Local Haemodynamic Changes During Carotid Endarterectomy—The Influence on Cerebral Oxygenation

AbstractObjectives. To characterize carotid bifurcation haemodynamics and cerebral oxygenation during clamping and at reperfusion after carotid endarterectomy (CEA).Materials and methods. Sixty-two patients with a symptomatic high-grade stenosis of the internal carotid artery (ICA), who underwent CEA under general anaesthesia, were studied prospectively. Measurements of stump-pressure, volume flow (transit time flowmetry) and changes in cerebral oxygenation (near-infrared spectroscopy (NIRS)) were performed. Selective shunting was based on stump pressure only.Results. Stump pressure correlated with both ICA flow before clamping (r=0.45; p=0.03) and changes in cerebral oxygenation (rSO2) during clamping (r=0.61; p=0.002), the latter was reversed by shunt placement. ICA flow before clamping also correlated with changes in rSO2 during clamping (r=0.41; p=0.01).Conclusion. Measurements with transit time flowmetry and cerebral oximetry are technically easy and help to determine the need for selective shunting during CEA. High ICA flow before clamping in combination with a low stump pressure usually indicates the need for a shunt. Volume flow measurements may also be useful in the quality assessment of the CEA

Arterio-ureteral Fistula – a Systematic Review

AbstractObjective: to review published reports on arterio-ureteral fistula. Method: literature search. Results: eighty cases were identified. Primary fistulas were mainly seen in combination with aortoiliac aneurysmal disease. Secondary fistulas were seen after pelvic cancer surgery, often with radiation, fibrosis and ureteral stenting or after vascular surgery with synthetic grafting. The dominating symptom is massive haematuria, often with circulatory impairment. The clue to a rapid and correct diagnosis is a high degree of suspicion. Most frequently diagnosis has been obtained through angiography or pyelography. When there is a ureteral stent manipulation it will often provoke bleeding and lead to diagnosis. The fistula must be excluded and a vascular reconstruction made. Most frequently this has been obtained through occlusion of the fistula and an extra-anatomic reconstruction (femoro-femoral crossover). Recently stent-grafting has been successfully used but follow-up is short. Conclusion: arterio-ureteral fistula is rare and should be suspected in patients with complicated pelvic surgery and massive haematuria, especially where rigid ureteral stents have been placed

The effect of biliary decompression on bacterial translocation in jaundiced rats

Patients with obstructive jaundice are prone to septic complications after biliary tract operations. Restoring bile flow to the intestine may help to decrease the complication rate. The present study is aimed at evaluating the effect of biliary decompression on bacterial translocation in jaundiced rats. Sixty-six male Sprague-Dawley rats were randomly allocated to six groups subjected to common bile duct ligation (CBDL) and transection (groups 2-6) or sham operation (group 1). In groups 1 and 2 the incidence of enteric bacterial translocation was determined 2 weeks after sham operation or CBDL. In groups 3-6, biliary decompression was achieved by performing a choledochoduodenostomy after 2 weeks of biliary decompression. Bacterial translocation was then studied 1, 2, 3 and 5 weeks following biliary decompression. The rate of bacterial translocation to mesenteric lymph nodes in obstructive jaundice was significantly higher as compared with controls and decreased with time to nil three weeks following biliary decompression. The incidence of bacterial translocation was closely correlated (r = 0.844; p = 0.034) with serum alkaline phosphatase activity and seemed to fit with the morphological changes noted in the small intestine. The decrease in bacterial translocation, however, lags behind the recovery of liver function as measured by routine liver function tests and antipyrine clearance. Obstructive jaundice thus promotes bacterial translocation in the rat. Biliary decompression gradually decreases the rate of bacterial translocation

Experimental evaluation of small diameter synthetic arterial grafts

Platelets labelled with Indium-111 were used to examine the in vivo thrombogenicity of different vascular grafts. The deposition of platelets in two partly different kinds of umbilical vein grafts, double velour Dacron grafts and double velour Dacron grafts with internal collagen was studied as a function of time. The grafts were inserted end to side in the femoral artery of pigs and then imaged for 120 minutes. Platelet distribution was also studied by in vitro static imaging. No difference was seen between the different umbilical vein grafts. The double velour grafts accumulated more platelets, the platelets mainly located in the midportion of the graft. The collagen-impregnated grafts occluded within 45 minute

10-year stroke prevention after successful carotid endarterectomy for asymptomatic stenosis (ACST-1) : A multicentre randomised trial

Background If carotid artery narrowing remains asymptomatic (ie, has caused no recent stroke or other neurological symptoms), successful carotid endarterectomy (CEA) reduces stroke incidence for some years. We assessed the long-term effects of successful CEA. Methods Between 1993 and 2003, 3120 asymptomatic patients from 126 centres in 30 countries were allocated equally, by blinded minimised randomisation, to immediate CEA (median delay 1 month, IQR 0·3-2·5) or to indefinite deferral of any carotid procedure, and were followed up until death or for a median among survivors of 9 years (IQR 6-11). The primary outcomes were perioperative mortality and morbidity (death or stroke within 30 days) and non-perioperative stroke. Kaplan-Meier percentages and logrank p values are from intention-to-treat analyses. This study is registered, number ISRCTN26156392. Findings 1560 patients were allocated immediate CEA versus 1560 allocated deferral of any carotid procedure. The proportions operated on while still asymptomatic were 89·7 versus 4·8 at 1 year (and 92·1 vs 16·5 at 5 years). Perioperative risk of stroke or death within 30 days was 3·0 (95 CI 2·4-3·9; 26 non-disabling strokes plus 34 disabling or fatal perioperative events in 1979 CEAs). Excluding perioperative events and non-stroke mortality, stroke risks (immediate vs deferred CEA) were 4·1 versus 10·0 at 5 years (gain 5·9, 95 CI 4·0-7·8) and 10·8 versus 16·9 at 10 years (gain 6·1, 2·7-9·4); ratio of stroke incidence rates 0·54, 95 CI 0·43-0·68, p<0·0001. 62 versus 104 had a disabling or fatal stroke, and 37 versus 84 others had a non-disabling stroke. Combining perioperative events and strokes, net risks were 6·9 versus 10·9 at 5 years (gain 4·1, 2·0-6·2) and 13·4 versus 17·9 at 10 years (gain 4·6, 1·2-7·9). Medication was similar in both groups; throughout the study, most were on antithrombotic and antihypertensive therapy. Net benefits were significant both for those on lipid-lowering therapy and for those not, and both for men and for women up to 75 years of age at entry (although not for older patients). Interpretation Successful CEA for asymptomatic patients younger than 75 years of age reduces 10-year stroke risks. Half this reduction is in disabling or fatal strokes. Net benefit in future patients will depend on their risks from unoperated carotid lesions (which will be reduced by medication), on future surgical risks (which might differ from those in trials), and on whether life expectancy exceeds 10 years. Funding UK Medical Research Council, BUPA Foundation, Stroke Association