Matched-pair analysis of endovascular versus open surgical repair of abdominal aortic aneurysms in young patients at low risk

PURPOSE: To compare clinical outcomes of endovascular and open aortic repair of abdominal aortic aneurysms (AAAs) in young patients at low risk. It was hypothesized that endovascular aneurysm repair (EVAR) compares favorably with open aneurysm repair (OAR) in these patients. MATERIALS AND METHODS: Twenty-five patients aged 65 years or younger with a low perioperative surgical risk profile underwent EVAR at a single institution between April 1994 and May 2007 (23 men; mean age, 62 years+/-2.8). A sex- and risk-matched control group of 25 consecutive patients aged 65 years or younger who underwent OAR was used as a control group (23 men; mean age, 59 years+/-3.9). Patient outcomes and complications were classified according to Society of Vascular Surgery/International Society for Cardiovascular Surgery reporting standards. RESULTS: Mean follow-up times were 7.1 years+/-3.2 after EVAR and 5.9 years+/-1.8 after OAR (P=.1020). Total complication rates were 20% after EVAR and 52% after OAR (P=.0378), and all complications were mild or moderate. Mean intensive care unit times were 0.2 days+/-0.4 after EVAR and 1.1 days+/-0.4 after OAR (P<.0001) and mean lengths of hospital stay were 2.3 days+/-1.0 after EVAR and 5.0 days+/-2.1 after OAR (P<.0001). Cumulative rates of long-term patient survival did not differ between EVAR and OAR (P=.144). No AAA-related deaths or aortoiliac ruptures occurred during follow-up for EVAR and OAR. In addition, no surgical conversions were necessary in EVAR recipients. Cumulative rates of freedom from secondary procedures were not significantly different between the EVAR and OAR groups (P=.418). Within a multivariable Cox proportional-hazards analysis adjusted for patient age, maximum AAA diameter, and cardiac risk score, all-cause mortality rates (odds ratio [OR], 0.125; 95% CI, 0.010-1.493; P=.100) and need for secondary procedures (OR, 5.014; 95% CI, 0.325-77.410; P=.537) were not different between EVAR and OAR. CONCLUSIONS: Results from this observational study indicate that EVAR offers a favorable alternative to OAR in young patients at low risk.

Diversity of the basic defect of homozygous CFTR mutation genotypes in humans

BACKGROUND: Knowledge of how CFTR mutations other than F508del translate into the basic defect in cystic fibrosis (CF) is scarce due to the low incidence of homozygous index cases. METHODS: 17 individuals who are homozygous for deletions, missense, stop or splice site mutations in the CFTR gene were investigated for clinical symptoms of CF and assessed in CFTR function by sweat test, nasal potential difference and intestinal current measurement. RESULTS: CFTR activity in sweat gland, upper airways and distal intestine was normal for homozygous carriers of G314E or L997F and in the range of F508del homozygotes for homozygous carriers of E92K, W1098L, R553X, R1162X, CFTRdele2(ins186) or CFTRdele2,3(21 kb). Homozygotes for M1101K, 1898+3 A-G or 3849+10 kb C-T were not consistent CF or non-CF in the three bioassays. 14 individuals exhibited some chloride conductance in the airways and/or in the intestine which was identified by the differential response to cAMP and DIDS as being caused by CFTR or at least two other chloride conductances. DISCUSSION: CFTR mutations may lead to unusual electrophysiological or clinical manifestations. In vivo and ex vivo functional assessment of CFTR function and in-depth clinical examination of the index cases are indicated to classify yet uncharacterised CFTR mutations as either disease-causing lesions, risk factors, modifiers or neutral variants.

Frequency of severe pulmonary hypertension complicating "isolated" atrial septal defect in infancy

Atrial septal defects (ASDs) are typically asymptomatic in infancy and early childhood, and elective defect closure is usually performed at ages of 4 to 6 years. Severe pulmonary hypertension (PH) complicating an ASD is seen in adulthood and has only occasionally been reported in small children. A retrospective study was undertaken to evaluate the incidence of severe PH complicating an isolated ASD and requiring early surgical correction. During a 10-year period (1996 to 2006), 355 pediatric patients underwent treatment for isolated ASDs either surgically or by catheter intervention at 2 tertiary referral centers. Two hundred ninety-seven patients had secundum ASDs, and 58 had primum ASDs with mild to moderate mitral regurgitation. Eight infants were found with isolated ASDs (6 with secundum ASDs and 2 with primum ASDs) associated with significant PH, accounting for 2.2% of all patients with ASDs at the centers. These 8 infants had invasively measured pulmonary artery pressures of 50% to 100% of systemic pressure. They were operated in the first year of life and had complicated postoperative courses requiring specific treatment for PH for up to 16 weeks postoperatively. The ultimate outcomes in all 8 infants were good, with persistent normalization of pulmonary pressures during midterm follow-up of up to 60 months (median 28). All other patients with ASDs had normal pulmonary pressures, and the mean age at defect closure was significantly older, at 6.2 years for secundum ASDs and 3.2 years for primum ASDs. In conclusion, ASDs were rarely associated with significant PH in infancy but then required early surgery and were associated with excellent midterm outcomes in these patients.

Compatibility of ultra high performance concrete as repair material : bond characterization with concrete under different loading scenarios

The rehabilitation of concrete structures, especially concrete bridge decks, is a major challenge for transportation agencies in the United States. Often, the most appropriate strategy to preserve or rehabilitate these structures is to provide some form of a protective coating or barrier. These surface treatments have typically been some form of polymer, asphalt, or low-permeability concrete, but the application of UHPC has shown promise for this application mainly due to its negligible permeability, but also as a result of its excellent mechanical properties, self-consolidating nature, rapid gain strength, and minimal creep and shrinkage characteristics. However, for widespread acceptance, durability and performance of the composite system must be fully understood, specifically the bond between UHPC and NSC often used in bridge decks. It is essential that the bond offers enough strength to resist the stress due to mechanical loading or thermal effects, while also maintaining an extended service-life performance. This report attempts to assess the bond strength between UHPC and NSC under different loading configurations. Different variables, such as roughness degree of the concrete substrates, age of bond, exposure to freeze-thaw cycles and wetting conditions of the concrete substrate, were included in this study. The combination of splitting tensile test with 0, 300, 600 and 900 freeze-thaw cycles was carried out to assess the bond performance under severe ambient conditions. The slant-shear test was utilized with different interface angles to provide a wide understanding of the bond performance under different combinations of compression and shear stresses. The pull-off test is the most accepted method to evaluate the bond strength in the field. This test which studies the direct tensile strength of the bond, the most severe loading condition, was used to provide data that can be correlated with the other tests that only can be used in the laboratory. The experimental program showed that the bond performance between UHPC and NSC is successful, as the strength regardless the different degree of roughness of the concrete substrate, the age of the composite specimens, the exposure to freeze-thaw cycles and the different loading configurations, is greater than that of concrete substrate and largely satisfies with ACI 546.3R-06.

MRI monitoring of cartilage repair in the knee: a review

Various treatment options for deep cartilage defects are presently available. The efficacy of bone marrow stimulation with microfracture, of mosaicplasty and of various autologous chondrocyte implantation (ACI) techniques has been subject to numerous studies recently. Magnetic resonance imaging (MRI) has gained a major role in the assessment of cartilage repair. The introduction of high-field MRI to clinical routine makes high resolution and three-dimensional imaging readily available. New quantitative MRI techniques that directly visualize the molecular structure of cartilage may further advance our understanding of cartilage repair. The clinical evaluation of cartilage repair tissue is a complex issue, and MR imaging will become increasingly important both in research and in clinical routine. This article reviews the clinical aspects of microfracture, mosaicplasty, and ACI and reports the recent technical advances that have improved MRI of cartilage. Morphological evaluation methods are recommended for each of the respective techniques. Finally, an overview of T2 mapping and delayed gadolinium-enhanced MR imaging of cartilage in cartilage repair is provided.

Advanced morphological and biochemical magnetic resonance imaging of cartilage repair procedures in the knee joint at 3 Tesla

Morphological and biochemical magnetic resonance imaging (MRI) is due to high field MR systems, advanced coil technology, and sophisticated sequence protocols capable of visualizing articular cartilage in vivo with high resolution in clinical applicable scan time. Several conventional two-dimensional (2D) and three-dimensional (3D) approaches show changes in cartilage structure. Furthermore newer isotropic 3D sequences show great promise in improving cartilage imaging and additionally in diagnosing surrounding pathologies within the knee joint. Functional MR approaches are additionally able to provide a specific measure of the composition of cartilage. Cartilage physiology and ultra-structure can be determined, changes in cartilage macromolecules can be detected, and cartilage repair tissue can thus be assessed and potentially differentiated. In cartilage defects and following nonsurgical and surgical cartilage repair, morphological MRI provides the basis for diagnosis and follow-up evaluation, whereas biochemical MRI provides a deeper insight into the composition of cartilage and cartilage repair tissue. A combination of both, together with clinical evaluation, may represent a desirable multimodal approach in the future, also available in routine clinical use.

Magnetization transfer contrast and T2 mapping in the evaluation of cartilage repair tissue with 3T MRI

PURPOSE: To use magnetization transfer (MT) imaging in the visualization of healthy articular cartilage and cartilage repair tissue after different cartilage repair procedures, and to assess global as well as zonal values and compare the results to T2-relaxation. MATERIALS AND METHODS: Thirty-four patients (17 after microfracture [MFX] and 17 after matrix-associated autologous cartilage transplantation [MACT]) were examined with 3T MRI. The MT ratio (MTR) was calculated from measurements with and without MT contrast. T2-values were evaluated using a multiecho, spin-echo approach. Global (full thickness of cartilage) and zonal (deep and superficial aspect) region-of-interest assessment of cartilage repair tissue and normal-appearing cartilage was performed. RESULTS: In patients after MFX and MACT, the global MTR of cartilage repair tissue was significantly lower compared to healthy cartilage. In contrast, using T2, cartilage repair tissue showed significantly lower T2 values only after MFX, whereas after MACT, global T2 values were comparable to healthy cartilage. For zonal evaluation, MTR and T2 showed a significant stratification within healthy cartilage, and T2 additionally within cartilage repair tissue after MACT. CONCLUSION: MT imaging is capable and sensitive in the detection of differences between healthy cartilage and areas of cartilage repair and might be an additional tool in biochemical cartilage imaging. For both MTR and T2 mapping, zonal assessment is desirable.

Cartilage T2 assessment at 3-T MR imaging: in vivo differentiation of normal hyaline cartilage from reparative tissue after two cartilage repair procedures--initial experience

PURPOSE: To prospectively compare cartilage T2 values after microfracture therapy (MFX) and matrix-associated autologous chondrocyte transplantation (MACT) repair procedures. MATERIALS AND METHODS: The study had institutional review board approval by the ethics committee of the Medical University of Vienna; informed consent was obtained. Twenty patients who underwent MFX or MACT (10 in each group) were enrolled. For comparability, patients of each group were matched by mean age (MFX, 40.0 years +/- 15.4 [standard deviation]; MACT, 41.0 years +/- 8.9) and postoperative interval (MFX, 28.6 months +/- 5.2; MACT, 27.4 months +/- 13.1). Magnetic resonance (MR) imaging was performed with a 3-T MR imager, and T2 maps were calculated from a multiecho spin-echo measurement. Global, as well as zonal, quantitative T2 values were calculated within the cartilage repair area and within cartilage sites determined to be morphologically normal articular cartilage. Additionally, with consideration of the zonal organization, global regions of interest were subdivided into deep and superficial areas. Differences between cartilage sites and groups were calculated by using a three-way analysis of variance. RESULTS: Quantitative T2 assessment of normal native hyaline cartilage showed similar results for all patients and a significant trend of increasing T2 values from deep to superficial zones (P < .05). In cartilage repair areas after MFX, global mean T2 was significantly reduced (P < .05), whereas after MACT, mean T2 was not reduced (P > or = .05). For zonal variation, repair tissue after MFX showed no significant trend between different depths (P > or = .05), in contrast to repair tissue after MACT, in which a significant increase from deep to superficial zones (P < .05) could be observed. CONCLUSION: Quantitative T2 mapping seems to reflect differences in repair tissues formed after two surgical cartilage repair procedures. (c) RSNA, 2008.

Differentiating normal hyaline cartilage from post-surgical repair tissue using fast gradient echo imaging in delayed gadolinium-enhanced MRI (dGEMRIC) at 3 Tesla

The purpose was to evaluate the relative glycosaminoglycan (GAG) content of repair tissue in patients after microfracturing (MFX) and matrix-associated autologous chondrocyte transplantation (MACT) of the knee joint with a dGEMRIC technique based on a newly developed short 3D-GRE sequence with two flip angle excitation pulses. Twenty patients treated with MFX or MACT (ten in each group) were enrolled. For comparability, patients from each group were matched by age (MFX: 37.1 +/- 16.3 years; MACT: 37.4 +/- 8.2 years) and postoperative interval (MFX: 33.0 +/- 17.3 months; MACT: 32.0 +/- 17.2 months). The Delta relaxation rate (DeltaR1) for repair tissue and normal hyaline cartilage and the relative DeltaR1 were calculated, and mean values were compared between both groups using an analysis of variance. The mean DeltaR1 for MFX was 1.07 +/- 0.34 versus 0.32 +/- 0.20 at the intact control site, and for MACT, 1.90 +/- 0.49 compared to 0.87 +/- 0.44, which resulted in a relative DeltaR1 of 3.39 for MFX and 2.18 for MACT. The difference between the cartilage repair groups was statistically significant. The new dGEMRIC technique based on dual flip angle excitation pulses showed higher GAG content in patients after MACT compared to MFX at the same postoperative interval and allowed reducing the data acquisition time to 4 min.

Evaluation and comparison of cartilage repair tissue of the patella and medial femoral condyle by using morphological MRI and biochemical zonal T2 mapping

The objective of this study was to use advanced MR techniques to evaluate and compare cartilage repair tissue after matrix-associated autologous chondrocyte transplantation (MACT) in the patella and medial femoral condyle (MFC). Thirty-four patients treated with MACT underwent 3-T MRI of the knee. Patients were treated on either patella (n = 17) or MFC (n = 17) cartilage and were matched by age and postoperative interval. For morphological evaluation, the MR observation of cartilage repair tissue (MOCART) score was used, with a 3D-True-FISP sequence. For biochemical assessment, T2 mapping was prepared by using a multiecho spin-echo approach with particular attention to the cartilage zonal structure. Statistical evaluation was done by analyses of variance. The MOCART score showed no significant differences between the patella and MFC (p > or = 0.05). With regard to biochemical T2 relaxation, higher T2 values were found throughout the MFC (p < 0.05). The zonal increase in T2 values from deep to superficial was significant for control cartilage (p < 0.001) and cartilage repair tissue (p < 0.05), with an earlier onset in the repair tissue of the patella. The assessment of cartilage repair tissue of the patella and MFC afforded comparable morphological results, whereas biochemical T2 values showed differences, possibly due to dissimilar biomechanical loading conditions.

The clinical and structural long-term results of open repair of massive tears of the rotator cuff

BACKGROUND: At a mean follow-up of 3.1 years, twenty-seven consecutive repairs of massive rotator cuff tears yielded good and excellent clinical results despite a retear rate of 37%. Patients with a retear had improvement over the preoperative state, but those with a structurally intact repair had a substantially better result. The purpose of this study was to reassess the same patients to determine the long-term functional and structural results. METHODS: At a mean follow-up interval of 9.9 years, twenty-three of the twenty-seven patients returned for a review and were examined clinically, radiographically, and with magnetic resonance imaging with use of a methodology identical to that used at 3.1 years. RESULTS: Twenty-two of the twenty-three patients remained very satisfied or satisfied with the result. The mean subjective shoulder value was 82% (compared with 80% at 3.1 years). The mean relative Constant score was 85% (compared with 83% at 3.1 years). The retear rate was 57% at 9.9 years (compared with 37% at 3.1 years; p = 0.168). Patients with an intact repair had a better result than those with a failed reconstruction with respect to the mean absolute Constant score (81 compared with 64 points, respectively; p = 0.015), mean relative Constant score (95% and 77%; p = 0.002), and mean strength of abduction (5.5 and 2.6 kg; p = 0.007). The mean retear size had increased from 882 to 1164 mm(2) (p = 0.016). Supraspinatus and infraspinatus muscle fatty infiltration had increased (p = 0.004 and 0.008, respectively). Muscles with torn tendons preoperatively showed more fatty infiltration than muscles with intact tendons preoperatively, regardless of repair integrity. Shoulders with a retear had a significantly higher mean acromion index than those without retear (0.75 and 0.65, respectively; p = 0.004). CONCLUSIONS: Open repair of massive rotator cuff tears yielded clinically durable, excellent results with high patient satisfaction at a mean of almost ten years postoperatively. Conversely, fatty muscle infiltration of the supraspinatus and infraspinatus progressed, and the retear size increased over time. The preoperative integrity of the tendon appeared to be protective against muscle deterioration. A wide lateral extension of the acromion was identified as a previously unknown risk factor for retearing.

Coupling of mutated Met variants to DNA repair via Abl and Rad51

Abnormal activation of DNA repair pathways by deregulated signaling of receptor tyrosine kinase systems is a compelling likelihood with significant implications in both cancer biology and treatment. Here, we show that due to a potential substrate switch, mutated variants of the receptor for hepatocyte growth factor Met, but not the wild-type form of the receptor, directly couple to the Abl tyrosine kinase and the Rad51 recombinase, two key signaling elements of homologous recombination-based DNA repair. Treatment of cells that express the mutated receptor variants with the Met inhibitor SU11274 leads, in a mutant-dependent manner, to a reduction of tyrosine phosphorylated levels of Abl and Rad51, impairs radiation-induced nuclear translocation of Rad51, and acts as a radiosensitizer together with the p53 inhibitor pifithrin-alpha by increasing cellular double-strand DNA break levels following exposure to ionizing radiation. Finally, we propose that in order to overcome a mutation-dependent resistance to SU11274, this aberrant molecular axis may alternatively be targeted with the Abl inhibitor, nilotinib.

Evaluation of surface defect detection in reinforced concrete bridge decks using terrestrial LiDAR

Routine bridge inspections require labor intensive and highly subjective visual interpretation to determine bridge deck surface condition. Light Detection and Ranging (LiDAR) a relatively new class of survey instrument has become a popular and increasingly used technology for providing as-built and inventory data in civil applications. While an increasing number of private and governmental agencies possess terrestrial and mobile LiDAR systems, an understanding of the technology’s capabilities and potential applications continues to evolve. LiDAR is a line-of-sight instrument and as such, care must be taken when establishing scan locations and resolution to allow the capture of data at an adequate resolution for defining features that contribute to the analysis of bridge deck surface condition. Information such as the location, area, and volume of spalling on deck surfaces, undersides, and support columns can be derived from properly collected LiDAR point clouds. The LiDAR point clouds contain information that can provide quantitative surface condition information, resulting in more accurate structural health monitoring. LiDAR scans were collected at three study bridges, each of which displayed a varying degree of degradation. A variety of commercially available analysis tools and an independently developed algorithm written in ArcGIS Python (ArcPy) were used to locate and quantify surface defects such as location, volume, and area of spalls. The results were visual and numerically displayed in a user-friendly web-based decision support tool integrating prior bridge condition metrics for comparison. LiDAR data processing procedures along with strengths and limitations of point clouds for defining features useful for assessing bridge deck condition are discussed. Point cloud density and incidence angle are two attributes that must be managed carefully to ensure data collected are of high quality and useful for bridge condition evaluation. When collected properly to ensure effective evaluation of bridge surface condition, LiDAR data can be analyzed to provide a useful data set from which to derive bridge deck condition information.