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.

Vineberg's procedure modified technique: flow analysis, immediate postoperative results and angiographic evaluation

BACKGROUND

The purpose of this study was to evaluate angiographic results of patients subjected to a technique variation of Vineberg's procedure, as well as their morbidity and mortality in immediate postoperative period, and to analyze the flow of grafted left internal thoracic artery (LITA) at rest and under stress.

METHODS

Between September 1999 and April 2002 eight patients were operated upon, with implant of the internal thoracic artery (ITA) in the intimal layer of the left ventricle (LV) muscle. After 6 months, they underwent angiographic and Doppler evaluation. According to Doppler study of LITA, the sample was divided in two groups: "Vineberg group," formed by eight patients; and "control group" consisting of 20 patients whose LITA directly revascularize the anterior interventricular artery (AIV). Angiography showed patency of all grafts in both groups. Blood flow and flow velocity in grafts were measured by Doppler echocardiography. T-test for paired and unpaired samples were used for statistical analysis.

RESULTS

There were no deaths or complications in immediate postoperative period. Angiography showed 100% patency. The total flow (TF) of Vineberg group was 55% of the flow in the control group. In both groups, the TF increased with the stress.

CONCLUSIONS

This Vineberg's technique modification can be successfully used in patients who cannot undergo traditional direct revascularization due to its low rates of morbidity and mortality and a high rate of patency, providing a significant blood flow both at rest and under stress.

Optimal dosing and duration of oral everolimus to inhibit in-stent neointimal growth in rabbit iliac arteries

BACKGROUND

Everolimus is an orally active derivative of sirolimus. Oral administration of rapamycin is efficacious in the reduction of neointima formation and clinical restenosis; however, its optimal dose and duration have not been determined.

METHODS

New Zealand White rabbits were divided into three groups. The first (low-dose) group received 1.5 mg/kg everolimus 1 day before stenting, followed by 0.75 mg/kg/day everolimus for 28 days. The second (high-dose) group received 6 mg/kg everolimus 1 day before, on the day of, and on the day after stenting, followed by 2 mg/kg/day for 4 days. The third (placebo) group received a matching volume of vehicle similar to that of Group 2. Twenty-eight days after stenting, animals were euthanized and morphometry was performed.

RESULTS

In the high-dose group, circulating everolimus levels corresponded with administrated dose levels; by Day 12, no circulating everolimus could be detected. In the low-dose everolimus group, levels remained constant up to 28 days. When compared with placebo, low-dose everolimus was associated with a significant reduction in medial thickness (32%), neointimal area (60%), and percent stent stenosis (33%); however, high-dose everolimus had no significant effect.

CONCLUSIONS

In conclusion, oral everolimus suppresses in-stent neointimal growth in rabbit iliac arteries. Four weeks of low-dose everolimus is more effective than 7 days of high-dose everolimus.

New concept for CTO recanalization using controlled antegrade and retrograde subintimal tracking: the CART technique

OBJECTIVES

To demonstrate the safety and feasibility of a new concept for CTO recanalization using a controlled antegrade and retrograde subintimal tracking technique (CART technique).

BACKGROUND

A successful percutaneous recanalization of chronic coronary occlusions results in improved survival, as well as enhanced left ventricular function, reduction in angina, and improved exercise tolerance. However, successful recanalization of CTOs is still not optimal, and needs further improvements.

METHODS

Ten patients with a CTO underwent the CART procedure. This technique combines the simultaneous use of the antegrade and retrograde approaches. A subintimal dissection is created antegradely and retrogradely, which allows the operator to limit the extension of the subintimal dissection in the CTO portion. A retrograde approach means that the occlusion site is approached in a retrograde fashion through the best collateral channel from any other patent coronary artery.

RESULTS

The occlusion site was located in the RCA in 9 patients, and in the LAD in 1 patient. CTO duration varied from 7 to 84 months. Vessel recanalization was achieved in all patients. In all cases, the subintimal dissection was limited to the CTO region. No complications occurred in the collateral channel used for the retrograde approach. There were no in-hospital major adverse cardiac events.

CONCLUSIONS

The CART technique is feasible, safe, and has a high success rate.

Lipoplex gene transfer of inducible nitric oxide synthase inhibits the reactive intimal hyperplasia after expanded polytetrafluoroethylene bypass grafting

OBJECTIVE

Intimal hyperplasia (IH) is most commonly the cause of graft occlusion in infrainguinal bypass grafting for arterial occlusive disease. We investigated the influence of nitric oxide on the IH of the arterial vessel wall at the region of prosthetic bypass anastomoses.

METHODS

Experiments were performed in 10 Foxhound dogs. We used a technique of inducible nitric oxide synthase (iNOS) overexpression by a non-virus-mediated, liposome-based iNOS gene transfer. The plasmid pSCMV-iNOS, which drives the expression of iNOS under control of the cytomegalovirus promoter, was complexed with cationic liposomes (lipoplexes). Segments of both carotid arteries were pretreated by intramural injection of a lipoplex solution by using an infiltrator balloon catheter (Infiltrator Drug Delivery Balloon System). In each dog, iNOS was administered at one side, and a control vector (pSCMV2) was administered at the contralateral side. Carotid arteries were ligated, and bypass grafts (expanded polytetrafluoroethylene, 6-mm, ring enforced) were implanted on both sides. The proximal and distal anastomoses (end-to-side fashion; running nonabsorbable sutures) were placed in the pretreated regions. After 6 months, the prostheses were excised, and the intimal thicknesses of 50 cross sections (orcein staining) of each anastomosis were measured planimetrically.

RESULTS

The average reduction of the neointima thickness of the iNOS side in proximal anastomoses at the prosthetic wall, suture region, and arterial wall was 43%, 52%, and 81%, respectively. In distal anastomoses, the average reduction was 40%, 47%, and 52%, respectively. All differences of neointima thickness between the iNOS and control sides were statistically significant (Wilcoxon test; P < or = .05).

CONCLUSIONS

Inducible NOS expression is an efficient approach for inhibition of IH. In contrast to earlier studies, which investigated the efficacy of gene therapeutic NOS expression at 3 to 4 weeks after intervention, the novelty of our findings is that a single local lipoplex-mediated transfection of the vascular wall with iNOS-expressing plasmids leads to a reduction of IH in a prosthetic in vivo model even after 6 months. Because all components can be manufactured under Good Manufacturing Practice conditions (the quality-management system of the European pharmaceutical industry based on ISO 9000), this approach is also amenable to human therapy.

Adjunct brachytherapy: a new concept to prevent intimal hyperplasia after surgical endarterectomy?

OBJECTIVE

Endarterectomy represents a therapeutical option for patients with advanced coronary artery disease. The mid-term results are compromised by restenosis due to neointima formation. The aim of this study was to evaluate a new treatment concept - endarterectomy with consecutive gamma-irradiation - in a rat model.

METHODS

Male Sprague-Dawley rats underwent left carotid endarterectomy with removal of intima: control (n=10) or were irradiated with 15 Gray (Gy) (n=13) or 20 Gy (n=10) postoperatively and compared with sham-operated rats (n=10). After 3 weeks, carotid arteries were perfusion-fixed and vessel compartment areas were measured. Transmission electron microscopy and immunohistochemical staining were used to confirm neointima formation.

RESULTS

Three weeks after endarterectomy, neointimal hyperplasia was found in the control group (0.07+/-0.04 mm(2)). After irradiation, a dose-dependent reduction of neointima was observed (0.003 mm(2) at 15 Gy and 0.0007 mm(2) at 20 Gy, P<0.0001). However, immunohistochemical staining revealed that thin re-endothelialization after irradiation was not inhibited.

CONCLUSIONS

Gamma-irradiation significantly suppressed neointimal hyperplasia in a rat model of surgical endarterectomy. Despite inhibition of intimal hyperplasia, re-endothelialization after adjuvant brachytherapy was present. Adjuvant brachytherapy may be therefore a new concept to prevent restenosis after endarterectomy in patients.

Preinterventional peak monocyte count and in-stent intimal hyperplasia after coronary stent implantation in human coronary arteries

BACKGROUND

The mechanism of restenosis after stent implantation principally is neointimal hyperplasia. There is evidence that monocytes play a important role in in-stent restenosis (ISR) after stent implantation.

HYPOTHESIS

This study assessed the relationship between preinterventional peak monocyte count and neointimal growth after successful stent implantation.

METHODS

We performed coronary stent implantation in 85 patients (85 de novo lesions). Peripheral blood sample was obtained in all patients every 12 h before coronary angiography for measurement of peripheral monocytes. All patients received angiographic and intravascular ultrasound (IVUS) follow-up at 6 months after stenting.

RESULTS

The preinterventional circulating monocyte count was significantly higher in the ISR group than that in the group without ISR (654 +/- 62/vs. 461 +/- 222/mm3, p < 0.001) and was significantly higher in the reintervention group than that in the no-reintervention group (660 +/- 72/ vs. 470 +/- 216/mm3, p< 0.001). The incidence of ISR and repeat intervention associated with preinterventional monocyte count was highest among the patients in the highest tertile, who were at a 2.64-fold increased risk of ISR and 3.22-fold increased risk of repeat intervention compared with the patients in the lowest tertile. A significant positive correlation was found between preinterventional peak monocyte count and preinterventional plaque and media cross-sectional area and follow-up neointima area (r = 0.311, p = 0.007, r = 0.465, p < 0.001, respectively). The neointima area associated with preinterventional monocyte count was largest among the patients in the highest tertile, that is, 2-fold larger than that of the patients in the lowest tertile (p < 0.001) and 1.44-fold larger than that of the patients in the middle tertile (p = 0.001).

CONCLUSION

Our results suggest that circulating preinterventional monocytes play a principal role in the process of in-stent neointimal growth after successful stent implantation.

[Comparative analysis of efficacy of endovascular interventions in native vascular bed and grafts in patients with ischemic heart disease after coronary artery bypass surgery]

AIM

Investigation of efficacy of endovascular interventions in native vascular bed and grafts, elucidation of factors, affecting immediate and remote prognosis after endovascular treatment. MATERIAL AND METHODS Coronary stenting was carried out in 212 patients who had previously undergone coronary bypass surgery. Stents were implanted into native vessels and grafts in 116 (native vessels group) and 96 (grafts group) patients, respectively. Frequency of angina recurrence and development of complications were assessed during hospitalization and after 1 year. Coronary angiography was repeated after 1 year in 47 and 36 patients in native vessels and grafts groups, respectively. Multifactorial analysis of predictors of complications and angina recurrence was performed with the use of logistic regression.

RESULTS AND CONCLUSION

In grafts group signs of distal embolism were observed in 9 patients (9.4%), shunt thrombosis occurred in 2 of these patients. Risk factors of embolism in grafts group were complicated lesions (type C) and length of stenosis >20 mm. There was 1 non-Q wave myocardial infarction after stenting of native vascular bed (0.8%). Angina recurrence was observed after 1 year in 9 (7.8%) and 26 (27.1%), myocardial infarction developed during 1 year in 2 (1.7%) and 3 (3.1%) patients of native vessels and grafts groups, respectively. Risk factors of recurrence of clinic of ischemic heart disease (IHD) after stenting of grafts were time interval between stenting and bypass surgery >5 years and the use of stents without drug coating. More frequent recurrence of clinic of IHD in patients of grafts group was a consequence of higher level of restenosis in stented segments and more frequent progression of atherosclerosis in previously unaffected segments.

[Intimal sarcoma of the inferior vena cava]

INTRODUCTION

Primary sarcomas of the great vessels, that is, the aorta, pulmonary artery, and inferior vena cava, are rare. They can be classified according to the location of the sarcoma in the vessel wall and by their gross appearance. Most often they are leiomyosarcomas or fibrosarcomas.

CASE

We report here a case of an intimal sarcoma of the inferior vena cava. Histological and immunohistochemical findings confirmed the diagnosis for this 17-year-old girl and distinguished it from leiomyosarcoma and angiosarcoma, both of which have better prognoses.

DISCUSSION

Intimal sarcoma of the inferior vena cava is rare and difficult to diagnose before surgery or biopsy. Histologically, it is a poorly differentiated tumor with the worst prognosis among the primary vascular sarcomas. Pathologic findings and immunohistochemical staining are useful for a positive diagnosis.

Impact of asymmetric stent expansion on neointimal hyperplasia following sirolimus-eluting stent implantation

To assess whether asymmetric stent expansion affects suppression of neointimal hyperplasia after sirolimus-eluting stent implantation, 64 patients in the SIRolImUS-coated Bx Velocity stent trial who underwent single 18-mm stent implantation and 3-dimensional intravascular ultrasonography at 8-month follow-up were enrolled. To assess the longitudinal stent asymmetric expansion, 2 cross sections with a maximal/minimal stent area were chosen in each patient. To assess for tomographic stent asymmetric expansion, stent eccentricity was determined by dividing the minimum stent diameter by the maximum stent diameter. At the 2 cross sections with a maximal/minimal stent area, a sirolimus-eluting stent reduced neointimal hyperplasia significantly with no interaction between the treatment and stent areas. A sirolimus-eluting stent also significantly reduced neointimal hyperplasia in the concentric and eccentric stent groups.

Type 1 Collagen as an Endovascular Stent-Graft Material for Small-diameter Vessels: A Biocompatibility Study

PURPOSE

To compare patency rates and degrees of neointimal hyperplasia between bovine type 1 collagen stent-grafts and uncovered control stents in small-diameter vessels (< or =4 mm).

MATERIALS AND METHODS

Uncovered stainless-steel, balloon-expandable stents (n = 5) and type 1 collagen stent-grafts (n = 6) were implanted via the femoral arteries with use of 4-mm balloon catheters into the abdominal aorta of New Zealand White rabbits. Ten animals were available for follow-up. Subjects were followed for 1 month (three uncovered stents; three collagen stent-grafts) or 4 months (two uncovered stents; two collagen stent-grafts). Angiography was performed before animal sacrifice and luminal compromise was compared between groups. Histologic and immunohistochemical analysis was performed to determine presence of neointima and neointimal thickness and area; these parameters were also compared between groups.

RESULTS

All stents and stent-grafts remained patent at both time points. Luminal compromise was not detectable angiographically in any subject. Maximum neointimal thickness was less than 5 mum for all subjects. Neointimal thickness and area were not statistically significantly different between groups.

CONCLUSIONS

Type 1 collagen stent-grafts demonstrate excellent hemocompatibility and biocompatibility in small-diameter vessels in rabbits.

Reduction of Intimal Hyperplasia withRe-188-labeled Stents in a Rabbit Model at 7and 26 Weeks: An Experimental Study

The aim of this study was to analyze the feasibility of (188)Re-labeled stents to reduce neointimal formation in a rabbit atherosclerosis model and to test the long-term effects at 7 and 26 weeks. Fifty-nine male New Zealand White rabbits were fed a 0.5% cholesterol diet for 4 weeks before balloon angioplasty and insertion of Palmaz stents in the infrarenal aorta. The animals were sacrificed 7 and 26 weeks after stent implantation. Control stents were compared with (188)Re stents: (dose 1) 11.3 +/- 1.8 MBq; (dose 2) 37.3 +/- 4.2 MBq, and (dose 3) 80.1 +/- 7.8 MBq. Each activity group consisted of a short-term (7 weeks) and a long-term group (26 weeks), resulting in a total of eight study groups. No thrombotic occlusion was observed. The neointimal formation in the control group was 2.11 [95% confidence interval (CI): 0.68--6.52] mm(2) at 7 weeks and 2.10 (0.62--7.11) at 26 weeks. In the treatment groups, neointima reduction was detectable at 7 weeks [dose 1: 0.33 (0.09--1.22) mm(2); dose 2: 0.17 (0.05--0.57) mm(2); dose 3: 0.03 (0.01--0.13) mm(2)]. After 26 weeks, a catch-up of neointimal formation in the radioactive groups was most obvious in the low-dose group [dose 1: 0.80 (0.28--2.29) mm(2); dose 2: 0.18([0.06--0.52) mm(2); dose 3: 0.50 (0.17--1.42) mm(2)]. Compared to the long-term control group, neointimal reduction was still >60%. No induction of neointimal formation was observed at the edges of the stents. Radiation resulted in delayed re-endothelialization. (188)Re stents were capable to reduce intimal hyperplasia and did not cause thrombosis. The edge effect, which was the major limitation of (32)P stents, was not observed in (188)Re stents.

Two cases of subintimal angioplasty with proximal stent implantation for long superficial femoral artery occlusions

Subintimal angioplasty is a simple and safe alternative to conventional intraluminal angioplasty for the recanalization of diffuse long femoropopliteal occlusions. However, long-term patency rates are unsatisfactory despite the high initial technical success rates. Two cases of occluded left superficial femoral arteries are presented in which subintimal angioplasty with proximal stent implantation was successfully performed. Self-expanding nitinol stents were placed at the proximal part of subintimal plane to maintain good inflow. In both cases, follow-up angiogram at 6 months demonstrated patent stents with good antegrade flow.

Cathepsin G is associated with atheroma formation in human carotid artery

OBJECTIVE

To elucidate the organization of the tissue angiotensin system, we investigated the expression and cellular localization of angiotensin system components and cathepsins D and G, potentially involved in intraparietal angiotensin II formation and atheroma.

METHODS

Total RNA was extracted from atheroma plaque, fatty streaks and macroscopically intact tissue obtained during carotid endarterectomy in 21 hypertensive patients. mRNA levels were compared between these tissues using a semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). In situ hybridization and immunohistochemistry were used to define the cellular localization of the transcripts and their respective proteins.

RESULTS

Apart from renin and angiotensin type 2 (AT2) receptors, which were never detected, the studied mRNAs could be measured in all patients. Angiotensin-converting enzyme (ACE) mRNA was increased five-fold in atheroma, and angiotensin type 1 receptor (AT1) mRNA decreased 2.5-fold in atheroma and 1.4-fold in fatty streaks compared to intact tissue. A two-fold increase in cathepsin G mRNA was observed in atheroma plaque. In atheroma and intact tissue, significant positive correlations were found between cathepsin G and angiotensinogen, AT1 receptor and ACE mRNAs. Angiotensinogen and cathepsin mRNAs and proteins were detected in both arterial layers. AT1 immunoreactivity was mainly associated with alpha-actin-positive cells.

CONCLUSION

All components required for angiotensin II formation are expressed locally in the arterial wall, where, in the absence of renin, cathepsin G could be a major angiotensin-generating enzyme. Overexpression of ACE and cathepsin G may lead to angiotensin II overproduction and contribute, with decreased number of differentiated smooth muscle cells, to the lower amount of AT1 receptor in atheroma.

Incidence and time course of intimal plaque formation in the right coronary artery after radiofrequency current application detected by intracoronary ultrasound

BACKGROUND

Despite the current clinical use of radiofrequency (RF) catheter ablation in infants and children, the late effects of RF current application at immature myocardium remain unclear. The purpose of this study was to investigate incidence and time course of coronary lesions after RF current application at developing myocardium in an animal model.

RESULTS

In 10 pigs, 6 weeks of age (13+/-2 kg), RF current (500 kHz) was delivered by temperature guidance (75 degrees C) using a steerable electrode catheter (4 mm tip electrode) over 30-second periods. RF lesions were created at the lateral right atrial wall at the tricuspid valve annulus and the lateral left atrial and ventricular wall at the mitral valve annulus. Subsequent coronary angiography and intracoronary ultrasound (ICUS) of the right coronary artery (RCA) and the left circumflex artery (CX) were performed 3, 6, 9 and 12 months after RF current application. Quantitative coronary angiography did not exhibit any significant stenosis of the vessels during the study period. Intimal lesions of the RCA were documented for the first time at the 6-month study in 3 animals by ICUS (mean plaque area 2.2+/-0.2 mm(2), mean area stenosis 30.4+/-4.0%). There was no significant change in lesion length, area stenosis and plaque area at the 9- and 12-month studies. All 3 coronary artery lesions were confirmed in close proximity to myocardial RF lesions by histological examination 12 months after RF delivery. No intimal plaque formation of the CX was observed.

CONCLUSIONS

Affection of the RCA as a late sequel after RF current application at the lateral right atrial wall occurred in 3 out of 8 long-term surviving pigs. Three to six months seem to be the time frame for the development of intimal lesions after RF delivery. In this experimental setting, angiography failed to detect these intimal changes. The potential risk of coronary affection may be important for catheter ablation procedures at the right atrial myocardium in infants and small children.

Blockade of Keratinocyte-Derived Chemokine Inhibits Endothelial Recovery and Enhances Plaque Formation After Arterial Injury in ApoE-Deficient Mice

OBJECTIVE

We evaluated the involvement of keratinocyte-derived chemokine (KC) in neointimal hyperplasia and endothelial repair after arterial injury.

METHODS AND RESULTS

Expression of KC was detected by immunohistochemistry in carotid arteries of apolipoprotein E-deficient (apoE-/-) mice not earlier than 2 weeks after wire-injury. Double immunofluorescence staining revealed a colocalization of KC with Mac-2-positive macrophages. Immunoreactivity for KC and its receptor CXCR2 was detectable in regenerating CD31-positive endothelial cells. Treatment of apoE-/- mice with a blocking monoclonal antibody (mAb) to KC after carotid injury for 3 weeks substantially increased neointimal plaque area compared with isotype control-treated or untreated mice. As assessed by luminal CD31 or VE-cadherin and Evans blue staining, neutralization of KC inhibited endothelial recovery in injured arteries, whereas macrophage and smooth muscle cell content were unaffected. In vitro, treatment with KC mAb, a blocking CXCR2 mAb, or the CXCR2 antagonist 8-73GRO-alpha delayed KC-mediated endothelial cell chemotaxis and wound repair of endothelial monolayers after scratch injury. Conversely, addition of exogenous KC accelerated wound repair in a CXCR2-dependent manner.

CONCLUSIONS

Neutralization of KC increased plaque formation and delayed endothelial recovery after arterial injury, without affecting neointimal monocyte infiltration. As an underlying mechanism, KC was involved in promoting CXCR2-mediated endothelial chemotaxis and wound repair.

Neointima formation on vascular elastic laminae and collagen matrices scaffolds implanted in the rat aortae

Synthetic polymers, including polytetrafluoroethylene and Dacron, and biomatrix proteins, including collagen and fibrin, have been used for the construction of vascular substitutes. However, these materials induce inflammatory reactions, contributing to thrombosis, smooth muscle cell (SMC) proliferation, and neointima formation, processes leading to the failure of vascular substitutes. Thus, a pressing issue in vascular reconstruction is to construct vascular substitutes with surface materials that are inflammation-resistant. Here, we demonstrate that the vascular elastic laminae exhibit such a property. Aortic specimens from donor rats were treated with 0.1M NaOH for various times, resulting in elastic lamina-collagen matrix scaffolds with and without the basal lamina. Matrix scaffolds were implanted into the host aorta with three different surface materials, including the elastic lamina, basal lamina, and adventitial collagen, and observed for leukocyte adhesion, endothelial migration, cell proliferation, and neointimal formation on these surfaces. It was found that the elastic lamina was associated with significantly lower leukocyte adhesion, BrdU incorporation, and neointima formation than the basal lamina and adventitial collagen, while the migration of endothelial cells was comparable on all three surfaces. The adventitial collagen matrix was associated with leukocyte infiltration from blood and subsequent SMC migration from the host aorta, whereas the elastic laminae were resistant to such processes. The morphology of the implanted elastic laminae appeared normal at all times. These observations suggest that the vascular elastic laminae exhibit inflammation-resistant properties and inhibit SMC mitogenic activities compared with collagen-containing matrices and may be considered a potential surface material for vascular reconstruction.

Subintimal angioplasty in lower limb ischaemia

Subintimal angioplasty has been suggested as a treatment option for occlusive disease and has become an established practice in some centres, reducing their operative workload considerably. Others have concerns about the safety and durability of the procedure. This review will focus on the evidence for the use of subintimal angioplasty in lower limb occlusive disease. A systematic review of the literature from a Medline search has been carried out. Despite a paucity of trial data, subintimal angioplasty is now an established technique for the treatment of lower limb occlusive disease. The results for femoro-popliteal disease are well documented, with excellent technical and clinical success rates and low complication rates. The results for iliac disease are less well documented and demand caution. For infra-popliteal disease with critical ischaemia, the technique is again safe with good short and long-term results in a group of patients in whom distal bypass surgery is often risky. Subintimal angioplasty has a definite learning curve and those wishing to take it up should visit an experienced centre first. To achieve widespread acceptance it is likely to require large scale randomised controlled trials.

Inhibition of Intimal Hyperplasia by Direct Thrombin Inhibitors in an Animal Vein Bypass Model

Many functions of the coagulation system have nonthrombotic effects. The indirect thrombin inhibitor heparin has been previously shown to be effective in limiting intimal hyperplasia (IH). We sought to study the effect of thrombin on IH by using two direct thrombin inhibitors (DTIs), argatroban and lepirudin. Sprague-Dawley rats underwent interposition vein grafting to the carotid artery. Vein grafts were treated with either saline (n = 6) or one of the two DTIs (n = 6 for both). At 30 days, the rats were sacrificed and vessels were perfusion fixed. Sections of the proximal carotid artery, graft, and both anastomoses were stained with both hematoxlyin/eosin and von Gieson's elastin stain. Sections were examined and compared for luminal area and intima-to-media (IM) ratio. The vessels treated with DTIs had less (p < 0.05) IH (IM ratio for proximal anastomosis: control 1.036 +/- 0.857, lepirudin 0.373 +/- 0.21, argatroban 0.182 +/- 0.118) and better lumen preservation than the control vessels (lumen area of proximal anastomosis: control 1.69 +/- 0.9, lepirudin 2.45 +/- 0.74, argatroban 2.81 +/- 0.78). There were no thromboses in the DTI-treated vessels. Dilatation of the graft segment was noted in the argatroban group. Thus, DTIs are effective at reducing IH in a small-animal model, suggesting that inhibition of thrombin has a protective role in IH. In addition, a difference of action between DTIs is suggested by the dilatation seen only in the argatroban-treated graft sections.

Stapled coronary anastomosis with minimal intraluminal artifact: The S2 Anastomotic System in the off-pump porcine model

OBJECTIVE

A reliable, easy-to-use, 1-shot anastomotic device will significantly push the barrier for less invasive coronary bypass surgery. The current study was designed to test the safety, efficacy, and early patency of a novel distal anastomotic device.

METHODS

The S2 Anastomotic System (iiTech BV, Amsterdam, The Netherlands) was used in 10 consecutive pigs (73 kg) on a mild antiplatelet regimen. In each animal, the device was used to create an internal thoracic artery to left anterior descending bypass on the beating heart. The anastomoses were evaluated intraoperatively (n = 10), at 2 days (n = 2), and at 5 weeks (n = 8) by functional flow measurements, postmortem angiography, and histomorphologic examination.

RESULTS

In all pigs, the S2 Anastomotic System rapidly created successful anastomoses at the first attempt (graft loading and coronary ischemia time: 1.2 +/- 0.3 minutes and 3.0 +/- 0.6 minutes) on target vessels of 1.6 to 2 mm inner diameter. There were no technical failures or anastomotic leaks requiring additional sutures. Both intraoperatively and at the time of death, ischemically induced peak hyperemic flow responses demonstrated widely patent bypasses, which were confirmed by postmortem angiography (FitzGibbon grade A, n = 10) and macroscopic evaluation (anastomotic orifice: 2 mm). Histomorphologic evaluation showed a normal healing response with negligible neointima covering the connector and limited streamlining repair tissue formation between the staple-like elements of the connector.

CONCLUSIONS

The S2 Anastomotic System consistently created automated, fast, and reliable internal thoracic to coronary artery anastomoses on the porcine beating heart with excellent graft patency and healing characteristics at the 5-week follow-up.

[Use of covered stent grafts in treatment of embolism-threatening stenoses and arterial occlusions]

The present work was aimed at demonstrating possibilities and prospects of using covered stent grafts in treatment of patients with embolism-hazardous parietal thrombi, embolism-endangered stenoses, and occlusions of peripheral arteries. Using stent grafts covered with non-woven materials, including PTFE films ("Hemobahn endograft" and "JOSTENT Peripheral Stent Graft") in the arteries of the iliac and femoropoplietal segments, makes it possible to avoid not only acute and delayed occlusions, but to use a PTFE-covered stent graft as a means of isolating the intima from the blood flow, as a method of "inhibiting" intimal hyperplasia in the stented arterial segment. The article deals with clinical follow-ups of patients with embolism-dangerous atherosclerotic stenoses and occlusions of iliac arteries, who underwent successful implantation of covered stents into the affected segments of the arterial bed. These findings demonstrably show high efficacy of using methods of endografting in clinical situations wherein surgical treatment is associated with increased risk.

Post-Dilatation Intravascular Brachytherapy Trials on Hypercholesterolemic Rabbits Using 32P-Phosphate Solutions in Angioplasty Balloons

PURPOSE

Response of peripheral arteries to post-dilatation intravascular brachytherapy (IVBT) using 32P liquid sources was studied in a rabbit model.

METHODS

The applied sources were angioplasty balloons filled with aqueous solutions of Na2H32PO4, NaCl and iodinated contrast. Dose distribution was calibrated by thermoluminescence dosimetry. The uncertainty of in vitro determinations of the activity-dose dependence was +/- 15-30%. The animal experiments were performed on rabbits with induced hypercholesterolemia. The 32P sources were introduced into a randomly chosen (left or right) iliac artery, immediately after balloon injury. Due to the low specific activity of the applied sources, the estimated 7-49 Gy doses on the internal artery surface required 30-100 min irradiations. A symmetric, balloon-occluded but non-irradiated artery of the same animal served as control. Radiation effects were evaluated by comparing the thicknesses of various components of irradiated versus untreated artery walls of each animal.

RESULTS

The treatment was well tolerated by the animals. The effects of various dose ranges could be distinguished although differences in individual biological reactions were large. Only the 49 Gy dose at "zero" distance (16 Gy at 1.0 mm from the balloon surface) reduced hypertrophy in every active layer of the artery wall. The cross-sectional intimal thicknesses after 7, 12, 38 and 49 Gy doses were 0.277, 0.219, 0.357 and 0.196 mm2 respectively, versus 0.114, 0.155, 0.421 and 0.256 mm2 in controls (p < 0.05). The lowest radiation dose on the intima induced the opposite effect. Edge intimal hyperplasia was not avoided, which agrees with other reports. The edge restenosis and the variability of individual response to identical treatment conditions must be considered as limitations of the post-dilatation IVBT method.

CONCLUSION

Only application of highest irradiation doses was effective. The irradiation dose should be planned and calculated for adventitia.

Arterial wall strength after endovascular photodynamic therapy

BACKGROUND AND OBJECTIVES

Vascular photodynamic therapy (PDT) inhibits intimal hyperplasia (IH) induced by angioplasty in rat iliac arteries by eradicating the proliferating smooth muscle cells. This process may jeopardise the structure and strength of the arterial wall, reflected by a decreased bursting pressure.

STUDY DESIGN/MATERIALS AND METHODS

Thirty male Wistar rats of 250-300 g were subdivided into 3 groups (n = 10). In all groups, IH was induced by balloon injury (BI). One experimental group received PDT at 50 J/cm diffuser length, the other group at 100 J/cm diffuser length. The third group served as control group and received no PDT. In half of each group the bursting pressure was analyzed after 2 hours (n = 5), in the other half after 1 year.

RESULTS

Two hours after the procedure the bursting pressure was 3.37 +/- 0.58 (+/-SEM) bar in the BI + PDT 50 and 3.96 +/- 0.43 bar in the BI + PDT 100 group, compared to 2.20 +/- 0.27 bar in the BI group (P < 0.05). After 1 year these values were 3.18 +/- 0.87 bar in the BI + PDT 50 (P < 0.05) and 2.02 +/- 0.31 bar in the BI + PDT 100 group, compared to 2.10 +/- 0.30 bar in the BI group (NS). In the BI + PDT 100 group, 3 out of 5 rats appeared to have aneurysmal dilatation after 1 year.

CONCLUSIONS

Endovascular PDT increases the arterial wall strength as measured by the bursting pressure at short-term. After 1 year, wall strength is not diminished as measured by bursting pressure, but aneurysmal dilatation nevertheless developed with 100 J/cm. dl. This may limit the use of high energy PDT.

Local methylprednisolone delivery using a BiodivYsio phosphorylcholine-coated drug-delivery stent reduces inflammation and neointimal hyperplasia in a porcine coronary stent model

Phosphorylcholine (PC)-coated stents have shown excellent blood and tissue biocompatibility in porcine coronary arteries. The purpose of this study was to determine the efficacy of local methylprednisolone (MP) delivery using PC-coated stents to inhibit inflammatory response and in-stent neointimal hyperplasia in an overstretched porcine coronary model. BiodivYsio (Biocompatibles, Farnham, Surrey, UK) PC-coated drug delivery (DD) stents and DD stents loaded with a high dose of MP (269 microg) were implanted in the coronary arteries of 20 pigs with a balloon/artery ratio of 1.2 : 1. At five days the peri-strut inflammatory response score and thrombus score of the MP-loaded DD stents were lower than in the control stents. The neointimal hyperplasia of MP-loaded DD stents was significantly reduced (0.80 +/- 0.10 versus 0.48 +/- 0.10 mm(2), p < 0.01). At four-week follow-up, the inflammatory response of MP-loaded stents was lower than the control stents, but without significant difference. The MP-loaded stents showed decreased peri-strut arterial injury and in-stent neointimal hyperplasia (2.42 +/- 0.87 versus 1.62 +/- 0.71 mm(2), p < 0.05). It is concluded that local vascular delivery of a high dose of MP from PC-coated DD stents could effectively decrease inflammatory response and thrombus formation after oversized stent deployment and result in a significant reduction of neointimal hyperplasia.

[Subintimal angioplasty. Technique, results and role in the treatment of peripheral arterial occlusive disease]

Subintimal angioplasty consists in entering the subintimal space proximal to the occlusion, traversing the occlusion creating by angioplasty a subintimal channel exiting downstream in the natural lumen. Major complications rarely occur but compromising important collaterals or run-off vessels may be very deleterious. Subintimal angioplasty is indicated in patients with critical limb ischemia, unfit for anesthesia or in the absence of a suitable venous conduit. This technique is mainly effective in long and tibioperoneal occlusions, a location in which transluminal angioplasty usually fails. Further studies are required to determine the modalities of associated anti-thrombotic treatment and if subintimal angioplasty can be used as primary treatment in critical leg ischemia.

Vascular endothelial growth factor (VEGF)-eluting stents: in vivo effects on thrombosis, endothelialization and intimal hyperplasia

Local drug delivery by stent can reduce in-stent restenosis. Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen. After stenting, the arterial wall is almost denuded of endothelium. This loss of endothelium contributes to the smooth muscle cell (SMC) proliferation seen in restenosis, since the endothelium actively inhibits SMC hyperplasia. Over time, the endothelium recovers and SMC hyperplasia is arrested. The capacity of VEGF-coated stents to accelerate re-endothelialization, and to therefore reduce restenosis and thrombosis, was tested in this study. Radiolabeled VEGF was absorbed onto stents and released over nine days in an in vitro perfusion circuit. VEGF-coated stents were deployed in arterial segments to study local tissue release. A New Zealand White rabbit iliac artery model for stent implantation was used. Re-endothelialization and thrombosis were assessed after seven days. Further animals were examined 28 days post-procedure for in-stent restenosis. Stented vessels were resin-embedded, sectioned and stained. Intimal thickening was calculated using computerized morphometry. In vitro, the stents released 80% of the initial load over nine days. At seven days, thrombus was significantly reduced (12.5 mg for controls versus 0 mg for VEGF; p = 0.014). No beneficial effect was seen on endothelialization, nor on intimal hyperplasia. Neointimal area was 2.2 0.9 mm2 for controls versus 2.4 1.8 mm2 for VEGF (p = 0.8). These VEGF-eluting stents do not accelerate re-endothelialization or inhibit restenosis. Stent thrombosis appears to be reduced, which may make these stents less thrombogenic and be valuable in higher-risk cases.

Addition of cytochalasin D to a biocompatible oil stent coating inhibits intimal hyperplasia in a porcine coronary model

BACKGROUND

Polymer-based, drug-eluting stents, are currently under extensive investigation in the conquest against in-stent restenosis. Concern remains, however, about potential long-term lack of biocompatibility of the polymers used in these studies. Therefore, this study aimed to evaluate in porcine coronary arteries (1) the in vivo biocompatibility of a new natural, eicosapentaenoic acid oil stent-coating and (2) the efficacy of this coating in preventing in-stent restenosis when cytochalasin D--an inhibitor of actin filament formation, that interferes with cell proliferation and migration--was added.

METHODS AND RESULTS

To assess in vivo biocompatibility of the oil coating, 15 bare and 15 oil-coated stents were randomly deployed in coronary arteries of 15 pigs. No difference in tissue response, regarding inflammation or proliferation, was seen between both groups at five days or at four weeks follow-up. To evaluate the efficacy of the coating in preventing in-stent restenosis by adding a potential anti-restenotic drug, stents were dip-coated in 20 mg cytochalasin D/ml oil solution, resulting in 93 +/- 18 microg cytochalasin D/stent load (n = 3). In vitro drug release studies showed sustained release up to four weeks. Next, 11 oil-coated and 11 cytochalasin D-loaded stents were randomly implanted in coronary arteries of 11 pigs. At four weeks, a 39% decrease in neointimal hyperplasia (p < 0.05, ANCOVA, with injury as covariate) was found in cytochalasin D-loaded stents compared to oil-coated stents.

CONCLUSIONS

This new natural oil stent-coating shows excellent biocompatibility to vascular tissue. Local cytochalasin D delivery from this stent-platform significantly inhibits neointimal hyperplasia in a porcine coronary model.

Insufficient tissue ablation by rotational atherectomy leads to worse long-term results in comparison with balloon angioplasty alone for the treatment of diffuse in-stent restenosis: insights from the intravascular ultrasound substudy of the ARTIST randomized multicenter trial

The ARTIST trial demonstrated a worse outcome for patients with in-stent restenosis (ISR) treated with rotational atherectomy (RA) and adjunctive balloon angioplasty (PTCA) as compared to PTCA alone. This intravascular ultrasound (IVUS) substudy compares effects of lumen enlargement and examines reasons for failure of RA in this setting. IVUS (n = 56) was performed after each interventional step and at follow-up. Volumetric lumen gain measured 79 +/- 68 mm(3) after PTCA (13 +/- 4 atm) as compared to 44 +/- 26 mm(3) after RA and adjunctive PTCA (7 +/- 3 atm; P < 0.0001). RA itself enlarged lumen by only 19 +/- 17 mm(3) and stent volume was 47% smaller as compared to high-pressure PTCA. Low-pressure strategy after RA did not prevent tissue growth during follow-up (19 +/- 25 vs. 36 +/- 38 mm(3); RA vs. PTCA; P = 0.09). Consequently, net lumen gain after PTCA was 82% higher compared to RA (46 +/- 54 vs. 25 +/- 24 mm(3); P = 0.09). Further stent expansion is the key mechanism to achieve luminal gain by PTCA of ISR. Neointimal ablation by RA has only minor effects. Low-pressure PTCA does not prevent recurrent tissue growth and failed for treatment of ISR due to insufficient stent expansion.

Saratin, an inhibitor of collagen-platelet interaction, decreases venous anastomotic intimal hyperplasia in a canine dialysis access model

Prosthetic dialysis access thrombosis and/or stenosis is the most common cause of graft impairment or loss and is primarily attributed to venous outflow stenosis due to intimal hyperplasia. Intimal hyperplasia is thought to result from interactions between areas of exposed subendothelial collagen in an injured vessel and platelets, resulting in platelet adhesion. Saratin, an inhibitor of the vWF-dependent binding of platelet to collagen interaction, has been shown in vitro to reduce the adhesion of platelets to collagen. In the current study, the authors investigated the effects of topical saratin administration in a canine dialysis access model in regard to intimal hyperplasia development at the venous anastomosis. Fourteen female mongrel dogs underwent placement of a femoral polytetrafluoroethylene (PTFE) dialysis access graft and were placed into 1 of 2 groups: 1) control or 2) experimental with topical saratin application. The experimental group had 600 microg of saratin (1 microg/microL) applied for 5 minutes directly onto the venous anastomosis before restoration of blood flow;control groups received vehicle control. At 4 weeks postoperative, a portion of the graft was removed along with a segment of the outflow vein. Veins were subsequently processed, sectioned, and analyzed along the length of the excised segment and divided into blocks that included the area of the graft toe, midanastomotic region and heel, and blocks A-E. Intimal hyperplasia was assessed by a computer-assisted morphometric analysis. Platelet counts and bleeding times were also measured. Vein segments in the control group (n=7) showed pronounced intimal hyperplasia in blocks B, C, and D as compared to the saratin group (n=6). Distribution of intimal hyperplasia by blocks between control and saratin groups were as follows: block [A] 8.6 +/- 1.9 vs 9.7 +/- 3.0% (p=NS), [B] 32.7 +/- 6.3 vs 10.7 +/- 3.5% (p=0.01), [C] 44.8 +/- 6.2% vs 10.3 +/- 1.5% (p=0.0004), [D] 40.8 +/- 11.0 vs 9.1 +/- 4.2% (p=0.02), [E] 7.5 +/- 5.5 vs 2.7 +/- 0.4% (p=NS). Intimal hyperplasia normalized to vein wall thickness also showed a significant reduction with saratin application. Bleeding times and platelet counts obtained at different time points during the experiment showed no difference between control and saratin groups. In a canine dialysis access model using PTFE grafts, topical application of saratin at the venous anastomosis decreased intimal hyperplasia development by as much as 77% when compared with control animals. Saratin provides for a method of substantially reducing intimal hyperplasia by direct local application without systemic side effects.

Subintimal angioplasty as a treatment of femoropopliteal artery occlusions

OBJECTIVES

to report the results of subintimal PTA of femoropopliteal occlusions above the knee.

DESIGN

a retrospective study.

PATIENTS

in the period from January 1997 to January 2002, 109 patients were submitted to 124 interventions. The indication for treatment was intermittent claudication in 78 cases and critical ischaemia in 46.

METHODS

all cases of subintimal angioplasty were prospectively registered. A review of all cases treated with subintimal PTA for above-knee femoropopliteal occlusions were done. Primary assisted haemodynamic patency rate was calculated on intention to treat basis and for successfully treated cases. Comparison of patency with respect to comorbidities, indication, runoff and occlusion length was done with univariate and multivariate analysis (Cox' regression).

RESULTS

technical success rate was 90%. Primary assisted patency rates at 6, 12 and 18 months were 43, 37 and 31% calculated on basis of intention to treat and 48, 42 and 35% for successfully treated cases. Diabetes mellitus and critical ischaemia were found to be independent risk factors for re-occlusion.

CONCLUSION

subintimal angioplasty is an alternative to open surgery for patients with femoropopliteal occlusions and intermittent claudication. The treatment is relatively atraumatic, complications are rare and in most cases treated with endovascular techniques. Patency rates are low. In cases of critical ischaemia, time can be important for outcome with respect to limb salvage. We therefore find that the poor patency rates of subintimal angioplasty of femoropopliteal occlusions contraindicate its use in the treatment of critical ischaemia with exception of cases unsuitable for surgical treatment.

Vena Cava Filter Behavior and Endovascular Response: An Experimental In Vivo Study

PURPOSE

To evaluate the behavior and endovascular response of a new nitinol permanent vena cava filter, the TrapEase.

METHODS

Percutaneous implantation of the filter was performed in six goats, with inferior vena cava (IVC) diameter close to that of man. Radiologic data concerning the IVC, filter diameter, patency and stability were collected. At 2, 4, 20 and 26 weeks post-implantation, histopathologic analysis of the IVC wall was performed at the site of filter distension, and distal and proximal to the filter.

RESULTS

All filters remained patent. There was no migration and no signs of biological incompatibility. Signs of neointimalization were seen at 2 weeks, with well-developed neointima at 4 weeks. No acute vessel wall perforation was detected by cavography at implantation. During follow-up histologic analysis at 26 weeks, perforation of some of the small fixation barbs was seen, causing minimal damage to the vessel wall and adjacent organ tissue without impairing organ function. These events were well tolerated, probably due to the gradual nature of the penetration of fixation barbs allowing reactive fibrous tissue development. At 26 weeks the parallel filter struts were well covered with neointima and did not perforate the vessel wall. There were no complications associated with the filter implantation.

CONCLUSIONS

The TrapEase vena cava filter was well tolerated and is suitable for incorporation into the IVC wall of healthy animals without any apparent deleterious reaction due to biological incompatibility.

Ascending aorta replacement and local repair of tear site in type A aortic dissection with arch tear

BACKGROUND

Transaortic repair of the tear was previously proposed as a compromise alternative to total arch replacement for acute type A aortic dissection with an arch tear. However, there are no data about long-term prognosis and radiologic findings after this procedure.

METHODS

We reviewed the postoperative course and computed tomographic findings of 13 patients who underwent replacement of the ascending aorta and transaortic repair of an arch tear for acute type A aortic dissection.

RESULTS

There were no early or late deaths during a mean follow-up period of 36.8 months. Computed tomographic follow-up showed complete thrombosis with or without later regression of the false lumen in the descending thoracic aorta in 9 patients (69.2%). Thrombosis of the false lumen usually occurred within 3 months postoperatively. Repair techniques incorporating the full thickness of the aortic wall in closure of the tear resulted in higher rate of success than approximation of the intima only (7 of 8 versus 2 of 5 patients, p < 0.05).

CONCLUSIONS

Transaortic repair of the arch tear with replacement of the ascending aorta can be an option in selected patients who have a small intimal tear in the aortic arch. This option would be more viable for less experienced surgeons who would hesitate to replace the total arch.

Role of side branches in determining suitable arterial segments for anastomosis in avulsion injuries: experimental studies

The role of side branches, when the parent arterial trunk is stretched, with emphasis on preventing the effects of avulsion injury, was investigated in an experimental model. In ten New Zealand rabbits, the femoral arteries were isolated with and without side branches in the left and right legs, respectively, and controlled longitudinal traction was applied. The elongation of the arteries just before avulsion rupture at each side, with and without side branches, was compared, by measuring the initial and final length from the inguinal ligament to the mid-point of the distance between the inguinal ligament and the saphenous bifurcation. Side branches were observed to be tethered in a way that resisted elongation of the trunk artery. Arteries without side branches in the right legs elongated more, as they lacked the fixating and protective support provided by the side branches. Comparison of the two legs, with and without side branches, showed an average of 50 percent more arterial elongation, resulting in severe injury to the arteries without side branches. In the light of these results, the authors suggest performing microsurgical arterial anastomosis after resection past a minimum of two unruptured branch points of the avulsed part, in order to obtain a safer arterial segment for a better patency rate.

Coaxial double-tubular compliant arterial graft prosthesis: time-dependent morphogenesis and compliance changes after implantation

In order to reduce the compliance mismatch between the native artery and the artificial graft, we have developed a coaxial double-tubular compliant graft, using multiply micropored segmented polyurethane (SPU) thin films, which mimics the relationship between the intraluminal pressure and vessel internal diameter (P-D) of the native artery (termed "J" curve). The graft was coaxially assembled by inserting a high-compliance inner tube with a heparin-immobilized photocured gelatin coating layer into a low-compliance outer tube with a photocured hydrophilic polymer coating layer. Twenty-eight coaxial double-tubular compliant grafts were implanted into the canine common carotid arteries in an end-to-end fashion for up to 12 months. The overall patency rate was 86% (24/28), and neither rupture nor aneurysmal formation was observed. A neoarterial wall was formed via transanastomotic and transmural tissue ingrowth, resulting in neoarterial tissue formation on the luminal surface and into the intertubular space of the double-tubular graft, accompanied by mainly myofibroblasts and inflammatory cells in the early stage and endothelialization and collagen-rich extracellular matrices in the late stage of implantation. Surrounding-tissue adhesion with the outer tube was prevented by the hydrophilic polymer coating. Although the J curve of the implanted prototype model was preserved 1 month after implantation, the impaired J curves were observed because of tissue ingrowth and tissue adhesion between the outer surface of the inner tube and the surrounding tissues 3 and 6 months after implantation. At 12 months after implantation, however, the implanted coaxial double-tubular graft exhibited high compliance due to biodegradation of the SPU films.

Ascending aortic dissection without intimal tear: a case report

Aortic dissection may occur without the presence of intimal tear, and it may occur with medial dissection and intramural hematoma. We report a case in which mediastinal enlargement was found in the chest x-ray of a 79-year-old patient with chest and back pain that had started suddenly 1 week before. The patient had a decrease in hematocrit, and transthoracic echocardiography revealed around the heart pericardial fluid 5 cm thick. The ascending aorta could not be evaluated because of the presence of this fluid. The preoperative diagnosis, based on the computerized tomography findings (dissection of ascending aorta and pericardial fluid), was ruptured dissection of the ascending aorta. The patient underwent an emergency operation. Two liters of hemorrhagic fluid was aspirated from the pericardium during the operation. The ascending aorta was opened, but there was no intimal tear. Medial dissection and intramural hemorrhage were seen. The ascending aorta was replaced with a tube graft. Cases such as this, of medial dissection and intramural hematoma in which intimal integrity is preserved, should be approached in the same manner as classical dissections with intimal tear.

Does subintimal angioplasty have a role in the treatment of severe lower extremity ischemia?

OBJECTIVE

Subintimal angioplasty (SIA) has been advocated to treat long segment lower extremity arterial occlusions, but many question its value. We evaluated the role of SIA in a group of patients with severe lower extremity arterial occlusive disease.

METHODS

During a 2.5-year period, 39 patients with arterial occlusions (median length, 8 cm; range, 2 to 31 cm) were treated on an intention-to-treat basis with SIA. Twenty-five patients had gangrene, five had rest pain, and nine had disabling (<one block) claudication. There were 24 superficial femoral, two superficial-femoral-popliteal, four popliteal, two popliteal-tibial, five tibial, and two external iliac artery lesions. With fluoroscopic guidance, via a prograde common femoral artery puncture (n = 29) or a contralateral common femoral artery puncture (n = 9), a subintimal dissection plane was created across the occlusion with a standard guidewire and catheter. The arterial lumen was reentered distal to the occlusion, and the recanalized segment balloon was dilated. All patients were followed prospectively with arterial duplex scan.

RESULTS

SIA was technically successful in 34 of 39 patients (87%). All five failures were from an inability to reenter the patent lumen distally. These five patients underwent successful bypasses that in no case were more distal than would have been required before SIA. In the 34 technically successful SIAs, pain completely resolved (14/14) and areas of gangrene (21/25) healed. The cumulative patency rate in patients who underwent successful SIA was 74% +/- 10% at 12 months. The mean increase in ankle-brachial index after SIA was 0.34 (range, 0.1 to 0.69). There were two distal embolic events, successfully treated surgically (n = 1) or with catheter-directed techniques (n = 1). Three patients underwent subsequent bypass, and the remaining five patients remain asymptomatic.

CONCLUSION

SIA is feasible and can be effective in some patients with lower extremity arterial occlusions and threatened limbs. These results, plus SIA's many advantages, support an increasing role for it in the treatment of lower extremity arterial occlusive disease.

[Relationship between carotid intima-media thickness, atherosclerosis risk factors and angiography findings in patients with coronary artery disease]

The aim was to determine relationship between carotid intima-media thickness and atherosclerosis risk factors and angiographic findings in patients with coronary artery disease.

METHODS

We examined 172 consecutive patients, men and women, aged 58.5 +/- 9.35 years. Eligibility criteria included presence of coronary artery disease that was defined as a history of a heart attack or cardiac catheterization demonstrating > 50% stenosis of at least 1 coronary artery. B-mode ultrasound quantification of carotid artery intima-media thickness was obtained in all patients. Intima-media thickness was measured at left and right carotid arteries and expressed as the mean of the maxima in the common carotid artery, bifurcation and the internal carotid artery. Moreover, the mean of the maxima (IMT) was calculated at all sites. A grade of stenosis was identified and quantified by analyzing Doppler velocity spectrum in combination with measurement of stenosis area in all patients with severe lesions. Obtained results were compared with risk factors of atherosclerosis and angiographic findings on coronary artery angiograms.

RESULTS

There was a statistically significant positive correlation between age (p = 0.0001), hypertension (p = 0.0001), hyperlipidaemia (p = 0.008), non-insulin-dependent-diabetes mellitus (p = 0.043) and intima-media thickness. In 157 (91.3%) patients intima-media thickening and plaques were present in carotid arteries. We observed high-grade stenosis of carotid arteries in 15 patients (8.7%) with coronary artery disease, furthermore all these patients have had at least two-vessel coronary artery disease.

CONCLUSIONS

Alterations within carotid arteries: intia-media thickening and plagues were identified in 91.3% patients. We observed statistically significant correlation between IMT and advancing coronary artery disease. High-grade stenosis of carotid arteries was observed in 8.7% patients with coronary artery disease, furthermore in 13.7% patients with advanced coronary artery disease. IMT increases with age. Hypertension, hyperlipidemia and non-insulin-dependent diabetes mellitus are related to a greater IMT, whereas other risk factors didn't reveal that correlation.

Apoptosis and histopathologic changes in diffuse coronary atherosclerosis

The aims of the study were to investigate the histopathologic characteristics of atherosclerotic lesions and to evaluate the role of apoptosis or programmed cell death in diffuse coronary atherosclerosis. The study included 59 patients who underwent coronary artery bypass grafting coupled with coronary endarterectomy because of diffuse coronary atherosclerosis. Histopathologic analysis of endarterectomy sequesters showed atheroma with confluent extracellular lipid core-type IV lesions in 13 cases (22%); atheroma with lipid core and a cap of fibromuscular layers-type V lesions in 9 cases (15.3%); predominantly calcified fibrous tissue-type VII lesions in 13 cases (22%); and predominantly fibrous tissue-type VIII lesions in 24 cases (40.7%). TUNEL-positive cells were observed in 4 endarterectomy sequesters (6.8%) of subjects with diffuse coronary atherosclerosis. TUNEL-positive cells were demonstrated in the area of mononuclear infiltrates as well as in the vessel wall. The percentage of TUNEL-positive cells in mononuclear infiltrates was 0.5%. Intense mononuclear infiltrates in tunica intima were found in 50% of sequesters, and they consisted of macrophages (40%), T-lymphocytes (17%), and B-lymphocytes (14%). In the area of infiltrates the proportion of MIB-1-positive cells was 2.7%, which was higher than in the intima outside the area of infiltrates (0.5%). In conclusion, apoptosis, which is confined to mononuclear infiltrates, is most likely involved in the development of diffuse coronary atherosclerosis; however, the percentage of apoptotic cells was low (0.5%). A higher proportion of apoptotic cells in the area of infiltrates compared to the rest of the intima was associated with a higher proportion of MIB-1-positive cells. Atherosclerotic lesions in diffuse coronary atherosclerosis were advanced, with a predominance of type VII to VIII lesions.

Efficacy and feasibility of helixcision for debulking neointimal hyperplasia for in-stent restenosis

The Helixcision system is a novel 6 Fr-compatible catheter designed to debulk tissue for in-stent restenosis lesions. The purpose of this study was to determine the efficacy and feasibility of this new system for removing neointimal hyperplasia. A total of 32 in-stent restenosis lesions in 32 patients were treated with helixcision followed by balloon angioplasty. Debulking efficacy was assessed with serial baseline intravascular ultrasound (IVUS) in a subset of 18 lesions. To investigate longitudinal efficacy, 3D analysis was also performed in 12 lesions with automated pullback to calculate average cross-sectional areas across the stent. Prior to procedure, the angiographic reference diameter was 2.60 +/- 0.46 mm. Immediately after procedure, minimum lumen diameter improved from 0.84 +/- 0.33 to 2.19 +/- 0.41 mm (P < 0.0001). IVUS showed a significant reduction of intimal area (IA) after helixcision (from 4.95 +/- 2.04 to 2.88 +/- 1.48 mm(2); P < 0.001). Adjunctive balloon angioplasty further improved lumen area (LA) mainly by stent expansion rather than IA reduction at the site of minimum lumen area. The degrees of IA reduction and LA improvement were closely similar in volumetric analysis. Thirty-day and 6-month clinical follow-up were available in 97% (n = 31) and 72% (n = 23) of the enrolled patients, respectively. At 30-day follow-up, no major adverse cardiac event was reported except for periprocedural CK elevation in two patients (6%). Target legion revascularization within 6 months was performed in six patients (26%). Preliminary results of helixcision indicate that this system is safe and feasible for the treatment of in-stent restenosis. The concordant results between 2D and 3D IVUS analyses suggest that this unique technology can achieve uniform longitudinal debulking throughout the stent. The long-term outcomes appeared to be favorable, considering the relatively diffuse lesion morphology.

The results of subintimal angioplasty in a district general hospital

OBJECTIVES AND DESIGN

we report a prospective study to determine if subintimal angioplasty can be performed in non-teaching centres and to establish its learning curve.

MATERIALS AND METHODS

subintimal angioplasty was performed on 50 limbs in 46 patients (34 male) with a median age of 72 years (range 45-93 years). Indication was critical limb ischaemia (27 limbs) or intermittent claudication (23 limbs). Occlusions were located in the superficial femoral artery in 44 limbs, popliteal artery in 4 limbs and the peroneal artery in two limbs. At a median of 7.9 months patients had colour duplex imaging of the vessels that underwent angioplasty to assess vessel patency.

RESULTS

primary technical success was achieved in 39 cases (78%). Primary technical success was greater in the second group of 25 consecutive limbs to undergo angioplasty at 92% (23 cases) compared with the first 25 consecutive limbs at 64% (16 cases). At 6 months the overall vessel patency rate on duplex imaging was 57%, improving to 64% in the group having a primarily successful procedure. The equivalent rate of symptomatic improvement was 59 and 66% respectively. Complications occurred in five procedures, most were minor, but a single fatality was directly attributable to the procedure.

CONCLUSION

subintimal angioplasty can reasonably be performed outside major teaching institutions. There is a short learning curve associated with the procedure.

Endovascular treatment of experimental wide neck aneurysms: comparison of results using coils or cyanoacrylate with the assistance of an aneurysm neck bridge device

BACKGROUND AND PURPOSE

Endovascular treatment of wide neck aneurysms often results in incomplete occlusion or aneurysm recurrence. The two goals of the present study were to compare results of coil embolization with or without the assistance of an aneurysm neck bridge device (ANBD) and to explore the use of this instrument to control cyanoacrylate embolization.

METHODS

Wide necked bifurcation aneurysms were constructed in 28 dogs. Coil embolization of the aneurysms was performed 2 to 4 weeks later, with (n = 11) or without (n = 10) ANBD assistance. In seven other animals, embolization was performed with cyanoacrylate, injected under the protection of ANBDs. Angiographic results were compared immediately after and at 3 and 12 weeks. Neointima formation at the neck was also compared between groups at 12 weeks.

RESULTS

Initial angiographic results and recurrences at 12 weeks were not significantly different in aneurysms coiled with or without ANBDs. Neointimal scores were also similar. The use of one ANBD at the neck was not sufficient to safely deliver cyanoacrylate into aneurysms. Cyanoacrylate embolization led to improved angiographic results (P =.05) and to better neointimal sealing of the neck of the aneurysms at 12 weeks (P =.004).

CONCLUSION

ANBDs did not prevent recanalization and recurrences after coil embolization of wide neck aneurysms in this animal study. ANBD-assisted cyanoacrylate embolization was unsafe but could decrease recurrences at 12 weeks.

Oxidized LDL in carotid plaques and plasma associates with plaque instability

OBJECTIVE

Oxidation of LDL plays a significant pathogenic role in atherosclerosis. In this study, we attempted to clarify the correlation between the morphology of human atherosclerotic plaques and the oxidized LDL (OxLDL) levels in plasma and carotid plaques.

METHODS AND RESULTS

OxLDL levels (ng/microg apolipoprotein B) in plasma and carotid plaques from 44 patients undergoing carotid endarterectomy and OxLDL levels in 17 control plasma and 9 normal intima samples were determined by a sandwich ELISA by using specific antibodies against OxLDL (DLH3) and apolipoprotein B. The plaques were immunohistochemically classified as macrophage (Mphi)-rich and Mphi-poor. In paired samples from individual patients, plaque OxLDL was nearly 70 times higher than plasma OxLDL (mean+/-SEM, 11.9+/-1.7 vs 0.18+/-0.01 ng/microg apoB, P<0.0001). The OxLDL level was significantly higher in Mphi-rich- than Mphi-poor plaques (19.6+/-2.8 vs 5.50+/-0.77 ng/microg apoB, P<0.0001) and corresponded with DLH3 antigen positivity of the plaques. In patients with Mphi-rich plaques, plasma OxLDL was significantly higher than in the controls (0.20+/-0.02 vs 0.13+/-0.01 ng/microg apoB, P=0.02).

CONCLUSIONS

Our results suggest that LDL undergoes further oxidation in plaques, and that high plasma and plaque levels of OxLDL are correlated with the vulnerability to rupture of atherosclerotic lesions.

Endovascular photodynamic therapy with aminolaevulinic acid prevents balloon induced intimal hyperplasia and constrictive remodelling

BACKGROUND AND OBJECTIVE

intimal hyperplasia (IH) and constrictive remodelling are important causes of restenosis following endovascular interventions, such as percutaneous transluminal angioplasty. Photodynamic therapy (PDT) with 5-aminolaevulinic (ALA) may prevent restenosis by cellular depletion and the elimination of cholinergic innervation.

STUDY DESIGN/MATERIALS AND METHODS

rats (n=90) were subdivided into 4 main groups. In the experimental group (n=36: 3 replications x 4 doses x 3 examination time-points), ALA was administered (200mg/kg i.v.) 2-3h before balloon injury (BI) of the common iliac artery followed by endovascular illumination with 633nm at either 12.5, 25, 50 or 100J/cm diffuser length (dl BI+PDT group). As control groups served the BI+Light only (LO) group (n=36) that received no ALA, the BI only group (n=9) (BI), and a group (n=9) that received a Sham procedure (Sham group).

RESULTS

planimetric analysis showed IH of 0.28+/-0.12mm(2) (BI), 0.27+/-0.12mm(2) (BI+LO at 100J/cmdl) in contrast to 0.02+/-0.02mm(2) after BI+PDT at 100J/cmdl at 16 weeks (p<0.05). In the BI+PDT groups, a light-dose increase of a factor 2 led to an IH decrease of 17% (p<0.05). In the BI and BI+LO groups constrictive remodelling was found, in contrast to BI+PDT treated groups at 16 weeks. The staining of cholinergic innervation of the tunic media of the blood vessel wall in BI+PDT showed no damage at the highest fluence.

CONCLUSION

endovascular ALA-PDT prevents IH and constrictive remodelling after BI without damage of cholinergic innervation of the tunica media. The effective light fluence rate in the rat is 50-100J/cmdl.