Dieter Raithel

Postoperative Color Flow Duplex Scanning in Aortic Endografting

PURPOSE To report the feasibility and sensitivity of duplex sonography compared to computed tomography (CT) for aortic endograft follow-up surveillance. METHODS In a 26-month period, 113 aortic aneurysm patients received 79 tube and 34 bifurcated stent-grafts. Follow-up used contrast-enhanced CT scanning and duplex sonography with an intravenous ultrasound contrast agent (Levovist). RESULTS Eleven patients (9.7%) were converted to open repair; 1 died from hemorrhagic shock secondary to retroperitoneal hematoma. The mean follow-up time was 7.2 months (range 1 to 24), during which 5 patients died of unrelated causes. Sixteen primary (within 30 days) and 5 secondary endoleaks were detected by duplex after tube graft implantation. Among 5 endoleaks due to retrograde side-branch perfusion, 3 were detected only with contrast-enhanced duplex scanning. Iliac artery occlusion was also documented using duplex; however, 2 stent fractures could not be seen with ultrasound. Ten primary endoleaks were detected in bifurcated stent-graft patients. One endoleak originating from the distal iliac limb anchoring site was missed by duplex owing to bowel gas. Graft limb thrombosis was clearly identified by lack of a flow signal on duplex. CONCLUSIONS Duplex sonography could be a valuable, reliable, and economical surveillance tool for endovascular aortic reconstructions. The adjunctive use of an intravenous ultrasound contrast agent increased the sensitivity for detecting endoleak to a level comparable to contrast-enhanced CT scanning. However, stent fractures may not be seen on ultrasound, and bowel gas can interfere with obtaining an adequate image.

Surgical Conversion after Endovascular Grafting for Abdominal Aortic Aneurysms

PURPOSE To analyze the indications, results, and technical problems associated with conversion after endoluminal repair of abdominal aortic aneurysms (AAA) based on a 6-year experience in endovascular grafting. METHODS From August 1994 to May 2000, 520 patients with AAA were deemed candidates for endovascular therapy based on data from contrast-enhanced computed tomography and aortography. Any conversions were performed using an open operation modified according to the indication for conversion, elapsed time from the endoluminal repair, and type of endograft (tube, bifurcated, infra-/suprarenal fixation). RESULTS Conversion to open repair was required in 37 (7.1%) cases: 23 tube grafts and 14 bifurcated devices. Seventeen (3.2%) conversions occurred at the original operation and 20 (3.8%) were performed secondarily. Indications for primary conversion were mainly device defects (n = 5) or access problems (n = 5), while secondary conversion was primarily owing to type I endoleak (n = 16). The conversion rate was significantly higher in modular devices (5.9%) than unibody designs (1.4%) (p = 0.003). The rate of primary conversions diminished from 10.9% in 1994-1995 to 2.4% between 1996 and 2000, as did the overall mortality rate, from 8.3% in the first time period to 0% in the second for elective conversions, but emergency operations had 40% mortality. CONCLUSIONS Most AAAs require bifurcated devices for complete exclusion, and older model modular grafts have higher conversion rates. Primary conversion decreases as more experience in endoluminal grafting is acquired. Emergency open repair results in a high mortality rate.

Incidence of Renal Infarctions after Endovascular AAA Repair: Relationship to Infrarenal versus Suprarenal Fixation

Purpose: To analyze the incidence and etiology of renal infarctions following endovascular abdominal aortic aneurysm (AAA) repair detected on computed tomography (CT) and determine any association with infrarenal versus suprarenal fixation. Methods: Between August 1994 and October 2001, 663 patients (604 men; mean age 68.5 years, range 40–98) underwent endovascular AAA repair with predominately bifurcated (505, 77%) stent-grafts. About a third (202, 30%) of the devices were deployed in a suprarenal position. Contrast-enhanced CT scans were performed on days 10, 90, and 365 after operation and then annually. Two radiologists blinded to procedural details compared the preoperative and postoperative scans to identify renal infarctions from inadvertent renal artery occlusion by the endograft. Only patients with inadvertent infarctions were analyzed relative to endograft fixation position and stent-graft type. Results: Mean follow-up was 37 months (range 0.1–75). Overall renal infarction rate was 11.9% (n=79); 23 (3.4%) patients suffered from limited, segmental infarction due to intentional covering of preoperatively diagnosed accessory renal arteries. Unintentional renal ischemia was identified in 56 (8.5%) patients. In this subgroup, 39 (19%) were observed in the 202 patients with suprarenal fixation versus 17 (3.7%) in the 461 stent-grafts positioned infrarenally (RR 3.35, 95% CI 2.20 to 5.04, p < 0.00001). There was a significant correlation between the incidence of infarction and the device type (14.3% for modular grafts versus 5.6% for unibody designs, p = 0.0002). Seventeen (2.6%) patients suffered from unilateral kidney loss, with dialysis required in 2 cases. Creatinine and urea showed no significant postoperative elevation in the overall patient population, but both levels were significantly (p < 0.02) elevated in patients with complete unilateral renal infarcts. Conclusions: Transrenal fixation of aortic endografts had a 3-fold higher risk for renal infarction in this large patient population. There is no significant difference for specific endografts, but modular designs were associated with a higher rate of renal infarction. The need to occlude preoperatively diagnosed accessory renal arteries with an endograft should be considered a contraindication for current available devices.

Aortic aneurysm size and graft behavior after endovascular stent-grafting: clinical experiences and observations over 3 years.

Purpose: To assess the long-term safety and efficacy of aortic endografts in terms of clinical outcome, continuing aneurysm exclusion, and changes of aneurysm size and graft configuration. Methods: Between August 1994 and July 1997, 190 patients (176 men; mean age 68.7 years, range 40–87) with aortic and aortoiliac aneurysms were treated with endovascular stent-grafts (Stentor, Vanguard, and EGS) in a tertiary care municipal hospital setting. Follow-up involved clinic visits every 3 to 6 months with contrast-enhanced computed tomography (CT), color duplex, and plain abdominal radiographs at regular intervals; angiography was used selectively. All data were collected prospectively and entered into a computerized database. Results: Implantation was possible in 188 (98.9%) patients. Early conversion to open surgical repair was required in 14 (7.4%) patients. Primary endoleaks were detected in 32 (16.8%) patients. Perioperative mortality was 0.53% (1/190). During follow-up, 17 (8.9%) additional patients were converted to open repair over a mean 20.9 months. Thirty-seven secondary procedures to treat endoleaks and pelvic outflow occlusions were performed in 30 (15.8%) patients. Changes in stent configuration suggestive of endograft disintegration were observed in 31 (29.8%) of 104 abdominal radiographs. Intraluminal layering of thrombus was seen on contrast-enhanced CT images in 20 patients. A significant trend (χ24 = 12.34, p < 0.025) toward aneurysm enlargement was seen in patients with persistent endoleaks at a mean 18-month follow-up. Conclusions: Although endoleaks after aortic stent-graft placement tend to cause ongoing aneurysm growth, we have also observed aneurysm shrinkage despite ongoing endoleak. The presence or absence of an endoleak in itself may be a poor predictor of successful stent-graft therapy. Lifelong surveillance is needed to assure successful aneurysm exclusion and stability or shrinkage of the aneurysm sac. Technical improvements in stent materials and design are necessary to guarantee long-term stability and safety of the device.

Experience With the Endologix Powerlink Endograft in Endovascular Repair of Abdominal Aortic Aneurysms With Short and Angulated Necks

Endovascular aortic aneurysm repair (EVAR) for anatomically suitable abdominal aortic aneurysms (AAAs) has gained wide acceptance in the past decade, and EVAR for anatomically challenging or unsuitable AAAs such as short and angulated neck AAAs has become a hotly debated subject. The objective of this study is to summarize the unique experience of EVAR for short / angulated neck AAAs with Powerlink unibody bifurcated stent-graft. Data were retrospectively analyzed from 519 patients in our single unit from February 1999 to December 2007 who underwent EVAR using the Powerlink endograft, and had short or angulated necks. Short neck was defined as < or = 15 mm for the infrarenal neck length, and it was divided into 2 groups: Group A (short neck), 54 cases with the length 11 to 15 mm; and Group B (very short neck), 26 cases with the length < or = 10 mm. Angulated neck of 37 cases which was defined as > or = 60 degrees angulation between the longitudinal axis of infrarenal aorta and the aneurysm. The unique strategy of treating short / angulated neck AAAs is to build up the endoluminal exclusion system from the native aortic bifurcation to the renal artery level with suprarenal fixation. The Powerlink unibody bifurcated stent graft was implanted anatomically fixed on the aortic bifurcation and a long suprarenal cuff was built up to the renal arteries. A Palmaz stent can be used for proximal fixation and sealing enhancement in the most challenging necks. The follow-up imaging was performed at 1 month, 6 months, and yearly thereafter. The technical success rate was 97.4% (114/117). Intraoperative complications included 3 conversions due to delivery access problems, 6 proximal type I endoleaks, and 5 type II endoleaks. The 30-day mortality was 1.7% (2/117). The 2.6-year follow-up showed 4 (3.4%) proximal type I endoleaks, which were revised with proximal cuff and/or Palmaz stent. Limb occlusion occurred in 2 cases, and the total re-intervention rate was 5.3%. Three (2.6%) type II endoleaks were left in observation. There were 3 (2.6%) partial renal infarctions, no stent-graft distal migration, and no post-EVAR ruptures. Our experience demonstrates that building up the endoluminal exclusion system from the abdominal aortic bifurcation to the renal artery level using the Powerlink fully supported unibody bifurcated stent-graft with a long suprarenal cuff, and a Palmaz stent when needed, proved safe and effective in treating AAAs with short and angulated necks.

Recurrent carotid disease: optimum technique for redo surgery.

Carotid restenosis has been a well-recognized, though not well-understood, long-term complication of carotid endarterectomy. Various factors contribute to recurrent stenosis, but the chief cause is technical faults during the primary procedure. Redo endarterectomy or graft reconstruction are the traditional and most effective procedures for treating symptomatic or high-grade (> 80%) asymptomatic restenotic lesions. To reduce the potential for carotid restenosis, eversion endarterectomy is recommended as the technique of choice for de novo carotid disease treatment. Angioscopy is useful in detecting correctable technical errors that could predispose to restenosis.

Preliminary embolization of the hypogastric artery to expand the applicability of endovascular aneurysm repair.

Purpose: To evaluate the efficacy and safety of preliminary hypogastric artery (HA) embolization prior to endovascular aneurysm repair (EVAR). Methods: A retrospective review was conducted of all 101 consecutive patients (91 men; mean age 73.4±8.7 years) who underwent preliminary embolization of 133 HAs ~4 to 6 weeks prior to EVAR from January 2005 to August 2009. Fourteen patients with 19 HAs were treated using coils, while 87 patients were treated with Amplatzer Vascular Plugs (AVP) in 114 HAs. All the patients were evaluated before discharge; at 1, 3, and 6 months; and annually thereafter to evaluate the clinical symptoms, potential endoleaks, and the aneurysm size. Results: In the coil group, complete occlusion was achieved in 16 (84.2%) of 19 procedures. There were no acute pelvic ischemic symptoms after HA embolization or EVAR. Five (35.7%) patients had buttock claudication and 2 (16.7%) of 12 men experienced new erectile dysfunction after embolization. At a mean 42.2-month follow-up (range 14–58), 3 (21.4%) patients had a type II leak via retrograde flow in the HA without aneurysm growth and were under observation. In the AVP group, all 114 HAs in 87 patients were successfully occluded; there was no device dislodgment or acute pelvic or limb ischemia observed. Buttock claudication and new sexual dysfunction developed in 12 (13.8%) patients and 4 (5.1%) of 79 men after the procedure, respectively. During a mean 26.4-month follow-up (range 4–54), 2 (2.3%) patients developed distal type I endoleaks after EVAR, but angiography confirmed that neither of the endoleaks was related to the vessel embolized with the AVP. Comparing the outcomes of the treatment groups, the AVP was placed with fewer intraoperative complications (p = 0.013) and more complete occlusion (p=0.01) than coil embolization. The rate of buttock claudication was lower in the AVP group (p=0.042). Conclusion: Hypogastric artery embolization prior to EVAR is safe and effective. In our experience, the AVP affords easier and more precise placement and provides more

Two-Year Single-Center Experience with Thoracic Endovascular Aortic Repair Using the EndoFit Thoracic Stent-Graft

Purpose: To analyze our single-center experience of thoracic endovascular aortic aneurysm repair (TEVAR) using the EndoFit Thoracic Aortic Endograft. Methods: A retrospective review was conducted of 87 consecutive patients (64 men; median age 67.8±8.7 years, range 24–88) undergoing TEVAR using the EndoFit thoracic stent-graft from December 2005 to December 2007. Slightly more than half (n=46) of the patients had thoracic aortic aneurysm, while 41 had thoracic aortic dissection. Seventeen cases were performed emergently. All patients had imaging follow-up before discharge; at 1, 3, and 6 months; and annually thereafter. Results: The technical success rate was 100%. Fifty-five (63.2%) patients had different debranching procedures to extend the proximal or distal landing zone. The in-hospital and 30-day mortality rate was 9.2% (8/87). Neurological complications occurred in 8 (9.3%) patients, including 5 strokes (2 fatal) and 3 cases of paraplegia. One intraoperative massive bleeding from an ascending aortic debranching anastomosis was rescued with the aid of a pump. Five patients had immediate proximal type I endoleak; 3 were remedied with a proximal cuff, 1 was rescued with tri-lobe balloon, and 1 was left untreated. One type II endoleak remains under observation. The average follow-up was 15.2 months (range 5–29), during which 10 (11.5%) patients died of causes unrelated to the aneurysm or stent-graft. All the extra-anatomical bypasses and stent-grafts were patent; no stent-graft kinking, collapse, or dislocation was detected. Two post-TEVAR proximal endoleaks were remedied with a proximal cuff after debranching. There was no post-TEVAR rupture or conversion to open surgery. Conclusion: Our 2-year single-center experience using the EndoFit system for TEVAR showed a high technical success rate and a low incidence of device- or aneurysm-related complications. The flexible, hydrophilic introducer was easy to insert and track through the vasculature. The debranching techniques to extend the landing zones not only broaden the applicability of TEVAR but also reduce post-TEVAR complications.

Aortocaval fistula after stent-graft repair

Purpose: To report an aortocaval fistula after stent-graft repair and the feasibility of interventional treatment. Case Report: A 78-year-old man with a 61-mm infrarenal aortic aneurysm (AA) was treated successfully with a Zenith bifurcated stent-graft. Three years later, the patient presented with deteriorating renal function and acute bronchial obstruction. Computed tomography showed an aortic diameter increased to 90 mm, dilatation of the inferior vena cava, and a distal type I endoleak. The patients condition quickly deteriorated, and emergent imaging found a fistula with brisk flow between the aneurysm sac and the left iliac vein within a distal type I endoleak. During emergency endovascular repair, iliac extensions were implanted in the right common iliac artery and left external iliac artery. The left hypogastric artery was coil embolized to exclude flow into the aneurysm sac. After positioning the extensions, cardiac function improved, and the fistula was no longer palpable. The cardiac indices and renal function normalized, and he was discharged 20 days after admission. Conclusion: Aortocaval fistulas are a rare complication of AA stent-graft repair and may be successfully treated by interventional means.

Die periphere septische Embolie als Primärsymptom eines infizierten aortobifemoralen Bypasses mit sekundärer aortoduodenaler Fistel

Zusammenfassung Wir berichten über einen 55-jährigen Patienten mit einer Arrosionsperforation eines aortobifemoralen Bypasses in das Duodenum. Retrospektiv betrachtet, stellten periphere septische Embo- lien in diesem Fall das Primärsymptom einer aortoenterischen Fistel dar. Die diagnostische Abklärung erfolgte zunächst wegen einer schmerzhaften Schwellung des linken Unterschenkels mit dem Verdacht einer tiefen Beinvenenthrombose. Die weiterführende Diagnostik ergab den überraschenden duodenoskopischen Befund eines eitrigen Prothesen- infekts und Duodenaldefekts. Die Therapie beinhaltete bei stabilem Patienten die präliminare Anlage eines aseptischen axillobifemoralen Bypasses mit anschließender Explantation der Y-Prothese und Verschluss des Duodenums mit Sicherung durch eine Omentumplastik. Die Nekrosen am Unterschenkel, die praktisch die ganze Zirkumferenz betrafen, wurden in einer 2. operativen Sitzung debridiert und zwei- zeitig plastisch-chirurgisch gedeckt. Zur Problematik sekundärer aortoenterischer Fisteln in Diagnostik und Therapie wird im Rahmen einer Literaturrecherche Stellung genommen.Abstract History, clinical signs, diagnosis, and treatment of a 55-year-old patient with aortoenteric fistula after aortobifemoral bypass repair are reported. The patient presented with painful swelling of the left lower leg and deep vein thrombosis was suspected. Duodenoscopy showed an aortoenteric fistula and the aortic prosthesis was visible. The bifurcated graft was removed, the duodenal defect was closed and covered by omentoplasty. Revascularization was performed by axillobifemoral bypass. Retrospectively, septic embolization was the primary symptom of an aortic graft infection. Pathogenesis, clinical presentation, and operative management of aortoenteric fistula after aortic aneurysm repair are discussed.