Significant differences in functional outcome between upper and lower limbs after vascular trauma of the extremities.

BACKGROUND: This study aimed to compare the functional results between upper (UE) and lower extremity (LE) following arterial reconstruction due to vascular trauma. METHODS: Patients treated for arterial injuries with vascular reconstruction at two centres between 2005 and 2014 were assessed. The physical fitness questionnaire - Fitnessfragebogen (FFB-Mot) - was evaluated. The differences between pre- and post-traumatic values were compared statistically for UE and LE. Inability to return to the preoperative workplace or postoperative loss of at least 10% of the FFB-Mot were defined as the primary outcome events. RESULTS: Twenty-seven patients could be re-evaluated. The primary outcome event occurred in 52% (14/27) without significant difference between UE (43%) and LE (62%) (p = 0.45). The difference between the pre- and post-traumatic FFB-Mot scores showed a significantly poorer functional outcome after LE vascular injury (p = 0.012). CONCLUSION: Results indicate a poorer functional outcome after vascular extremity trauma to the LE than to the UE.

[Interdisciplinary position paper "Perioperative pain management"]. / Interdisziplinäres Positionspapier "Perioperatives Schmerzmanagement".

Despite many positive developments, postoperative pain and its treatment is still not always given the necessary attention. Severe pain after surgical procedures affects a significant proportion of patients. This very fact is not only detrimental to the immediate recovery process, but can also form the basis for the development of chronic pain conditions.An adequate and effective management of perioperative pain requires appropriate organizational structures. This multidisciplinary paper which was initiated by the Austrian Society for Anaesthesiology and Intensive Care and the Austrian Pain Society and developed together with numerous specialist and professional societies dealing with the subject aims at supporting the organization of perioperative pain management structures and to make best use of proven concepts. Additional recommendations describe specific interventions for selected types of intervention.

Impact of Staphylococcus aureus protein A (spa) genetic typing in cases of prosthetic shunt graft infections.

INTRODUCTION: In January 2014 an internal audit was performed at the department of surgery, division of vascular surgery of the Medical University Graz, Austria, to assess the short and long-term outcomes of prosthetic shunt graft implantations performed between December 1998 and December 2013. A 10.8 % explantation rate due to graft infection was detected. The majority of the cases were associated with Staphylococcus aureus. The aim of this study was to clarify whether this constitutes a nosocomial problem. PATIENTS AND METHODS: Between December 1998 and December 2014 a total of 490 prosthetic shunt grafts were implanted. After exclusion of 54 cases, 436 shunts remained for statistical analysis. Genetic analysis (spa typing) was acquired from three new cases with involvement of S. aureus in 2014. The impact of several factors (e.g. sex, institute for dialysis, age, type of prosthesis, implantation surgeon and position of shunt) on the shunt graft infection rate was statistically analyzed. RESULTS: Of the prostheses 14.0 % (61 out of 436) had to be explanted of which 12.4 % (54/436) were due to infection. In 77.8 % (42/54) bacteria were found in blood and/or wound cultures. Staphylococcus aureus was present in 76.2 % (32/42) of the cases with detected bacteria and in all cases was sensitive to methicillin. The infection rate was not significantly dependent on any of the investigated factors; however, the factor "institute for dialysis" had a remarkable p­value of 0.060 with the infection rate ranging from 8.5 % to 18.2 % depending on the institution. Three different S. aureus protein A (spa) types were found: t015, t359, t6265. The detection of three different spa types means that these patients had different sources of S. aureus so that a nosocomial problem is very unlikely. CONCLUSION: Genetic typing of spa is a suitable technique for distinguishing between nosocomial and community acquired sources of prosthetic shunt graft infections.

Diameter-related variations of geometrical, mechanical, and mass fraction data in the anterior portion of abdominal aortic aneurysms.

OBJECTIVE: Maximum aortic diameter is an important measure in rupture prediction of abdominal aortic aneurysms (AAAs). Analyzing the variations of geometrical, material, and biochemical properties with increased AAA diameters advances understanding of the effect of lesion enlargement on patient specific vascular properties. METHODS: 96 AAA samples were harvested during open surgical aneurysm repair. Geometrical factors such as the maximum intraluminal thrombus (ILT) thickness, wall thickness, and AAA expansion rate were measured. Biaxial extension and peeling tests were performed to characterize the biaxial mechanical responses and to quantify the dissection properties of aneurysmal tissue. Mass fraction analysis quantified the dry weight percentages of elastin and collagen within the AAA wall. Linear regression models were used to correlate geometrical, mechanical, and mass fraction data with maximum AAA diameter. RESULTS: Both ILT thickness and AAA expansion rate increased and were positively correlated with maximum AAA diameter, while there was a slight increase in wall thickness for AAAs with a larger maximum diameter. For the biaxial mechanical responses, mean peak stretches and maximum tangential moduli in the circumferential and longitudinal axes did not correlate with maximum AAA diameters. However, the quantified energy to propagate tissue dissections within intima-media composites showed a significant inverse correlation with maximum AAA diameter. Elastin content decreased significantly with increasing AAA diameter. CONCLUSION: Larger AAA diameters are associated with thicker ILTs, higher AAA expansion rates, and pronounced elastin loss, and may also lead to a higher propensity for tissue dissection and aneurysm rupture.

Variations of dissection properties and mass fractions with thrombus age in human abdominal aortic aneurysms.

INTRODUCTION: Thrombus ages, defined as four relative age phases, are related to different compositions of the intraluminal thrombus (ILT) in the abdominal aortic aneurysm (AAA) (Tong et al., 2011b). Experimental studies indicate a correlation between the relative thrombus age and the strength of the thrombus-covered wall. METHODS: On 32 AAA samples we performed peeling tests with the aim to dissect the material (i) through the ILT thickness, (ii) within the individual ILT layers and (iii) within the aneurysm wall underneath the thrombus by using two extension rates (1mm/min, 1mm/s). Histological investigations and mass fraction analysis were performed to characterize the dissected morphology, to determine the relative thrombus age, and to quantify dry weight percentages of elastin and collagen in the AAA wall. RESULTS: A remarkably lower dissection energy was needed to dissect within the individual ILT layers and through the thicknesses of old thrombi. With increasing ILT age the dissection energy of the underlying intima-media composite continuously decreased and the anisotropic dissection properties for that composite vanished. The quantified dissection properties were rate dependent for both tissue types (ILT and wall). Histology showed that single fibrin fibers or smaller protein clots within the ILT generate smooth dissected surfaces during the peeling. There was a notable decrease in mass fraction of elastin within the thrombus-covered intima-media composite with ILT age, whereas no significant change was found for that of collagen. CONCLUSIONS: These findings suggest that intraluminal thrombus aging leads to a higher propensity of dissection for the ILT and the intima-media composite of the aneurysmal wall.

Gender differences in biomechanical properties, thrombus age, mass fraction and clinical factors of abdominal aortic aneurysms.

OBJECTIVE: The main purpose of the present study is the investigation of gender differences in the biomechanical properties, thrombus age, mass fraction and key clinical factors of abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS: A total of 90 AAA samples (78 males and 12 females) were harvested from open surgical aneurysm repairs. Biaxial extension and peeling tests were performed to characterise the biaxial mechanical responses and to determine dissection properties of both the intraluminal thrombi (ILTs) and the thrombus-covered walls. Relative thrombus age was determined by characterising the ILT histological microstructure. Mass fraction analyses quantified dry weight percentages of elastin and collagen within the AAA walls. Moreover, we statistically compared clinical factors between male and female. RESULTS: The luminal layers of the female thrombi and the female AAA walls showed a significantly lower tissue stiffness (modulus) in the longitudinal direction when compared to males. Gender differences were also shown in the dissection properties of the intima-media composite within the AAA walls, in which a statistically significantly lower energy to propagate a dissection was quantified for females than for males. Moreover, 82% of female thrombi were relatively older (ILT age phases III and IV), twice that of male thrombi (43%). A pronounced lower elastin content was identified for the intima-media composites of male AAA walls, whereas female AAA walls had significantly lower dry weight percentages of collagen. Regarding clinical factors, nicotine pack years, serum creatinine and AAA expansion rate were found to be much higher for male patients. CONCLUSION: These findings may help to explain higher risks for AAA growth in males and the ruptures of smaller-sized AAAs in females.

Paraganglioma of the carotid body: treatment strategy and SDH-gene mutations.

OBJECTIVES: The aim of the present study was to review treatment results in patients with paraganglioma (PGL) of the neck presenting as carotid body tumour, long-term follow-up and relevance of genetic testing for succinate dehydrogenase (SDH)-gene mutations. DESIGN: Retrospective analysis of prospectively collected data and prospective genetic analysis. MATERIALS AND METHODS: Over a 25-year period (1987-2011) 50 patients were operated for 63 PGLs of the neck. Pre-, intra- and postoperative findings were analysed. Sanger sequencing was performed for genetic testing of SDH-gene mutations (SDH B, SDHC and SDHD). RESULTS: Fifty patients underwent resection of 63 PGLs (62 benign, one malignant) without mortality. Eight patients underwent preoperative embolisation. Vascular surgical procedures were required in 15 operations (15/63 = 23.8%). Nerve lesions occurred after 13 operations (13/63 = 20.6%) and were associated with large tumours. A total of 44 patients are alive after a mean follow-up of 9.8 years. In 40 patients 17 SDH-gene mutations were detected (17/40 = 42.5%): 14 SDHD mutations, two SDHB mutations and one rare SDHC mutation. CONCLUSION: Surgery for PGL is recommended. All PGL patients should be screened for SDH mutations because it impacts the individual follow-up strategy. Whereas all PGL patients require annual ultrasound control, mutation carriers and family members with proven mutations should in addition be regularly examined by magnetic resonance imaging (MRI) of head, neck, thorax, abdomen and pelvis.

Long-term follow-up of vascular reconstructions after supracondylar humerus fracture with vascular lesion in childhood.

INTRODUCTION: Supracondylar humerus fractures in childhood present with a pulseless but well-perfused hand in 2.6% of cases and with limb-threatening ischaemia in <1%. Conservative treatment is widely used in non-limb-threatening ischaemia, in particular if the child is very young (<2.5 years). It has been sufficiently proven that conservative treatment may retard growth. The aim of our study was to determine long-term patency rates after surgical reconstruction and growth impairment, if any, after surgical vascular reconstruction. PATIENTS AND METHODS: Between June 1990 and June 2004, 12 children (mean age 6.6 years, eight boys and four girls) with supracondylar fracture with vascular lesions underwent surgical reconstruction at the Department of Vascular Surgery at the University Hospital, Graz. Patient files were reviewed retrospectively. All patients were recalled for physical (forearm length and volume) and ultrasonographic examinations (forearm blood flow) in 2005 and for ultrasonographic examinations (reconstructed vascular area) in 2011, with a final mean follow-up time of 14.0 years (range 6.8-20.9 years). RESULTS: Twelve patients, 10 of whom had undergone growth measurements in 2005, were available for the latter examination. All were doing well, with patent vascular reconstructions. Seven reconstructed brachial arteries were enlarged, two of which with intramural calcifications, four did not show abnormalities and one presented with 45% thinning. There were no differences between affected and healthy forearms concerning volume, length and blood flow. CONCLUSIONS: Our data emphasise that surgical reconstruction is effective in terms of blood supply and growth. In cases with interposition of greater saphenous vein or venous patch plasty, we found a high risk for development of enlargements. We suggest that these patients be followed periodically, with ultrasound studies, to detect aneurysms and/or thrombotic changes as early as possible.

Effects of age on the elastic properties of the intraluminal thrombus and the thrombus-covered wall in abdominal aortic aneurysms: biaxial extension behaviour and material modelling.

OBJECTIVE: The intraluminal thrombus (ILT) present in the majority of abdominal aortic aneurysms (AAAs) plays an important role in aneurysm wall weakening. Studying the age-dependent elastic properties of the ILT and the thrombus-covered wall provides a better understanding of the potential effect of ILT on AAA remodelling. MATERIALS AND METHODS: A total of 43 AAA samples (mean age 67 ± 6 years) including ILT and AAA wall was harvested. Biaxial extension tests on the three individual ILT layers and the thrombus-covered wall were performed. Histological investigations of the thrombi were performed to determine four different age phases, and to correlate with the change in the mechanical properties. A three-dimensional material model was fitted to the experimental data. RESULTS: The luminal layers of the ILT exhibit anisotropic stress responses, whereas the medial and the abluminal layers are isotropic materials. The stresses at failure in the equibiaxial protocol continuously decrease from the luminal to the abluminal side, whereby cracks, mainly oriented along the longitudinal direction, can be observed in the ruptured luminal layers. The thrombi in the third and fourth phases contribute to wall weakening and to an increase of the mechanical anisotropy of their covered walls. The material models for the thrombi and the thrombus-covered walls are in excellent agreement with the experimental data. CONCLUSION: Our results suggest that thrombus age might be a potential predictor for the strength of the wall underneath the ILT and AAA rupture.

Outcome of patients after cardiac surgery transferred to other hospitals following prolonged intensive care stay.

BACKGROUND: The steady rise in complex cardiac procedures as well as the increase in comorbidity often result in a prolonged intensive care unit (ICU) stay. As a consequence, considerable numbers of patients have to be transferred to other hospitals so that the primary institution can maintain its capacity. The purpose of this study was to investigate the outcome of these patients. METHODS: 1,175 consecutive patients underwent various open heart procedures. 115 patients (9.8 %) requiring prolonged ICU treatment were retrospectively analyzed. 74 patients (EuroSCORE 8.1) underwent transferral to either rehabilitation units with ventilation capacity, multidisciplinary ICUs, or cardiac ICUs. 41 patients (EuroSCORE 7.9) remained in our hospital. Morbidity, mortality, and clinical condition were assessed and compared. RESULTS: Transferred patients exhibited an overall mortality of 38 % compared to only 17 % in patients who remained. Mortality was 81 % in rehabilitation units, 30 % in multidisciplinary ICUs, and 16 % in cardiac ICUs. 66 % of the survivors among the transferred patients showed significantly impaired clinical condition (NYHA III-IV) compared to 33 % who showed a good postoperative condition (NYHA I-II). The patients who remained exhibited 44 % NYHA III-IV and 56 % NYHA I-II. CONCLUSION: Transferral of patients after prolonged intensive care stay to external hospitals carries significant risks for early death and impaired outcome. However, transferral to cardiac ICUs appears to be an adequate option. Further studies may identify potential subgroups of patients who do not benefit from transferral.

Coronary artery bypass grafting surgery without the routine application of blood products: Is it feasible?

OBJECTIVE: Fresh frozen plasma (FFP) substitution is currently standard practise in cardiac surgery. In this study we investigate whether elective coronary artery bypass grafting (CABG) surgery is feasible without the administration of blood products compared to the substitution of fresh frozen plasma. PATIENTS AND METHODS: From September 1997 to April 1998, 120 consecutive patients underwent CABG surgery at our institution. In the FFP group patients (n=60; men, n=43; women, n=17; mean age: 64+/-8.5 years) received 4 units of fresh frozen plasma (FFP) intraoperatively. In comparison, patients in the control group (n=60; men, n=44; women, n=16; mean age: 65+/-7.5 years) did not receive FFP. Main endpoints included perioperative hematologic parameters, blood loss, and the amount of blood products that were administered. RESULTS: Intraoperatively, the substitution of packed red blood cells (pRBC) in the FFP group was significantly higher compared with the control group (0.63+/-0.94 units/patient vs. 0.12+/-0.38 units/patient, P=0.001). Postoperatively, patients in the FFP group required significantly more pRBC products than patients in the control group (0.78+/-1.09 vs. 0.42+/-0.77, P=0.024). There were no significant differences in hemoglobin (FFP group: 99+/-11.1 g/dl; control group: 105+/-13.5 g/dl) and hematocrit levels (FFP group: 30+/-3.39%; control group: 32+/-4%). Also, no significant differences regarding the postoperative blood loss was observed between groups (FFP group: 588+/-224 vs. control group: 576+/-272 ml/24 h). CONCLUSIONS: This study clearly demonstrates that the avoidance of routine intraoperative FFP administration does not lead to an increase in blood loss postoperatively compared to patients that received FFPs. Furthermore, we did not observe increased requirements for postoperative FFP infusion in patients that did not receive FFPs intraoperatively.

Retrograde versus antegrade crystalloid cardioplegia in coronary surgery: value of troponin-I measurement.

BACKGROUND: The optimal route for delivery of cardioplegia is still in debate in patients with ischemic heart disease. Cardiac troponin-I is a new marker with the potential for detection of minor differences in myocardial ischemia. METHODS: In a prospective randomized trial 58 patients undergoing elective coronary artery bypass grafting for two- or three-vessel coronary artery disease were divided into groups with antegrade (group A, n = 29) and retrograde (group R, n = 29) application of crystalloid cardioplegia (St. Thomas II). Patients with major risk factors were excluded. In addition to routine electrocardiogram monitoring, cardiac troponin-I and creatine kinase-MB activity were measured in all patients preoperatively at 2, 5, 8, 24, and 48 hours after aortic cross-clamp release, and at hospital discharge. RESULTS: In both groups, there were no differences regarding operative parameters. A significantly higher cardiac troponin-I concentration was observed in the antegrade group at 24 hours after cross-clamp (8.2 +/- 8.5 microg/L vs 3.2 +/- 3.1 microg/L; p = 0.02). Patients with subtotal stenosis or occlusion of one or more main coronary arteries showed significantly lower cardiac troponin-I levels after retrograde application. CONCLUSIONS: Lower concentrations of the cardiac troponin-I marker after retrograde application of cardioplegia indicate advantages of myocardial protection in ischemic heart disease.

Intramyocardial electrogram recordings (IMEG) for diagnosis of cellular and humoral mediated cardiac allograft rejection.

OBJECTIVE: The purpose of this study was to prove the reliability of intramyocardial electrogram (IMEG) recordings for diagnosis and treatment monitoring of (1) cellular and (2) humoral mediated allograft rejection after heart transplantation. MATERIAL AND METHODS: Fifteen beagle dogs underwent heterotopic neck-heart transplantation. Eight of them were previously sensitized through several skin transplantations. IMEG recordings were performed daily. Donor-specific antibodies (IgG, IgM) were determinated in serum daily. Transmyocardial biopsies were performed every two days. RESULTS: In the sensitized group (group I) accelerated rejection occurred under triple drug immunosuppression with cyclosporine A, azathioprine, and cortisone on the fifth postoperative day (range: 4th-5th). All episodes were detected through IMEG diagnosis. In each case rejection could be treated successfully. In the cellular mediated group (group II), the average sensitivity for rejection diagnosis of a single lead was 24% for the unipolar and 42% for the bipolar leads. When the voltages of different leads were summed up the sensitivity rose to 36% (3 unipolar), 81% (3 bipolar) and 100% (all leads). During rejection therapy the IMEG recovered within 24-48 hours. CONCLUSION: The IMEG detects cellular and humoral mediated rejection early and with high reliability. The rejection-related changes of grade 2/3a rejection in IMEG seem to follow a Ofocal patternO similar to the histology. Therefore the recording of several, preferably bipolar, electrode configurations appears to enhance diagnostic reliability.

Matched-pair analysis of conventional versus endoluminal AAA treatment outcomes during the initial phase of an aortic endografting program.

PURPOSE: To investigate whether endovascular stent-grafts implanted during the early phase of an aortic endografting program have advantages over conventional surgical procedures for treatment of infrarenal aortic aneurysm (AAA). METHODS: In the first months of an endografting program, 37 patients (36 men; mean age 67.9 +/- 7.1 years, range 55 to 86) underwent AAA repair with endovascular implantation of a Vanguard (n = 17) or Talent (n = 20) bifurcated stent-graft. Data collected during the perioperative period and in follow-up were compared retrospectively to a matched group of 37 elective surgical patients. RESULTS: All endograft implantations were completed. Two type I and 6 type II endoleaks (21.6%) were seen postoperatively. Five type II sealed without intervention; 1 type I endoleak was corrected with an additional stent, but 1 type I and 1 type II endoleaks persisted despite attempts with coil embolization. Two (5.4%) endograft patients died during the perioperative period; however, this was not significantly different (p = 0.15) from the control group. In the mean follow-up of 12 +/- 6 months for both groups, 1 (2.7%) late conversion was necessary at 2 years for aneurysm expansion in an endograft patient with an unsealed type I endoleak. CONCLUSIONS: In our learning curve experience with aortic endografting, postoperative morbidity and mortality were higher in endograft patients compared to conventionally treated controls. Only in the endograft group was reoperation required during follow-up. Careful monitoring with periodic imaging studies is mandatory after endoluminal AAA treatment.