Long-Term Results of Endovascular Treatment of Atherosclerotic Stenoses or Occlusions of the Coeliac and Superior Mesenteric Artery in Patients With Mesenteric Ischaemia

INTRODUCTION

Over the past decade, primary percutaneous mesenteric artery stenting (PMAS) has become an alternative to open revascularisation for treatment of mesenteric ischaemia. Institutes have presented favourable short-term outcomes after PMAS, but there is a lack of data on long-term stent patency.

METHODS

One hundred and forty-one patients treated by PMAS for acute and chronic mesenteric ischaemia over an 8 year period were studied. Anatomical success was assessed by duplex ultrasound and/or CT angiography. A stenosis ≥70% was considered to be a failure.

RESULTS

Eighty-six coeliac arteries (CA) and 99 superior mesenteric arteries (SMA) were treated with PMAS in 141 patients. Nine CAs (10%) and 30 SMAs (30%) were occluded at the time of treatment. Median follow-up was 32 months (IQR 20-46). The overall primary patency rate at 12 and 60 months was 77.0% and 45.0%. The overall primary assisted patency rate was 90.3% and 69.8%. Overall secondary patency was 98.3% and 93.6%.

CONCLUSION

This study shows excellent long-term secondary patencies after PMAS, comparable with published data on long-term patencies after open surgical revascularisation.

Colon ischemia: Right-sided colon involvement has a different presentation, etiology and worse outcome. A large retrospective cohort study in histology proven patients

BACKGROUND

Colon ischemia (CI), is generally considered a non-occlusive mesenteric ischemia disorder that usually runs a benign course, but right-sided involvement (RCI) has been associated with worse outcome. The poor outcome of RCI has been associated with comorbidity, but more recently also with occlusions of the mesenteric arteries. We performed a retrospective analysis of a large cohort of CI-patients to assess differences in presentation, etiology, and comorbidity between right-sided colon ischemia (RCI) and non-right-sided colon ischemia (NRCI), and their relation to outcome.

METHODS

We performed a retrospective cohort study in two centers from 2000 to 2011 for CI and analyzed clinical presentation, etiology, treatment and outcome. Diagnosis was based on full colonoscopy and/or surgical findings and confirmed by histopathology.

RESULTS

239 patients were included (mean age 69, 52% female). RCI was found in 48% and NRCI in 52%. Patients with NRCI presented more often with rectal bleeding (87% vs. 45%; p<0.001). In RCI more nausea (58% vs. 39%; p=0.013), weight loss (56% vs. 19%; p<0.001), paralytic ileus (32% vs. 18%; p=0.018) and peritoneal signs (27% vs. 7%; p<0.001) was observed compared to NRCI. The cause of CI was more often idiopathic in NRCI (46% vs. 26%; p=0.002); an occlusive cause was seen more often in RCI (26.3 vs 2.4%, p<0.0001). RCI patients had longer hospital stay (15 vs. 8 days, p<0.001), need for surgery (61% vs. 34%, p<0.001), and trend toward higher 30-day in-hospital mortality (20% vs. 12%, p=0.084).

CONCLUSIONS

RCI ischemia has different etiology, presentation, and outcome. The series shows a high proportion of - treatable - vessel occlusion. It reinforces the advice to perform CT angiography in RCI as means to improve its poor outcome.

Diagnosis and treatment of chronic mesenteric ischemia: An update

Although the prevalence of mesenteric artery stenoses (MAS) is high, symptomatic chronic mesenteric ischemia (CMI) is rare. The collateral network in the mesenteric circulation, a remnant of the extensive embryonal vascular network, serves to prevent most cases of ischemia. This explains the high incidence of MAS and relative rarity of cases of CMI. The number of affected vessels is the major determinant in CMI development. Most subjects with single vessel mesenteric stenosis do not develop ischemic complaints. Our experience is that most subjects with CA and SMA stenoses with abdominal complaints have CMI. A special mention should be made on patients with median arcuate ligament compression (MALS). There is ongoing debate whether the intermittent compression, caused by respiration movement, can cause ischemic complaints. The arguments pro and con treatment of MALS will be discussed. The clinical presentation of CMI consists of postprandial pain, weight loss, and an adapted eating pattern caused by fear of eating. In end-stage disease more continuous pain, diarrhea or a dyspepsia-like presentation can be observed. Workup of patients suspected for CMI consists of three elements: the anamnesis, the vascular anatomy and proof of ischemia. The main modalities to establish mesenteric vessel patency are duplex ultrasound, CT angiography or MR angiography. Assessing actual ischemia is still challenging, with only tonometry and visual light spectroscopy as tested candidates. Treatment consists of limiting metabolic demand, treatment of the atherosclerotic process and endovascular or operative revascularisation. Metabolic demand can be reduced by using smaller and more frequent meals, proton pump inhibition. Treatment of the atherosclerotic process consists of cessation of smoking, treatment of dyslipidemia, hypertension, hyperglycaemia, and medication with trombocyte aggregation inhibitors.

Chronic mesenteric ischemia: when and how to intervene on patients with celiac/SMA stenosis

BACKGROUND

Studies that compared open surgical mesenteric artery repair (OSMAR) with percutaneous mesenteric artery stenting (PMAS) in patients with chronic mesenteric ischemia (CMI) are based on merely older studies in which only a minority of patients received PMAS. This does not reflect the current PMAS-first choice treatment paradigm. This article focused on the present opinions and changes in outcomes of OSMAR for CMI in the era of preferred use of PMAS.

METHODS

Patients who received OSMAR for CMI from 1997 until 2014 in a tertiary referral centre for chronic mesenteric ischemia were included in this report. Patients were divided into two groups, the historical OSMAR preferred group and present PMAS preferred group.

RESULTS

Patient characteristics, SVS comorbidity severity score, clinical presentation and number of diseased mesenteric arteries were not significantly changed after the widespread introduction of PMAS. In the present PMAS first era there were trends of less open surgical mesenteric artery multivessel repair, less antegrade situated bypasses, decreased clinical success but improved survival after OSMAR.

CONCLUSIONS

Elective OSMAR should only be used in patients with substantial physiologic reserve and who have unfavourable mesenteric lesions, failed PMAS or multiple recurrences of in-stent stenosis/occlusion. PMAS in CMI patients is evolved from "bridge to surgery" to nowadays first choice treatment and "bridge to repeated PMAS" in almost all patients with CMI.

Meta-Analysis of Genome-Wide Association Studies for Abdominal Aortic Aneurysm Identifies Four New Disease-Specific Risk Loci

Supplemental Digital Content is available in the text.

Rationale:

Abdominal aortic aneurysm (AAA) is a complex disease with both genetic and environmental risk factors. Together, 6 previously identified risk loci only explain a small proportion of the heritability of AAA.

Objective:

To identify additional AAA risk loci using data from all available genome-wide association studies.

Methods and Results:

Through a meta-analysis of 6 genome-wide association study data sets and a validation study totaling 10 204 cases and 107 766 controls, we identified 4 new AAA risk loci: 1q32.3 (SMYD2), 13q12.11 (LINC00540), 20q13.12 (near PCIF1/MMP9/ZNF335), and 21q22.2 (ERG). In various database searches, we observed no new associations between the lead AAA single nucleotide polymorphisms and coronary artery disease, blood pressure, lipids, or diabetes mellitus. Network analyses identified ERG, IL6R, and LDLR as modifiers of MMP9, with a direct interaction between ERG and MMP9.

Conclusions:

The 4 new risk loci for AAA seem to be specific for AAA compared with other cardiovascular diseases and related traits suggesting that traditional cardiovascular risk factor management may only have limited value in preventing the progression of aneurysmal disease.

Validation of the Simbionix PROcedure Rehearsal Studio sizing module: A comparison of software for endovascular aneurysm repair sizing and planning

An important determinant of successful endovascular aortic aneurysm repair is proper sizing of the dimensions of the aortic-iliac vessels. The goal of the present study was to determine the concurrent validity, a method for comparison of test scores, for EVAR sizing and planning of the recently introduced Simbionix PROcedure Rehearsal Studio (PRORS). Seven vascular specialists analyzed anonymized computed tomography angiography scans of 70 patients with an infrarenal aneurysm of the abdominal aorta, using three different sizing software packages Simbionix PRORS (Simbionix USA Corp., Cleveland, OH, USA), 3mensio (Pie Medical Imaging BV, Maastricht, The Netherlands), and TeraRecon (Aquarius, Foster City, CA, USA). The following measurements were included in the protocol: diameter 1 mm below the most distal main renal artery, diameter 15 mm below the lowest renal artery, maximum aneurysm diameter, and length from the most distal renal artery to the left iliac artery bifurcation. Averaged over the locations, the intraclass correlation coefficient is 0.83 for Simbionix versus 3mensio, 0.81 for Simbionix versus TeraRecon, and 0.86 for 3mensio versus TeraRecon. It can be concluded that the Simbionix sizing software is as precise as two other validated and commercially available software packages.

Endarterectomy or carotid artery stenting: the quest continues part two

BACKGROUND

Although randomized trials on carotid artery stenting (CAS) could not establish its equivalence to carotid endarterectomy (CEA) in patients with symptomatic carotid disease, CAS is rapidly evolving. Data on long-term outcome after CAS from randomized trials have now become available and ongoing, prospectively held registries frequently publish their results in increasing numbers of patients. We have therefore reviewed the currently available literature and provide an update of our previous article on this topic.

DATA SOURCES

PubMed literature searches were performed to identify relevant studies regarding current status of CEA and stenting for symptomatic carotid stenosis.

CONCLUSIONS

The efficacy of CAS in patients with symptomatic carotid artery stenosis remains unclear because of varying results in randomized trials. Although multiple registries do report promising results after CAS, peri-interventional stroke/death rates still exceed those rates currently found after CEA. Therefore, CEA remains the "gold standard" in treating these patients.

Retrograde open mesenteric stenting for acute mesenteric ischemia

OBJECTIVE

Acute mesenteric ischemia (AMI) encompasses the sequels of end-stage untreated chronic mesenteric ischemia and acute mesenteric artery thrombosis. Percutaneous mesenteric artery stenting (PMAS) is the preferred treatment of patients with AMI but is not always feasible. Retrograde open mesenteric stenting (ROMS) is a hybrid technique that combines the advantages of open surgical and endovascular approaches. The literature on the results of this new technique is scarce. The aim of this study was to evaluate the results of ROMS in a consecutive series of patients with AMI.

METHODS

All patients with emergent mesenteric revascularization for AMI between January 2007 and September 2011 were entered in our prospective registry. Technical success, mortality, patency, clinical success, and complication rate at 30 days and 6 and 12 months were assessed.

RESULTS

Sixty-eight patients presented with AMI and 54 underwent PMAS, of which four were unsuccessful and followed by ROMS. Eleven patients were directly treated with ROMS, making a total of 15 patients (10 women and five men; median age, 66 years [interquartile range, 54-73 years]). In all patients, only the superior mesenteric artery was revascularized. In nine of the 15 patients, all three mesenteric arteries were severely stenotic or occluded. Technical success was achieved in 14 patients. At ROMS in two patients, the small bowel was severely ischemic. One of these patients needed a partial bowel resection because of irreversible transmural ischemia. At 30 days, the mortality rate was 20% and the primary patency was 92%. Ten patients underwent unplanned relaparotomy, of whom one needed resection of a large part of the small bowel. At 12 months, the mortality rate was still 20%. The primary patency was 83%. Primary assisted patency was 91%, and secondary patency was 100%. Clinical success at 30 days, 6 months, and 12 months, respectively, was 73%, 67%, and 67%.

CONCLUSIONS

AMI is still a devastating event. If PMAS is not feasible, ROMS is a reliable alternative and is associated with a relatively low mortality and morbidity rate.

Mesenteric stenosis, collaterals, and compensatory blood flow

BACKGROUND

The mesenteric circulation has an extensive collateral network. Therefore, stenosis in one or more mesenteric arteries does not necessarily lead to symptoms. The objective of this study was to determine the effect of collateral flow on celiac artery (CA) and superior mesenteric artery (SMA) duplex parameters.

METHODS

Between 1999 and 2007, a cohort of 228 patients analyzed for suspected chronic mesenteric syndrome was studied. Stenosis of the mesenteric vessels and collateral flow patterns were identified on angiography and categorized. The effect of stenosis in one mesenteric vessel and the presence of collaterals from the other unaffected vessel was examined in both the CA and SMA.

RESULTS

Stenosis of the CA resulted in a significantly higher peak systolic velocity (PSV) and end-diastolic velocity in the normal SMA without stenosis. This was also found for the CA without stenosis in the presence of a stenosis of the SMA. An incremental effect of the severity of the CA stenosis was found with a mean SMA PSV of 158 cm/s when normal and 259 cm/s when occluded. The presence of collaterals had a clear effect on duplex parameters of the angiographically normal SMA. In the presence of collaterals and a 70% CA stenosis, the PSV in the normal SMA was significantly higher (P = .025).

CONCLUSIONS

This study shows that stenosis in either the CA or SMA increases flow velocities in the other unaffected mesenteric artery. This increase was correlated with the presence of collaterals. Collaterals and stenoses in one of the mesenteric arteries may lead to mimicking or overgrading of stenosis in the other mesenteric artery.

[From CVA or TIA to carotid surgery: the clinical treatment course for patients with symptomatic carotid disease could be shorter]

OBJECTIVE

To gain insight into the duration and the various components of the clinical treatment course for patients with symptomatic carotid artery stenosis, in order to improve the care provided to these patients.

DESIGN

Retrospective cohort study.

METHODS

All patients who had undergone a carotid intervention for significant symptomatic carotid stenosis from 2001 to 2011 were included. Quantile regression analysis was used to assess the changes which had occurred in the median duration of the period from neurological event to intervention from 2001 onward. In order to chart the clinical treatment course, it was split up in different components. In addition, the impact of the referrer and the relationship between the time of the intervention and the risk of perioperative complications were also evaluated.

RESULTS

The median duration of the entire clinical treatment course decreased during the study period from 79 days (interquartile range (IQR): 59-113) in the reference period 2001-2004 to 19 days (IQR: 13-28) in 2011. All components of the clinical pathway had contributed to this decline. The duration of the clinical course in patients who had been externally referred was more than 3 times longer (median 67 vs. 21 days, p < 0.01). The total duration of the process did not affect the number of perioperative complications.

CONCLUSION

In the last decennium, the duration of the clinical treatment course of care in patients with symptomatic carotid artery disease was greatly reduced. Analyses of the processes which make up the chain of events, however, reveal that there is still much to be gained in the period before initial presentation at the hospital for patients who are referred by their general practitioners as well as those referred by other hospitals.

Splanchnic artery stenosis and abdominal complaints: clinical history is of limited value in detection of gastrointestinal ischemia

Background

Splanchnic artery stenosis is common and mostly asymptomatic and may lead to gastrointestinal ischemia (chronic splanchnic syndrome, CSS). This study was designed to assess risk factors for CSS in the medical history of patients with splanchnic artery stenosis and whether these risk factors can be used to identify patients with high and low risk of CSS.

Methods

All patients referred for suspected CSS underwent a standardized workup, including a medical history with questionnaire, duplex ultrasound, gastrointestinal tonometry, and angiography. Definitive diagnosis and treatment advice was made in a multidisciplinary team. Patients with confirmed CSS were compared with no-CSS patients.

Results

A total of 270 patients (102 M, 168 F; mean age, 53 years) with splanchnic artery stenosis were analyzed, of whom 109 (40%) had CSS and 161 no CSS. CSS-patients more often reported postprandial pain (87% vs. 72%, p = 0.007), weight loss (85% vs. 70%, p = 0.006), adapted eating pattern (90% vs. 79%, p = 0.005) and diarrhea (35% vs. 22%, p = 0.023). If none of these risk factors were present, the probability of CSS was 13%; if all were present, the probability was 60%. Adapted eating pattern (odds ratio (OR) 3.1; 95% confidence interval (CI) 1.08–8.88) and diarrhea (OR 2.6; 95% CI 1.31–5.3) were statistically significant in multivariate analysis.

Conclusions

In patients with splanchnic artery stenosis, the clinical history is of limited value for detection of CSS. A diagnostic test to detect ischemia is indispensable for proper selection of patients with splanchnic artery stenosis who might benefit from treatment.

Endovascular treatment of ruptured abdominal aortic aneurysm: is there a long-term benefit at follow-up?

AIM

Several studies have shown the feasibility of endovascular repair of ruptured abdominal aortic aneurysms (rEVAR). However, the role and value of rEVAR remains controversial due to selection bias and lack of long-term results. In the present study we describe our short- and long-term results of treating patients with rEVAR irrespective of hemodynamic condition and challenging anatomy.

METHODS

In April 2006 we started the single centre prospective non-randomised Ruptured Aneurysm Study (RASA). During a four year enrolment period all consecutive patients presenting with infrarenal ruptured AAA (rAAA, N.=117) were assessed for preferential rEVAR treatment. A rAAA was defined as extravasation of blood or hematoma outside the AAA due to transmural tear in the infrarenal abdominal aorta wall documented by preoperative computed tomography (CT) angiography examination or during open repair. Patients with challenging anatomy (infrarenal neck length below 15 mm and neck angulation above 60 degrees) were included as part of a damage control concept. Complication and mortality rates were studied at 30 days and yearly afterwards.

RESULTS

Thirty-five patients (33% of all admitted rAAA) were treated with rEVAR and 42% of them were considered hemodynamically unstable (systolic blood pressure <100 mmHg) and 30% had challenging AAA anatomy. The mortality rate at 30 days in the rEVAR group was 17%, in the open repair group 31%, and in the entire rAAA group (including abstained patients) 36%. During the first 30 days, 18 rEVAR patients experienced complications with nine re-interventions as a result. Long-term mortality of the rEVAR patients was 34% after a median follow-up of 3.4 years. All deaths after one year follow-up were non-AAA related. Multivariate analysis shows that Hardman index, presence of peripheral arterial obstructive disease and lowest systolic blood pressure during surgery are independently associated with long-term survival. Challenging rAAA anatomy was not associated with impaired survival.

CONCLUSION

Our study shows that rEVAR is feasible irrespective of hemodynamic condition and that it is associated with relative low mortality rates. Challenging rAAA anatomy may not affect overall long-term survival, but six out of ten patients remain unsuitable for rEVAR because of inappropriate anatomy.

Medical treatment in carotid artery intervention

Medical treatment has a pivotal role in the treatment of patients with occlusive carotid artery disease. Large trials have provided the justification for operative treatment besides medical treatment in patients with recent significant carotid artery stenosis two decades ago. Since then, medical therapy has evolved tremendously. Next to aspirin, antiplatelet regimens acting on a different level in the modulation of platelet aggregation have made their entry. Moreover, statin therapy has been introduced. These changes among others in secondary stroke prevention, along with better understanding in life-style adjustments and perioperative medical management, have led to a decrease in stroke recurrence. Secondary prevention is therefore now the most important pillar of medical therapy. It consists of antiplatelet therapy, statins and blood pressure lowering agents in all patients. Small adjustments are recommended for those patients referred for invasive treatment. Moreover, long-term medical treatment is imperative. In this article, we summarize current evidence in literature regarding medical management in patients with previous stroke or TIA.

[Endarterectomy more favourable than stenting in symptomatic significant carotid stenosis: higher risk of ischaemic stroke or death following stenting]

Carotid endarterectomy (CEA) has proven its value in the treatment of patients with recent significant carotid artery stenosis. Percutaneous transluminal angioplasty with carotid artery stenting ('stenting' in short) is an alternative to CEA. The results of stenting and CEA in patients with symptomatic significant carotid artery stenosis were evaluated in 9 prospective randomized controlled trials and 11 meta-analyses. Almost all of these trials failed to show superiority of stenting to CEA. According to the 4 largest and most recent studies in this field the risk of a stroke or death within 30 days after the intervention is considerably higher following stenting than following CEA. In the long run the results of stenting and CEA seem to be comparable. CEA remains the gold standard in treatment of significant carotid artery stenosis, in particular in patients older than 70.

Open or percutaneous revascularization for chronic splanchnic syndrome

BACKGROUND

Treatment of chronic splanchnic syndrome remains controversial. In the past 10 years, endovascular repair (ER) has replaced open repair (OR) to some extent. This evidence summary reviews the available evidence for ER or OR of chronic splanchnic syndrome.

METHODS

A systematic literature search of MEDLINE database was performed to identify all studies that evaluated treatment of chronic splanchnic syndrome between 1988 and 2009.

RESULTS

The best available evidence consists of prospectively accumulated but retrospectively analyzed data with a high risk for confounding. Only a few of these studies incorporated functional tests to assess splanchnic ischemia before or after treatment. ER has the advantage of low short-term morbidity but the disadvantage of decreased long-term primary patency compared with OR. ER and OR have similar rates of secondary patency, although the reintervention rate after ER is higher.

CONCLUSION

ER appears to be preferential in the treatment of elderly patients and in patients with comorbidity, severe cachexia, or hostile abdomen. Long-term results after OR are excellent. OR can still be proposed as the preferred option for relatively young and fit patients.

Association of the TGF-beta receptor genes with abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a multifactorial condition. The transforming growth factor beta (TGF-beta) pathway regulates vascular remodeling and mutations in its receptor genes, TGFBR1 and TGFBR2, cause syndromes with thoracic aortic aneurysm (TAA). The TGF-beta pathway may be involved in aneurysm development in general. We performed an association study by analyzing all the common genetic variants in TGFBR1 and TGFBR2 using tag single nucleotide polymorphisms (SNPs) in a Dutch AAA case-control population in a two-stage genotyping approach. In stage 1, analyzing 376 cases and 648 controls, three of the four TGFBR1 SNPs and nine of the 28 TGFBR2 SNPs had a P<0.07. Genotyping of these SNPs in an independent cohort of 360 cases and 376 controls in stage 2 confirmed association (P<0.05) for the same allele of one SNP in TGFBR1 and two SNPs in TGFBR2. Joint analysis of the 736 cases and 1024 controls showed statistically significant associations of these SNPs, which sustained after proper correction for multiple testing (TGFBR1 rs1626340 OR 1.32 95% CI 1.11-1.56 P=0.001 and TGFBR2 rs1036095 OR 1.32 95% CI 1.12-1.54 P=0.001 and rs4522809 OR 1.28 95% CI 1.12-1.46 P=0.0004). We conclude that genetic variations in TGFBR1 and TGFBR2 associate with AAA in the Dutch population. This suggests that AAA may develop partly by similar defects as TAA, which in the future may provide novel therapeutic options.

Retroperitoneal endoscopic release in the management of celiac artery compression syndrome

INTRODUCTION

Celiac artery compression syndrome (CACS) can be treated successfully by division of the median arcuate ligament and celiac plexus fibers. The standard technique is the open approach by an upper midline or left subcostal incision. Only six single cases in which a laparoscopic transabdominal approach for CACS was used have been reported. We prospectively evaluated the feasibility of the endoscopic retroperitoneal approach for treatment of CACS.

METHODS

All patients with symptoms suggestive of CACS were evaluated using splanchnic duplex ultrasound scanning, gastric exercise tonometry (GET), and multiplane selective splanchnic angiography. The criteria for treatment were chronic abdominal symptoms, respiratory-dependent CA stenosis, and abnormal GET result. The release was performed by a retroperitoneal endoscopic approach. Anatomic success of the procedure was confirmed by angiography.

RESULTS

The endoscopic retroperitoneal approach was used to treat 46 patients with CACS. One patient (2%) required conversion to an open procedure due to suprarenal artery bleeding. Release was ended prematurely in one patient due to a pneumothorax resulting in loss of working space. A postoperative pneumothorax developed in two patients, of which one needed treatment. No other complications were observed. Postoperative angiography during inspiration and expiration showed normal vessel anatomy in 36 of 46 patients. Six of 10 patients with persisting intraluminal stenoses were treated endovascularly. Five of these were successful, which brings the primary-assisted anatomic patency for the total group to 89% (41 of 46 patients). Three patients are being observed, and endovascular treatment remains an option in case of insufficient improvement. On median follow-up of 20 months (range, 2-42 months) 41 patients were free of symptoms or showed significant improvement.

CONCLUSIONS

The endoscopic retroperitoneal approach for the release of the CA in CACS, with additional endovascular treatment of persistent stenosis, is feasible and effective. Short-term results were comparable with the open procedure.

Clinical Approach to Chronic Gastrointestinal Ischaemia: From 'Intestinal Angina' to the Spectrum of Chronic Splanchnic Disease

Stenotic disorders of the splanchnic arteries are not rare, and it is generally assumed that symptoms are rare in patients with a single splanchnic stenosis, and even in patients with multiple-vessel stenoses. Currently, only gastric exercise tonometry aids the diagnostic evaluation, as it indicates actual ischaemia. Patients with stenotic disorders without complaints are referred to as having chronic splanchnic disease (CSD) and those with ischaemic complaints as having chronic splanchnic syndrome (CSS). The classical presentation of CSS, including the triad postprandial pain, weight loss and upper abdominal bruit, is also known as 'intestinal angina'. From the experience of our multidisciplinary working team on gastrointestinal ischaemia in 110 patients with stenoses of at least one splanchnic artery, two different clinical patterns were observed. In our series approximately 60% of patients with single-vessel stenoses, including the coeliac artery compression syndrome, have CSS. They have fewer complications, very low mortality, but most can be successfully treated by stenting or surgical treatment. Patients with multivessel splanchnic stenoses have more classical ischaemic complaints. Progression to a bowel infarction was seen in 34%, and mortality was 21%, mostly from bowel or myocardial infarction. Treatment should be tailored based upon perioperative risk assessment and local vascular anatomy. This may consist of autologous arterial bypass of one or two vessels, preferably antegrade. stenting or a combination of both. This differentiation between single- and multivessel splanchnic disease has considerable consequences for optimal work-up and treatment.

Doxycycline therapy for abdominal aneurysm: Improved proteolytic balance through reduced neutrophil content

BACKGROUND

Matrix metalloproteinase-9 (MMP-9) is thought to play a central role in abdominal aortic aneurysm (AAA) initiation. Doxycycline, a tetracycline analogue, has direct MMP-9-inhibiting properties in vitro, and it effectively suppresses AAA development in rodents. Observed inhibition of AAA progression, and contradictory findings in human studies evaluating the effect of doxycycline therapy on aortic wall MMP-9, suggest that the effects of doxycycline extend beyond MMP-9 inhibition and that the effect may be dose-dependent.

METHODS

This clinical trial evaluated the effect of 2 weeks of low- (50 mg/d), medium- (100 mg/d), or high-dose (300 mg/d) doxycycline vs no medication in four groups of 15 patients undergoing elective AAA repair. The effect of doxycycline treatment on MMP and cysteine proteases, and their respective inhibitors, was evaluated by quantitative polymerase chain reaction, Western blot analysis, immunocapture protease activity assays, and immunohistochemistry.

RESULTS

Doxycycline was well tolerated and no participants dropped out. Doxycycline treatment reduced aortic wall MMP-3 and MMP-25 messenger RNA expression (P < .045 and P < .014, respectively), selectively suppressed neutrophil collagenase and gelatinase (MMP-8 and MMP-9) protein levels (P < .013 and <.004, respectively), and increased protein levels of the protease inhibitors tissue inhibitor of metalloproteinase 1 and cystatin C (P < .029). As for the apparent selective effect on neutrophil-associated proteases, we sought for a reducing effect on aortic wall neutrophil content that was indeed confirmed by immunohistochemical analysis that revealed a 75% reduction in aneurysm wall neutrophil content (P < .001).

CONCLUSIONS

Independent of its dose, short-term preoperative doxycycline therapy improves the proteolytic balance in AAA, presumably through an effect on aortic wall neutrophil content. This study provides a rationale for doxycycline treatment in patients with an AAA as well as in other (vascular) conditions involving neutrophil influx such as Kawasaki disease and Behçet disease.

Diagnosis and management of splanchnic ischemia

Splanchnic or gastrointestinal ischemia is rare and randomized studies are absent. This review focuses on new developments in clinical presentation, diagnostic approaches, and treatments. Splanchnic ischemia can be caused by occlusions of arteries or veins and by physiological vasoconstriction during low-flow states. The prevalence of significant splanchnic arterial stenoses is high, but it remains mostly asymptomatic due to abundant collateral circulation. This is known as chronic splanchnic disease (CSD). Chronic splanchnic syndrome (CSS) occurs when ischemic symptoms develop. Ischemic symptoms are characterized by postprandial pain, fear of eating and weight loss. CSS is diagnosed by a test for actual ischemia. Recently, gastro-intestinal tonometry has been validated as a diagnostic test to detect splanchnic ischemia and to guide treatment. In single-vessel CSD, the complication rate is very low, but some patients have ischemic complaints, and can be treated successfully. In multi-vessel stenoses, the complication rate is considerable, while most have CSS and treatment should be strongly considered. CT and MR-based angiographic reconstruction techniques have emerged as alternatives for digital subtraction angiography for imaging of splanchnic vessels. Duplex ultrasound is still the first choice for screening purposes. The strengths and weaknesses of each modality will be discussed. CSS may be treated by minimally invasive endoscopic treatment of the celiac axis compression syndrome, endovascular antegrade stenting, or laparotomy-assisted retrograde endovascular recanalization and stenting. The treatment plan is highly individualized and is mainly based on precise vessel anatomy, body weight, co-morbidity and severity of ischemia.

[Gastrointestinal ischaemia during physical exertion as a cause of gastrointestinal symptoms]

Gastrointestinal (GI) symptoms are reported by up to 70% of endurance athletes. Although exercise leads to decreased gastrointestinal blood flow, GI-ischaemia is rarely reported as a cause. Mucosal ischaemia may result in nausea, abdominal cramps and bloody diarrhoea. After exercise, reperfusion damage and endotoxaemia may cause systemic symptoms as well. In three patients, two women aged 46 and 25 respectively and a man aged 40, with a heterogeneous presentation of exercise induced GI-symptoms, GI-ischaemia was demonstrated using gastric exercise tonometry. Gastric tonometry is mandatory for the diagnosis and follow-up. In the first patient, an isolated celiac artery stenosis was found; after incision of the left crus of the diaphragm, she was asymptomatic and the results of gastric tonometry improved. The other two patients had non-occlusive ischaemia associated with high exercise intensity. Reduction of the exercise intensity resulted in the complaints disappearing.

Acute stress-related gastrointestinal ischemia

We report a case of acute gastrointestinal ischemia during a very stressful event in whom the diagnosis was made by 24-hour tonometry. This case report unequivocally links a stressful event with increased catecholamine release and subsequent severe symptomatic gastrointestinal ischemia. The role of ischemia as potential pathophysiological mechanism has never been studied in detail. The clinical significance of finding such an association is underscored by this case report, where a vasoactive drug normally used for hypertension treatment resulted in greatly improved abdominal symptoms.

Twenty-four hour tonometry in patients suspected of chronic gastrointestinal ischemia

BACKGROUND AND AIMS

Gastrointestinal tonometry is currently the only clinical diagnostic test that enables identification of symptomatic chronic gastrointestinal ischemia. Gastric exercise tonometry has proven its value for detection of ischemia in this patients group, but has its disadvantages. Earlier studies with postprandial tonometry gave unreliable results. In this study we challenged (again) the use of postprandial tonometry in patients suspected of gastrointestinal ischemia.

METHODS

Patients suspected for chronic gastrointestinal ischemia had standard diagnostic work up, including gastric exercise tonometry and 24-h tonometry using standard meals.

RESULTS

Thirty-three patients were enrolled in the study. Chronic gastrointestinal ischemia was diagnosed in 17 (52%) patients. The 24-h tonometry correctly predicted the presence of ischemia in 13/17 patients, and absence of ischemia in 15/16 patients.

CONCLUSIONS

The use of 24-h tonometry after meals in patients suspected of gastrointestinal ischemia seems feasible, with promising accuracy for the detection of ischemia.

What is the best diagnostic approach for chronic gastrointestinal ischemia?

BACKGROUND

Chronic gastrointestinal ischemia is still a difficult diagnosis to establish. The diagnosis depends on a high degree of clinical suspicion as well as selective angiography. Duplex sonography may serve as a screening tool, providing information on splanchnic vessel patency and flow patterns. GET is a minimally invasive test that can be used for diagnosis in patients with chronic gastrointestinal ischemia, and can differentiate between symptomatic and asymptomatic splanchnic artery stenosis. In the present study, we compared four different diagnostic approaches.

METHODS

Between 1997 and 2000, 84 patients were evaluated for suspected chronic gastrointestinal ischemia. All underwent splanchnic arterial angiography, duplex sonography, and GET. For the presence or absence of stenosis, angiography was used as the gold standard. For diagnosing ischemia, we relied on a panel decision. The diagnostic approaches studied were: (a) angiography, only in patients with classic abdominal angina; (b) screening with duplex sonography, angiography if sonography abnormal or unreliable; (c) screening with gastric tonometry and angiography if tonometry not normal; (d) both gastric tonometry exercise and duplex sonography, angiography if one of both screening tests not normal.

RESULTS

In 28 patients, chronic gastrointestinal ischemia was diagnosed. Using clinical suspicion only, 16 patients (57%) would have been missed. Screening by duplex sonography or gastric tonometry only would have missed 4 or 6 patients, respectively. Screening with combined gastric tonometry and duplex sonography would not have missed patients with symptomatic ischemia, while 21% of angiographies would have been avoided.

CONCLUSION

Screening by combined GET and duplex sonography has excellent diagnostic accuracy. Currently, this approach represents the best diagnostic workup strategy in patients with suspected chronic gastrointestinal ischemia.

Triggering for submaximal exercise level in gastric exercise tonometry: serial lactate, heart rate, or respiratory quotient?

Gastric exercise tonometry is a functional diagnostic test in chronic gastrointestinal ischemia. As maximal exercise can cause false-positive tests, exercise buildup should be controlled to remain submaximal. We evaluated three parameters for monitoring and adjusting exercise levels (heart rate [HR], respiratory quotient [RQ], and serial lactate measurements) in 178 tests in both healthy volunteers and patients suspected of gastrointestinal ischemia. Exercise levels above submaximal occurred in 20% of HR-, 2% of RQ-, and 5% of lactate-monitored tests (P<0.05 for HR vs. RQ and lactate). Low levels were seen in 5% of HR-, 10% of RQ-, and 41% of lactate-monitored tests (P<0.01 for lactate vs. HR and RQ). High levels resulted in 43% false-positive tonometry results compared to 19% of all tests (P<0.001); low levels did not result in more false negatives (5% vs. 6%). Although RQ monitoring yielded the greatest proportion of optimal exercise tests, serial lactate monitoring is our method of choice, combining optimal diagnostic accuracy, low cost, and simplicity.

Clinical significance of splanchnic artery stenosis

BACKGROUND

The clinical relevance of splanchnic artery stenosis is often unclear. Gastric exercise tonometry enables the identification of patients with actual gastrointestinal ischaemia. A large group of patients with splanchnic artery stenosis was studied using standard investigations, including tonometry.

METHODS

Patients referred with possible intestinal ischaemia were analysed prospectively, using duplex imaging, conventional abdominal angiography and tonometry. All results were discussed within a multidisciplinary team.

RESULTS

Splanchnic stenoses were found in 157 (49.7 percent) of 316 patients; 95 patients (60.5 percent) had one-vessel, 54 (34.4 percent) two-vessel and eight (5.1 percent) had three-vessel disease. Chronic splanchnic syndrome was diagnosed in 107 patients (68.2 percent), 54 (57 percent) with single-vessel, 45 (83 percent) with two-vessel and all eight with three-vessel stenoses. Treatment was undertaken in 95 patients, 62 by surgery and 33 by endovascular techniques. After a median follow-up of 43 months, 84 percent of patients were symptom free.

CONCLUSION

Gastric exercise tonometry proved crucial in the evaluation of possible intestinal ischaemia. Comparing patients with single- and multiple-vessel stenoses, there were significant differences in clinical presentation and mortality rates.

Effect of various test meals on gastric and jejunal carbon dioxide: A study in healthy subjects

OBJECTIVE

The normal pattern of carbon dioxide (CO2) levels in the human stomach and small bowel after meals is unknown. The intraluminal carbon dioxide level is a sensitive and early marker for organ mucosal ischemia. CO2 levels in both the stomach and small bowel are influenced by multiple factors other than adequacy of perfusion. Gastric acid production, salivary bicarbonate and CO2 produced or absorbed by meals are the disturbing variables. Prolonged gastric (and jejunal) tonometry after meals can be of additional value in the work-up of patients suspected of (chronic) gastrointestinal ischemia. The purpose of this study was to challenge these problems using in vitro tested meals and a rigid acid-suppression regimen in a group of healthy subjects.

MATERIAL AND METHODS

Standard meals were tested in vitro on the ability to produce and buffer CO2. Meals with the least CO2 variations were subsequently used in healthy subjects. Tonometry of the stomach and jejunum was performed for 24 h, with optimal and controlled acid suppression.

RESULTS

Ten subjects were enrolled in the study. Acid production was sufficiently suppressed. The gastric PCO2 baseline (fasting) was 6.5 (1.0), and significantly lower than the jejunum PCO2 baseline of 7.6 (0.9) kPa. The gastric baseline during the day was 6.9 (1.6), and significantly lower than the gastric baseline during the night of 8.0 (1.8), suggesting a diurnal variation of PCO2. Increases in PCO2 levels were seen in all subjects, after meals and between meals.

CONCLUSIONS

Prolonged gastric and jejunal tonometry is feasible in humans. PCO2 levels were seen to peak after, but also in-between, most meals. The diurnal variation in PCO2 might reflect reversible gastric mucosal ischemia.

Gastric exercise tonometry: the key investigation in patients with suspected celiac artery compression syndrome

INTRODUCTION

Controversy continues about the mere existence of the celiac artery compression syndrome. Earlier results of treatment of unselected patients groups showed varying, mostly disappointing, results. The recently introduced gastric exercise tonometry test is able to identify patients with actual gastrointestinal ischemia. We prospectively studied the use of gastric exercise tonometry as a key criterion for revascularization treatment in patients with otherwise unexplained abdominal complaints and significant stenosis of the celiac artery by compression of the arcuate ligament.

METHODS

Patients were prospectively selected using abdominal artery angiography and gastric exercise tonometry. Patients with a significant compression of the celiac artery, typical abdominal complaints, and abnormal tonometry were considered for revascularization.

RESULTS

Over a 7-year period, 43 patients with significant celiac artery compression were included in this study, and 30 patients were diagnosed as ischemic. Twenty-nine patients had revascularization, 22 (76 %) had a trunk release only. After a median follow-up of 39 months, 83% of patients were free of symptoms. The repeated tonometry after treatment improved in 100% of patients free of symptoms, compared with 25% in patients with persistent complaints after revascularization.

CONCLUSIONS

The results of this study suggest that the celiac axis compression syndrome exists and that the actual ischemia can be detected by gastric exercise tonometry and treated safely, with success.

Implant Degradation and Poor Healing After Endovascular Repair of Abdominal Aortic Aneurysms: An Analysis of Explanted Stent-Grafts

PURPOSE

To study explanted stent-grafts to achieve a better understanding of the mechanisms of failure after endovascular treatment of abdominal aortic aneurysms (AAA).

METHODS

Twelve stent-grafts were harvested at autopsy (n=3) or during surgical conversion (n=9). Device alterations were investigated by macroscopic examination, radiography, and surface analysis techniques. Healing around the implants was studied via histology and immunohistochemistry, with particular attention to the stent-graft/tissue interface.

RESULTS

Degradation was more important with Vanguard stent-grafts (off the market) than with AneuRx and Talent stent-grafts, but rupture of nitinol wires and poor surface finish in Talent stent-grafts raise concern about their corrosion resistance and long-term stability. Poor healing was observed around stent-grafts even after several years of implantation, with absence of vascular smooth muscle cells, fibroblasts, and collagen formation. In addition to the well-known foreign body reaction around the graft, numerous polymorphonuclear cells characteristic of the first step of healing were present in tissues around stent-grafts retrieved at surgical conversion. Factors explaining the lack of tissue organization around stent-grafts are discussed.

CONCLUSION

The long-term stability of implants remains a concern and requires more transparency from manufacturers regarding the surface properties of their devices. Lack of neointima formation impairs biological fixation of the implant to the vessel wall, leading to possible endoleaks and migration. New-generation stent-grafts promoting biological fixation should be developed to improve clinical outcomes of this minimally invasive treatment.

Endograft treatment of ruptured abdominal aortic aneurysms using the Talent aortouniiliac system: An international multicenter study

OBJECTIVE

To understand the potential of endovascular aneurysm repair (EVAR) in patients presenting with a ruptured abdominal aortic aneurysm (rAAA), the proportion in whom this procedure was applicable was assessed. Mortality and morbidity was also determined in patients treated with emergency EVAR (eEVAR) when anatomic and hemodynamic conditions allowed (ie, in the entire cohort with patients receiving endovascular and open repair combined). In addition, a comparison was made between the treatment group with eEVAR and open repair.

METHODS

Between February 2003 and September 2004, 10 participating institutions enrolled a representative sample of 100 consecutive patients in whom eEVAR was considered. Patients in the New Endograft treatment in Ruptured abdominal aortic Aneurysm (ERA) trial were offered eEVAR or open repair in accordance with their clinical condition or anatomic configuration. Written informed consent was obtained from all patients or their legal representatives. The study included patients who were treated by stent-graft technique or by open surgery in the case of adverse anatomy for endoluminal stent-grafting or severe hemodynamic instability, or both. Data were collated in a centralized database for analysis. The study was sponsored and supported by Medtronic, and eEVAR was uniquely performed with a Talent aortouniiliac (AUI) system in all patients. Crude and adjusted 30-day or in-hospital and 3-month mortality rates were assessed for the entire group as a whole and the EVAR and open repair category separately. Complication rates were also assessed.

RESULTS

Stent-graft repair was performed in 49 patients and open surgery in 51. No significant differences were observed between these treatment groups with regard to comorbidity at presentation, hemodynamic instability, and the proportion of patients who could be assessed by preoperative computed tomography scanning. Patients with eEVAR more frequently demonstrated a suitable infrarenal neck for endovascular repair, a longer infrarenal neck, and suitable iliac arteries for access than patients with open repair. The primary reason to perform open aneurysm repair was an unfavorable configuration of the neck in 80% of the patients. In patients undergoing eEVAR, operative blood loss was less, intensive care admission time was shorter, and the duration of mechanical ventilation was shorter (P < or = .02, all comparisons). The 30-day or in-hospital mortality was 35% in the eEVAR category, 39% in patients with open repair, and 37% overall. There was no statistically significant difference between the treatment groups with regard to crude mortality rates or rates adjusted for age, gender, hemodynamic shock, and pre-existent pulmonary disease. The cumulative 3-month all-cause mortality was 40% in the eEVAR group and 42% in the open repair group (no significant differences at crude and adjusted comparisons). The 3-month primary complication rate in the two treatment groups was similar at 59%.

CONCLUSIONS

In approximately half the rAAA patients, eEVAR appeared viable. An unsuitable infrarenal neck was the most frequent cause to select open repair. In dedicated centers using a Talent AUI system, eEVAR appeared to be a feasible method for treatment of a rAAA. The overall first-month mortality did not differ across treatment groups (patients with endovascular and open repair combined), yet was somewhat lower than observed in a recent meta-analysis reporting on open repair.

Consistency in endovascular aneurysm repair suitability assessment requires group decision audit

INTRODUCTION

Proper selection of patient and stent-graft combinations in endovascular aneurysm repair (EVAR) depends on knowledge and experience with the different types of stents that have to be adapted to the patient's unique abdominal aortoiliac anatomy. The aim of this study was to analyze the consistency and variance in EVAR suitability assessment between clinicians.

METHODS

Worksheets that contained anatomic data derived from computed tomography scans and angiography were compiled for 202 patients. Five clinicians, all experienced in EVAR surgery, assessed the anatomic data on the worksheets for suitability for three types of stent-grafts. The obtained 3030 assessments represented a quantification of the likelihood of success the clinician expected for effective and durable sealing and fixation of the stent-graft in EVAR. The Delphi method was used to determine consensus in the thinking process among clinicians, and kappa analysis was used to determine the proportion of variances in the assessment result between clinicians.

RESULTS

With the Delphi method, Cronbach alpha values of 0.87, 0.87, and 0.90 were reached for the three types of stent-grafts in the second assessment round. The individual clinician-group correlation in round two was between 0.69 and 0.86 for clinicians 1, 2, 3, and 4. Between clinician 5 and the others, correlation varied between 0.43 and 0.64. The kappa values ranged between 0.32 and 0.51 among clinicians 1, 2, and 3. Between clinician 5 and the others, kappa values between 0.08 and 0.29 were reached.

CONCLUSION

EVAR suitability estimation in a cohort of patients is highly consistent in a group of experienced clinicians. The EVAR suitability estimation at the individual patient level varies substantially between clinicians, however. Aggregating expert opinions in abdominal aortic aneurysm anatomic suitability assessment for EVAR had the opportunity to replace individual clinician decision diversification in a more solid and consistent group decision process.

Validation of open-surgery VR trainer

VREST (Virtual Reality Educational Surgical Tools) is developing a universal and autonomous simulation platform which can be used for training and assessment of medical students and for continuing education of physicians. With the VREST - Virtual Lichtenstein Trainer, simulating the open surgery procedure of the inguinal hernia repair according to Lichtenstein, the validation of the simulator is ongoing. Part of this trajectory is the evaluation of the transfer of training of the virtual incision making. One group of students trained incision making on the VREST platform where the control group did not. In an experiment both groups has to perform several incision tasks on a manikin. The results are not available yet but will be presented at the MMVR14 conference.

Open surgery in VR: inguinal hernia repair according to Lichtenstein

VREST (Virtual Reality Educational Surgical Tools) is developing a universal and autonomous simulation platform which can be used for training and assessment of medical students and for continuing education of physicians. A workstation consisting of two haptic devices and a 3D vision system is part of the VREST platform. Another part of the platform is a generic software environment in which lessons can be built by the teacher and performed by their students. Using the platform one can see, feel and decide as in reality. With the assessment tool the progress and skills of the students can be supervised. The first lesson build on the VREST platform is an inguinal hernia repair according to Lichtenstein. This is an open surgery procedure. The VREST platform is used prior to the first operating room surgery of the resident. Interactive models and case dependent feedback is used to enlarge the residents' cognition. This should reduce the training time in the operating room.

Analysis of the Balance between Proliferation and Apoptosis of Cultured Vascular Smooth Muscle Cells for Tissue- Engineering Applications

Tissue homeostasis, the balance between cell proliferation and apoptosis, is an important factor in tissue engineering. We describe a new method to analyze markers of both proliferation and apoptosis in a single assay to monitor growth behavior of cell cultures. Human vascular smooth muscle cells (VSMCs) were cultured either on gelatin-coated tissue culture polystyrene or in three-dimensional porous scaffolds composed of insoluble collagen and elastin. mRNA concentrations of cyclin E, as a marker of proliferation, and of tissue transglutaminase (tTG) as a marker of apoptosis, quantified by a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and normalized to porphobilinogen deaminase mRNA concentrations, were analyzed. tTG mRNA expression levels were increased when apoptosis was induced by tumor necrosis factor-alpha in combination with cycloheximide or by culturing the cells in serum-free culture medium. Cyclin E mRNA expression levels were less altered in these cell cultures. Results were compared with several reference tests to measure apoptosis including DNA fragmentation, annexin V staining, and light microscopy. This RT-PCR method could be used to characterize cell growth behavior of VSMCs in vitro. In addition, it was shown that this test is suitable to measure the balance between proliferation and apoptosis of VSMCs present in tissue-engineered constructs.

Clinical impact of gastric exercise tonometry on diagnosis and management of chronic gastrointestinal ischemia

BACKGROUND & AIMS

Chronic gastrointestinal ischemia or chronic splanchnic syndrome is a difficult diagnosis. The use of a physiologic test, combined with clinical and anatomic data, should improve diagnostic accuracy. This study evaluates the diagnostic accuracy and clinical impact of gastric tonometry during exercise (GET) in a patient cohort suspected of chronic splanchnic syndrome.

METHODS

From 1997 to 2000, 102 patients with chronic abdominal pain were analyzed. The workup included GET and selective biplane angiography. The diagnosis of gastrointestinal ischemia was based on consensus in a multidisciplinary working group and sustained on follow-up.

RESULTS

Gastrointestinal ischemia was diagnosed in 38 patients. In 33 patients chronic splanchnic syndrome was found, with single vessel involvement in 20 (17 celiac artery, 3 mesenteric superior) and multivessel disease in 13. In 5 patients nonocclusive ischemia was found. By using receiver operator curve analysis, the difference between gastric and arterial partial pressure of carbon dioxide (PCO2 gradient) proved to be the best GET parameter. The criteria for diagnosing ischemia in GET were Pco2 gradient > 0.8 kPa and increase gastric PCO2, with base excess decrease <8 mmol/L during exercise. GET had 78% sensitivity and 92% specificity. Twenty-five patients underwent vascular treatment (19 operative, 6 stent/percutaneous transluminal angioplasty). After 4 years of follow-up 83% of patients were alive and free of symptoms.

CONCLUSIONS

GET is an accurate diagnostic tool to show gastrointestinal ischemia. Including GET into clinical decision making enabled selecting patients with ischemia, who benefited from vascular and medical treatment. These benefits were sustained during 4-year follow-up. GET should be considered in the workup of patients with a suspected diagnosis, of gastrointestinal ischemia.

The VREST learning environment

The VREST learning environment is an integrated architecture to improve the education of health care professionals. It is a combination of a learning, content and assessment management system based on virtual reality. The generic architecture is now being build and tested around the Lichtenstein protocol for hernia inguinalis repair.

Randomized clinical trial of continuous sutures or non-penetrating clips for radiocephalic arteriovenous fistula

Background

Despite several modifications to the original design, patency rates of radiocephalic arteriovenous fistulas have changed little since the first report in 1966. The use of non-penetrating clips for vascular anastomosis on the outcome of such fistulas was studied.

Methods

Between January 2000 and August 2003, 107 primary radiocephalic fistulas were constructed in 98 patients. The vascular anastomoses were performed at random with either sutures (n = 56) or clips (n = 51).

Results

Although there were trends for better primary and primary assisted patency of clipped fistulas, the differences were not statistically significant. The 6-month primary patency rate was 61 per cent with sutures and 69 per cent with clips (P = 0·393). The mean(s.d.) primary patency was 315(306) and 285(285) days for clipped and sutured fistulas respectively. With regard to secondary patency, clipped fistulas were better (P = 0·009). The mean(s.d.) secondary patency was 435(376) and 344(316) days for clipped and sutured fistulas, respectively. There were no significant differences in flow characteristics, number of revisions or other morbidity.

Conclusion

This randomized clinical trial provided further evidence that the use of vascular clips may improve the patency rate of radiocephalic arteriovenous fistulas for haemodialysis.

Endovascular Treatment of Chronic Splanchnic Syndrome

OBJECTIVE

The technical and clinical outcome of endovascular revascularization was analyzed in patients with suspicion of chronic splanchnic syndrome (CSS).

METHODS

Medical history, duplex, angiography and exercise gastric tonometry suggested CSS in 97 patients. Twenty-seven of them were treated endovascular (one patient had 3-vessel, 12 patients had 2-vessels, 14 patients had 1-vessel CSS). Five patients received previous splanchnic revascularization. Twenty-three patients (85%) had severe co-morbidity: cardiac, pulmonary or cachexia. Endovascular treatment consisted of percutaneous transluminal angiography (PTA) of the coeliac artery (CA) or superior mesenteric artery (SMA) in three and primary balloon expandable stenting in 24 patients (13 CA and 10 SMA solitary, two CA and SMA both, 31 splanchnic arteries in total).

RESULTS

Three patients showed procedure related complications (11%). Mean follow-up was 19, range 2-76 months. Two patients died during follow up, both not procedure or CSS related. Five patients had no improvement of symptoms, without evidence of re- or residual stenosis. The primary clinical success was 67%, secondary clinical success was 81%. The primary patency was 81% and secondary patency was 100%.

CONCLUSION

Endovascular treatment of CSS has a reasonable outcome. It is an alternative to operative treatment, especially in patients with high co-morbidity or limited life expectancy.

Effects of transfusion with red cells filtered to remove leucocytes: randomised controlled trial in patients undergoing major surgery

OBJECTIVE

To compare postoperative complications in patients undergoing major surgery who received non-filtered or filtered red blood cell transfusions.

DESIGN

Prospective, randomised, double blinded trial.

SETTING

19 hospitals throughout the Netherlands (three university; 10 clinical; six general).

PARTICIPANTS

1051 evaluable patients: 79 patients with ruptured aneurysm, 412 patients undergoing elective surgery for aneurysm, and 560 undergoing gastrointestinal surgery.

INTERVENTIONS

The non-filtered products had the buffy coat removed and were plasma reduced. The filtered products had the buffy coat removed, were plasma reduced, and filtered before storage to remove leucocytes.

MAIN OUTCOME MEASURES

Mortality and duration of stay in intensive care. Secondary end points were occurrence of multi-organ failure, infections, and length of hospital stay.

RESULTS

No significant differences were found in mortality (odds ratio for filtered v non-filtered 0.80, 95% confidence interval 0.53 to 1.21) and in mean stay in intensive care (- 0.4 day, - 1.6 to 0.6 day). In the filtered group the mean length of hospital stay was 2.4 days shorter (- 4.8 to 0.0 day; P = 0.050) and the incidence of multi-organ failure was 30% lower (odds ratio 0.70, 0.49 to 1.00; P = 0.050). There were no differences in rates of infection (0.98, 0.73 to 1.32).

CONCLUSION

The use of filtered transfusions in some types of major surgery may reduce the length of hospital stay and the incidence of postoperative multi-organ failure.

Outcome of abdominal aortic aneurysm repair in the era of endovascular treatment

Background

The effect on outcome of the introduction of endovascular techniques for the exclusion of abdominal aortic aneurysm (AAA) is largely unknown. The aim of the study was to contrast the early and mid-term outcome after open and endovascular AAA repair.

Methods

Consecutive patients who underwent transfemoral endovascular aneurysm repair (EVAR; n = 93) between April 1998 and January 2003, or conventional open aneurysm repair in the time intervals before (n = 113) and after (n = 82) the introduction of EVAR were studied. All data were collected prospectively. All patients underwent elective and primary repair. Patient survival was calculated by the Kaplan–Meier method and the possible predictive value of more than 25 perioperative variables on five outcome variables (length of intensive care unit stay, morbidity, and 30-day, 6-month and overall mortality) was assessed by multivariate analysis.

Results

There were no differences in risk profiles between the three groups. Selection for EVAR was based on anatomical grounds only. All five outcome variables were significantly better with EVAR than either former or recent open repair. The only significant predictors of failure were advanced age and the need to perform an additional procedure for former open repair; hypertension and the preoperative use of anticoagulants for recent open repair; and renal insufficiency and pulmonary insufficiency for EVAR.

Conclusion

EVAR offered considerable benefits compared with conventional open repair at early and mid-term follow-up, which was not explained by selection of patients with a favourable risk profile. In the current era, in which patients are selected for open repair as a consequence of unfavourable anatomy, morbidity and mortality rates following conventional open treatment of AAA have increased at early and mid-term, but not at long-term, follow-up.

Stereopsis in medical virtual-learning-environments

In surgical training a lot of effort is directed at developing virtual learning environments (VLE's). These environments usually include one or more of the following features: haptic feedback, the sending of a slightly different computer-generated image to both eyes (affording an user's experience of stereoptical depth), and a transparant interface that allows 'natural' interaction. Now that many of these VLE's are approaching a state of maturity, time has come to start evaluating these environments, as basic questions regarding the effectiveness of the features mentioned above remain unanswered. The purpose of this article is to present an experiment aimed at evaluating the effects of stereopsis during a learning phase on visuo-spatial reasoning in two subsequent tasks that are related to the medical practice of diagnosis.