[Complicated acute type B aortic dissection-what does endovascular therapy contribute?] / Akute komplizierte Typ-B-Dissektion ­ was leistet die endovaskuläre Therapie?

BACKGROUND: Acute aortic dissection type B is a severe and life-threatening vascular emergency. Complications such as rupture and/or malperfusion of organs are the main reasons for early mortality. OBJECTIVES: The aim is to provide an overview on important diagnostic radiological findings, conservative as well as endovascular therapeutic options for patients presenting with rupture or malperfusion syndromes. RESULTS: Medical treatment consisting of blood pressure and heart rate control as well las adequate analgesia remains the cornerstone therapy of all type B aortic dissections. In case of organ malperfusion, various endovascular therapies, e. g., endoluminal fenestration of dissection flap, thoracic stent-graft implantation (TEVAR) or branch vessel stenting, are available. In the case of aortic rupture, TEVAR has become the standard owing to its lower mortality compared to open surgical repair. DISCUSSION: For the treatment of complicated type B aortic dissection, a number of endovascular options are available. For optimal treatment, profound knowledge of the disease, of the diagnostic workup, and of the interventional procedures is mandatory.

Mid-term Results of Chimney and Periscope Grafts in Supra-aortic Branches in High Risk Patients.

PURPOSE: Report mid-term outcomes of thoracic endovascular aneurysm repair (TEVAR) with chimney and periscope grafts (CPG) in supra-aortic branches (SAB). METHODS: Retrospective analysis, from October 2009 to May 2014, of patients with aneurysms requiring TEVAR with zone 0/1/2 proximal landing in association with at least one CPG in the SAB. All patients were considered at high risk for conventional surgery. Peri-operative mortality and morbidity, retrograde type A dissection, maximum aortic transverse diameter (TD) and its post-operative evolution, endoleak, survival, freedom from cardiovascular re-interventions, and CPG freedom from occlusion during the follow-up were analysed. RESULTS: Forty-one patients (28.05% EuroScore II) with thoraco-abdominal aortic aneurysm (17%), arch aneurysm (39%), descending aneurysm (34%), and aneurysm extending from the arch to the visceral aorta (10%) were included. Fifteen (37%) patients were treated non-electively. Fifty-nine SABs were treated with the CPG technique: one, two, three, and four CPG were employed in 71%, 19%, 5%, and 5% of patients, respectively. The proximal landing was in zone 0 in 49% of patients, zone 1 in 17%, and zone 2 in 34%. Technical success was 95%. Peri-operative complications and neurological events were registered in six (14.6%) patients and there were 5 deaths (12%). At a median follow-up of 21.2 (mean 22, SD 18; range 0-65) months, type I/III endoleaks were registered in three (7%) cases and re-intervention in six (15%) patients. A significant aneurysm sac shrinkage (p<.001) was reported at mean follow-up and no significant aneurysm sac increase (>5 mm). The estimated 2 year survival, freedom from re-intervention, freedom from endoleak, and freedom from branch occlusion were 75%, 77%, 86%, and 96%, respectively. CONCLUSION: The chimney and periscope grafts technique was shown to be safe in aortic aneurysm disease involving the supra aortic branches, even in an emergency setting using off the shelf devices. Mid-term follow-up results in this high risk population are good, but longer follow-up is mandatory before this technique is used in intermediate-risk patients.

Mid- and Longer-term Follow up of Chimney and/or Periscope Grafts and Risk Factors for Failure.

OBJECTIVE: The aim was to report on chimney and periscope grafts (CPGs) and their mid- and longer-term outcomes when they are used to preserve reno-visceral artery (RVA) perfusion in endovascular repair of pararenal (PRAAs) or thoraco-abdominal aortic aneurysm (TAAAs). In addition, factors associated with CPG failure are presented. Limited data exist on the outcomes of CPGs, and mid- and long-term results are generally not reported. METHODS: This was a prospective study in a cohort of 100 patients with PRAA (69) or TAAA (31). A total of 224 (mean 2.24 per patient) RVAs were preserved with 136 (61%) chimney and 88 (39%) periscope grafts. CPGs were constructed mainly using self expandable stent grafts. Patients were followed by clinical examination, CTA (82%), and/or duplex (18%). Data were collected until February 2015. RESULTS: CPG immediate technical success was 99% (222/224 branches). Mean follow up was 29 months (range 0-65; SD 17); 59% patients were followed > 2 years, 30% > 3 years, and 16% > 4 years. Post-operatively, CPG occlusion was observed early (≤30 days) in three (1.3%) branches and during follow up in 10 (4.5%). At 36 and 48 months, the estimated primary patency was 93% and 93%. After corrective percutaneous (10) or surgical (3) re-interventions, the estimated secondary patency was 96% and 96%. Thirty day mortality was 2%; at 36 and 48 months the estimated patient survival was 79%. Significant shrinkage (72 [SD 23] vs. 62 [SD 24] mm; p < .001) was observed, with a substantial reduction (>5 mm) in 55 patients, and sac enlargement in four. Incomplete aneurysm sac sealing was treated successfully by a secondary intervention in 15 patients. CONCLUSIONS: Self expandable CPGs have proved to be a highly successful and durable treatment for RVA preservation up to 5 years. Incomplete CPG expansion, inadequate length, and CPG use in small and diseased target arteries were risk factors for occlusion. These mid- and longer-term results support CPG use to treat PRAAs or TAAAs in patients unfit for open surgery or fenestrated/branched stent grafts.

Diagnostic performance of 18F-FDG-PET/CT in vascular graft infections.

OBJECTIVE: The aim of this study was to evaluate the diagnostic accuracy of positron emission tomography/computed tomography with (18)F-fludeoxyglucose (FDG-PET/CT) in a population with suspected graft infection and to validate a new diagnostic imaging score for FDG-PET/CT. METHODS: This was a prospective cohort study. FDG-PET/CT was performed prospectively in 34 patients with suspected graft infection, in 12 of them before the start of antimicrobial treatment. Diagnostic accuracy was assessed using a new five point visual grading score and by using a binary score. Maximum standardized uptake values (SUVmax) were calculated for quantitative measurements of metabolic activity, and cut off points were calculated using the receiver operator curve (ROC). The standard of reference was a microbiological culture, obtained after open biopsy or graft explantation. RESULTS: Using the new scale, FDG-PET/CT correctly recognized 27 patients with graft infection, one patient was diagnosed as false positive, six patients were correctly classified as true negative, and no patients were rated false negative. Hence, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FDG-PET/CT for the diagnosis of graft infections were 100%, 86%, 96%, 100%, and 97%, respectively. Using a previously established binary score, sensitivity, specificity, PPV, NPV, and accuracy were 96%, 86%, 96%, 86%, and 94% respectively. ROC analysis suggested an SUVmax cut off value of ≥3.8 to differentiate between infected and non-infected grafts (p < .001). Additionally, FDG-PET/CT provided a conclusive clinical diagnosis in six of seven patients without graft infection (i.e., other sites of infections). CONCLUSIONS: The diagnostic accuracy of FDG-PET/CT in the detection of aortic graft infection is high. A newly introduced five point visual grading score and early imaging prior to antimicrobial treatment may further improve the diagnostic accuracy.

Model-based iterative reconstruction for improvement of low-contrast detectability in liver CT at reduced radiation dose: ex-vivo experience.

AIM: To compare low-contrast detectability, and qualitative and quantitative image parameters on standard and reduced radiation dose abdominal CT reconstructed with filtered back projection (FBP) and model-based iterative reconstruction (MBIR). MATERIALS AND METHODS: A custom built liver phantom containing 43 lesions was imaged at 120 kVp and four radiation dose levels (100% = 188 mAs, 50%, 25%, and 10%). Image noise and contrast-to-noise ratios (CNR) were assessed. Lesion detection and qualitative image analysis (five-point Likert scale with 1 = worst, 5 = best for confidence) was performed by three independent radiologists. RESULTS: CNR on MBIR images was significantly higher (mean 246%, range 151-383%) and image noise was significantly lower (69%, 59-78%) than on FBP images at the same radiation dose (both p < 0.05). On MBIR 10% images, CNR (3.3 ± 0.3) was significantly higher and noise (15 ± 1HU) significantly lower than on FBP 100% images (2.5 ± 0.1; 21 ± 1 HU). On 100% images, lesion attenuation was significantly lower with MBIR than with FBP (mean difference -2 HU). Low-contrast detectability and qualitative results were similar with MBIR 50% and FBP 100%. CONCLUSION: Low-contrast detectability with MBIR 50% and FBP 100% were equal. Quantitative parameters on even lower dose MBIR images are superior to 100%-dose FBP images. Some attenuation values differ significantly with MBIR compared with FBP.