[Show abstract][Hide abstract] ABSTRACT: This study aims to evaluate the value of VEGF as a surrogate marker for peripheral vascular disease (PVD). Prior to treatment, serum VEGF levels were evaluated by enzyme-linked immunosorbent assay (ELISA) in 293 PVD patients. Risk factors and clinical parameters of PVD were documented. Twenty-six age-matched healthy volunteers served as controls. Serum VEGF values strongly correlated with Fontaine stages (p<0.006, stage IV vs. controls). High VEGF values prior to treatment were associated with poor outcome. Serum VEGF appears to indicate the severity of PVD and might serve as a surrogate indicator of disease severity.
Full-text · Article · Nov 2009 · European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery
[Show abstract][Hide abstract] ABSTRACT: Evaluamos el pronóstico clínico a largo plazo de 33 pacientes tratados para un traumatismo arterial de la extremidad superior en el Regensburg University Medical Center entre 1996 y 2004. Durante el seguimiento, junto a los parámetros clínicos, de cada paciente se obtuvo la puntuación en la escala Disabilities of Arm, Shoulder, and Hand (DASH) al igual que la puntuación del cuestionario Short Form-36 Health Survey (SF-36). Los hallazgos de la evaluación clínica se compararon con los resultados obtenidos en la puntuación de la DASH y en el cuestionario SF-36. El tiempo de seguimiento mediano fue de 42 meses. En el momento del seguimiento se habían reconstruido todas las lesiones arteriales y se mantenía la permeabilidad de los vasos. La prevalencia de lesiones nerviosas y/u ortopédicas concomitantes fue elevada (24/33, 72%). La influencia de una lesión nerviosa fue con diferencia mayor que las de otros factores en el pronóstico funcional a largo plazo. Además, un traumatismo contuso y la necesidad de una fasciotomía inmediata fueron marcadores adicionales de un restablecimiento funcional deficiente. Las puntuaciones obtenidas tanto en la DASH como en el SF-36 se correlacionaron con la evaluación clínica de la gravedad de los déficit funcionales. Un traumatismo vascular de la extremidad superior se asocia casi siempre con lesiones ortopédicas y/o nerviosas concomitantes. La afectación del plexo braquial y de los nervios periféricos de la extremidad superior es una variable predictora de un peor pronóstico funcional a largo plazo.
[Show abstract][Hide abstract] ABSTRACT: Endovascular therapy has been established as standard treatment for thoracic aortic disease. Endografts are increasingly being implanted in the aortic arch because more patients with aortic blunt trauma and dissection are being treated. However, placement of endografts in challenging aortic arches can lead to proximal endograft instability or endograft collapse, with fatal intestinal and peripheral malperfusion. The potential causes for endograft collapse were analysed based on a literature search and on our own experiences. A narrow aortic diameter and a short radius of the aortic arch (e.g. in patients with dissections or aortic blunt rupture) as well as oversizing and placement of the endograft in the distal arch are potential factors for endograft collapse. Device-related problems of the very flexible TAG endograft may also contribute, as can challenging anatomic situations. Strategies to avoid and detect endograft collapses are presented, and endovascular treatment solutions for this deleterious complication are offered.
[Show abstract][Hide abstract] ABSTRACT: Is Contrast Harmonic Imaging (CHI) comparable to computed tomography angiography (CTA) scan in detecting and characterizing suspected endoleaks after endovascular abdominal aneurysm repair in a non-selected group including reintervention procedure and branched endografts in daily practice?
In a prospective study computed tomography angiography (CTA) and contrast-enhanced ultrasound (CEUS) were performed in 30 consecutive patients (26 males, 4 females, mean age: 72 years, range: 38-87) with suspected endoleaks in follow-up (mean 13 months, range: 1-95) after endovascular abdominal aneurysm repair or procedure in dissection or penetrated ulcer of the aorta (25 infrarenal, 5 suprarenal stent grafts, mean aortic diameter 56 mm, range: 27-98). CTA was supposed to be gold standard for determining the presence of endoleaks (multislice CT, collimation 16 x 0.75 mm, 100 ml of iodized contrast agent bolus). Ultrasonography used a multi-frequency probe (1-4 MHz) with the modalities of colour coded Doppler sonography (CCDS), power Doppler (PD) combined with contrast enhancement and the technique of contrast harmonic imaging (CHI) and low mechanical index (MI < 0.2). 2.4 ml of SonoVue (Bracco, Altana Pharma GmbH, Italy) were administered to each patient intravenously as a bolus injection.
Out of 30 patients, 21 endoleaks were identified in CTA (6 type I or III, 15 type II), 22 in CHI. Thus, sensitivity for CHI was therefore 99%, its specificity 85% (Spearman correlation coefficient (CC) 0.92). In follow-up the localizations of endoleak type I or III exclusively detected by CHI were confirmed as true positive by angiography. Due to its dynamic characteristic CHI seemed to be more helpful in characterization of endoleaks than CTA. In case of a rupture after reintervention a type III endoleak leads to prompt intervention before receiving the result of the CT scan. Altogether, CHI failed to identify 1 combined type I and II endoleak (sensitivity 0.99). Both, CCDS and PD were positive only in 6/30 patients (CC 0.33 and 0.39). Interestingly the application of contrast agent doubles the detection rate of endoleaks (12/30) in CCDS and PD (CC 0.39).
Contrast harmonic imaging (CHI) compared to computed tomography angiography (CTA) accurately depicts endoleaks after endovascular abdominal aneurysm repair and stent-graft procedure in dissected and ulcerated aorta. It seems to be superior in characterization of the type of endoleaks and can be established in order to reduce iodized contrast agent and radiation exposure in follow-up. In contrast to CTA scan CHI can be offered to patients with chronic renal insufficiency and allows a dynamic examination and a perfusion analysis.
No preview · Article · Feb 2009 · Clinical hemorheology and microcirculation
[Show abstract][Hide abstract] ABSTRACT: Pre-surgical evaluation of the extent of internal carotid artery stenosis (ICA) according to NASCT criteria using digital 3D ultrasound methods.
In a prospective study, 25 patients (54-88 years, mean 75) with neurological deficits and the diagnosis of ICA stenosis underwent pre-surgical ultrasound examination using Color Coded Duplex Sonography (CCDS), 3D CCDS, 3D power Doppler, 3D B-flow, contrast enhanced 3D B-flow, and CTA/MRA. Ultrasound was performed by an experienced examiner with a multifrequency linear transducer (6-9 MHz, Logiq 9, GE). After bolus injection of 2.4 ml Sonovue i.v., low mechanical index technique (MI<0.16) was used for contrast enhanced 3D B-flow. As reference method for evaluation of the extent of ICA stenosis each patient underwent CTA (multislice CT, Sensation 16, Siemens) and/or MRA (1.5 T, Symphony Siemens). Indications for surgery (carotid EEA) followed the NASCET criteria. All images were interpreted and evaluated independently by two observers with three measurements of the degree of the ICA stenosis. For assessment of the extent of stenosis a 10%-scale from 50% to 99% was used. Statistical analysis was performed using Spearman Correlation and Wilcoxon Signed Rank Test with a significance threshold of p<0.05.
Assessment of the extent of ICA stenosis during surgery and in CTA/MRA displayed a range from 60% to 99% (mean 80%). Non significant differences were found with paired Wilcoxon test only for 3D B-flow with and without contrast medium (p<0.05). Correlation with surgical evaluation regarding the extent of ICA stenosis using Spearman correlation teat was 0.77 for B-scan, 0.90 for 3D CCDS, 0.84 for 3D Power Doppler, 0.91 for B-flow and 0.93 for contrast enhanced 3D B-flow. When circular calcifications were present, contrast enhanced flow detection of 3D B-flow proved to be useful. Visualisation of intrastenotic variances of severe and profound stenosis (70-99%) without blooming and reverberation artefacts was possible only with 3D B-flow. This facilitates the detection of the morphology of plaques ulcers as an embolic source.
In correlation with surgery and CTA/MRA, a valid evaluation of the extent and morphology of ICA stenosis using 3D B-flow, with and without contrast medium, is feasible.
No preview · Article · Jan 2009 · Clinical hemorheology and microcirculation
[Show abstract][Hide abstract] ABSTRACT: We assessed the long-term clinical outcome of 33 patients treated for arterial trauma of the upper extremity at the Regensburg University Medical Center between 1996 and 2004. Along with clinical parameters, the Disabilities of Arm, Shoulder, and Hand (DASH) score and the Short Form-36 Health Survey (SF-36) score of each patient were collected at the time of follow-up. Findings of the clinical assessment were compared to results obtained with the DASH score and the SF-36 questionnaire. The median follow-up time was 42 months. All arterial injuries had been reconstructed and were open at the time of follow-up. The prevalence of concomitant neural and/or orthopedic injuries was high (24/33, 72%). The influence of neural injury was by far greater than the impact of other factors on the long-term functional outcome. Furthermore, blunt trauma and the need for immediate fasciotomy were further markers for deficient functional recovery. Both the DASH and the SF-36 scores correlated with the clinical assessment of the severity of functional deficits. Upper extremity vascular trauma is almost always associated with severe concomitant orthopedic and/or neural injuries. The involvement of the brachial plexus and the peripheral nerves of the upper extremity is a predictor of worse long-term functional outcome.
No preview · Article · Sep 2008 · Annals of Vascular Surgery
[Show abstract][Hide abstract] ABSTRACT: The aim of this prospective randomized study was to demonstrate the comparability of retrojugular access for carotid eversion endarterectomy compared to the conventional ventrojugular procedure.
Due to the expected minor and major complication rate of 5% in patients undergoing carotid surgery, a patient cohort of 600 study patients was planned. All patients underwent standard preoperative and postoperative assessment including clinical investigation and fiberoptic laryngoscopy. The 6 month follow-up examination included an evaluation of patient contentment, a duplex scan, clinical investigation and a fiberoptic laryngoscopy.
After the first interim evaluation of 101 patients, the study was stopped because of a significant increase in temporary ipsilateral vocal cord motility dysfunction in the retrojugular access group (31% vs. 6%, p=0.0014). This early postoperative impairment was, however, not statistically significant at the follow-up examination at 6 months (2.4% vs. 0%). No other significant differences concerning major complications (death or stroke), other cranial nerve injuries, wound healing, or patient satisfaction was observed neither in the early postoperative phase nor at follow up.
Due to the high incidence of temporary ipsilateral vocal cord dysfunction in patients undergoing retrojugular exposure of the carotid artery, we recommend the conventional ventrojugular approach, which can be performed by incision along the anterior border of the sternomastoid muscle or by transversal skin incision.
Full-text · Article · Mar 2008 · European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery
[Show abstract][Hide abstract] ABSTRACT: Feasibility of intraarterial MR angiography of the renal arteries and comparison of the accuracy of intraarterial MR angiography with selective intraarterial digital subtraction angiography (DSA) for detection of stenoses.
Ten consecutive patients (mean, 68 years) with suspected renal artery stenosis underwent a digital subtraction angiography and an intraarterial gadolinium-enhanced MR angiography, performed on a 1.5-T system. For intraarterial MR angiography 60 ml diluted contrast agent (10 ml gadodiamide in 50 ml 0.9% saline solution) was injected through a conventional angiography catheter placed in the suprarenal abdominal aorta using a flow rate of 3.5 ml/s. A three-dimensional (3D) gradient-echo sequence was performed. Differences in the quantitative measurement of stenoses of lesions between DSA and intraarterial MR angiography were evaluated by three observers. Overall impression of the intraarterial MR angiography was documented on a four-point scale (1 = excellent to 4 = poor). Interobserver variability was calculated.
Intraarterial MR angiography of the renal arteries was feasible in all patients (100%) with a mean overall impression of all images of 1.8 (SD: 0.71). One of 9 accessory renal arteries was not visualized with intraarterial MR angiography. The overall sensitivity/specificity for detection of significant stenoses (>or=50% stenosis) were 83%/87%. Interobserver variability of intraarterial MR angiography ranged between fair and substantial (0.359-0.622).
Intraarterial MR angiography of the renal arteries in humans is feasible and has an acceptable sensitivity in detecting stenoses using injections of diluted contrast agent at concentrations as low as 17%.
No preview · Article · Jan 2008 · Clinical hemorheology and microcirculation
[Show abstract][Hide abstract] ABSTRACT: The aim of the prospective study was to evaluate the macro- and microcirculation in the center and periphery of free flaps with high resolution vascular ultrasound.
Fifteen patients with free parascapular flaps after lower limb trauma were examined six months postoperative. All ultrasound investigations were performed by one experienced examiner with a multi-frequency linear transducer (5-9 MHz, Logiq 9, GE). Flow evaluation was angle-optimized using digital image technology with the color coded Doppler sonography (CCDS) with measurement of the peak systolic, peak diastolic flow velocities and the resistance index (RI). Contrast harmonic imaging (CHI) with time intensity curve (TIC) analysis was used for quantitative evaluation of the tissue perfusion. Through a peripheral cubital cannula, a first bolus injection was made of 2.4 ml Sonovue to evaluate the perfusion near the flap center and the distal part of the flap.
The combined analysis of all 15 patients showed in the center and in the periphery of the flap a significant increase (p<0.01; Wilcoxon signed rank test) of the perfusion (relative units = RUs) in the period of 90-120 s after contrast medium application (center: baseline perfusion 2.23+/-0.31 RUs to 5.25+/-0.90 RUs after contrast medium; periphery: baseline perfusion 3.07+/-0.44 RUs to 5.80+/-0.57 RUs after contrast medium). The separate analysis of the non-bypass group (n=9) and bypass group (n=6) showed a clearly higher central flap perfusion after contrast medium application for the bypass group. The combined analysis of all patients showed RI-values amounting to 0.79+/-0.03. The RI-values of the bypass group were significantly higher than RI-values of the non-bypass group (p<0.05; t-test; p<0.05; Mann-Whitney rank sum test).
The high-resolution ultrasound represents an ideal method for detection of the flow and patency of the bypass and the small vessels of the free flap. The patency of microvascular anastomosis as well as the perfusion and microcirculation in different flap territories and tissue layers can be investigated using dynamic contrast-enhanced ultrasound with subtraction modalities.
Full-text · Article · Jan 2008 · Clinical hemorheology and microcirculation
[Show abstract][Hide abstract] ABSTRACT: The surgical treatment of aortoesophageal fistulae (AEF) has a high morbidity and mortality rate. We report our experience with the sequential use of endovascular thoracic stentgrafts and cryopreserved aortic homografts for in situ repair of the descending thoracic aorta.
In a 7-year period, 6 patients with AEF were treated at our center. After primary endovascular repair in all cases, 4 patients subsequently underwent in situ repair of the descending thoracic aorta with cryopreserved homografts. Long-term antibiotic therapy was given in all cases. Recent clinical status and radiologic findings on follow-up studies of each patient were analyzed. The mean follow-up time was 35 months (range, 2-76).
Endovascular stentgraft repair was technically successful in all cases. Two patients were not candidates for open surgical repair because of their medical condition; they both died within 8 weeks after discharge from the hospital, 1 from recurrent septic episodes, and the other from upper gastrointestinal bleeding. One of 4 patients who had undergone open surgical repair died 1 year later from upper gastrointestinal bleeding that occurred presumably due to an infectious degeneration of the homograft after secondary infection with a methacillin-resistant Staphyloccocus aureus. In 1 case persistent paraplegia and in another case persistent renal failure occurred.
The use of cryopreserved homografts is a valuable alternative to in situ repair with prosthetic vascular grafts or extra-anatomic reconstructions in the surgical treatment of AEF. Endovascular stentgraft placement plays a role as a bridging procedure in emergency situations.
No preview · Article · Dec 2007 · Annals of Surgery
[Show abstract][Hide abstract] ABSTRACT: The Anaconda prosthesis is a new endovascular device for abdominal aortic aneurysms repair.
of the study was to evaluate successful access to the arterial site, safety and efficacy of stent placement and fixation, assessment of endoleaks, patency of the graft due to twists, kinks or obstruction within the first 30 days after the procedure. Secondary objectives were the assessment of clinical success after 6 months due to graft patency and aneurysm exclusion without endoleak as well as the continuing clinical success without showing aneurysm expansion or any graft failure.
Between 2003 and 2006 a total of 14 patients with infrarenal aortic aneurysm (median diameter prior to endovascular treatment: 56.7 mm (range: 50 to 70 mm) were treated with the Anaconda endovascular device. 8 of these patients were treated in accordance to a prospective Phase II clinical study protocol (Anaconda ANA 004). 6 more patients received the same endovascular device after CE-certification.
Primary and secondary objectives were achieved in 12 of 14 patients after 6 months. In one patient insertion of the graft system was impossible due to kinking and circular calcification of the iliac arteries. Iliac access utilizing an alternative stent graft system (Cook, Zenith) was also unsuccessful. This patient underwent a conversion to open surgery and died. Another patient died 6 months after treatment unrelated to the procedure. A significant reduction of the median aneurysm diameter from 56.7 to 49.0 mm (range: 45 to 54 mm) was achieved after 6 months (p = 0.05). No endoleak was seen in the follow up.
Early results show that he Anaconda endovascular device for aneurysm repair is a safe and effective device for patients with suitable abdominal aortic aneurysms and proper distal access vessels which results in significant aneurysm diameter decrease and a low complication rate after 6 months of follow-up.
No preview · Article · Sep 2007 · VASA.: Zeitschrift für Gefässkrankheiten. Journal for vascular diseases
[Show abstract][Hide abstract] ABSTRACT: Four cases of proximal endostent instability after endovascular tube graft treatment of thoracic aortic disease using the TAG Gore system are reported. This potentially hazardous complication is characterized by a lack of attachment of the device to the small curvature of the aortic arch. Towering up against the hemodynamic forces in this area, the endograft could collapse and occlude the aorta. To identify this complication we recommend to perform an early postinterventional CT-scan with parasagittal reconstruction and an observation of the proximal endograft by fluorography. Endovascular solutions for the treatment of this complication may be either a proximal extension by another endograft or fixation of the proximal endograft by a balloon expandable Palmaz stent.
No preview · Article · Jul 2007 · Zentralblatt für Chirurgie
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the clinical value of color coded Doppler sonography (CCDS) and contrast-enhanced harmonic imaging (CHI) for ultrasound (US) monitoring the integrity of free-flap vascular grafts. Patency of microvascular anastomoses and perfusion as well as microcirculation of the transplanted tissue were analysed.
Fifteen free parascapular flap grafts performed over a period of three years by a single surgeon were examined with CCDS and CHI. The patients (12 male, 3 female) ranged in age from 16 to 60 years (average age 40+/-12). The follow-up period ranged from two weeks to 2.5 years. CCDS were performed with a multifrequency linear transducer (5-10 MHz, Logiq 9, GE) with 3D flow detection. For detection and characterization, B scan of the flap tissue was compared to tissue harmonic imaging (THI) and Cross Beam with Speckle Reduction Imaging (SRI). US Pulse Inversion Harmonic Imaging (PIHI) after bolus injection of 2.5 ml Sonovue was used for contrast enhancement.
Border and tissue structure of the flaps could be detected best in all 15/15 cases using Cross Beam Technology with SRI and THI. Correlations were found for flow parameters of the common femoral artery, popliteal artery and lower leg artery to the anastomotic vessels. 3D imaging with CCDS facilitated flow detection of elongated and small anastomotic vessels in 4/15 cases. Contrast-enhanced US with PIHI allowed dynamic flow detection of the microcirculation of the transplanted tissue over a depth of up to 3 cm with quantitative perfusion curves of the tissue microcirculation. Reduced US contrast enhancement with modified perfusion curves was seen in 2/15 cases with low anastomic flow in CCDS.
Assessment of microvascular perfusion with contrast-enhanced ultrasound can provide valuable information on free flap viability. Contrast-enhanced US enables dynamic and quantitative flow detection of free flap tissue.
No preview · Article · Feb 2007 · Clinical hemorheology and microcirculation
[Show abstract][Hide abstract] ABSTRACT: We report two cases of proximal endograft collapse with an almost complete aortic occlusion after endovascular tube-graft treatment of thoracic aortic disease (thoracic aneurysm after a type B dissection, traumatic blunt aortic rupture) using the TAG Gore system. Oversizing of endografts is known to cause this complication. In our two cases, however, the oversizing was between 12% and 21.7%, which is less than the allowed oversizing of 25% that is recommended by the manufacturer. This endograft-related complication might be due to a poor alignment of the currently available endografts in highly angulated and tight aortic arches. In the first case, a combined endovascular and open emergent repair procedure achieved a reopening of the proximal endograft by proximal extension (TAG Gore). In the second case, proximal extension was not considered owing to a precise positioning of the endograft distal to the left carotid artery. A balloon-expanding Palmaz stent was therefore placed interventionally in the proximal part of the TAG graft to expand the endograft and to avoid another collapse of the device. This proximal endograft collapse has to be acknowledged as a potentially hazardous complication. We therefore recommend that the proximal part of thoracic endografts in the aortic arch should be closely monitored and we offer two possible endovascular solutions for resolving the problem of proximal endograft collapse.
Full-text · Article · Apr 2006 · Journal of Vascular Surgery
[Show abstract][Hide abstract] ABSTRACT: To investigate whether the plasma disappearance rate of indocyanine green (ICG) assessed using a commercially available bedside monitor provides an accurate estimation of cumulative biliary ICG excretion in a clinically relevant model of long-term, hyperdynamic porcine endotoxemia.
Prospective experimental study in the animal laboratory in a university hospital.
Fifteen domestic pigs.
Pigs were anesthetized, mechanically ventilated, and instrumented. Intravenous endotoxin was continuously infused over 12 h concomitant with fluid resuscitation. Measurements were performed before and 12 h after the start of endotoxin infusion.
All animals developed hyperdynamic circulation characterized by a sustained increase in cardiac output. Despite well maintained portal venous and consequently total liver blood flow endotoxemia decreased hepatic lactate uptake, which was accompanied by a significant fall in portal and hepatic venous pH. Both the cumulative bile flow and biliary ICG and bicarbonate excretion measured during 1 h after intravenous bolus of 25 mg ICG fell significantly. By contrast, neither the plasma disappearance rate of ICG nor the rate corrected for liver blood flow exhibited any changes over time.
In hyperdynamic porcine endotoxemia the plasma disappearance rate of ICG failed to accurately substitute for direct short-term measures of biliary ICG excretion. Hence normal values of plasma disappearance rate of ICG should be interpreted with caution in early, acute inflammatory conditions.
No preview · Article · Jan 2006 · Intensive Care Medicine
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to demonstrate the possibility of performing magnetic resonance (MR)-guided interventional therapy for femoral and popliteal artery stenoses with commercially available materials supported by MR real-time imaging and intra-arterial MR angiography.
A total of 15 patients suffering from symptomatic arterial occlusive disease of the lower limbs with 19 stenoses were included. Interventional intra-arterial digital subtraction angiography was performed before and after angioplasty on each patient as standard of reference. MR images were acquired on a 1.5-T MR scanner. A fast-low-angle shot (FLASH) 3D sequence was applied for a contrast enhanced MR-angiography (ceMRA). A total of 5 mL of diluted gadodiamide was injected via the arterial access. Maximum intensity projections (MIPs) were used as roadmaps and localizers for the interactive positioning of a continuously running 2D-FLASH sequence with a temporal solution of 2 images/second. The lesion was crossed by a balloon-catheter, which was mounted on a guidewire. The visibility was provided by the radiopaque markers on the balloon and was improved by injection of 1 mL of gadolinium into the balloon. Postinterventional control was performed by intra-arterial MR angiography and catheter angiography.
Stenoses were localized by intra-arterial MR angiography. The guidewire/balloon combination was visible, and the balloon was placed correctly to cover the entire stenoses. Balloon dilation reduced the degree of stenosis by approximately 57% on average. No complications were observed.
MR-guided balloon dilation of femoral and popliteal artery stenoses supported by real-time MR imaging and intra-arterial MR angiography is feasible with commercially available materials.
No preview · Article · Jun 2005 · Investigative Radiology