T Troeng

Incidence and Clinical Presentation of Bowel Ischaemia After Aortoiliac Surgery--2930 Operations from a Population-based Registry in Sweden*

OBJECTIVES To study the incidence and clinical presentation of intestinal ischaemia after aortoiliac/femoral surgery, and to validate a vascular registry concerning a serious complication. DESIGN AND SETTING In the Swedish Vascular Registry (SWEDVASC) the outcome and complications of all vascular procedures are registered prospectively. MATERIALS AND METHODS All 2930 patients operated in 1987-93 were analysed for notified complications. A 5% random sample of all patients and a 20% random sample of fatal cases were analysed for un-notified complications. Of 415 requested patient records 413 were analysed. RESULTS The estimated incidence of bowel ischaemia was 2.8%. Among patients operated on for a ruptured aneurysm in shock it was 7.3%. Of the 63 patients with intestinal ischaemia only 15 presented with early passage of bloody stools. In 60 patients (95%) the lesion affected the left colon within the reach of a sigmoidoscope. Bowel ischemia was unnotified only in fatal cases, the estimated un-notified complication rate was 0.7%. CONCLUSIONS The incidence in this study on unselected patients did not differ from previous reports from specialised centres. Diagnosis is difficult and justifies a high index of suspicion and early use of sigmoidoscopy. The validity of the SWEDVASC registry was confirmed by a high report-rate for this complication.

External validation of the Swedvasc registry : a first-time individual cross-matching with the unique personal identity number

OBJECTIVE To study external validity of the Swedvasc registry concerning numbers of procedures and mortality. MATERIALS AND METHODS Vascular registry data for carotid, infrainguinal bypass and aortic aneurysm (AAA) procedures were compared to the Swedish Hospital Discharge Register (SHDR) data, and the National Population Registry (for mortality) by matching every individual patient using the unique personal identity numbers (PINs). The time-period studied was 2000-2004 (5 years) for carotid and infrainguinal procedures. A separate analysis was performed for AAA-surgery in 2006. RESULTS The external validity for carotid, infrainguinal bypass and AAA repair was 93.4%, 93.0% and 93.1%, respectively. The 30-day mortality was 0.86% after carotid and 2.9% after infrainguinal bypass procedures. Mortality was 2.6% after planned and 25.9% after unplanned AAA repair. Although there was a general trend towards inferior outcomes after procedures not registered in the Swedvasc, those procedures were so few that in none of the analyses did the inclusion of non-registered procedures affect general outcomes significantly. Combining data from both registries, the incidence for carotid, infrainguinal bypass and AAA procedures was 7.8, 15.2 and 13.6 per 100,000 person-years, respectively. In the hospital-specific analysis for 2006 it was shown that the non-registered procedures for AAA were localized to one non-compliant county hospital, and small district hospitals not performing elective AAA-surgery but only rare emergency operations. CONCLUSION The external and internal validity of the Swedvasc registry allows to confidently assess volumes of, and mortality after, vascular surgery in Sweden.

Risk Factors for Intestinal Ischaemia after Aortoiliac Surgery: a Combined Cohort and Case-control Study of 2824 Operations

OBJECTIVE To identify risk factors for intestinal ischaemia after aortoiliac surgery. MATERIALS AND METHODS Among 2824 patients operated on during 1987-93 and registered prospectively in the Swedish Vascular Registry, 62 cases of postoperative intestinal ischaemia were identified. They were compared with the remaining 2762 patients through the registry and with a random sample of 127 controls through patient records. Multivariate analysis was performed. RESULTS Patients in shock operated on for ruptured aneurysms were at greatest risk of developing postoperative intestinal ischaemia. Excluding patients in shock, operation for aneurysmal disease and for occlusive disease carried the same risk. Renal disease, emergency surgery, age, type of hospital, aortobifemoral graft, operating time, cross-clamping time and ligation of one or both internal iliac arteries were independent risk factors. CONCLUSIONS Patient-related haemodynamic risk factors together with surgical skill and decision making defines the risk for this serious complication.

Volume versus outcome when treating abdominal aortic aneurysm electively : is there evidence to centralise?

Aim: To identify evidence for the minimum annual case load of open repairs of abdominal aortic aneurysms compatible with an acceptable perioperative mortality rate. Method: A PubMed search resulted in 137 references, sixteen articles with original data on volume and mortality not older than ten years were identified and selected for review Result: Three studies found no volume-mortality relationship when controlled for age, sex and medical risk. Six studies verified volume thresholds of 20 procedures per year or more. In seven studies hospital volumes of 7–17 elective abdominal aortic aneurysm (AAA) repairs per year were sufficient to reach a mortality rate of a national average or similar to that of higher volume centres. No studies were published on the minimum annual case-load of EndoVascular Aneurysm Repair (EVA R), or of a combination of EVAR and open repair. Conclusion: Recent studies in North America and in Europe indicate that 10–15 procedures annually can be sufficient to safely perform open AAA repairs. Centres regularly performing less should consider referral. Continuous monitoring and audit of risk-adjusted perioperative mortality rates should be practiced in all centres.

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.