results are satisfied, SIA is a good treatment alternative in patients who are lower extremity arterial occlusions. The durability of this method of therapy is unknown, and our length of follow-up is not sufficient to answer this question.

[The pilot study of the effect of paclitaxel by local slow delivery on intimal hyperplasia of vascular anastomosis after vascular graft bypass]

OBJECTIVE

To develop a new way to prevent restenosis in the anastomotic site due to intimal hyperplasia after vascular graft bypass (VGB) in peripheral arteries.

METHODS

Five mongrel dogs received bilateral iliac-femoral VGB and their arteries between the graft were ligated and cut off under general anaesthesia. The mixture of the paclitaxel and fibrin gel (FG) were randomly sprayed onto one side of grafts including distal and proximal anastomotic site, and the fibrin gel served as control were sprayed onto the other one. The bilateral grafts including distal and proximal anastomotic site were harvested four weeks postoperationally and the anastomotic sites were observed grossly, pathologically and by electron microscopy. The intimal thickness and area of each anastomotic site were measured, then the data were analysed statistically.

RESULTS

The bilateral grafts of all dogs were patent and the neointima of all anastomotic sites have been seen grossly. The neointimal thickness and area of the experimental side were significantly reduced compared with the control side (P < 0.05). Scanning electron microscopy showed that the anastomotic intima of the experimental side was covered with one layer of intact and regular endothelium cells with deposition of little blood components, but the anastomotic intima of the control side was covered with irregular endothelium cells and deposited with a lot of blood cells and fibrins. Transmission electron microscopy showed the anastomotic intima of the control side that rich in vascular smooth muscle cells and the matrix of the intima was composed of regular collagenous fibers, and that of the experimental side consisted of several types of cells with a lot of foreign particles in the matrix.

CONCLUSION

It is safe and effective to locally use low dose of paclitaxel carried by FG in the prevention of vascular anastomotic site intimal hyperplasia. Paclitaxel molecules can penetrate the graft wall and stay in the anastomotic intima more than four weeks postoperationally.

Removal of Coronary Sinus Intima by a Guidewire during Cardiac Resynchronization Therapy

Previously, complications associated with the placement of the left ventricular pacing lead were reported in 1.9-6% of cases. We describe a case with a stripping of venous intima from the coronary sinus by a guidewire during a left ventricular lead implantation. Judging from this case, the firm guidewire and coronary catheter should not be used within the coronary sinus.

Photodynamic Therapy Reduces Intimal Hyperplasia in Prosthetic Vascular Bypass Grafts in a Pig Model

BACKGROUND

Bypass surgery has a failing frequency of 30% during the first year, mainly due to intimal hyperplasia (IH). This negative effect is most pronounced in artificial grafts. Photodynamic therapy (PDT) is a technique in which light activates photosensitizer dyes to produce free-radicals resulting in an eradication of cells in the vascular wall. The aim of this study was to determine the effectiveness of PDT to reduce IH in a preclinical porcine PTFE bypass model.

MATERIAL AND METHODS

Ten pigs were used. After a pilot PDT dosimetry study (n=3) PTFE grafts were bilaterally placed into the circulation as bypasses from the common to the external iliac arteries (n=7). The right sides served as controls (C). Before implantation of the left grafts, the arterial connecting sites of the left distal anastomoses were PDT-treated. The arteries were pressurized at 180 mmHg for 5 minutes with the photosensitizer Methylene Blue (330 microg/ml), and thereafter endoluminally irradiated with laser light (lambda = 660 nm, 100 mW/cm(2), 150 J/cm(2)). After 4 weeks the specimens were retrieved and formalin fixed. Cross sections through the midportions of the distal anastomoses and the grafts were used for histology, immunohistochemistry to identify inflammatory cells and morphometric evaluation (n=7).

RESULTS

No systemic side effects and no graft occlusions were noted. PDT-treated anastomoses showed reduced IH in the mid-portions of the anastomoses (Area of IH: microm(2)/microm graft: C: 6970+/-1536, PDT: 2734+/-2560; P<0.005) as well as in the grafts (C: 5391+/-4031, PDT: 777+/-1331; P<0.02). The number of inflammatory cells per microscopic field was increased after PDT (C: 24+/-16, PDT: 37+/-15; P<0.009).

CONCLUSIONS

Adjuvant PDT, performed in an endovascular fashion, was a safe method to reduce prosthetic graftstenosis in a preclinical setting. This study underscores the clinical potential of PDT to inhibit the development of clinical bypass graftstenosis.

Direct stenting limits sirolimus-eluting stent edge neointimal thickening

OBJECTIVE

The use of sirolimus eluting stent (SES) has strongly limited the incidence of in-stent restenosis that still remains a problem at the stent edge. The aim of this study was to analyze the neointimal thickening after implantation of SES and to assess the influence of the stent implantation procedure on the neointimal thickening in the in-stent segment and at the edge of the stent in an ex-vivo model of stented human artery.

METHODS

Both balloon expandable SES and the corresponding bare metal stent (BMS) were used in a model of human mammary artery culture. Stents were implanted either directly or after predilatation (10 atm, 60 seconds) and analysis of arterial segments were performed at 28 days poststenting. Cell proliferation and neointimal thickening were assessed by immunohistochemistry, western blotting, and histomorphometry, both in the in-stent segment and at the edge of the stent. Neointimal thickening was expressed as the ratio ([neointimal area/neointimal area + media area]).

RESULTS

The in-stent neointimal thickening was dramatically inhibited in the SES group compared with the BMS group whatever the stenting technique was (predilatation: 0.22 +/- 0.05 vs 0.30 +/- 0.10; P < .04; direct stenting 0.16 +/- 0.04 vs 0.30 +/- 0.13; P <.01). This effect of SES was associated with a smallest expression of the small G protein RhoA and an increase of p27kip expression. In the BMS group, predilatation and direct stenting gave similar in-stent neointimal thickening. In contrast, in the SES group, in-stent neointimal thickening was significantly reduced when direct stenting was performed (0.16 +/- 0.04 [direct stenting] vs 0.22 +/- 0.05 [predilatation], P < .03). At the stent edge, a similar neointimal thickening was observed with both type of stent when predilatation was performed on the entire segment of the artery. Direct stenting significantly reduced the neointimal thickness at the stent edge when SES where used (0.06 +/- 0.01 [direct stenting] vs 0.19 +/- 0.06 [predilatation]; P < .001) but not in the BMS group.

CONCLUSION

These results confirm the efficiency of sirolimus released form SES to inhibit RhoA expression and to increase p27kip level in the arterial wall and show the benefit of direct stenting to limit the edge effect with SES.

Mathematical modeling of 980-nm and 1320-nm endovenous laser treatment

BACKGROUND AND OBJECTIVES

Endovenous laser treatment (ELT) has been proposed as an alternative in the treatment of reflux of the great saphenous vein (GSV) and small saphenous vein (SSV). Numerous studies have since demonstrated that this technique is both safe and efficacious. ELT was presented initially using diode lasers of 810 nm, 940 nm, and 980 nm. Recently, a 1,320-nm Nd:YAG laser was introduced for ELT. This study aims to provide mathematical modeling of ELT in order to compare 980 nm and 1,320 nm laser-induced damage of saphenous veins.

STUDY DESIGN/MATERIALS AND METHODS

The model is based on calculations describing light distribution using the diffusion approximation of the transport theory, the temperature rise using the bioheat equation, and the laser-induced injury using the Arrhenius damage model. The geometry to simulate ELT was based on a 2D model consisting of a cylindrically symmetric blood vessel including a vessel wall and surrounded by an infinite homogenous tissue. The mathematical model was implemented using the Macsyma-Pdease2D software (Macsyma, Inc., Arlington, MA). Calculations were performed so as to determine the damage induced in the intima tunica, the externa tunica and inside the peri-venous tissue for 3 mm and 5 mm vessels (considered after tumescent anesthesia) and different linear endovenous energy densities (LEED) usually reported in the literature.

RESULTS

Calculations were performed for two different vein diameters: 3 mm and 5 mm and with LEED typically reported in the literature. For 980 nm, LEED: 50 to 160 J/cm (CW mode, 2 mm/second pullback speed, power: 10 W to 32 W) and for 1,320 nm, LEED: 50 to 80 J/cm (pulsed mode, pulse duration 1.2 milliseconds, peak power: 135 W, repetition rate 30 Hz to 50 Hz).

DISCUSSION AND CONCLUSION

Numerical simulations are in agreement with LEED reported in clinical studies. Mathematical modeling shows clearly that 1,320 nm, with a better absorption by the vessel wall, requires less energy to achieve wall damage. In the 810-1,320-nm range, blood plays only a minor role. Consequently, the classification of these lasers into hemoglobin-specific laser wavelengths (810, 940, 980 nm) and water-specific laser wavelengths (1,320 nm) is inappropriate. In terms of closure rate, 980 nm and 1,320 nm can lead to similar results and, as reported by the literature, to similar side effects. This model should serve as a useful tool to simulate and better understand the mechanism of action of the ELT.

Development of a reexpandable covered stent for children

The use of covered stents in children is limited by the need for a large long sheath for delivery and the impossibility of redilation once implanted. The authors developed a reexpandable covered stent implantable in children through a small sheath and evaluated its clinical feasibility in mini piglets. An original Palmaz stent was covered with a polyurethane membrane that could be stretched up to 700%. Under general anesthesia, the authors implanted the covered stents in six mini piglets using a long sheath with a diameter approximately 1 French larger than the recommended size required to deliver an uncovered Palmaz stent. The implantation technique was similar to conventional stent implantation. In six piglets, the stent could be redilated from 7.5 to 8.7 mm 28-70 days after implantation. Macroscopic and microscopic examination showed intimal coverage of the coating with minimal inflammatory reaction around the stent. Our newly designed reexpandable stent covered with a polyurethane membrane is promising for use in children.

Sirolimus and paclitaxel provoke different vascular pathological responses after local delivery in a murine model for restenosis on underlying atherosclerotic arteries

BACKGROUND

Drug-eluting stents (DES) have been introduced successfully in clinical practice to prevent post-angioplasty restenosis. Nevertheless, concerns about the safety of DES still exist.

OBJECTIVE

To investigate the vascular pathology and transcriptional responses to sirolimus and paclitaxel in a murine model for restenosis on underlying diseased atherosclerotic arteries.

METHODS

Atherosclerotic lesions were induced by placement of a perivascular cuff around the femoral artery of hypercholesterolaemic ApoE*3-Leiden transgenic mice. Two weeks later these cuffs were replaced either by sirolimus- or paclitaxel-eluting cuffs. The vascular pathological effects were evaluated after two additional weeks.

RESULTS

Both anti-restenotic compounds significantly inhibited restenotic lesion progression on the atherosclerotic plaques. Vascular histopathological analyses showed that local delivery of sirolimus has no significant adverse effects on vascular disease. Conversely, high dosages of paclitaxel significantly increased apoptosis, internal elastic lamina disruption, and decreased medial and intimal smooth muscle cells and collagen content. Moreover, transcriptional analysis by real-time RT-PCR showed an increased level of pro-apoptotic mRNA transcripts (FAS, BAX, caspase 3) in paclitaxel-treated arteries.

CONCLUSIONS

Sirolimus and paclitaxel are effective in preventing restenosis. Sirolimus has no significant effect on arterial disease. In contrast, paclitaxel at high concentration demonstrated adverse vascular pathology and transcriptional responses, suggesting a narrower therapeutic range of this potent drug. Since the use of overlapping stents is becoming more common in DES technology, this factor is important, given that higher dosages of paclitaxel may lead to increased apoptosis in the vessel wall and, consequently, to a more unstable phenotype of the pre-existing atherosclerotic lesion.

Experimental study of a new vascular anastomotic technique in a swine model: short and mid-term results

This study reports the development of a new open external vascular stent: the lock stent device (LSD). It enables a novel end-to-end sleeve anastomotic technique, named locked anastomosis (LA). The LA technique consists of inserting a graft sleeve within an artery, secured in place by an internal stent and an external LSD. The internal stent, graft, vessel wall, and LSD are fastened together with single sutures. The LSD placement does not require a complete transection of the vessel wall as it can be enlarged and then relaxed to clasp the vessel neck. The tensile strength of the LA technique was accurately measured ex vivo and its stability successfully tested in vivo by acute pressure peak tests and mid-term survival studies. Ex vivo, the ratio between the tensile strength of the LA technique with two, three, and six stitches and that of hand-sewn anastomoses was 0.41 +/- 0.02, 0.59 +/- 0.17, and 1.03 +/- 0.04. In vivo, LA anastomoses tolerated marked increases in blood pressure (peak systolic pressure 195-230 mm Hg) for periods of 15-25 min without leakage. Five pigs survived 10 weeks with abdominal aorto-aortic bypass performed according to the LA technique with three stitches. Aortograms showed no narrowing or thromboses, and histological findings confirm uniform flattening of the aortic wall at the anastomosis, with proliferating neointima and uniformly hypotrophic media. Minimal changes were observed in the adventitia.

Traumatic variation of popliteal artery entrapment syndrome

Popliteal artery entrapment syndrome is a well recognised sequelae of anatomical variation in the origin of the medial head of gastrocnemius. It classically presents with distal ischaemia from progressive intimal fibrosis and eventual thrombosis. We present a unique case of acute lower limb ischaemia precipitated by trauma in a young man with undiagnosed popliteal artery entrapment. In this case sudden stress of the lower limb resulted in tearing of the tunica intima of the entrapped artery and exposure of the subendothelium with subsequent thrombus, distal embolisation and acute ischaemia. Successful limb salvage was achieved through endovascular thrombolysis and arterial reconstruction.

Late retrograde aortic perforation by the uncovered part of an endograft: an increasing complication

A 56-year-old man, known for type B aortic dissection, was treated 3 years before with a Talent endograft (Medtronic, Minneapolis, USA) in the descending aorta. He presented with tamponade caused by the perforation of the aortic intima by the uncovered stent strut. The ascending aorta and part of the aortic arch were replaced. The operation and recovery were uneventful. To avoid aortic arch damage by thoracic stent-grafts, the proximal stent should be fully covered. In addition we should be very cautious about the proximal landing zone of the stent, which should not be on the curved portion of the aorta.

The “Safari” Technique to Perform Difficult Subintimal Infragenicular Vessels

The purpose of this study was to describe the efficacy of planned combined subintimal arterial flossing with antegrade-retrograde intervention (SAFARI) to obtain the precise recanalization of the patent portion of a distal runoff vessel in critical limb ischemia (CLI) patients presenting long occlusions involving the popliteal trifurcation. Four patients at risk of limb loss due to long occlusions involving the leg vessel tree and not suitable for a surgical bypass were treated by the subintimal antegrade and retrograde (posterior tibial or anterior tibial artery) approach. The patent portion of the runoff vessel was previously assessed by magnetic resonance angiography (MRA) and directly punctured under Doppler ultrasound (US) guidance. A subintimal channel rendezvous was performed to allow snaring of the guidewires. Subsequently, a balloon dilatation was performed without stent deployment. All patients were successfully recanalized and had complete healing of the limb lesions. At the 12-month follow-up all patients showed clinical improvement with no major complications related to the procedure. This combined antegrade and retrograde subintimal approach is currently an excellent endovascular option in patients with long occlusions extending onto the leg vessels trifurcation and at risk of limb loss.

Subintimal angioplasty

While the technique of subintimal dissection was described almost 2 decades ago, initial adoption of the technique was quite slow. Recently, a growing number of centers have embraced the technique as a valuable adjunct to standard endovascular and open revascularizations. During our experience with over 100 duplex guidance subintimal angioplasties (SIA) and over 100 flouroscopically guided SIA, we have encountered that persistence can be greatest ally. Fortunately, this is a trait that is common among vascular surgeons. Herein, we will describe the technique with focus on its limitations and advantages.

[Effect of RNA interference targeting mammalian target of rapamycin on the proliferation of vascular smooth muscle cell and the intimal hyperplasia]

OBJECTIVE

To construct RNA interference (RNAi) vector of mammalian target of rapamycin (mTOR) and study the effect on the proliferation of vascular smooth muscle cell (VSMC) and the intimal hyperplasia (IH).

METHODS

The sequence of short hairpin RNA (shRNA) targeting mTOR was designed and synthesized by chemical method and inserted into a retroviral vector pLXIN, then the vector was packaged in PT67 cells. The efficiency of inhibition was verified by Northern blot and Western blot after transfection to VSMC. The changes of p70s 6k and 4E-BP1 were also determined. The proliferation activity of VSMC was determined by flowcytometry and MTT. Autogenous vein graft model were established in 54 rats. Three groups were divided, including gene therapy group, control group and vein graft group. The grafted veins were harvested 7 days, 14 days and 28 days after transplanting respectively. The expression of mTOR was determined by immunohistochemistry stain and Western blot. IH was also observed. The apoptotic VSMC was determined by TUNEL.

RESULTS

The shRNA fragments was inserted into pLXIN vector. The shRNA vector was successfully constructed. Additionally, the vector targeting mTOR gene could efficiently decrease the mRNA and protein expression of mTOR and p70s 6k in VSMC, while the expression of 4E-BP1 increased significantly. The cell cycle of VSMC was stunned in phase G(0)/G(1). The protein expression of mTOR in vein graft was inhibited by transfection of pLXIN-shRNA targeting mTOR (P < 0.01) and the IH was also inhibited (P < 0.01), but the apoptosis of VSMC increased significantly (P < 0.01).

CONCLUSION

The mTOR RNAi retroviral vector has been constructed successfully, which can significantly inhibit the proliferation of VSMC and the IH, and promote apoptosis after vein grafting.

[Hyperplasia of the intima as a cause of restenosis following reconstructive and endovascular operations on lower limb arteries]

The authors herein analyse the role of intimal hyperplasia in the development of restenosis as a late complication in reconstructive surgery of arteries in patients suffering from atherosclerosis obliterans of the arteries of the lower extremities.

TIMP-2 Modulates Neointimal Formation in Experimental ePTFE Arterial Grafts

BACKGROUND

In vascular reconstructive surgery, myointimal hyperplasia contributes to the adverse outcome of synthetic grafts. This phenomenon is because of unregulated extracellular matrix degradation and remodeling, and excessive smooth muscle cell proliferation and migration. Matrix metallopreoteinase 2 (MMP-2) is known as an important contributor to these events. The aims of our study was to investigate the effects of selective MMP-2 inhibitor (TIMP-2) in endothelialization rate, SMC proliferation, and myointimal hyperplasia in experimental ePTFE arterial grafts.

METHODS

In 20 male Lewis rats, a 1-cm long ePTFE graft has been inserted at the level of the abdominal aorta. Animals were randomized in two groups (10 animals each): group A received six subcutaneous inoculations of TIMP-2 (2.5 microg) after surgery, group B received only the vehicle of TIMP-2.

RESULTS

Neointimal thickness, as well as SMC density, were augmented in group B, whereas endothelial cells density was augmented in group A, and these findings were statistically significant. In group A SMC were better organized, just like SMC of thoracic aorta. In group B SMC were no organized. Furthermore, anti-TIMP-2 and anti-MMP-2 coloration revealed higher levels of TIMP-2 and lower levels of MMP-2 in group A versus group-B.

CONCLUSIONS

Use of TIMP-2 affects the neointimal formation of experimental e-PTFE arterial grafts, leading to a better-organized neointima, with improved endothelialization.

The Occurrence of Arterio-venous Fistula during Lower Limb Subintimal Angioplasty: Treatment and Outcome

OBJECTIVES

To describe our experience with iatrogenic arterio-venous fistula (AVF) occurring during lower limb subintimal angioplasty, their management and the final clinical, radiological outcome.

DESIGN

Retrospective review of case series from two centres, from a computerised database over a period of five years.

MATERIAL

Twelve patients whose lower limb subintimal angioplasty was complicated by Iatrogenic AVF.

RESULTS

The Majority of AVF occurred at the popliteal trifurcation vessels. And the incidence of this complication in our case series was 0.8%. This was managed with a variety of techniques-Coil embolisation, balloon tamponade, alternative dissection and stent placement. In one patient, the fistula was left open intentionally. All twelve patients had a successful angioplasty. The overall technical success rate for AVF ablation was eighty percent.

CONCLUSIONS

AVF is a potential complication of angioplasty. The majority can be managed by endovascular means during the angioplasty procedure with good technical success.

Duplex-guided endovascular treatment for occlusive and stenotic lesions of the femoral-popliteal arterial segment: A comparative study in the first 253 cases

OBJECTIVE

The standard technique of balloon angioplasty with or without subintimal dissection of infrainguinal arteries requires contrast arteriography and fluoroscopy. We attempted to perform this procedure with duplex guidance to avoid the use of nephrotoxic contrast material and eliminate or minimize radiation exposure.

METHODS

From September 2003 to June 2005, 196 patients (57% male) with a mean age of 73 +/- 10 years (range, 42-97 years) had a total of 253 attempted balloon angioplasties of the superficial femoral and/or popliteal artery under duplex guidance in 218 limbs. Critical ischemia was the indication in 38% of cases, and disabling claudication was the indication in 62%. Hypertension, diabetes, chronic renal insufficiency, smoking, and coronary artery disease were present in 78%, 51%, 41%, 39%, and 37% of patients, respectively. The TransAtlantic Inter-Society Consensus (TASC) classification was used for morphologic description of femoral-popliteal lesions. The common femoral artery was cannulated under direct duplex visualization. Still under duplex guidance, a guidewire was directed into the proximal superficial femoral artery, across the diseased segment(s), and parked at the tibioperoneal trunk. The diseased segment(s) were then balloon-dilated. Balloon diameter and length were chosen according to arterial measurements obtained by duplex scan. Hemodynamically significant defects causing diameter reductions greater than 30% and peak systolic velocity ratios greater than 2 were stented with a variety of self-expandable stents under duplex guidance. Completion duplex examinations and ankle-brachial indices were obtained routinely before hospital discharge.

RESULTS

There were 11 (4%) TASC class A lesions, 31 (12%) TASC class B lesions, 177 (70%) TASC class C lesions, and 34 (14%) TASC class D lesions in this series. The overall technical success was 93% (236/253 cases). Eight of the 17 failed subintimal dissections belonged to TASC class C and the remaining 9 to TASC class D. End-stage renal disease was the only significant predictor of subintimal dissection failure in patients with femoral-popliteal occlusions (5/17 cases; P < .04). Intraluminal stents were placed in 153 (65%) of 236 successful cases. Overall pre-procedure and post-procedure ankle-brachial indices changed from a mean of 0.69 +/- 0.16 (range, 0.2-1.1) to 0.95 +/- 0.14 (range, 0.55-1.3), respectively (P < .0001). The mean duration of follow-up was 10 +/- 7 months (range, 1-29 months). The overall 30-day survival rate was 100%. Overall limb salvage rates were 94% and 90% at 6 and 12 months, respectively. Six-month patency rates for TASC class A, B, C, and D lesions were 89%, 73%, 72%, and 63%, respectively. Twelve-month patency rates for TASC class A, B, C, and D lesions were 89%, 58%, 51%, and 45%, respectively.

CONCLUSIONS

Duplex-guided balloon angioplasty and stent placement seems to be a safe and effective technique for the treatment of infrainguinal arterial occlusive disease. Technical advantages include direct visualization of the puncture site, accurate selection of the proper size balloon and stent, and confirmation of the adequacy of the technique by hemodynamic and imaging parameters. Additional benefits are avoidance of radiation exposure and contrast material.

Subintimal Angioplasty of Tibial Vessel Occlusions in Critical Limb Ischaemia: A Good Opportunity?

OBJECTIVES

To evaluate the feasibility and the mid-term results of subintimal angioplasty (SA) in the treatment of critical limb ischaemia (CLI) with tibial vessels occlusions.

MATERIALS AND METHODS

Between August 2000 and March 2005, we attempted to treat 46 patients (23 men, 23 women, median age of 75 years; range 35-92) and 50 limbs by SA of occluded tibial vessels. Twenty-one had gangrene, 25 ulcerations and 4 had rest pain. Thirty-nine occlusions (78%) were more than 10 cm in length, 28 (56%) involved popliteal and tibial artery and distal re-entry was at the ankle level in 18 cases (36%). Twenty-eight patients (61%) were diabetics.

RESULTS

There were nine technical failures. Five of these patients were successfully treated medically (1), by conventional surgery (1) or by conventional angioplasty of another diseased tibial vessel (3). The four remaining patients had major amputation and 3 died within 3 months. There were 7 complications including 2 embolisms, 1 perforation and 4 haematomas. By intention to treat, one-year primary, secondary and clinical patency rates were 46%, 55% and 63%, respectively. One and two-year limb salvage rates were 87%. One and two-year survival rates were 74% and 64%, respectively.

CONCLUSIONS

SA of tibial vessel occlusions is a valuable treatment of CLI. Technical failures do not preclude conventional surgery when there is a valuable outflow. Complications may often be treated medically or by endovascular procedures. Results have to be confirmed by long-term follow up. Both techniques should be considered as complementary techniques in the management of CLI.

Factors Affecting Patency of Subintimal Infrainguinal Angioplasty in Patients with Critical Lower Limb Ischemia

BACKGROUND

Because subintimal angioplasty (SA) is a technique that can achieve recanalization of long arterial occlusions, it is considered an alternative to lower limb bypass operations. The aim of this prospective study was to identify the risk factors that affect patency of SA in patients suffering from critical limb ischemia (CLI).

METHODS AND RESULTS

51 consecutive infrainguinal SA were done in 46 patients suffered from CLI. The patients were followed-up with regular duplex scans up to 12 months post-intervention. Sex, atherosclerosis risk factors, and some technical details of the procedure (number of patent run-off vessels after the procedure, length and re-entry point of angioplasty) were examined as potential risk factors of patency, using survival analysis statistical techniques. The overall patency rate at 12 months post-intervention was 50%. According to Cox-regression analysis, the factors that affect patency were the number of run-off vessels and the length of occlusion. Patients with two or three run-off vessels had a hazard of occlusion of 0.30 (P = .027) compared to those who had one run-off vessel. The 12-months patency in patients with more than one run-off vessels was 81% vs. 25% in patients with one run-off vessel. Regarding the length of angioplasty, the hazard of reocclusion was 1.02 for every centimeter of occlusion (P = .049).

CONCLUSIONS

The number of patent run-off crural vessels after the angioplasty and the length of occlusion are significant risk factors for reocclusion of infrainguinal SA in patients with CLI. Trying to recanalize more than one run-off vessels could raise the SA patency.

Advances in endovascular treatment of femoropopliteal arterial occlusive disease

Over the past decade, accumulated experience and considerable advances in percutaneous endovascular techniques have enabled their use with increasing frequency for the management of peripheral arterial occlusive disease. However, despite the established role of endoluminal approaches in many other arterial territories, their application for the treatment of femoropopliteal occlusive disease is still debatable due to unique unfavorable anatomical, functional, and flow characteristics of this area. Conventional balloon angioplasty in the femoral and popliteal arteries is frequently associated with suboptimal results and high restenosis rates. To overcome these limitations, emerging approaches have been introduced or are currently under investigation. These include angioplasty modifications, newer concepts in stent design, adjunctive pharmacotherapy, debulking devices, and the application of gamma radiation and freezing in an attempt to reduce intimal hyperplastic response and consequently to expand the application of minimal invasive techniques in the hostile femoropopliteal environment. This review article will present the current status and future trends of endovascular therapy of femoropopliteal artery occlusive disease.

The Potential Role of Optical Coherence Tomography in the Evaluation of Vulnerable Carotid Atheromatous Plaques: A Pilot Study

PURPOSE

The decision to intervene surgically in patients with carotid artery disease is based on the presence of symptoms, along with the severity of carotid artery stenosis as assessed by ultrasound or X-ray computed tomography (CT). Optical coherence tomography (OCT) is a relatively new imaging technique that offers potential in the identification of, as well as the distinction between, stable and unstable atherosclerotic plaques. The purpose of our study was to evaluate whether OCT can be used as a noninvasive diagnostic tool to reveal the morphology of carotid stenosis from the adventitial surface of the carotid artery. To achieve this aim, excised atheromatous plaques were scanned by OCT from the external surface.

METHODS

Plaques removed at carotid endarterectomy were scanned by OCT from the external surface within 72 hr of surgery and then examined histologically. The images of the histologic slides and the scans were then compared.

RESULTS

We examined 10 carotid endarterectomy specimens and were able to identify calcification, cholesterol crystal clefts, and lipid deposits in the OCT images with histologic correlation. The strong light scattering from the calcified tissue and cholesterol crystal clefts limited the depth of light penetration, making observation of the intimal surface and the detail of the fibrous cap difficult. However, we were able to confidently identify the absence of an atherosclerotic plaque by OCT scans even from the external surface.

CONCLUSION

The results of this pilot study demonstrate that OCT can reveal the main features of carotid stenosis but that plaque vulnerability cannot be reliably and precisely assessed if scanned from the external surface with OCT in its present form.

Subintimal angioplasty in the management of lower limb ischaemia

It is now almost 20 years since subintimal angioplasty (SIA) was pioneered. This cost-effective technique has over the past few years enjoyed a dramatic resurgence of interest and application, particularly after having been identified as a safe and practicable approach to vascular recanalisation in several international publications. Originally used in the femoropopliteal segment, its role has been extended to the treatment of infrapopliteal lesions, including the recanalization of the trifurcation and long tibial occlusions. Experienced centres have repeatedly reported primary success rates of around 90% in the infrainguinal vessels, as well as 1-year limb salvage rates as high as 85% to 90%, and 5-year primary assisted patency rates of 64% whilst not interfering with subsequent vascular surgery. Indeed SIA has not only proved to be very effective in lower limb ischaemia management, both for intermittent claudication and critical ischaemia, but in the last few years it has moved from the shadows and into the limelight of modern endovascular therapy.