Vascularization of the arteriovenous fistula wall and association with maturation outcomes

BACKGROUND AND OBJECTIVES

The venous vasa vasorum is the mesh of microvessels that provide oxygen and nutrients to the walls of large veins. Whether changes to the vasa vasorum have any effects on human arteriovenous fistula outcomes remains undetermined. In this study, we challenged the hypothesis that inadequate vascularization of the arteriovenous fistula wall is associated with maturation failure.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

This case-control pilot study includes pre-access veins and arteriovenous fistula venous samples (i.e. tissue pairs) from 30 patients undergoing two-stage arteriovenous fistula creation (15 matured and 15 failed to mature). Using anti-CD31 immunohistochemistry, we quantified vasa vasorum density and luminal area (vasa vasorum area) in the intima, media, and adventitia of pre-access veins and fistulas. We evaluated the association of pre-existing and postoperative arteriovenous fistula vascularization with maturation failure and with postoperative morphometry.

RESULTS

Vascularization of veins and arteriovenous fistulas was predominantly observed in the outer media and adventitia. Only the size of the microvasculature (vasa vasorum area), but not the number of vessels (vasa vasorum density), increased after arteriovenous fistula creation in the adventitia (median vasa vasorum area 1366 µm2/mm2 (interquartile range 495-2582) in veins versus 3077 µm2/mm2 (1812-5323) in arteriovenous fistulas, p < 0.001), while no changes were observed in the intima and media. Postoperative intimal thickness correlated with lower vascularization of the media (r 0.53, p = 0.003 for vasa vasorum density and r 0.37, p = 0.045 for vasa vasorum area). However, there were no significant differences in pre-existing, postoperative, or longitudinal change in vascularization between arteriovenous fistulas with distinct maturation outcomes.

CONCLUSION

The lack of change in intimal and medial vascularization after arteriovenous fistula creation argues against higher oxygen demand in the inner walls of the fistula during the vein to arteriovenous fistula transformation. Postoperative intimal hyperplasia in the arteriovenous fistula wall appears to thrive under hypoxic conditions. Vasa vasorum density and area by themselves are not predictive of maturation outcomes.

Arachnoid bands and venous compression as rare causes of hemifacial spasm: analysis of etiology in 353 patients

BACKGROUND

Hemifacial spasm is usually caused by arterial compression at the root exit zone of the facial nerve. However, other etiologies have been reported. The aim of this study was to analyze the frequency of other causes of hemifacial spasm.

METHODS

Our prospectively maintained hemifacial spasm database containing all patients who underwent microvascular decompression (MVD) for hemifacial spasm from 2002 to 2018 was reviewed. All offending structures were identified and recorded by the surgeon at the time of surgery. Additionally, the operative videos were analyzed retrospectively.

RESULTS

MVD was performed in 353 patients. Arterial compression was the main cause of hemifacial spasm in 341 (96.9%) patients. Combined venous-arterial compression was seen in 7 (2.0%) patients. In one patient, the compression was from a large vein. In two patients, no compression was found. One patient who suffered from Bell's palsy many years previously had severe synkinesis and the other had facial tics. In two patients, the spasm was caused due to strangulation of the facial nerve by arachnoid bands. Long-term follow-up of more than 18 months was available in 249 patients with total resolution or near total resolution of spasms in 89.96% of patients.

CONCLUSIONS

In most patients with hemifacial spasm, arterial vessels are involved in compressing the facial nerve. Purely venous compression is rarely encountered. We report for the very first time arachnoid bands strangulating the nerve as a cause for hemifacial spasm without involvement of any vessel.

Radial artery-first dorsal metacarpal vein arteriovenous fistula in the first interdigital space of the dorsal hand for hemodialysis

A radiocephalic arteriovenous fistula in the anatomical snuffbox (tabatière region) was first described in 1969 as the most peripheral site for arteriovenous fistula in the upper limb. In cases in which the internal diameter of the first dorsal metacarpal vein under avascularization is ⩾2.0 mm, we have adopted a new operative technique for creating a radial artery-first dorsal metacarpal vein arteriovenous fistula in the first interdigital space of the dorsal hand, which lies between the thumb and the index finger. This technique is the creation of the arteriovenous fistula using the first dorsal metacarpal vein and the most peripheral site in the upper limb. To our knowledge, no previous report has described the creation of a radial artery-first dorsal metacarpal vein arteriovenous fistula. We herein describe the steps of the technique and report its successful performance in a patient with chronic renal failure.

Major venous injury and large volume crystalloid resuscitation: A limb threatening combination

INTRODUCTION

Major venous injury (MVI) affecting the lower extremity can result in subsequent amputation. The contribution of intraoperative resuscitation efforts on the need for amputation is not well defined. We hypothesized that intraoperative large volume crystalloid resuscitation (LVCR) increases the risk of amputation after MVI, while massive transfusion (MT) does not.

METHODS

We performed a retrospective review of patients with infrarenal MVI from 2005 to 2015 at seven urban level I trauma centers. The outcome of interest was the need for secondary amputation.

RESULTS

478 patients were included. 31 (6.5%) patients with MVI required amputation. LVCR(p < 0.001), combined arterial/venous injury (p = 0.001), and associated fracture (p = 0.001) were significant risk factors for amputation. MT did not significantly increase amputation risk (p = 0.44). Multivariable logistic regression model demonstrated that patients receiving ≥5L LVCR(aOR (95% CI): 9.7 (2.9, 33.0); p < 0.001), with combined arterial/venous injury (aOR (95% CI):3.6 (1.5, 8.5); p = 0.004), and with an associated fracture (aOR (95% CI):3.2 (1.5, 7.1); p = 0.004) were more likely to require amputation.

CONCLUSION

Patients with MVI who receive LVCR, have combined arterial/venous injuries and have associated fractures are more likely to require amputation. MT was not associated with delayed amputation.

Left spermatic vein reflux after varicocele repair predicts pregnancies and live births in subfertile couples

PURPOSE

Varicocele repair (VR) is proposed to improve fertility in subfertile couples with a poor semen quality. We explored whether the disappearance of a left continuous spermatic venous reflux (SVR) at scrotal colour-Doppler ultrasound (CDUS), an objective evidence for a VR, is predictive for improved fertility outcome in subfertile couples.

METHODS

VR was performed by left internal spermatic vein sclero-embolisation in 88 males seeking a consultation for subfertility. Semen analysis and scrotal CDUS were evaluated before and 6 months after VR. Serum levels of FSH and total testosterone (TT) were obtained at baseline. Telephone interview was used to obtain information about fertility outcome. Significant predictors of pregnancy and live births, selected by univariate analyses, were included into multiple logistic regression models to assess independent associations.

RESULTS

At the adjusted model, independent significant predictors of pregnancy after VR were a disappeared SVR at CDUS (OR = 5.5, 97.5% CI 2.01-15.4; p = 0.0009) and an improved sperm total motile count (TMC) (OR = 5.5, 97.5% CI 1.4-27.9; p = 0.02). Even live births were independently associated with both disappeared left SVR at CDUS (OR = 4.3, 97.5% CI = 1.6-11.8; p = 0.003) and improved TMC after VR (OR = 4.8, 97.5% CI 1.3-24.2; p = 0.02).

CONCLUSION

The still controversial effect of varicocele repair on fertility in subfertile couples may reside on the undefined objective methods to document a successful VR and its effect on couple fertility. The disappearance of a continuous left SVR at CDUS after VR was the objective best predictor for subsequent improved fertility in subfertile couples.

Creation of Arteriovenous Fistulas and Grafts Concomitantly with Endovascular Correction of Outflow Veins: A Hybrid Procedure

BACKGROUND

Achieving well-functioning dialysis fistulas is a common problem in dialyzed patients, and it is mainly caused by the pathologies of vessels used for fistula creation. Hybrid therapies, combining surgical and endovascular procedures, potentially enable the creation of functional dialysis fistulas in patients with vessels that are otherwise unsuitable for vascular access.

METHODS

Between January 1, 2014 and June 30, 2018, we created dialysis fistulas simultaneously with endovascular correction of outflow pathologies in 15 patients. The included patients had a long history of dialysis (median 10.5 years, range 3-22) and many previous dialysis access procedures (mean 5.3 procedures, range 2-9). In 13 patients (86.7%), the fistula was created on the upper arm; in 5 patients (33.3%), it was arteriovenous graft done with polytetrafluoroethylene (PTFE) prosthesis (in an additional 3 patients, a PTFE prosthesis was used to extend the vein), and 7 patients had native vessel fistulas (46.7%). Endovascular procedures, in some cases performed on more than 1 vein, were applied for correction of the subclavian vein (8 patients, 53.3%); brachiocephalic vein (6 patients, 40.0%); cephalic, basilic, and axillary veins (2 patients each, 13.3%); and superior cava vein (1 patient, 6.7%). Access for the endovascular procedure was achieved through a dissected vein used for arteriovenous anastomosis. The fistula function was monitored, and all complications of dialysis access were noted. The median follow-up in the observed group was 18 months. We compared the patency of dialysis fistula creation combined with endovascular correction of outflow vein pathology to our results of standard dialysis fistula operations: radiocephalic dialysis fistula creation (RCAVF group, 65 patients) and dialysis fistula stenosis angioplasty (PTA group, 30 patients).

RESULTS

The 12- and 24-month primary patency rates of dialysis fistulas created in hybrid procedures with simultaneous outflow vein pathology correction were 72.7% and 63.6%, respectively. No early complications related to endovascular or open procedures were observed.

CONCLUSIONS

A hybrid procedure for the creation of a dialysis fistula with the simultaneous correction of outflow pathologies enables a properly functioning dialysis fistula to be obtained. This procedure can be performed in patients with complicated vascular situations, enabling the creation of dialysis fistulas. Our results of hybrid procedures, involving simultaneous endovascular correction of the outflow vein with dialysis fistula creation, showed the efficiency and good results.

A Comparative Study Regarding Deep and Superficial Veins for Venous Outflow in Forearm Loop Arteriovenous Grafts

BACKGROUND

The purpose of the study was to compare the access patency rates of forearm loop arteriovenous grafts (AVGs) using deep veins and superficial veins for venous outflow.

METHODS

The medical records of patients on dialysis were retrospectively reviewed to identify the individual risk factors and the outcomes of forearm loop AVGs according to their outflow types.

RESULTS

Overall, 170 cases were enrolled in this study. Of these, 103 cases (60.6%) used deep veins for outflow. Most patients using deep vein outflow had their venous anastomosis above the elbow (P = 0.000). Patients with venous anastomosis above the elbow were more likely to be female (P = 0.049) and have a lower albumin level (P = 0.025). The primary patency rates for superficial vein outflow and deep view outflow were 35.5% and 29.4% at 12 months and 18.9% and 4.9% at 24 months, respectively. There was a statistically significant difference between the two groups (P = 0.013). The assisted primary patency rates for superficial venous outflow and deep vein outflow were 85.5% and 79.5% at 12 months and 73.2% and 59.6% at 24 months, respectively (P = 0.139). Primary and assisted primary patency rates did not differ according to the crossing of the elbow.

CONCLUSIONS

The primary patency rate of AVGs using deep veins for outflow was inferior to AVGs using superficial veins. But the assisted primary patency rate showed no difference. The use of a deep vein for outflow in the forearm loop AVG is a safe strategy for patients with exhausted superficial veins.

Protocol for a systematic review and meta-analysis of interventions for pathologic perforator veins in chronic venous disease

INTRODUCTION

Perforator veins (PVs) play an important role in the development of chronic venous insufficiency and ulceration. Procedures to eliminate incompetence and reflux in PV may include open surgery, subfascial endoscopic surgery, intravenous ablation techniques and sclerotherapy. With the aim of filling the evidence gap, this is a protocol for a systematic review that will assess the effects of any form of intervention for the treatment of pathologic PVs of the lower limbs in patients with chronic venous disease.

METHODS AND ANALYSIS

Systematic searches will be carried out in MEDLINE, EMBASE, Cochrane CENTRAL, IBECS and LILACS databases at a minimum without date or language restrictions for relevant randomised controlled trials (RCTs) and quasi-RCTs (trials in which the method of allocation is not truly random). In addition, a search will also be carried out in the WHO International Clinical Trials Registry Platform, in the clinical trial registries of ClinicalTrials.gov and in the grey literature source OpenGrey.eu. The RCT and quasi-RCT comparison techniques isolated or in combination for treating PVs will be considered. Three review authors will independently perform data extraction and quality assessments of data from included studies, and any disagreements will be resolved by discussion. The primary outcomes will be wound healing and pain. Secondary outcomes will include oedema, adverse events, recurrence or recanalisation, quality of life and economic aspects. The Cochrane handbook will be used for guidance. If the results are not appropriate for a meta-analysis in RevManV.5 software (eg, if the data have considerable heterogeneity and are drawn from different comparisons), a descriptive analysis will be performed.

ETHICS AND DISSEMINATION

Ethics committee approval is not necessary. We intend to update the public registry used in this review, report any important protocol amendments and publish the results in a widely accessible journal.

PROSPERO REGISTRATION NUMBER

CRD42018092974.

Subfascial endoscopic perforator surgery (SEPS) for treating venous leg ulcers

BACKGROUND

Venous leg ulcers are complex, costly, and their prevalence is expected to increase as populations age. Venous congestion is a possible cause of venous leg ulcers, which subfascial endoscopic perforator surgery (SEPS) attempts to address by removing the connection between deep and superficial veins (perforator veins). The effectiveness of SEPS in the treatment of venous leg ulcers, however, is unclear.

OBJECTIVES

To assess the benefits and harms of subfascial endoscopic perforator surgery (SEPS) for the treatment of venous leg ulcers.

SEARCH METHODS

In March 2018 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of interventions that examined the use of SEPS independently or in combination with another intervention for the treatment of venous leg ulcers.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, assessed risk of bias, and assessed the certainty of evidence using the GRADE approach.

MAIN RESULTS

We included four RCTs with a total of 322 participants. There were three different comparators: SEPS plus compression therapy versus compression therapy (two trials); SEPS versus the Linton procedure (a type of open surgery) (one trial); and SEPS plus saphenous surgery versus saphenous surgery (one trial). The age range of participants was 30 to 82, with an equal spread of male and female participants. All trials were conducted in hospital settings with varying durations of follow-up, from 18 months to 6 years. One trial included participants who had both healed and active ulcers, with the rest including only participants with active ulcers.There was the potential for reporting bias in all trials and performance bias and detection bias in three trials. Participants in the fourth trial received one of two surgical procedures, and this study was at low risk of performance bias and detection bias.SEPS + compression therapy versus compression therapy (2 studies; 208 participants)There may be an increase in the proportion of healed ulcers at 24 months in people treated with SEPS and compression therapy compared with compression therapy alone (risk ratio (RR) 1.17, 95% confidence interval (CI) 1.03 to 1.33; 1 study; 196 participants); low-certainty evidence (downgraded twice, once for risk of bias and once for imprecision).It is uncertain whether SEPS reduces the risk of ulcer recurrence at 24 months (RR 0.85, 95% CI 0.26 to 2.76; 2 studies; 208 participants); very low-certainty evidence (downgraded three times, twice for very serious imprecision and once for risk of bias).The included trials did not measure or report the following outcomes; time to complete healing, health-related quality of life (HRQOL), adverse events, pain, duration of hospitalisation, and district nursing care requirements.SEPS versus Linton approach (1 study; 39 participants)It is uncertain whether there is a difference in ulcer healing at 24 months between participants treated with SEPS and those treated with the Linton procedure (RR 0.95, 95% CI 0.83 to 1.09; 1 study; 39 participants); very low-certainty evidence (downgraded three times, twice for very serious imprecision and once for risk of bias).It is also uncertain whether there is a difference in risk of recurrence at 60 months: (RR 0.47, 95% CI 0.10 to 2.30; 1 study; 39 participants); very low-certainty evidence (downgraded three times, twice for very serious imprecision and once for risk of bias).The Linton procedure is possibly associated with more adverse events than SEPS (RR 0.04, 95% CI 0.00 to 0.60; 1 study; 39 participants); very low-certainty evidence (downgraded three times, twice for very serious imprecision and once for risk of bias).The outcomes time to complete healing, HRQOL, pain, duration of hospitalisation and district nursing care requirements were either not measured, reported or data were not available for analysis.SEPS + saphenous surgery versus saphenous surgery (1 study; 75 participants)It is uncertain whether there is a difference in ulcer healing at 12 months between participants treated with SEPS and saphenous surgery versus those treated with saphenous surgery alone (RR 0.96, 95% CI 0.64 to 1.43; 1 study; 22 participants); very low certainty evidence (downgraded three times, twice for very serious imprecision and once for high risk of reporting bias).It is also uncertain whether there is a difference in the risk of recurrence at 12 months: (RR 1.03, 95% CI 0.15 to 6.91; 1 study; 75 participants); very low certainty evidence (downgraded three times, twice for very serious imprecision and once for high risk of reporting bias).Finally, we are uncertain whether there is an increase in adverse events in the SEPS group (RR 2.05, 95% CI 0.86 to 4.90; 1 study; 75 participants); very low certainty evidence (downgraded three times, twice for very serious imprecision and once for high risk of reporting bias).The outcomes time to complete healing, HRQOL, serious adverse events, pain, duration of hospitalisation, and district nursing care requirements were either not measured, reported or data were not available for analysis.

AUTHORS' CONCLUSIONS

The role of SEPS for the treatment of venous leg ulcers remains uncertain. Only low or very low-certainty evidence was available for inclusion. Due to small sample sizes and risk of bias in the included studies, we were unable to determine the potential benefits and harms of SEPS for this purpose. Only four studies met our inclusion criteria, three were very small, and one was poorly reported. Further high-quality studies addressing the use of SEPS in venous leg ulcer management are likely to change the conclusions of this review.

Multiple lymphatic-venous anastomoses (MLVA) for microsurgical drainage of primary peno-scrotal lymphedema: A case report

Single site Multiple Lymphatic-Venous Anastomoses (MLVA) provides optimal functional and cosmetic results with low complication rates in treatment of lower limb lymphedema. However, no evidence exists in literature concerning the use of this technique in treatment of peno-scrotal lymphedema. We report a case of a 44-year-old male patient who developed secondary peno-scrotal lymphedema with severe lymphorrhea, following a laser treatment for scrotal pustolosis, leading to recurrent infections and finally an established peno-scrotal lymphedema. Utilizing MLVA, a complete remission of scrotal lymphedema was achieved with significant volume reduction of the penile lymphedema. The post-operative course was uneventful with clear improvement in lymphatic flow demonstrable on lymphoscintigraphy (6 months) and no recurrence of scrotal lymphedema at 2 years follow-up. This article reports very promising results of a novel application of MLVA in the treatment of genital lymphedema and suggests that MLVA provides the possibility to shunt both superficial and deep lymphatics to improve the lymphatic drainage from the peno-scrotal area using a single surgical site.

Spermatic vein aneurysm: a report of a unique case and review of the literature

A spermatic vessel aneurysm is a rare entity, described only a few times in the literature. In most cases, it is caused by trauma or inflammation and appears as a painful mass in the scrotum or the inguinal area. We present a case of a 22-year-old man who came to our Surgical Department with a painful, palpable mass in the right inguinal area. A spermatic vein aneurysm was diagnosed with the use of ultrasonography and it was surgically excised. The findings were confirmed by pathological examination. The patient is well, four months after surgery. A spermatic vessel aneurysm, though rare, should always be included in the differential diagnosis of a scrotal or inguinal mass. The lesion can be cured by surgical resection.

Molecular identity of arteries, veins, and lymphatics

BACKGROUND

Arteries, veins, and lymphatic vessels are distinguished by structural differences that correspond to their different functions. Each of these vessels is also defined by specific molecular markers that persist throughout adult life; these markers are some of the molecular determinants that control the differentiation of embryonic undifferentiated cells into arteries, veins, or lymphatics.

METHODS

This is a review of experimental literature.

RESULTS

The Eph-B4 receptor and its ligand, ephrin-B2, are critical molecular determinants of vessel identity, arising on endothelial cells early in embryonic development. Eph-B4 and ephrin-B2 continue to be expressed on adult vessels and mark vessel identity. However, after vascular surgery, vessel identity can change and is marked by altered Eph-B4 and ephrin-B2 expression. Vein grafts show loss of venous identity, with less Eph-B4 expression. Arteriovenous fistulas show gain of dual arterial-venous identity, with both Eph-B4 and ephrin-B2 expression, and manipulation of Eph-B4 improves arteriovenous fistula patency. Patches used to close arteries and veins exhibit context-dependent gain of identity, that is, patches in the arterial environment gain arterial identity, whereas patches in the venous environment gain venous identity; these results show the importance of the host infiltrating cells in determining vascular identity after vascular surgery.

CONCLUSIONS

Changes in the vessel's molecular identity after vascular surgery correspond to structural changes that depend on the host's postsurgical environment. Regulation of vascular identity and the underlying molecular mechanisms may allow new therapeutic approaches to improve vascular surgical procedures.

Abnormalities of vascular histology and collagen fiber configuration in patients with advanced chronic kidney disease

INTRODUCTION:

Several histologic features have been identified in the upper-extremity arteries and veins of patients with advanced chronic kidney disease, which may affect arteriovenous fistula maturation. However, it is unclear whether these chronic kidney disease vascular features are abnormal.

METHODS:

We obtained upper-extremity arterial and venous specimens from 125 advanced chronic kidney disease patients undergoing arteriovenous fistula creation and from 15 control subjects. We quantified medial fibrosis, micro-calcification, and intimal hyperplasia with appropriate histology stains. We characterized medial collagen fiber configuration in second-harmonic-generation microscopy images for the fiber anisotropy index and the dominant fiber direction.

RESULTS:

The advanced chronic kidney disease patients were significantly younger than control subjects (53 ± 14 years vs 76 ± 11 years, p < 0.001). After controlling for age, the chronic kidney disease patients had greater arterial medial fibrosis (69% ± 14% vs 51% ± 10%, p < 0.001) and greater arterial micro-calcification (3.03% ± 5.17% vs 0.01% ± 0.03%, p = 0.02), but less arterial intimal thickness (30 ± 25 µm vs 63 ± 25 µm, p < 0.001), as compared to control subjects. The anisotropy index of medial collagen fibers was lower in both arteries (0.24 ± 0.10 vs 0.44 ± 0.04, p < 0.001) and veins (0.28 ± 0.09 vs 0.53 ± 0.10, p < 0.001) in chronic kidney disease patients, indicating that orientation of the fibers was more disordered. The dominant direction of medial collagen fibers in chronic kidney disease patients was greater in the arteries (49.3° ± 23.6° vs 4.0° ± 2.0°, p < 0.001) and the veins (30.0° ± 19.6° vs 3.9° ± 2.1°, p < 0.001), indicating that the fibers in general were aligned more perpendicular to the lumen.

CONCLUSION:

Advanced chronic kidney disease is associated with several abnormalities in vascular histology and collagen fiber configuration. Future research is needed to investigate whether these abnormalities affect the maturation outcomes of arteriovenous fistulas.

Protocol for a systematic review of venous coupler devices versus hand-sewn anastomosis for microsurgical free flap reconstruction

BACKGROUND

A patent microvascular anastomosis is of paramount importance in free tissue transfer. Anastomotic coupler devices provide an alternative to technically demanding hand-sewn venous anastomosis. Various advantages of these devices have been discussed but previous systematic reviews had methodological flaws or did not perform a meta-analysis. This review aims to evaluate the quality of the evidence and quantify the efficacy and safety of venous couplers compared to hand-sewn anastomosis.

METHODS

A PRISMA-compliant systematic review and meta-analysis will be performed. A comprehensive search strategy has been developed and will be applied to the databases MEDLINE and Embase from inception to October 2018. All clinical studies using anastomotic coupler devices for venous anastomoses in free tissue transfer will be eligible for inclusion. Screening of studies and data extraction will be performed independently by two authors. Our primary outcome is anastomotic venous thrombosis. Secondary outcomes will include time to complete the venous anastomosis, tearing of veins, anastomotic leakage, flap loss/failure and fiscal outcomes. The risk of bias for included studies will be assessed by using the ROBINS-I tool, and recommendations based on the evidence will be made using the GRADE approach. Descriptive statistical analyses will be used and if two or more studies report the same outcome, data will be pooled for comparative analysis. A direct comparison meta-analysis will be performed if possible.

DISCUSSION

There has been no comparison of coupled and hand-sewn venous anastomoses using a robust and validated methodology preceded by a protocol and performing meta-analysis. Included studies are expected to be mainly observational and prone to bias; however, there is value in summarising the evidence, assessing its risk of bias and performing meta-analysis to guide clinicians. By using a broad approach including all types of flaps, we foresee inherent differences regarding the unit of analysis and different anatomic sites. This will limit the validity of our conclusions but is unavoidable. We will seek unpublished data from authors and perform subgroup analysis where appropriate. Limitations and areas of uncertainty will be discussed to guide future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018110111.

A preoperative nomogram predicts prognosis of up front resectable patients with pancreatic head cancer and suspected venous invasion

BACKGROUND

Pancreatic head adenocarcinoma is commonly diagnosed at an advanced stage when adjacent vascular invasion is present. This study aimed to establish a preoperative prognostic nomogram for patients who underwent attempted curative resectional surgery for pancreatic head cancer with suspected peripancreatic venous invasion.

METHODS

Data on all consecutive patients were retrospectively collected from 2012 to 2016 at four academic institutions. The demographic and radiological parameters were analyzed using univariate and multivariate Cox regression analyses. The final nomogram was established using the concordance Harrell's C-indices and calibration curves from data obtained in three institutions and validated in the cohort of patients coming from the fourth institution.

RESULTS

The nomogram was constructed using data from 178 patients while the validation cohort consisted of 61 patients. Age, length of tumor contact, peripancreatic venous abnormalities and lymph node staging were independent factors of overall survival. The nomogram showed good probabilities of survival on calibration curves. The C-index of the model in predicting overall survival (OS) was 0.824 for the validation cohort.

CONCLUSIONS

The nomogram accurately predicted OS in patients with pancreatic head cancer with suspected peripancreatic venous invasion after attempted curative pancreatic resectional surgery.

Postoperative Ultrasound, Unassisted Maturation, and Subsequent Primary Patency of Arteriovenous Fistulas

BACKGROUND AND OBJECTIVES

Postoperative ultrasound is commonly used to assess arteriovenous fistula (AVF) maturation for hemodialysis, but its utility for predicting unassisted AVF maturation or primary AVF patency for hemodialysis has not been well defined. This study assessed the predictive value of postoperative AVF ultrasound measurements for these clinical AVF outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We queried a prospective vascular access database to identify 246 patients on catheter-dependent hemodialysis who underwent AVF creation between 2010 and 2016 and obtained a postoperative ultrasound within 90 days. Multivariable logistic regression was used to evaluate the association of clinical characteristics and postoperative ultrasound measurements with unassisted AVF maturation. A receiver operating characteristic curve estimated the predictive value of these factors for unassisted AVF maturation. Finally, multivariable survival analysis was used to identify factors associated with primary AVF patency in patients with unassisted AVF maturation.

RESULTS

Unassisted AVF maturation occurred in 121 out of 246 patients (49%), assisted maturation in 55 patients (22%), and failure to mature in 70 patients (28%). Using multivariable logistic regression, unassisted AVF maturation was associated with AVF blood flow (odds ratio [OR], 1.30; 95% confidence interval [95% CI], 1.18 to 1.45 per 100 ml/min increase; P<0.001), forearm location (OR, 0.37; 95% CI, 0.08 to 1.78; P=0.21), presence of stenosis (OR, 0.45; 95% CI, 0.23 to 0.88; P=0.02); AVF depth (OR, 0.88; 95% CI, 0.77 to 1.00 per 1 mm increase; P=0.05), and AVF location interaction with depth (OR, 0.50; 95% CI, 0.28 to 0.84; P=0.02). The area under the receiver operating characteristic curve, using all these factors, was 0.84 (95% CI, 0.79 to 0.89; P<0.001). Primary AVF patency in patients with unassisted maturation was associated only with AVF diameter (hazard ratio, 0.84; 95% CI, 0.76 to 0.94 per 1 mm increase; P=0.002).

CONCLUSIONS

Unassisted AVF maturation is predicted by AVF blood flow, location, depth, and stenosis. AVF patency after unassisted maturation is predicted only by the postoperative AVF diameter.

Factors Contributing to Morbidity after Combined Arterial and Venous Lower Extremity Trauma

The purpose of this study was to evaluate the impact of management of venous injury on clinical outcomes in patients with combined lower extremity arterial and venous trauma. Patients with common and external iliac, common and superficial femoral, and popliteal artery injuries were identified. Patients who underwent vein repair and those who received vein ligation were compared. The analysis was repeated for those patients who required secondary intervention for their arterial injury and those who did not require secondary intervention. Seventy patients were identified with both arterial and venous injuries: 40 underwent vein ligation and 30 received vein repair. There was no difference in ischemic time between patients undergoing vein repair compared with ligation. Vein ligation did not produce a higher incidence of muscle debridement (10% vs 15%, P = 0.72), necessity for secondary intervention (10% vs 7.5%, P = 0.99), or amputation (3.3% vs 7.5%, P = 0.63). Patients who required secondary intervention had a greater degree of shock on presentation (packed red blood cells (PRBC), 13 units vs 6 units, P = 0.02) and were more likely to require muscle debridement (50% vs 9%, P = 0.02) and amputation (33% vs 3%, P = 0.03). Vein ligation did not impact muscle ischemia or success of arterial repair in patients with combined venous and arterial trauma in the lower extremities. Patient morbidity after extremity vascular trauma is most related to degree of shock.

[Surgical treatment for lymphoedema]

Lymphoedema is a frequent condition after surgical treatment for breast cancer. Lymphoedema causes great discomfort for the patients and is primarily treated conservatively with compression garments and physical therapy. Recently, surgical interventions have gained popularity in the form of lympho-lymphatic anastomoses, lympho-venous anastomoses and autologous lymph node transplantation, either as stand-alone treatment or in combination with secondary breast reconstruction. In Denmark, lympho-venous anastomoses is currently the primary surgical treatment for lymphoedema.

Usefulness of venous catheter as an intraluminal stent for end-to-end venous anastomosis

BACKGROUND

Venous anastomosis is one of the most difficult techniques in vascular neurosurgery.

METHOD

We present a simple technique of end-to-end venous anastomosis for reconstruction of accidentally injured vein. A venous catheter was used for the stent during the end-to-end anastomosis.

RESULTS

The venous catheter as the stent facilitated confirmation of the ostium of the vein. The venous end-to-end anastomosis was successfully performed.

CONCLUSIONS

Accidental venous injury can be reconstructed with the present simple technique.

The Use of Lympho-Venous Anastomoses to Prevent Complications from Ilio-Inguinal Dissection

Lympho-venous anastomoses (LVA) were performed in 30 patients, immediately after the completion of ilio-inguinal dissection for metastatic nodal involvement. This surgical procedure, originally devised to treat post-mastectomy lymphedema from radical mastectomy, was intended in this series of cases to prevent complications from ilio-inguinal nodal dissection. Actually, when compared to another group of 84 patients previously operated on by ilioinguinal nodal dissection without lympho-venous anastomoses, the series showed a lower rate of local-regional complications (38% vs 65.9%). The mean duration of hospital stay was also reduced (18.5 vs 34.7 days). Distant lymphedema of the lower limb was observed in 7 of 23 patients who had received LVA, whereas in the control group, lymphedema was recorded in 39 of 52 patients who were regularly followed-up (30% vs 75%). LVA should be routinely used, as a useful surgical procedure, to prevent or reduce the occurrence of local-regional complications following ilio-inguinal nodal dissections.

Assessment of veins in T2*-weighted MR angiography predicts infarct growth in hyperacute ischemic stroke

BACKGROUND AND PURPOSE

T2*-weighted magnetic resonance angiography (SWAN) detects hemodynamic insufficiency as hypointense areas in medullary or cortical veins. We therefore investigated whether SWAN can help predict ischemic penumbra-like lesions in patients with acute ischemic stroke (AIS).

MATERIALS AND METHODS

Magnetic resonance imaging (MRI) records-including SWAN, diffusion-weighted imaging (DWI), and magnetic resonance angiography (MRA)-of consecutive patients with major vessel occlusion within 6 h from AIS onset were analyzed. Acute recanalization was defined as an arterial occlusive lesion score of 2-3. A modified Alberta Stroke Program Early CT Score (mASPECTS) was used to evaluate ischemic areas revealed by SWAN and DWI. SWAN- and DWI-based mASPECTSs were calculated, and correlations between DWI-SWAN mismatches with final infarct lesions or clinical outcomes were evaluated.

RESULTS

Among the 35 patients included in this study, we confirmed cardioembolic stroke in 26, atherothrombotic stroke in 4, and unknown stroke etiology in 5. Overall, recanalization was achieved in 23 patients, who showed a higher follow-up DWI-based mASPECTS and lower modified Rankin Scale (mRS) score at 90 days than patients without recanalization. Initial SWAN- and follow-up DWI-based mASPECTSs were significantly higher for atherothrombotic stroke than for cardioembolic stroke. Of 12 patients without recanalization, DWI-SWAN mismatch was significantly correlated with infarct growth. Patients with recanalization showed no such correlation. In the assessment of clinical outcome, follow-up DWI-based mASPECTS and patient's age were significantly correlated with mRS at 90 days after stroke. A multivariate logistic regression analysis revealed that the follow-up DWI-based mASPECTS was independently associated with a favorable outcome 90 days after stroke.

CONCLUSIONS

For patients with AIS, DWI-SWAN mismatch might show penumbra-like lesions that would predict infarct growth without acute recanalization. Assessment of ischemic lesions from the venous side appears to be useful for considering the etiology and revascularization therapy.