Siegfried Thurnher

Endoluminal Stent–Grafts for Infrarenal Abdominal Aortic Aneurysms

BACKGROUND The treatment of aortic aneurysms with endovascular stents or stent-graft prostheses is receiving increasing attention as an alternative to major abdominal surgery. To define the clinical value of this technique, we prospectively studied the use of stent-graft endoprostheses made of nitinol and covered with polyester fabric for the treatment of infrarenal abdominal aortic aneurysms. METHODS We treated a total of 154 patients at three academic hospitals. Twenty-one patients with aortic aneurysms not involving the aortic bifurcation received straight stent-grafts, and 133 patients with aortic aneurysms involving the bifurcation and the common iliac arteries received bifurcated stent-grafts. After a unilateral surgical arteriotomy, the endoprostheses were advanced through the femoral arteries and placed under fluoroscopic guidance. Computed tomography and intraarterial angiography were performed during an average follow-up of 12.5 months. RESULTS The primary success rate, defined as complete exclusion of the abdominal aortic aneurysm from the circulation, was 86 percent in the group receiving straight grafts and 87 percent in the group receiving bifurcated grafts. In three patients the procedure had to be converted to an open surgical operation. Minor (n=13) or major (n=3) complications associated with the procedure (including 1 death) occurred in 10 percent of the patients. All patients had a postimplantation syndrome, with leukocytosis and elevated C-reactive protein levels. CONCLUSIONS Our results suggest that endovascular treatment of infrarenal abdominal aortic aneurysms is technically feasible and can effectively exclude abdominal aortic aneurysms from the circulation. With further refinement, endoluminal repair may emerge as an interventional strategy to treat infrarenal aortic aneurysms, especially in patients at high surgical risk.

PTA versus Palmaz Stent Placement in Femoropopliteal Artery Obstructions: A Multicenter Prospective Randomized Study

PURPOSE To evaluate if stent placement is superior to percutaneous transluminal angioplasty (PTA) in the treatment of chronic symptoms in short femoropopliteal arterial lesions. MATERIALS AND METHODS One hundred fifty-four limbs in 141 patients who ranged in age from 39 to 87 years (mean age, 67 years) were randomized to PTA (n = 77) versus PTA followed by implantation of Palmaz stents (n = 77). Inclusion criteria were patients with intermittent claudication (n = 108, Society of Vascular Surgery/International Society of Cardiovascular Surgery [SVS-ISCVS] categories 1-3) or chronic critical limb ischemia (n = 46 with either ischemic rest pain [category 4] or minor tissue loss [category 5]), short stenosis or occlusion (lesion length < or = 5 cm), and at least one patent run-off vessel at angiography. Follow-up included clinical assessment, measurement of ankle/ brachial index (ABI), color duplex ultrasound, and/or angiography at 6 or 12 months. Angiographic follow-up between 12 and 36 months was available in 46 limbs (29.9%). RESULTS In the PTA group, initial technical success was achieved in 65 of 77 limbs (84%) versus 76 of 77 (99%) limbs in the stent group (chi2 value = 0.009). Overall, major complications occurred in 3.9% (n = 6); n = 4 in the PTA group compared to n = 2 in the stent group. There was no difference between groups of treatment: hemodynamic/clinical success at 1 and 2 years in the PTA group was 72% and 65% versus 77% and 65% in the stent group (Gehan P value = .26). The cumulative 1- and 2-year angiographic primary patency rates were 63% and 53%, respectively, for both groups. The secondary 1- and 2-year angiographic patency rates were 86% and 74% in the PTA group versus 79% and 73% in the stent group (P = .5). CONCLUSION After stent placement, the primary success rate was significantly higher than after PTA. However, 1-year angiographic and clinical/hemodynamic success was not improved.

Endovascular stent graft repair for aneurysms on the descending thoracic aorta

BACKGROUND The traditional treatment of aneurysms of the descending thoracic aorta includes posterolateral thoracotomy and aortic replacement with a prosthetic graft. In this study, we report our experiences and results in endovascular stent graft placement as an alternative to surgical repair. METHODS Between January 1989 and July 1997, a total of 68 patients (24 women) underwent replacement of the thoracic aorta. Mean age at operation was 51 years. Fifty-eight patients underwent conventional surgical treatment. All of these patients were suitable candidates for endovascular stenting; however, no stent graft material was available at the time of operation. Ten patients (1 chronic dissection, 9 atherosclerotic aneurysm) received in the past 8 months the first commercially manufactured endovascular stent graft. The mean diameter of the aneurysms in this group was 7 cm (range, 6 to 8 cm). Two stent patients were operated on using only spinal cord analgesia. All stent grafts were custom designed for each of the 10 patients. RESULTS The 30-day mortality in the conventional group was 31% versus 10% in the stent group. Mean length of intervention was 320 minutes in the conventional group versus 150 minutes in the endovascular group. Spinal cord injury occurred in 5 patients (12%) in the surgical group, whereas none of the stented patients developed any neurologic sequelae. Mean intensive care unit stay was 13 days, followed by a mean of 10 days on a ward in the first group compared to 4 days in the intensive care unit and 6 days on the ward in the stent group. One stent was required in 2 patients, two stents were required in 3 patients, and four stents were deployed in 5 patients of our series. Five patients required transposition of the left subclavian artery to achieve a sufficient neck for the proximal placement of the stent. There was complete thrombosis of the thoracic aortic aneurysm surrounding the stent graft in 8 patients (80%). Two patients required restenting as a result of leakage (20%). Stent graft placing was performed through the femoral artery in 8 patients, whereas access was only achieved through the abdominal aorta in 2 patients. CONCLUSIONS These preliminary results demonstrate that endovascular stent graft replacement might be a promising, cheaper, and safe alternative method in selected patients with descending thoracic aneurysms.

Thoracic aortic aneurysms: treatment with endovascular self-expandable stent grafts ☆

BACKGROUND This study was performed to evaluate the safety and feasibility of endovascular stent graft placement in the treatment of descending thoracic aortic aneurysms. METHODS Between November 1996 and February 1999, endovascular stent graft repair was used in 21 patients. There were 5 women and 16 men with a mean age of 67 years (range, 41 to 87 years). An atherosclerotic aneurysm with a diameter of more than 6 cm was the indication for intervention in 19 patients (90.5%). In 2 patients (9.5%), a localized aortic dissection with a diameter of more than 6 cm was treated. In 71.4% (15 of 21) of patients, multiple stents were necessary for aneurysm exclusion. To allow safe deployment of the stent graft, preliminary subclavian-carotid artery transposition was performed in 9 patients (42.9%). Vascular access was achieved through a small incision in the abdominal aorta (n = 6), an iliac artery (n = 8), or a femoral artery (n = 7). Talent and Prograft stent grafts were used. RESULTS Successful deployment of the endovascular stent grafts was achieved in all patients. Two patients died postoperatively (mortality rate, 9.5%), 1 of aneurysmal rupture and the other of impaired perfusion of the celiac axis. Repeat stenting was done in 3 patients because of intraoperative leakage. CONCLUSIONS Endovascular stent graft repair is a promising and less invasive alternative to exclude the aneurysm from blood flow. This technique allows treatment of patients who are unsuitable for conventional surgical procedures. An exact definition of inclusion criteria and technical development of stent grafts should contribute to further improvements in clinical results.

MR angiography vs CT angiography in the follow-up of nitinol stent grafts in endoluminally treated aortic aneurysms

Abstract. Our objective was to evaluate the accuracy of contrast-enhanced 3D MR angiography (MRA) in the follow-up of patients with endoluminally treated aortic aneurysms and correlate these findings with uni- or biphasic CT angiography (CTA). Forty MR angiograms in 32 patients with implanted aortic nitinol stent grafts were compared to CTA. Twenty-two MR examinations were correlated with arterial-phase CTA (uniphasic), and 18 MR examinations were correlated with biphasic CTA. Uniphasic CTA demonstrated three type-1/type-3 endoleaks and four reperfusion (type-2) endoleaks. In addition, MRA depicted two type-2 reperfusion endoleaks that were missed by CTA. Using biphasic CTA, two type-1/type-3 endoleaks and three reperfusion (type-2) endoleaks were detected; of those, delayed scanning detected three reperfusion (type-2) endoleaks missed during arterial-phase CTA. In addition to the findings by CTA, MRA depicted another type-2 reperfusion endoleak. Magnetic resonance angiography is at least as sensitive as uni- or biphasic CTA for detecting endoleaks and may consequently offer advantages in patients with contraindications to iodinated contrast agents.

Embolization of Iatrogenic Vascular Injuries of Renal Transplants: Immediate and Follow-Up Results

AbstractPurpose: To evaluate the outcome in seven patients in whom iatrogenic vascular complications were treated with catheter embolization. Methods: Angiography showed an arteriovenous fistula in six of the seven patients, a pseudoaneurysm in three patients, and an arteriocaliceal fistula in three patients. Embolization was performed with GAW coils or microcoils in all cases. In three patients enbucrilate, polyvinyl alcohol, or absorbable gelatin powder was administered as an adjunct to the coils. Results: Angiographic success with total occlusion of the vascular injury was achieved in five of the seven patients and clinical success was achieved in four of seven cases. In two cases, nephrectomy after embolization was necessary because of renal artery occlusion or acute hemorrhage at the renal artery anastomosis, respectively. Infarction of 30%–50% of the renal parenchyma was seen in two cases. Conclusion: Angiographically successful embolization is not necessarily associated with clinical success. The complication rate is high.

Endovascular Stent Grafting Versus Open Surgical Operation in Patients With Infrarenal Aortic Aneurysms

Background— Although transfemoral endovascular aneurysm management (TEAM) of infrarenal abdominal aortic aneurysms (AAA) is widely performed, open graft replacement is still considered the standard of care. The aim of this study was to investigate whether clear indications for TEAM can be established in patients with significant comorbidities without investigating differences in relative procedure efficacy or durability. Methods and Results— A propensity score–based analysis of 454 consecutive patients treated electively for AAA from January 1995 through December 2000 was performed. Of those 454 patients, 248 received open surgery and 206 received TEAM. In-hospital mortality rates (MRs) were compared. After adjusting for propensity scores, a Cox proportional hazard model (COX) was employed to test the influence of the respective treatment on postoperative 900-day survival estimates (SEs). Several potential preoperative risk factors were used as covariates. The MR of all patients was 3.7%. Explorative anal...

Imaging of aortic stent-grafts and endoleaks

Although the technical success of stent-graft implantation is established and relatively safe, data on the long-term safety and efficacy of endovascular repair are just emerging. Because several late complications of aortic stent-graft placement have been observed, life-long follow-up remains essential. Imaging methods form an integral part of every stage of endovascular aortic aneurysm repair. The current imaging strategy should include initial plain films, CT angiography, and color-coded Duplex sonography. Plain films are an excellent means to detect migration, angulation, kinking, and structural changes of the stent mesh, including material fatigue, at follow-up. Helical CT angiography is considered a potentially revolutionary method for the noninvasive complete postprocedural assessment of aortic sten-grafting. Current data justify the use of biphasic C angiography as the postprocedural imaging technique of choice in most patients [118]. Ultrasound offers the advantages of low cost and lack of radiation exposure. High-quality ultrasound reliably excludes endoleaks in patients after stent-grafting of AAAs. There is a substantial variability, however, in measuring the diameter of aneurysm sacs; thus, confirmation using an alternative study is prudent in cases that demonstrate a significant change in size during follow-up. MR angiography serves as an attractive alternative to CT angiography in patients with impaired renal function or known allergic reaction to iodinated contrast media. With current techniques, the visualization of aortic stent-grafts (with the exception of stainless-steel-based devices) is sufficient with MR angiography. There is evidence that MR imaging is superior to CT angiography in detecting small type 2 endoleaks or for excluding retrograde perfusion in patients with suspected endotension. The role of diagnostic catheter angiography is limited to assessment of vascular pathways in equivocal cases or for suspected endotension. Currently, a consensus view about postprocedural management after aortic stent-graft implantation is lacking. The authors propose performing a baseline CT angiography at discharge and a biphasic CT angiography and Duplex ultrasound scan at three months. In patients with no evidence of an endoleak, CT angiography, plain film and Duplex sonography (abdomen) should be repeated every year after endovascular repair. If an endoleak is present at follow-up, immediate appropriate treatment should be initiated.

Covered self-expanding transhepatic biliary stents: Clinical pilot study

PurposeWe report our preliminary results with a new type of self-expanding covered stent for treatment of malignant biliary obstruction.MethodsWallstents, fully covered with high elasticity polyurethane, with an unconstrained diameter of 10 mm and a total length of 69 mm, were placed transhepatically under fluoroscopic guidance in five patients. The length of the biliary obstruction varied between 30–50 mm. At 1 and 3 months (82–98 days) clinical assessment, serum bilirubin measurement, and ultrasound examination of the biliary tree were performed.ResultsInitial uncomplicated deployment of the stents and internal drainage was possible in all patients. Distal stent migration resulted in early biliary reobstruction in one patient. At 3-month follow-up, partial reobstruction, most probably due to sludge formation, was found in another patient.ConclusionOur initial results indicate that the covered, self-expanding Wallstent endoprosthesis can be reliably and safely deployed transhepatically for malignant biliary obstruction.

Endovascular AAA treatment: Expensive prestige or economic alternative?

OBJECTIVES To compare the costs of endovascular aneurysm treatment versus open surgery during the perioperative period. METHODS Retrospective analysis of a consecutive series of 44 patients undergoing infrarenal abdominal aneurysm repair from February 1995 to March 1996 at a university teaching hospital. RESULTS No endovascular procedure was converted to open repair. Operative time was shorter for endovascular treatment (207.6 min vs. 229.1 min, n.s.), as well as postoperative intensive care unit stay (ICU, 22.7 h vs. 55.0 h, p = 0.017) and the postoperative recovery period (5.6 days vs. 13.3 days, p < 0.001). Open surgery generated significantly more costs (25,374.07 ECU vs. 22,268.78 ECU, p < 0.001), despite evaluation and a more expensive endovascular procedure (10,699.48 ECU vs. 4032.01 ECU, p < 0.001). During the study, costs for open surgery exceeded the cost for endovascular treatment by 13.95%. CONCLUSIONS Endovascular aneurysm treatment is cost effective and less expensive than open surgery. The main reason for cost saving is faster patient recovery after surgery, associated with a shorter LOS in the patients treated with endovascular procedure.