Katarina Björses

Fenestrated endovascular repair for juxtarenal aortic pathology.

OBJECTIVE To evaluate the outcomes after fenestrated endovascular aortic repair (f-EVAR) in a tertiary European referral center. METHODS All patients treated with commercially available custom-made f-EVAR between September 2002 and June 2007 were prospectively enrolled in a computerized database including co-morbidities and aneurysm morphology. Patients were retrospectively analyzed. Follow-up consisted of clinical examinations and computed tomography (CT) scanning. RESULTS A total of 54 patients were included in this study. Median age was 72 (interquartile range [IQR] 68-76) years and 85% were men. Median preoperative aneurysm diameter was 60 (53-66) mm. One hundred thirty-four vessels were targeted (43 scallops, 91 fenestrations) and 96 stents were placed (69 bare, 27 covered). Target vessel catheterization was achieved in 98% of cases. Two patients (3.7%) died within 30 days, 1 from trash embolization and multiorgan failure and 1 from retroperitoneal bleeding caused by a renal artery perforation. Three type I endoleaks occurred intraoperatively, two sealed pre-discharge and one was treated with a Palmaz stent (Cordis, Miami Lakes, Fla) on postoperative day 4. Thirteen patients had type II endoleaks, and 2 required treatment. The median clinical follow-up was 25 (12-32) months with median CT follow-up of 22 (4-26) months. Aneurysm diameter decreased >or=5 mm in 47%, was unchanged in 50%, and increased >or=5 mm in 3% of patients at 1 year. There were three type II endoleaks at 1-year follow-up, one of which was successfully treated after 19 months due to aneurysm growth. Ninety-six percent of target vessels remained patent during the study period and all occlusions occurred within the first year of follow-up. Five target vessels occluded (2 renal arteries [RAs] and 3 superior mesenteric arteries [SMAs]) without symptoms during follow-up and successful reinterventions were done on 2 stenosed RAs. Three patients suffered creatinine increase but none needed dialysis. One late aneurysm-related death occurred due to massive bleeding during redo surgery for infection. CONCLUSION Despite complex anatomy or severe comorbidities in these patients f-EVAR has acceptable short- and midterm results in this series which includes a learning curve and offers a valid treatment alternative to patients unsuitable for standard EVAR or open repair.

Kissingstents in the Aortic Bifurcation - a Valid Reconstruction for Aorto-iliac Occlusive Disease.

OBJECTIVE To evaluate outcome and patency predicting factors of kissingstent treatment for aorto iliac occlusive disease (AIOD). METHODS Patients treated with kissingstents for AOID between 1995 and 2004 at a tertiary referral center were identified through local databases. Chart review and preoperative images were used for TASC and Fontaine classification. Follow-up consisted of clinical exams, ABI and/or duplex. Patency rates were estimated by Kaplan-Meier analysis, and Cox multivariate regression was used to determine factors associated with patency. RESULTS 173 consecutive patients (46% male, mean 64 years) were identified. TASC distribution was: A 15%, B 34%, C 10%, D 41%. Mean follow-up was 36 months (range: 1-144). 30-day mortality was 1% (2 patients), and 1-year survival was 91% (157 patients). 2 patients underwent late, open conversion and 13 patients suffered minor puncture site complications. Primary, assisted primary and secondary patency was: 97%, 99% and 100%, and 83%, 90% and 95% at twelve and 36 months respectively. There was no significant difference in patency between the TASC groups. Patency was significantly worse for patients in Fontaine class III. CONCLUSIONS Aortoiliac kissing stents is a valid alternative to open repair for TASC A-D lesions. The procedure has low mortality and morbidity and good patency at 3 years.

Topical Haemostatics in Renal Trauma—An Evaluation of Four Different Substances in an Experimental Setting

BACKGROUND Damage control is valuable in hemodynamically unstable trauma patients. To improve the hemostasis of packing, topical hemostatic agents have been suggested. The effects of such agents are unclear in trauma situations. The purpose of this study was to investigate the hemostatic capacity, and the stability of the hemostatic clot, of four substances with different mode of action in an experimental traumatic bleeding model. METHODS A standardized heminefrectomy was performed in 180 heparinized and normotensive Sprauge-Dawley rats. Four different substances were studied (separately and in combinations) in a randomized fashion: gelatin (sponge and matrix), bovine thrombin, freeze-dried recombinant factor VIIa (rFVIIa), and microporous polysaccharide hemospheres. Eight treatment groups (15 animals/group) were considered, primary endpoint was hemostasis within 20 minutes of observation. The effective treatment groups were evaluated in a second set in the same experimental model, but with a prolonged observation time after hemostasis (60 minutes) to control the stability of the clot. RESULTS Those animals treated with gelatin in the comparative study, with and without thrombin or rFVIIa, obtained hemostasis. Thrombin and rFVIIa alone did not have any hemostatic capacity. Only 20% to 25% of the animals obtained hemostasis with microporous polysaccharide hemospheres alone or in combination with rFVIIa. In the prolonged observation study, gelatin alone and in combination with thrombin or rFVIIa was studied. On average, 34% (20%-54%) of the animals rebled with no significant difference between the treatment groups. CONCLUSIONS Gelatin-containing products provided a fast hemostasis in this experimental model. One third of the animals rebled, regardless of whether thrombin or rFVIIa was added. Further studies are demanded to confirm these results clinically.

Early and intermediate outcome of emergency endovascular aneurysm repair of ruptured infrarenal aortic aneurysm: a single-centre experience of 90 consecutive patients.

OBJECTIVE To evaluate the early and intermediate outcome of a consecutive series of emergency endovascular aneurysm repairs (eEVAR) of computed tomography (CT)-verified infrarenal ruptured abdominal aortic aneurysm (rAAA) at a single tertiary referral centre. METHODS Prospectively collected data of patients operated between April 2000 and October 2007 were retrospectively reviewed and all their pre-, intra- and postoperative imaging were re-evaluated. Patient and procedural data were analysed using a Cox multiregression model. RESULTS Ninety patients (86% men, aged 76 (+/-7) years), were identified and included in the analysis. Symptom duration was <3h in 22% of patients, 3-24h in 39% and >24h in 39%. Mean aneurysmal diameter was 73 (+/-14)mm. All patients were treated with the COOK Zenith stent-graft (56% bi-iliac and 44% uni-iliac). Sixty-one percent were haemodynamically unstable on presentation, and 26% required an intra-operative aortic occlusion balloon to maintain haemodynamic stability. The 30-day and 1-year mortality rates were 27% and 37%, respectively. One-year aneurysm-related mortality was 33%. Twenty-eight percent of patients required re-interventions during the follow-up. The use of an aortic occlusion balloon and the presence of cerebrovascular disease or obstructive lung disorder correlated significantly with 30-day mortality in the multivariate analysis. CONCLUSION EVAR is a valid treatment option for rAAA when used as a first-line method for all patients.

In vitro and in vivo evaluation of chemically modified degradable starch microspheres for topical haemostasis

Degradable starch microspheres (DSMs) are starch chains cross-linked with epichlorhydrin, forming glycerol-ether links. DSMs have been used for many years for temporary vascular occlusion and drug delivery in treatment of malignancies. They are also approved and used for topical haemostasis by absorbing excess fluid from the blood and concentrating endogenous coagulation factors, thereby facilitating haemostasis. This mechanism of action is not sufficient for larger bleedings in current chemical formulations of DSMs, and modification of DSMs to trigger activation of platelets or coagulation would be required for use in such applications. Chemical modifications of DSMs with N-octenyl succinic anhydride, chloroacetic acid, acetic anhydride, diethylaminoethyl chloride and ellagic acid were performed and evaluated in vitro with thrombin generation and platelet adhesion tests, and in vivo using an experimental renal bleeding model in rat. DSMs modified to activate platelets in vitro were superior in haemostatic capacity in vivo. Further studies with non-toxic substances are warranted to confirm these results and develop the DSM as a more effective topical haemostatic agent.

Short- and midterm results of the fascia suture technique for closure of femoral artery access sites after endovascular aneurysm repair.

Purpose To evaluate the midterm outcomes and potential risk factors associated with the fascia suture technique (FST) for closure of femoral artery access sites after percutaneous endovascular aneurysm repair (EVAR). Methods Between April 2007 and April 2008, 100 consecutive EVAR cases were evaluated retrospectively. A third of the procedures were emergent (16 ruptured aneurysms). Of the 187 femoral access sites, 160 (85.5%) were closed by the FST as a first choice. Pre- and postoperative chart and imaging data were collected from computerized medical records for analysis of demographics and the rate of complications (bleeding, infection, thrombosis, pseudoaneurysms, and stenosis). Preoperative risk factors for FST failure were analyzed with regard to obesity (based on the subcutaneous fat layer), plaque at the femoral access site, and stenosis based on the pre- and 1-year postoperative computed tomography scans. Results Of the 160 FST closures, 146 (91.3%) were technically successful. The 14 (8.8%) technical failures were converted to open cutdown intraoperatively because of bleeding (11, 6.8%), inadequate limb perfusion (2, 1.2%), and a broken guidewire (1, 0.6%). Two (1.2%) pseudoaneurysms required surgical repair after 2 weeks. Data from the 1-year follow-up showed no signs of increased stenosis, thrombosis, or formation of plaque. Nine small (<1 cm3) pseudoaneurysms were detected and managed conservatively. No preoperative risk factors were associated with FST failure. Conclusion The fascia suture technique seems to be safe, effective, and simple to use for closing percutaneous access sites after EVAR. Complications are rare, and the outcome is not affected by obesity, femoral calcification, or femoral artery stenosis.

Staged proximal deployment of the Zenith TX2 thoracic stent-graft: a novel technique to improve conformance to the aortic arch.

Purpose: To present a modification of the Zenith TX2 thoracic stent-graft that allows staged proximal deployment to improve apposition to the aortic wall. Technique: Three standard Zenith TX2 thoracic stent-grafts and 3 modified versions were deployed in a glass model of the aortic arch. Deployment sequences were analyzed. In a patient with a 6-cm thoracic aortic aneurysm after a type B dissection, the modified Zenith TX2 thoracic stent-graft was deployed successfully and without complications; the proximal part of the stent-graft protruded less into the arch, significantly improving wall apposition. Conclusion: Staged proximal deployment with a modified Zenith TX2 thoracic stent-graft can improve orientation and wall apposition of the first Z stent. A better proximal apposition may prevent early and late stent-graft complications.

80-kVp CT angiography for endovascular aneurysm repair follow-up with halved contrast medium dose and preserved diagnostic quality.

Background Follow-up of endovascular aneurysm repair (EVAR) with life-long computed tomography angiography (CTA) surveillance exposes patients with impaired renal function to repeated risks of contrast medium-induced nephropathy (CIN). Purpose To retrospectively compare vascular attenuation, image noise, contrast-to-noise ratio (CNR), subjective image quality and effective radiation dose (mSv) for CTA with a 16-multirow detector CT (MDCT) equipment at 80 kVp after EVAR using a contrast medium (CM) dose that is half of that used at 120 kVp. Material and Methods Forty patients with estimated glomerular filtration rate (eGFR) <45 mL/min underwent 80-kVp CTA with 160 mg I/kg, and 40 patients with eGFR ≥45 mL/min 120-kVp CTA with 320 mg I/kg (maximum dose weight, 80 kg). Arterial phase analysis included vascular attenuation, image noise and CNR, and calculated effective dose. Subjective image quality was assessed on a 4-point scale by two blinded readers at three different levels as well as overall. Results Median values in the 80/120 kVp cohorts were: age, 74–75 years; body weight, 77/80 kg; BMI 24/27 kg/m2; CM dose, 13/25 gram-iodine; gram-iodine/GFR ratio, 0.35/0.38; mean aortic attenuation, 313/326 HU; image noise, 26/32 HU; CNR 10–11; subjective image quality score, 3.0–3.5 (Reader 1) and 3.0–3.3 (Reader 2); number of non-diagnostic examinations, 0/1; and effective dose, 4.5/5.1 mSv. There was no statistically significant difference in aortic CNR and effective dose between the 80 and 120 kVp cohorts. Conclusion 80 kVp 16-MDCT with halved CM dose tailored to body weight for CTA follow-up of EVAR may provide satisfactory diagnostic results compared to common standards and be beneficial for patients at risk of CIN, though the present CT equipment may limit the use of the method to patients below 90 kg or with a BMI below 35 kg/m2.

Suitability of the Zenith p-Branch Standard Fenestrated Endovascular Graft for Treatment of Ruptured Abdominal Aortic Aneurysms.

Purpose: To evaluate the anatomic suitability of the Zenith pivot branch (p-branch) fenestrated device in ruptured abdominal aortic aneurysms (rAAA). Methods: Contrast-enhanced computed tomography (CT) images of 206 patients (mean age 75±8 years; 175 men) with rAAA were evaluated in a dedicated 3-dimensional vascular workstation. All aneurysms found unsuitable for standard infrarenal repair were evaluated for Zenith p-branch suitability according to the Investigational Device Exemption protocol for both device configurations (A, pivot fenestrations at the same level; B, right renal fenestration located more cranially). Results: The suitability of the p-branch (A or B configuration) for short neck aneurysms (<15 mm; n=89) was 49%; of the 26 different combinations of exclusion criteria, a mismatch between a renal artery takeoff and the positioning of the corresponding fenestration was the most common. For juxta- and pararenal aneurysms (neck length <10 mm; n=66), suitability was 48%. Suitability assessed by target vessel positioning only (excluding all other limiting factors) was 58% for short neck aneurysms (n=52) and 55% for juxta- and pararenal aneurysms (n=36). Conclusion: Approximately half of patients with short neck rAAAs would be suitable for the Zenith p-branch fenestrated device according to the instructions for use. In almost 60%, the pivot fenestrations can accommodate the corresponding target vessels. More studies are needed to confirm these findings.