Comparison of Open and Endovascular Aneurysm Repair in Native Arteriovenous Fistulas

BACKGROUND

Arteriovenous accesses develop aneurysms (FA) during their active use, resulting in pain, erosion, bleeding, and difficulty in cannulation. This study aims to evaluate the outcomes of open and endovascular management of single FA in arteriovenous fistulas (AVF).

METHODS

A retrospective review of all upper extremity primary AVFs over 12 years was undertaken at a single center. Patients undergoing elective open and endovascular repair of a single FA were identified. Thirty-day outcomes, cannulation failure, line placement, re-intervention, and functional dialysis (continuous hemodialysis) for 3 consecutive months were examined.

RESULTS

Three hundred and seventy nine patients presented with a single FA that met the requirements for intervention: 126 (33%) underwent endovascular repair, and the remainder 253 (67%) underwent open repair. Preoperative fistulogram identified anatomically significant issues in 91% of the cases, and these were treated by balloon angioplasty: 10% within the fistula tract, 44% within the outflow tract, and 47% in the central veins. In open repair, 57% underwent plication, 35% underwent resection and re-anastomosis, and the remainder (8%) underwent interposition grafting. In endovascular repair, successful placement of a stent was achieved in all cases with 1 ± 2 (mean ± standard deviation [SD]) covered stents (diameter: 6 -8 mm) placed, achieving successful exclusion of the FA. The combination of early thrombosis and cannulation failures led to the greater need for a tunneled central line in endovascular repair (6.5% vs. 2.4%; endovascular versus open repair; P = 0.04). As a result, the mean time for establishing renewed access in the index AVF was significantly higher in endovascular repair (2 ± 3 vs. 2 ± 2 weeks, mean ± SD; endovascular open repair versus open repair; P = 0.001). In follow-up, there were more secondary interventions per year in the endovascular compared to open repair groups (3.1 vs. 1.4 secondary interventions per year; endovascular versus open repair; P = 0.04). Median functional dialysis durations were superior in the open repair (48 ± 6%, mean + standard error) compared to the endovascular repair at 5 years. (26 ± 7%; P = 0.03).

CONCLUSIONS

Open repair results in a more rapid return to access use, lower need for a tunneled central line, lower secondary re-intervention rates, and superior functional dialysis durations compared to endovascular repair. Open FA repair should be considered for symptomatic single FA repairs before endovascular FA repair.

Functioning tailor-made 3D-printed vascular graft for hemodialysis

BACKGROUND

The two ends of arteriovenous graft (AVG) are anastomosed to the upper limb vessels by surgery for hemodialysis therapy. However, the size of upper limb vessels varies to a large extent among different individuals.

METHODS

According to the shape and size of neck vessels quantified from the preoperative computed tomography angiographic scan, the ethylene-vinyl acetate (EVA)-based AVG was produced in H-shape by the three-dimensional (3D) printer and then sterilized. This study investigated the function of this novel 3D-printed AVG in vitro and in vivo.

RESULTS

This 3D-printed AVG can be implanted in the rabbit's common carotid artery and common jugular vein with ease and functions in vivo. The surgical procedure was quick, and no suture was required. The blood loss was minimal, and no hematoma was noted at least 1 week after the surgery. The blood flow velocity within the implanted AVG was 14.9 ± 3.7 cm/s. Additionally, the in vitro characterization experiments demonstrated that this EVA-based biomaterial is biocompatible and possesses a superior recovery property than ePTFE after hemodialysis needle cannulation.

CONCLUSIONS

Through the 3D printing technology, the EVA-based AVG can be tailor-made to fit the specific vessel size. This kind of 3D-printed AVG is functioning in vivo, and our results realize personalized vascular implants. Further large-animal studies are warranted to examine the long-term patency.

Direct puncture versus contralateral femoral artery approach for catheter-directed thrombolysis of occluded infra-inguinal arterial bypass grafts

AIM

To compare the safety, effectiveness, and clinical outcome of percutaneous direct puncture approach versus contralateral femoral native vessel approach for catheter-directed thrombolysis of occluded infra-inguinal bypass grafts.

MATERIALS AND METHODS

A retrospective analysis was performed comprising a cohort of patients who underwent catheter-directed thrombolysis procedures of occluded infra-inguinal bypass grafts between January 2013 and January 2022, with a follow-up period until June 2022. This included 55 procedures via the native vessel approach and 18 procedures via the direct puncture approach. Primary outcomes were technical success and procedural safety; secondary outcomes included re-intervention rate, limb salvage, and mortality as assessed by log-rank testing and Kaplan-Meier curves.

RESULTS

There were no differences between the two groups with regard to patient demographics, except for the number of previous vascular procedures (n=6.83 ± 3.07 direct approach versus n=4.96 ± 2.79 native vessel approach, p=0.025). Thrombolysis was comparably successful in both groups (n=13/18; 72% direct approach versus n=42/55; 76%, p=0.723). There were no differences in the duration of thrombolysis administration. The rate of adverse events was slightly lower in the direct approach group, but without significance (p=0.092). There were no adverse events related to the puncture site in the direct approach group. No differences were found between the time-to-event values for re-occlusion, re-intervention, amputation, or mortality respectively (p=0.662; p=0.520; p=0.816; p=0.462).

CONCLUSION

The direct puncture approach seems to be a safe and efficient approach for catheter-directed thrombolysis procedures in infra-inguinal occluded bypass grafts, with clinical outcomes comparable to the native vessel approach.

The reasons for comparative effectiveness clinical trials of arteriovenous fistula versus graft strategy in older adults on hemodialysis with a catheter

Clinicians and patients are guided by observational studies to make one of the most consequential decisions for patients with advanced kidney disease: the selection of the "right" hemodialysis vascular access. More than a decade ago, a call for randomized clinical trials was made to equitably compare clinical outcomes between arteriovenous (AV) fistulas (AVFs) and AV grafts (AVGs). Mounting evidence suggests that trade-offs between AVF- and AVGrelated outcomes are context dependent. In this article, we summarize four streams of evidence that collectively underpin the burden of equipoise between the two types of AV access in older adults with comorbidities who are on hemodialysis with a central venous catheter.

The Use of Viatorr Stent at the Thoracic Outlet to Maintain Hemodialysis Access Function

PURPOSE

Venous steno-occlusive disease at the thoracic outlet affects up to 30% of the hemodialysis population [1] causing arm swelling and hemodialysis access dysfunction. Balloon angioplasty in this region can be of limited utility given the rigid compressive effect of surrounding musculoskeletal (MSK) structures. Outcomes of using the Viatorr endoprosthesis (Gore Viatorr TIPS Endoprosthesis, Gore, Flagstaff AR, USA, Viatorr ®) within this region to salvage the HD access in patients who presented with dialysis access dysfunction is presented.

METHODS

A retrospective chart review was performed of our tertiary and quaternary care hospital system. Hemodialysis patients were included in the study if they were using an upper extremity arteriovenous fistula or graft for access, had a Viatorr stent placed in the central (subclavian and/or brachiocephalic) veins, and had follow up.

RESULTS

A total of nine patients were identified to meet the inclusion criteria. Four interventions were due to refractory lesions of the subclavian or brachiocephalic veins, and the other five interventions were for hemodynamically significant lesions refractory to angioplasty alone, all resulting in access dysfunction. Primary patency ranged from 36-442 days (geometric mean 156.6 days, range 19-442 days). No stent fracture was identified on imaging at any point during follow-up of these patients out to a maximum of 2912 days (Average 837 days).

CONCLUSIONS

The Viatorr stent graft used in the HD population for clinically significant lesions at the thoracic outlet (TO) showed no structural failures (fractures) in this cohort.

Comparison of puncture methods in patients with hemodialysis: A randomized controlled trial

INTRODUCTION

Arteriovenous fistula or arteriovenous graft is essential to long-term survival and quality of life in patients receiving hemodialysis. To date, no research has examined the clinical impacts of different puncture methods. This study compared the rope ladder and area puncture techniques in terms of vascular patency, pain, and quality of life among patients receiving hemodialysis.

METHODS

A prospective longitudinal study was performed with 6-month follow-up. A total of 98 participants recruited from a hemodialysis center in Taiwan were randomly assigned to receive the rope ladder technique (experimental group) or the area puncture technique (control group). Vascular patency was assessed by examining access flow and percutaneous transluminal angioplasty rate. Pain and quality of life were measured using the Numerical Pain Rating Scale (NPRS) and Kidney Disease Quality of Life Instrument (KDQOL-36™), respectively. All outcome variables were measured repeatedly and analyzed using a generalized estimating equation.

RESULTS

Overall, quality of life was significantly better for the experimental group than for the control group (β = 47.23, p < 0.001). The percutaneous transluminal angioplasty rate was lower for the experimental group than for the control group (12.0% vs. 18.8%). However, no significant differences were found in access flow and pain level between the two groups over time.

CONCLUSION

Hemodialysis patients who received the rope ladder puncture technique had a lower percutaneous angioplasty rate and better quality of life than patients who received the area puncture technique, suggesting that the rope ladder technique could be implemented as a routine cannulation method in hemodialysis clinics.

Functional Impairment is Associated with Poor Long-Term Outcomes after Arteriovenous Access Creation

BACKGROUND

Functional impairment affects outcomes after a variety of procedures. However, the impact of functional impairment on outcomes of arteriovenous (AV) access creation is unclear. We aimed to evaluate the association of patients' ability to ambulate and perform activities of daily living (ADL) with AV access outcomes.

METHODS

We retrospectively reviewed patients undergoing AV access creation at an urban, safety-net hospital from 2014 to 2022. We evaluated associations of impaired ambulatory and assisted ADL status with 90-day readmission, 1-year primary patency, and 5-year mortality.

RESULTS

Among the 689 patients receiving AV access, mean age was 59.6 ± 13.9 years, 59% were male, and 60% were Black. Access types included brachiocephalic (42%), brachiobasilic (26%), radiocephalic (14%), other autogenous (5%) fistulas, and prosthetic grafts (13%). Impaired ambulatory status was identified in 35% and assisted ADL status, when assessed, was identified in 21% of patients. Ninety-day readmission was more likely in patients with impaired ambulatory (58% vs. 39%, P < 0.001) and assisted ADL (56% vs. 41%, P = 0.004) status. On Kaplan-Meier analysis, 1-year primary patency was lower for patients with impaired ambulatory status (44% ± 3% vs. 29% ± 3%, P = 0.001), but was not significantly different for patients with assisted ADL status (41% ± 3% vs. 32% ± 5%, P = 0.12). Five-year survival was lower for patients with impaired ambulatory status (53% ± 5% vs. 74% ± 4%, P < 0.001), but was not significantly different for patients with assisted ADL status (45% ± 9% vs. 71% ± 4%, P = 0.1). On multivariable analysis, increased likelihood of 90-day readmission was significantly associated with impaired ambulatory status (odds ratio (OR) 2.03, 95% confidence interval (CI) 1.4-2.94, P < 0.001) and assisted ADL status (OR 1.66, 95% CI 1.07-2.57, P = 0.02). One-year primary patency was not significantly associated with impaired ambulatory (hazard ratio (HR) 1.25, 95% CI 0.98-1.6, P = 0.07) or assisted ADL status (HR 1.13, 95% CI 0.87-1.48, P = 0.36). Increased likelihood of 5-year mortality was associated with impaired ambulatory (HR 1.65, 95% CI 1.04-2.62, P = 0.04) and assisted ADL status (HR 2.63, 95% CI 1.35-5.11, P = 0.004).

CONCLUSIONS

Impaired ambulatory and assisted ADL statuses were associated with increased readmissions and long-term mortality after AV access creation. Approximately half of patients with functional impairment were not alive at 5 years. Setting outcome expectations as well as prospectively examining the impact of physical therapy and visiting nursing services for functionally impaired patients undergoing AV access creation are warranted.

Cephalic arch stenosis in the arteriovenous fistula: A retrospective analysis of predisposing factors

BACKGROUND

Cephalic Arch Stenosis (CAS) is a frequently observed complication in brachiocephalic and radiocephalic arteriovenous fistulae (AVF) associated with high morbidity and healthcare expenditure. The predisposing factors and preventative strategies for CAS remain unclear. Our aim was to examine predisposing factors for CAS development in the AVF.

METHODS

A retrospective case-control study was performed at Gold University Coast Hospital on patients with AVFs created from 2009 to 2018 with ⩾18 months follow-up. CAS was defined as a >50% narrowing on angiographic assessment with clinically significant symptoms (dialysis dysfunction, arm swelling, prolonged bleeding after access).

RESULTS

About 187 patients with AVF were included in the analysis (36 brachiocephalic, 151 radiocephalic). CAS developed in 22 of 36 (61%) of brachiocephalic AVF and 9 of 151 (6%) of radiocephalic AVFs. Brachiocephalic AVF were ⩾12 times more likely to develop CAS than radiocephalic AVF (Hazard Ratio (HR) 12.7, 95% CI [5.6-28.3], p < 0.001). Each 1 mL/min increase in flow rate through the AVF, correlated with a 0.07% increase in the probability of development of CAS (HR 1.0007, 95% CI [1.0001-1.0012], p = 0.011). Brachiocephalic AVFs with CAS were associated with a higher number of interventional procedures per access-year compared with their non-CAS counterparts (Median [Interquartile range]: 1.76 [0.74, 3.97] vs 0.41 [0.27, 0.67], p = 0.003).

CONCLUSION

Brachiocephalic AVF with higher access flow rates are more likely to develop CAS and earlier than radiocephalic AVF, and in a dose dependent fashion. AVF flow rate is a major factor in CAS development within brachiocephalic AVF and has potential utility in surveillance thresholds for prophylactic blood flow reduction procedures. AVFs with CAS are associated with a greater number of interventional procedures per access-year, heralding higher patient morbidity and healthcare expenditure. Further prospective studies will help define an AVF access flow rate threshold in the implementation of prophylactic strategies for CAS.

The role of venous pressure variability during hemodialysis in the prediction of impending arteriovenous graft occlusion

BACKGROUND

Elevated venous pressure during hemodialysis (VPHD) is associated with arteriovenous graft (AVG) stenosis. This study investigated the role of VPHD variations in the prediction of impending AVG occlusion.

METHODS

Data were retrieved from 118 operations to treat AVG occlusion (occlusion group) and 149 operations to treat significant AVG stenosis (stenosis group). In addition to analyzing the VPHD values for the three hemodialysis (HD) sessions prior to the intervention, VPHD values were normalized to mean blood pressure (MBP), blood flow rate (BFR), BFR × MBP, and BFR2 × MBP to yield ratios for analysis. The coefficient of variation (CV) was used to measure relative variations.

RESULTS

The within-group comparisons for both groups revealed no significant differences in the VPHD mean and CV values among the three HD sessions prior to intervention. However, the CVs for VPHD/MBP, VPHD/(BFR × MBP), and VPHD/(BFR2 × MBP) exhibited significant elevation in the occlusion group during the last HD session prior to intervention compared with both the penultimate and antepenultimate within-group HD data (p < 0.05). In the receiver operating characteristic curve analysis, the CV for VPHD/(BFR2 × MBP) was the only parameter able to discriminate between the last and the penultimate HD outcomes (p < 0.001). According to a multivariate analysis, after controlling for covariates, CV for VPHD/(BFR2 × MBP) >8.76% was associated with a higher risk of AVG thrombosis (odds ratio: 3.17, p < 0.001).

CONCLUSIONS

Increasing the variation in VPHD/(BFR2 × MBP) may increase the probability of AVG occlusion.

Sedoanalgesia with intravenous midazolam and fentanyl for angioplasty of dysfunctional arteriovenous access: A retrospective single-center analysis

BACKGROUND

Endovascular therapy, such as percutaneous transluminal angioplasty (PTA), stenting, or embolization, is a well-established form of treatment to prolong the lifespan of arteriovenous access. These procedures, especially PTA, can be accompanied with severe pain. We reviewed and analyzed the efficacy, safety, and outcome of sedoanalgesia using intravenous midazolam and fentanyl, for pain relief during these procedures.

METHODS

Two hundred and two consecutive patients with dysfunctional dialysis access that had undergone endovascular procedure in our institute between July and November 2017 were included in this study. The dialysis access profile, procedure complication, and 10-point Visual Analog Scale (VAS) were collected. One-year clinical follow-up record was also collected to evaluate arteriovenous access patency and long-term complications.

RESULTS

Among the 202 patients, the mean age was (mean ± SD) 67.0 ± 12.08 years. Dialysis access profile of these patients were 119 (58.9%) native arteriovenous fistula and 162 (74.2%) forearm access. The number of lesions treated were 1.63 ± 0.802.Immediate complications included 11 (5.44%) nausea/vomiting, 24 (11.88%) desaturation (SpO2 < 90%, resolved after pillow removal or jaw trust), 16 (7.9%) hypotension (SBP < 90 mmHg, resolved without inotropic agents). There was a low average pain score (1.16 ± 1.594) during the procedure with 136 (67.3%) no pain (VAS 0-1) and 56 (27.7%) mild pain (VAS 2-4). Higher VAS score correlated with overweight patients, longer PTA time and pain after procedure. Six-month primary patency rate was 49.17% and primary assisted patency rate was 93.04%.

CONCLUSIONS

Sedoanalgesia with intravenous midazolam and fentanyl is an easy, safe, and effective method for surgeons.

[Cephalic arch stenosis. Case report and literary review]

Dysfunctional AVF represents one of the leading causes of morbidity in the hemodialysis population, with venous stenosis-related dysfunction being the most common underlying problem. Cephalic arch is a well-known site for the development of stenosis, especially in patients with brachiocephalic fistulas. The pathophysiology of cephalic arch stenosis (CAS) is still being investigated and various contributing factors have been suggested. The treatment options for CAS are many and include angioplasty, endovascular stent insertion, access flow reduction and surgical interventions, but none of the current modalities are ideal. Therefore, the treatment of CAS is difficult, as the stenosis in this area tends to recur leading to the need for repeat angioplasty, stents or surgical revision. A 57-year-old woman undergoing hemodialysis (HD) through a right brachiocephalic arteriovenous fistula was found to have high venous pressure during HD and prolonged bleeding after HD. Clinical examination revealed a hyperpulsatile fistula suggestive of outflow obstruction. Doppler ultrasound examination showed cephalic vein thrombosis, severe outflow stenosis and juxta-anastomotic area. A 10 x 40 mm stent (Cordis Smart stent) was positioned appropriately in the cephalic arch and deployed, the stenotic lesion in juxta-anastomotic area was dilated with angioplasty balloon with improvement in flow. After 14 months, the fistula is still working perfectly with adequate flow.

A UK Expert Consensus Approach for Managing Symptomatic Arteriovenous Fistula (AVF) Stenosis in Haemodialysis Patients

PURPOSE

Stenoses in mature arteriovenous fistulas (AVFs) are common and can negatively impact on the quality of haemodialysis, the longevity of the AVF and lead to debilitating symptoms. Multiple treatment options exist; however, management can vary between different centres. We aimed to establish multidisciplinary consensus on the optimal stepwise application of interventions based on evidence and consensus.

METHODS

A modified Delphi process was conducted with 13 participants from hospitals across the UK, all of whom have high-volume dialysis access practice.

RESULTS

The usual intervention to rectify de novo stenoses of mature AVFs is fistuloplasty, although surgery for inflow segment stenoses is also clinically acceptable. Appropriate first-line interventions include plain old balloon angioplasty or high-pressure balloon angioplasty; if these fail during the fistuloplasty, consider upsizing the balloon, prolonged balloon inflation or using alternative interventions, such as cutting or scoring balloons and ultra-high-pressure balloons. Alternative or subsequent interventions vary by anatomical site and may require additional multidisciplinary team input. For a stenoses recurring between 3 and 12 months, it is appropriate to consider interventions used de novo, but with a lower threshold for using drug-coated balloons (DCBs) in all regions and for using stent grafts in all regions but inflow segment. Recurrence after 12 months should be treated as a de novo lesion, with DCBs considered if they have been used successfully during previous interventions.

CONCLUSIONS

These recommendations aim to provide a practical guide to multidisciplinary teams in order to optimise the use of multiple interventions for rectifying AVF stenoses and provide unified evidence-based practice guidelines.

Endovascular treatment of symptomatic intracranial atherosclerotic stenosis with low profile visualized intraluminal support stent

OBJECTIVE

Severe intracranial atherosclerotic stenosis has become one of the main causes resulting transient ischemic attack and stroke. This study aimed to evaluate the efficacy and safety of low profile visualized intraluminal support (LVIS) stent in treating symptomatic intracranial atherosclerotic stenosis.

METHODS

Data of 31 patients with at least 70% stenosis treated with LVIS stent in our center were retrospectively collected between July 2017 and November 2020. Further evaluation of lesion characteristics, technical success rate, preoperative complication, clinical and angiographic follow-up outcome, delayed in-stent stenosis were conducted.

RESULTS

Stent delivery and deployment were successfully achieved in all 31 patients (100%). 22 cases (71%) were located in anterior circulation and 9 cases (29%) were located in posterior circulation. The mean degree of stenosis lesion before stent deployment was 85.6 ± 9.4%, while after stenting was 11.2 ± 11.8%. One patient suffered from ischemic complication in stenting procedure, and timely delivery of rt-PA successfully recanalized the artery. Clinical follow-up was available in all 31patients (100%) with mean follow-up time 15.0 ± 12.1(3-45) months. No patients experienced the recurrence of stroke or TIA or death after discharge. Angiographic follow-up was available in 21patients (67.7%) with mean follow-up time 11.43 ± 6.8 (6-36) months. 19 patients (90.5%) were stable while 2 patients (9.5%) developed ISR in their last angiographic follow-up. The 2 patients received balloon angioplasty and reached satisfactory results after retreatment.

CONCLUSION

This preliminary study suggests that LVIS stent deployment was a feasible approach in treating intracranial atherosclerotic stenosis with satisfactory procedure success rate, low complication rate and favorable long-term outcome.

Covered stents versus balloon angioplasty for failure of arteriovenous access: a systematic review and meta-analysis

INTRODUCTION

Patients with end-stage renal disease may require arteriovenous (AV) access in the form of arteriovenous fistulae (AVFs) or arteriovenous grafts (AVGs) for haemodialysis. AV access dysfunction requires intervention such as plain balloon angioplasty or covered stents to regain patency.

AIM

To systematically review and meta-analyse the patency outcomes of covered stents in failing haemodialysis AV access, compared with balloon angioplasty.

METHODS

The review was first registered on the International Prospective Register of Systematic Reviews (CRD42018069955) before data collection. We searched six electronic databases to identify relevant randomised controlled trials (RCTs) up until August 2020, without language restriction. Two reviewers assessed the suitability and quality of studies for inclusion using the Consolidated Standards of Reporting Trials guidelines. We meta-analysed data using a random-effects model.

RESULTS

We included seven studies including 1147 patients in the systematic review, of which 867 had AVGs and 280 had AVFs. One study was an ongoing RCT. In the meta-analyses, we assessed patients with failing AVGs only. Overall risk of bias was moderate. Covered stents were associated with lower loss of patency versus angioplasty alone at 6, 12 and 24 months (OR 4.48, 95% CI 1.98 to 10.14, p<0.001; OR 4.07, 95% CI 1.74 to 9.54, p=0.001; OR 2.24, 95% CI 1.17 to 4.29, p=0.01, respectively). Covered stents afforded superior access circuit primary patency compared with angioplasty alone at 6 and 12 months (OR 1.91, 95% CI 1.31 to 2.80, p<0.001; OR 1.97, 95% CI 1.14 to 3.41, p=0.02, respectively). This was not significant at 24 months. There was no significant difference in loss of secondary patency between groups at 12 or 24 months (OR 0.74, 95% CI 0.45 to 1.23, p=0.25; OR 0.67, 95% CI 0.29 to 0.154, p=0.34, respectively).

CONCLUSION

Our results support use of covered stents over angioplasty alone, at 6, 12 and 24 months in failing AVGs. Further clinical trials are warranted.

Percutaneous coronary angioplasty versus coronary artery bypass grafting in the treatment of unprotected left main stenosis: updated 5-year outcomes from the randomised, non-inferiority NOBLE trial

BACKGROUND

Percutaneous coronary intervention (PCI) is increasingly used in revascularisation of patients with left main coronary artery disease in place of the standard treatment, coronary artery bypass grafting (CABG). The NOBLE trial aimed to evaluate whether PCI was non-inferior to CABG in the treatment of left main coronary artery disease and reported outcomes after a median follow-up of 3·1 years. We now report updated 5-year outcomes of the trial.

METHODS

The prospective, randomised, open-label, non-inferiority NOBLE trial was done at 36 hospitals in nine northern European countries. Patients with left main coronary artery disease requiring revascularisation were enrolled and randomly assigned (1:1) to receive PCI or CABG. The primary endpoint was major adverse cardiac or cerebrovascular events (MACCE), a composite of all-cause mortality, non-procedural myocardial infarction, repeat revascularisation, and stroke. Non-inferiority of PCI to CABG was defined as the upper limit of the 95% CI of the hazard ratio (HR) not exceeding 1·35 after 275 MACCE had occurred. Secondary endpoints included all-cause mortality, non-procedural myocardial infarction, and repeat revascularisation. Outcomes were analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT01496651.

FINDINGS

Between Dec 9, 2008, and Jan 21, 2015, 1201 patients were enrolled and allocated to PCI (n=598) or CABG (n=603), with 17 subsequently lost to early follow-up. 592 patients in each group were included in this analysis. At a median of 4·9 years of follow-up, the predefined number of events was reached for adequate power to assess the primary endpoint. Kaplan-Meier 5-year estimates of MACCE were 28% (165 events) for PCI and 19% (110 events) for CABG (HR 1·58 [95% CI 1·24-2·01]); the HR exceeded the limit for non-inferiority of PCI compared to CABG. CABG was found to be superior to PCI for the primary composite endpoint (p=0·0002). All-cause mortality was estimated in 9% after PCI versus 9% after CABG (HR 1·08 [95% CI 0·74-1·59]; p=0·68); non-procedural myocardial infarction was estimated in 8% after PCI versus 3% after CABG (HR 2·99 [95% CI 1·66-5·39]; p=0·0002); and repeat revascularisation was estimated in 17% after PCI versus 10% after CABG (HR 1·73 [95% CI 1·25-2·40]; p=0·0009).

INTERPRETATION

In revascularisation of left main coronary artery disease, PCI was associated with an inferior clinical outcome at 5 years compared with CABG. Mortality was similar after the two procedures but patients treated with PCI had higher rates of non-procedural myocardial infarction and repeat revascularisation.

FUNDING

Biosensors.

Costs Attributable to Arteriovenous Fistula and Arteriovenous Graft Placements in Hemodialysis Patients with Medicare coverage

INTRODUCTION

Hemodialysis (HD) in end-stage renal disease (ESRD) patients requires vascular access (VA) through an arteriovenous fistula (AVF), a prosthetic arteriovenous graft (AVG), or a central venous catheter. While AVF or AVG is commonly used for HD, the economic implications of AVF versus AVG use have not been fully established. We describe the healthcare resource utilization and costs of AVF and AVG use for incident ESRD patients in the United States.

METHODS

This observational cohort study of AVF and AVG placements used data from the United States Renal Data System to identify and follow access placements. AVF and AVG placements after ESRD onset for incident patients from 2012 to 2014 with continuous Medicare primary coverage were included. All-cause and access-related Medicare costs were averaged over the placement lifetime and expressed as per dialysis-month costs.

RESULTS

The analysis included 38,035 AVF placements and 12,789 AVG placements. Total all-cause monthly costs for AVF averaged USD 8,508; mean monthly costs were USD 3,027 for inpatient (IP), USD 3,139 for outpatient (OP), USD 1,572 for physician services, and USD 770 for other care settings. Access-related monthly costs averaged USD 1,699 and represented 20% of all-cause charges for AVFs. Mean all-cause monthly costs for AVG were USD 9,605; by setting monthly costs were USD 3,811 for IP, USD 3,034 for OP, USD 1,881 for physician services and USD 879 for other care settings. Access-related monthly costs averaged USD 2,656 and represented 28% of all-cause charges for AVGs.

DISCUSSION/CONCLUSIONS

This study indicates that costs due to VA are a significant burden on Medicare budgets and on patients. The factors driving access-related utilization and costs merit attention in future research. Both optimizing process of care and discovery innovation may significantly accelerate better stewardship of available healthcare resources.

[Huge periprosthetic (peritransplant) seroma of a femoropopliteal bypass graft]

Presented herein is a clinical case report of a huge periprosthetic seroma of a femoropopliteal bypass graft made of polytetrafluoroethylene with a follow-up period and unsuccessful conservative management of more than one year. At 15 months after the primary operation, the bypass graft was retrieved and replaced by a knitted vascular graft made of polyester and impregnated with absorbable modified gelatine to decrease porosity, without relapse of the process of transudation into the periprosthetic space. Histological study of the retrieved conduit demonstrated the absence of formation of the intimal layer on the inner surface of the graft and fibrous capsule on the external surface of the main part of the length of the prosthesis, which, apparently, had provided a possibility of long-term preservation of porosity of the material.

Creative Vascular Access Construction in Same Patient

INTRODUCTION

Creating and maintaining a functional vascular access(VA) is a critical factor in the survival of a dialysis patient. However, it will not function forever, implying a creative attitude from the vascular surgeon either to maintain its functionality or built a new one wherever possible, being it autologous or synthetic.

METHODS

Describe the VA history of a 59years-old male with morbid obesity and end-stage chronic kidney disease.

RESULTS

His VA construction started in2012 with failed attempts in both forearms until a functional brachiocephalic artery-venous fistula(AVF) in the right upper limb was achieved, but was deemed to ligation as severe venous hypertension secondary to central venous disease related to CVC use. As he had no good superficial conduit in the left arm we decided to harvest the deemed right cephalic vein and implant it in the left arm, creating an autologous arteriovenous shunt between the brachial artery and axillary vein(AV). Despite initial patency, it failed irreversibly weeks after creation. As no more superficial veins were available in the upper limbs, a prosthetic access was the next step. We decided for a hybrid graft(HG) between the left brachial artery and the AV because the patient biotope and a scarred axilla impeded a safe reintervention on the AV. This graft was being used since 2015 with multiple interventions for maintaining patency (PTA, segmental graft replacement and thrombectomies). Recently we noticed a significant diffuse prosthesis deterioration and reduced AVF flow with no possible segmental reconstruction. We were then forced to proceed with total graft substitution preserving the outflow stented segment of the HG, using an early cannulation graft(ECG) and prevent CVC use. After this successful reconstruction, the patient started hemodialysis on the following day with no intercurrences registered.

DISCUSSION

Generally, CVC's are related with poorer dialysis quality and patient survival.Hence, fighting for any other functional access is very important. The range of solutions will depend on the vascular surgeon capacities, imagination and device access. Once faced with no more feasible direct autologous access, there is a range of complex autologous fistulas, including veins translocations. When no more native vessel can be used for puncture, we still have a wide armamentarium (normal grafts, ECG or HG) that should be considered according to patient specifications. HG besides some hemodynamic advantages, can be very useful when the landing vessels are difficult to access. ECG offer the advantage of almost immediate cannulation, preventing CVC placement and its associated comorbidities.

On the relationship between competitive flow and FFT analysis of the flow waves in the left internal mammary artery graft in the process of CABG

BACKGROUND

During coronary artery bypass grafting (CABG), the ratio of powers of the fundamental frequency and its first harmonic (F0/H1) in fast Fourier transformation (FFT) analysis of the graft's flow waves has been used in the field of evaluation of the patency in anastomosis. But there is no report about using the FFT method to evaluate the magnitude of competitive flow. This study is aiming at exploring the relationship between competitive flow and FFT analysis of the flow waves in left internal mammary artery (LIMA) graft, and finding a new method to evaluate the magnitude of competitive flow.

METHODS

At first, establishing the CABG multiscale models of different stenosis in left anterior descending artery (LAD) to get different magnitude of competitive flows. Then, calculating the models by ANSYS-CFX and getting the flow waves in LIMA. Finally, analyzing the flow waves by FFT method and comparing the FFT results with the magnitude of competitive flow.

RESULTS

There is no relationship between competitive flow and F0/H1. As for F0/H2 and F0/H3, they both increase with the reduction of the stenosis in LAD. But the increase of F0/H3 is not obviously enough and it can't identify the significant competitive flow clearly, so it can't be used as the evaluation index. It is found that F0/H2 increases obviously with the increase of the competitive flow and can identify the significant competitive flow.

CONCLUSION

The FFT method can be used in the evaluation of competitive flow and the F0/H2 is the ideal index. High F0/H2 refers to the significant competitive flow. This method can be used during CABG to avoid the risk of competitive flow.

Remote Superficial Femoral Artery A Endarterectomy: Early Results for TASC D Lesions in Patients With Severe Ischemia

Endovascular treatment for Transatlantic Inter-Society Consensus (TASC) D lesions of the superficial femoral artery has been disappointing. This has been attributed to a bulking atheromatous plaque. Debulking the superficial femoral artery allows for a larger lumen, whereas covering the lumen with an endograft provides in-line flow. We evaluated the intermediate results of remote superficial femoral artery endarterectomy with covered endograft placement in 18 patients. Patient demographic, vascular laboratory, and preoperative data were gathered retrospectively. The procedure was technically successful in all the patients. The mean age was 62.2 ± 9.9 years. Ankle brachial index improved from 0.35 ± 0.1 to 0.86 ± 0.1. The cumulative 12-month primary patency was 42.2%, whereas assisted primary or secondary patency was 70.8%. Five endografts occluded within the 12 months. Two of those patients underwent subsequent femoral-to-below-knee bypass, whereas 2 had major amputations. Remote superficial femoral artery endarterectomy can be reasonably offered if an autogenous conduit is not available for revascularization of the superficial femoral artery.

Critical Limb Ischemia in the Dialysis-Dependent Patient: Infrainguinal Vein Bypass Is Justified

The combination of critical limb ischemia and end-stage renal failure (ESRF, ie, dialysis- dependent) represents severe systemic atherosclerosis and is associated with a very poor medium-term survival. Many nephrologists and surgeons advocate primary amputation. We examined the recent experience in this unit to determine whether infrainguinal bypass in these patients can be justified. Retrospective study of all patients with critical limb ischemia and ESRF undergoing surgery in a regional vascular and renal unit between January 1996 and May 2003. Forty-two patients with ESRF (median age 65 years) were referred with critical limb ischemia. Seventeen patients underwent 24 (7 bilateral) infrainguinal bypasses (17 autologous vein, 7 polytetrafluoroethylene [PTFE] conduit; tissue loss in 21/24, 88%), and 25 patients had primary major amputations of 32 limbs. Early occlusion occurred in 5 grafts (21%, all 5/5 PTFE). In-hospital mortality was 13% in the bypass group, 24% in the amputation group. Median in-hospital stay was 59 days in the bypass group, 46 days in the amputation group. Thirty-day, 1- and 2-year survival was 88%, 50%, and 33% in the bypass group; 83%, 39%, and 35% in the amputation group. The limb salvage rate was 66% at 1 year. Seventy-five percent (18/24) of operated on limbs (15/17 of vein grafts) avoided major amputation at follow-up (median 18 months) or death. The combination of critical limb ischemia and end- stage renal failure carries a poor medium-term survival independent of primary amputation or surgical revascularization. Infrainguinal bypass in selected cases with vein conduit can, however, allow the majority of these patients to avoid major limb amputation.

[Indices of intraoperative flowmetry, determining patency of grafts in the remote period after revascularization of the right coronary artery]

The authors studied the threshold values of ultrasound flowmetry concerning composite T-grafts, combined I-grafts, and autovenous shunts during revascularization of the right coronary artery (RCA), determining high risk for the development of shunt occlusion in the remote postoperative period. The retrospective study included a total of 223 patients subjected to revascularization of the RCA's basin with the help of composite T-grafts, combined I-grafts, and autovenous shunts. Depending on the method of bypass grafting of the RCA and its branches, all patients were subdivided into 3 groups: Group 1 was composed of 65 patients in whom the RCA basin was revascularized by a branch of the composite T-graft, Group 2 comprised 112 patients who endured autovenous aortocoronary bypass grafting, and Group 3 consisted of 46 patients in whom the RCA basin was shunted by a combined mammarovenous I-graft. The groups had no statistically significant differences on the main clinical and demographic parameters. Intraoperative assessment of the blood flow through the coronary shunts was carried out by means of ultrasound flowmetry. The remote results were evaluated based on the findings of the control coronaroshuntography which was carried out in all patients within the terms varying from 16 to 43 months. In the remote period in Group 1 patients (T-graft), 59 (90%) mammary shunts were patent, in Group 2 - 99 (88.4%) autovenous shunts, and in Group 3 (I-graft) 42 (95.5%) shunt were patent. Cumulative probability of freedom from shunt occlusion within the terms up to 3 years after surgery in Group 1 amounted to 82±0.5%, in Group 2 to 58±2.1%, and in Group 3 to 86±1.9%, with the differences between Group 2 and other groups being statistically significant (p=0.01). The Poisson regression analysis showed that the risk for graft occlusion increased by 10% with the resistance index in the branch of the T-graft from 4.0; by 8% with the resistance index in the autovein from 2.9; and by 3% with the index of resistance in the I-graft from 3.2. The conclusion was made that composite T-grafts and combined I-grafts demonstrated similar results of patency within the terms up to 3 years, possessing advantages over autovenous conduits while shunting the RCA basin. The optimal index of peripheral resistance for the autovein during revascularization of the RCA basin is up to 2.9; for the combined T-graft - up to 3.2, and for the composite T-graft - up to 4.0. Probability of shunt occlusion in the remote period does not depend upon the average volumetric blood velocity (Q<inf>mean</inf>) but is directly proportional to the value of the pulsatility index (Pi) which reflects the state of the distal bed.

[MID-TERM RESULTS OF ARTERIOVENOUS AXILLARY LOOP GRAFT ON CHEST FOR ESTABLISHING HEMODIALYSIS ACCESS]

OBJECTIVE

To explore the role of arteriovenous axillary loop graft (AVALG) on chest for establishing hemodialysis access in patients with chronic renal failure.

METHODS

A retrospective analysis was made on the clinical data of 12 patients with chronic renal failure who underwent an AVALG on chest for hemodialysis access between December 2010 and May 2014. There were 2 males and 10 females with an average age of 65.25 years (range, 46-75 years). The main causes were chronic glomerulonephritis in 6 cases, diabetic nephropathy in 4 cases, and both kidney resection because of urinary tract tumors in 2 cases. The disease duration was 2-12 years (mean, 6 years). The 12 patients all underwent 5-14 times (mean, 7 times) failed prior vascular accesses [arteriovenous fistula (AVF) and arteriovenous graft (AVG)] leading to exhaustion of venous access sites on the upper extremities.

RESULTS

The AVALG on chest were functionally useful for hemodialysis access, 2-3 times per week, and the blood flow was 250-350 mL/minute; the average time for the first dialysis was 48 days (range, 42-93 days). All patients were followed up 12-54 months (mean, 20.92 months). There was no death during perioperative period. The primary patency rates at 6 and 12 months were 91.7% and 83.3% respectively, and the secondary patency rates at 6 and 12 months were both 100%. After operation, infection (1 case), thrombosis (2 cases), bleeding (2 cases), and swollen (1 case) occurred, which were all cured after corresponding treatment.

CONCLUSION

AVALG on chest is a supplementary option for chronic renal failure patients with inadequate upper extremity venous access sites after repeat occlusion.

Influence of gender on EVAR outcomes with new low-profile devices

Women have not benefitted to the same extent as men of endovascular abdominal aortic repair (EVAR). Besides differences in hormones and the higher rate of undiagnosed cardiovascular disease, there are anatomical differences between men and women influencing the outcome of endovascular treatment of abdominal aortic aneurysms (AAA). After the first decade of EVAR procedures, only 28% of women with an elective AAA were treated by EVAR due to their poor anatomical suitability for this technique. The anatomical challenges and their associated poorer outcomes suggest the need for advances in device design to better meet the specific female aneurysm anatomy and physiology. Most of the newer-generation endografts have been associated with lower incidences of graft occlusion compared with first-generation endografts, and might be more suitable for women. It is encouraging that EVAR has decreased long-term mortality in women and that women's survival begins to equal men's after 2 years. However, detailed, adjusted anatomical data from population-based samples are needed for better understanding of the differences in AAA anatomy and EVAR eligibility. This information will contribute to enhance the design, testing and evaluation of future stent grafts, to ensure that women will benefit from EVAR to the same extent as men.

Preliminary evidence supporting the safety of drug-eluting stents in neurovascular disease

OBJECTIVE

Restenosis is a significant complication of stent placement. With coronary revascularization, drug-eluting stents have significantly decreased the incidence of in-stent stenosis and, therefore, the morbidity of the procedure. Restenosis is potentially a significant problem for neurovascular disease. We therefore report our institutional experience on the use of drug-eluting stents for the management of cerebrovascular insufficiency.

METHODS

Over a period of 2 years, 19 patients underwent extra- and intracranial drug-eluting stent placement for intra- and extracranial atherosclerotic disease. There were 12 males and seven females aged between 36 and 83 years old (mean 65). Thirteen heparin, three rapamycin, and three taxus-coated stents were placed. There were five intracranial internal carotid arteries, two intracranial vertebral arteries, three mid-basilar, six of vertebral artery origin and three middle cerebral artery stents utilized. No complications occurred.

RESULTS

There was one case of re-stenosis associated with recurrent symptoms requiring repeat drug eluting stent placement. No other patients have developed new or recurrent neurological symptoms. Five of six vertebral artery origin stents were placed with distal protection to prevent embolic complications.

CONCLUSION

Intracranial and extracranial drug-eluting stent placement appears to be a safe alternative to the medical management of atherosclerotic disease of the vertebrobasilar and carotid systems. However, further randomized studies are needed to examine the effectiveness and safety of this procedure.

Current status of pipeline embolization device in the treatment of intracranial aneurysms: a review

OBJECTIVE

Pipeline embolization device (PED) implantation is a novel endovascular treatment option for the treatment of intracranial aneurysms. It is emerging as a useful alternative to coiling and to open surgery, and its use is increasing worldwide. We performed a literature review to examine its efficacy, technical challenges, and safety.

METHODS

PubMed database was used to identify all articles relating to PED.

RESULTS

The review outlines the indications for PED, its technical aspects, complications, and clinical outcomes.

CONCLUSIONS

PED offers an alternative to endovascular coiling for aneurysms with complex morphology. The indication for its use has evolved from the limited scope of treatment of giant aneurysms with wide necks to the inclusion of smaller aneurysms. The procedural safety profile of PED is comparable with or possibly superior to balloon-remodeling or stent-assisted coil embolization in specific circumstances. However, questions remain regarding the incidence of post-procedural subarachnoid hemorrhage. Ongoing monitoring and meticulous documentation of PED postimplantation safety is strongly recommended.

The evolution of cardiovascular stent materials and surfaces in response to clinical drivers: a review

This review examines cardiovascular stent materials from the perspective of a range of clinical drivers and the materials that have been developed in response to these drivers. The review is generally chronological and outlines how stent materials have evolved from initial basic stainless steel devices all the way through to the novel biodegradable devices currently being explored. Where appropriate, pre-clinical or clinical data that influenced decisions and selections along the way is referenced. Opinions are given as to the merit and direction of various ongoing and future developments.

Minimally invasive direct coronary artery bypass grafting: a meta-analysis

AIM

Recently minimally invasive direct coronary artery bypass (MIDCAB) grafting has become an interesting alternative to conventional coronary artery bypass grafting, especially in patients with a high-grade left anterior descending coronary artery (LAD) stenosis unsuitable for balloon angioplasty. Although MIDCAB offers several advantages such as the avoidance of sternotomy and cardiopulmonary bypass, concerns have been raised about the technical accuracy of the anastomoses that can be performed on a beating heart. Therefore, clinical and angiographic outcomes after MIDCAB are the subject of current controversy.

METHODS

A literature search for all published outcome studies of MIDCAB grafting was performed for the period from January 1995 through October 2007. Seventeen articles were enrolled in this meta-analysis. The data presented in the studies was analyzed with regard to clinical and angiographic results.

RESULTS

Early and late (>30 days after MIDCAB) death rates were 1.3% (51/4081 patients) and 3.2% (130/4081 patients), respectively. The infarct rate was 0.8% (32/4081 patients; non-fatal myocardial infarction). Other minor or major complications (e.g. reoperation for management of bleeding, chest wound problems, arrhythmias, cerebrovascular accident, pericardial effusion, pulmonary complications) were reported in 781 cases. The conversion rate to sternotomy/cardiopulmonary bypass was 1.8% (74/4081 patients). A re-intervention due to graft failure was necessary in 134/4081 patients (3.3%). A total of 2556 grafts were studied angiographically immediately after surgery. One hundred and six grafts (4.2%) were occluded and 169 grafts (6.6 %) had a significant stenosis (50-99%). At 6-month follow-up, 445 grafts were studied angiographically. Sixteen grafts (3.6%) were occluded and 32 grafts (7.2%) had a significant stenosis.

CONCLUSION

Clinical outcomes and immediate graft patency after MIDCAB are acceptable. However, long-term follow-up results and further randomized prospective clinical trials comparing this new technique with standard revascularization procedures in large patient cohorts are needed.

[Reliability of skin paddle in monitoring blood flow after free fibular osteocutaneous composite flap transfer]

OBJECTIVE

To evaluate the reliability of skin paddle in monitoring blood flow after free fibular osteocutaneous composite flap transfer.

METHODS

Seven hundred and fourteen consecutive cases of mandibular or maxillary reconstruction using free fibular flap from May 1999 to September 2007 were reviewed. The cases with postoperative vessel thrombosis were analyzed.

RESULTS

Postoperative vessel thrombosis occurred in 23 cases, 17 were venous and 6 arterial. Among 14 cases of venous thrombosis with color change of skin paddles, only 6 were successfully salvaged, but 3 cases with no color change of skin paddles were all successfully salvaged. For arterial thrombosis, only one flap was successfully salvaged. The postoperative vessel thrombosis rate was 3.2%, and the salvage rate was 43.5%. The overall successful rate of free fibula flap was 98.2%.

CONCLUSIONS

Postoperative vessel thrombosis can not be detected in the early stage if only observing the color change of skin paddle after free fibula flap transfer.

Heparin-bonded expanded polytetrafluoroethylene grafts for infragenicular bypass in patients with critical limb ischemia: 2-year results

AIM

The use of prosthetic grafts in below-knee (BK) bypasses may be necessary in patients with no available autologous vein and critical limb ischemia not amenable to angioplasty. Such conduits, however, have generally yielded disappointing results.

METHODS

A new heparin-bonded expanded polytetrafluoroethylene graft (Gore-Tex Propaten Vascular Graft) designed to provide resistance to thrombosis may be associated with decreased early graft failure and increased patency. This graft was implanted in 27 limbs (26 patients; 18 men; mean age 71 years; Rutherford class 4 to 6 disease) in a BK femoropopliteal and femorodistal location, without perioperative complications and with immediate graft patency.

RESULTS

During a mean follow-up time of 24 months, 4 cases of thrombosis occurred, all at least 6 months postoperatively: 2 cases resolved after fibrinolytic treatment, 1 required surgical revision and in 1 case, amputation was required because of a delay in seeking treatment for thrombosis. Two patients died of cardiac disease during follow-up. The 2-year primary and secondary patency rates for the BK bypasses were 85% and 93%, respectively; the limb-salvage rate was 96%.

CONCLUSION

These results are encouraging for a prosthetic graft, especially in the light of the severity of the vascular disease in the limbs treated.

Validation of numerical simulation with PIV measurements for two anastomosis models

Hemodynamics is widely believed to influence coronary artery bypass graft (CABG) stenosis. Although distal anastomosis has been extensively investigated, further studies on proximal anastomosis are still necessary, as the extent and initiation of the stenosis process may be influenced by the flow of the proximal anastomosis per se. Therefore, in this study, two models (i.e. 90 degrees and 135 degrees anastomotic models) were designed and constructed to simulate a proximal anastomosis of CABG for the left and right coronary arteries, respectively. Flow characteristics for these models were studied experimentally in order to validate the simulation results found earlier. PIV measurements were carried out on two Pyrex glass models, so that the disturbed flow (stagnation point, flow separation and vortex) found in both proximal anastomosis models using numerical simulation, could be verified. Consequently, a fair agreement between numerical and experimental data was observed in terms of flow characteristics, velocity profiles and wall shear stress (WSS) distributions under both steady and pulsatile flow conditions. The discrepancy was postulated to be due to the difference in detailed geometry of the physical and computational models, due to manufacturing limitations. It was not possible to reproduce the exact shape of the computational model when making the Pyrex glass model. The analysis of the hemodynamic parameters based on the numerical simulation study also suggested that the 135 degrees proximal anastomosis model would alleviate the potential of intimal thickening and/or atherosclerosis, more than that of a 90 degrees proximal anastomosis model, as it had a lower variation range of time-averaged WSS and the lower segmental average of WSSG.

The advantages of end-to-side arteriovenous anastomosis over the other two types of arteriovenous anastomosis in dialysis patients

The functional duration of vascular access in dialysis patients depends on the emergence of threatening complications. Discussions are constantly being held in an attempt to discover their causality and decrease their emergence. In 260 patients undergoing haemodialysis, we have studied the potential existence of a cause-and-effect relation between the emergence of complications in the vascular access and the applied type of arteriovenous (av.) anastomosis in the arteriovenous (AV) fistula. We have observed the incidence of all complications, both that of the thrombosis incidence as well as the primary and secondary fistula patency (survival). The complications--The examinees with the end-to-end anastomosis showed the incidence of 8.08%, 6.15% of the patients with the end-to-side anastomosis and 7.31% of the patients with the side-to-side anastomosis. The differences regarding incidences are statistically significant (chi2-test = 29.25; P = 0.0001). Thrombosis--it has been found that thrombosis was the most frequent complication developing in 30.00% patients with the end-to-end av. anastomosis, in 2.31% patients with end-to-side av. anastomosis and in 5.56% patients with side-to-side av. anastomosis. The difference between the highest and the lowest assessment is 27.69%, and it is statistically relevant (chi2-test = 33.920; P = 0.0001). The primary patency (primary survival): within a 6-month interval following the establishment of vascular access, the first complications arose in 62.50% of patients with end-to-end av. anastomosis, 10.76% in those with end-to-side av. anastomosis and 18.88% in those with side-to-side av. anastomosis. The difference between the highest and the lowest assessment is 51.74%, which is statistically significant (chi2-test = 49.009; P = 0.0001). The secondary patency: 24 months subsequent to the establishment of vascular access, the AV-fistula was still functional in 52.50% of the patients with end-to-end av. anastomosis, 89.23% in those with end-to-side av. anastomosis and 81.11% in those with side-to-side av. anastomosis. The difference between the highest and the lowest assessment is 36.73%, which is also statistically significant (chi2-test = 26.579; P = 0.0001). According to our research, the end--to-side type of av. anastomosis in vascular access provides better results both in relation to the duration as well as the maintenance of the functionality of the Av-fistula and in the lower incidence of the complications than the other types, and hence it shows a definite advantage.

[Problem of restenosis inside stents with an antiproliferative coating]

The article deals with a review of clinical studies carried out within the time period from 2003 to 2007. The review contains the data concerning restenoses of sirolimus- and paclitaxel-eluting stents, suggesting that the stents with an antiproliferative coating substantially diminished the acuity of the problem regarding restenoses but did not solve the problem completely. The incidence rate of restenoses remains high in patients with diabetes mellitus as well as in those with bifurcation stenoses, acute and chronic occlusions of coronary arteries. Analysing the published data the authors made a conclusion that during angioplasty of acute and chronic occlusions of coronary arteries preference should be given to sirolimus-eluting stents since they are most effective in prevention of restenoses inside stents in such lesions. Analysing the findings of clinical trials of drug-eluting stents showed efficiency and safety of such stents in treatment of in-stent restenoses. Patients with diabetes mellitus are exceptions to this rule, being poor candidates for drug-eluting stents, since the latter proved to exhibit low efficacy in these patients.