Bilateral persistent sciatic arteries complicated by unilateral acute lower limb ischaemia.

We present a case of a middle-aged Caucasian woman who developed acuteon top of chronic limb ischaemia secondary to thrombotic occlusion of a persistent sciatic artery (PSA). Timely investigation and treatment were instituted resulting in a favourable outcome. PSA is an uncommon congenital, developmental, arterial anomaly which can cause serious lower limb complications such as acute or critical limb ischaemia and amputation. As this condition is rarely encountered in regular clinical practice, and has a limb-threatening potential, it is important to be aware of its cause, presentation and management. We describe the embryologic aetiology of PSA and discuss different investigation modalities and treatment options.

Cerebral monitoring in patients undergoing carotid endarterectomy using a triple assessment technique.

OBJECTIVES: Selective shunting during carotid endarterectomy (CEA) is advocated to reduce shunt related stroke. Cerebral monitoring is essential for temporary carotid shunting. Many techniques are available for cerebral monitoring, however, none is superior to monitoring the patient's neurological status (awake testing) while performing the procedure under local anaesthesia (LA). Cerebral oximetry (CO) and trans-cranial Doppler (TCD) has previously been used to show the adequacy of cerebral circulation in patients undergoing CEA. The aim of this study is to assess the reliability of CO and TCD in predicting the need for shunting compared to the awake testing. METHODS: Patients scheduled for CEA under LA were included. Patients converted to general anaesthesia (GA) and patients with no TCD window were excluded from the study. The Somanetics INVOS(®) CO was used for ipsilateral cerebral monitoring in all patients, in addition to TCD and awake testing. The percentage fall in CO regional oxygen saturation (rSO(2)), and decline in the mean flow velocity (FVm) in TCD following carotid artery clamping recorded. A drop in rSO(2) of ≥20% or FVm of ≥50% was considered an indicator of cerebral ischaemia that may predict the need for carotid shunting. Patients only shunted based on awake testing. RESULTS: Forty-nine patients underwent triple assessment. The median clamp time was 24 min. 8/49 patients (16.3%) needed carotid shunting based on awake testing. In this group, six patients had ≥20% drop in rSO(2), and ≥50% drop in FVm. However, two patients had a non-significant drop in both rSO(2) and FVm (false negative). In the non-shunted group (41/49), one patient had a significant drop in rSO(2) (false positive) while 10/41 patients had a >50% drop in FVm. This represents sensitivity of 75%, and specificity of 97.5% for CO compared to sensitivity of 75% and specificity of 75% for TCD in prediction of shunting. The positive predictive value and negative predictive value were 85.7 and 95.2%, respectively for CO, compared to 37.5 and 93.9% for TCD. CONCLUSIONS: TCD is less accurate than CO in predicting the need for carotid shunting during CEA. A combination of both methods does not add to the accuracy of detecting the need for carotid shunting.

Complications of open abdominal aortic surgery: the endovascular solution.

OBJECTIVES: Aorto-enteric fistulas (AEFs) and para-anastomotic aneurysms (PAAs) are uncommon complications of open aortic surgery (0.5-2.5%) and (0.2-15%), respectively. AEF if untreated is often fatal and surgical management is associated with mortality up to 90%. The risk of PAA rupture carries a mortality of 58%. We present our experience in ten patients with the endovascular treatment of these complications to define the role of endovascular repair in this high-risk group. METHODS: This is a retrospective review of patients presenting acutely with complications of open aortic surgery. From January 2003 to March 2006, ten patients, all males with a mean age of 73 years presented through the Accident and Emergency department and were assessed with contrast enhanced CT. Five patients presented with secondary AEFs. Three patients with PAAs. Another patient presented with a secondary mycotic aneurysm of the thoracic aorta following open repair of abdominal aortic aneurysm and finally a patient with a femoral pseudoaneurysm. The mean time from the original procedure to presentation was 50 months. All patients were offered endovascular management after stabilisation as they were deemed as high-risk surgical patients. RESULTS: No intra-procedural complications were recorded. The in-hospital 30-day mortality was 1 (10%) patient due to multiple organ failure. One patient died six months later due to an unrelated event. The average in-hospital stay was 5.4 days; median follow-up period was 28 months. All patients were repeatedly admitted after discharge due to septic episodes for which they received IV antibiotics. Repeated cultures for all patients were only positive on four occasions. CONCLUSION: Endovascular stent-graft repair of AEF and PAAs is a viable alternative to open surgery. It is likely to be associated with less mortality and morbidity and in-hospital stay. It should be considered as an alternative in high-risk patients. Persistence of the infection remains a problem, however, in our experience; it can be well controlled through long-term antibiotics.

Incidence of renal infarctions after endovascular AAA repair: relationship to infrarenal versus suprarenal fixation.

PURPOSE: To analyze the incidence and etiology of renal infarctions following endovascular abdominal aortic aneurysm (AAA) repair detected on computed tomography (CT) and determine any association with infrarenal versus suprarenal fixation. METHODS: Between August 1994 and October 2001, 663 patients (604 men; mean age 68.5 years, range 40-98) underwent endovascular AAA repair with predominately bifurcated (505, 77%) stent-grafts. About a third (202, 30%) of the devices were deployed in a suprarenal position. Contrast-enhanced CT scans were performed on days 10, 90, and 365 after operation and then annually. Two radiologists blinded to procedural details compared the preoperative and postoperative scans to identify renal infarctions from inadvertent renal artery occlusion by the endograft. Only patients with inadvertent infarctions were analyzed relative to endograft fixation position and stent-graft type. RESULTS: Mean follow-up was 37 months (range 0.1-75). Overall renal infarction rate was 11.9% (n=79); 23 (3.4%) patients suffered from limited, segmental infarction due to intentional covering of preoperatively diagnosed accessory renal arteries. Unintentional renal ischemia was identified in 56 (8.5%) patients. In this subgroup, 39 (19%) were observed in the 202 patients with suprarenal fixation versus 17 (3.7%) in the 461 stent-grafts positioned infrarenally (RR 3.35, 95% CI 2.20 to 5.04, p<0.00001). There was a significant correlation between the incidence of infarction and the device type (14.3% for modular grafts versus 5.6% for unibody designs, p=0.0002). Seventeen (2.6%) patients suffered from unilateral kidney loss, with dialysis required in 2 cases. Creatinine and urea showed no significant postoperative elevation in the overall patient population, but both levels were significantly (p<0.02) elevated in patients with complete unilateral renal infarcts. CONCLUSIONS: Transrenal fixation of aortic endografts had a 3-fold higher risk for renal infarction in this large patient population. There is no significant difference for specific endografts, but modular designs were associated with a higher rate of renal infarction. The need to occlude preoperatively diagnosed accessory renal arteries with an endograft should be considered a contraindication for current available devices.