Computed tomographic angiographic imaging of abdominal aortic aneurysms: implications for transfemoral endovascular aneurysm management

PURPOSE: To describe anatomic features pertinent to patient selection and graft design for transfemoral endovascular aneurysm management (TEAM) of the infrarenal aorta using computed tomographic (CT) angiography. METHODS: A prospective noncomparative analysis of 102 spiral CT scans of the abdominal aorta of patients with abdominal aortic aneurysms was performed. From the original CT data set, slices were reconstructed perpendicular to the vessel axis (central lumen line) at a 10 mm interval. In these reconstructed slices, diameter measurements were performed. Vessel length was measured along the central lumen line. In each patient possibilities for TEAM were analyzed. RESULTS: Because of technical reasons, 36 scans were excluded from the analysis. Of the remaining 66 patients, 18 could potentially be treated with a bifurcated endovascular device. The infrarenal aortic diameter-to-iliac artery diameter ratio was less than 2 in most patients. The vessel segments judged to be adequate for endovascular graft anchoring had a noncylindrical shape in the majority of cases. CONCLUSION: Only a minority of patients with abdominal aortic aneurysms can at this stage be treated with an endovascular graft. The ideal endovascular graft should be a combination of rigid and flexible components. The proximal and distal attachment systems should have some flexibility with an intrinsic maximum diameter while the midsection of the graft can be relatively rigi

Cerebral Blood Flow in Relation to Contralateral Carotid Disease an MRA and TCD Study

AbstractObjective: to describe redistribution of cerebral blood flow in patients with severe internal carotid artery (ICA) stenoses in relation to contralateral ICA disease. Methods: sixty-six patients scheduled for carotid endarterectomy (CEA) were grouped according to severity of contralateral stenosis (<30% [group I]; 30–69% [group II]; 70–99% [group III]; occlusion [group IV]. Transcranial Doppler (TCD) and magnetic resonance angiography (MRA) investigations were performed preoperatively. Results: TCD demonstrated a reversed flow in the contralateral anterior cerebral artery (A1segment) and ophthalmic artery in three-quarters of group IV patients (p <0.0001). Group IV patients also exhibited decreased blood flow velocity in the contralateral middle cerebral artery (p =0.001). MRA showed increased ipsilateral ICA and basilar artery (BA) blood flow volumes (Q-flows) in group IV patients when compared to the other groups (p <0.001). No changes in total Q-flow (ICAs+BA) were found. Conclusions: in patients considered for CEA, the severity of the contralateral ICA disease is an important determinant of the pattern of blood flow redistribution through the anterior communicating pathway and ophthalmic artery. Significant flow redistribution through the posterior communicating pathway occurs especially in patients with contralateral ICA occlusion

Outcome After Occlusion of Infrainguinal Bypasses in the Dutch BOA Study: Comparison of Amputation Rate in Venous and Prosthetic Grafts

AbstractObjectiveTo compare the consequences of occlusion of infrainguinal venous and prosthetic grafts.MethodsIn total, 2690 patients were included in the Dutch BOA study, a multicenter randomised trial that compared the effectiveness of oral anticoagulants with aspirin in the prevention of infrainguinal bypass graft occlusion. Two thousand four hundred and four patients received a femoropopliteal or femorodistal bypass with a venous (64%) or prosthetic (36%) graft. The incidence of occlusion and amputation was calculated according to graft material and the incidence of amputation after occlusion was compared with Cox regression to adjust for differences in prognostic factors.ResultsThe indication for operation was claudication in 51%, rest pain in 20% and tissue loss in 28% of patients. The mean follow up was 21 months.After venous bypass grafting 171 (15%) femoropopliteal and 96 (24%) femorodistal grafts occluded. After prosthetic bypass grafting 234 (30%) femoropopliteal and 25 (38%) femorodistal grafts occluded. Patients with occlusions in the venous group had more severe ischemia, less runoff vessels and were older than the patients with prosthetic grafts. In the venous occlusion group 54 (20%) amputations were performed compared to 42 (16%) in the prosthetic occlusion group; crude hazard ratio 1.17 (95% CI 0.78–1.75). After adjustment for above mentioned differences in patient characteristics the hazard ratio was 0.86 (95% CI 0.56–1.32).ConclusionThe need for amputation after occlusion is not influenced by graft material in infrainguinal bypass surgery

The role of infrarenal aortic side branches in the pathogenesis of endoleaks after endovascular aneurysm repair

Aim:to investigate the relation between the number of preoperative patent side branches and the presence or absence of postoperative endoleaks, and to study the fate of patent branches after operation.Patients and Methods:thirty consecutive patients were included. Cine mode viewing of axial CT angiography images was applied to detect infrarenal aortic side branches. The position of side branches relative to the renal arteries, branch patency and run-off pathways were studied.Results:a total of 160 patent side branches were found. All patients had two or more patent side branches. A patent inferior mesenteric artery was found in 22/30 patients (73%). Postoperative CT scans revealed major endoleaks in five patients (16%) and minor endoleaks in eight (27%). There was no significant difference in the number of preoperative patent side branches in patients with a completely thrombosed aneurysm sac (five; range 2–8) compared to patients with postoperative endoleaks (six; range 3–9; p = 0.12). Backbleeding from patent side branches as the sole cause of endoleak was seen in one patient only (3.3%).Conclusion:postoperative endoleaks are not related to the number of preoperative patent side branches. In patients without endoleaks, contrast enhancement of side branches was repeatedly seen in the vicinity of the aneurysm wall. Although close follow-up of these branches is warranted, they did not affect the outcome of endovascular aneurysm repair

Recognising stroke prone patients with a poor collateral circulation

The prognosis in carotid disease is extremely variable and is influenced by the availability of collateral circulation. This study investigates the possibility of recognising patients with a poor collateral potential by using non-invasive tests. Preoperative OPG and EEG were compared with intraoperative EEG during test clamping in 208 carotid endarterectomies. Clamping ischaemia occurred in 29 patients (14%). Preoperative EEG had a sensitivity of 62% and a specificity of 82%. OPG showed a sensitivity of 96% and a specificity of 54%. Combined OPG and EEG resulted in a sensitivity of 93% and a specificity of 73%. Both tests are safe and easy to perform and interpret. These techniques can be used to identify those patients with carotid stenosis who have an increased risk of stroke due to a poor collateral circulation and may help to refine the indications for carotid endarterectomy

Flow redistribution in the major cerebral arteries after carotid endarterectomy: a study with transcranial Doppler scan.

Contains fulltext : 186812.pdf (publisher's version ) (Closed access)PURPOSE: This open single-center prospective study aimed to determine the redistribution of blood flow within the circle of Willis and through collateral pathways after carotid endarterectomy. Blood flow velocity and flow direction in the major cerebral arteries were determined, both at rest and during CO(2) inhalation. METHODS: Carotid endarterectomy was performed in 148 patients with a 70% or greater diameter stenosis of the internal carotid artery while patients were under general anesthesia. Arteriotomy closure was done with a venous patch. Selective shunting was performed with an electroencephalogram. Baseline blood flow velocity of the basal cerebral arteries was measured by means of transcranial Doppler sonography preoperatively (within 1 week before surgery) and 3 months postoperatively. At the same times, cerebrovascular reactivity was calculated during CO(2) inhalation insonating both middle cerebral arteries. RESULTS: Baseline blood flow velocity in the ipsilateral middle cerebral artery hardly changed 3 months postoperatively, but there was a considerable redistribution of flow in the circle of Willis. This was characterized by a decrease in contribution from the contralateral hemisphere through the anterior communicating artery, reduced cerebropetal flow rates in the ophthalmic artery, and smaller contribution of the posterior collateral sources. The CO(2) reactivity on the side of surgery increased in all patients. In patients with a contralateral occlusion, CO(2) reactivity increased on both sides. The redistribution of flow was most pronounced in patients who needed intraoperative shunting and in patients with a contralateral internal carotid artery occlusion. CONCLUSION: After carotid endarterectomy, flow redistribution, as expressed by changes in blood flow velocity values, occurs in the circle of Willis. The contribution of collateral sources is diminished, and the CO(2) reactivity increases, both of which reflect improvement of the hemodynamic condition. The most improvement occurs in patients with contralateral occlusion