Iatrogenic iliac artery rupture and type a dissection after endovascular repair of type B aortic dissection

We report a case of two iatrogenic complications after endovascular repair of a type B aortic dissection treated for abdominal aortic branch ischemia. A rupture of the common iliac artery occurred first during the procedure. A type A dissection occurred 12 days later. The proximal part of the aortic endovascular graft had created a tear in the aortic wall resulting in a retrograde type A dissection. Although aortic endovascular grafting is apparently associated with less morbidity and mortality, potentially lethal complications, both acute and delayed, may arise.     

Laparoscopic surgery for benign lesions of the pancreas

Background: Minimally invasive pancreatic surgery, although known to be feasible and safe, is still not considered a standard procedure. We report our experience with laparoscopic pancreatic surgery in a retrospective case series. Materials and Methods: Fifteen consecutive patients (3 male, 12 female) underwent primarily laparoscopic pancreatic surgery from February 2000 to June 2005. Histologically confirmed diagnoses were: neuroendocrine pancreatic tumors (n = 11), adult nesidioblastosis (n = 1), serous cystadenoma (n = 1), and pseudocysts due to chronic pancreatitis (n = 2). Results: Enucleation (n = 3) or left pancreatic resection with spleen preservation (n = 6) was performed laparoscopically in 9 patients. The mean (+/-standard deviation) operative time was 173 +/- 48 minutes (range, 120-250 minutes) and the mean postoperative hospital stay was 5.5 +/- 1.2 days (range, 5-8 days) for the laparoscopic cases. Conversion to open surgery was necessary in 6 patients because of: closeness of the lesion to the portal/mesenteric vein (n = 3), inadequate intraoperative tumor localization (n = 2), or stapler device dysfunction (n = 1). In these patients, open enucleation (n = 1), middle segment pancreatectomy (n = 2), left pancreatic resection (n = 2), and pylorus-preserving Whipple resection (n = 1) were performed. The mean operative time was 268 +/- 74 minutes (range, 150-360 minutes) with a mean postoperative hospital stay of 8 +/- 2 days (range, 6-10 days). Both operative time and hospital stay were significantly longer in patients with secondary open surgery compared to patients with successful laparoscopic operations. Conclusion: Laparoscopic enucleation or distal pancreatectomy with spleen preservation for benign lesions located in the body or tail of the pancreas can be performed safely, with all the potential benefits of minimally invasive surgery. Preoperative tumor localization is of utmost importance to limit pancreatic mobilization and to avoid blind pancreatic resection and conversion to open surgery.     

Threshold-based prediction of the coagulation zone in sequential temperature mapping in MR-guided radiofrequency ablation of liver tumours

Objective

To evaluate different cut-off temperature levels for a threshold-based prediction of the coagulation zone in magnetic resonance (MR)-guided radiofrequency (RF) ablation of liver tumours.

Methods

Temperature-sensitive measurements were acquired during RF ablation of 24 patients with primary (6) and secondary liver lesions (18) using a wide-bore 1.5?T MR sytem and compared with the post-interventional coagulation zone. Temperature measurements using the proton resonance frequency shift method were performed directly subsequent to energy application. The temperature maps were registered on the contrast-enhanced follow-up MR images acquired 4?weeks after treatment. Areas with temperatures above 50°, 55° and 60°C were segmented and compared with the coagulation zones. Sensitivity and positive predictive value were calculated.

Results

No major complications occurred and all tumours were completely treated. No tumour recurrence was observed at the follow-up examination after 4?weeks. Two patients with secondary liver lesions showed local tumour recurrence after 4 and 7?months. The 60°C threshold level achieved the highest positive predictive value (87.7?±?9.9) and the best prediction of the coagulation zone.

Conclusions

For a threshold-based prediction of the coagulation zone, the 60°C cut-off level achieved the best prediction of the coagulation zone among the tested levels.

Key Points

? Temperature monitoring can be used to survey MR-guided radiofrequency ablation ? The developing ablation zone can be estimated based on post-interventional temperature measurements ? A 60°C threshold level can be used to predict the ablation zone ? The 50°C and 55°C temperature zones tend to overestimate the ablation zone     

Noninvasive coronary angiography with 16-detector row CT: effect of heart rate

PURPOSE: To evaluate the effect of heart rate on the quality of coronary angiograms obtained with 16-detector row computed tomography (CT) by using temporally enhanced three-dimensional (3D) approaches. MATERIALS AND METHODS: The local ethics committee approved the study, and informed consent was obtained from all patients. Fifty patients underwent coronary CT angiography (heart rate range, 45-103 beats per minute). Raw data from helical CT and electrocardiography (ECG) were saved in a combined data set. Retrospectively ECG-gated images were reconstructed at preselected phases (50% and 80%) of the cardiac cycle. A 3D voxel-based approach with cardiac phase weighting was used for reconstruction. Testing for correlation between heart rate, cardiac phase reconstruction window, and image quality was performed with Kruskal-Wallis analysis. Image quality (freedom from cardiac motion-related artifacts) was referenced against findings at conventional angiography in a secondary evaluation step. Regression analysis was performed to calculate heart rate thresholds for future beta-blocker application. RESULTS: A significant negative correlation was observed between heart rate and image quality (r = 0.80, P < .001). Motion artifact-free images were available for 44 (88%) patients and were achieved consistently at a heart rate of 80 or fewer beats per minute (n = 39). Best image quality was achieved at 75 or fewer beats per minute. Segmental analysis revealed that 97% of arterial segments (diameter > or = 1.5 mm according to conventional angiography) were assessable at 80 or fewer beats per minute. Premature ventricular contractions and rate-contained arrhythmia did not impede diagnostic assessment of the coronary arteries in 10 (83%) of the 12 patients affected. CONCLUSION: Motion-free coronary angiograms can be obtained consistently with 16-detector row CT scanners and adaptive multicyclic reconstruction algorithms in patients with heart rates of less than 80 beats per minute.     

PET-based human dosimetry of 18F-galacto-RGD, a new radiotracer for imaging alpha v beta3 expression.

(18)F-Galacto-RGD is a new tracer for PET imaging of alpha v beta3, a receptor involved in a variety of pathologic processes including angiogenesis and metastasis. Our aim was to study the dosimetry of (18)F-galacto-RGD in humans. METHODS: Eighteen patients with various tumors (musculoskeletal tumors [n = 10], melanoma [n = 5], breast cancer [n = 2], or head and neck cancer [n = 1]) were examined. After injection of 133-200 MBq of (18)F-galacto-RGD, 3 consecutive emission scans from the thorax to the pelvis were acquired at 6.7 +/- 2.9, 35.6 +/- 7.6, and 70.4 +/- 12.2 min after injection. Blood samples (n = 4) for metabolite analysis were taken 10, 30, and 120 min after injection. The OLINDA 1.0 program was used to estimate the absorbed radiation dose. RESULTS: Reversed-phase high-performance liquid chromatography of serum revealed that more than 95% of tracer was intact up to 120 min after injection. (18)F-Galacto-RGD showed rapid clearance from the blood pool and primarily renal excretion. Background activity in lung and muscle tissue was low (percentage injected dose per liter at 71 min after injection, 0.56 +/- 0.15 and 0.69 +/- 0.25, respectively). The calculated effective dose was 18.7 +/- 2.4 microSv/MBq, and the highest absorbed radiation dose was in the bladder wall (0.22 +/- 0.03 mGy/MBq). CONCLUSION: (18)F-Galacto-RGD demonstrates high metabolic stability, a favorable biodistribution, and a low radiation dose. Consequently, this tracer can safely be used for noninvasive imaging of molecular processes involving the alpha v beta3 integrin and for the planning and monitoring of therapeutic approaches targeting alpha v beta3.     

VerstÄrkung der radiotherapeutischen wirkung auf HeLa-Zellen durch gemcitabine

BACKGROUND: Gemcitabine (2'.2'-difluorodeoxycytidine; dFdC) is a new nucleoside analog with promising activity in different solid tumors in vivo and in vitro. As published up to now, combined with irradiation dFdC demonstrates a radiosensitizing effect on pancreas and colon carcinoma cell lines. We investigated the influence of dFdC on the radiosensitization of human squamous carcinoma cells of the cervix (HeLa-cells, ATCC CCL-2). MATERIAL AND METHODS: Under standardized conditions monolayer cultures of HeLa-cells were incubated in medium with dFdC for different times (4 to 24 hours) and exposed to different concentrations (0.003, 0.01 and 0.03 mumol/l). Irradiation (2 to 6 Gy, electron beam) followed immediately or 12 hours after dFdC-exposure. Cell survival was determined by colony forming assay. Using the linear-quadratic model cell survival curves were fit after correction for drug-induced cytotoxicity and the mean inactivation dose (MID) was calculated. Radiation enhancement was defined as the ratio MIDRT(= Control)/MIDRT + dFdC > 1. RESULTS: Exposed to gemcitabine for 4 and 8 hours and followed by immediate irradiation the radiation enhancement ratio (Table 1) is 1.07 to 1.14 and 1.04 to 1.22, respectively, if dFdC concentration is > or = 0.01 to 0.03 mumol/l. Further increase of the irradiation effect is demonstrated in cells exposed to > or = 0.003 to 0.03 mumol/l dFdC for 16 and 24 hours (radiation enhancement ratio 1.08 to 2.0 and 1.08 to 2.48, respectively) (Figure 3). If irradiation is applied 12 hours after 24-hour-exposure (0.01 and 0.03 mumol/l) the enhancement ratio was 1.18 and 1.7, respectively (Figure 4). CONCLUSIONS: In cell cultures the assays combining irradiation with dFdC demonstrate that dFdC is a potent radiation sensitizer of HeLa-cells. The effect of irradiation on cells pre-treated with non- and hardly cytotoxic concentrations of dFdC is increased in dependence of dose and time of exposure.     

German Association of Endocrine Surgeons practice guideline for the surgical management of malignant thyroid tumors

Introduction

Over the past years, the incidence of thyroid cancer has surged not only in Germany but also in other countries of the Western hemisphere. This surge was first and foremost due to an increase of prognostically favorable (“low risk”) papillary thyroid microcarcinomas, for which limited surgical procedures are often sufficient without loss of oncological benefit. These developments called for an update of the previous practice guideline to detail the surgical treatment options that are available for the various disease entities and tumor stages.

Methods

The present German Association of Endocrine Surgeons practice guideline was developed on the basis of clinical evidence considering current national and international treatment recommendations through a formal expert consensus process in collaboration with the German Societies of General and Visceral Surgery, Endocrinology, Nuclear Medicine, Pathology, Radiooncology, Oncological Hematology, and a German thyroid cancer patient support organization.

Results

The practice guideline for the surgical management of malignant thyroid tumors includes recommendations regarding preoperative workup; classification of locoregional nodes and terminology of surgical procedures; frequency, clinical, and histopathological features of occult and clinically apparent papillary, follicular, poorly differentiated, undifferentiated, and sporadic and hereditary medullary thyroid cancers, thyroid lymphoma and thyroid metastases from primaries outside the thyroid gland; extent of thyroidectomy; extent of lymph node dissection; aerodigestive tract resection; postoperative follow-up and surgery for recurrence and distant metastases.

Conclusion

These evidence-based recommendations for surgical therapy reflect various “treatment corridors” that are best discussed within multidisciplinary teams and the patient considering tumor type, stage, progression, and inherent surgical risk.     

Thoracic aortic stent-graft devices: problems, failure modes, and applicability

Optimal treatment strategies for pathologies of the descending thoracic aorta are still controversial. Open surgery is complex, while endovascular devices allow nonsurgical access to the thoracic aorta. Endografts can be inserted via a peripheral artery while maintaining aortic blood flow without any need for clamping. Both short- and mid-term outcomes after endografting thoracic aneurysm and type B aortic dissection are encouraging, with significantly lower morbidity and early mortality compared with open surgery. However, despite emerging popularity and growing interest as an alternative to surgery, endograft design and manufacturing have not kept pace with growing clinical ambition. Major challenges associated with endovascular procedures using the current generation of endografts range from the relative rigidity and size of the delivery system to the failure of thoracic endografts to conform snugly to the anatomy of the aortic arch. Nonconformity of grafts may lead to graft instability, endoleak, and procedural failure. Current delivery systems are potentially traumatizing and, at times, too inflexible to track through tortuous, calcified vessels, and often require surgical exposure of the access vessel. Although efforts have been made by the industry to improve conformability and fixation in the aortic arch, given the spiraling movement of the thoracic aorta with each ventricular contraction, much work needs to be done on miniaturization and creation of disease-specific devices. The aim of this work is to give an overview on thoracic aortic stent-graft devices with focus on problems, failure modes and potential improvements.     

Ultrasonic sensor concept to fit a ventricular assist device cannula evaluated using geometrically accurate heart phantoms

Future left ventricular assist devices (LVADs) are expected to respond to the physiologic need of patients; however, they still lack reliable pressure or volume sensors for feedback control. In the clinic, echocardiography systems are routinely used to measure left ventricular (LV) volume. Until now, echocardiography in this form was never integrated in LVADs due to its computational complexity. The aim of this study was to demonstrate the applicability of a simplified ultrasonic sensor to fit an LVAD cannula and to show the achievable accuracy in vitro. Our approach requires only two ultrasonic transducers because we estimated the LV volume with the LV end‐diastolic diameter commonly used in clinical assessments. In order to optimize the accuracy, we assessed the optimal design parameters considering over 50 orientations of the two ultrasonic transducers. A test bench was equipped with five talcum‐infused silicone heart phantoms, in which the intra‐ventricular surface replicated papillary muscles and trabeculae carnae. The end‐diastolic LV filling volumes of the five heart phantoms ranged from 180 to 480 mL. This reference volume was altered by ±40 mL with a syringe pump. Based on the calibrated measurements acquired by the two ultrasonic transducers, the LV volume was estimated well. However, the accuracies obtained are strongly dependent on the choice of the design parameters. Orientations toward the septum perform better, as they interfere less with the papillary muscles. The optimized design is valid for all hearts. Considering this, the Bland‐Altman analysis reports the LV volume accuracy as a bias of ±10% and limits of agreement of 0%–40% in all but the smallest heart. The simplicity of traditional echocardiography systems was reduced by two orders of magnitude in technical complexity, while achieving a comparable accuracy to 2D echocardiography requiring a calibration of absolute volume only. Hence, our approach exploits the established benefits of echocardiography and makes them applicable as an LV volume sensor for LVADs.     

Risk of wound hematoma at carotid endarterectomy under dual antiplatelet therapy

Background and purpose

This study aims to assess perioperative incidence of wound hematoma and bleeding in patients who underwent carotid endarterectomy (CEA) under dual antiplatelet therapy.

Methods

Consecutive patients with initial CEA receiving aspirin, clopidogrel, or a combination of both were subjected to standard patch endarterectomy. Postoperative wound hematoma was assessed as moderate (subcutaneous bleeding, nonspace-occupying hematoma, and oozing suture bleeding) or severe, i.e., needing operative re-exploration.

Results

Six hundred eighty-four (80.9?%) patients with one of the three types of antiplatelet therapy out of 844 patients registered from 1995 to 2010 were enrolled. Wound hematoma occurred in 27 of 112 (24.1?%) patients under combined aspirin and clopidogrel, 33 of 162 (20.4?%) under clopidogrel, and 48 of 410 (11.7?%) under aspirin. Relative risk compared to aspirin was 2.4 (95?% CI, 1.4 to 4.1) for aspirin and clopidogrel and 1.9 (95?% CI, 1.2 to 3.1) for clopidogrel. Severe space-occupying hematoma needing operative re-exploration occurred in four (3.6?%) patients under aspirin and clopidogrel, seven (4.3?%) under clopidogrel, and five (1.2?%) under aspirin. Corresponding relative risks were 3.0 (95?% CI, 0.8 to 11.4) for aspirin and clopidogrel and 3.7 (95?% CI, 1.1 to 11.7) for clopidogrel. Relative risks remained without relevant change after adjustment for potentially confounding variables.

Conclusions

Dual antiplatelet therapy with combined aspirin and clopidogrel as well as clopidogrel is associated with an increased incidence of perioperative wound hematoma compared to aspirin but on an acceptable low level of incidence. The latter may be achieved by adapting operative procedures to more intensive antiplatelet regimes.