Pre‐transplant phospholipase A2 receptor autoantibody concentration is associated with clinically significant recurrence of membranous nephropathy post‐kidney transplantation

Previous studies that have assessed the association of pre‐transplant antiphospholipase A2 receptor autoantibody (PLA2R‐Ab) concentration with a recurrence of membranous nephropathy (rMN) post‐kidney transplant have yielded variable results. We tested 16 consecutive transplant patients with a history of iMN for pre‐transplant PLA2R‐Ab. Enzyme‐linked immunosorbent assay titers (Euroimmun, NJ, USA) >14 RU/mL were considered positive. A receiver operating characteristic (ROC) analysis was performed after combining data from Quintana et al. (n = 21; Transplantation February 2015) to determine a PLA2R‐Ab concentration which could predict rMN. Six of 16 (37%) patients had biopsy‐proven rMN at a median of 3.2 yr post‐transplant. Of these, five of six (83%) had a positive PLA2R‐Ab pre‐transplant with a median of 82 RU/mL (range = 31–1500). The only patient who had rMN with negative PLA2R‐Ab was later diagnosed with B‐cell lymphoma. One hundred percent (n = 10) of patients with no evidence of rMN (median follow‐up = five yr) had negative pre‐transplant PLA2R‐Ab. In a combined ROC analysis (n = 37), a pre‐transplant PLA2R‐Ab > 29 RU/mL predicted rMN with a sensitivity of 85% and a specificity of 92%. Pre‐transplant PLA2R‐Ab could be a useful tool for the prediction of rMN. Patients with rMN in the absence of PLA2R‐Ab should be screened for occult malignancy and/or alternate antigens.     

Differences between the pediatric and adult presentation of fibromuscular dysplasia: results from the US Registry

Background

Fibromuscular dysplasia (FMD) is a non-inflammatory arteriopathy that causes significant morbidity in children.

Methods

The clinical features, presenting symptoms, and vascular beds involved are reviewed in the first 33 patients aged <18 years who are enrolled in the United States Registry for FMD from five registry sites and compared with 999 adult patients from 12 registry sites.

Results

Mean age at diagnosis was 8.4?±?4.8 years (16 days to 17 years). Compared with adults, pediatric FMD occurs in more males (42.4 vs 6 %, p?<?0.001). Children with FMD have a stronger previous history of hypertension (93.9 vs 69.9 %, p?=?0.002). Hypertension (100 %), headache (55 %), and abdominal bruits (10.7 %) were the most common presenting signs and symptoms. FMD affects renal vasculature in almost all children (97 vs 69.7 %, p?=?0.003). The extra-cranial carotid vessels are less commonly involved in children (23.1 vs 73.3 %, p?<?0.001). The mesenteric arteries (38.9 vs 16.2 %, p?=?0.02) and aorta (26.3 vs 2.4 %, p?<?0.001) are more commonly involved in children.

Conclusions

In the United States Registry for FMD, pediatric FMD affects children from infancy throughout childhood. All children presented with hypertension and many presented with headache and abdominal bruits. In children, FMD most commonly affects the renal vasculature, but also frequently involves the mesenteric arteries and abdominal aorta; the carotid vessels are less frequently involved.

     

The Impact of Deep Sternal Wound Infection on Mortality and Resource Utilization: A Population-based Study

Background

Recent national infection control efforts have been directed at reducing postsurgical infection rates, related morbidity, and cost. We sought to evaluate population-level rates of deep sternal wound infection (DSWI) after cardiac surgery, associated mortality, and resource use compared to patients undergoing cardiac surgery without postoperative DSWI relative to historical trends.

Methods

We analyzed the MarketScan ^® Commercial Claims Databases from 2009 to 2013 to identify adult patients who developed DSWI after open cardiac surgery. Patients with and without DSWI were compared. The outcomes of interest included 30-day, 90-day, and 1-year in-hospital mortality. Utilization outcomes, including total hospital days and inpatient costs, were calculated in the time period from the index cardiac surgery through 90 days after DSWI diagnosis.

Results

In this cohort, 176,537 patients underwent one or more cardiac surgery procedures. DSWI occurred in 2835 (1.6 %) patients. One-year mortality for patients with DSWI was 10.7 versus 2.5 % (P < 0.001) in patients without DSWI. Mean hospital days in patients with DSWI were 33 versus 9 days for patients without DSWI (P < 0.001). Mean cost for patients with DSWI was greater than 2.5 times that of patients without DSWI ($211,478 vs $82,089, P < 0.001).

Conclusions

Treatment of DSWI results in substantial morbidity, mortality, and excess cost for treating facilities. The rates of DSWI have not decreased dramatically over the last 10–20 years. Thus, more attention needs to be focused toward understanding treatment variation that exists in patients diagnosed with DSWI.

     

Evaluation of stair motion contributes to new insights into hip osteoarthritis‐related motion pathomechanics

Stair motion in the presence of hip osteoarthritis (OA) has received less attention than level walking. Its more strenuous aspect may shed the light on different locomotor strategies when compared to walking. We, therefore, aimed to define stair motion features associated to hip OA and to evaluate whether these specific features would differ from level walking and better characterize the hip pathological condition. Principal component and linear discriminant analyses were, respectively, used as data reduction and classification techniques. Our study highlighted that most of stair motion features associated to hip OA were similar to the ones of walking. Stair descent presented with the lowest misclassification error rate, ranging from 12% to 19% (estimated by cross‐validation). But, features that may be considered as a mechanism to reduce demand on the hip abductors were found to be more important in the stair ascent condition. This was reflected by both, greater importance in the classification rule and variance compared with walking, that is, decreased hip internal rotation moment at mid‐stance (72.50% vs. 57.63%) and increased trunk lateroflexion toward affected side (56.43% vs. 29.37%). This study emphasized the importance of investigating stair motion in hip osteoarthritic population by highlighting specific locomotor strategies. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:187–196, 2016.     

Subject‐specific modeling of muscle force and knee contact in total knee arthroplasty

Understanding the mechanical loading environment and resulting joint mechanics for activities of daily living in total knee arthroplasty is essential to continuous improvement in implant design. Although survivorship of these devices is good, a substantial number of patients report dissatisfaction with the outcome of their procedure. Knowledge of in vivo kinematics and joint loading will enable improvement in preclinical assessment and refinement of implant geometry. The purpose of this investigation was to describe the mechanics of total knee arthroplasty during a variety of activities of daily living (gait, walking down stairs, and chair rise/sit). Estimates of muscle forces, tibial contact load, location, and pressure distribution was performed through a combination of mobile fluoroscopy data collection, musculoskeletal modeling, and finite element simulation. For the activities evaluated, joint compressive load was greatest during walking down stairs; however, the highest contact pressure occurred during chair rise/sit. The joint contact moment in the frontal plane was mainly varus for gait and walking down stairs, while it was valgus during chair rise/sit. Excursion of the center of pressure on the tibial component was similar during each activity and between the medial and lateral sides. The main determinants of center of pressure location were internal–external rotation, joint load, and tibial insert conformity. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1576–1587, 2016.