Thomas Pfammatter

Endoleaks after endovascular abdominal aortic aneurysm repair: detection with dual-energy dual-source CT.

PURPOSE To assess the diagnostic performance of dual-energy dual-source computed tomography (CT) in the detection of endoleaks after endovascular abdominal aortic aneurysm (AAA) repair. MATERIALS AND METHODS This study was local ethics board approved, and written informed consent was obtained from all patients. One hundred eighteen patients (21 women, 97 men; mean age, 74 years +/- 8 [standard deviation]) underwent follow-up dual-energy dual-source CT during the nonenhanced, arterial, and delayed phases after AAA repair. Delayed phase CT images were acquired in the dual-energy mode for reconstruction of virtual nonenhanced images. Two blinded and independent readers evaluated the data for the presence or absence of endoleaks during three reading sessions: Standard nonenhanced, arterial phase, and delayed phase images were read during session A; virtual nonenhanced, arterial phase, and delayed phase images, during session B; and virtual nonenhanced and delayed phase images, during session C. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated, with the session A image data set as the reference standard. Radiation dose parameters were estimated. RESULTS Reading session A revealed that 52 (44%) of 118 patients had endoleaks. Overall sensitivity, specificity, NPV, and PPV for CT endoleak detection during sessions B and C were identical: 100%, 97%, 100%, and 96%, respectively. The accuracy of the session B and session C readings was not significantly different from that of the session A reading (P = .50). The effective radiation dose in the image acquisition protocol involving one dual-energy scan was significantly (P < .001) lower than the effective doses in the protocols involving standard triple-phase scanning (mean difference, 61%) and standard nonenhanced and delayed phase scanning (mean difference, 41%). CONCLUSION Compared with standard protocols, one dual-energy dual-source CT scan performed during the delayed phase with reconstruction of virtual nonenhanced images enables detection of endoleaks after endovascular AAA repair with high accuracy and a considerably lower radiation dose.

Transarterial chemoembolization as a bridge to liver transplantation for hepatocellular carcinoma: an evidence-based analysis.

The aim of this review was to assess the impact of transarterial chemoembolization (TACE) as a neoadjuvant therapy prior to orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC). An electronic search on the Medline database (1990–2005) was used to identify relevant articles. The studies were reviewed and ranked according to their quality of evidence using the grading system proposed by the Oxford Centre for Evidence‐based Medicine. As a bridge to OLT, pretransplant TACE does not improve long‐term survival (grade C). There is currently no convincing evidence that TACE allows to expand the current selection criteria for OLT, nor that TACE decreases dropout rates on the waiting list (grade C). However, TACE does not increase the risk for postoperative complications (grade C). There is insufficient evidence that TACE offers any benefit when used prior to OLT, neither for early nor for advanced HCC. Well‐designed randomized controlled trials are needed to define the role of TACE in OLT patients.

Acute mesenteric ischemia caused by spontaneous isolated dissection of the superior mesenteric artery: treatment by percutaneous stent placement

Abstract. Spontaneous and isolated dissection of the superior mesenteric artery is a rare and often fatal event which has been successfully treated by surgery in several reported cases. We present a patient with acute mesenteric ischemia due to superior mesenteric artery dissection who was successfully treated by percutaneous endovascular placement of a Wallstent.

Acute traumatic aortic rupture: early stent-graft repair

OBJECTIVE Prospective evaluation of early stent-graft repair of acute traumatic aortic rupture. METHODS Twelve patients with acute traumatic aortic rupture of the descending aorta, out of a series of 337 endovascular aortic procedures, were treated by implantation of self-expanding stent-grafts. The procedures were performed within a mean post-injury time-period of 5+/-7 days (median: 1 day). The feasibility of stent-grafting was assessed by CT scanning and echography. Implantation was performed under local (n=6), or general anesthesia (n=6) if patients were already intubated (n=5) or required a common iliac artery access (n=1). RESULTS The immediate technical success rate was 100%. There were no post-procedure complications in all but one patient, who died 12 h postoperatively (8% mortality). Complete sealing of the aortic rupture in the remaining 11 patients was confirmed by postoperative CT scans. There were no intervention-related morbidity or mortality during the mean follow-up of 17 months. One patient with peri-graft leakage was successfully repaired with an additional stent-graft 12 months postoperatively. CONCLUSION Non-delayed or early stent-grafting in acute traumatic rupture of the descending aorta is feasible. This technique seems to be a valuable option, in particular when associated lesions may interfere with the surgical outcome. Immediate post-procedural CT scanning and/or echography should be performed, in order to rule out residual leakage.

10 years of emergency endovascular aneurysm repair for ruptured abdominal aortoiliac aneurysms: lessons learned.

Objective:To evaluate a single centers 10-year experience with emergency endovascular aneurysm repair (eEVAR) in 102 patients with ruptured abdominal aortoiliac aneurysms (RAAA). Methods:Data from 102 patients (mean age, 73 ± 9 years) with RAAA treated by eEVAR from January 1998 to April 2008 were retrospectively reviewed. From January 2000, all patients were treated according to an intention-to-treat protocol. The only exclusion criterion was unsuitable anatomy. 31/102 patients had moderate shock and 14/102 patients had severe shock with a systolic blood pressure <70 mm Hg or <50 mm Hg, respectively. 71/102 procedures were carried out under local anesthesia. Endograft types used were mainly bifurcated (92/102). Open abdomen treatment (OAT) because of abdominal compartment syndrome (ACS) was used when signs of organ failure occurred and/or bladder pressure rose >20 mm Hg. Results:The 30-day mortality for eEVAR was 13% (13/102). Technical success (defined as successful deployment of the endograft, absence of extravasation in the postprocedural contrast enhanced CT scan and hemodynamic stabilization) was 99% (101/102). Nineteen unstable patients (19%) required transfemoral supraceliac aortic balloon occlusion. ACS was detected and treated by OAT in 20 patients (20%). 16 type I, 26 type II and 1 type III endoleaks were detected on postoperative CT examination. Two patients had a combined type I and II endoleak. 11 patients were retreated for immediate correction of 10 type I and 2 type II endoleaks. 6 type I and 1 type III low-flow endoleaks were observed and resolved spontaneously within 30 days. Major 30-day morbidity was 35%. Conclusion:In this 102 patient contemporary series of eEVAR for RAAA, endografting proved to be safe with a 30-day mortality of 13%. Key components of this favorable outcome result were adequate preoperative diagnostic imaging, hypotensive hemostasis, selective transfemoral supraceliac aortic balloon occlusion, predominantly local anesthesia, detection and treatment of ACS, and attention to logistics. Widespread adoption of these treatment components is recommended.

Magnetic Resonance Angiography Versus Duplex Sonography for Diagnosing Renovascular Disease

Noninvasive testing for renovascular disease is required to identify patients who may benefit from revascularization procedures without exposing an unnecessary amount of patients to the risks of catheter angiography. All available methods of diagnosing renal artery stenosis have significant limitations. We compared a new technique, contrast-enhanced magnetic resonance angiography, with an established technique, duplex ultrasonography, for the detection of renal artery stenosis using catheter angiography as the standard of reference. Eighty-nine patients with clinically suspected renovascular disease underwent duplex renal scanning and contrast-enhanced magnetic resonance angiography. Sixty of these also underwent catheter angiography. All studies were interpreted for the presence of renal artery stenosis blinded to the results of the other imaging modalities. For detection of hemodynamically significant (>/=60% diameter reduction) main renal artery stenosis, sensitivity and specificity were 90% and 86%, respectively, for magnetic resonance angiography and 81% and 87% for duplex sonography. Most false readings involved differential grading of stenoses detected with all 3 techniques. When patients with fibromuscular dysplasia were excluded from the analysis, the sensitivity of magnetic resonance angiography increased to 97%, with a negative predictive value of 98%. Magnetic resonance angiography detected 96% and duplex 5% of accessory renal arteries seen at catheter angiography. Contrast-enhanced magnetic resonance angiography is a useful technique for diagnosing atherosclerotic renovascular disease. It overcomes the major limitations of duplex renal scanning. However, duplex has the advantage of providing hemodynamic information and appears better suited for the assessment of patients with suspected fibromuscular dysplasia.

MR-Guided Percutaneous Angioplasty: Assessment of Tracking Safety, Catheter Handling and Functionality

AbstractPurpose: Magnetic resonance (MR)-guided percutaneous vascular interventions have evolved to a practical possibility with the advent of open-configuration MR systems and real-time tracking techniques. The purpose of this study was to assess an MR-tracking percutaneous transluminal angioplasty (PTA) catheter with regard to its safety profile and functionality. Methods: Real-time, biplanar tracking of the PTA catheter was made possible by incorporating a small radiofrequency (RF) coil in the catheter tip and connecting it to a coaxial cable embedded in the catheter wall. To evaluate potentially hazardous thermal effects due to the incorporation of the coil, temperature measurements were performed within and around the coil under various canning and tracking conditions at 1.5 Tesla (T). Catheter force transmission and balloon-burst pressure of the MR-tracking PTA catheter were compared with those of a standard PTA catheter. The dilatative capability of the angioplasty balloon was assessed in vitro as well as in vivo, in an isolated femoral artery segment in a swine. Results: The degree of heating at the RF coil was directly proportional to the power of the RF pulses. Heating was negligible with MR tracking, conventional spin-echo and low-flip gradient-echo sequences. Sequences with higher duty cycles, such as fast spin echo, produced harmful heating effects. Force transmission of the MR-tracking PTA catheter was slightly inferior to that of the standard PTA catheter, while balloon-burst pressures were similar to those of conventional catheters. The MR-tracking PTA catheter functioned well both in vitro and in vivo. Conclusion: The in vivo use of an MR-tracking PTA catheter is safe under most scanning conditions.

Acute gastrointestinal bleeding: detection of source and etiology with multi-detector-row CT

This study was conducted to determine the ability of multi-detector-row computed tomography (CT) to identify the source and etiology of acute gastrointestinal bleeding. Eighteen patients with acute upper (n = 10) and lower (n = 8) gastrointestinal bleeding underwent 4-detector-row CT (n = 6), 16-detector-row CT (n = 11), and 64-slice CT (n = 1) with an arterial and portal venous phase of contrast enhancement. Unenhanced scans were performed in nine patients. CT scans were reviewed to determine conspicuity of bleeding source, underlying etiology, and for potential causes of false-negative prospective interpretations. Bleeding sources were prospectively identified with CT in 15 (83%) patients, and three (17%) bleeding sources were visualized in retrospect, allowing the characterization of all sources of bleeding with CT. Contrast extravasation was demonstrated with CT in all 11 patients with severe bleeding, but only in 1 of 7 patients with mild bleeding. The etiology could not be identified on unenhanced CT scans in any patient, whereas arterial-phase and portal venous-phase CT depicted etiology in 15 (83%) patients. Underlying etiology was correctly identified in all eight patients with mild GI bleeding. Multi-detector-row CT enables the identification of bleeding source and precise etiology in patients with acute gastrointestinal bleeding.

Complete replacement of open repair for ruptured abdominal aortic aneurysms by endovascular aneurysm repair : a two-center 14-year experience

Objective:To present the combined 14-year experience of 2 university centers performing endovascular aneurysm repair (EVAR) on 100% of noninfected ruptured abdominal aortic aneurysms (RAAA) over the last 32 months. Background:Endovascular aneurysm repair for RAAA feasibility is reported to be 20% to 50%, and EVAR for RAAA has been reported to have better outcomes than open repair. Methods:We retrospectively analyzed prospectively gathered data on 473 consecutive RAAA patients (Zurich, 295; Örebro, 178) from January 1, 1998, to December 31, 2011, treated by an “EVAR-whenever-possible” approach until April 2009 (EVAR/OPEN period) and thereafter according to a “100% EVAR” approach (EVAR-ONLY period).Straightforward cases were treated by standard EVAR. More complex RAAA were managed during EVAR-ONLY with adjunctive procedures in 17 of 70 patients (24%): chimney, 3; open iliac debranching, 1; coiling, 8; onyx, 3; and chimney plus onyx, 2. Results:Since May 2009, all RAAA but one have been treated by EVAR (Zurich, 31; Örebro, 39); 30-day mortality for EVAR-ONLY was 24% (17 of 70). Total cohort mortality (including medically treated patients) for EVAR/OPEN was 32.8% (131 of 400) compared with 27.4% (20 of 73) for EVAR-ONLY (P = 0.376). During EVAR/OPEN, 10% (39 of 400) of patients were treated medically compared with 4% (3 of 73) of patients during EVAR-ONLY. In EVAR/OPEN, open repair showed a statistically significant association with 30-day mortality (adjusted odds ratio [OR] = 3.3; 95% confidence interval [CI], 1.4–7.5; P = 0.004). For patients with no abdominal decompression, there was a higher mortality with open repair than EVAR (adjusted OR = 5.6; 95% CI, 1.9–16.7). In patients with abdominal decompression by laparotomy, there was no difference in mortality (adjusted OR = 1.1; 95% CI, 0.3–3.7). Conclusions:The “EVAR-ONLY” approach has allowed EVAR treatment of nearly all incoming RAAA with low mortality and turndown rates. Although the observed association of a higher EVAR mortality with abdominal decompression needs further study, our results support superiority and more widespread adoption of EVAR for the treatment of RAAA.

Open abdomen treatment following endovascular repair of ruptured abdominal aortic aneurysms

BACKGROUND Open abdomen treatment (OAT) is considered a lifesaving procedure in patients with abdominal compartment syndrome (ACS) after endovascular or open intervention for ruptured abdominal aortic aneurysms (RAAA). Standardized treatment methods and algorithms for its use are still lacking. The high, published mortality rates may reflect difficulties in detecting and treating ACS, especially in patients treated by emergency endovascular aneurysm repair (eEVAR). Presented are standardized algorithms for OAT, including a new technique using the vacuum-assisted closure (VAC) system developed during 10 years of experience with eEVAR for RAAA. METHODS We retrospectively analyzed 102 patients with RAAA treated by eEVAR from January 1998 to April 2008. Abdominal decompression was done when intravesical pressure >20 mm Hg or when abdominal perfusion pressure was <50 to 60 mm Hg and concomitant organ deterioration occurred. OAT was initially done with a subcutaneously sutured plastic bag or with a nonsutured zipper drape combined with a VAC device (VAC/ETHIZIP; KCI International Inc, Amstelveen, The Netherlands; Ethicon, Somerville, NJ). All patients were switched to VAC/ETHIZIP as soon as possible. Dressings were generally changed every 3 to 5 days. Intra-abdominal pressure was monitored until stability was observed after delayed direct abdominal closure. RESULTS Overall 30-day mortality for eEVAR was 13% (13 of 102); 8% (7 of 82) for patients without ACS and 30% (6 of 20) for those with ACS. Decompression for ACS was needed in 20 patients (20%) primarily during the intervention (n = 14) or secondarily in the intensive care unit (n = 6). Six of 20 (30%) patients requiring OAT died <or=30 days (4 primary, 2 secondary). A mean of 3.6 (range, 1-12) planned second-look interventions were done per patient at an interval of 3 to 5 days. No bowel lesions were observed. Four patients required antibiotic therapy for abdominal infection, and all infections resolved. Delayed abdominal wall closure (direct closure, 11; closure with polypropylene mesh, 3; bilateral anterior rectus abdominis sheath turnover flap, 1) was achieved after a median of 6 days (range, 1-47 days). CONCLUSION The use of standardized novel techniques and a treatment protocol and algorithm for OAT after eEVAR for RAAA were feasible and safe. It decreased the workload of the medical and nursing staff, enhanced patient comfort because the need for dressing changes was minimized, and likely contributed to lower overall mortality in RAAA patients. Delayed direct fascial closure was possible in most patients.