Operative Factors Associated with the Development of New Brain Lesions During Awake Carotid Endarterectomy.

OBJECTIVES: The aim was to analyse a prospective, consecutive series of awake carotid endarterectomy (CEA) patients undergoing, when possible, pre- and postoperative diffusion-weighted magnetic resonance imaging brain scans (DWI). METHODS: All CEA patients from June 23, 2006, to January 13, 2012, were prospectively entered in the study. CEA was performed under regional cervical block. Only patients demonstrating shunt dependence were shunted. Before August 7, 2008, all longitudinal endarterectomy had been performed with a vein patch. From that date all CEA were eversions without a patch, except shunted patients who were vein patched. DWI was performed 2 days before and 5 days after (3 Tesla). Scans were reported by MRI-trained radiologists. Logistic regression analysis (LRA) identified predictive variables for MRI changes using backward stepwise elimination of variables with p > .05. RESULTS: There was a total of 295 consecutive CEA. There were no deaths but four clinical strokes (1.4 %); 89 excluded from DWI leaving 206; of these 27 (13%) developed new DWI lesions including four of 57 (7%) in the asymptomatic group and 23 of 149 (15%) symptomatic patients. Nineteen of the 206 (9.2%) were shunted. LRA showed that shunt dependence was highly associated with new DWI lesions: odds ratio (OR) 6.43; 95% confidence interval (CI) 2.3-17.9; p < .001. Both the vein patched, non-shunted group (OR .25; CI 0.09-0.72; p = .010) and the eversion (all non-shunted and all non-patched) group (OR 0.05; CI 0.01-0.22; p < .001) were associated with a low risk of new lesions, with the eversion group a lower risk than the patched group. CONCLUSIONS: One in every eight CEA patients developed new DWI lesions (rate doubled in symptomatic patients). Shunt dependence in conscious CEA patients is highly associated with the development of new DWI lesions compared with non-shunted patients. For non-shunted patients the new lesion risk is low, and in those patients the risk in the eversion group is lower than in the patched group.

Investigation of outcomes following recombinant activated FVII use for refractory bleeding during abdominal aortic aneurysm repair.

OBJECTIVE: To evaluate the outcomes following recombinant activated factor VII (rFVIIa) use during abdominal aortic aneurysms (AAA) repair. DESIGN: AAA patients were selected from the Australian and New Zealand Haemostasis Registry (ANZHR) who received off-licence rFVIIa to control critical bleeding. METHODS: Patient characteristics and outcomes were compared between responders (bleeding stopped/attenuated) and non-responders (bleeding continued) to rFVIIa, stratified by aneurysm status (ruptured (r-AAA) vs. non-ruptured (nr-AAA)). Patients were also scored using POSSUM (Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity) and Hardman Index mortality predictive models. RESULTS: In total, 77 AAA patients were included in the analysis. Approximately 73% (n = 56) of them had ruptured aneurysms and about 50% (n = 35/70 with known data) responded positively to rFVIIa. Eleven incidents of thromboembolic adverse events were reported in 9 patients (6 r-AAA and 3 nr-AAA). Responders in both ruptured and non-ruptured groups had significantly lower 28-day mortality than non-responders (r-AAA: 40% (10/25) vs. 92% (24/26); P < 0.001; nr-AAA: 30% (3/10) vs. 67% (6/9); P < 0.01). Mortality predictive models did not show any difference between overall observed and expected mortality in ANZHR patients. CONCLUSION: Patients who responded to rFVIIa had a lower mortality than those who did not respond to the treatment.

Factors affecting the shear bond strength of orthodontic brackets to porcelain.

The aim of this investigation was to establish a regime for orthodontic bonding to feldspathic porcelain, which ensures adequate bond strength (6-8 MPa) with minimal damage on debond and consisted of an ex vivo investigation measuring the effects of porcelain surface preparation and thermocycling on shear bond strength of orthodontic brackets. One-hundred-and-twenty feldspathic porcelain bonded crown surfaces were divided into 12 equally-sized groups to assess the effects of: (1) glaze removal, (2) application of hydrofluoric acid, phosphoric acid, or omission of acid treatment, and (3) silane priming upon the bond strength of premolar brackets bonded with Right-on (TM) composite resin adhesive. Specimens were subjected to thermocycling and then to shear debonding forces on an Instron machine. Removal of the porcelain glaze, or use of hydrofluoric acid, prior to bonding were found to be unnecessary to secure the target bond strength. Hydrofluoric acid application was associated with increased porcelain surface damage. Thermocycling caused a significant reduction in shear bond strength to porcelain (P < 0*001). The best regime for orthodontic bonding to feldspathic porcelain was to apply phosphoric acid for 60 seconds, and prime with silane prior to bonding. Usually the porcelain surfaces could be repolished. Refereed Paper

Overnight hospital stay for carotid endarterectomy.

OBJECTIVE: To determine if overnight hospital stay after carotid endarterectomy (CEA) is feasible and safe in the Australian setting. DESIGN: Case series with follow-up of 4-11 months (mean, 7 months). PATIENTS AND SETTING: All patients undergoing primary CEA performed by a vascular surgeon (BMB) between 30 May and 11 November 1996. Surgery was performed in one of four hospitals (a district general public hospital with about 400 beds and three private hospitals) in the Gosford area of New South Wales. INTERVENTIONS: CEA using regional anaesthesia and sedation, after diagnosis by duplex ultrasound scan, avoiding cerebral angiography and intensive care; planned discharge after overnight hospital stay; review at one month and duplex ultrasound scan at four months. OUTCOME MEASURES: Length of hospital stay and complications. RESULTS: 65 patients were admitted for CEA during the study period and 59 were scheduled for overnight stay (one had "re-do" surgery, two remained longer for reasons unrelated to carotid artery disease, and three had been scheduled before the change to overnight stay). 54 (92%) were discharged on the first postoperative day, and only three required readmission within 30 days (for urinary retention, angina and reperfusion syndrome). There were no deaths, no myocardial infarctions and no recognised instances of cerebral ischaemia during follow-up. CONCLUSION: CEA can be performed safely without cerebral angiography or intensive care, with over 90% expectation of a single night's stay in hospital.

Duplex scan surveillance of infra-inguinal bypass grafts: the case for selectivity.

A consecutive series of 270 non-reversed infra-inguinal saphenous vein bypass grafts performed by the same surgeon between January 1986 and January 1991 was reviewed. The series included 250 in situ and 20 translocated non-reversed grafts. The aims were to calculate the number of duplex scans that would have been required for surveillance, to determine the value of a non-selective prolonged scanning regimen and to identify subgroups requiring more (or less) intensive surveillance. Indications were for critical ischaemia in 194 patients, popliteal aneurysms in seven patients and incapacitating claudication in 69 patients. Patients were reviewed at 1 month and then at approximate 6 month intervals for symptoms and with resting and post-exercise ankle pressures. Primary patency of grafts placed to a popliteal distal anastomosis for critical ischaemia was 85% (s.e.m. 9.1%) at 3 years while secondary patency was 94% (s.e.m. 8.1%) at 4 years. Primary patency of grafts placed to a tibial artery or isolated popliteal segment was 68% (s.e.m. 8.4%) at 2 years while secondary patency was 76% (s.e.m. 9.9%) at 2.5 years. The difference in secondary patency between popliteal and tibial grafts was highly significant (P = 0.003). Tibial grafts required significantly more secondary early intervention than popliteal grafts. If recommended protocols for serial duplex scan (DS) surveillance had been followed, a minimum of 960 scans would have been required. If the tibial bypass group only had been monitored, 702 of these scans would have been avoided with a maximum loss of one popliteal graft and no limbs.(ABSTRACT TRUNCATED AT 250 WORDS)

In situ saphenous vein bypass: technical aspects and results.

A consecutive series of 113 non-reversed saphenous vein grafts is presented to illustrate the technique of the procedure, modifications necessary to overcome its disadvantages and the results obtainable using such methods. The grafts were performed between January 1986 and January 1989. During this period vein utilization rate rose to more than 90%. Eighty-one procedures were performed for limb salvage (mean preoperative ankle pressure index: 0.32 +/- 0.16). Cumulative patency at 30 months was 88% (+/- 4%) for the 81 limb salvage procedures and 89% (+/- 3%) for the total 113 grafts in the series. Twelve grafts permanently failed. No graft has failed after 2 months. Amputation was avoided in 88% of limb salvage procedures. Operative mortality was 4.4%, the average age of those dying being 77 years. Fifty-three in situ grafts were followed prospectively after accurate mapping of their valve lysis was performed during surgery. Patterns of valve lysis and technical aspects related to the performance of in situ grafts will be presented.

Elective aneurysm repair and the incidence of aortic rupture in an ageing population.

During the period January 1984-July 1988, 191 abdominal aortic aneurysms were encountered at Gosford District Hospital, NSW, a hospital that services an ageing population. These aneurysms were either repaired or found as the cause of death at post-mortem. During the study, the rate of elective repair rose from 0.25/month during the first 2 years to 3.67/month in the latter 2.5 years. The mortality for repair of non-ruptured aneurysms was 0.9% compared with 55% for ruptured aneurysms. The 15-fold increase in elective repair resulted in the 58% reduction in the incidence of abdominal aortic rupture from 1.87/month to 0.79/month. The mortality rate from known aneurysms fell from 46% to 14% in the final 2 years. Elective aneurysm repair reduces the incidence of and death from abdominal aortic rupture in an ageing population.

Endothelial cell harvest for seeding vascular prostheses: the influence of technique on cell function, viability, and number.

Direct seeding of endothelial cells onto synthetic vascular prostheses has become the subject of increasing surgical research during the last 5 to 7 years. The currently employed cell harvest techniques are inefficient, resulting in cell counts far below the number of cells calculated to be present on the original donor vein. We have compared two methods of enzymatic endothelial cell harvest: cannulation with flushing and eversion over a stainless steel rod. Harvested cells were plated onto tissue culture plastic and counted after 24 hours of incubation. The methods ensured that only those cells viable and functional enough to adhere to the plastic were being considered. Cells were identified as endothelial by immunohistochemical techniques applying antisera to factor VIII-related antigen. Segments of normal vein and of veins treated by each technique were viewed with a scanning electron microscope. Cannulation was the superior method, providing greater numbers of viable, functional cells. The eversion technique was unreliable and probably injurious to endothelial cells.

Maximizing the use of autogenous vein using the in situ (valve incision) technique.

Bypass grafting to vessels beyond the popliteal bifurcation is an established method for treating severe limb ischaemia. Failure rate is high, however, especially when prosthetic vascular substitutes have to be used. When left in situ, saphenous vein can be used down to much smaller diameters than would be possible with reversed vein. With this method, vein utilization of around 90% can be achieved with respective increases in patency and limb salvage. Our early results with 26 in situ grafts are presented. In two cases the presence of a suitable tributary of the saphenous vein allowed a 'bifurcated' or 'femorotibial' graft to be performed. All patients (17 males, nine females) were admitted with limb threatening ischaemia. Mean ankle pressure index was 0.29 (s.d. = 0.09), range 0.18-0.53. Average graft intra-operative flow rate measured 96 ml/min. Twenty grafts remain patent while six grafts have failed. In three of these failures, performed early in the series, the graft could not be made to function at the time of surgery. The mean postoperative ankle pressure index was 0.87 (s.d. = 0.19). Cumulative patency rate at 24 months is 74%. This rises to 83% if the three 'on table' failures are excluded. Five amputations were required; four as a result of graft failure and one despite a functioning graft. Four grafts clotted within 24 h but have remained patent following immediate thrombectomy. One patient required ligation of an arteriovenous fistula on the third postoperative day.

Brachio-cephalic revascularization from the intrathoracic aorta: use of a T-piece graft.

Ready made T-piece dacron grafts have been available for some time for use in axillo-bifemoral procedures. This report illustrates the use of such a graft in two cases of brachiocephalic revascularization from the intrathoracic aorta. In each case the aortic arch branches were severely diseased. The technique allows placement of the 8 mm diameter limb on the ascending aorta deep to the sternum, where, because of its lack of bulk, it can sit without compression. The 8 mm side piece can be manoeuvred to follow any direction required and avoids placement of an anastomosis in an otherwise awkward area. If required, a third limb can be sutured onto the proximal limb beyond the region where compression would occur.

Carotid endarterectomy in patients with actively changing neurological deficits--correlations with CT brain scans.

The place of carotid endarterectomy in patients with actively changing neurological deficits (ACND) is yet to be defined. This is a study of 15 patients with ACND who underwent carotid endarterectomy. All patients had demonstrable neurological deficits at the time of surgery. However no patient had severe devastating symptomatology or decreased levels of consciousness. Eight patients (Group I) were classified as stroke-in-evolution (SIE) according to Millikan. Seven other patients (Group II) were also unstable with deficits of recent onset but did not demonstrate a classical progressive or stepwise deterioration. Average internal carotid stenosis was 80% (range 50-90%). In each of the Group I patients CT scans of the brain demonstrated cerebral infarction in the area appropriate to the deficit. CT scans were performed in four of the Group II patients, two of whom showed cerebral infarction while two were normal. Seven of the eight Group I patients improved after surgery while one progressed to a completed stroke. Six of the seven Group II patients improved following surgery while one died on the third postoperative day. These results suggest an improved outlook with surgery when compared either with the natural history of SIE or with the results when anticoagulants alone are used.

Cystic adventitial disease of the popliteal artery: a report of two cases and a review of the literature.

Cystic adventitial disease is a rare condition affecting the wall of certain major arteries. The case histories of two patients presenting to the Royal North Shore Hospital are reviewed. Both patients were young men who presented with unilateral incapacitating calf claudication of sudden onset. Lower limb arteriography on each affected leg revealed a peculiar irregularity of the popliteal artery. Each patient had the popliteal artery explored and similar findings were revealed viz: an extensive cyclic lesion occupying the adventitial layer of the popliteal artery. The cysts were found to contain mucoid material. It was not necessary to enter the arterial lumen in either case. As far as can be established both patients have remained asymptomatic after the simple procedure of evacuating mucoid material from the cysts.