Efficacy and durability of the chimney graft technique in urgent and complex thoracic endovascular aortic repair.

This study reports the early and midterm to long-term experience of chimney grafts (CGs) in urgent endovascular repair of complex lesions in the thoracic aorta

Reduced pulsatile wall motion of abdominal aortic aneurysms after endovascular repair

AbstractPurpose: The reduced size of abdominal aortic aneurysms (AAAs) after endovascular repair suggests lowered intraaneurysmal pressure. In the presence of endoleaks, the size is not decreased. Although postoperative intraaneurysmal pressure is difficult to record, the pulsatile wall motion (PWM) of aneurysms can be measured noninvasively. The aim of this study was to assess the PWM of AAAs before and after endovascular repair and to relate the change in the PWM to aneurysmal size and presence of endoleaks. Methods: Forty-seven patients underwent endovascular repair of an AAA. The aneurysm diameter and PWM were measured with the use of ultrasonic echo-tracking scans preoperatively; at 1, 3, and 6 months; and thereafter biannually. Fifteen aneurysms developed endoleaks, whereas 32 were completely excluded. The leaks were characterized with the use of computed tomographic scanning and angiography. Median follow-up was 12 months (interquartile range, 5 to 24 months). Results: The preoperative PWM of the aneurysms was 1.0 mm (range, 0.8 to 1.3 mm). After complete endovascular exclusion, the PWM was 25% (range, 16% to 37%) of the preoperative value (p < 0.001), and aneurysm diameter decreased by 8 mm (range, 6 to 14 mm) (p < 0.001). After 18 months, no further diameter reduction occurred. In three patients without endoleaks but with enlarging aneurysms, the postoperative PWM showed less reduction (p < 0.05). Aneurysms with endoleaks showed no diameter decrease, and the postoperative PWM was 50% higher than that in the totally excluded cases (p < 0.01). In five patients with transient endoleaks, the PWM was reduced after leakage ceased (p < 0.05). Leaks of various sources displayed similar PWM. Conclusion: The size and PWM of aneurysms are reduced after endovascular repair. The diameter reduction may cease after 1.5 years. Endoleaks are associated with higher PWM than expected. Pressure may be transmitted without evidence of leaks. (J Vasc Surg 1998;27:624-31.

Changes in aneurysm morphology and stent-graft configuration after endovascular repair of aneurysms of the descending thoracic aorta

AbstractObjective: We sought to study changes in morphology and stent-graft configuration of descending thoracic aortic aneurysms after endovascular repair. Methods: Twenty-three patients treated with custom-made stent-grafts were studied. The stent-graft consisted of continuous, stainless-steel Z stents mounted within a polyester graft. In the last 11 cases the stents were interconnected with 3 longitudinal wires. Contrast-enhanced spiral computed tomography was performed preoperatively and at 1, 3, and every 6 months postoperatively. Angiography was used preoperatively and at 1-year follow-up. Proximal and distal necks were assessed for diameter and length. Aneurysm diameter, endoleaks, stent-graft migration, and changes in stent-graft configuration were evaluated. Results: During follow-up (median, 18 months; range, 1-48 months), excluded aneurysms decreased in diameter by 4 mm (0.5-10 mm, P =.0018). Endoleaks prevented size decrease. Five patients displayed neck dilatation, 4 at both the proximal and distal fixation sites and 1 only distally. In 7 (30%) patients there was proximal migration of the distal end of the stent-graft. Three (13%) patients displayed both distal migration of the proximal end of the stent-graft and proximal migration of the distal end of the stent-graft. There was a significant correlation between stent-graft kinking and appearance of proximal or distal stent-graft migration (P =.05 and P =.0007, respectively). In no case did the migration lead to appearance of an endoleak before intervention was performed. Conclusion: Excluded descending thoracic aortic aneurysms decrease in size on midterm follow-up. A subgroup of patients prone to neck dilatation might exist. A combination of neck dilatation and vector forces acting on stent-grafts in the tortuous thoracic aorta might lead to stent-graft migration.J Thorac Cardiovasc Surg 2001;122:47-5

Chimney grafts preserve visceral flow and allow safe stenting of juxtarenal aortic occlusion

ObjectiveChimney grafts have proven useful for urgent endovascular repair of juxtarenal aortic aneurysms. Stenting of juxtarenal aortic occlusive disease is not routinely advocated due to the risk of visceral artery obstruction. We report on the potential applicability of chimney grafts in 10 patients with juxtarenal aortic stenosis or occlusion. To our best knowledge, chimney grafts have not been applied previously in this challenging setting.MethodsTen high-risk female patients (mean age, 68 years) with severe stenosis or occlusion of the aorta at the level of the visceral arteries were offered stenting. “Chimney” stents or stent grafts (20-40 mm long) were implanted from a brachial approach into visceral arteries that needed to be covered by the aortic stent. The chimney stents were then temporarily obstructed by balloon catheters to prevent visceral embolization until the aortic stent or stent graft was deployed.ResultsAll procedures were technically successful, and patency was obtained in all visceral arteries and the aorta without distal embolization. One patient died after 9 days of acute heart failure. The nine surviving patients presented no complications, and all stented vessels remained patent at up to 6 years. Another patient died after 5.5 years due to lung cancer. All three patients with renal impairment have improved renal function, and a reduction in antihypertensive medication has been possible.ConclusionsChimney grafts may allow stenting of juxtarenal aortic occlusive disease by protecting the patency of visceral arteries. Further evaluation with more patients and longer follow-up is required

Intra-aneurysm sac pressure measurements after endovascular aneurysm repair: differences between shrinking, unchanged, and expanding aneurysms with and without endoleaks

AbstractObjectiveOur objective was to study intra-aneurysm pressure after endovascular aneurysm repair (EVAR) in shrinking, unchanged, and expanding abdominal aortic aneurysms (AAAs) with and without endoleaks.MethodsDirect intra-aneurysm sac pressure measurement (DISP) by percutaneous translumbar puncture of the AAA under fluoroscopic guidance was performed 46 times during the follow-up of 37 patients (30 men; median age, 73 years [range, 58-82 years]; AAA diameter: median, 60 mm [range, 48-84 mm]). Three patients were included in two different groups because DISP was performed more than once with different indications. Tip-pressure sensors mounted on 0.014-inch guidewires were used for simultaneous measurement of systemic and AAA sac pressures. Mean pressure index (MPI) was calculated as the percentage of mean intra-aneurysm pressure relative to the simultaneous mean intra-aortic pressure.ResultsMedian MPI was 19% in shrinking (11 patients), 30% in unchanged (10 patients), and 59% in expanding (9 patients) aneurysms without endoleaks. Pulse pressure was also higher in expanding (10 mm Hg) compared with shrinking (2 mm Hg; P < .0001) AAAs. Four of the nine patients with expanding AAAs underwent five repeated DISPs later in the follow-up, and MPIs were consistently elevated. Seven of the 10 patients with unchanged AAAs without endoleaks underwent further computed tomography follow-up after DISP; 2 expanded (MPI, 47%-63%), 4 shrank (MPI, 21%-30%), and 1 remained unchanged (MPI, 14%). Type II endoleaks (6 patients, 7 DISPs) were associated with wide range of MPI (22%-92%). Successful endoleak embolization (n = 4) resulted in pressure reduction.ConclusionsIntra-aneurysm sac pressure measurement is an important adjunctive for EVAR evaluation, possibly allowing early detection of failures. High pressure is associated with AAA expansion and low pressure with shrinkage. Type II endoleaks can be responsible for AAA pressurization, and successful embolization appears to result in pressure reduction

Persistent collateral perfusion of abdominal aortic aneurysm after endovascular repair does not lead to progressive change in aneurysm diameter

AbstractPurpose: To differentiate between the phenomenon of collateral perfusion from a side branch versus graft-related endoleaks after endovascular repair of abdominal aortic aneurysms (AAA), with respect to aneurysm size and prognosis. Methods: We successfully treated 64 AAA patients with endovascular grafting. We followed all the patients postoperatively with spiral computed tomography at one, three, six and 12 months, and biannually thereafter. We measured aneurysm diameters preoperatively and postoperatively. We calculated preoperatively the relation of maximum aortic diameter (D) to the thrombus-free lumen diameter (L) expressed as an L/D ratio. Median follow-up was 15 months. Results: Sixteen patients had collateral perfusion during follow-up. We successfully treated two patients with embolization. One patient showed resolution of collateral perfusion after we stopped warfarin treatment. Two patients died of unrelated causes during follow-up. One patient was converted to surgical treatment, and two patients showed spontaneous resolution of their collateral perfusion. The group of patients with perfusion showed no statistically significant change of their aortic diameter on follow-up. The group of patients without perfusion showed a median decrease in aortic diameter of 8mm (p < 0.0001) at 18 months postoperatively. The group of patients with perfusion had significantly less thrombus in their aneurysm sac preoperatively than the group without perfusion, as expressed by the L/D ratio (mean L/D 0,61 versus 0,78, respectively; p = 0.0021.) Conclusion: There was no significant increase in aortic diameter on an average 18 months postoperatively despite persistent collateral perfusion. This may indicate a halted disease progression in the short term. Embolization of collateral vessels is associated with risk of paraplegia. We recommend a conservative approach with close observation if aneurysm diameter is stable. (J Vasc Surg 1998;28:242-9.

Time-related anticoagulation after regional and systemic administration of heparin in patients undergoing aortoiliac surgery

Heparin anticoagulation during cardiovascular surgical procedures remains poorly investigated and understood. The objective of this investigation was to assess the effectiveness of three methods of heparin administration. Heparin sulfate (75 IU/kg) administered to patients undergoing aortoiliac surgery was randomised to one of three methods: Group I (n = 9) heparin was injected into a central venous line 5 minutes before infrarenal aortic clamping; Group II (n = 9) heparin was injected into the distal aneurysm immediately after infrarenal aortic clamping; and Group III (n = 8) heparin was injected into a central venous line immediately after infrarenal aortic clamping. Blood samples were analysed for anticoagulant activity from both the upper and lower extremities at 5, 15, 30, 60, and 120 minutes after heparin administration. Anticoagulation, as measured by aPTT, antifactor Xa levels, and ACT, was achieved in all three groups by 5 minutes, but initially with lower heparin activity (measured as antifactor Xa) in the upper extremity (Group II) and lower extremity (Group III), respectively. These differences were also evident in ACT and aPTT determinations. Intravenous heparin administration prior to aortic cross-clamping achieves excellent anticoagulation (anti-factor Xa ~ 1 U/ml) in both upper and lower extremities after 5 minutes. With regional administration, rapid heparin redistribution occurs, but it takes longer to achieve the same level of anticoagulation distant from the site of administration. Nevertheless, from a practical perspective the method of administration does not appear to have a great influence on the eventual achievement of adequate anticoagulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31338/1/0000248.pd

Endovascular repair of descending thoracic aortic aneurysms: an early experience with intermediate-term follow-up

AbstractPurpose: The purpose of this study was to report an initial experience with the endovascular repair of descending thoracic aortic aneurysm. Complications and intermediate-term morphologic changes were identified with the intent of altering patient selection and device design. Methods: Endografts were placed into 25 patients at high-risk for conventional surgical repair over a 3 ½–year period. Devices were customized on the basis of preoperative imaging information. Follow-up computed tomography scans were obtained at 1, 3, 6, and 12 months and yearly thereafter. Additional interventions occurred in the setting of endoleaks, migration, and aneurysm growth. Results: The overall 30-day mortality rate was 20% (12.5% for elective cases; 33% for emergent cases). There were 3 conversions to open repair. Neurologic deficits developed in 3 patients; 1 insult resulted in permanent paraplegia. Neurologic deficits were associated with longer endografts (P = .019). Three endoleaks required treatment, and 1 fatal rupture of the thoracic aneurysm treated occurred 6 months after the initial repair. Migrations were detected in 4 patients. The maximal aneurysm size decreased yearly by 9.15% (P = .01) or by 13.5% (P = .0005) if patients with endoleaks (n = 3 patients) were excluded. Both the proximal and distal neck dilated slightly over the course of follow-up (P = .019 and P = .001, respectively). The length of the proximal neck was a significant predictor of the risk for endoleakage (P = .02). Conclusion: The treatment of descending thoracic aortic aneurysms with an endovascular approach is feasible and may, in some patients, offer the best means of therapy. Early complications were primarily related to device design and patient selection. All aneurysms without endoleaks decreased in size after treatment. Late complications were associated with changing aneurysm morphologic features and device migration. The morphologic changes remain somewhat unpredictable; however, alterations in device design may result in improved fixation and more durable aneurysm exclusion. (J Vasc Surg 2000;31:147-56.

Norske og svenske blåskjell til Europa: sluttrapport. Geir Olav Knappe (red.)

Prosjektet startet gjennom norsk søknad datert 30. mars 2004 og norsk tilsagn datert 14.11.2005. Prosjektet var planlagt gjennomført i prosjektperioden 01.08.2005 - 31.12.2006. Etter søknad ble prosjektperioden forlenget til 30.06.2007. Denne rapporten inneholder resultatet fra en rekke arbeidsfelt som prosjektmedarbeiderne har vært innom, og hvor noen er obligatoriske i InterReg-sammenheng. Følgende fire elementer i arbeidet som er gjort kommer norsk og svensk skjellnæring til stor nytte framover: 1. En omfattende markedsundersøkelse, i tillegg til to markedsrapporter. Gjennom disse avdekkes det europeiske skjellmarkedet med en detaljrikdom som svært få tidligere har hatt kunnskap om. 2. En økonomisk analyse av norsk skjellnæring som dokumenterer de økonomiske fakta for næringa. 3. På svensk side har prosjektarbeidet munnet ut i en etablering av en produsentorganisasjon (PO), etter europeisk modell innenfor EU. 4. Arbeidet har medført et utstrakt samarbeid mellom aktører på norsk og svensk side. Dette har dannet er et godt grunnlag for videre samarbeid, både innen produksjon og markedsføring og salg av blåskjell på det europeiske markedet. Rapporten er to-delt. Hovedrapporten inneholder en oppsummering og avrapportering av prosjektet.Interreg IIIA, Vattenbrukarnas Riksförbund, Vattenbrukarnas Servicebolag AB, Høgskolen i Nord-Trøndelag, avdeling Namsos, Namdalshagen A