The Safety and Effectiveness of the Prostar XL Closure Device Compared to Open Groin Cutdown for Endovascular Aneurysm Repair

OBJECTIVE

The aim of this study is to compare the outcomes of percutaneous femoral closure with the Prostar XL for endovascular aneurysm repair (EVAR) to those of open femoral cutdown, and to evaluate factors which may predict the failure of percutaneous closure.

METHODS

Patients undergoing endovascular aneurysm repair for an infrarenal abdominal aortic aneurysm between 2005 and 2013 were included. Patient characteristics, anatomic femoral artery measurements, and postoperative complications were recorded retrospectively. Operator experience was defined with a cut-off point of >30 Prostar XL closures performed. Comparisons were made per access site.

RESULTS

A total of 443 access sites were included, with percutaneous closure used in 257 cases (58.0%) and open cutdown in 186 cases (42.0%). The complication rate was 2.7% for the percutaneous and 4.3% for the open cutdown group (P = .482). No significant differences between groups were found with respect to 30-day mortality, wound infections, thrombosis, seromas, or bleeding complications. Fourteen failures (5.4%) of percutaneous closure occurred. The success rates were similar for experienced and unexperienced operators (94.2% vs 95.5%, P = .768). Renal insufficiency was more common in the failed than in the successful percutaneous closure group (64.3% vs 24.7%, P = .003). Common femoral artery calcification or diameter, BMI, sheath size, or operator experience did not predict failure. No further complications were seen in follow-up CT at 1-3 years postoperatively.

CONCLUSION

The use of the Prostar XL is safe compared to open cutdown. The success rate is 94.6%. Operator experience, sheath size, obesity, or femoral artery diameter or calcification do not appear to predict a failure of percutaneous closure. Complications seem to occur perioperatively, and late complications are rare.

Possible implications of device-specific variability in post-endovascular aneurysm repair sac regression and endoleaks for surveillance categorization

OBJECTIVE

Significant sac regression during early surveillance has been shown to best predict reintervention-free long-term surveillance after endovascular aneurysm repair (EVAR). Furthermore, a persistent endoleak has been related to a worse outcome. Individualized surveillance algorithms based on these findings have been suggested. There are no studies comparing the performance of different stent grafts regarding sac regression, the presence of type II endoleaks, and their possible implications for individualized surveillance. The objective of this study was to evaluate device-specific differences and how these may affect patient categorization for surveillance.

METHODS

Patients were treated electively with standard EVAR between 2005 and 2015 using three different devices (Zenith by Cook, Excluder by Gore, and Endurant by Medtronic). The data were reviewed retrospectively until 2020. Patients' computed tomography angiographies (CTAs) at 30 days and at 2 years were analyzed for freedom from endoleaks and for sac regression of ≥5 mm. Reinterventions during long-term surveillance were counted. Patients were categorized according to the presence of any endoleak and sac regression at 30 days and 2 years, and the probability of reintervention-free long-term surveillance was evaluated based on these findings.

RESULTS

A total of 435 patients were treated for an abdominal aortic aneurysm with EVAR during the study period. At 30 days, 80.0% (n = 339) of the patients were free from endoleaks, and at 2 years, 78.9% (n = 273) were free from endoleaks. There was a significant difference in endoleak rate at 30 days and 2 years between the devices (P < .001 and P = .001). There was no significant difference in sac regression between the devices at 2 years (P = .096). The categorization at 30 days based on endoleak status had a sensitivity of 44.9%, specificity of 87.4%, and negative predictive value of 84.1% for finding a reintervention-requiring complication during long-term follow-up. The corresponding figures at 2 years were 63.3%, 91.4%, and 89.4%, respectively. The combination of freedom from endoleaks and sac regression of ≥5 mm in the 2-year CTA best predicted an uneventful long-term surveillance. Patients who met this criterion had a 95.6% probability (negative predictive value) of having a reintervention-free long-term surveillance.

CONCLUSIONS

There are significant differences in the prevalence of endoleaks between devices at 30 days and 2 years, but there is no difference in sac regression. Patients with sac regression of ≥5 mm and no endoleaks in the 2-year CTA can be safely categorized for infrequent surveillance regardless of the stent graft model that has initially been used.

Routine Inferior Mesenteric Artery Embolisation is Unnecessary Before Endovascular Aneurysm Repair

OBJECTIVE

A type II endoleak is the most common complication during surveillance after endovascular aneurysm repair (EVAR), and a patent inferior mesenteric artery (IMA) is a known risk factor for an endoleak. The effect of routine IMA embolisation prior to EVAR on overall outcome is unknown. The aim of the study was to compare two strategies: routine attempted IMA embolisation prior to EVAR (strategy in centre A) and leaving the IMA untouched (strategy in centre B).

METHODS

Patients were treated with EVAR in two centres during the period 2005 - 2015, and the data were reviewed retrospectively. The primary endpoints were re-intervention rate due to type II endoleaks and the late IMA embolisation rate. Secondary endpoints included EVAR related re-intervention, sac enlargement, aneurysm rupture, and open conversion rates.

RESULTS

Strategy A was used to treat 395 patients. The IMA was patent in 268 (67.8%) patients, and embolisation was performed in 164 (41.5%). The corresponding figures for strategy B were 337 patients with 279 (82.8%) patent IMAs, two (0.6%) of which were embolised. The mean duration of follow up was 70 months for strategy A and 68.2 months for strategy B. The re-intervention rates due to a type II endoleak were 12.9% and 10.4%, respectively (p = .29), with no significant difference in the rate of re-interventions to occlude a patent IMA (2.0% and 4.7%, respectively; p = .039). The EVAR related re-intervention rate was similar, regardless of strategy (24.1% and 24.6%, respectively; p = .93). Significant sac enlargement was seen in 20.3% of cases treated with strategy A and in 19.6% treated with strategy B (p = .82). The rupture and conversion rates were 2.5% and 2.1% (p = .69) and 1.0% and 1.5% (p = .40), respectively.

CONCLUSION

The strategy of routinely embolising the IMA does not seem to yield any significant clinical benefit and should therefore be abandoned.

Long-term outcomes of endovascular aneurysm repair according to instructions for use adherence status

OBJECTIVE

Endovascular aneurysm repair (EVAR) has become a standard treatment method for abdominal aortic aneurysms (AAA). Endovascular device manufacturers have defined specific anatomic criteria for aneurysm characteristics to be observed as instructions for use (IFU) with specific grafts. In clinical practice, the prevalence of performing EVAR outside the IFU is high. This study aims to determine the impact of IFU criteria non-adherence on outcomes.

METHODS

Patients undergoing EVAR for an infrarenal AAA between 2005 and 2013 were included. IFU non-adherence was defined as any violation of device-specific IFU criteria and was compared to IFU adherence. Primary outcomes were all-cause mortality, aneurysm-related mortality, AAA ruptures, graft-related adverse events (GRAEs), including limb-related adverse events, and type Ia endoleaks. Secondarily, the aim was to study whether the prevalence of EVAR performed outside the IFU has increased over time.

RESULTS

A total of 258 patients were included, 144 (55.8%) of whom were treated according to the IFU criteria and 114 (44.2%) outside the criteria. In the IFU non-adherence group, all-cause mortality (HR 1.39, 95% CI 1.02-1.89, p = .037) and aneurysm-related mortality (HR 5.1, 95% CI 1.4-18.6, p = .015) were higher, as were the incidences of AAA ruptures (HR 5.4, 95 % CI 1.1-26.6, p = .036) and GRAEs (HR 1.7, 95% CI 1.1-2.8, p = .025). No significant association was found between type Ia endoleak and neck-related IFU or limb-related adverse events and iliac-related IFU. However, neck length was a risk factor for a type Ia endoleak (HR 18.2, 95% CI 6.3-52.2, p < .001), aneurysm-related mortality (HR=8.7, 95% CI 1.8-41.6, p = .007), rupture (HR= 21.7, 95% CI 2.8-166, p = .003), and GRAEs (HR 4.4, 95% CI 2.0-9.7, p < .001). An IFU violation regarding the neck angulation was also a risk factor for all-cause mortality (HR 2.0, 95% CI 1.1-3.7, p = .032), aneurysm-related mortality (HR 7.6, 95% CI 1.4-42.8, p = .021), AAA rupture (HR 79.4, 95% CI 6.3-999, p = .001), and GRAEs (HR 4.3, 95% CI 1.9-9.5, p < .001). The prevalence of EVAR performed outside the IFU did not increase over time.

CONCLUSIONS

Performing EVAR outside the IFU has a negative effect on outcomes, including all-cause mortality, aneurysm-related mortality, ruptures, and graft-related adverse events. Neck angulation and neck length seem to be the most crucial aneurysm characteristics.

The effect of suprarenal graft fixation during EVAR on short- and long-term renal function

OBJECTIVE

The effect of suprarenal fixation (SR) compared to infrarenal fixation (IR) on renal function during endovascular aneurysm repair (EVAR) remains controversial. This study aims to compare the renal outcomes between fixation types in short- and long-term follow-up.

METHODS

Patients undergoing EVAR for infrarenal abdominal aortic aneurysm between 2005 and 2013 were included. Estimated glomerular filtration rate (eGFR) was measured at baseline and during a follow-up of 5 years. A decline in renal function was defined as a ≥ 20% decrease in eGFR. Changes in eGFR were compared between SR and IR groups at 1-7 days, 30 days, and 1-5 years postoperatively. Preoperative renal insufficiency was defined as eGFR < 60mL/min/1.73m², and those patients were included in the subanalyses.

RESULTS

A total of 358 patients were included. Among these, 267 (74.6%) had SR and 91 (25.4%) had IR fixation. A decline in renal function occurred more commonly after SR than after IR in 1-7 days postoperatively (p = .009), but no difference was noticed at 30 days and 1-5 years. Regardless of the fixation method, renal function steadily decreased steadily over time after EVAR (estimate -3.13 per a year, 95% confidence interval -3.40- -2.85, p < .001). Patients with pre-existing renal insufficiency were included in subgroup analyses, and those with SR were more often found to have a decline in eGFR 5 years postoperatively than their counterparts with IR (59.5% vs 20.0%, p = .036).

CONCLUSION

An immediate postoperative decline in renal function was seen more often after SR fixation than IR fixation but this difference was transient. SR fixation is a safe method for patients with normal renal function. Long-term results seems to favor IR over SR in patients with pre-existing renal insufficiency.

Postoperative imaging follow-up at 2 years as a predictor of long-term outcomes after endovascular aneurysm repair

OBJECTIVE

Lifelong imaging follow-up remains the reference standard after endovascular aneurysm repair (EVAR). Because the number of EVARs has been increasing, an individually optimized follow-up protocol is desirable. The aim of the present study was to investigate the possibility of creating such a protocol by evaluating patients' follow-up images and to compare the findings with their freedom from reintervention and abdominal aortic aneurysm (AAA) rupture.

METHODS

From 2000 to 2010, 282 patients with an AAA had undergone elective EVAR with the Zenith stent-graft. The patients were followed up annually until the end of 2019. The patients were categorized into two groups according to the presence of any endoleak or sac shrinkage at 2 years. Group A included those with no detectable endoleak plus aneurysm sac shrinkage of ≥5 mm (n = 137; 63%), and group B included those with any type of endoleak and/or no significant aneurysm sac shrinkage (<5 mm; n = 82; 37%).

RESULTS

The mean follow-up was 83 months (range, 0-229 months), and the overall survival at 2 years was 84% (n = 237). No significant difference was found in overall survival between groups A and B (P = .73). However, a significant difference was found in freedom from AAA rupture at 12 years, favoring group A (group A, 100%; group B, 91%; P = .002). Furthermore, in group A, the freedom from reintervention was 95% at 12 years compared with only 31% in group B (P < .001). The sensitivity of the categorization was 89% and the specificity was 74% for the finding of a complication requiring a reintervention during long-term follow-up.

CONCLUSIONS

Patients without an endoleak and a reduction of ≥5 mm in aneurysm size at 2 years had significantly fewer late reinterventions and ruptures during long-term follow-up compared with their counterparts using the Zenith stent-graft (Cook Medical, Bloomington, Ind). This finding suggests that, for these patients, the follow-up interval can be personalized and safely extended after 2 years.

Overall outcome after endovascular aneurysm repair with a first-generation stent graft (Vanguard): A 20-year single-center experience

OBJECTIVE

The problems with first-generation stent grafts for endovascular aneurysm repair are well known, but their long-term outcome remains to be established. The purpose of the study was to characterize the outcome of patients treated for abdominal aortic aneurysm (AAA) with a first-generation stent graft, Vanguard (Boston Scientific, Natick, Mass), in a single academic center with a follow-up of up to 20 years.

METHODS

There were 48 AAA patients electively treated with a Vanguard stent graft between February 1997 and November 1999. The patients were monitored annually until the end of 2018. The outcomes were overall survival and the number of graft-related complications and reinterventions.

RESULTS

The mean age was 70 years (range, 54-85 years), and the mean follow-up was 107 months (range, 6-262 months). All stent grafts were successfully implanted, but 90% of the patients encountered graft-related complications during follow-up. The most common complications were endoleaks (type I, 27%; type II, 29%; type III, 31%), stent fracture (46%), graft thrombosis (31%), and migration (40%). A total of 40 (83%) patients required a secondary procedure during long-term follow-up. The endovascular method for treating the complication was successful in 73 (87%) of 84 cases. There were no primary conversions, but 10 patients (21%) required a late conversion. In five cases, the complications required relining with a newer device. There were four AAA ruptures (8.3%), two of them fatal. The cumulative overall survival rates were 94%, 69%, 33%, 15%, and 13% at 1 year, 5 years, 10 years, 15 years, and 20 years, respectively.

CONCLUSIONS

The use of the Vanguard, a first-generation stent graft, was associated with multiple graft-related complications. However, these complications could mainly be treated by endovascular means. The Vanguard stent graft is a good example of how new technology can cause unpredictable problems that can magnify the workload and endanger the patient's well-being even decades after the initial procedure.

Oral Dipyridamole-Associated Circulatory Collapse

Extended-release dipyridamole plus aspirin is widely used for secondary prevention of ischemic stroke, although the molecular pharmacodynamics of dipyridamole are not completely determined. Adverse effects of fixed-dose combination of aspirin and dipyridamole include headache, bleeding, and gastrointestinal events. Previously, intravenous infusion of dipyridamole in cardiac stress testing has been associated with cardiogenic shock and pulmonary edema. Herein, we report a case study of a 72-year-old man, presented with a transient ischemic attack who suffered a circulatory collapse after an oral dose of 200 mg extended-release dipyridamole. The possible molecular mechanisms of dipyridamole on the cardiovascular system are reviewed. This is the first case report of a circulatory collapse induced by an oral intake of dipyridamole.

Hybrid Repair of Thoracoabdominal Aortic Aneurysms Is a Durable Option for High-Risk Patients in the Endovascular Era

Objective:

To report our long-term experience in using the hybrid technique in complex thoracoabdominal aortic aneurysms (TAAAs).

Methods:

Between March 2005 and September 2013, 10 patients with TAAA underwent hybrid procedures with open renovisceral revascularization and thoracoabdominal aortic endografting. Patients were analyzed retrospectively.

Results:

Six men and 4 women with a mean age of 66 years (range 54-81 years) were treated electively during the study period. All 4 visceral vessels were revascularized in 8 patients, whereas 1 patient underwent 3-vessel revascularization and another 2-vessel revascularization. The primary technical success rate was 100%. Eight of the procedures were single staged, and the 2 most recent cases were performed in 2 stages. Perioperative and 30-day mortality was 0%. The mean follow-up was 55 months (4-133 months). None of the patients died due to aortic complications. Major complications included paraplegia (10%, n = 1) and bowel ischemia (n = 1). Postoperative cerebrospinal fluid (CSF) pressure and mean arterial pressure measurements were systematically monitored and corrected. The CSF drainage solved another 4 cases of paraparesis. Three patients required postoperative dialysis, but none of them required permanently. Postoperative spinal cord ischemia and renal complications accumulated in extensive TAAA cases. One renal graft was occluded 45 days after the initial procedure but was successfully treated with thrombolysis. One type I and 1 type III endoleak were noted and successfully treated with an additional stent graft. Two cases of type II endoleak were detected—one with a growing aneurysm sac was treated successfully and another showed no growth and further procedures were abandoned after 2 embolization attempts. In long-term follow-up, 90% of the aneurysms showed shrinkage by a mean of 23 mm (range 7-45 mm).

Conclusion:

The results of hybrid repair on high-risk patients with complex TAAAs are encouraging, and this approach is a valuable alternative when branched and fenestrated endovascular techniques are not considered an option.

Randomized clinical trial comparing surgery, endovenous laser ablation and ultrasound-guided foam sclerotherapy for the treatment of great saphenous varicose veins

Background

Endovenous ablation techniques and ultrasound‐guided foam sclerotherapy (UGFS) have largely replaced open surgery for treatment of great saphenous varicose veins. This was a randomized trial to compare the effect of surgery, endovenous laser ablation (EVLA) (with phlebectomies) and UGFS on quality of life and the occlusion rate of the great saphenous vein (GSV) 12 months after surgery.

Methods

Patients with symptomatic, uncomplicated varicose veins (CEAP class C2–C4) were examined at baseline, 1 month and 1 year. Before discharge and at 1 week, patients reported a pain score on a visual analogue scale. Preoperative and 1‐year assessments included duplex ultrasound imaging and the Aberdeen Varicose Vein Severity Score (AVVSS).

Results

The study included 214 patients: 65 had surgery, 73 had EVLA and 76 had UGFS. At 1 year, the GSV was occluded or absent in 59 (97 per cent) of 61 patients after surgery, 71 (97 per cent) of 73 after EVLA and 37 (51 per cent) of 72 after UGFS (P < 0·001). The AVVSS improved significantly in comparison with preoperative values in all groups, with no significant differences between them. Perioperative pain was significantly reduced and sick leave shorter after UGFS (mean 1 day) than after EVLA (8 days) and surgery (12 days).

Conclusion

In comparison with open surgery and EVLA, UGFS resulted in equivalent improvement in quality of life but significantly higher residual GSV reflux at 12‐month follow‐up.

Foam less effective

Long-Term Experience of Endovascular Repair for Thoracic Aortic Aneurysms and Dissections

Purpose:

To report the long-term results of thoracic endovascular aortic repair (TEVAR) in both elective and emergency cases of thoracic aortic aneurysm (TAA) and type B dissection.

Material and Methods:

A prospective single-center study of 78 TEVAR patients treated between February 1998 and February 2013. Stent-graft implantation was performed in 51 (65%) patients for TAA (43 elective and 8 emergency cases) and in 27 (35%) patients for type B dissection (11 elective and 16 emergency cases). Short- and long-term results were evaluated, and a subgroup of patients with left subclavian artery (LSA) coverage was also analyzed.

Results:

The patients were followed for a mean of 55 months (1-160 months). The technical success rate was 81% and 30-day mortality 6.4% (n = 5). The stroke rate was 7.7% (n = 6) and permanent paraparesis 2.6% ( n = 2). In follow-up, there were 28 (36%) primary (15 type I and 13 type II) and 10 secondary endoleaks (8 type I and 2 type II). Multivariate analysis showed no significant predictive factors for developing a type I endoleak. Secondary interventions were required in 24% of the patients. There was 1 late thoracic aortic rupture and 1 late conversion (1.3%). Patients with LSA coverage had a higher incidence of stroke (12.5% vs 4.3%, P = .18) and paraparesis (3.1% vs 2.2%, P = .79) compared to those without LSA coverage, although this difference was not statistically significant. Stroke rates were significantly higher in patients treated in an emergency setting ( P = .048).

Conclusion:

Thoracic endovascular aortic repair is a relatively safe and effective therapy for different aortic pathologies with good long-term success. The risk of stroke and paraparesis is notable whether the LSA is covered, and strokes clearly accumulate in the emergency setting. A type I endoleak is the most common complication, but there are no predictive factors for its development.

Comparison of above-the-knee prosthetic femoro-popliteal bypass versus percutaneous transluminal angioplasty and stenting for treatment of occlusive superficial femoral artery disease

Background and Aims:

Treatment of occlusive femoro-popliteal artery disease has changed during the last decade because of intensive development of endovascular technology. The aim of this study was to evaluate patient treated endovascularly or surgically for femoro-popliteal atherosclerotic lesions and to assess perioperative and mid-term outcome.

Material and Methods:

This is a retrospective analysis of consecutive patients who had undergone prosthetic above-the-knee femoro-popliteal bypass or percutaneous transluminal angioplasty and stenting of superficial femoral artery stenosis or occlusion at Tampere University Hospital, Finland, between January 2007 and December 2009. Patients who were alive were re-evaluated in 2010. Primary and secondary patency and outcomes were assessed.

Results:

A total of 131 patients were treated; surgically 63 patients (69 procedures) and endovascularly 68 patients (74 procedures). The mean follow-up time was 17 months (SD ± 13 months). In the late follow-up visit, 8 (18%) patients in the bypass group suffered from claudication and 9 (20%) from critical limb ischemia. The corresponding figures for the endovascular group were 20 (36%) and 8 (20%), respectively. The primary patency was 60% at 2 years in the bypass group and 73% in the endovascular group (p = 0.092); the primary assisted patency was 62% versus 76%, respectively (p = 0.068). The secondary patency was 74% in the bypass group versus 79% in the endovascular group (p = 0.487).

Conclusions:

According to current results following TASC II guideline, satisfied overall mid-term results can be achieved in the treatment of superficial femoral artery atherosclerotic disease.

Dexamethasone-eluting vascular stents

Percutaneous transluminal angioplasty (PTA) with stenting is widely used in the treatment of vascular disorders, but restenosis remains a significant problem. Drug-eluting stents (DES) have been developed as an attempt to reduce the intimal response leading to restenosis. Drugs used in DES include mainly immunosuppressive and anti-proliferative compounds. Glucocorticoids are also an interesting possibility for those purposes because they have anti-proliferative effects in vascular smooth muscle cells and down-regulate the production of cytokines and growth factors driving inflammation and fibrosis. In this MiniReview, feasibility and safety of drug-eluting metal and biodegradable vascular stents are discussed with special emphasis on dexamethasone-eluting stents.

Challenging treatment of multiple late complications after endovascular aneurysm repair

BACKGROUND

To report a case of multiple additional procedures after successful endovascular treatment of abdominal aortic aneurysm.

METHODS

An endovascular abdominal aortic aneurysm repair with a bifurcated aortic Vanguard endograft successfully performed in 1999 resulted in multiple complications, including endoleaks and a row separation, treated endovascularly. Subsequently, tuberculosis sepsis and prosthesis infection resulted in long-term antibiotic treatment. Additional graft leaks, aneurysm sack growth, and sack ruptures were also treated endovascularly because the patient consistently denied open repair. Endovascular procedures, however, did not solve the problem, turning to be increasingly challenging. The patient finally approved open graft removal and aortobifemoral reconstruction that were successfully performed 11 years after the initial endograft implantation.

RESULTS

The patient has recovered from surgery well and is asymptomatic. No evidence of bacterial colonization was found according to the specimen taken during the laparotomy.

CONCLUSION

Vanguard and other first-generation aortic endografts are associated with high incidence of complications and reinterventions. Open surgery is a method of choice in similar cases.

[Subclavian steal syndrome]

Subclavian steal syndrome is a circulatory disorder usually caused by atherosclerosis and accompanied by ischemic symptoms of the vertebrobasilar region and the hand. In many cases, significant vascular lesions are found also in other arteries. In more than 80% of cases the blood vessel lesion is on the left, and a significant stenosis or occlusion causes an inter-arm pressure gradient of > 20 mmHg, resulting in retrograde blood flow of the ipsilateral vertebral artery. In local stenosis, conservative treatment can be combined with an intravascular procedure, and in occlusions or other arterial lesions requiring operative treatment, with bypass surgery.

Drug-eluting bioabsorbable stents - an in vitro study

The aim of this study was to investigate the drug elution properties of novel drug-eluting bioabsorbable stents in vitro with four different drugs: dexamethasone, indomethacin, simvastatin and ciprofloxacin. Braided stents of poly-lactic acid (96l/4d) fibers were coated with a solution containing the appropriate bioabsorbable polymer and drug, with acetone as the solvent. Two different drug concentrations for both non-sterile and gamma sterilized stents were used for dexamethasone and indomethacin. For ciprofloxacin and simvastatin, only one drug dose was used. The stents were placed in sodium-phosphate-buffered saline in a shaking incubator (pH 7.4, +37 degrees C) and the eluted drug was measured periodically using an ultraviolet spectrometer. The drugs were hydrophobic to different degrees, as demonstrated by their various speeds of elution. In general, the higher the drug load in the stent, the faster the drug elution and the more hydrophilic the elution profile. In the cases of dexamethasone, indomethacin and ciprofloxacin, the sterilization decreased the drug elution rate slightly and the elution started earlier. However, in the case of ciprofloxacin, the gamma sterilization increased the drug elution rate slightly. Sustained elution was achieved for all four drugs. It was also evident that both the concentration and the hydrophility of the drug had a great influence on the drug elution profile. Gamma sterilization modified the drug elution profiles of dexamethasone, indomethacin and simvastatin, but had little effect on the drug elution profile of ciprofloxacin compared to three other drugs.

Single-center experience with foam sclerotherapy without ultrasound guidance for treatment of varicose veins

BACKGROUND

Varicose veins are a common disorder and many treatment methods are available.

OBJECTIVE

The aim of this study was to evaluate the short-term efficacy of foam sclerotherapy and the safety of performing the treatment in an outpatient clinic without ultrasound guidance. METHODS This was a prospective, nonrandomized study with foam sclerotherapy. All the patients were assessed before and after the procedure with a CEAP (Clinical, Etiology, Anatomy, Pathology) class and clinical score. At the same visit, duplex scanning was performed to evaluate the anatomic distribution of the varicose disease. The mean age of the patients was 49.2 years (SD,+/-10.6 years; median, 50.0 years). Altogether 41% of the legs had undergone a previous operation and 24% were recurrences. The follow-up time was 3 months.

RESULTS

Twenty-five patients with 27 legs were treated successfully using foam sclerotherapy without ultrasound guidance. Twenty-one cases (78%) involved the great saphenous vein and 6 cases (22%) involved the small saphenous vein. The mean bandage time was 7.7 days (SD,+/-2.50 days; median, 8.50 days). The CEAP score decreased 73% after the procedure from 2.61 (SD,+/-0.80; median, 2.0) to 0.71 (SD,+/-0.95; median, 0; p<.001). and the mean clinical score decreased 45% from 4.45 (SD,+/-1.96; median, 4.0) to 2.46 (SD,+/-1.50; median, 2.0; p<.001), respectively. Three months after the treatment, duplex scanning showed saphenofemoral reflux in 63% of the legs and saphenopopliteal reflux in 40% of the legs. The most common complication was postoperative thrombophlebitis (66%). Other minor complications included pain (38%) and hematoma (4%). There were no major complications. Subjectively, 71% of the patients assessed the procedure as good or excellent and 29% as acceptable or poor.

CONCLUSION

Foam sclerotherapy is also an effective and safe procedure when performed without duplex guidance. Thrombophlebitis is frequent when using a high concentration of polidocanol and a short bandage time. The high frequency of saphenofemoral and saphenopopliteal junction reflux after the procedure can have a negative effect on the long-term results.

Tissue biocompatibility of new biodegradable drug-eluting stent materials

Drug-eluting stents are a recent innovation for endovascular and endourethral purposes. The aim of this study was to assess the biocompatibility of new biodegradable drug-eluting stent materials in vivo. Rods made of SR-PLDLA (self-reinforced poly-96L,4D: -lactic acid) covered with P(50L/50D)LA and rods made of 96L/4D SR-PLA and covered with P(50L/50D)LA including indomethacin 3.3 microg/mm(2)or dexamethasone 1.5 microg/mm(2), were inserted into the dorsal muscles of 20 rabbits serving as test animals. Rods made of silicone and organotin-positive polyvinylchloride were used as negative and positive controls. The animals were sacrificed after 1 week, 1 month, 2 months or 4 months. Histological changes attributable to the operative trauma were seen in all specimens at 1 week and 1 month. At 2 months both dexamethasone and indomethacin induced less fibrosis than the plain SR-PLDLA covered with P(50L/50D)LA without drug. At 4 months dexamethasone induced both chronic inflammatory changes and foreign body reaction, whereas the reactions in the indomethacin and drug-free plain SR-PLDLA groups were insignificant. The new biodegradable drug-eluting stent materials are highly biocompatible. Drug-eluting biodegradable stents may offer a promising new treatment modality for vascular and urethral diseases. However, further studies are needed to demonstrate their feasibility and efficacy.

Drug-Eluting Biodegradable Poly-D/L-Lactic Acid Vascular Stents:An Experimental Pilot Study

PURPOSE

To evaluate in vivo a new drug-eluting biodegradable vascular stent with respect to biocompatibility, neointimal hyperplasia formation, and reliability.

METHODS

Self-expanding biodegradable poly-96L/4D-lactic acid (PLA) stents with 2 drugs (PLA + dexamethasone [DEX] and PLA + simvastatin [SIM]) and 2 different coatings (PLA + P(D,L)LA and PLA + polycaprolactone [PCL]) were compared with a self-expanding stainless steel Wallstent. The stents were implanted in both common iliac arteries of 8 pigs. Prior to sacrifice at 1 month, angiography was performed to determine patency. Specimens were harvested for quantitative histomorphometry; vascular injury and inflammation scores were assigned to the stented iliac segments.

RESULTS

All stented arteries were angiographically patent. The mean luminal diameter (3.05 mm) and area (30.36 mm2) of DEX-eluting PLA stents were decreased compared to other stents (PLA + P(D,L)LA: 3.66 mm and 43.92 mm2; PLA + SIM: 4.21 mm and 56.48 mm2; PLA + PCL: 4.19 mm and 54.64 mm2; Wallstent: 5.01 mm and 81.19 mm2). Wallstents and DEX-eluting PLA stents induced minimal intimal hyperplasia: PLA + DEX: 0.16 mm, PLA + P(D,L)LA: 0.35 mm, PLA + SIM: 0.33 mm, PLA + PCL: 0.29 mm, and Wallstent: 0.18 mm. The vascular injury scores demonstrated only mild vascular trauma for all stents. Only mild to moderate inflammatory reaction was noted around stent struts with a vascular inflammation score.

CONCLUSIONS

Biodegradable polymer stents appear to be biocompatible and reliable, causing minimal neointimal hyperplasia. Furthermore, the new biodegradable poly-D/L-lactic acid stent can be used as a local drug delivery vehicle. The DEX-eluting PLA stent reduces neointimal hyperplasia. The findings show a need for further investigation to prove the efficacy and safety of this new biodegradable drug-eluting stent.

Biodegradable self-expanding poly-L/D-lactic acid vascular stent: a pilot study in canine and porcine iliac arteries

PURPOSE

To report results of an in vivo pilot study to evaluate the biocompatibility and delivery system of a new biodegradable vascular stent and validate the study design.

METHODS

Two self-expanding intravascular stents, a biodegradable poly-D/L-lactic acid (PLA) and a medical stainless steel stent (Wallstent) were implanted in the common iliac arteries of 2 postpuberal female pigs and 3 laboratory-bred beagle dogs. Specimens were harvested after 45 days in the dogs and 32 days in the pigs for histomorphometry of the stented iliac artery segments. Preliminary measurements were made to assess the reliability of the quantitative histomorphometric measurements before final measurements.

RESULTS

Histomorphometry analyses showed that mean luminal diameter and area were decreased in the PLA stent group (1.97+/-0.48 mm and 14+/-6.4 mm2, respectively) compared to the control stent group (4.28+/-0.83 mm and 61+/-19 mm2, respectively). The intimal thickness was higher in the PLA stent group (0.65+/-0.07 mm) than in the control group (0.44+/-0.21 mm). The mean injury score was 0.19+/-0.12 in the PLA stent group and 0.78+/-0.39 in the controls. In the PLA stent group, the mean inflammation score was 1.46+/-0.78 compared to 0.58+/-0.40 in the control group. There were no differences observed between the animal models.

CONCLUSIONS

The PLA stent showed increased neointimal formation and reduced patency during early follow-up. Mechanical properties of the new biodegradable vascular stents are still inadequate, and the stent and the delivery device require modifications. The study methods were assessed as reliable and reproducible.

Requirements for quantitative analysis of intimal reaction in arteries treated with intraluminal stents

PURPOSE

To assess the reliability of quantitative histomorphometry measurements for the intimal reaction that occurs after intraluminal stenting in an animal model.

METHODS

Two self-expanding intravascular stents, a biodegradable poly-D/L-lactic acid (PLA) stent and a stainless steel Wallstent, were implanted in the common iliac arteries of a beagle dog. After 45 days, the histomorphometry of the stented iliac artery segments was quantitatively measured. The relative standard error (RSE) of the estimate was calculated, and the reliability of measurements for maximal (LDmax) and minimal (LDmin) luminal diameters and internal (IELT) and external (EELT) elastic lamina thicknesses was assessed.

RESULTS

The PLA stent required more measurements of variables from a single slide to ensure reliable (RSE<10%) results (1 for LDmax, 1 for LDmin, 8 for IELT, and 4 for EELT) compared to the Wallstent (1 for LDmax, 1 for LDmin, 2 for IELT, and 2 for EELT 2). The measured results were reliable for both stent materials when variables were measured from 2 slides of each segment (proximal/central/distal) of the stent.

CONCLUSIONS

We conclude that these preliminary measurements to estimate the reliability of quantitative histomorphometry measurements should be made and reported before final results are given.