Hanno Hoppe's scientific contributionswhile working at Inselspital, Universitätsspital Bern, Berna, Bern, Switzerlandand other institutions
- [Show abstract] ABSTRACT: Purpose To evaluate the efficacy of superselective transcatheter arterial embolization (TAE) in the treatment of acute peripancreatic bleeding complications. Methods During a 9-year period, 44 patients with acute bleeding of the peripancreatic arteries underwent TAE in our institution. Thirty-eight patients were treated using microcatheters and 6 patients with a diagnostic catheter. Embolic agents included coils (n = 38), polyvinyl alcohol (PVA) particles (n = 2), isobutyl cyanoacrylate (n = 2), coils plus PVA particles (n = 1), and coils plus isobutyl cyanoacrylate (n = 1). Outcome measures included technical success, clinical success, and the rate of complications. Results Identified bleeding sources included gastroduodenal artery (n = 14), splenic artery (n = 9), pancreaticoduodenal artery (n = 6), common hepatic artery (n = 5), superior mesenteric artery branches (n = 4), proper hepatic artery (n = 3), and dorsal/transverse pancreatic artery (n = 3). Technical success with effective control of active bleeding was achieved in 41/44 patients (93 %). Clinical success attributed to TAE alone was documented in 40/44 patients (91 %). The rate of major complications was 2 % including death in one patient. Conclusions Superselective TAE allows effective, minimally invasive control of acute peripancreatic bleeding complications with a low rate of therapeutically relevant complications.
- [Show abstract] ABSTRACT: Virtual endoscopy of the upper, central and peripheral airways (virtual laryngoscopy or virtual bronchoscopy) produces endoluminal images similar to those of fiberoptic endoscopy. In particular, virtual endoscopy is useful for the assessment of endoluminal tumor extent and tracheobronchial stenosis. Especially since the introduction of multirow detector CT, high-resolution virtual-endoscopic images of the airways can be reconstructed. Either surface rendering or volume rendering can be used for realistic depiction of the airways. Semitransparent color-coded volume rendering is advantageous, because adjacent structures can be displayed in addition to endoluminal views. A major advantage of virtual endoscopy over fiberoptic endoscopy is its non-invasiveness. With virtual endoscopy, even a high-grade stenosis is passable, enabling evaluation of the distal airways. Disadvantages are its inability to depict mucosal color and to perform therapeutic maneuvers. In comparison to other CT display modes, virtual endoscopy allows a more realistic assessment of tracheobronchial stenosis than axial CT slices and multiplanar reformats. Virtual endoscopy of the airways can be used complementary to fiberoptic endoscopy before tracheotomy, stent implantation or lung resection and for post-operative follow-up. In the future, virtual airway endoscopy will be increasingly applied for interactive virtual reality guidance of airway procedures such as bronchoscopy and surgery.
- [Show abstract] ABSTRACT: Background and purpose: Conventional platinum coils cause imaging artifacts that reduce imaging quality and therefore impair imaging interpretation on intraprocedural or noninvasive follow-up imaging. The purpose of this study was to evaluate imaging characteristics and artifact production of polymeric coils compared with standard platinum coils in vitro and in vivo. Materials and methods: Polymeric coils and standard platinum coils were evaluated in vitro with the use of 2 identical silicon aneurysm models coiled with a packing attenuation of 20% each. DSA, flat panel CT, CT, and MR imaging were performed. In vivo evaluation of imaging characteristics of polymeric coils was performed in experimentally created rabbit carotid bifurcation aneurysms. DSA, CT/CTA, and MR imaging were performed after endovascular treatment of the aneurysms. Images were evaluated regarding visibility of individual coils, coil mass, artifact production, and visibility of residual flow within the aneurysm. Results: Overall, in vitro and in vivo imaging showed relevantly reduced artifact production of polymeric coils in all imaging modalities compared with standard platinum coils. Image quality of CT and MR imaging was improved with the use of polymeric coils, which permitted enhanced depiction of individual coil loops and residual aneurysm lumen as well as the peri-aneurysmal area. Remarkably, CT images demonstrated considerably improved image quality with only minor artifacts compared with standard coils. On DSA, polymeric coils showed transparency and allowed visualization of superimposed vessel structures. Conclusions: This initial experimental study showed improved imaging quality with the use of polymeric coils compared with standard platinum coils in all imaging modalities. This might be advantageous for improved intraprocedural imaging for the detection of complications and posttreatment noninvasive follow-up imaging.
- [Show abstract] ABSTRACT: Purpose: Selective internal radiotherapy (SIRT) with the beta emitter Yttrium-90 is a rapidly developing therapy option for liver malignancies. SIRT has emerged as a new therapeutic concept for the palliative treatment of primary and secondary liver tumors not suitable for surgery, chemotherapy or percutaneous tumor ablation. The purpose of this retrospective study was to evaluate the clinical and radiological response of patients with non-resectable liver tumors after SIRT. Material and Methods: Over a two-year period 58 patients with advanced liver disease were selected by a multidisciplinary tumor board as candidates to receive SIRT. Clinical and radiological follow-up were performed by CT and/or MRI at one and three months, and every three months thereafter. Patients' survival, response to treatment (RECIST 1.0 and mRECIST) and clinical outcome were assessed. Results: SIRT was performed according to interventional and nuclear medical guidelines in 53 of 58 (91%) eligible patients. Overall survival after 3, 6 and 12 months was 90.5%, 71.4% and 43.8% respectively. Fifteen of 53 (28%) patients died during the observation period. So far, radiological tumor response in 40 out of 53 patients showed complete remission in 0%, partial remission in 27.3%, stable disease in 63.6 % and tumor size progression in 9.0%. Seven patients were eligible for further downsizing by a second SIRT, chemoembolization or surgical resection. The majority of patients showed no treatment-related clinical symptoms. However, there was one severe adverse event related to ulceration from non-targeted deposition of SIR-spheres with life-threatening consequences. Conclusion: SIRT provides a promising tumor response even in advanced cases of liver disease.
- [Show abstract] ABSTRACT: The purpose of this study was to simulate pulmonary emboli (PE) and image quality at low tube energy and reduced contrast material volume in normal-dose pulmonary CT angiography (CTA) images and to analyze the diagnostic accuracy with normal- and low-dose pulmonary CTA. Normal-dose pulmonary CTA examinations using 120 kVp and 100 mL of contrast material in 10 patients with no PE were retrospectively selected. The image characteristics of an 80-kVp low-dose pulmonary CTA protocol (patient exposure reduction, 57%) with 75 mL of contrast material were simulated. Four different sets of filling defects were computer simulated in identical locations in each normal-dose and corresponding low-dose examination, equaling 783 PE in 40 normal-dose and 40 low-dose datasets. Ten normal-dose and 10 low-dose examinations contained no emboli and were used as controls. The 100 pulmonary CTA studies were randomly assessed by three readers blinded to PE location and image quality. The results were assessed by nonparametric tests and Student t tests. No difference was found between the CT protocols in terms of sensitivity, specificity, and positive and negative diagnostic likelihood ratios at all ramification levels of the pulmonary arteries (p = 0.343-1). The overall sensitivity and specificity with the normal and simulated low-dose protocols were 79.9% versus 81.3% and 98.0% versus 98.2% (p = 0.444 and 0.702), respectively. The diagnostic confidence (2.81 ± 0.39 vs 2.77 ± 0.47; p = 0.297) and overall image quality (3.92 ± 0.52 vs 3.83 ± 0.54; p = 0.216) were similar at 120 kV and 80 kV. The intraindividual comparison of diagnostic accuracy with normal-dose and simulated low-dose pulmonary CTA protocols revealed no difference under experimental conditions.
- [Show abstract] ABSTRACT: Comparison of arterial and venous coronary artery bypass flow measurements using 3-T magnetic resonance (MR) phase contrast in correlation with intraoperative Doppler flow measurements. Fifty-six coronary bypasses (right coronary artery n=18, left internal mammary artery to left anterior descending artery n=16, marginal artery n=7, circumflex artery n=7, diagonal artery n=6, left anterior descending artery n=1, and right internal mammary artery to right coronary artery n=1) were studied in 27 asymptomatic patients. In this prospective study, each bypass was studied intra-operatively using Doppler flow measurement. Within one week post surgery, patients were studied using a 3-T MR scanner (Magnetom Verio, Siemens, Erlangen, Germany) using velocity encoded phase-contrast flow measurements. Intraoperative Doppler flow measurements demonstrated regular flow patterns in all vascular territories supplied. All bypasses were patent on MRI and flow measurement results were as follows: median flow 60ml/min (interquartile range (IQR): 37.5-78.5ml/min). For comparison, the corresponding median intraoperative flow was 58ml/min (IQR: 41-80ml/min) (p<0.001; R=0.44). Linear regression analysis demonstrated a significant correlation for venous bypasses (p=0.0002; R=0.48), but not for arterial bypasses (p=0.09; R=0.24). This study demonstrated that MR flow measurements of venous bypass grafts agreed more with Doppler than arterial bypass grafts. However, bypass patency was confirmed for all patients. In the future, this technique may be used for non invasive coronary bypass graft follow-up.
- [Show abstract] ABSTRACT: To assess if finite element (FE) models can be used to predict deformation of the femoropopliteal segment during knee flexion. Magnetic resonance angiography (MRA) images were acquired on the lower limbs of 8 healthy volunteers (5 men; mean age 28 ± 4 years). Images were taken in 2 natural positions, with the lower limb fully extended and with the knee bent at ~ 40°. Patient-specific FE models were developed and used to simulate the experimental situation. The displacements of the artery during knee bending as predicted by the numerical model were compared to the corresponding positions measured on the MRA images. The numerical predictions showed a good overall agreement between the calculated displacements of the motion measures from MRA images. The average position error comparing the calculated vs. actual displacements of the femoropopliteal intersection measured on the MRA was 8 ± 4 mm. Two of the 8 subjects showed large prediction errors (average 13 ± 5 mm); these 2 volunteers were the tallest subjects involved in the study and had a low body mass index (20.5 kg/m²). The present computational model is able to capture the gross mechanical environment of the femoropopliteal intersection during knee bending and provide a better understanding of the complex biomechanical behavior. However, results suggest that patient-specific mechanical properties and detailed muscle modeling are required to provide accurate patient-specific numerical predictions of arterial displacement. Further adaptation of this model is expected to provide an improved ability to predict the multiaxial deformation of this arterial segment during leg movements and to optimize future stent designs.
- [Show abstract] ABSTRACT: The purpose of this article is to assess the impact of large patient size on the detection of hypovascular liver tumors with MDCT and the effect of a noise filter on image quality and lesion detection in obese patients. A liver phantom with 45 hypovascular tumors (diameters of 5, 10, and 15 mm) was placed into two water containers mimicking intermediate and large patients. The containers were scanned with a 64-MDCT scanner. The CT dataset from the large phantom was postprocessed using a noise filter. The image noise was measured and the contrast-to-noise ratio (CNR) of the tumors was calculated. Tumor detection was independently performed by three radiologists in a blinded fashion. The application of the noise filter in the large phantom yielded a reduction of image noise by 42% (p < 0.0001). The CNR values of the tumors in the nonfiltered and filtered large phantom were lower than that in the intermediate phantom (p < 0.05). In the non-filtered and filtered large phantom, 25% and 19% fewer tumors, respectively, were detected on average compared with the intermediate phantom (p < 0.01). The risk of missing hypovascular liver tumors with CT is substantially increased in large patients. A noise filter improves image quality in obese patients.
- [Show abstract] ABSTRACT: The superior vena cava syndrome (SVCS) comprises various symptoms due to occlusion of the SVC, which can be easily obstructed by pathological conditions (eg, lung cancer, due to the low internal venous pressure within rigid structures of the thorax [trachea, right bronchus, aorta]). The resulting increased venous pressure in the upper body may cause edema of the head, neck, and upper extremities, often associated with cyanosis, plethora, and distended subcutaneous vessels. Despite the often striking clinical presentation, SVCS itself is usually not a life-threatening condition. Currently, randomized controlled trials on many clinically important aspects of SVCS are lacking. This review gives an interdisciplinary overview of the pathophysiology, etiology, clinical manifestations, diagnosis, and treatment of malignant SVCS.
- [Show abstract] ABSTRACT: Evaluation of a novel non-invasive tool for postoperative follow-up of patients postelective saphenous vein coronary artery bypass graft (CABG) was performed. Ten patients were included. Their bypass grafts supplied the right coronary artery (7), marginal branches (1), diagonal branches (2), and the circumflex artery (n=1). Each bypass was examined intraoperatively using Doppler flow measurement. Patients were examined with a 3-Tesla magnetic resonance imaging (MRI) scanner (MAGNETOM Verio, Siemens, Erlangen, Germany) within one week postsurgery using MR-angiography with an intravasal contrast agent and velocity encoded phase-contrast flow measurements. Intraoperative Doppler flow measurements revealed regular flow patterns in all vascular territories supplied. The median intraoperative flow rate was 50 ml/min with an inter-quartile range (IQR) of 42-70 ml/min. The clinical postoperative course was uneventful. MRI showed all grafts to be patent. The median postoperative flow rate was 50 ml/min (IQR: 32-65 ml/min). MRI flow rates agreed well with intraoperative Doppler flow measurements (mean difference: -2.8±20.1 ml/min). This initial study demonstrates that 3-Tesla MRI flow measurements correlated well with Doppler thus reconfirming the graft patency postCABG. Further refinement and broader application of this technique may facilitate follow-up postCABG potentially replacing empiric clinical judgment by reliable non-invasive imaging.
- [Show abstract] ABSTRACT: BACKGROUND; Hemoptysis can be an acute medical emergency, which can be localized angiographically and controlled by therapeutic intervention. To evaluate the effectiveness and safety of bronchial artery embolization, and including follow-up in patients with hemoptysis. Thirty-five vascular interventions were performed in 28 patients (nine women and 19 men, mean age 42 years, age range 20-82 years) treated for hemoptysis between January 1998 and October 2008. Underlying diseases were cystic fibrosis (n = 9), lung cancer (n = 6), chronic inflammatory disease (n = 4), bronchiectasis (n = 3), chronic obstructive pulmonary disease (n = 2), and other (n = 4). Bronchial artery embolization was performed using particles. Patients were followed up for a median of 23 months (range 1 month to 8 years). Bronchial artery embolization was technically successful in all patients (bleeding halted within 24 hours). Recurrent bleeding occurred in four patients with cystic fibrosis (14%) at one, 16, 19 and 48 months, respectively. Within this subset, multirecurrence bleeding occurred in one patient with cystic fibrosis. Cumulative patient survival rate was 74% at eight years. No patient died due to hemoptysis but due to underlying disease. Bronchial artery embolization was highly effective in patients with hemoptysis. It may help to avoid surgery in patients who are poor candidates for surgery. Should hemoptysis recur in these patients, repeated embolization can be performed.
- [Show abstract] ABSTRACT: Preoperative mapping of the arterial spinal supply prior to thoracoabdominal aortic aneurysm repair is highly relevant because of high risk for postoperative ischemic spinal cord injuries such as paraparesis or paraplegia. Twenty-four consecutive patients prior to surgical thoracoabdominal aortic aneurysm repair were investigated. All patients underwent steady-state MR angiography (MRA) of the spinal vasculature with 3-T MRI. The sequence used was a steady-state coronary 3D FLASH with 0.7-mm isotropic voxels. MRA was performed using an intravasal contrast agent. Studies were evaluated by three readers including delineation of arterial spinal supply including both aortic origin and spinal canal entry by three readers. Identification and localization of the Adamkiewicz artery and its spinal canal entry was successful in all patients. Overall depiction of the vascular anatomy was graded as very good in 3 (12.5%), good in 14 (58.4%), sufficient in 5 (20.8%), and poor in 2 (8.3%) patients. Depiction of segmental artery aortic exit level was graded as good in 6 (25.0%), sufficient in 10 (41.7%), poor in 4 (16.7%) and not identifiable in 4 (16.7%) patients. Delineation of segmental artery entry level into the spinal canal was graded as very good in 4 (16.7%), good in 11 (45.8%), sufficient in 6 (25.0%), and poor in 3 (12.5%) patients. The use of 3-T MRA with an intravascular contrast agent and steady-state enables AKA localization including its segmental arteries with regard to the level of aortic origin and spinal canal entry in most patients.
- [Show abstract] ABSTRACT: To evaluate the effectiveness and safety of covered stents for the management of iatrogenic arterial injury. Between 03 / 1998 and 12 / 2009, 31 patients underwent selective covered stent implantation after iatrogenic arterial injury. 12 / 31 of these patients (38.7 %) were hemodynamically unstable. Six different endovascular covered stent types were utilized. The primary endpoints of this study were technical and clinical success and rates of minor and major complications. Initial angiograms demonstrated active extravasation in 19 (61.3 %) patients and pseudoaneurysms in 12 (38.7 %) patients. The following sites of bleeding origin were detected: axillary artery, subclavian artery, common iliac artery, external iliac artery, internal iliac artery, common femoral artery, superficial femoral artery, popliteal and fibular artery, femoro-popliteal and popliteo-crural bypasses, common hepatic artery, aberrant hepatic artery, cystic and gastroduodenal artery. In all patients bleeding was effectively controlled by covered stent implantation resulting in an immediate technical success of 100 %. Clinical success attributed to covered stent implantation was documented in 30 of the 31 patients (96.8 %). Major complications included death in four patients (11.1 %), acute thrombosis with arm ischemia in one patient (2.8 %) and stent fracture with associated pseudoaneurysm in another patient (2.8 %). In 2 / 31 patients (6.5 %) covered stent failure was detected and successfully treated by implantation of a second covered stent. Emergency and elective implantation of covered stents may be used for minimally invasive and effective management of iatrogenic arterial injury.
Article: Vascular Malformations[Show abstract] ABSTRACT: Vascular malformations are rare and should be assigned to the care of a vascular specialist. Modern medicine allows precise diagnosis and classification of these lesions. Syndromic names of vascular malformations do not provide the necessary descriptive precision of these lesions and should be avoided for diagnosis since precise classification is important for therapeutic decisions. Local and systemic affection must be considered for clinical and prognostic evaluation of vascular malformations. They serve to establish a therapeutic concept that aims to provide sufficient disease control and quality of life. Most patients require ongoing follow up and repetitive treatment. They should be followed in experienced vascular centers providing a multidisciplinary care.
- [Show abstract] ABSTRACT: Endovascular treatment is an increasingly used therapeutic option in patients with chronic atherosclerotic occlusive mesenteric disease. Purpose of this study was evaluation of patency and mortality in patients treated with visceral artery percutaneous transluminal angioplasty (PTA) or stenting including follow-up. A retrospective review of 17 consecutive patients (4 women, 13 men) with endovascular treatment for symptomatic chronic mesenteric ischemia from 1998 to 2004 was performed. Mean follow-up period was 42 months. Patient demographics, interventional details, primary and/or secondary patency and mortality were recorded. Cumulative mortality and patency rates were determined using Kaplan-Meier life table analysis. Twenty-six interventions (PTA alone n=13, PTA and stenting n=13) were performed in 17 patients. Interventions were performed in the superior mesenteric artery (n=13) and celiac artery (n=13). The re-intervention rate was 30% (6/26). Re-interventions were performed for the superior mesenteric artery (n=4) and celiac artery (n=2). Cumulative overall 1-year results were primary patency rate 81%, secondary patency rate 94%, and survival rate 82%. Cumulative 10-year results were primary patency rate 73%, secondary patency rate 94%, and survival rate 65%. The 10-year secondary patency rate was 100% in patients post initial stenting and 86% in patients post initial PTA. Long-term follow-up post endovascular treatment for chronic mesenteric ischemia demonstrated a considerable overall secondary patency rate of 94%. However, the long-term secondary patency rate was higher in patients post initial stenting compared to PTA alone.
- [Show abstract] ABSTRACT: Delayed occlusion time in parent artery occlusion of brain-supplying vessels might carry risk for thromboembolic complications. Vascular plug devices are successfully used in cardiopulmonary and peripheral interventions to occlude high-flow lesions and have been adapted for use in neurointerventions. The purpose of the present study was to experimentally evaluate the immediate occlusion time of the AMPLATZER vascular plug (AVP) II-a second-generation cylindrical, self-expandable, resheathable nitinol wire mesh consisting of three lobes-in the carotid artery. AVP II devices (N = 12) 6 mm in diameter (length, 6 mm) were deployed through 6-F guiding catheters in the common carotid arteries of two pigs. After device deployment, angiography was performed to measure the time interval until no contrast agent opacification was visible distal to the AVP II, indicating complete flow cessation and occlusion of the distal vessel. Vessel diameters before deployment and after resheathing of the device were measured. Device navigation, positioning, recapturing, vasospasm, and angiographic signs of vessel injury were assessed. The mean time to total flow cessation and occlusion was 57.9 seconds (median, 44 s ± 27 [SD]; range, 26-104 s). Device navigation, positioning, and resheathing were successful in all cases. There was neither significant vasospasm nor vessel injury visible on angiography. Application and retrieval of the second-generation AVP II are uncomplicated and the device is able to achieve fast and sufficient cessation of flow in a hemodynamically comparable setting to the human carotid artery, indicating some potential to fill a gap in the neurointerventional tool box.
- [Show abstract] ABSTRACT: It is unknown whether sorafenib can be combined with transarterial chemoembolization (TACE) in patients with hepatocellular carcinoma. This study assesses the safety and tolerability of a continuous regimen of sorafenib combined with TACE. This was an open-label phase I study testing a continuous administration of sorafenib (dose escalation from 200 mg twice daily [bid] to 400 mg bid) starting 7 days prior to TACE with doxorubicin (50 mg). Twenty-one patients were screened and 14 received sorafenib combined with TACE. Because there were no dose-limiting toxicities in the first three patients who received sorafenib at a dose of 200 mg bid, subsequent patients received 400 mg bid. Twenty-seven procedures were performed (median, two per patient) and two local therapy-related severe adverse events occurred. The median duration of sorafenib therapy was 246 days (range, 14-547 days). Sorafenib-related adverse events of grade ≥3 were hand-foot skin reaction (n = 3), weight loss (n = 2), diarrhea (n = 1), abdominal pain (n = 1), and thrombocytopenia (n = 3). After treatment with sorafenib and TACE, there was a significant decrease in the concentration of plasma vascular endothelial growth factor (VEGF) from 93 ng/l to 67 ng/l. Continuous administration of sorafenib at a dose of 400 mg bid combined with TACE was tolerable. The adverse event profile of this regimen was comparable with that of sorafenib monotherapy with the exception of thrombocytopenia, which may be more frequent. There were no increases in the circulating VEGF levels after TACE with this combined regimen. (Swiss Association for the Study of the Liver study number 25; ClinicalTrials.gov trial identifier, NCT00478374).
- [Show abstract] ABSTRACT: The latest-generation Amplatzer vascular plug (AVP), the AVP 4, is designed for embolization of smaller vessels without a sheath or guiding catheter. This study evaluated the AVP 4 in peripheral vascular embolization. Embolization with the AVP 4 was attempted in 13 patients (11 men) for trauma (n = 7) and other indications (n = 6). Technical success rate, vascular bed, size of catheter, and number and size of AVP 4 devices were recorded. Embolization with the AVP 4 was successful in 10 of 13 patients (77%). In trauma patients (n = 7), embolization of the splenic artery (n = 4), lumbar artery (n = 2), and superior gluteal artery (n = 1) was performed. In other patients, preoperative embolization of the right portal vein (n = 1), a gastric varix after transjugular intrahepatic portosystemic shunt creation (n = 1), an aneurysm of the internal iliac artery (n = 1), and inferior mesenteric artery (IMA) embolization before aneurysm repair (n = 2) was performed. Sizes of the AVP 4 were 4 mm (n = 6), 6 mm (n = 5), and 8 mm (n = 1). In all patients, 4- and 5-F catheters with a 0.038-inch minimum inner lumen were used. In one patient, IMA embolization was attempted via a femoral approach but was unsuccessful as a result of repeated catheter tip dislocation because of acute angle; coils were used instead. Peripheral embolization with the AVP 4 was successful in the majority of patients. Future comparative study is necessary to evaluate this device's benefits over other embolization materials such as earlier-generation AVPs or microcoils.
Inselspital, Universitätsspital BernBerna, Bern, Switzerland