Update management below knee intervention

The application of percutaneous techniques for the treatment of peripheral arterial occlusive disease (PAOD) has gained widespread interest over the last decade. Together with the development of new endovascular tools and with an increasing operator experience, the minimal invasive percutaneous therapy became first line therapy at many institutions. Patients with critical limb ischemia (CLI) due to infrapopliteal lesions are often no good candidates infra-geniculate bypass surgery (IBS), as they often present with prohibitive comorbidities, inadequate conduit, and lack of suitable distal targets for revascularization. Therefore, CLI patients due to blockage of below-the-knee (BTK) arteries are in benefit of the endovascular approach: it offers the advantages of local anesthesia, potentially reduced costs (even anticipating the need for reintervention in many patients), shorter hospital stays The current article provides an overview of the diagnosis and endovascular treatment strategies for infrapopliteal lesions in patients with CLI and gives recommendations for future infrapopliteal device technology advancements.

Present and future of endovascular SFA treatment: stents, stent-grafts, drug coated balloons and drug coated stents

The current evolution towards treating more complex femoropopliteal lesions as seen in the renewed TASC II recommendations clearly reflects the continuous evolutions in femoropopliteal stent design. Recent stent design improvements focus on decreasing stent fractures rates which can negatively impact patency rates. By rearranging strut alignment towards helical connecting bridges or full helical stent designs, stent designers have successfully improved the fracture resistance of their stents. The superior fracture resistance of the latest stent generation in combination with the production of long nitinol stents of up to 20 cm in length allow that more difficult and complex lesions can be treated endovascularly. The continuous perfection of nitinol stent platforms followed by the transfer of coronary technologies (e.g. active coatings) towards peripheral devices might broaden the indications for the minimal invasive strategy towards TransAtlantic Inter-Society Consensus (TASC) II C&D lesions.

[World kidney Day 2008: the impact of epidemiology of kidney diseases in Belgium]

The World Kidney Day offers a crucial opportunity to the Belgian associations of nephrologists to inform public and medical communities about the global problem of chronic kidney disease (CKD). According to epidemiological data from GNFB/ NBVN registries in our country, cardiovascular diseases and diabetes 2 are responsible for an increasing amount of CKD cases with pejorative evolution to end-stage renal disease requiring cost-effective renal replacement therapies (haemodialysis, peritoneal dialysis or renal transplantation). In these patients, the high level of comorbidities and the late referral to the nephrologists are recognized as enhanced morbidity and mortality factors. These facts underline the need for the nephrologists to stimulate collaboration with general practitioners and specialists from other disciplines in order to set up systematic screening procedures and early follow-up of patients at risk of developing CKD. These procedures should contribute to reduce the progression rate of renal function impairment.

Cost-Effectiveness Model of Topical Treatment of Mild to Moderate Psoriasis Vulgaris in Germany

BACKGROUND

Psoriasis vulgaris requires lifelong treatment associated with considerable health cost. Studies showed that a combination of a steroid and a vitamin D(3) analogue is more effective than both compounds in monotherapy.

OBJECTIVE

To determine the cost-effectiveness of a fix calcipotriol/betamethasone combination (Daivobet/Dovobet/Taclonex) compared to a morning/evening non-fix calcipotriol/betamethasone combination in psoriasis treatment.

METHODS

A Markov model (discrete-time stochastic process based on transitions between health states) with 2 treatment arms (Daivobet/Dovobet/Taclonex vs. non-fix calcipotriol/betamethasone) over a 48-week time period was developed. The effectiveness criterion was the number of days with clearance or marked improvement. Clinical and health resource utilisation data were derived from randomised studies.

RESULTS

Treatment with Daivobet/Dovobet/Taclonex showed a higher cost-effectiveness compared to the non-fix combination, even when assuming a maximum compliance for the twice daily non-fix combination and varying the effectiveness of Daivobet/Dovobet/Taclonex by 10%.

CONCLUSION

Psoriasis treatment with a fix calcipotriol/betamethasone combination is more cost-effective than a non-fix morning/evening combination.

Nitinol stenting for treatment of ''below-the-knee'' critical limb ischemia: 1-year angiographic outcome after Xpert stent implantation

AIM

We investigated the efficacy of Xpert (Abbott Vascular Devices) nitinol stents for the treatment of infrapopliteal lesions in patients with critical limb ischemia (CLI).

METHODS

Between May and October 2005, 47 CLI patients (35 men, mean age 73 years) received 67 Xpert stents for the treatment of 58 infrapopliteal lesions in 51 limbs; 43 patients (84.3%) were classified in Rutherford Category 4 and 8 (15.7%) in Category 5. Clinical examination and quantitative vascular analysis (QVA) were performed before and after the intervention and at 12-months follow-up. The primary endpoint was defined as 1-year angiographic binary restenosis rate (>50% stenosis on QVA); the secondary endpoints were 1-year primary patency and limb salvage rate.

RESULTS

QVA after 1 year showed a binary restenosis rate of 20.45%. Kaplan-Meier analysis revealed 1-year primary patency and limb salvage rates of 76.3% and 95.9%, respectively. The limb salvage rate was significantly better in patients with proximal below-the-knee (BTK) than in those with mid-section or distal lesions (100% vs 81.8%; P=0.0071).

CONCLUSION

Our results suggest that treatment with nitinol Xpert stents in CLI patients is effective and yields satisfactory angiographic and clinical outcome.

Are there predictive risk factors for complications after carotid artery stenting?

AIM

The aim of this study was to identify predictive risk factors for complications during and after carotid artery stenting (CAS).

METHODS

A multivariate analysis was performed on the databases of 4 European high-volume centers regarding risk factor distribution between patients presenting with or without neurological complications 30 days after CAS. The cumulative 30-day neurological complication rate (death, major stroke, minor stroke and transient ischemic attack) was 2.8% in the total examined cohort of 3 179 consecutive CAS procedures. The following risk factors were taken into consideration for statistical analysis: age, symptomatic, male gender, nicotine abuse, hypertension, hypercholesterolemia, polyvascular disease, diabetes, restenosis after carotid endarterectomy (CEA)/CAS, calcified internal carotid artery.

RESULTS

Symptomatic (P=0.02) or hypercholesterolemic (P=0.02) patients are at significantly increased risk for neurological events 30 days after CAS. Asymptomatic women and men without hypercholesterolemia have the lowest risk on any 30-day neurological complications after CAS.

CONCLUSIONS

CAS is a safe technique in experienced hands. Preprocedural neurological complaints and hypercholesterolemia can be defined as predisposing factors for 30-day neurological complications after CAS.

Does Free Cell Area Influence the Outcome in Carotid Artery Stenting?

OBJECTIVES

To identify if carotid stent design, especially free cell area, impacts on the 30-day rates for stroke, death and TIA after carotid artery stenting (CAS).

MATERIAL AND METHODS

A CAS database of 3179 consecutive CAS patients was retrospectively assessed. The distribution of neurological complications were analysed for association with the different stent types and designs. Events where subdivided into procedural and postprocedural events.

RESULTS

The overall combined rate of TIA, stroke and death was 2.8% at 30 days (late events 1.9%). The post-procedural event rate analyzed for differences stents varied from 1.2% using BSCI Carotid Wallstent to 5.9% using Medtronic Exponent. The late event rates varied from 1.2% to 3.4% for free cell areas <2.5mm(2) and >7.5mm(2) respectively (p<0.05). Post-procedural event rate was 1.3% for closed cells and 3.4% for open cells. All these differences were highly pronounced among symptomatic patients (p<0.0001).

CONCLUSIONS

After carotid stenting, complication rates vary according to stent type, free cell area and cell design. In the symptomatic population (and also in the total population), post-procedural complication rates are highest for the open cell types and increase with larger free cell area.

Flemish experience using the Advanta V12 stent-graft for the treatment of iliac artery occlusive disease

AIM

The aim of this study was to evaluate the technical feasibility and safety of implanting a polytetrafluoroethylene (PTFE) covered balloon expandable stent to treat iliac artery stenoses and occlusions. Additionally, the primary patency and clinical and hemodynamic efficacy at 1 year were analysed.

METHODS

This nonrandomized, prospective study involved patients with claudication and iliac artery occlusive disease at 2 participating centres. Patients with suitable lesions determined by clinical examination, ankle-brachial indices (ABIs), colour-flow duplex ultrasound (CFDU), magnetic resonance angiogram (MRA) and confirmed with biplanar digital subtraction angiography (DSA) were treated with PTFE-covered stainless steel stents. Procedural and 30-day periprocedural complications were recorded prospectively. According to in-hospital standards, follow-up with clinical ischemia category determination, ABI and CFDU was performed at 1, 6 and 12 months to determine treatment efficacy and primary limb patency.

RESULTS

In total, 91 limbs were treated in 65 patients (51 male; mean age 65 years). Stent-graft deployment was successful in 91 (100%) limbs. There were no limbs with residual stenosis >30%. There were no procedural or 30-day complications. The clinical ischemia category distribution improved significantly at 1, 6 and 12 months. The mean ABI rose significantly from 0.59 before treatment to 0.98, 0.98 and 0.99 at 1, 6 and 12 months after the procedure. Primary limb patency at 1-year was 91.1%

CONCLUSIONS

Implantation of Advanta V12 PTFE-covered stent for iliac occlusive disease shows to be safe and feasible with excellent clinical results at 1 year in the investigated patient cohort.

Validation of 16S rDNA sequencing in microdissected bowel biopsies from Crohn's disease patients to assess bacterial flora diversity

The bowel flora is implicated in Crohn's disease (CD) pathogenesis but its precise role is still unclear. Several non-mutually exclusive hypotheses have been proposed: an unidentified persistent pathogen; excessive bacterial translocation; an immune system abnormality in response to normal bacteria; or a breakdown in the balance between protective and harmful bacteria. These hypotheses can be tested by identifying bacteria in specific microscopic bowel structures or lesions. The present paper describes a novel technique to assess bacterial flora diversity in bowel biopsies, by combining laser capture microdissection with broad-range 16S rDNA sequencing. Fifty-four samples comprising histologically normal and pathological mucosa, MALT, ulcers, submucosal lymphangiectasias, epithelioid granulomas, and lymph nodes were microdissected out of 30 bowel biopsies from five CD patients. Bacterial 16S rDNA was successfully amplified by PCR in all samples, and PCR products from 15 samples were selected for cloning and sequence analysis. A total of 729 bacterial DNA sequences were analysed, which could be attributed to six different phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Fusobacteria, and Planctomycetes). DNA from typical bowel bacteria (Enterobacteriaceae, Clostridiales, Bacteroidetes, Fusobacteria) was detected in all microdissected areas. It was thus convincingly demonstrated that 16S rDNA sequencing can be combined with microdissection to study the bowel flora. However, no specific persistent pathogen causal for CD was identified. The results suggest that Enterobacteriaceae may initiate or colonize ulcers in CD. Translocation of bacteria through established mucosal lesions or as a result of increased permeability may be involved in the evolution towards chronic inflammation and in the establishment of persistent lesions. Further study is needed to confirm these preliminary findings.

Results with heparin bonded polytetrafluoroethylene grafts for femorodistal bypasses

AIM

Expanded polytetrafluoroethylene (ePTFE) grafts are commonly used for femoropopliteal (FP) and femorocrural (FC) bypass grafting. Especially in below-knee (BK) reconstructions, patency is often inferior to the outcome in patients eligible for venous bypass grafting. This study assesses whether the Carmeda BioActive Surface (CBAS), which employs covalent end-point linkage to retain heparin on the device surface, as it is used on the Propaten vascular graft successfully, can prolong patency.

METHODS

From June 2002 to December 2005, 138 patients (97 men and 41 women; mean age: 73 years) received the CBAS-ePTFE graft for 153 infrainguinal bypass procedures. Seventy-five above-knee (AK) and 78 BK (including 37 FC) procedures were performed. Follow-up evaluations consisted of clinical examinations, ultrasonographic studies, and distal pulse assessments. Patency and limb salvage rates were assessed by using life-table analyses.

RESULTS

The overall primary and secondary 2-year patency rates were 73.6% and 86%, respectively. Two-year primary patency rates according to bypass type were 76.2%, 72.6%, and 68.9% for AK FP, BK FP, and FC bypasses, respectively; the corresponding secondary patency rates were 87.5%, 87.8%, and 79.4%. The 2-year limb salvage rate in patients with critical limb ischemia (n=68) was 89.9%.

CONCLUSION

Our findings show that CBAS-ePTFE bypass grafts appear to give prolonged patency rates and indicate that the use of this graft may represent a viable alternative for BK bypasses, which have traditionally yielded less than desirable outcomes. A prospective randomized trial is required to provide more definitive information about the graft's patency and limb salvage performance.

Will absorbable metal stent technology change our practice?

Peripheral stents aim to support revascularization procedures of intravascular stenoses by mechanically preventing vessel recoil and counteracting pathophysiologic processes of luminal re-narrowing triggered by procedural injury of the vessel wall. Despite improvements in stenting techniques and concomitant medication, repeated intervention due to target lesion re-stenosis is necessary on a significant percentage of patients. The permanent presence of an artificial implant plays a prominent role in the discussion of mechanisms causing in-stent restenosis. Permanent metallic implants pose the risk of a continuous interaction between non-absorbable stent and surrounding tissue, leading to physical irritation, long-term endothelial dysfunction, or chronic inflammatory reactions. In addition, there is a risk of stent fracture due to external mechanical forces. To overcome these shortcomings, technology of stenting has moved towards the development of temporary implants composed of biocompatible materials which mechanically support the vessel during the period of high risk for recoil and then completely degrade in the long-term perspective. This removes a potential trigger for late restenosis.

Balloon-expandable, radially reinforced ePTFE relining of the superficial femoral artery after remote endarterectomy

AIM

The aim of this paper was to evaluate the mid-term results of remote endarterectomy and balloon-expandable, radially reinforced ePTFE endograft uplining of the superficial femoral artery (SFA) for long occlusions.

METHODS

One hundred and two limbs in 92 patients were included in this prospective, multicenter study. Indications were disabling claudication (n=74), restpain (n=10) and tissue loss (n=16) due to an SFA occlusion of at least 10 cm in length. Remote endarterectomy of the SFA using a modified ringcutter in an over-the-wire technique, was followed by implantation of a balloon-expandable Enduring endovascular graft. Control visits were performed at 1, 3 and 6 months postprocedure and every half year from then on. Follow-up protocol included physical examination, Doppler ankle-brachial index measurement and, in case of doubt, duplex examination.

RESULTS

A technical success rate of 98% was achieved. Mean follow-up was 36 months. Four patients were lost to follow-up and 17 patients died of nondevice-related causes. The primary, primary assisted and secondary patency rates were 68%, 73% and 97.5% at 1 year and 50%, 60%, and 89% at 3 years, respectively.

CONCLUSION

Although technical success rate is high and early patency rates are good, mid-term results are inferior to those of conventional femoro-popliteal synthetic bypass grafts. In order to become competitive to conventional bypass surgery, further technical refinements will be necessary, especially to overcome the problem of stenoses at the distal transition zone.

Severe diarrhea in renal transplant patients: results of the DIDACT study

Diarrhea is common in transplant recipients. While the majority of cases are mild and transient, some are severe and prolonged, which can threaten graft survival through dehydration. While it is known that some immunosuppressive agents can elicit diarrhea, there does not appear to be any consensus on the role that other nonimmunosuppressive causes can play in transplant patients. The aim of the present open, nonrandomized, multicenter study was to identify nonimmunosuppressive factors involved in severe diarrhea in renal transplant patients. Patients (n = 108) with severe diarrhea (>/=3 stools/day for >/=7 days) were enrolled from 16 Belgian transplant centers. Patients were diagnosed according to an agreed flowchart that consisted of identification of possible infections, followed by changes in empirical and immunosuppressive treatment. Approximately 50% of patients experienced resolution of severe diarrhea following treatment for infections, dietary problems or diarrhea-causing concomitant medications. In conclusion, a large proportion of the severe diarrhea observed in renal transplant recipients is not associated with immunosuppressive therapy and can be treated through anti-infectives, changes to concomitant medication and other empirical treatments. Correct diagnosis of the cause of severe diarrhea in such patients should help to protect graft survival in transplant recipients.

Percutaneous transluminal angioplasty for treatment of ''below-the-knee'' critical limb ischemia: early outcomes following the use of sirolimus-eluting stents

AIM

We investigated the safety and efficacy of sirolimus-eluting stents in the treatment of patients with severe below-the-knee' critical limb ischemia.

METHODS

Between October 2004 and January 2005 we performed 20 percutaneous transluminal angioplasty procedures on 18 patients (7 female, 11 male, mean age 72.8 years), implanting 24 sirolimus-eluting stents. At pre-procedure, 12 patients (66.7%) presented with a Rutherford Category 4, 4 (22.2%) with Category 5 and 2 (11.1%) with Category 6. The majority of patients (72.2%, n=13) were non-smokers and 77.8% (n=14) presented with hypercholesterolemia. Calcification was present in 52.2% (n=12) of lesions. Pre-dilation was performed in half the patients. The majority of lesions (95.7%, n=22) were treated with a single sirolimus-eluting stent. Two patients underwent 2 procedures, each one receiving 2 sirolimus-eluting stents. Clinical examination and quantitative vascular analysis were performed in all patients at discharge and at 6-month follow-up.

RESULTS

Percutaneous transluminal angioplasty was successfully performed on all 18 patients. The mean stent length and stent diameter were 30.29 mm and 3.23 mm, respectively. Mean follow-up was 256 days (170-368 days). At the 6-month follow-up, the minimum lumen diameter as measured by Quantitative Vessel Analysis was 2.39 mm with an attendant LLS of 0.38 mm. The overall 6-month survival and limb salvage rate were 94.4% and 94%, respectively.

CONCLUSIONS

Our results suggest that treatment with sirolimus-eluting stents can be considered as an effective and safe treatment of patients with critical ischemia.

Review of stents for the carotid artery

The individual characteristics of a stent may make it an attractive choice in some circumstances, but render it a less desirable option in others. The applicability depends primarily on the arterial anatomy and the specific details of the lesion being treated. A careful assessment by the interventionalist is required to select the proper type of stent that is of appropriate size. Certainly, personal preferences and familiarity with a specific device may legitimately influence the decision to choose one stent over another. Finally, stent design can play a role in the selection procedure. Although carotid stents are often functionally equivalent in the clinical setting and have been used successfully to treat a wide variety of lesions, a basic knowledge of stent geometry can contribute to make up your mind in certain carotid cases.

Complex thoracic aortic aneurysm: a combined open and endovascular approach

The authors wish to describe a combined open and endovascular approach to repair a complex thoracic aortic aneurysm. A 72-year-old man with chronic obstructive pulmonary disease, aortic valvular insufficiency and diffuse thoracic aortic aneurysm underwent aortic valve and ascending aorta replacement by a Bentall-procedure and replacement of arch aneurysm using the elephant trunk technique, performed in a first procedure. During the second procedure, endovascular stenting of the descending thoracic aorta was done. Only a few similar case reports have been presented. Endovascular repair after an elephant trunk procedure for complex thoracic aortic aneurysms is an elegant approach to deal with such mega aortas. Further research is necessary to compare open and endovascular repair and to determine long-term follow-up with regard to endoleaks and mortality.

Does carotid artery stenting work on the long run: 5-year results in high-volume centers (ELOCAS Registry)

AIM

Although the first long-term results of Carotid Artery Stenting (CAS) became available only recently, CAS has become an accepted treatment for carotid artery disease. We report CAS data up to 5 years, both late stroke rate and patency rates as observed in 4 high-volume European centers.

METHODS

Between February 1, 1993 and December 31, 2004, 2 172 patients were selected over the 4 participating centres, with intention to treat endovascularly. Conscientious follow-up was done according to the in-hospital stipulations of each centre and was entered into a database both retrospectively and prospectively. Long-term restenosis and stroke-death rates were investigated and statistically analysed and stratified using the Kaplan-Meier method.

RESULTS

Of the 2 172 patients with intention to treat 2 165 (99.7%) were technically successful. Of these 306 (14.1%) were performed without and 1 859 (85.9%) with embolic protection device (EPD); 96 patients (4.4%) received balloon dilation only and stenting was performed in 2 069 (95.6%) cases. Kaplan-Meier analysis of major stroke/all death and of significant restenosis (>50%) for the total population showed stroke/death rates of 4.1% (nar=1 356), 10.1% (nar=476) and 15.5% (nar=138); and restenosis rates of 1% (nar=1 363), 2% (nar=480) and 3.4% (nar=139), after 1, 3 and 5 years respectively.

CONCLUSIONS

The patency and stroke/death rates resulting from our database analysis are pleasing and indicate that CAS also on longer term is a valuable treatment method for carotid artery disease. Due to the fact that our dataset contains prospective as well as retrospective data, it may have its limitations. Until this moment, data indicating that certain patient subgroups are at increased risk for neurological complications and in-stent restenosis during and after CAS are sparse. Further multivariant analysis on this unique dataset is mandatory in order to identify any potential links in between plaque morphology, preprocedural neurological complications, risk factor distribution, procedural steps and clinical outcome.