Alexander Massmann

MR angiography for detection of pulmonary arteriovenous malformations in patients with hereditary hemorrhagic telangiectasia.

OBJECTIVE The purpose of our study was to evaluate contrast-enhanced MR angiography (CE-MRA) as a screening procedure for the detection of pulmonary arteriovenous malformations (AVMs) in patients with hereditary hemorrhagic telangiectasia (HTT). MATERIALS AND METHODS Two hundred three consecutive subjects (patients with diagnosed HHT or first-degree relatives; 87 males, 116 females; 6-83 years old) underwent pulmonary CE-MRA with 0.1 mmol/kg of gadobenate dimeglumine. The presence of pulmonary AVM was scored as 0 (none present), 1 (definitely present), or 2 (uncertain) and was evaluated by patient sex and pulmonary AVM size (< 5, 5-10, 11-15, 16-20, > 20 mm). Patients scored as 1 or 2 with at least one pulmonary AVM of > or = 5 mm underwent conventional pulmonary angiography for possible embolization. Pulmonary AVM detection on CE-MRA and pulmonary angiography was compared using paired Students t tests. RESULTS The presence of pulmonary AVM was considered definite in 56 of 203 (27.6%) patients and uncertain in one of 203 patients on CE-MRA. Of 156 pulmonary AVMs detected on CE-MRA, 124 (49 in 27 males, 75 in 30 females) were detected on first screening CE-MRA and 32 on follow-up CE-MRA. Pulmonary AVMs on CE-MRA were solitary in 25 patients, multiple in 31 patients, and predominantly small (< 5 mm, n = 32; 5-10 mm, n = 45). Significantly (p < 0.0001) fewer pulmonary AVMs were detected on pulmonary angiography (76/96 [79.2%] evaluable pulmonary AVMs in 40 patients before first pulmonary angiography; 92/119 [77.3%] pulmonary AVMs overall). Three-dimensional maximum-intensity-projection reconstructions permitted improved pulmonary AVM visualization and embolization planning of complex pulmonary AVMs. CONCLUSION CE-MRA is suitable for screening patients with HHT. It permits accurate detection and staging of pulmonary AVMs, appropriate differentiation of lesions requiring embolization and accurate orientation, and visualization and planning of embolization therapy.

Paclitaxel-coated balloon angioplasty for symptomatic central vein restenosis in patients with hemodialysis fistulas.

Purpose: To report a retrospective observational analysis of standard balloon angioplasty (BA) vs. paclitaxel-coated balloon angioplasty (PCBA) for symptomatic central vein restenoses in patients with impaired native hemodialysis fistulas. Methods: A retrospective review was conducted of 27 consecutive patients (15 men; mean age 66±13.8 years, range 39–90) with 32 central vein stenoses (CVS; 6 axillary, 11 subclavian, 12 brachiocephalic, and/or 3 superior caval veins) treated successfully using BA. Freedom from reintervention after BA of de novo lesions was 7.4±7.9 months (range 1–24). Twenty-five (92.6%) patients developed symptomatic restenoses and were treated one or more times by BA (n=32) or PCBA (n=20) using custom-made paclitaxel-coated balloons (diameter 6–14 mm). Results: Technical (<30% residual stenosis) and clinical (functional fistula) success rates for the initial and secondary angioplasty procedures were 100%. No minor/major procedure-associated complications occurred. Mean follow-up was 18.4±17.5 months. Kaplan-Meier analysis for freedom from target lesion revascularization (TLR) found PCBA superior to BA (p=0.029). Median freedom from TLR after BA was 5 months; after PCBA, >50% of patients were event-free during the observation period (mean freedom from TLR 10 months). Restenosis intervals were prolonged by PCBA (median 9 months) vs. BA (median 4 months; p=0.023). Conclusion: Paclitaxel-coated balloon angioplasty of central vein restenosis in patients with hemodialysis shunts yields a statistically significant longer freedom from TLR compared to standard balloon angioplasty.

Transarterial chemoembolization (TACE) for colorectal liver metastases—current status and critical review

BackgroundTransarterial liver-directed therapies are currently not recommended as a standard treatment for colorectal liver metastases. Transarterial chemoembolization (TACE), however, is increasingly used for patients with liver-dominant colorectal metastases after failure of surgery or systemic chemotherapy. The limited available data potentially reveals TACE as a valuable option for pre- and post-operative downsizing, minimizing time-to-surgery, and prolongation of overall survival after surgery in patients with colorectal liver only metastases.PurposeIn this overview, the current status of TACE for the treatment of liver-dominant colorectal liver metastases is presented. Critical comments on its rationale, technical success, complications, toxicity, and side effects as well as oncologic outcomes are discussed. The role of TACE as a valuable adjunct to surgery is addressed regarding pre- and post-operative downsizing, conversion to resectability as well as improvement of the recurrence rate after potentially curative liver resection. Additionally, the concept of TACE for liver-dominant metastatic disease with a focus on new embolization technologies is outlined.ConclusionsThere is encouraging data with regard to technical success, safety, and oncologic efficacy of TACE for colorectal liver metastases. The majority of studies are non-randomized single-center series mostly after failure of systemic therapies in the 2nd line and beyond. Emerging techniques including embolization with calibrated microspheres, with or without additional cytotoxic drugs, degradable starch microspheres, and technical innovations, e.g., cone-beam computed tomography (CT) allow a new highly standardized TACE procedure. The real efficacy of TACE for colorectal liver metastases in a neoadjuvant, adjuvant, and palliative setting has now to be evaluated in prospective randomized controlled trials.

Uncovered stent implantation in complicated acute aortic dissection type B

OBJECTIVE To retrospectively evaluate the technical feasibility and midterm results of uncovered thoracoabdominal stent placement in complicated acute aortic dissection Stanford type B (cAADB). PATIENTS AND METHODS Fourteen consecutive patients (3 females; range, 44-71 years) with cAADB who had symptomatic gastrointestinal malperfusion and claudication underwent immediate uncovered stent implantation (diameter, 7-28 mm; length, 40-100 mm) into the true lumen of the thoracoabdominal aorta (n = 23) and visceral arteries (n = 5). RESULTS Stenting resulted in elimination of gastrointestinal ischemia and symptoms in 13 of 14 patients; persisting symptoms led to secondary surgical revascularization in only 1 patient. More than 1 stent (≤ 4) was placed in 7 patients (2 celiac, 1 mesenteric, 2 renal, 8 aorto-iliac). Follow-up computed tomographic angiography (CTA) revealed collapse of 4 aortic stents (diameter, 9-25 mm; length, 100 mm) at 1 week in the absence of symptoms. Balloon reexpansion was possible in all 4 stents, but recollapse occurred within 1 month. Despite stent collapse, the patients remained asymptomatic; ultrasonography and CTA documented sufficient perfusion of the visceral arteries in all patients. Follow-up ranged from 6 months to 5 years (average, 2.5 years). Except for the patient who underwent iliacomesenteric bypass for unspecific abdominal pain, no other patient required additional interventional or surgical therapy. CONCLUSIONS Acute aortic dissection with suspicion of visceral ischemia should prompt for immediate intervention. Thoracoabdominal uncovered stent implantation is a technically feasible and effective minimally invasive approach that provided successful relief of acute visceral ischemia and claudication in cAADB. Stent size should be less than the normal aortic diameter to avoid possible stent collapse.

Transarterial embolization (TAE) as add-on to percutaneous radiofrequency ablation (RFA) for the treatment of renal tumors: Review of the literature, overview of state-of-the-art embolization materials and further perspective of advanced image-guided tumor ablation

Percutaneous radiofrequency ablation (RFA) for the treatment of stage I renal cell carcinoma has recently gained significant attention as the now available long-term and controlled data demonstrate that RFA can result in disease-free and cancer-specific survival comparable with partial and/or radical nephrectomy. In the non-controlled single center trials, however, the rates of treatment failure vary. Operator experience and ablation technique may explain some of the different outcomes. In the controlled trials, a major limitation is the lack of adequate randomization. In case reports, original series and overview articles, transarterial embolization (TAE) before percutaneous RFA was promising to increase tumor control and to reduce complications. The purpose of this study was to systematically review the literature on TAE as add-on to percutaneous RFA for renal tumors. Specific data regarding technique, tumor and patient characteristics as well as technical, clinical and oncologic outcomes have been analyzed. Additionally, an overview of state-of-the-art embolization materials and the radiological perspective of advanced image-guided tumor ablation (TA) will be discussed. In conclusion, TAE as add-on to percutaneous RFA is feasible and very effective and safe for the treatment of T1a tumors in difficult locations and T1b tumors. Advanced radiological techniques and technologies such as microwave ablation, innovative embolization materials and software-based solutions are now available, or will be available in the near future, to reduce the limitations of bland RFA. Clinical implementation is extremely important for performing image-guided TA as a highly standardized effective procedure even in the most challenging cases of localized renal tumors.

Atypical extensive extratemporal hyperpneumatization of the skull base including the cervical spine: case report and review of the literature.

Study Design. Case report and clinical discussion. Objective. To describe a rare case of hyperpneumatization of the skull base including the cervical spine with the atlas bone. Summary of Background Data. Initial imaging studies of physically traumatized patients consist of conventional radiographs. An atypical radiolucency is often misdiagnosed as a primary malignancy or a secondary osteolytic metastasis. Further imaging studies may reveal an underlying atypical hyperpneumatization as a very rare benign differential diagnosis. Pathophysiologically, embryological developmental anomalies as well as an elevated pressure to the middle and inner ear are discussed. Methods. We present a symptomatic 40-year-old man with conventional radiographs, after computed tomography and magnetic resonance imaging examinations. Results. Imaging studies reveal an uncommon radiolucency of the skull base including the atlas bone, free air beneath the mastoid bone, stylomastoid foramen, epidural air adjacent to the atlas bone, and surrounding soft-tissue emphysema. Conclusion. Atypical radiolucency may represent a very rare benign hyperpneumatization of the skull base, which may include the craniocervical junction. Because of microfractures of the thinned and consecutive, less stable bones, this also can lead to free air and soft-tissue emphysema, which has not been described previously. Special care should be taken to identify epidural free air because of a possible communication of the epidural space with the external environment. Harmful activities and especially high-speed trauma could result in fractures of the cervical spine due to decreased stability of the hyperpneumatized bones.

Magnetresonanztomographie und -angiographie der Aorta

When a diseased aorta is to be imaged, the clinical picture and the urgency determine which of the various procedures available is or are used. One of the more recent techniques applied is conventional MR -imaging, and especially contrast-enhanced MR angiography (CE-MRA), which is a noninvasive technique and allows for the combination of conventional imaging, acquisition of physiological parameters and 3D-angiography. In this article technical and clinical aspects of the use of CE-MRA in different diseases affecting the aorta are discussed. Topics covered include congenital malformations of the aorta, acquired disease, and inflammatory conditions.ZusammenfassungBei der Bildgebung von Erkrankungen der Aorta können heute je nach Krankheitsbild und Dringlichkeit unterschiedliche Verfahren zur Anwendung kommen. Neuere Verfahren stellen die konventionelle MR-Tomographie und speziell die kontrastverstärkte MR-Angiographie dar, die nichtinvasiv die Kombination von Anatomie, Akquisition physiologischer Parameter und 3D-Angiographie kombiniert. In diesem Artikel werden sowohl technische als auch klinische Aspekte bei der Anwendung der MR-Tomographie bei Erkrankungen der Aorta diskutiert. Inhaltlich werden sowohl angeborene Fehlbildungen, erworbene Erkrankungen wie auch entzündliche Veränderungen der Aorta dargestellt.AbstractWhen a diseased aorta is to be imaged, the clinical picture and the urgency determine which of the various procedures available is or are used. One of the more recent techniques applied is conventional MR –imaging, and especially contrast-enhanced MR angiography (CE-MRA), which is a nonivasive technique and allows for the combination of conventional imaging, acquisition of physiological parameters and 3D-angiography. In this article technical and clinical aspects of the use of CE-MRA in different diseases affecting the aorta are discussed. Topics covered include congenital malformations of the aorta, acquired disease, and inflammatory conditions.

Endovascular anatomic reconstruction of the iliac bifurcation with covered stentgrafts in sandwich-technique for the treatment of complex aorto-iliac aneurysms

OBJECTIVE Endovascular anatomic reconstruction of iliac artery bifurcation in aorto-iliac aneurysms using commercial stentgrafts in sandwich-technique by bilateral transfemoral approach. METHODS 24 patients (mean 73.8±standard deviation 6.8years) with complex aorto-iliac aneurysms (AAA): n=17; diameter 64±15 [48-100]mm; common-iliac-artery (CIA): n=27; 43±15 [30-87]mm; internal-iliac-artery (IIA): n=14; 28±8 [15-43]mm) were prospectively enrolled for EVAR with preservation of the IIA (n=31; bi-lateral n=7). Maintenance of antegrade flow to IIA by iliac reconstruction was performed in sandwich-technique prior to EVAR. Follow-up of 15.0±10.8 [1-40]months included contrast-enhanced ultrasound and computed-tomography after 1week, 3, 6 and every 12months. RESULTS Initial technical success for anatomic reconstruction of the iliac arteries in 31 instances was 100%. Primary patency of iliac neo-bifurcations was 90.9% (20/22) at 6months and 84.2% (16/19) at 1year. Postprocedural gutter-endoleaks type 1b were obvious in 6.5% (2/31) of cases, which disappeared 3months later. Aortic/iliac aneurysm-size after 1year decreased (>5mm) in 61.5% of patients. No aneurysm-size increase or late rupture occurred. CONCLUSIONS Endovascular reconstruction of the iliac bifurcation with commercial standard stentgrafts is safe and effective. Transfemoral approach allows extension of distal landing zone for EVAR while preserving the internal iliac artery blood-flow, even in unfavorable iliac anatomy.

Percutaneous mechanical atherectomy for treatment of peripheral arterial occlusive disease

Peripheral arterial occlusive disease (PAOD) is still an extremely important politico-economic disease. Diverse treatment procedures exist but the pillars of therapy are changes in lifestyle, such as nicotine abstinence and walking exercise as well as drug therapy. Further therapy options are considered after conventional procedures have been exhausted. These further options consist of improvement of the blood supply by surgical or minimally invasive procedures. The latter therapy options include balloon dilatation and stenting as the most widely used techniques. More recent techniques also used are cryoplasty, laser angioplasty, drug-coated stents or balloons as well as brachytherapy or atherectomy, whereby this list makes no claims to completeness. The multitude of different treatment methods emphatically underlines the fact that no resounding success can be achieved with one single method. The long-term results of both balloon dilatation and stenting techniques show a need for improvement, which elicited the search for additional methods for the treatment of PAOD. Atherectomy represents such an alternative method for treatment of PAOD. Basically, the term atherectomy means the removal of atheroma tissue. For percutaneous atherectomy, in contrast to surgical procedures, it is not necessary to create surgically access to the vessel but accomplishes the atherectomy by means of dedicated systems via a minimally invasive access. There are two basic forms of mechanical atherectomy: directional and rotational systems.ZusammenfassungDie periphere arterielle Verschlusskrankheit (PAVK) stellt nach wie vor eine volkswirtschaftlich überaus bedeutsame Erkrankung dar. Diverse Behandlungsverfahren existieren; Lebensstiländerungen wie Nikotinabstinenz und Gehtraining und auch medikamentöse Therapien machen einen Pfeiler der Therapie aus. Weitere Therapieansätze kommen nach Ausreizen der konventionellen Verfahren zur Anwendung. Sie bestehen in der Verbesserung der Blutversorgung durch chirurgische oder minimalinvasive Verfahren. Unter den letzteren Therapieoptionen können die Ballondilatation und Stentung als die meist verbreiteten Techniken angesehen werden. Aber auch jüngere Techniken wie der Einsatz von Kryoplastie, Laserangioplastie, medikamentenbeschichteten Stents oder Ballons sowie Brachytherapie oder die Atherektomie werden eingesetzt, wobei die Auflistung keinen Anspruch auf Vollständigkeit erhebt. Die Vielzahl der verschiedenen Behandlungsmethoden belegt eindrücklich, dass noch kein durchschlagender Therapieerfolg mit einer einzelnen Methode erzielt werden konnte. So zeigen die beiden Techniken der Ballondilatation und Stentung verbesserungswürdige Langzeitergebnisse, was die Suche nach weiteren Methoden zur Behandlung der PAVK angeregt hat. Die Atherektomie stellt eine solche alternative Behandlungsmethode der PAVK dar. Prinzipiell bezeichnet der Begriff „Atherektomie“ die Entfernung von Atheromgewebe. Die „perkutane Atherektomie“ benötigt hierzu gegenüber chirurgischen Verfahren keine Gefäßeröffnung sondern bewerkstelligt die Atherektomie mittels dedizierter Systeme über einen minimalinvasiven Zugang. Man unterscheidet 2 verschiedene grundsätzliche Typen der mechanischen Atherektomie: direktionale und rotierende Systeme.AbstractPeripheral arterial occlusive disease (PAOD) is still an extremely important politico-economic disease. Diverse treatment procedures exist but the pillars of therapy are changes in lifestyle, such as nicotine abstinence and walking exercise as well as drug therapy. Further therapy options are considered after conventional procedures have been exhausted. These further options consist of improvement of the blood supply by surgical or minimally invasive procedures. The latter therapy options include balloon dilatation and stenting as the most widely used techniques. More recent techniques also used are cryoplasty, laser angioplasty, drug-coated stents or balloons as well as brachytherapy or atherectomy, whereby this list makes no claims to completeness. The multitude of different treatment methods emphatically underlines the fact that no resounding success can be achieved with one single method. The long-term results of both balloon dilatation and stenting techniques show a need for improvement, which elicited the search for additional methods for the treatment of PAOD. Atherectomy represents such an alternative method for treatment of PAOD. Basically, the term atherectomy means the removal of atheroma tissue. For percutaneous atherectomy, in contrast to surgical procedures, it is not necessary to create surgically access to the vessel but accomplishes the atherectomy by means of dedicated systems via a minimally invasive access. There are two basic forms of mechanical atherectomy: directional and rotational systems.

A wire transposition technique for recanalization of chronic complex central venous occlusions

Purpose A minimal-invasive interventional technique for recanalization of complex chronic central venous total occlusions is described to overcome difficulties in case of failure of common approaches. Method We present a patient with a central venous occlusion that caused severe venous congestion of her upper extremity and significant impairment of her forearm hemodialysis shunt. Since the usual transbrachial and transfemoral attempts for recanalization of occluded right subclavian, brachiocephalic, superior vena cava, and proximal internal jugular veins (IJV) failed, the approach was changed to a transjugular access. Only the IJV and subclavian vein occlusions were passed from transjugular. Results The key procedure was the switch of a jugular-brachial wire to a femoral-brachial setting. The wire transposition was achieved by snaring the looped stiff end of the jugular-brachial wire outside the jugular sheath from the opposite femoral access. Conclusion Different approaches should be considered for the recanalization of challenging central venous occlusions. After failed attempts via common access sites, a guidewire transposition maneuver using a combined approach may be particularly helpful for safe and effective endovascular treatment of complex situations.