Endovascular Treatment of Chronic Mesenteric Ischemia: Report of Five Cases

Purpose: To evaluate the midterm results of percutaneous transluminal angioplasty (PTA) and stent placement in stenotic and occluded mesenteric arteries in five consecutive patients with chronic mesenteric ischemia. Methods: Five patients with 70%–100% obliterations of all mesenteric vessels resulting in chronic mesenteric ischemia (n= 4) and as a prophylactic measure prior to abdominal aortic aneurysm repair (n= 1) underwent PTA of celiac and/or superior mesenteric artery (SMA) stenoses (n= 2), primary stenting of ostial celiac occlusions (n= 2), and secondary stenting of a SMA occlusion (n= 1; recoil after initial PTA). All patients underwent duplex ultrasonography (US) (n= 3) and/or angiography (n= 5) during a median follow-up of 21 months (range 8–42 months). Results: Clinical success was obtained in all five patients. Asymptomatic significant late restenoses (n= 3) were successfully treated with repeat PTA (n= 2) and stenting of an SMA occlusion (n= 1; celiac stent restenosis). Recurrent pain in one patient was interpreted as secondary to postsurgical abdominal adhesions. Two puncture-site complications occurred requiring local surgical treatment. Conclusions: Endovascular techniques may be attempted prior to surgery in cases of stenotic or short occlusive lesions in patients with chronic mesenteric ischemia. Surgery may still be preferred in patients with long occlusions and a low operative risk.     

Early detection and treatment of hemodialysis access dysfunction

Purpose: To assess the usefulness of a program for the early detection of hemodialysis graft dysfunction and the impact on graft survival of percutaneous transluminal angioplasty (PTA) and stent implantation to correct venous stenosis. Methods: A program for the early detection of hemodialysis access graft dysfunction was carried out in 110 patients over a period of 80 months. Detection was based on physical examination, flow rate measurements, venous pressure, and analytical determinations performed at dialysis. The stenoses detected were treated by PTA or PTA plus stent deployment. Survival curves compared primary and assisted patency rates for the different graft types. Results: The most important indicators of dysfunction were increased venous pressure and difficulty in cannulation of the graft. Significant stenoses were revealed by 227 (92.2%) of the 246 fistulography procedures performed. PTA results were satisfactory in 100% of the Thomas grafts, 74% of the Brescia-Cimino (BC) grafts, and 53% of the polytetrafluoroethylene (PTFE) grafts. Technical success rates for stent deployment were 92% for BC grafts and 100% for PTFE grafts, while functional success rates were 96% and 97%, respectively. The difference in the primary patency (P1) and assisted patency (AP) values was statistically significant for all three graft types. There was no significant difference in the patency rates for grafts treated by PTA alone or by PTA and stent deployment. Conclusion: A surveillance program helped prevent graft thrombosis, and intervention as required achieved excellent primary and assisted patency rates. Stent deployment salvaged a considerable number of accesses but did not significantly extend access survival time.     

Endovascular stenting for unsuccessful angioplasty of the aorta in aortoarteritis

Purpose: The efficacy and safety of endovascular stent implantation to correct dissection or a suboptimal result after percutaneous transluminal angioplasty (PTA) was evaluated in patients suffering from aortic stenosis due to aortoarteritis. Methods: Twelve children and young adults [aged (mean ± SD) 18.2 ± 8.7 years] underwent stent implantation after PTA of the aorta, seven for obstructive dissection, four for ineffective balloon dilatation, and one for recurrent restenosis. Nine patients underwent implantation of self-expandable stents and three received balloon-expandable Palmaz stents. Results: Stent implantation could be successfully performed in all 12 patients. After stent implantation, the peak systolic pressure gradient decreased from 91 ± 33.5 mmHg to 12.4 ± 12.5 mmHg (p < 0.001). The diameter of the stenosed segment increased from 4.6 ± 0.8 mm to 11.1 ± 1.9 mm (p < 0.001). The dissection was completely covered in all seven patients with dissection. Except for epigastric pain with vomiting in one patient, there was no complication. On follow-up, over 12–57 months (mean 26.8 ± 10.8 months), 11 patients (91.6%) had marked improvement in their blood pressure. Patients with congestive heart failure and claudication also showed improvement. Repeat catheterization in five patients, between 6–30 months (mean 16.8 ± 9.1 months) after stent implantation, showed sustained improvement in four and a fusiform, long segment, intrastent restenosis after 30 months in one child. The stenosis was safely redilated. Conclusion: Endovascular aortic stent implantation is safe and provides good immediate relief in patients with unsatisfactory results after balloon angioplasty. Improvement is sustained in most patients on intermediate-term follow-up.     

Popliteal Artery Stenting Using Flexible Tantalum Stents

Purpose: To evaluate the safety and efficacy of stent therapy for the treatment of residual stenoses after percutaneous transluminal angioplasty (PTA) of popliteal stenoses and occlusions. Methods: In a prospective single-center study, flexible tantalum stents were implanted in 32 popliteal arteries for the treatment of residual stenosis greater than 50% after PTA of stenoses (n = 17) or occlusions (n = 15) in the P1 (n = 16), the P2 (n = 13), or both P1 and P2 segment (n = 3). Follow-up patency was assessed by clinical examination, ankle-brachial index, and color Doppler sonography or angiography. Results: Early stent thrombosis (10 days): 1 of 32 arteries (3%). 1-year and 2-year primary patency rate (PPR): 81% ± 7.1% and 74% ± 9.1%, respectively. 1-year PPRs for subgroups: stented stenoses versus stented occlusions: 88% ± 7.8% vs 73% ± 12.0%, p = 0.12; good lower limb runoff versus poor: 84.0% ± 8.7% vs 76.0% ± 12.4; p = 0.09; P1 versus P2: 77.3% ± 9.8% vs 85.7% ± 9.4%, p = 0.38. Recurrent PTA lesions treated with stents showed higher restenosis rate than de novo lesions. Conclusion: The results of stent therapy of residual popliteal stenosis after PTA are encouraging and warrant further investigation.     

Management of failing prosthetic bypass grafts with metallic stent placement

Purpose: To evaluate the role of metallic stents in treating stenoses involving prosthetic arterial bypass grafts. Methods: Patients undergoing stent placement within a failing prosthetic bypass graft, during a 41-month period, were reviewed for treatment outcome and complications. The indications for stent placement in 15 patients included severe claudication (n= 3), rest pain (n= 9), and minor or major tissue loss (n= 3). Lesions were at the proximal anastomosis (n= 6), the distal anastomosis (n= 3), or within the graft (n= 6). Results: Treatment with metallic stents was successful in all patients. There was one acute stent thrombosis, successfully treated with thrombolytic therapy. Follow-up data are available for a mean duration of 12.3 months. The mean duration of primary patency was 9.4 months with 6- and 12-month primary patency rates of 51.9% and 37.0%, respectively. The mean duration of secondary patency was 12.1 months with 6- and 12-month secondary patency rates of 80.0% and 72.7%, respectively. Two patients with discontinuous runoff and preexisting gangrene required a below-knee amputation. Six patients were revised surgically after stent placement (at a mean of 10.8 months). Three late deaths occurred during follow-up. Conclusion: Given the mortality risks of surgical revision and the reduced life expectancy of this patient population, metallic stent placement represents a viable, short-term treatment option for stenoses within or at the anastomoses of prosthetic grafts. Further evaluation is warranted to compare intragraft stent placement with surgical graft revision.     

Percutaneous transluminal angioplasty of peripheral bypass stenoses

Purpose: To assess the success of percutaneous transluminal angioplasty (PTA) in treating peripheral bypass stenoses. Methods: Patients who received a femoropopliteal or femorocrural bypass graft for limb ischemia were included in a duplex surveillance program. If duplex ultrasound revealed a short (<2 cm) severe (peak systolic velocity ratio ≥ 4.5) stenosis, patients were scheduled for arteriography and PTA. Fifty-eight peripheral bypass stenoses in 39 grafts in 37 patients were treated with PTA. The cumulative primary patency of treated stenoses was calculated. Results: During the first year after PTA 31 (53%) treated lesions remained patent, 15 (26%) lesions restenosed at a median interval of 5.0 (range 1–12) months and 4 (7%) bypasses occluded. The cumulative primary patency of 58 treated graft stenoses at 1 year was 60% [95% confidence interval (CI) 46%–74%] and 55% (95% CI 41%–70%) at 2 years. Graft body stenoses showed a better 2-year cumulative primary patency (86%; 95% CI 68%–100%) compared with juxta-anastomotic lesions (45%; 95% CI 29%–62%; p < 0.05). Conclusion: PTA is justifiable as the initial treatment of peripheral bypass stenoses. Nevertheless, the restenosis rate is rather high, especially in juxta-anastomotic lesions. Continuation of duplex surveillance after PTA and timely reintervention is recommended.     

Percutaneous Treatment of Central Venous Stenosis in Hemodialysis Patients: Long-Term Outcomes

The purpose of this study was to evaluate the long-term outcomes of endovascular treatment of central venous stenosis in patients with arteriovenous fistulas (AVFs) for hemodialysis. Five hundred sixty-three patients with AVFs who were referred for a fistulogram were enrolled in this study. Among them, 44 patients showed stenosis (n = 35) or occlusions (n = 9) in the central vein. For the initial treatment, 26 patients underwent percutaneous transluminal angioplasty (PTA) and 15 patients underwent stent placements. Periods between AVF formation and first intervention ranged from 3 to 144 months. Each patient was followed for 14 to 60 months. Procedures were successful in 41 of 44 patients (93.2%). Primary patency rates for PTA at 12 and 36 months were 52.1% and 20.0%, and assisted primary patency rates were 77.8% and 33.3%, respectively. Primary patency rates for stent at 12 and 36 months were 46.7% and 6.7%, and assisted primary patency rates were 60.0% and 20.0%, respectively. Fifteen of 26 patients with PTAs underwent repeated interventions because of restenosis. Fourteen of 15 patients with a stent underwent repeated interventions because of restenosis and combined migration (n = 1) and shortening (n = 6) of the first stent. There was no significant difference in patency between PTAs and stent placement (p > 0.05). Average AVF patency duration was 61.8 months and average number of endovascular treatments was 2.12. In conclusion, endovascular treatments of central venous stenosis could lengthen the available period of AVFs. There was no significant difference in patency between PTAs and stent placement.     

Primary stenting for complex atherosclerotic plaques in aortic and iliac stenoses

Purpose: To evaluate the efficacy of primary stenting for complex atherosclerotic plaques in aortic and iliac stenoses that are not amenable to balloon angioplasty alone. Methods: Nineteen patients with complex atherosclerotic plaques were treated with a Palmaz stent (n= 19), Wallstent (n= 1), Strecker stent (n= 1), or Memotherm stent (n= 1). A total of 22 stenoses presenting with complex plaque morphology including ulcerated plaques, ulcerated plaques with focal aneurysms, plaques with heavy calcification, severely eccentric plaques, plaques with overhanging edge, and plaques with spontaneous dissection were stented. The lesions were in the aorta (n= 1), common iliac artery (n= 19), or external iliac artery (n= 2). Results: Immediate angiography after stent placement revealed restoration of patency of the stented segment. Focal aneurysms and ulcerated areas were occluded in the follow-up angiographies obtained 4–12 weeks after the procedure. In one case with poor distal runoff and multiple complex lesions of the iliac artery, subacute occlusion occurred. Clinical and angiographic follow-up (3–46 months) revealed patency of all other stented segments. Conclusion: Primary stenting is an effective and reliable approach for complex plaques in stenoses. Patency of the arterial segment with a smooth lumen can be created without the risk of acute complications such as distal embolization, dissection, or occlusion.     

Budd-chiari syndrome caused by obstruction of the hepatic inferior vena cava: Immediate and 2-year treatment results of transluminal angioplasty and metallic stent placement

Purpose: To assess the usefulness of percutaneous transluminal angioplasty (PTA) and expandable metallic stent (EMS) placement for treatment of Budd-Chiari syndrome (BCS). Methods: Thirty-two patients with BCS were treated by PTA alone or by PTA and EMS placement. Among the 32 patients, a membranous obstruction was found in 24 and a segmental stenosis or occlusion in 8 patients. The follow-up period for PTA was 38<+>–<+>68 months (mean 52.2 months); for EMS it was 20<+>–<+>36 months (mean 24.3 months). Results: Twenty-one patients underwent PTA as the primary treatment. Of these, one patient died of disseminated intravascular coagulation shortly after the procedure; 20 had good to excellent initial angiographic and clinical results. Of the 20, restenosis or reocclusion developed in 10 patients (48%), all before 27 months; 8 patients (38%) became symptomatic, and 2 remained symptom-free for a total recurrent obstruction rate of 50%. The EMS group of 17 patients included 11 patients who underwent primary stenting and 6 patients with secondary stenting after recurrence following primary PTA; restenosis was demonstrated in only 2 patients (12%). Conclusions: We conclude that PTA alone produces excellent short-term results and about 50% sustained patency after 2 years in patients with BCS; therefore it should remain the procedure of first choice. Stents should be reserved for primary or secondary PTA failures.     

Percutaneous Endoluminal Stent and Stent-Graft Placement for the Treatment of Femoropopliteal Aneurysms: Early Experience

Purpose: To determine the efficacy of percutaneous endoluminal stents and stent-grafts for the treatment of isolated femoropopliteal aneurysms. Methods: Seven men (age 51–69 years) with femoropopliteal occlusions (n= 6) related to aneurysms and a patent femoropopliteal aneurysm (n= 1) were treated percutaneously. In two patients uncovered Wallstents and in five patients polyester-covered nitinol stents were implanted. Assessment was performed with Doppler ultrasound and duplex ultrasonography 24 hr, 1, 3, 6, 12, and 24 months after the intervention. Additionally, intraarterial angiography was performed at 6 months. Results: Stent placement succeeded in all cases. No immediate adjunctive surgical treatment was necessary. Ankle-brachial index (ABI) improved from 0.29 ± 0.29 (SD) before to 0.78 ± 0.23 (SD) 24 hr after the intervention. One patient was lost to follow-up. Stent-graft occlusion occurred in four patients: after 2 days (n= 1), 1 month (n= 2), and 3 months (n= 1). One of the patients, whose stent occluded at 1 month, underwent successful recanalization with local fibrinolysis therapy. Three of the seven, all with three-vessel run-off, demonstrated patency of the stent, which was assessed by duplex ultrasonography at 29, 31, and 34 months. Breaking of the stent struts or significant stent migration was not observed. Conclusions: These results in a small number of patients warrant further investigation to evaluate the role of percutaneous stents in femoropopliteal aneurysms. Until further data of clinical studies are available, this method cannot be recommended, and it cannot replace surgical treatment.     

Early and long-term results of subclavian angioplasty in aortoarteritis (takayasu disease): Comparison with atherosclerosis

Purpose: To compare the early andlong-term outcomes of subclavian artery angioplasty in patients with aortoarteritis and atherosclerosis. Methods: Sixty-one subclavian artery angioplasties were performed in 55 consecutive patients with aortoarteritis (n= 32) and atherosclerosis (n= 23) between 1986 and 1995. An arch aortogram followed by a selective subclavian artery angiogram was done to profile the site and extent of the lesion, its relation to the vertebral artery, and the distal circulation. Percutaneous transluminal angioplasty (PTA) was performed via the femoral route for 56 stenotic lesions and 5 total occlusions. Results: PTA was successful in 52 (92.8%) stenotic lesions and 3 (60%) total occlusions. Three patients (5.4%) had complications, that could be effectively managed nonsurgically. Compared with atherosclerosis, patients with aortoarteritis were younger (27.4 ± 9.3 years vs 54.5 ± 10.5 years; p < 0.001), more often female (75% vs 17.4%; p < 0.001), gangrene was uncommon (0% vs 17.4%; p < 0.05), and diffuse involvement was seen more often (43.8% vs 4.4%; p < 0.001). The luminal diameter stenoses were similar before PTA (88.6 ± 9.7% vs 89.0 ± 9.1%; p= NS). Higher balloon inflation pressure was required to dilate the lesions of aortoarteritis (9.9 ± 4.6 ATM vs 5.5 ± 1.0 ATM; p < 0.001). This group had more residual stenosis (15.5 ± 12.4% vs 8.3 ± 9.4%; p < 0.05) after PTA. There were no neurological sequelae, even in PTA of prevertebral lesions. On 3–120 months (mean 43.3 ± 28.9 months) follow-up of 40 patients, restenosis was more often observed in patients with aortoarteritis, particularly in those with diffuse arterial narrowing. These lesions could be effectively redilated. Clinical symptoms showed marked improvement after successful angioplasty. Conclusion: Subclavian PTA is safe and can be performed as effectively in aortoarteritis as in atherosclerosis, with good long-term results. Long-term follow-up shows that it provides good symptomatic relief.     

Percutaneous transluminal angioplasty and enclosed thrombolysis versus percutaneous transluminal angioplasty in the treatment of femoropopliteal occlusions: Results of a prospective randomized trial

Purpose: To determine whether percutaneous transluminal angioplasty (PTA) and enclosed thrombolysis (ET) is superior to PTA alone in the treatment of femoropopliteal occlusions. Methods: Twenty-five patients with 5–15-cm-long occlusions in the femoropopliteal segments, with otherwise normal run-in arteries and at least one normal tibioperoneal artery to the foot, were randomized to ET/PTA or PTA alone. Ankle brachial systolic index (ABI) was measured before the procedure and at 24 hr and 12 months after the procedure, when a duplex scan was also carried out. End points in the study were patency at, or repeat intervention before, 12 months. Results: Procedures were successful in 23 of 25 patients. There was one immediate occlusion of tibioperoneal arteries, and one early reocclusion of a reopened segment in the ET/PTA group. There was one early reocclusion in the PTA group. At 12 months patency was 70% and 69.2% in the ET/PTA and PTA groups respectively. Covariant analysis showed no significant difference in ABI between the two groups at any of the three measurement times. Conclusion: This trial demonstrated no difference between ET/PTA and PTA alone in femoropopliteal occlusions associated with normal proximal arteries and at least one normal tibioperoneal artery.     

PTA Versus Carbofilm-Coated Stents in Infrapopliteal Arteries: Pilot Study

Purpose: To determine the primary success and short-term patency of stent application as a primary treatment modality for high-grade lesions of the infrapopliteal arteries compared with treatment with percutaneous transluminal angioplasty (PTA) in critical limb ischemia in a randomized prospective study. Methods: Endovascular therapy was performed on 95 lesions in 51 patients (mean age 72.0 years, range 47–80 years) who presented clinically with Fontaine stages III and IV. One patient underwent treatment in both limbs. After angiographic lesion identification, patients were randomized for treatment by PTA (53 lesions in 27 patients) or stent application (42 lesions in 24 patients). Follow-up by clinical investigation and conventional angiography or spiral CT angiography was performed in 37 patients (57 lesions) 6 to 12 months after the procedure, or when clinically indicated. Evaluation was performed by two observers, double-blinded, with thresholds for lesion restenosis of 50% and 70%. Statistical evaluation was performed on a lesion basis by Kaplan–Meier estimated probability rates, and log-rank and Wilcoxon tests. The primary endpoint was the angiographic patency rate of treated lesions. Results: The inter-reader agreement was high (κ = 0.82). For the stent group the cumulative primary patency at 6 months was 83.7% at the 70% restenosis threshold, and 79.7% at the 50% restenosis threshold. For PTA, the primary patency at 6 months was 61.1% at the 70% restenosis threshold and 45.6% at the 50% restenosis threshold. Both results were statistically significant (p < 0.05). Conclusion: Infrapopliteal stent application is an effective treatment modality for high-grade lesions in chronic critical limb ischemia. Compared with PTA, higher patency rates can be expected after 6 months.     

Nonsurgical fluoroscopically guided dacryocystoplasty of common canalicular obstructions

Purpose: To assess dacryocystoplasty in the treatment of epiphora due to obstructions of the common canaliculus. Methods: Twenty patients with severe epiphora due to partial (n = 16) or complete (n = 4) obstruction of the common canaliculus underwent fluoroscopically guided dacryocystoplasty. In all cases of incomplete obstruction balloon dilation was performed. Stent implantation was attempted in cases with complete obstruction. Dacryocystography and clinical follow-up was performed at intervals of 1 week, and 3, 6, 12, and 18 months after the procedure. The mean follow-up was 6 months (range 3–18 months). Results: Balloon dilation was technically successfully performed in all patients with incomplete obstructions (n = 16). In three of four patients with complete obstruction stent implantation was performed successfully. Subsequent to failure of stent implantation in one of these patients balloon dilation was performed instead. The long-term primary patency rate in patients with incomplete obstructions was 88% (n = 14/16). In three of four cases with complete obstruction long-term patency was achieved during follow-up. Severe complications, infections, or punctal splitting were not observed. Conclusion: Fluoroscopically guided balloon dacryocystoplasty is a feasible nonsurgical therapy in canalicular obstructions with good clinical results that may be used as an alternative to surgical procedures. In patients with complete obstructions stent placement is possible but further investigations are needed to assess the procedural and long-term results.     

Comparative Efficacy of Pulse-Spray Thrombolysis and Angioplasty Versus Surgical Salvage Procedures for Treatment of Recurrent Occlusion of PTFE Dialysis Access Grafts

Purpose: To compare the efficacy of surgery versus pulse-spray thrombolysis and angioplasty in patients with recurrent thrombosis of polytetrafluoroethylene (PTFE) dialysis access grafts. Methods: We analyzed 96 consecutive interventions for thrombosed PTFE dialysis access grafts in 18 patients. Primary patency after thrombolysis and angioplasty (n= 25) was compared with primary patency following thrombectomy alone (n= 50) or thrombectomy followed by graft revision (n= 21) using life-table analysis. A Cox proportional hazards model that accounted for graft age and number of previous interventions was used to generate the relative risk for recurrent occlusion following therapy. Results: Life-table analysis showed that patency after thrombolysis and angioplasty was greater than that following thrombectomy alone (p= 0.02). After accounting for the age of the graft and the number of previous interventions (average six per patient), the relative risk for recurrent occlusion [3.0; 95% confidence intervals (CI): 1.5, 6.4] was greater for thrombectomy alone than for thrombolysis/angioplasty [0.6; CI = 0.3, 1.3]. The relative risks of repeat occlusion following thrombolysis/angioplasty [0.6; CI = 0.3, 1.3] and thrombectomy/surgical revision [1.0; CI = 0.5, 1.7] were similar. Conclusion: Outcome data from our retrospective study on recurrent thrombosis of PTFE dialysis access grafts suggest that thrombolysis/angioplasty is superior to thrombectomy alone, and equivalent to thrombectomy/surgical revision.     

External Beam Irradiation and Restenosis Following Femoral Stenting: Long-Term Results of a Prospective Randomized Study

Purpose To assess the long-term outcome of external beam irradiation (EBI) for the prevention of restenosis due to neointimal hyperplasia, following percutaneous transluminal angioplasty (PTA) and stenting of the superficial femoral artery. Methods Sixty consecutive patients with peripheral arterial disease, who were treated with “bail-out” stent implantation in the superficial femoral artery due to suboptimal PTA, were included in this study. Patients were randomly allocated into two groups, receiving either external beam irradiation (6 MV photons, total dose 24 Gy in a hypofractionated schedule) plus antiplatelet therapy (EBI group) or antiplatelet therapy alone (control group). Results No procedure-related complications occurred, and all patients of the EBI group received the full dose of 24 Gy. During the long-term follow-up, an overall statistically significant difference was demonstrated in favor of the EBI group patients, regarding both the in-stent (log-rank test, p = 0.0072) and the in-segment binary restenosis (log-rank test, p = 0.0103). The primary patency rates were also significantly better in the EBI group at specific time-points, such as in the first (74.2% vs 46.5%, p = 0.019), second (62.5% vs 33.8%, p = 0.020), and third (54.6% vs 29.0%, p = 0.039) year, respectively. Moreover, the overall clinically driven reintervention rate was significantly lower among patients of the irradiated group (log-rank test, p = 0.038). Conclusion Our long-term follow-up analysis revealed that EBI following femoral artery PTA and stenting significantly reduces restenosis and reintervention rates, while improving primary patency.     

Effect of antithrombotic agents on the patency of PTFE-Covered stents in the inferior vena cava: An experimental study

Purpose: To evaluate the efficacy of antithrombotic agents in the prevention of stenosis of polytetrafluoroethylene (PTFE)-covered stents in the venous system. Methods: Spiral Z stents covered with PTFE (PTFE-covered stents) were placed in the inferior vena cava (IVC) of 34 dogs. Nineteen dogs, used as a control group, were sacrificed at 2, 4, and 12 weeks. Fifteen dogs, previously given antithrombotic agents [cilostazol (n= 5), warfarin potassium (n= 5), cilostazol plus warfarin potassium (n= 5)] were sacrificed at 4 weeks, and then examined angiographically and histopathologically. The effect of the antithrombotic agents was compared between groups. Results: The patency rate of the antithrombotic agent group was 93% (14/15), which was higher than the control group rate of 63% (12/19). The mean stenosis rate of the patent stent at both ends and at the midportion was lower at 4 weeks in the antithrombotic agent group than in the control group. In particular, the mean stenosis rate in the cilostazol plus warfarin potassium group was significantly lower than the control group (Tukey's test, p < 0.05). The mean neointimal thickness of the patent stent at both ends and at the midportion was thinner at 4 weeks in the antithrombotic agent group than in the control group. In particular, the thickness of the neointima in the cilostazol plus warfarin potassium group was significantly decreased when compared with the control group (Tukey's test p < 0.05). At 4 weeks, endothelialization in the antithrombotic agent group tended to be almost identical to that in the control group. Conclusion: The present study suggests that administration of an antithrombotic agent is an effective way of preventing the stenosis induced by a neointimal thickening of PTFE-covered stents in the venous system.     

Endovascular treatment of atherosclerotic arterial stenoses and occlusions of the supraaortic arteries: mid-term results from a single center analysis

OBJECTIVE: To determine mid-term patency rates after endovascular treatment of supraaortic atherosclerotic arterial stenoses and occlusions using percutaneous transluminal angioplasty (PTA) and stent placement. PATIENTS AND METHODS: During a period of 83 months, 48 patients (18 female, 30 male; mean age 61 years, range 31-82 years) were included into this prospective single-center study. Fifty-five lesions of the brachial and cephalic arteries (subclavian/axillary artery n = 42, innominate artery n = 7, origin common carotid artery n = 6) were treated using PTA (n = 38), PTA plus stent (n = 11) or primary stent placement (n = 6). For anticoagulation, patients received a bolus of heparin (5000 IU) intraarterially during the intervention followed by intravenous application for 24h. At discharge, life-time application of ASA (100mg/day) was initiated. Follow-up protocol included clinical examination, colour-coded duplex ultrasound and intraarterial angiography in case of re-stenosis. RESULTS: PTA and stent placement were technically successful in all patients (100%). No major complications occurred. Of seven patients presenting with total occlusions, six were treated with stent placement. Stent implantation was also performed in all lesions located at the origin of the supraaortic arteries (n = 6). In 38 lesions, the result of PTA was satisfactory. Mean follow-up time is 22 months (range 1-83 months). During follow-up examinations, re-stenoses occurred in 10 cases (at 1 month n = 2, at 6 months n = 2, at 12 months n = 3, at 24 months n = 3). In 9 lesions, re-interventions were performed (PTA n = 7; PTA plus stent n = 2). According to Kaplan-Meier life-table analysis, cumulative primary and primary assisted patency rates are 69.5% (patients at risk n = 15; standard error 9%) and 90.6% (patients at risk n = 16; standard error 6.3%) at 20 months, respectively. CONCLUSIONS: Endovascular treatment of atherosclerotic obstructive disease in brachial and cephalic arteries is a safe procedure showing promising mid-term patency rates.     

Directional atherectomy in iliac stent failure: Clinical technique and histopathologic correlation

Purpose: To assess the feasibility and efficacy of directional atherectomy in the treatment of iliac stent stenosis or occlusion and to evaluate the histologic composition of excised atherectomy specimens. Methods: Directional atherectomy of six occluded and 10 severely stenosed iliac stents was undertaken in 12 patients at a mean interval of 28 months (range 3–69 months) after stent insertion for occlusive aortoiliac disease. In cases of stent occlusion, atherectomy was preceded by low-dose thrombolysis. In all patients stent clearance with return of femoral pulses was achieved within 24 hr and there were no significant complications. All excised specimens were sent for histologic examination. Results: Eleven patients (92%) remain symptom free with unlimited walking distance at a mean follow-up interval of 11.5 months (range 3–31 months) after treatment. Histologic examination revealed typical myointimal hyperplasia at three excision sites, intimal fibrosis at three sites, atheroma at four sites and organized thrombus at six sites. Conclusion: Atherectomy offers an effective treatment in iliac stent occlusion and restenosis with no significant adverse effects. Debulking of these lesions seems to offer a more logical approach than simple balloon angioplasty. Clinical and duplex follow-up confirms satisfactory outcome within the first year but longer-term results are not yet known. The histologic data obtained demonstrate that stent restenosis and occlusion are likely to be multifactorial, and challenge the assumption that myointimal hyperplasia is the sole cause of iliac stent occlusion.     

Differences in Endothelial Injury After Balloon Angioplasty, Insertion of Balloon-Expanded Stents or Release of Self-Expanding Stents: An Electron Microscopic Experimental Study

Purpose: To evaluate which of six different commonly available stents inserted into an artery without percutaneous transluminal angioplasty (PTA) causes the least endothelial damage. To compare the degree of endothelial injury after insertion of such a stent with injury caused by PTA. Methods: Twelve healthy pigs were used in the experiments. In the first part of the study six different types of stents were inserted into the common iliac arteries. In the second part of the study self-expanding stents with large spaces between the wires were used. PTA was performed in the contralateral iliac artery. The pigs were killed immediately after the procedure and resected specimens examined after fixation, using scanning electron microscopy. Results: All procedures but two were accomplished successfully. More endothelium was preserved after insertion of self-expanding stents with large spaces between the wires, compared with stents with small spaces and balloon-expanded stents. After insertion of self-expanding stents with large spaces, 50.1% ± 16.4% of the endothelium remained intact, compared with only 5.6% ± 7.7% after PTA. The difference was statistically significant (p < 0.001). Conclusion: Self-expanding stents with large spaces between the wires, inserted without PTA, cause less damage to the endothelium than other stents and significantly less damage than PTA.