Multicentre prospective study of fascial closure rate after open abdomen with vacuum and mesh-mediated fascial traction

BACKGROUND

Damage control surgery and temporary open abdomen (OA) have been adopted widely, in both trauma and non-trauma situations. Several techniques for temporary abdominal closure have been developed. The main objective of this study was to evaluate the fascial closure rate in patients after vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) for long-term OA treatment, and to describe complications.

METHODS

This prospective study included all patients who received VAWCM treatment between 2006 and 2009 at four hospitals. Patients with anticipated OA treatment for fewer than 5 days and those with non-midline incisions were excluded.

RESULTS

Among 151 patients treated with an OA, 111 received VAWCM treatment. Median age was 68 years. Median OA treatment time was 14 days. Main disease aetiologies were vascular (45 patients), visceral surgical disease (57) and trauma (9). The fascial closure rate was 76·6 per cent in intention-to-treat analysis and 89 per cent in per-protocol analysis. Eight patients developed an intestinal fistula, of whom seven had intestinal ischaemia. Intestinal fistula was an independent factor associated with failure of fascial closure (odds ratio (OR) 8·55, 95 per cent confidence interval 1·47 to 49·72; P = 0·017). The in-hospital mortality rate was 29·7 per cent. Age (OR 1·21, 1·02 to 1·43; P = 0·027) and failure of fascial closure (OR 44·50, 1·13 to 1748·52; P = 0·043) were independently associated with in-hospital mortality.

CONCLUSION

The VAWCM method provided a high fascial closure rate after long-term treatment of OA. Technique-related complications were few. No patient was left with a large planned ventral hernia.

Altered mRNA expression due to acute mesenteric ischaemia in a porcine model

INTRODUCTION

Messenger RNA (mRNA) changes in the small intestine in response to acute mesenteric ischaemia (AMI) could offer novel diagnostic possibilities, but have not been described. The aim was to characterize the mRNA response to experimental AMI.

MATERIALS AND METHODS

Twelve pigs underwent catheterisation of the superior mesenteric artery with injection of polivinylalcohol embolisation particles or sodium chloride. Laparotomy and intestinal tissue sampling were performed. Microarray analysis was performed using the GeneChip(®) whole porcine genome array.

RESULTS

Seven down-regulated cellular pathways were associated with protein, lipid and carbohydrate metabolism. Seventeen up-regulated pathways were associated with inflammatory and immunological activity, regulation of extracellular matrix and decreased cellular proliferation. Thrombospondin (THS), monocyte chemoattractant protein 1(MCP-1) and gap junction alpha 1(GJA-1) were consistently up-regulated in all embolised pigs. Genes encoding earlier proposed biomarkers for AMI were up-regulated, such as lactate dehydrogenase and creatine kinase, or down-regulated, such as intestinal fatty acid binding protein and glutathione S-transferase.

CONCLUSION

This study describes the intestinal tissue response on a gene expression level to AMI. THS, MCP-1 and GJA-1 were consistently up-regulated by ischaemia, whereas earlier proposed biomarkers for AMI were not. Gene expression may not be directly linked to the use of the corresponding proteins as potential clinical biomarkers.

Anisotropy tuning in tetragonal FeCo alloys

We review our previous work on magnetocrystalline anisotropy tuning of superlattices based on tetragonally distorted FeCo-alloys. In addition we present new experimental results on the effect of changing the composition of the FeCo alloy. The discussion is based on the separation of the magnetocrystalline anisotropy into contributions from the interfaces and strain, as well as from the composition.

Colonic ischaemia and intra-abdominal hypertension following open repair of ruptured abdominal aortic aneurysm

Background

The aim was to investigate the association between colonic ischaemia and intra-abdominal pressure (IAP) after surgery for ruptured abdominal aortic aneurysm (rAAA).

Methods

Sigmoid colon perfusion was monitored with an intramucosal pH (pHi) tonometer. Patients with a pHi of 7·1 or less were treated for suspected hypovolaemia with intravenous colloids and colonoscopy. IAP was measured every 4 h. Patients with an IAP of 20 mmHg or more had neuromuscular blockade, relaparotomy or both.

Results

A total of 52 consecutive patients had open rAAA repair; 30-day mortality was 27 per cent. Eight patients died shortly after surgery. Fifteen were not monitored for practical reasons; mortality in this group was 33 per cent. IAP and pHi were measured throughout the stay in intensive care in the remaining 29 patients. Monitoring led to volume resuscitation in 25 patients, neuromuscular blockade in 16, colonoscopy in 19 and relaparotomy in two. One patient died in this group. Twenty-three of 29 patients had a pHi of 7·1 or less, of whom 15 had a pHi of 6·9 or less. Sixteen had an IAP of 20 mmHg or more, of whom ten also had a pHi below 6·90. Peak IAP values correlated with the simultaneously measured pHi (r = –0·39, P = 0·003).

Conclusion

Raised IAP is an important mechanism behind colonic hypoperfusion after rAAA repair. Monitoring IAP and timely intervention may improve outcome.

Vacuum assisted wound closure in patients with lower extremity arterial disease. The experience from two tertiary referral-centres

AIM

The purpose of this investigation was to analyze predictors for wound healing, amputation and mortality after vacuum assisted closure (VAC) therapy of wounds in the lower limb in patients with arterial disease.

METHODS

One hundred and twenty one wounds were treated and followed for 12 months at two vascular centres in Uppsala and Malmö, Sweden. VAC therapy was applied in the wound at a topical negative pressure of 125 mmHg.

RESULTS

Median age of the patients was 74 years and critical lower limb ischemia was present in 87% of the patients at admission. Intestinal flora was cultivated in 74% of the wounds. VAC associated bleeding occurred in four patients. Complete wound healing was achieved in 66%. Deep groin infections were associated with synthetic graft infection (P<0.001), treatment outside hospital (P<0.001), faster healing (P<0.01) and lower amputation rate (P<0.005). Diabetes mellitus (OR 2.7; [95% CI 1.2-6.2]) and foot wound (OR 3.0; [95% CI 1.2-7.4]) were independent predictors for amputation. The absence of complete wound healing was the strongest factor for both amputation (P<0.001) and death (P<0.001).

CONCLUSIONS

VAC therapy of complex wounds in the lower limbs in patients with vascular disease was associated with high healing rates. Non-healed wounds after VAC therapy were predictors for amputation and death.

Popliteal artery aneurysm: epidemiology and modern management

PAA is a predominantly male disease, more than 90% of affected patients are men. Risk factors for amputation are poor run-off, use of a synthetic graft, emergency treatment and high age. The frequency of amputation decreased over time in Sweden, which was associated with increased use of preoperative thrombolysis and fasciotomy. Thrombolysis can transform an emergent into an elective situation, and often improves out-flow. The risk of late amputation is low. Operation with a Posterior approach is associated with lower risk of late expansion, and is considered first choice of treatment when a short by-pass is sufficient. Multiple aneurysm disease is common among patients with PAA, in particular among those with bilateral PAA. All patients, irrespective of age, should be included in a life-long surveillance program. Normal arterial segments should be re-examined after three years.

Invasive treatment for renovascular disease. A twenty year experience from a population based registry

AIM

To analyze time trends in invasive treatment of renovascular disease in one country.

METHODS

Data have been analyzed from registrations in the Swedish Vascular Registry.

RESULTS

Invasive treatment for renovascular disease contributes around 1% of all vascular surgery within the Swedish Vascular Registry. Over the twenty-year period 1987-2006 the population-based frequency of invasive treatment for renovascular disease has increased; 1 597 procedures have been registered with an increase over time. The age of the treated patients has increased over the period (P<0.001). There has been a shift from open to endovascular procedure and from isolated percutaneous transluminal renal angioplasty (PTRA) to PTRA combined with a stent. Complications and mortality are significantly higher in patients undergoing open reconstruction (P<0.01). One year follow-up is incomplete and long-term results are therefore not possible to evaluate through registry-data only.

CONCLUSION

Using nation-wide registry data it is possible to analyze time-trends also concerning rare diseases or interventions. The changing pattern toward endovascular treatment of renovascular disease is obvious. Follow-up data at one year are incomplete.

Graphene on Ru(0001): a 25 x 25 supercell

The structure of a single layer of graphene on Ru(0001) has been studied using surface x-ray diffraction. A surprising superstructure containing 1250 carbon atoms has been determined, whereby 25 x 25 graphene unit cells lie on 23 x 23 unit cells of Ru. Each supercell contains 2 x 2 crystallographically inequivalent subcells caused by corrugation. Strong intensity oscillations in the superstructure rods demonstrate that the Ru substrate is also significantly corrugated down to several monolayers and that the bonding between graphene and Ru is strong and cannot be caused by van der Waals bonds. Charge transfer from the Ru substrate to the graphene expands and weakens the C-C bonds, which helps accommodate the in-plane tensile stress. The elucidation of this superstructure provides important information in the potential application of graphene as a template for nanocluster arrays.

Time-trends in vascular access surgery in Sweden 1987-2006

OBJECTIVE

To study time-trends in vascular access surgery.

DESIGN

Prospectively registered data.

MATERIAL AND METHODS

The Swedish vascular registry (Swedvasc) was searched for haemodialysis access operations (HAO) 1987-2006.

RESULTS

12,342 open and endovascular operations were identified. Eighty-five percent of HAO 2004-2006 were reported to the registry. The median age of patients having their first HAO increased from 56 to 68 during the first decade (p<0.0001), then remained stable. The frequency of diabetes increased from 12% in 1987 to 32% in 2006 (p<0.0001). The percentage of first HAO of total workload decreased from 76% to 48%. The percentage of first HAO performed as vein fistulas remained unchanged. The number of patients recorded for ten or more previous HAO increased over time. Percutaneous angioplasties increased during the last decade. Of 4706 patients operated on with primary radiocephalic AV-fistulas, 2933 (62%) were operated only once. Analysis of 3739 subsequent operations in 1773 patients disclosed that at the tenth operation vein was still used in 54%. With an increasing number of operations, arterial inflow shifted towards a more proximal position.

CONCLUSIONS

Over time, the patients undergoing HAO became older and more often diabetic, reoperations increased. Despite these circumstances, vascular surgeons perform AV-fistulas without grafts in most patients.

Diagnostic accuracy of plasma biomarkers for intestinal ischaemia

OBJECTIVE

Intestinal ischaemia is a life-threatening condition with high mortality, and the lack of accurate and readily available diagnostic methods often results in delay in diagnosis and treatment. The aim of this study was to investigate the accuracy of different plasma biomarkers in diagnosing intestinal ischaemia.

MATERIAL AND METHODS

Prospective inclusion of patients older than 50 years with acute abdomen admitted to hospital in Karlskrona, Sweden, between 2001 and 2003. Venous blood was sampled prior to any surgery and within 24 h from onset of pain. D-lactate, alpha glutathione S-transferase, intestinal fatty acid binding protein, creatine kinase B, isoenzymes of lactate dehydrogenase (LD) and alkaline liver phosphatase (ALP) were analysed. D-dimer was analysed using four different commercially available test kits.

RESULTS

In-hospital mortalities among patients with (n = 10) and without (n = 61) intestinal ischaemia were 40 % and 3 %, respectively (p = 0.003). D-dimer was associated with intestinal ischaemia (p = 0.001) independently of which assay was used. No patient presenting with a normal D-dimer had intestinal ischaemia. D-dimer >0.9 mg/L had a specificity, sensitivity and accuracy of 82 %, 60 % and 79 %, respectively. Total LD, isoenzymes of LD 1-4 and liver isoenzyme of ALP (ALP liver) were significantly higher in patients with intestinal ischaemia, and accuracies for LD 2 (cut-off 2.3 microkat/L) and ALP liver (cut-off 0.7 microkat/L) were 69 % and 66 %, respectively.

CONCLUSIONS

D-dimer may be used as an exclusion test for intestinal ischaemia, but lacks specificity. The other plasma biomarkers studied had insufficient accuracy for this group of patients. Further studies are needed.

The Clinical Importance of Monitoring Intra Abdominal Pressure after Ruptured Abdominal Aortic Aneurysm Repair

Aim:

The aim of this paper was to review the literature on the clinical importance of monitoring intra-abdominal pressure (IAP) after ruptured abdominal aortic aneurysm (rAAA) repair.

Method:

The literature was searched for abdominal compartment syndrome (ACS) or intra-abdominal pressure and aortic aneurysm. Original articles were studied. Personal experiences were reported.

Results:

The consensus documents of the World society on the abdominal compartment syndrome ( wsacs.org ), with their definitions and guidelines, constitute an important step forward for the possibilities to study this clinical entity. Few papers were published describing the problem specifically in the patient population operated on for ruptured abdominal aortic aneurysm (rAAA). The incidence was approximately 5% when the patients were not monitored with IAP, and above 10% when IAP was monitored. The incidence seems to be similar irrespective if open or endovascular repair is performed, though comparative prospective studies were not published. Patients with intra-abdominal hypertension (IAH) or ACS have higher mortality and more complications. If IAH is recognized early conservative treatment may be effective to prevent development of ACS. After ACS has developed, surgical decompression is usually required. A proposed algorithm on how to act on different levels of IAH is presented.

Conclusions:

IAH/ACS is an important complication after operation on patients with rAAA. Monitoring IAP may be associated with improved outcomes.

The Value of a Nationwide Vascular Registry in Understanding Contemporary Time Trends of Abdominal Aortic Aneurysm Repair

Nationwide vascular registries offer rapid feed-back in an environment of fast new technical development, as is the case with the treatment of abdominal aortic aneurysm (AAA). Furthermore, they offer an opportunity to study non-selected, population-based data. The aim of this review was to analyze time-trends in published papers from nationwide registries on AAA-repair. In contrast to several US reports, an increased rate of intact AAA repair, associated with the introduction of endovascular repair, was reported in a recent publication based on the Swedish Vascular Registry (Swedvasc). The rate of ruptured abdominal aortic aneurysm (rAAA) repair is stable in most reports, while some report a decreasing incidence. Most nationwide studies report a reducing mortality over time after intact AAA repair, while time trends on the mortality after ruptured AAA repair are more heterogenic.

Risk of new aneurysms after surgery for popliteal artery aneurysm

Background

The risk of developing a new aneurysm after surgery for popliteal artery aneruysm (PAA) is not well known. The aim was to study this risk in a cohort of patients.

Methods

A total of 571 patients who had primary operation for PAA (717 legs) between 1987 and 2002 were identified from the Swedish Vascular Registry (Swedvasc). Of these, 190 patients were re-examined by ultrasonography after a median of 7 (range 2·9–18·7) years.

Results

The number of patients with at least one aneurysm in addition to the PAA was 108 (56·8 per cent) at the index operation and 131 (68·0 per cent) at re-examination. The overall number of aneurysms increased by 41·8 per cent, from 244 to 346. Among the 82 patients who had an isolated PAA at the index operation, 23 developed a new aneurysm; these patients tended to be older (P = 0·004). Bilateral PAA at the index operation was associated with a later development of abdominal aortic aneurysm (P = 0·004). Age (P = 0·004) and hypertension (P = 0·012) at the time of the index operation were associated with multianeurysm disease at any time. Six (4·3 per cent) of 138 legs treated by venous bypass grafts had developed a graft aneurysm by the time of re-examination. No normal arterial segment developed an aneurysm that required surgery within 3 years.

Conclusion

The development of new aneurysms was common in patients with a PAA; lifelong surveillance may be warranted.

Outcome after abdominal aortic aneurysm repair in Sweden 1994–2005

Background

The aim was to study the epidemiology of abdominal aortic aneurysm (AAA) repair in Sweden.

Methods

Primary AAA repairs registered in the Swedish Vascular Registry between 1994 and 2005 were studied. Mortality data were obtained from the national population registry, and age- and sex-specific populations for each calendar year from Statistics Sweden.

Results

Some 10 691 primary AAA repairs were identified. In the population aged 60 years or over the incidence of intact AAA repair increased from 27·0 per 100 000 in 1994–1999 to 28·8 per 100 000 in 2000–2005 (P = 0·006), while the incidence of surgery for ruptured AAA (rAAA) remained stable (13·8 versus 14·1 per 100 000; P = 0·595). Open repair with a bifurcated graft decreased, whereas endovascular repair (EVAR) increased to 35·0 per cent of intact AAA and 10·3 per cent of rAAA procedures in 2005. Patients who had EVAR were older than those undergoing open repair (74·1 versus 71·9 years; P &lt; 0·001). The 30-day mortality rate decreased over time for intact and ruptured aneurysm operations (P = 0·001). Age, female sex and open repair (compared with EVAR) were independently associated with a higher 30-day mortality rate in a logistic regression model.

Conclusion

The introduction of EVAR was associated with an increasing incidence of intact AAA repair, whereas the rate of rAAA was stable. Perioperative mortality rates decreased over time.

Abdominal aortic aneurysm--to screen or not to screen

With the ten WHO criteria for a screening program to be started, screening for abdominal aortic aneurysm is analyzed. Most of the criteria are fulfilled concerning the 65-year old male population, whereas concerning females we need more knowledge. Still the aneurysmal diameter is the most important factor to select patients for treatment meaning that many aneurysms are treated where rupture should never have occurred. Research projects giving more information on pathophysiological processes behind expansion and rupture should have priority.

Popliteal Artery Aneurysm with Acute Ischemia in 229 Patients. Outcome after Thrombolytic and Surgical Therapy

OBJECTIVES

The aim of this study was to assess the national management and outcome of popliteal artery aneurysm (PAA).

METHODS

In the Swedish National Registry 717 primary operations for PAA on 571 patients were registered prospectively between 1987 and 2002. 235 legs [corrected] presented with acute ischemia.

RESULTS

Median age was 70 for men and 75 for women. Immediate surgery was performed in 135 legs, including intraoperative thrombolysis in 32 cases (Immediate Surgery Group, ISG). Pre-operative thrombolysis was performed in 100 legs, followed by acute (<or=24 hours, 41 legs) or elective (59 legs) surgery (Delayed Surgery Group, DSG). DSG had smaller PAA (27 versus 37 mm, p<0.0001) and were younger (67 versus 72 years, p<0.001). Run-off was worse in DSG than in ISG (p<0.001) and improved in 87% after thrombolysis. Amputation-rate was 27% in the ISG and 7% in the DSG, P<0.0001. The ISG required fasciotomy in 30% compared to 11% of the DSG, p=0.0001.

CONCLUSION

Patients in the ISG and DSG differed in their pre-operative characteristics and were selected to the treatment modalities in a complex manner. Preoperative thrombolysis improves run-off.

Nationwide study of the outcome of popliteal artery aneurysms treated surgically

Background

The aim was to study the epidemiology and outcomes of popliteal artery aneurysm (PA) treated surgically.

Methods

Among 110 000 procedures registered prospectively in the Swedish Vascular Registry (Swedvasc), there were 717 primary operations for PA among 571 patients. Patient records were reviewed and data validated against other registries.

Results

The median age of the patients was 71 years; 5·8 per cent were women. Among 264 legs treated urgently, 235 had acute ischemia and 24 had rupture. Of patients with unilateral PA, 28·1 per cent had an aortic aneurysm, 8·4 per cent an iliac aneurysm and 9·4 per cent a femoral aneurysm. Extra-popliteal aneurysms were more common when the PAs were bilateral (P = 0·004). The rate of limb loss within 1 year of operation was 8·8 per cent; 12·0 per cent for symptomatic and 1·8 per cent for asymptomatic limbs (P &lt; 0·001). Risk factors for amputation were symptomatic disease, poor run-off, urgent treatment, age over 70 years, prosthetic graft and no preoperative thrombolysis when the ischaemia was acute. Amputation rates decreased over time (P = 0·003). Crude survival was 91·4 per cent at 1 year and 70·0 per cent at 5 years.

Conclusion

Multiple aneurysm disease was common when PAs were bilateral. Preoperative thrombolysis of acute thrombosis and the use of vein grafts for bypass improved outcome.

Fatal bleeding following delivery: a manifestation of the vascular type of Ehlers-Danlos' syndrome

INTRODUCTION

The vascular form of Ehlers-Danlos' syndrome (type IV) is a potentially lethal genetic condition because of rupture of major arteries, often in the peri-partum period.

CASE REPORT

We report a 31-year-old primipara who died from a rupture of the right subclavian artery. The patient had several symptoms and signs typical of the disease. The rupture occurred during the expulsion-phase of delivery but was recognized only on day 9.

CONCLUSION

Early recognition is crucial to avoid maternal mortality due to this genetic disorder. Once the condition is suspected, the clinical diagnosis is straightforward.

Incidence and risk of venous thromboembolism in patients with verified arterial thrombosis: a population study based on 23,796 consecutive autopsies

BACKGROUND

The relationship between atherothrombotic disease and venous thromboembolism (VTE) remains unclear.

PATIENTS AND METHODS

In a cohort of 23,796 consecutive autopsies, performed using a standardized procedure and representing 84% of all in-hospital deaths between 1970 and 1982 in an urban Swedish population, we investigated the relationship between verified arterial thrombosis and VTE, with the hypothesis that patients with thrombosis in major artery segments have increased odds of VTE.

RESULTS

We found an increased risk of VTE in patients with arterial thrombosis (Odds ratio; OR adjusted for gender and age 1.4, 95% confidence interval; CI 1.3-1.5) (P < 0.001). Patients with cervico-cranial and peripheral artery thrombosis had an excess risk even when controlling for age and major concomitant diseases. A negative association between coronary thrombosis and VTE in the univariate analysis (OR 0.7; 95% CI 0.6-0.8) (P < 0.001), was less pronounced in the multivariate analysis (OR 0.8; 95% CI 0.7-1.0) (P = 0.016).

CONCLUSIONS

A positive association between atherothrombosis and VTE was confirmed, except in patients with coronary thrombosis, where IHD as competing death cause is a possible confounder. Our findings indicate a potential for directed prevention, but may also imply similarities in etiology.

Intra-Abdominal Hypertension and Abdominal Compartment Syndrome Following Surgery for Ruptured Abdominal Aortic Aneurysm

OBJECTIVES

To investigate the importance of intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS), based on the December 2004 consensus definition, on outcome after surgery for ruptured abdominal aortic aneurysm (rAAA).

METHODS

Twenty-seven patients underwent open surgery for rAAA after the introduction of intra-abdominal pressure (IAP) measurements among patients at risk of IAH. Case-records were reviewed retrospectively. Seventeen patients underwent IAP-monitoring.

RESULTS

Of eight patients with IAP <21 mmHg none developed colonic ischaemia or ACS. Of four patients with IAP 21-25 mmHg (IAH grade III), two underwent colonic resection. One patient treated with open abdomen died from cardiac arrhythmia. Five patients had IAP >25 mmHg (IAH grade IV). All developed ACS. Two were not decompressed and both developed pulmonary complications, one died. Two underwent colonic resection and one was treated with open abdomen, all three survived. Of 10 patients not monitored for IAP, one died of cardiac complications, but no patient developed signs of colonic ischaemia or ACS. Mortality at 30 days and 1 year was 3/27 (11%).

CONCLUSION

IAH and ACS were common among patients undergoing surgery for rAAA. The ACS consensus definition seems appropriate in this clinical context. Monitoring IAP, and timely decompression of patients with IAH might improve outcome after surgery for rAAA.

Fatal nonocclusive mesenteric ischaemia: population-based incidence and risk factors

OBJECTIVES

To estimate the incidence and extension of visceral organ infarction, and to evaluate potential causes, in patients with autopsy-verified nonocclusive mesenteric ischaemia (NOMI) and transmural intestinal infarction.

SETTING

In Malmö, Sweden, the autopsy rate between 1970 and 1982 was 87%, creating possibilities for a population-based study.

DESIGN

Amongst 23 446 clinical autopsies, 997 cases were coded for intestinal ischaemia in a database. In addition, 7569 forensic autopsy protocols were analysed. In a nested case-control study within the clinical autopsy cohort, four NOMI-free controls, matched for gender, age at death and year of death, were identified for each fatal NOMI case to evaluate risk factors.

RESULTS

The overall incidence of autopsy-verified fatal NOMI was 2.0/100,000 person-years, increasing with age up to 40/100,000 person-years in octogenarians. Patients with stenosis of the superior mesenteric artery (SMA; n = 25) were older (P = 0.002) than those without (n = 37), and had more often a concomitant stenosis of the coeliac trunk (P < 0.001). Synchronous infarction in the liver, spleen or kidney occurred in one-fifth of all patients. Fatal cardiac failure [OR 2.9 (1.7-5.2)], history of atrial fibrillation [OR 2.2 (1.2-4.0)] and recent surgery [OR 3.4 (1.6-6.9)] were risk factors for fatal NOMI.

CONCLUSIONS

Fatal heart failure was the leading cause of intestinal hypoperfusion, although stenosis of the SMA and coeliac trunk, atrial fibrillation and recent surgery contributed significantly. Collaboration across specialties seems to be of utmost importance to improve the prognosis.

Long-term Results of Above Knee Femoro-popliteal Bypass Depend on Indication for Surgery and Graft-material**

OBJECTIVE To determine the long-term results of above-knee femoro-popliteal bypass with autologous saphenous vein (SV) or expanded polytetrafluoroethylene (ePTFE) in routine surgical practice.

METHODS

Data from the Swedish vascular registry, Swedvasc, was reviewed retrospectively. Patients with bypass surgery in 1996 and 1997 were assessed 5-7 years later. Data were gathered from the case-records and from clinical follow-up. The composite endpoint of graft failure included death within 30 days, occlusion, major amputation, extension of the graft to below-knee position and removal of an infected graft. Kaplan-Meier curves and Cox' proportional hazard ratios were calculated.

RESULTS

Four hundred and ninety-nine patients undergoing bypass for critical limb ischemia (CLI) (56%) or claudication (44%), SV (28%) or ePTFE (72%), were included. There were no significant differences in patient characteristics between patients with SV or ePTFE. CLI and ePTFE were risk factors for graft failure. For patients with both claudication and CLI SV grafts yielded better long-term results than ePTFE grafts ( p <0.03) and ( p <0.003), respectively. Symptom aggravation after graft occlusion was almost exclusively restricted to ePTFE grafts.

CONCLUSIONS

Femoro-popliteal bypass above-knee with SV gives good long-term results, especially for claudication. ePTFE grafts cannot be recommended in claudicants, since occlusion occurs often and frequently leads to CLI.

D-dimer testing in patients with suspected acute thromboembolic occlusion of the superior mesenteric artery

Background

There is no accurate non-invasive method available for the diagnosis of acute thromboembolic occlusion of the superior mesenteric artery (SMA). The aim of this study was to assess the diagnostic properties of the fibrinolytic marker D-dimer.

Methods

From September 2000 to April 2003 consecutive patients aged over 50 years admitted to hospital with acute abdominal pain were studied. Patients with possible acute SMA occlusion at presentation had blood samples taken within 24 h of the onset of the pain for analysis of D-dimer, plasma fibrinogen, activated partial thromboplastin time, prothrombin time and antithrombin. The value of D-dimer testing to diagnose SMA occlusion was assessed by means of likelihood ratios.

Results

Nine of 101 patients included had acute SMA occlusion. The median D-dimer concentration was 1·6 (range 0·4–5·6) mg/l, which was higher than that in 25 patients with inflammatory disease (P = 0·007) or in 14 patients with intestinal obstruction (P = 0·005). The combination of a D-dimer level greater than 1·5 mg/l, atrial fibrillation and female sex resulted in a likelihood ratio for acute SMA occlusion of 17·5, whereas no patient with a D-dimer concentration of 0·3 mg/l or less had acute SMA occlusion.

Conclusion

D-dimer testing may be useful for the exclusion of patients with suspected acute SMA occlusion.

Incidence of acute thrombo-embolic occlusion of the superior mesenteric artery--a population-based study

OBJECTIVE

To determine the incidence of acute thrombo-embolic occlusion of the superior mesenteric artery (AOSMA) in a population-based study.

MATERIAL

All clinical (n=23,446) and forensic (n=7569) autopsies performed in the city of Malmö between 1970 and 1982 (population 264,000-230,000 inhabitants). The autopsy rate was 87%.

METHODS

Calculation of the incidence of AOSMA with intestinal gangrene in those autopsies coded for bowel ischaemia (997/23,446 clinical and 9/7569 forensic autopsies). The operative procedures performed in 1970, 1976 and 1982 were also analysed.

RESULTS

Two forensic and 211 clinical autopsies demonstrated AOSMA with intestinal gangrene. Previous suspicion of intestinal ischaemia was noted in only 33%. Sixteen patients were operated. The cause-specific mortality was 6.0/1000 deaths. The incidence was 8.6/100,000 person years, increasing exponentially with age (p<0.001). Mortality was 93%.

CONCLUSIONS

The incidence and mortality of AOSMA is higher than previously reported from clinical series. There is seldom any suspicion of the diagnosis prior to death.

Acute thrombo-embolic occlusion of the superior mesenteric artery: a prospective study in a well defined population

OBJECTIVES

to characterize the clinical presentation of patients with acute thrombo-embolic occlusion of the superior mesenteric artery (SMA).

DESIGN

prospective study.

MATERIALS

twenty-four consecutive patients admitted to Blekinge County Hospital, Karlskrona, Sweden, with acute thrombo-embolic occlusion of the SMA, over a three-year period from April 1999 through March 2002.

METHODS

clinical data were registered prospectively. Incidence, diagnostic procedures and factors associated with survival were analysed.

RESULTS

the diagnosis was verified at operation in 20, and at autopsy in 4 patients. The incidence was 5.3 per 100 000 inhabitants per year. Among the 20 patients with embolic disease, atrial fibrillation was present in 95%, synchronous embolic events in 30% and warfarin treatment in 10%. D-dimer was elevated on admission in 13/13. Four patients were diagnosed at first consultation. Fifteen underwent curative revascularisation (6) or bowel resection only (9). Five were alive at one-year follow-up, of whom one had short bowel syndrome. Length of bowel ischaemia predicted institutional (p = 0.004) and one-year mortality (p = 0.005).

CONCLUSIONS

the incidence was higher than expected. Embolic occlusions predominated. Old age, atrial fibrillation, severe abdominal pain and synchronous embolus suggest the diagnosis of acute bowel ischaemia. Length of bowel ischaemia predicted outcome.

Renal hemodynamics during carbon dioxide pneumoperitoneum: an experimental study in pigs

BACKGROUND

Laparoscopic living donor nephrectomy is increasingly being performed, although the effects of carbon dioxide pneumoperitoneum (CO2 PP) on renal function and hemodynamics and the levels of vasopressin are not well studied.

METHODS

Renal blood flow, renal venous pressure, urine output, and vasopressin concentrations in renal venous blood were measured in pigs subjected to 12 mmHg of CO2 PP for 150 min.

RESULTS

Renal blood flow was decreased at induction of PP and increased during the first 30 min after exsufflation. Renal venous pressure was increased during PP. There was indirect evidence of a decrease in urine output during PP. No changes in renal venous vasopressin concentrations were seen.

CONCLUSION

A CO2 PP of 12 mmHg causes changes in renal hemodynamics and urine output. No changes in vasopressin levels were seen in this pig model, suggesting that other explanations for the observed changes must be sought.

Measuring the abdominal aorta with ultrasonography and computed tomography - difference and variability

OBJECTIVES

The aim of this study was to estimate the agreement between ultrasonography (US) and computed tomography (CT) in the measurement of aortic diameter in subjects with and without abdominal aortic aneurysms (AAA).

MATERIAL AND METHODS

Sixty-one subjects were investigated, 33 with a diameter >30mm and 28 with a diameter <30mm. Difference and variabily anteroposterior (AP) and transverse (TR) diameters were analysed.

RESULTS

In non-aneurysmal aortas US gave larger AP: 2.8mm (95% CI 1.7-4.0) and TR: 3.8mm (2.3-5.3) diameter. In AAAs the mean diameter did not differ significantly. In non-aneurysmal aortas we expect 95% of differences to be <5.7mm in AP and <7.6mm in TR measurements. In aneurysmal aortas we expect 95% of differences to be <8.0mm in AP and <10.6mm in TR measurements.

CONCLUSION

The difference and variability between US and CT varies depends on the diameter of the aorta and how it is measured. These differences have importance for clinical practice and for research.

Revascularization of the superior mesenteric artery after acute thromboembolic occlusion

BACKGROUND

The outcome and prognostic factors after revascularization of acute thromboembolic occlusion of the superior mesenteric artery (SMA) are poorly documented.

METHODS

Sixty patients with acute thromboembolic occlusion of the SMA had revascularization procedures at 21 hospitals from 1987 to 1998. They were registered prospectively in the Swedish Vascular Registry. Patient files were analysed retrospectively.

RESULTS

The median age of the patients was 76 years; 73 per cent suffered from cardiac disease and 23 per cent had previous vascular surgery. Onset of symptoms was classified as sudden (30 per cent), acute (33 per cent) or insidious (37 per cent). The occlusions were thought to be either embolic (67 per cent) or thrombotic (33 per cent). The diagnosis was suspected on first examination in 32 per cent of patients, a group whose median time to operation was shorter (P = 0.01). Fifty-eight patients had an exploratory laparotomy and subsequent revascularization, and two were treated with thrombolysis alone. Second-look laparotomy was performed in 41, and third look in eight patients; 19 required an additional bowel resection. The overall mortality rates were 43, 52, 60 and 67 per cent at 30 days, discharge, 1 and 5 years, respectively. No patient was dependent on intravenous nutrition after 1 year. Previous vascular surgery resulted in a higher institutional mortality rate (79 per cent; P = 0.02). Patients who had a sudden onset of symptoms outside hospital had a better outcome (mortality rate 27 per cent; P = 0.02).

CONCLUSION

Many non-diagnostic radiological examinations were performed and a routine second-look is warranted. The results suggest that attempts at revascularization procedures for acute mesenteric ischaemia may improve the outcome.

Influence of diagnostic criteria on the prevalence of abdominal aortic aneurysm

PURPOSE

We studied the prevalence of abdominal aortic aneurysm (AAA) in a population with high incidences of cardiovascular diseases and analyzed how the prevalence varies according to methodology and criteria.

METHODS

All men and women aged 65 to 75 years who lived in the Norsjö municipality in northern Sweden were invited to undergo an ultrasound scanning (US) examination. Those with an aortic diameter of 28 mm or more or with poor visibility on US were examined with computed tomography scanning (CT). Various recommended AAA definitions, two diagnostic methods (US and CT), and two diameters (maximum and anteroposterior) were analyzed.

RESULTS

Of 555 people invited to participate in the study, 504 accepted (248 men and 256 women; 91%). Eight subjects had undergone surgery for an AAA. Ninety-two subjects underwent CT. The mean maximum infrarenal aortic diameter was 24.6 mm (by means of US). Depending on diagnostic criteria, the AAA prevalence was 3.6% to 16.9% in men and 0.8% to 9.4% in women. Depending on which previous study was used as a comparison and the definition of AAA and diagnostic technique used, the prevalence in this study was 1.3 to 4.0 times higher for men and 2.0 to 5.8 times higher for women.

CONCLUSION

In a region in which residents have a high risk for cardiovascular disease, we found the highest prevalence of AAA ever reported within a population. The prevalence highly depends on methodology and diagnostic criteria, with a 10-fold variation. Detailed defined criteria are necessary to permit comparisons between studies: the number of individuals who have undergone surgery for AAA and whether they are included, the prevalence in 5- and 10-year age intervals, attendance rate, visibility, which diameter(s) is measured, and the prevalences with as many as possible of the four described definitions of AAA. The etiology of the high prevalence of AAA in this population needs to be investigated further.

Preliminary study of D-dimer as a possible marker of acute bowel ischaemia

BACKGROUND

Occlusion of the superior mesenteric artery (SMA) demands prompt recognition and diagnosis. No accurate diagnostic method is available. The aim of this study was to determine whether the fibrinolytic marker D-dimer is a useful early marker of acute bowel ischaemia.

METHODS

Fourteen patients suspected of having acute bowel ischaemia were analysed for an increase in plasma D-dimer level.

RESULTS

Six patients had embolic or thrombotic occlusion of the SMA and all had significantly higher D-dimer levels than those without thromboembolic occlusion (P < 0.05). Four patients with strangulation of the small bowel due to adhesions and one with a ruptured aortic aneurysm also had raised D-dimer values.

CONCLUSION

In patients with suspected thromboembolic occlusive disease of the SMA, a raised level of D-dimer indicated the presence of acute bowel ischaemia, whatever the cause. A more extensive prospective study is needed to evaluate a potential survival benefit using the test as a marker of the need for urgent laparotomy.

pHi monitoring of the sigmoid colon after aortoiliac surgery. A five-year prospective study

OBJECTIVES

to determine whether sigmoid-pHi diagnose colon ischaemia after aortoiliac surgery?

DESIGN

single-centre, non-randomised, prospective study.

PATIENTS AND METHODS

of 83 patients operated on between 1994 and 1998, 41 with risk factors for the development of colon ischaemia were monitored peri- and/or postoperatively with sigmoid-pHi. Peri-operative mortality was 26% (8/31) after operation for a ruptured abdominal aortic aneurysm (AAA), nil after operation for non-ruptured AAA. Thirty-five postoperative colonoscopies were performed. All non-survivors were examined post-mortem.

RESULTS

of six patients developing colon ischaemia after emergency operations (five for ruptured AAA) all had pHi-values <7.1 for 16-80 h. In two patients with transmural gangrene, and who had pHi-values below 6.6, pHi-monitoring permitted early diagnosis, colectomy and recovery. Three patients with mucosal gangrene were treated conservatively and recovered. Nine patients without ischaemic lesions had pHi-values <7.1, during 1-5 h, without adverse outcome. Bilateral ligation of the internal iliac arteries increased the risk of colon ischaemia (p<0.0001).

CONCLUSIONS

pHi-monitoring was diagnostic for colon ischaemia. Mucosal and transmural gangrene were distinguished. The importance of the internal iliac circulation was demonstrated. The low mortality rate, and the fact that no patient died from bowel ischaemia, suggests that sigmoid pHi-monitoring may improve survival after ruptured AAA.