Presenting Baseline Coagulation of Infra Renal Ruptured Abdominal Aortic Aneurysm: A Systematic Review and Pooled Analysis.

BACKGROUND: The incidence of coagulopathy in patients presenting with rAAA is not clear. The lack of high-quality evidence has led to various speculations, reliance on anecdotal experience, and suggestions about their appropriate haemostatic resuscitation. The aim of this systematic review is to establish the baseline coagulation status of infra renal ruptured abdominal aortic aneurysms (rAAA) against defined standards and definitions. METHODS: An electronic search of literature in Medline, CINHAL, Scopus Embase, and Cochrane library was performed in accordance with the PRISMA guidelines. Quality assessment of articles was performed using the Oxford critical appraisal skills programme (CASP) and their recommendation for practice was examined through National Institute for Health and Care Excellence (NICE). Information on platelet count, international normalisation ratio (INR), activated partial prothrombin time (aPTT), prothrombin time (PT) fibrinogen and D-dimer was extracted, and pooled analysis was performed in accordance with the definition of coagulopathy and its subtypes. Pooled prevalence of coagulopathies and 95% CI were estimated with a variance weighted random effects model. RESULTS: Seven studies, comprising 461 patients were included in this systematic review. Overall weighted prevalence of coagulopathy was 12.3% (95% CI 10.7-13.9), 11.7% for INR (95% CI 1-31.6), 10.1% for platelet count (95% CI 1-26.8), and 11.1% for aPTT (95% CI 0.78-31). Fibrinogen serum concentration level was normal in 97%, and 46.2% (n = 55) of patients had elevated D-dimer. Only 6% of the entire population demonstrated significant coagulopathy. DIC was noted in 2.4% of the population. CONCLUSION: This first systematic review of literature on baseline coagulation of rAAAs suggests that the majority of these patients do not present with coagulopathy and only a minor proportion of patients present with significant coagulopathy.

Does the establishment of a Vascular Unit reduce the prevalence of ruptured aortic aneurysms?

AIM: The aim of this study was to assess the effect of a specialised Vascular Unit upon the prevalence of ruptured aortic aneurysms in the same population catchments' area and associated mortality rates. SETTING: prospective computerised data collection from 1997 to today, retrospective from 1990-1996. SUBJECTS: 108 aneurysms were operated upon from 1990-1996, compared to 317 from 1997 to Aug 2002. MAIN OUTCOME MEASURES: statistical analysis was done using SPSS statistics with Kaplan Meier life table curves and compared by the log rank test while the Mann Whitney test was used for comparison of mortality. RESULTS: The median values for ruptured aneurysms per year were 5 for the early period, compared to 10 for the recent years, while the median values for both urgent and ruptured were 7 and 18.5 cases annually, respectively. The number of scheduled procedures increased by 500% in the second period, with median values of 7 and 36.5, respectively. In-hospital mortality according to category was 21% for scheduled, 31% for urgent and 69% for ruptured aneurysms in the early period, compared to 3.7%, 16% and 29% respectively, following the establishment of the Vascular Unit. CONCLUSION: Despite the five-fold increase in the total number of aortic aneurysm repairs (as expected), the number of ruptured aneurysms operated upon increased as well. There was just a trend for a reduction in the absolute numbers of ruptured aneurysms operated upon in the last 2 years. Mortality, on the other hand, decreased dramatically in all categories, with the overall 30-day mortality decreasing more than four-fold, from 40% to 9.3%, while the respective mortalities according to the category of intervention were 3.7% vs 21% for scheduled, 16% vs 35% for urgent and 29% vs 69% for ruptured aneurysms, with a P value of less than 0.01. However, there was no difference in the numbers of patients with ruptured aneurysm reaching the hospital (operated or not) between the two periods (median values of 11 and 10.5 annually). The presence of a Vascular Unit, although it achieves dramatically better results, is not associated with a reduction in the number of emergency proceduresaeat least in the intermediate termaedespite an expansion in the indications for surgery, increased awareness and prompt referrals (centralisation).

A scoring system to predict the outcome of long femorodistal arterial bypass grafts to single calf or pedal vessels.

OBJECTIVES: The aim of this study was to develop a scoring system to predict the outcome of long femorocrural and femoropedal bypass grafts performed for critical limb ischaemia. SETTING: Teaching hospital. METHODS: An analysis of 109 consecutive femorodistal bypass grafts performed for critical lower limb ischaemia between June 1991 to December 1994. Factors shown to affect the outcome were: inflow, number of patent calf vessels, graft material, straight flow to the foot and patent pedal vessels. These variables were weighted according to their relative significance (multivariate Cox regression) and a scoring system (ranging from 0 to 10) was developed. RESULTS: Patients with a preoperative score of 0-4 (n = 35) showed a secondary patency of 36% at 1 month, 12% at 3 months and 0% at 10 months (Cum SE = 6.90/0.0). Secondary patency rates for the 46 patients with score 5-7 were 88.7% at 3 months, 56.3% at 12, and 45.1% at 2 and 3 years (Cum SE = 9.82), while the respective values for the 28 patients with score 8-10 were 92.7%, 88.5% and 81.7% (Cum SE = 8.08). The difference was highly significant (p = 0.000) in all tests of equality. In addition, the median total hospital cost was 12,600 Pounds for the group 0-4 compared with 8100 Pounds (group 5-7) and 4400 Pounds (group 8-10) (p = 0.0085). CONCLUSIONS: This preoperative scoring system appears to correlate well with the outcome of distal revascularisation to single calf or pedal vessels. If applied to patient selection, it could significantly reduce the total hospital cost per leg saved. A prospective testing of its predictive ability is needed and is in progress.

A paper for debate: vein versus PTFE for critical limb ischaemia--an unfair comparison?

INTRODUCTION: There is a widely held view that vein grafts for infrainguinal arterial reconstruction perform much better than prosthetic conduits, the best of which seems to be PTFE. Many randomised studies have been conducted which confirm this opinion, but is the difference as large as it is thought to be? One interesting feature of published trials is that the results for obligatory PTFE (when no vein is available) were much worse than the results for randomised PTFE grafts. The only way to explain this is that these groups of patients were not similar, and there are probably other factors which contribute to the difference in results when vein and PTFE grafts are compared. MATERIALS AND METHODS: A consecutive series of 109 femoro-infrapopliteal grafts undertaken for critical limb ischaemia was analysed to see the difference between vein and PTFE with vein cuff grafts. RESULTS: Vein grafts were superior to PTFE grafts when the whole cohort was included (p = 0.0038); however, there was no significant difference when the patients were stratified for inflow and runoff status. CONCLUSIONS: The difference between vein and PTFE has probably been exaggerated in the past, due to differences in risk factors and in the extent of arterial disease between the two groups of patients. The advantage of vein becomes more significant with time.

The concept of knee salvage: why does a failed femorocrural/pedal arterial bypass not affect the amputation level?

OBJECTIVES: There is continued controversy over whether a failed distal bypass influences the level of amputation. This issue is important as the number of arterial bypass grafts undertaken for critical ischaemia is increasing, followed by an increasing number of failed grafts. SETTING: Teaching hospital. STUDY DESIGN AND MATERIALS: A prospective analysis of 109 consecutive femorocrural/pedal bypass grafts performed between June 1991 and January 1995 on patients presenting with severe critical lower limb ischaemia (CLI) to a single vascular unit. A further 43 amputations for non-reconstructible distal disease were also analysed. CHIEF OUTCOME MEASURES: Mortality, amputation, rehabilitation, survival and knee salvage rates. The Kaplan-Meier method was used for comparison of factors associated with knee preservation. RESULTS: Primary amputees had a higher in-hospital mortality (18% vs. 10%) but similar 3 year survival rates (30%) compared with secondary amputees (36.6%). Patients with successful grafts showed a trend towards better survival (61.9% at 3 years) compared to amputees (38.6% at 42 months, p = 0.061). Below- to above-knee amputation ratio was similar in the two groups (0.85 in secondary vs. 0.95 in primary amputees). Factors significantly associated with knee salvage at 3 years were shown to be: the condition of the inflow (81.9% for good vs. 43.1% for impaired, p = 0.000) the state of the profunda femoris artery (good 93%, impaired 71%, occluded 37% p = 0.0001) and the graft material (vein 81.8% vs. PTFE 59.8%, p = 0.033). The presence of tissue loss (p = 0.0523) and secondary procedures (p = 0.0879) showed a trend to become significant. Multivariate and Cox regression analysis showed that the most important factors were the inflow (p = 0.001), the state of the profunda (p = 0.001), the graft material (p = 0.034) and previous revascularisation attempts (p = 0.019). CONCLUSIONS: The factors which determine knee loss are a compromised inflow state, the presence of an inadequate profunda femoris, previous revascularisation attempts and the use of synthetic graft material. Most of these factors (with the exception of infection related to revascularisation) are present before reconstructive arterial surgery is performed and this study shows that failure of a distal graft does not affect the final amputation level.

Results and cost analysis of distal [crural/pedal] arterial revascularisation for limb salvage in diabetic and non-diabetic patients.

In order to compare the outcome and costs of femorodistal grafting in diabetic and nondiabetic patients presenting with critical limb ischaemia we analysed a consecutive series of 109 femorodistal bypasses, 38 (35%) performed on people with diabetes and 71 (65%) on non-diabetic patients. The same aggressive revascularization policy was used in both groups with the decision to operate based on the presence of a calf or foot vessel on preoperative intra-arterial digital subtraction angiography (IADSA). Data were collected prospectively and the median follow-up was 15.4 months (range 0 to 42 months). There were no significant differences in 30-day (5.3% vs 4.2%) and in-hospital mortality (13.2% vs 14.1%) between the two groups. Life table curves at 3 years in diabetic and non-diabetic patients showed 48% vs 60% survival, 76% vs 72% knee salvage, 45% vs 56% limb salvage, and 38% vs 47% secondary patency. Although there was a trend for diabetic patients to perform less well, there was no statistically significant difference in these outcome measures. In cost comparison the only significant difference was found in the total hospital cost, which was Pounds 9181 in diabetic, compared to Pounds 6350 in nondiabetic patients (p = 0.026, Mann-Whitney). However, this cost was significantly less than that of primary amputation in either group (Pounds 15500 and Pounds 12040, respectively). Femorodistal reconstruction in both diabetic and non-diabetic patients, whenever feasible, is a cheaper option than primary amputation, even though vascular surgery may be more expensive in people with diabetes.

Outcome and cost analysis after femorocrural and femoropedal grafting for critical limb ischaemia.

BACKGROUND: The past decade has seen an increase in the use of distal arterial bypass grafts for treating critical lower limb ischaemia. However, this surgical policy is associated with variable results. The aims of this study were to identify factors that affect outcome and to calculate the cost of such surgical interventions. METHODS: A prospective analysis of femorocrural and femoropedal bypass grafts and primary amputations was performed between June 1991 and January 1995. A consecutive series of 109 limbs with critical lower limb ischaemia underwent a bypass graft to a single crural or pedal vessel shown on either preoperative intra-arterial digital subtraction angiography or at surgical exploration. Complete data were available for all patients during follow-up which ranged from 0 to 42 (median 12) months. The factors assessed were age, sex, diabetes, pedal arch, graft material, outflow vessel, number of calf vessels, number of vessels crossing the ankle, inflow state, previous revascularization procedures and foot gangrene and tissue necrosis. Chief outcome measures were survival, knee and limb salvage, patency rates and hospital cost. The Kaplan-Meier method was used to construct life tables and the log rank test for comparison of factors. Cost was measured according to National Health Service criteria, and comparisons were made by the Mann-Whitney U test. RESULTS: At 36 months primary patency was 27 per cent, primary assisted patency 31 per cent and secondary patency 45 per cent; limb salvage was 54 per cent, knee salvage 73 per cent and survival 58 per cent. Significant factors in predicting outcome were graft material (P = 0.004), inflow state (P = 0.0001), number of calf vessels (P = 0.039), number of vessels crossing the ankle (P < 0.0001) and the condition of pedal vessels (P < 0.0001). Cost analysis showed that the median price for a successful bypass was 4320 pounds, that of a failed bypass leading to amputation 17,066 pounds and that of primary amputation in patients with non-reconstructable distal disease 12,730 pounds. CONCLUSION: The patency rate of femorotibial and peroneal bypass depends on the inflow state, the availability of a venous conduit, the number of calf vessels, the presence of straight flow to the foot and the presence of patent pedal vessels. These factors can help in the selection of patients for femorodistal reconstruction and may explain the wide variation in published results. The low cost of revascularization compared with amputation justifies attempted reconstruction. However, repeated attempts to reconstruct patients with severe distal disease who may benefit more from primary amputation will significantly increase the cost.

The changing indications for carotid endarterectomy in the UK.

In early series the majority of carotid endarterectomies were performed in patients with amaurosis fugax (AFx) or transient ischaemic attacks (TIAs) who were thought to have atheromatous ulcers of the carotid bifurcation or the internal carotid artery (ICA). The degree of stenosis was considered to be of secondary importance. We compared our own data with two British series undertaken in the early and late 80s/early 90s. This reflects the broadening of indications and the change of practice for carotid endarterectomy over the years, on the one hand towards including patients who are at greater risk of perioperative stroke (previous CVAs vs TIAs, crescendo TIAs and stroke in evolution), and on the other towards patients who have had no symptoms attributable to the carotid lesion (asymptomatic cases, combined carotid and cardiac procedures).

Problems related to the definition of "distal" bypass and "secondary" patency rates. A paper for debate.

The large variations observed in "distal" bypass patency rates and the abuse of life-table analysis have encouraged most Vascular Committees to develop standards for evaluating results. However, problems continue to persist. Some of these do not relate to statistical analysis but to the lack of definition of both secondary patency and "distal" when referring to arterial bypass grafts to the lower limb. We present various problems and propose some strict definitions for each type of infrainguinal reconstruction, based on the inflow and outflow levels, together with a modification of the definitions of primary assisted and secondary patency.

Endovascular repair of residual iliac artery aneurysms following surgery for ruptured abdominal aortic aneurysm.

Emergency repair of ruptured abdominal aortic aneurysm continues to have a high mortality. Such patients require expeditious operations to repair the ruptured segment rather than attempts to deal with all coexisting disease. The use of endovascular techniques obviates the need for open surgery to repair iliac aneurysms. We report two patients who, after successful repair of ruptured abdominal aortic aneurysms, had three iliac artery aneurysms treated successfully by embolisation in one case and percutaneous insertion of a self expandable stent graft in two cases. The issues that arise from such an approach are discussed with a review of the literature.

Aneurysms of the visceral and renal arteries.

Visceral aneurysms represent a rare clinical entity; however, 10-20% will rupture and this is accompanied by a significant mortality rate of 20-70%, depending on the location of the aneurysm. The incidence, pathogenesis and clinical aspects of splanchnic and renal artery aneurysms are reviewed from the available literature and the problems of diagnosis and treatment are discussed. Their incidence is increasing and controversy still exists regarding their treatment. The decision for intervention has to take into account the size and the natural history of the lesion, the risk of rupture, which is high during pregnancy, and the relative risk of surgical or radiological intervention. For most asymptomatic aneurysms, expectant treatment is acceptable. For large, symptomatic or aneurysms with a high risk of rupture, surgery is advisable. An alternative treatment is the use of endovascular techniques, ie embolisation, or graft stent insertion.

Surgery for asymptomatic carotid artery stenosis.

The recent European Carotid Surgery Trial (ECST) and North American Symptomatic Carotid Endarterectomy Trial (NASCET) have clearly defined a population who benefit from carotid artery endarterectomy (CAE). However these trials used different criteria to identify > 70% stenosis of the internal carotid artery (ICA). The role of CAE in asymptomatic ICA stenosis has been investigated by the Carotid Artery Stenosis with Asymptomatic Narrowing Operation Versus Aspirin (CASANOVA) study, the Veterans Administration Asymptomatic Carotid Study (VAACS) and the Asymptomatic Carotid Artery Stenosis (ACAS) trials, all of which have design limitations. The Asymptomatic Carotid Stenosis Trial (ACST) is still recruiting patients but until the natural history of asymptomatic ICA disease is understood, the role of surgical intervention will continue to be controversial.

Non-invasive assessment of arterial disease: a comparison of Quickscan with intra-arterial digital subtraction angiography.

The ability of Quickscan to identify haemodynamically significant lesions in the arteries of the lower limb was studied. Quickscan was prospectively compared with intra-arterial digital subtraction angiography (IADSA) of the iliac, femoral and popliteal arteries. In 155 patients, 631 arterial segments were evaluated. A Quickscan frequency ratio of 1:3 or greater had a sensitivity of 93 per cent and a specificity of 85 per cent in detecting a stenosis of more than 50 per cent diameter reduction (67 per cent area reduction) in the iliac artery, as shown on IADSA. The sensitivity and specificity in the femoral artery were 85 and 96 per cent respectively, and in the popliteal artery 82 and 98 per cent respectively. In the detection of occlusion, Quickscan had a sensitivity and specificity of 84 and 98 per cent respectively in the iliac artery, 94 and 97 per cent respectively in the femoral artery, and 94 and 85 per cent respectively in the popliteal artery. Quickscan is an inexpensive, quick and non-invasive method of screening for peripheral vascular disease in the lower limb.

Mid-aortic syndrome presenting in childhood.

Mid-aortic syndrome (MAS) is an uncommon condition characterized by segmental narrowing of the proximal abdominal aorta and ostial stenosis of its major branches. It is usually diagnosed in young adults, but may present in childhood as a challenging problem. Over the past 20 years 13 patients with MAS have presented to this institution. All had hypertension, four had associated neurofibromatosis, three persistent eosinophilia and three had Williams syndrome. In all cases arteriography showed a smooth segmental narrowing of the abdominal aorta with concomitant stenosis at the origins of the renal arteries. Six children were successfully treated with antihypertensive medication alone. Percutaneous transluminal angioplasty was attempted in two cases with poor result. Surgery was indicated in seven children with refractory hypertension and progressive renal impairment. Techniques used to revascularize the kidneys included thoracoabdominal to infrarenal aortic bypass with renal artery reimplantation, splenorenal bypass, gastroduodenal to renal bypass, aortorenal bypass and autotransplantation.