Endovascular bypass as a strategy for long femoropopliteal lesions

INTRODUCTION

Endovascular treatment has become the predominant treatment modality for femoropopliteal lesions. In longer and more complex lesions advanced technology is often required to improve results, with the endovascular bypass being one of them.

EVIDENCE ACQUISITION

A systematic review of the literature was performed to determine the clinical and technical outcomes of the latest generation endoprosthesis, with heparin bioactive surface and contoured proximal edge.

EVIDENCE SYNTHESIS

13 articles were enrolled: 3 randomized controlled trials, 4 prospective multicenter trials and 6 retrospective studies. The VIASTAR trial showed that the endoprosthesis has a better two-year primary patency compared to bare metal stenting, especially in long lesions (62% vs. 27%, P=0.004). The SUPERB trial showed that the endoprosthesis had similar results compared to bypass surgery, albeit with less complications (31% vs. 55%, P=0.048). The RELINE study showed that treatment with an endoprosthesis had a better one-year primary patency compared to balloon angioplasty for in-stent restenosis (75% vs. 28%, P<0.001). In the cohort studies one-year patency rates ranged from 61% to 86% for primary patency, from 65% to 92% for primary assisted patency, and from 83% to 95% for secondary patency.

CONCLUSIONS

For long femoropopliteal lesions, the heparin-bonded endoprosthesis is related to better outcomes compared to bare nitinol stents, and comparable outcomes as with the femoropopliteal bypass, but with less complications. There is a wide range in primary patency rates, with consistent high secondary patency rates. The endovascular bypass can be considered an appropriate strategy in these patients.

Evaluation of electrocardiogram-gated computed tomography angiography to quantify changes in geometry and dynamic behavior of the iliac artery after placement of the Gore Excluder Iliac Branch Endoprosthesis

BACKGROUND

The GORE^® EXCLUDER^® Iliac Branch Endoprosthesis (IBE) is designed to treat iliac aneurysms with preservation of blood flow through the internal iliac artery (IIA). Little is known about the influence of IBE placement on the IIA geometry. This study aimed to provide detailed insights in the dynamic behavior and geometry of the common iliac artery (CIA) and IIA trajectory and how these are influenced after treatment with an IBE.

METHODS

Pre- and postoperative electrocardiogram-gated computed tomography angiography (ECG-gated CTA) scans were acquired in a prospective study design and analyzed with in-house written algorithms designed for aorto-iliac and endoprosthesis deformation evaluation. Cardiac pulsatility-induced motion patterns and pathlengths were computed by tracking predefined locations on the aorto-iliac tract. Centerlines through the CIA-IIA trajectory were used to investigate the static and dynamic geometry, including curvature, torsion, length and Tortuosity Index (TI).

RESULTS

Fourteen CIA-IIA trajectories were analyzed before and after IBE placement. Cardiac pulsatility-induced motion and pathlengths increased after IBE placement, especially at mid IIA and the first IIA bifurcation (P≤0.04). After IBE placement, static and dynamic curvature, length and TI decreased significantly (P<0.05). Furthermore, the average dynamic torsion increased significantly (P=0.030). The remaining geometrical outcomes were not statistically significant.

CONCLUSIONS

The placement of an IBE device stiffens and straightens the CIA-IIA trajectory. Its relation with clinical outcome is yet to be investigated, which can be done thoroughly with the ECG-gated CTA algorithms used in this study.

Editor's Choice - Nationwide Analysis of Patients Undergoing Iliac Artery Aneurysm Repair in the Netherlands

OBJECTIVE

The new 2019 guideline of the European Society for Vascular Surgery (ESVS) recommends consideration for elective iliac artery aneurysm (eIAA) repair when the iliac diameter exceeds 3.5 cm, as opposed to 3.0 cm previously. The current study assessed diameters at time of eIAA repair and ruptured IAA (rIAA) repair and compared clinical outcomes after open surgical repair (OSR) and endovascular aneurysm repair (EVAR).

METHODS

This retrospective observational study used the nationwide Dutch Surgical Aneurysm Audit (DSAA) registry that includes all patients who undergo aorto-iliac aneurysm repair in the Netherlands. All patients who underwent primary IAA repair between 1 January 2014 and 1 January 2018 were included. Diameters at time of eIAA and rIAA repair were compared in a descriptive fashion. The anatomical location of the IAA was not registered in the registry. Patient characteristics and outcomes of OSR and EVAR were compared with appropriate statistical tests.

RESULTS

The DSAA registry comprised 974 patients who underwent IAA repair. A total of 851 patients were included after exclusion of patients undergoing revision surgery and patients with missing essential variables. eIAA repair was carried out in 713 patients, rIAA repair in 102, and symptomatic IAA repair in 36. OSR was performed in 205, EVAR in 618, and hybrid repairs and conversions in 28. The median maximum IAA diameter at the time of eIAA and rIAA repair was 43 (IQR 38-50) mm and 68 (IQR 58-85) mm, respectively. Mortality was 1.3% (95% CI 0.7-2.4) after eIAA repair and 25.5% (95% CI 18.0-34.7) after rIAA repair. Mortality was not significantly different between the OSR and EVAR subgroups. Elective OSR was associated with significantly more complications than EVAR (intra-operative: 9.8% vs. 3.6%, post-operative: 34.0% vs. 13.8%, respectively).

CONCLUSION

In the Netherlands, most eIAA repairs are performed at diameters larger than recommended by the ESVS guideline. These findings appear to support the recent increase in the threshold diameter for eIAA repair.

Endovascular versus surgical revascularization in proximal subclavian artery obstruction

BACKGROUND

The aim of this paper was to compare the outcomes of endovascular versus surgical treatment in patients with symptomatic proximal subclavian artery obstruction through a retrospective clinical study. Treatment of symptomatic subclavian artery obstruction can be performed with percutaneous transluminal angioplasty or open surgical reconstruction. Comparative studies are scarce.

METHODS

Technical success, patency and complication rates of 47 endovascular reconstructions in 46 patients were retrospectively compared with those of 19 open surgical reconstructions in 17 patients performed between 1996 and 2012. An additional series of 51 surgical reconstructions performed in the same institution between 1976 and 1993 served as a reference.

RESULTS

The technical success rate was 79% for endovascular and 100% for open surgical reconstructions (P<0.05). Primary patency was 72% and 89% at 1 year or 54% and 55% at 5 years for the endovascular and open surgical groups, respectively (log rank 0.210, P=0.65). Assisted primary patency was 77% and 100% at 1 year or 67% and 67% at 5 years, respectively (log rank 0.528, P=0.47). There was no mortality and major complications were infrequent, occurring equally in both groups (P=0.22).

CONCLUSIONS

Although with its less invasive character endovascular treatment has gained preference over surgical treatment of proximal subclavian obstruction in many cases, extrathoracic surgical reconstruction can be performed with a higher technical success rate, similar patency and a comparable number of complications.

Validation of pre-procedural aortic aneurysm volume calculations to estimate procedural fill volume of endobags in endovascular aortic sealing

BACKGROUND

Endovascular aortic sealing (EVAS) with a sac anchoring endoprosthesis excludes abdominal aortic aneurysms based on polymer filling of endobags. Primary objective was to assess the reliability of pre-procedural computed tomography (CT) scans based calculations of required endobag volume in relation to intraoperative volume of the endobags.

METHODS

Forty elective EVAS patients were included. Pre-procedural estimations of endobag volume were based on CT segmentations of aortic flow lumen volume, including both automated and manually-adjusted segmentations, performed by two experienced users. Additionally, changes in maximum AAA diameter, thrombus volume and total AAA volume were calculated from pre- and post-procedural CT scans.

RESULTS

Automatically determined volumes were comparable to manually-adjusted calculations (75.3 vs. 75.7 mL) and inter-observer agreement regarding pre-EVAS calculations of prefill volume appeared almost perfect with an intra-class correlation coefficient of 0.98 (95% CI: 0.96-0.99). The mean pressure of the endobags was 185 mmHg. Manually-adjusted pre-procedural volume calculations underestimated procedural volume of the endobags (-11.3±9.9 mL). Differences between pre-EVAS and procedural volume measurements were independent from endobag pressure (r=-0.06, P=0.72), prepocedural thrombus volume (r=-0.303, P=0.057) and changes in total AAA volume (r=0.02, P=0.91). A significant association was determined between differences in pre-EVAS and endobag volume versus changes in thrombus volume pre- and post-procedural (r=0.39, P=0.01).

CONCLUSIONS

In this validation study, pre-procedural volume measurements underestimate the actual fill volume of the endobags. It should be advised to perform a prefill of the endobags during the EVAS procedure.

Polyanionic polysaccharides reduce intra-abdominal adhesion and abscess formation in a rat peritonitis model

BACKGROUND

Intra-abdominal infection is complicated by adhesion and abscess formation. We have assessed the adhesion- and abscess-reducing capacity of various solution volumes and concentrations of two polyanionic polysaccharides, hyaluronan (HA) and carboxymethylcellulose (CMC), in a rat peritonitis model.

STUDY DESIGN

In 192 male Wistar rats a bacterial peritonitis was induced using cecal ligation and puncture. After 24 h the abdomen was reopened and the ligated cecum resected. Animals were randomized into three control groups, nine groups treated with various solution volumes (1 to 8 ml) containing different HA concentrations, and four groups treated with 1.7% CMC solution. Rats were killed at day 7, postoperatively, and adhesions were scored at five abdominal sites on a scale from 0 to 4. The presence and size of intra-abdominal abscesses were noted.

RESULTS

Fifty-four rats (28%) prematurely died. There was no significant difference in mortality between treatment groups and controls. Treatment with CMC (P < 0.001) and low (0.2 and 0.4%) concentrations of HA (P < 0.005) significantly reduced intra-abdominal adhesion formation. High volumes of 0.2 and 0.4% HA were most effective (P = 0.01). The effect of CMC was volume independent. The incidence of abdominal abscesses was also significantly reduced by treatment with either CMC (P < 0.001) or low concentrations of HA (P < 0.001). With regard to abscess formation the effect was independent of the volume administered for HA, while low volumes of CMC were most effective (P < 0.005).

CONCLUSION

Intraperitoneal treatment with either CMC or low-viscosity HA solution reduced intra-abdominal adhesion and abscess formation in a rat peritonitis model. The volume-induced reduction in adhesion formation suggests a hydroflotation effect of HA solution.

Recent clinical developments in pathophysiology, epidemiology, diagnosis and treatment of intra-abdominal adhesions

Postsurgical intra-abdominal adhesions pose a significant medical problem in the Western world, and in the past decade progress has been made in understanding their pathophysiology. The early balance between fibrin formation and degradation in the peritoneal cavity during and after surgery seems to be a major determinant of adhesion formation. Postsurgical inhibition of fibrinolytic activity severely impairs fibrin breakdown. Adhesive small-bowel obstruction, inadvertent enterotomy at reoperation, prolonged operative time dividing adhesions, increased clinical workload and high financial costs are important adhesion-related problems discussed in this review. The cumulative risk of adhesive small-bowel obstruction after (sub)total colectomy is 11% within 1 year, increasing to 30% at 10 years. One of five patients undergoing reoperation suffers from inadvertent enterotomy, resulting in significant postoperative morbidity and mortality. Roughly 3% of all surgical admissions are associated with intra-abdominal adhesions. Clinical prospective trials have recently been designed to investigate the efficacy of barrier membranes and gels in the reduction of abdominal and pelvic adhesions and prevention of long-term morbidity, e.g., adhesive bowel obstruction and infertility in women. Early results are promising and contribute to the increased interest among clinicians in postsurgical adhesion formation and its consequences.

Sodium hyaluronate increases the fibrinolytic response of human peritoneal mesothelial cells exposed to tumor necrosis factor alpha

HYPOTHESIS

Sodium hyaluronate interferes with the fibrin degrading capacity of human peritoneal mesothelial cells exposed to tumor necrosis factor (TNF) alpha.

DESIGN

Controlled laboratory experiment.

INTERVENTION

Human peritoneal mesothelial cells were harvested from 5 patients undergoing laparotomy and cultured in vitro. Cells were treated with TNF-alpha, a cytokine typically involved in peritoneal inflammation, and sodium hyaluronate was added in a final concentration of 0.1%, 0.2%, or 0.4%. Controls received medium only. After 24 hours' incubation, tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), and plasminogen activator inhibitor type 1 (PAI-1) were measured in the medium and cell lysates using enzyme-linked immunosorbent assay techniques. Specific gene transcripts in cells treated with 0.4% sodium hyaluronate and controls were determined using a quantitative reverse transcription polymerase chain reaction.

MAIN OUTCOME MEASURES

Concentrations of tPA, uPA, and PAI-1, and their specific gene transcripts.

RESULTS

Sodium hyaluronate significantly increased tPA concentration in cell lysates without affecting its gene expression as determined after 24 hours (P =.02). The uPA concentration was significantly decreased by sodium hyaluronate in the medium but not in cell lysates (P<.0001). The uPA messenger RNA expression was 1000-fold increased compared with control. Sodium hyaluronate significantly decreased PAI-1 concentration in the medium and reduced its gene expression 500-fold (P =.04), while PAI-1 concentration in cell lysates did not change.

CONCLUSION

Sodium hyaluronate affected the fibrinolytic response of TNF-alpha-stimulated human peritoneal mesothelial cells, most notably by decreasing PAI-1 transcription and release. This observation indicates that sodium hyaluronate counteracts the fibrinolytic decline induced by TNF-alpha and suggests a biological mechanism of action for sodium hyaluronate intra-abdominally.

Hyaluronic acid-based agents do not affect anastomotic strength in the rat colon, in either the presence or absence of bacterial peritonitis

BACKGROUND

Hyaluronic acid (HA) agents reduce postsurgical adhesion formation. The effect of their perioperative administration on early anastomotic healing is unknown. This study investigated the influence of two HA-containing agents on the development of strength in colonic anastomosis during the first postoperative week, both in normal rats and in rats with bacterial peritonitis.

METHODS

In 90 male Wistar rats a 1-cm segment was resected from the descending colon and an end-to-end anastomosis was constructed. In 108 rats a bacterial peritonitis was induced using caecal ligation and puncture (CLP). Some 24 h after CLP the abdomen was reopened, the caecum was taken out and, after resection of a 1-cm segment, an anastomosis was made. Animals in both groups were randomized to receive either an HA-carboxymethylcellulose (CMC) bioresorbable membrane, 0.4 per cent HA solution or no treatment. One-third of each group was killed at day 1, 3 and 7 after operation. Cultures were taken from the abdominal cavity for microbiological analysis in half of the animals. Subsequently, both bursting pressure and breaking strength were determined as parameters for anastomotic strength.

RESULTS

No differences in anastomotic bursting pressure or breaking strength were found between the experimental groups and their controls. In addition, there was no significant difference in the number of bacteria cultured from the abdominal cavity between rats treated with HA and controls.

CONCLUSION

Neither HA-CMC bioresorbable membrane nor 0.4 per cent HA solution interferes with the development of early anastomotic strength in the colon, and can therefore be safely used to prevent intra-abdominal adhesion formation after performing bowel anastomosis.

The antiadhesive agent sodium hyaluronate increases the proliferation rate of human peritoneal mesothelial cells

OBJECTIVE

Evaluating the influence of sodium hyaluronate on the proliferation rate of attached and nonattached human peritoneal mesothelial cells to elucidate whether this is a possible mechanism of action in peritoneal tissue repair.

DESIGN

Controlled laboratory experiment.

SETTING

A university hospital.

PATIENT(S)

Five patients undergoing colorectal surgery for noninfectious reasons.

INTERVENTION(S)

Human peritoneal mesothelial cells were harvested from patients undergoing a laparotomy for noninfectious reasons. Cells, both nonattached and attached, were incubated for 4 and 24 hours with different concentrations of sodium hyaluronate. Thereafter, the cell proliferation rate was measured by XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-car boxanilide) colorimetric assay. To mimic peritoneal injury, the cells were exposed to tumor necrosis factor alpha and/or lipopolysaccharide and were incubated immediately or after 24 hours of exposure to 0% or 0.2% sodium hyaluronate. Afterward, the cell proliferation rate was measured.

MAIN OUTCOME MEASURE(S)

Proliferation rate measured by XTT assay.

RESULT(S)

Sodium hyaluronate significantly increased the proliferation rate of mesothelial cells, both in a nonattached (P<.005) and attached (P<.001) state. Exposure of the mesothelial cells to tumor necrosis factor alpha and/or lipopolysaccharide diminished the cells' proliferation rate. However, incubation of these exposed cells with 0.2% sodium hyaluronate significantly increased the proliferation rate, regardless of whether the sodium hyaluronate was added immediately (P<.001) or after 24 hours (P<.001).

CONCLUSION(S)

Sodium hyaluronate increases the proliferation rate of human peritoneal mesothelial cells, both attached and nonattached, under normal conditions and after stimulation with tumor necrosis factor alpha and/or lipopolysaccharide.

Morbidity and mortality of inadvertent enterotomy during adhesiotomy

BACKGROUND

Inadvertent enterotomy is a feared complication of adhesiotomy during abdominal reoperation. The nature and extent of this adhesion-associated problem are unknown.

METHODS

The records of all patients who underwent reoperation between July 1995 and September 1997 were reviewed retrospectively for inadvertent enterotomy, risk factors were analysed using univariate and multivariate parameters, and postoperative morbidity and mortality rates were assessed.

RESULTS

Inadvertent enterotomy occurred in 52 (19 per cent) of 270 reoperations. Dividing adhesions in the lower abdomen and pelvis, in particular, caused bowel injury. In univariate analysis body mass index was significantly higher in patients with inadvertent enterotomy (mean(s.d.) 25.5(4.6) kg/m2 ) than in those without enterotomy (21.9(4.3) kg/m2 ) (P < 0.03). Patient age and three or more previous laparotomies appeared to be independent parameters predicting inadvertent enterotomy (odds ratio (95 per cent confidence interval) 1.9 (1.3-2.7) and 10.4 (5.0-21.6) respectively; P < 0.001). Patients with inadvertent enterotomy had significantly more postoperative complications (P < 0.01) and urgent relaparotomies (P < 0.001), a higher rate of admission to the intensive care unit (P < 0.001) and parenteral nutrition usage (P < 0.001), and a longer postoperative hospital stay (P < 0.001).

CONCLUSION

The incidence of inadvertent enterotomy during reoperation is high. This adhesion-related complication has an impact on postoperative morbidity

Prevention of intra-abdominal abscesses and adhesions using a hyaluronic acid solution in a rat peritonitis model

HYPOTHESIS

Hyaluronic acid (HA)-based bioresorbable membrane and 0.4% HA solution reduce intraabdominal adhesion and abscess formation in a rat peritonitis model.

DESIGN

Randomized laboratory experiment.

SETTING

A university hospital.

INTERVENTIONS

In 72 male Wistar rats, a bacterial peritonitis was induced using the cecal ligation and puncture model. Animals were randomized to receive isotonic sodium chloride solution (group 1), HA-carboxymethylcellulose bioresorbable membrane (group 2), or 0.4% HA solution (group 3). Half of each group were killed at day 7 and half at day 21, and adhesions were scored in a blind fashion. The presence and sizes of intra-abdominal abscesses were noted. Cultures were taken for bacterial analysis.

MAIN OUTCOME MEASURES

Intra-abdominal adhesions and abscesses.

RESULTS

The median severity of adhesions was significantly lower in group 3 compared with group 1 rats at day 7 (II [range, I-IV] vs IV [range, I-IV], respectively; P=.02) and at day 21 (II [range, I-III vs IV [range, II-IV], respectively; P=.02). There was no significant difference between group 2 and group 1 rats on either day. At day 7, abscesses larger than 2 cm were found in 6 of 12 group 1 rats and in 4 of 12 group 2 rats, but in 0 of 11 group 3 rats (P=.01). At day 21, 0 of 11 group 3 rats had an intra-abdominal abscess, in contrast to 4 (33%) of 12 group 1 rats and 5 (45%) of 11 group 2 rats. All cultures of abscesses revealed polymicrobial flora.

CONCLUSION

Adhesion and abscess formation are reduced using a 0.4% HA solution, and not HA-carboxymethylcellulose bioresorbable membrane, in a rat model of generalized bacterial peritonitis.

Imaging experimental intraabdominal abscesses with 99mTc-PEG liposomes and 99mTc-HYNIC IgG

OBJECTIVE

To evaluate the accuracy of technetium-99m-labeled polyethylene glycol-coated liposomes (99mTc-PEG liposomes) and technetium-99m-labeled nonspecific human immunoglobulin G (99mTc-HYNIC IgG) for the scintigraphic detection of experimental intraabdominal abscesses in comparison with that of a standard agent, gallium-67 citrate.

BACKGROUND

Scintigraphic imaging techniques can be very useful for the rapid and accurate localization of intraabdominal abscesses. Two newly developed radiolabeled agents, 99mTc-PEG liposomes and 99mTc-HYNIC IgG, have shown to be excellent agents for imaging experimental focal infection, but have not yet been studied in the detection of abdominal abscesses.

METHODS

Intraabdominal abscesses were induced in 42 rats using the cecal ligation and puncture technique. Seven days later, randomized groups of rats received 99mTc-PEG liposomes, 99mTc-HYNIC IgG, or 67Ga citrate intravenously. The rats were imaged up to 24 hours after the injection. The biodistribution of the radiolabel was determined by counting dissected tissues ex vivo. Macroscopic intraabdominal abnormalities and focal uptake on the images were independently scored on a semiquantitative scale.

RESULTS

99mTc-PEG liposomes provided the earliest scintigraphic visualization of the abscess (as soon as 2 hours after the injection vs. 4 hours for the other two agents). Liposomes, IgG, and gallium all showed similarly high absolute uptake in the abscess. Focal uptake of liposomes and gallium correlated best with the extent of the macroscopic abnormalities.

CONCLUSIONS

99mTc-PEG liposomes and 99mTc-HYNIC IgG performed at least as well as the standard agent, 67Ga citrate, in the detection of experimental intraabdominal abscesses, with obvious advantages such as lower radiation exposure and more favorable physical properties. Of the two technetium agents, the liposomes seemed to be superior, providing the earliest diagnostic image and the best correlation with the inflammatory abnormalities. In addition, the preferential localization of radiolabeled PEG liposomes holds promise for targeted delivery of liposome-encapsulated drugs.

Small bowel obstruction after total or subtotal colectomy: a 10-year retrospective review

BACKGROUND

The aim of this retrospective study was to determine the cumulative incidence of adhesive small bowel obstruction (SBO) after total or subtotal colectomy and to investigate the site of the obstructive adhesions in the abdominal cavity.

METHODS

The records of 234 patients who underwent colectomy from 1985 to 1994 were reviewed for SBO, potential risk factors for SBO, and the site of adhesions causing obstruction. Mean follow-up, which was complete in 215 patients, was 63 months.

RESULTS

SBO occurred in 56 patients (24 per cent) of whom 42 (18 per cent) had adhesive obstruction. The risk of SBO due to adhesions within 1 year was 11 per cent, increasing to 30 per cent 10 years after colectomy. With univariate analysis no risk factor for adhesive SBO, including previous laparotomies, septic complications and omental resection, was identified. The most common site of obstructing adhesions was the pelvis (ten of 28 patients).

CONCLUSION

The incidence of SBO after colectomy is high. Colectomy may be a suitable model for studies of adhesion prevention.