Outcome and complications after intra-arterial thrombolysis for lower limb ischaemia with or without continuous heparin infusion

Background

Thrombolysis is a common treatment for acute leg ischaemia. The purpose of this study was to evaluate different thrombolytic treatment strategies, and risk factors for complications.

Methods

This was a retrospective analysis of prospective databases from two vascular centres. One centre used a higher dose of heparin and recombinant tissue plasminogen activator (rtPA).

Results

Some 749 procedures in 644 patients of median age 73 years were studied; 353 (47·1 per cent) of the procedures were done in women. The aetiology of ischaemia was graft occlusion in 38·8 per cent, acute arterial thrombosis in 32·2 per cent, embolus in 22·3 per cent and popliteal aneurysm in 6·7 per cent. Concomitant heparin infusion was used in 63·2 per cent. The mean dose of rtPA administered was 21·0 mg, with a mean duration of 25·2 h. Technical success was achieved in 80·2 per cent. Major amputation and death within 30 days occurred in 13·1 and 4·4 per cent respectively. Bleeding complications occurred in 227 treatments (30·3 per cent). Blood transfusion was needed in 104 (13·9 per cent). Three patients (0·4 per cent of procedures) had intracranial bleeding; all were fatal. Amputation-free survival was 83·6 per cent at 30 days at both centres. In multivariable analysis, preoperative severe ischaemia with motor deficit was the only independent risk factor for major bleeding (odds ratio (OR) 2·98; P <0·001). Independent risk factors for fasciotomy were severe ischaemia (OR 2·94) and centre (OR 6·50). Embolic occlusion was protective for major amputation at less than 30 days (OR 0·30; P = 0·003). Independent risk factors for death within 30 days were cerebrovascular disease (OR 3·82) and renal insufficiency (OR 3·86).

Conclusion

Both treatment strategies were successful in achieving revascularization with acceptable complication rates. Continuous heparin infusion during intra-arterial thrombolysis appeared to offer no advantage.

Sex differences in the association between smoking and abdominal aortic aneurysm

Background

It is unclear whether recommendations about ultrasound screening programmes for abdominal aortic aneurysm (AAA) among men should be extended to include women who smoke. The aim was to examine sex-specific dose–response associations between AAA risk and smoking status, pack-years smoked and time since smoking cessation.

Methods

Women in the Swedish Mammography Cohort and men in the Cohort of Swedish Men were followed up from 1998 to 2011. AAA was identified through linkage of the cohorts to the Swedish Inpatient Register and the Swedish National Register for Vascular Surgery (Swedvasc), and not through general ultrasound screening. Associations were estimated with Cox proportional hazards models.

Results

The cohorts included 35 550 women and 42 596 men, aged 46–84 years. During follow-up, AAA was identified in 199 women and 958 men. The incidence of AAA per 100 000 person-years was 76 among men who never smoked and 136 among women who currently smoke. Regarding AAA risk, women were more sensitive to current smoking (Pinteraction= 0·002). Compared with never smokers, the hazard ratio (HR) for AAA in current smokers with more than 20 pack-years was 10·97 (95 per cent confidence interval 7·41 to 16·26) among women and 6·55 (5·36 to 7·99) among men. Following smoking cessation, women had a more rapid decline in excess risk (Pinteraction &lt; 0·001). The risk was halved after 11 years (HR 0·51, 0·32 to 0·81) among women and after 23 years (HR 0·50, 0·42 to 0·60) among men.

Conclusion

There were sex differences in the associations between smoking status and AAA risk. These data support further investigation of targeted AAA screening among women who smoke.

Comparison of three ultrasound methods of measuring the diameter of the abdominal aorta

BACKGROUND

Three ultrasound methods of measuring the diameter of the abdominal aorta exist: the outer-to-outer (OTO) method, where callipers are placed on the outer layer of the aortic wall; the inner-to-inner (ITI) method, where callipers are placed on the inner layer of the aortic wall; and the leading edge-to-leading edge (LELE) method, where callipers are placed on the outer layer of the anterior wall and the inner layer of the posterior wall. The aim was to determine the variability of the three methods, differences between them, and the consequences on prevalence estimates.

METHODS

Some 127 consecutive patients with a small abdominal aortic aneurysm (AAA) were included. The maximal anteroposterior diameter was measured using the OTO, ITI and LELE methods by two vascular sonographers who were blinded to each other's measurements. The variability was described as the standard deviation.

RESULTS

The variability was 2.7 (95 per cent limits of agreements ± 5.4) mm for the OTO, 2.3 (± 4.6) mm for the ITI and 2.0 (± 4.0) mm for the LELE method. The corresponding coefficients of variability were 6.4, 6.1 and 5.0 per cent. The difference was 4.1 mm between ITI and OTO (P < 0.001), 2.0 mm between ITI and LELE (P < 0.001), and 2.1 mm between LELE and OTO (P < 0.001).

CONCLUSION

LELE measurement was the most reproducible method of measuring the abdominal aorta. All methods showed a high degree of variability.

Early sac shrinkage predicts a low risk of late complications after endovascular aortic aneurysm repair

BACKGROUND

Aneurysm shrinkage has been proposed as a marker of successful endovascular aneurysm repair (EVAR). Patients with early postoperative shrinkage may experience fewer subsequent complications, and consequently require less intensive surveillance.

METHODS

Patients undergoing EVAR from 2000 to 2011 at three vascular centres (in 2 countries), who had two imaging examinations (postoperative and after 6-18 months), were included. Maximum diameter, complications and secondary interventions during follow-up were registered. Patients were categorized according to early sac dynamics. The primary endpoint was freedom from late complications. Secondary endpoints were freedom from secondary intervention, postimplant rupture and direct (type I/III) endoleaks.

RESULTS

Some 597 EVARs (71.1 per cent of all EVARs) were included. No shrinkage was observed in 284 patients (47.6 per cent), moderate shrinkage (5-9 mm) in 142 (23.8 per cent) and major shrinkage (at least 10 mm) in 171 patients (28.6 per cent). Four years after the index imaging, the rate of freedom from complications was 84.3 (95 per cent confidence interval 78.7 to 89.8), 88.1 (80.6 to 95.5) and 94.4 (90.1 to 98.7) per cent respectively. No shrinkage was an independent risk factor for late complications compared with major shrinkage (hazard ratio (HR) 3.11; P < 0.001). Moderate compared with major shrinkage (HR 2.10; P = 0.022), early postoperative complications (HR 3.34; P < 0.001) and increasing abdominal aortic aneurysm baseline diameter (HR 1.02; P = 0.001) were also risk factors for late complications. Freedom from secondary interventions and direct endoleaks was greater for patients with major sac shrinkage.

CONCLUSION

Early change in aneurysm sac diameter is a strong predictor of late complications after EVAR. Patients with major sac shrinkage have a very low risk of complications for up to 5 years. This parameter may be used to tailor postoperative surveillance.

One-year follow-up after open abdomen therapy with vacuum-assisted wound closure and mesh-mediated fascial traction

BACKGROUND

Open abdomen (OA) therapy frequently results in a giant planned ventral hernia. Vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) enables delayed primary fascial closure in most patients, even after prolonged OA treatment. Our aim was to study the incidence of hernia and abdominal wall discomfort 1 year after abdominal closure.

METHODS

A prospective multicenter cohort study of 111 patients undergoing OA/VAWCM was performed during 2006-2009. Surviving patients underwent clinical examination, computed tomography (CT), and chart review at 1 year. Incisional and parastomal hernias and abdominal wall symptoms were noted.

RESULTS

The median age for the 70 surviving patients was 68 years, 77 % of whom were male. Indications for OA were visceral pathology (n = 40), vascular pathology (n = 22), or trauma (n = 8). Median length of OA therapy was 14 days. Among 64 survivors who had delayed primary fascial closure, 23 (36 %) had a clinically detectable hernia and another 19 (30 %) had hernias that were detected on CT (n = 18) or at laparotomy (n = 1). Symptomatic hernias were found in 14 (22 %), 7 of them underwent repair. The median hernia widths in symptomatic and asymptomatic patients were 7.3 and 4.8 cm, respectively (p = 0.031) with median areas of 81.0 and 42.9 cm(2), respectively (p = 0.025). Of 31 patients with a stoma, 18 (58 %) had a parastomal hernia. Parastomal hernia (odds ratio 8.9; 95 % confidence interval 1.2-68.8) was the only independent factor associated with an incisional hernia.

CONCLUSIONS

Incisional hernia incidence 1 year after OA therapy with VAWCM was high. Most hernias were small and asymptomatic, unlike the giant planned ventral hernias of the past.

Iatrogenic vascular injuries with lethal outcome

BACKGROUND

The aim was to study the nature of iatrogenic vascular injuries (IVIs) associated with postoperative death within 30 days.

METHODS

Patients who had undergone vascular surgery for IVIs and were reported prospectively to the Swedish national vascular registry during 1987-2008 were identified. They were cross-checked with the national population registry. Those who died within 30 days of surgery were studied regarding case records and death certificates.

RESULTS

A total of 56 patients with postoperative death within 30 days after IVI were identified. Among them, 52 case records were retrieved (93 %). In 24 cases the IVIs were caused by puncture during endovascular procedures (13 hemorrhage, 11 occlusive thrombosis), 11 by penetrating trauma during open surgery, 6 by occlusion after external compression, 6 by percutaneous accidental arterial puncture. Main symptoms were peripheral ischemia (19/52, 37 %), external bleeding (14, 27 %), and hypovolemic shock without external bleeding (10, 19 %). Main specialties involved were interventional radiology (n = 18), general surgery (n = 9), and interventional cardiology (n = 8). Overall, 22 (42 %) were avoidable, and only 13 (25 %) underwent autopsy. Within 2 weeks, 36 patients (69 %) were dead. Also, there was a higher proportion with uncertain correlation between IVI and death.

CONCLUSIONS

Interventional radiology, general surgery, and cardiology are the main specialities involved in IVIs with lethal outcome. Not all fatalities after IVI are attributable to the injury itself, but almost half of the injuries were considered avoidable.

Management of abdominal compartment syndrome and the open abdomen

OBJECTIVES

The management of the abdominal compartment syndrome (ACS) and the open abdomen (OA) are important to improve survival after major vascular surgery, in particular ruptured abdominal aortic aneurysm (RAAA). The aim is to summarize contemporary knowledge in this field.

METHODS

The consensus definitions of the World Society of the Abdominal Compartment Syndrome (WSACS) that were published in 2006 and the clinical practice guidelines published in 2007 were updated in 2013. Structured clinical questions were formulated (modified Delphi method), and the evidence base to answer those questions was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines.

RESULTS

Most of the previous definitions were kept untouched, or were slightly modified. Four new definitions were added, including a definition of OA and of lateralization of the abdominal wall, an important clinical problem to approach during prolonged OA treatment. A classification system of the OA was added. Seven recommendations were formulated, in summary: Trans-bladder intra-abdominal pressure (IAP) should be monitored in patients at risk. Protocolized monitoring and management are recommended, and decompression laparotomy if ACS. When OA, protocolized efforts to obtain an early abdominal fascial closure, and strategies utilizing negative pressure wound therapy should be used, versus not. In most cases the evidence was graded as weak or very weak. In six of the structured clinical questions, no recommendation could be made.

CONCLUSION

This review summarizes changes in definitions and management guidelines of relevance to vascular surgery, and data on the incidence of ACS after open and endovascular aortic surgery.

Popliteal artery injury during knee replacement

Popliteal artery injury (PAI) is a feared complication during knee replacement. Our aim was to investigate those injuries that occurred in association with knee replacement in terms of the type of injury, treatment and outcomes.

From our national vascular registry (Swedvasc) and the Swedish Patient Insurance databases a total of 32 cases were identified. Prospective data from the registries was supplemented with case-records, including long-term follow-up.

We estimated the incidence during 1998 to 2010 to be 0.017%. In our series of 32 patients with PAI occurring between 1987 and 2011, 25 (78%) were due to penetrating trauma and seven were caused by blunt trauma. The patients presented in three ways: bleeding (14), ischaemia (7) and false aneurysm formation (11), and five occurred during revision surgery. A total of 12 injuries were detected intra-operatively, eight within 24 hours (3 to 24) and 12 at more than 24 hours post-operatively (2 to 90 days). Treatment comprised open surgery in 28 patients. Patency of the vascular repair at 30 days was 97% (31 of 32, one amputation). At the time of follow-up (median 546 days, mean 677 days (24 to 1251)), 25 patients had residual symptoms. Of seven patients with a complete recovery, six had had an early diagnosis of the PAI during the procedure, and were treated by a vascular surgeon in the same hospital.

PAI is a rare adverse event during knee replacement surgery. The outcome following such events is often adversely affected by diagnostic and therapeutic delay. Bleeding and false aneurysm were the most common clinical presentations.

Cite this article: Bone Joint J 2013;95-B:1645–9.

Modern treatment of acute mesenteric ischaemia

BACKGROUND

Diagnosis of acute mesenteric ischaemia in the early stages is now possible with modern computed tomography (CT), using intravenous contrast enhancement and imaging in the arterial and/or portal venous phase. The availability of CT around the clock means that more patients with acute mesenteric ischaemia may be treated with urgent intestinal revascularization.

METHODS

This was a review of modern treatment strategies for acute mesenteric ischaemia.

RESULTS

Endovascular therapy has become an important alternative, especially in patients with acute thrombotic superior mesenteric artery (SMA) occlusion, where the occlusive lesion can be recanalized either antegradely from the femoral or brachial artery, or retrogradely from an exposed SMA after laparotomy, and stented. Aspiration embolectomy, thrombolysis and open surgical embolectomy, followed by on-table angiography, are the treatment options for embolic SMA occlusion. Endovascular therapy may be an option in the few patients with mesenteric venous thrombosis who do not respond to anticoagulation therapy. Laparotomy is needed to evaluate the extent and severity of visceral organ ischaemia, which is treated according to the principles of damage control surgery.

CONCLUSION

Modern treatment of acute mesenteric ischaemia involves a specialized approach that considers surgical and, increasingly, endovascular options for best outcomes.

Abdominal aortic aneurysm and new WHO criteria for screening

Does screening of abdominal aortic aneurysm (AAA) fulfil the recently revised the World Health Organization WHO criteria for screening? Contemporary data from the literature are used to analyze whether the ten recent WHO criteria can be used to motivate AAA screening. Although the prevalence of AAA seems to decrease, at least screening of 65-year old males saves lives and is cost-effective. Ultrasonographic screening for AAA in risk populations fulfils the new WHO criteria for screening.

Changes in the management of infrarenal abdominal aortic aneurysm disease in Sweden

Background

Treatment of abdominal aortic aneurysm (AAA) has changed over time, with endovascular repair (EVAR) being the main technical revolution. This study assessed the effect of this change on outcome on a national basis over a 17-year interval.

Methods

Primary infrarenal AAA repairs in Swedish residents aged 50 years and older, in the Swedish Vascular Registry (Swedvasc) 1994–2010, were analysed. The rate per 100 000 population, patient characteristics, operative technique and outcome were assessed for the intervals 1994–1999, 2000–2005 and 2006–2010.

Results

Some 11 336 intact aneurysm repairs were performed. The overall rate per 100 000 increased (18·4 in 1994–1999, 19·4 in 2000–2005 and 24·0 in 2006–2010; P &lt; 0·001), most noticeably among older people (18 per cent increase among those aged 50–64 years, P = 0·004; 27 per cent in 65–79-year-olds, P &lt; 0·001; 128 per cent in those aged at least 80 years, P &lt; 0·001). The use of EVAR increased rapidly after 2005 (rate: 0·6 in 1994–1999, 4·4 in 2000–2005 and 11·8 in 2006–2010; P &lt; 0·001). The 30-day mortality rate decreased after open repair (4·7, 3·4 and 2·7 per cent respectively; P &lt; 0·001), but was stable after EVAR (2·6, 2·2 and 1·6 per cent; P = 0·227). Some 4972 ruptured aneurysm (rAAA) repairs were performed. The rate decreased after 2005 (9·3 in 1993–1999, 9·3 in 2000–2005 and 8·4 in 2006–2010; P = 0·006). The use of EVAR for rAAA increased over time (rate: 0, 0·5 and 1·6 respectively; P &lt; 0·001), whereas open repair decreased (9·3, 8·8 and 6·8; P &lt; 0·001). Thirty-day mortality decreased over time (38·3, 32·8 and 28·4 per cent; P &lt; 0·001).

Conclusion

The introduction of EVAR has been associated with an increased number of intact AAA repairs, which has accelerated recently, whereas the rate of rAAA repair has started to decline. Simultaneously, outcomes have improved.

The Role of Hybrid Procedures in the Management of Peripheral Vascular Disease

This paper provides a summary of up-to-date information and experience with the combined treatment of patients suffering from peripheral arterial disease (PAD) with endovascular and open surgery, performed simultaneously and in a single operating room. Hybrid intervention is reported to have good results in well-indicated groups of patients with acute and chronic limb ischemia, even with older, high-risk patients. The indications for the use of this technique remain unclear with inconsistent opinions among vascular surgeons. The indications for treatment were divided into three main groups: 1) Patients with chronic limb ischemia, 2) acute limb ischemia, and 3) occlusion of a previous vascular reconstruction. The operating techniques for the most commonly used combinations are described.

In conclusion, hybrid operating techniques are often useful when treating complex problems and multilevel disease in patients with chronic or acute lower limb ischemia. Modern vascular surgeons need to master both open and endovascular techniques, and to combine them in a creative fashion to the benefit of our patients.

Obesity and abdominal aortic aneurysm

Background

The relationship between obesity and abdominal aortic aneurysm (AAA) is unclear. An observational cohort study was undertaken to examine the associations between waist circumference as a measure of abdominal adiposity, and between body mass index (BMI) as a measure of total adiposity, and risk of AAA.

Methods

Data were used from the population-based Swedish Mammography Cohort and the Cohort of Swedish Men, involving 63 655 men and women, aged 46–84 years. Between 1998 and 2009, 597 patients with incident AAA defined by relevant clinical events were identified by linkage to the Swedish Inpatient Register and the Swedish Vascular Registry. Cox proportional hazards models were used to estimate relative risks (RRs) with 95 per cent confidence intervals.

Results

In multivariable analysis, individuals with an increased waist circumference had a 30 per cent higher risk of AAA (RR 1·30, 95 per cent confidence interval 1·05 to 1·60) compared with those with a normal waist circumference. The risk of AAA increased by 15 per cent (RR 1·15, 1·05 to 1·26) per 5-cm increment of waist circumference up to the level 100 cm for men and 88 cm for women. There was no association between BMI and risk of AAA.

Conclusion

Abdominal, but not total, adiposity was associated with an increased risk of incident AAA. A threshold was observed at a waist circumference of 100 cm for men and 88 cm for women.

Current prevalence of abdominal aortic aneurysm in 70-year-old women

BACKGROUND

Screening elderly men for abdominal aortic aneurysm (AAA) to reduce mortality from rupture is evidence-based. For women epidemiological data on AAA are scarce, and the evidence for screening is insufficient. The aim of this population-based study was to determine the current prevalence of AAA and risk factors among 70-year-old women.

METHODS

All 70-year-old women identified through the National Population Registry in the two neighbouring counties of Uppsala and Dalarna were invited to a free ultrasound examination of the abdominal aorta. An AAA was defined as a maximum infrarenal aortic diameter of at least 30 mm.

RESULTS

Of 6925 women invited, 5140 (74·2 per cent) accepted the invitation to be screened. Among these, 19 AAAs were detected (0·4 (95 per cent confidence interval (c.i.) 0·2 to 0·5) per cent). In the invited cohort 12 women (0·2 (0·1 to 0·3) per cent) had undergone previous AAA repair (11) or had a known AAA under surveillance (1). Thus, the total prevalence was estimated at 0·5 (0·4 to 0·7) per cent. Smoking was strongly associated with AAA; 18 (95 per cent) of 19 women with a screen-detected AAA had a history of smoking compared with 44·2 per cent of those with a normal aorta (odds ratio 20·29, 95 per cent c.i. 2·70 to 152·65). The prevalence of AAA was 0·03 (0 to 0·1) per cent among never smokers, 0·4 (0·2 to 0·8) per cent among former smokers and 2·1 (1·0 to 3·7) per cent among current smokers.

CONCLUSION

Screening 70-year-old women who do not smoke is likely to be futile, thus ruling out population screening of women for AAA.

Atomic imaging and direct phase retrieval using anomalous surface x-ray diffraction

The application of multi-wavelength anomalous diffraction to thin films, interfaces and surface structures is presented. The method directly determines the amplitudes and phases of the complex surface structure factors from surface x-ray diffraction data, measured at three different energies around the absorption edge of one of the elements present in the film. Thereby, one is able to directly Fourier transform the data, which immediately provides meaningful and unambiguous electron-density distributions. These serve as a starting point for subsequent structural refinement. The robustness of the algorithm was evaluated on simulated data as a proof of principle. The experimental limitations and their effect on the method will be discussed as well as stability tests for the algorithm, such as the positions of the anomalous scatterers and the interfacial roughness. It will be shown that the method can be applied to real structures. The algorithm was tested on real data from a thin film of SrTiO(3) grown on NdGaO(3)(110).

Quadracyclic adenine: a non-perturbing fluorescent adenine analogue

Fluorescent-base analogues (FBAs) comprise a group of increasingly important molecules for the investigation of nucleic acid structure and dynamics as well as of interactions between nucleic acids and other molecules. Here, we report on the synthesis, detailed spectroscopic characterisation and base-pairing properties of a new environment-sensitive fluorescent adenine analogue, quadracyclic adenine (qA). After developing an efficient route of synthesis for the phosphoramidite of qA it was incorporated into DNA in high yield by using standard solid-phase synthesis procedures. In DNA qA serves as an adenine analogue that preserves the B-form and, in contrast to most currently available FBAs, maintains or even increases the stability of the duplex. We demonstrate that, unlike fluorescent adenine analogues, such as the most commonly used one, 2-aminopurine, and the recently developed triazole adenine, qA shows highly specific base-pairing with thymine. Moreover, qA has an absorption band outside the absorption of the natural nucleobases (>300 nm) and can thus be selectively excited. Upon excitation the qA monomer displays a fluorescence quantum yield of 6.8 % with an emission maximum at 456 nm. More importantly, upon incorporation into DNA the fluorescence of qA is significantly less quenched than most FBAs. This results in quantum yields that in some sequences reach values that are up to fourfold higher than maximum values reported for 2-aminopurine. To facilitate future utilisation of qA in biochemical and biophysical studies we investigated its fluorescence properties in greater detail and resolved its absorption band outside the DNA absorption region into distinct transition dipole moments. In conclusion, the unique combination of properties of qA make it a promising alternative to current fluorescent adenine analogues for future detailed studies of nucleic acid-containing systems.

Evolution of the interfacial structure of LaAlO3 on SrTiO3

The evolution of the atomic structure of LaAlO_{3} grown on SrTiO_{3} was investigated using surface x-ray diffraction in conjunction with model-independent, phase-retrieval algorithms between two and five monolayers film thickness. A depolarizing buckling is observed between cation and oxygen positions in response to the electric field of polar LaAlO_{3}, which decreases with increasing film thickness. We explain this in terms of competition between elastic strain energy, electrostatic energy, and electronic reconstructions. Based on these structures, the threshold for formation of a two-dimensional electron system at a film thickness of 4 monolayers is quantitatively explained. The findings are also qualitatively reproduced by density-functional-theory calculations.