[Influence of fixation mechanism on changes of the supra- and infrarenal segment of the aorta after endovascular treatment of infrarenal aortic aneurysm]. / Einfluss des Verankerungsmechanismus auf Veränderungen des supra- und infrarenalen Aortensegments nach endovaskulärer Ausschaltung infrarenaler Bauchaortenaneurysmen.

INTRODUCTION: Dilatation of the infrarenal aortic segment determines the long-term outcome after endovascular repair of abdominal aortic aneurysms. This segment is crucial for sealing and preventing stent-graft migration. The purpose of this study was to evaluate influence of fixation mechanism on changes of supra- and infrarenal aortic diameters over a 10-year period. METHODS: We reviewed all our endovascular procedures for abdominal aortic aneurysms and follow-up CT scans between 1998 and 2008. Only patients with the three most frequently implanted self-expandable stent-graft types and a minimal follow-up of three months were included in this study. Further inclusion criteria were elective repair and follow-up at our department to consistent data formats. A total of 103 patients, 35 with suprarenal fixation without hooks (Medtronic Talent®, Medtronic World Medical, Sunrise, FL, USA), 29 with suprarenal fixation with hooks (Cook Zenith®, Cook Inc. Bloomington, IN, USA) and 39 with infrarenal fixation with anchors (Gore Excluder®, W. L. Gore & Associates, Flagstaff, Ariz, USA) met the inclusion criteria. All measurements were performed in duplicate by two different investigators to determine intra- and interobserver errors. Based on this error a minimal change of 2 mm of infrarenal aortic neck diameter was determined as aortic neck dilatation. RESULTS: During a mean follow-up time of 39.4 (3-108.8) months, infrarenal aortic neck dilatation was found in 28.57% in the Medtronic group, 10.26% in the Gore group and 31.03 in the Cook group. Suprarenal changes were 17.14%, 20.51% and 17.24%, respectively. Reduction of the maximal diameter could be achieved in 74.3% (Medtronic), 79.5% (Gore), and 75.8% (Cook). Seven of 23 patients with a notable dilatation of the infrarenal neck required reintervention. All of them were stent-grafts with suprarenal fixation. No statistical significance was found between the 3 groups regarding changes of suprarenal or infrarenal diameters or migration rates. CONCLUSION: Although no statistical significance was found among the groups, infrarenal fixation showed the lowest rate of infrarenal dilatation.

Regulation of endothelial nitric oxide synthase (eNOS) in myocardium subjected to cardioplegic arrest.

BACKGROUND: Nitric oxide (NO) production by both coronary endothelial cells and cardiomyocytes is thought to play a significant role in myocardial pathophysiology following ischemia/reperfusion (I/R). METHODS: In thirteen pigs subjected to 1 hour cardioplegic arrest (CA) on CPB, left ventricular (LV) biopsies were collected prior to CPB (baseline), at 60 min CPA, at 15 and 30 min reperfusion on CPB, and at 120 min post CPB. LV specimens were immunocytochemically stained against phospho-eNOS (Ser1177), phospho-eNOS (Thr495), phosphorylated ERK1/2, and AKT/PKB. Four additional pigs without CA served as controls. Cardiomyocytes were quantitatively investigated using TV densitometry (gray units: U). RESULTS: After 60 min CA phosphorylation of eNOS (Ser1177) increased significantly and remained elevated until 30 min of reperfusion. In contrast, eNOS (Thr495) phosphorylation remained unchanged during CA and throughout reperfusion. In control animals, eNOS phosphorylation remained unchanged. Akt/PKB activity significantly increased after 60 min CA and decreased thereafter. ERK1/2 activity remained unchanged during ischemia but increased during reperfusion. CONCLUSIONS: ENOS activation during ischemia occurs through phosphorylation at Ser1177 mediated by Akt/PKB. ERK1/2 does not seem to be involved in myocardial eNOS regulation especially not via phosphorylation at eNOS (Thr495).

Pitfalls in detection of acute gastrointestinal bleeding with multi-detector row helical CT.

Contrast-enhanced multi-detector row helical CT angiography is establishing itself as an accurate, rapid, and non-invasive diagnostic modality in patients with acute gastrointestinal bleeding. On arterial phase MDCT images ongoing hemorrhage can be revealed as an area of active extravasation of contrast material within the bowel lumen. This pictorial essay gives a short overview of current diagnostic modalities in assessing acute GI tract bleeding, typical MDCT findings, and depicts potential pitfalls in the detection of acute GI bleeding with MDCT.

Evaluation of accordance of magnetic resonance volumetric and flow measurements in determining ventricular stroke volume in cardiac patients.

BACKGROUND: Cardiovascular magnetic resonance imaging (CMR) has become an established noninvasive method for evaluating ventricular function utilizing three-dimensional volumetry. Postprocessing of volumetric measurements is still tedious and time consuming. Stroke volumes obtained by flow quantification across the aortic root or pulmonary trunk could be utilized to increase both speed of workflow and accuracy. PURPOSE: To assess accuracy of stroke volume quantification using MR volumetric imaging compared to flow quantification in patients with various cardiac diseases. Strategies for the augmentation of accuracy in clinical routine were deduced. MATERIAL AND METHODS: 78 patients with various cardiac diseases-excluding intra- or extracardiac shunts, regurgitant valvular defects, or heart rhythm disturbance-underwent cardiac function analysis with flow measurements across the aortic root and cine imaging of the left ventricle. Forty-six patients additionally underwent flow measurements in the pulmonary trunk and cine imaging of the right ventricle. RESULTS: Left ventricular stroke volume (LVSV) and stroke volume of the aortic root (SVAo) correlated with r=0.97, and Bland-Altman analysis showed a mean difference of 0.11 ml and a standard error of estimation (SEE) of 4.31 ml. Ninety-two percent of the data were within the 95% limits of agreement. Right ventricular stroke volume (RVSV) and stroke volume of the pulmonary trunk (SVP) correlated with a factor of r=0.86, and mean difference in the Bland-Altman analysis was fixed at -2.62 ml (SEE 8.47 ml). For RVSV and SVP, we calculated r=0.82, and Bland-Altman analysis revealed a mean difference of 1.27 ml (SEE 9.89 ml). LVSV and RVSV correlated closely, with r=0.91 and a mean difference of 2.79 ml (SEE 7.17 ml). SVAo and SVP correlated with r=0.95 and a mean difference of 0.50 ml (SEE 5.56 ml). CONCLUSION: Flow quantification can be used as a guidance tool, providing accurate and reproducible stroke volumes of both ventricles. Combining both offers a highly accurate tool to gauge ventricular function in a routine clinical setting, increasing workflow speed.

Impact of hematocrit value after coronary artery surgery on perioperative myocardial infarction rate.

BACKGROUND: The optimal hematocrit (HCT) value after coronary artery bypass grafting on cardiopulmonary bypass (CPB) has not yet been established. The purpose of our retrospective study was to investigate the association between HCr at the time of entry into the ICU and perioperative Ml rate. METHODS: We reviewed the charts of 500 consecutive coronary artery surgery patients with respect to biometric data, operative procedure, aprotinin or tranexamic acid use, perioperative drainage blood loss and transfusion requirements, perioperative Ml, ICU stay and hospital mortality. Perioperative Ml was defined as new Q-wave on ECG and CK-MB 250U/I. Patients were categorized into three groups depending on their HCr value at the time of entry into the ICU: low (HCTcu 27%): medium (HCr,cu 28% to 32%); high(HCTrcu > or =33%). RESULTS: Age, gender distribution, preoperative LV function, and previous Ml rate were similar between the three groups. Low HCT patients (n -133) received 3.1 +/- 1.0 (Mean + SD) grafts during 55 +/- 19 minutes aortic cross clamp time, 98 +/- 31 minutes on CPB (medium HCT: n = 257; 3.2 +/- 1.0 grafts, 51 +/- 20 min cross clamp time, 93 +/- 30 min CPB; p - 0.45 vs. low HCT; high HCT: n = 110: 3.3 +/- 1:0 grafts; 53 +/- 20 min cross clamp time; 104 +/- 38 min CPB; p = 0.02 vs. medium HCT). The perioperative Ml rate was 3.8% in the low, 4.3% in the medium, and 6.4% in the high-HCr group (p =0.59 ). Intraoperative red blood cell and fresh frozen plasma transfusions were similar between the groups. In the low-HCa group, 53.4% of the patients received aprotinin during the procedure (medium HCa: 65.4%; high HCT: 77.3%; p<0.001). Drainage blood loss during the first 24 hours on ICU was 834 +/- 453 ml in the low, 757 +/- 485 ml in the medium (p -0.44 vs. low), and 640 +/- 353 ml in the high-HCr group (p = 0.003 vs. low). Postoperative red blood cell and fresh frozen plasma transfusions were highest in the low-HCa group(p<0.001). ICU stay was similar between the groups. Hospital mortality was 0.75% in the low, 1.9% in the medium, and 4.5%in the high-HCa group (p = 0.12). CONCLUSIONS: In this retrospective analysis of 500 consecutive coronary artery surgery patients, we did not find any association between perioperative Ml rate and HCr value on entry into the ICU. These results do not support the recent suggestion that low HCT at the time of entry into the ICU protects against perioperative Ml.

[Detection of air embolism by a re-usable Doppler probe integrated in a central venous line--application in-vivo]. / Wiederverwendbare, in einen Zentralvenenkatheter integrierbare Dopplersonde zur Detektion von Luftembolien Anwendung in-vivo.

PROBLEM: Air embolism frequently occurs under neurosurgical operations performed in the sitting position. Recently we reported the idea of inserting a re-usable doppler probe into a blind-ending lumen of a central venous catheter (Schregel-Volk-Catheter, SVC). In vitro testing in a circulation model showed a high sensitivity: air bubbles as small as 0.5 microliter were reliably detected at a distance up to 4 cm from the tip of the SVC. METHOD: After approval by the local ethics committee pigs were anaesthetised and a cardiopulmonary bypass was connected. During the bypass period a 12 F SVC (Medex Medical, Germany) with one blind-ending lumen was positioned into the proximal vena cava cranialis or vena cava caudalis. An 8 MHz doppler probe (MTB Basler, Suisse) was introduced into the SVC and connected with the doppler device Multi-Dop T (DWL, Germany). Well defined air bubbles (3-6 microliter) were generated by a bubble generator and injected into the right femoral vein or the left vena jugularis interna. RESULTS: All bubbles were reliably detected by the re-usable doppler probe. Embolic events can be documented, counted and quantified by the Multi-Dop T. CONCLUSION: Using SVC's with a blind-ending lumen could improve and simplify the detection of air embolism. We see several advantages (e.g. sensitivity, costs) compared with established methods (precordial doppler, TEE) for detection of air embolism.