Background Detailed knowledge of the dimensions and shape of the main arteries of the body and how they change with age and disease is important for understanding arterial pathophysiology and improving minimally invasive devices to treat arterial diseases. Our goal was to describe and compare geometric remodeling of the aorta and peripheral arteries in the context of patient demographics and cardiovascular risk factors. Methods 3D reconstructions of Computerized Tomography Angiography scans were performed in n=122 subjects 5-93 years old (mean 47±24 years, 64M/58F). Best-fit arterial diameters, lengths and tortuosity for the principle named arteries in the chest, abdomen, pelvis and upper thigh were measured, and multiple linear regression analysis was performed to examine how these morphological parameters associate with patient demographics and risk factors. Results Large elastic arteries increased their diameter, length and tortuosity with age, while muscular arteries primarily became more tortuous. Demographics and risk factors explained >70% of the variation in diameters of the abdominal aorta, paravisceral aorta, and the aortic arch; and >75% of variation in tortuosity from the profunda femoris to the brachiocephalic artery. Male gender, larger body mass index and hypertension contributed to larger diameters, while presence of diabetes was associated with somewhat straighter arteries. Overall the effects of cardiovascular risk factors on geometric remodeling were small compared to those of demographics. Conclusions The geometry of the vascular tree is significantly affected by aging, demographics and some risk factors. Elastic and muscular arteries remodel differently, possibly due to differences in their microstructure.

Background As primary total hip arthroplasty volume continues to increase, so will the number of revision total hip arthroplasty (rTHA) procedures. These complex cases represent a significant clinical and financial burden to the health-care system. Methods This was a retrospective review using the National Inpatient Sample. International Classification of Diseases, 9th and 10 th revision codes were used to identify patients who underwent rTHA and create cohorts based on rTHA indications from 2012 to 2018. National and regional trends for length of stay (LOS), cost, and discharge location were evaluated. Results A total of 292,250 rTHA procedures were identified. The annual number of rTHA procedures increased by 28.1% from 2012 to 2018 (37,325 to 47,810). The top 3 indications for rTHA were instability (20.4%), aseptic loosening (17.8%), and infection (11.1%). Over the study period, the proportion of patients discharged to skilled nursing facility decreased from 44.2% to 38% ( P < .001). Hospital LOS decreased on average from 4.8 to 4.4 days ( P < .001). Infections had the highest average LOS (7.3 days) followed by periprosthetic fractures (6.5 days). Hospital costs decreased over the study period, from $25,794 to $24,555 ( P < .001). The proportion of rTHA cases performed at urban academic centers increased (58.0% to 75.3%, P < .001) while the proportion performed at urban nonacademic centers decreased (35.5% to 19.4%, P < .001). Conclusion Instability was the most common indication for rTHA between 2012 and 2018. The proportion of rTHA performed in urban academic centers has increased substantially, away from urban nonacademic centers. While cost and LOS have decreased, significant geographic variability exists.

changes, but her recovery was punctuated by the development of a small blood stained pleural effusion. This settled spontaneously and was not associated with any perfusion abnormalities on ventilation-perfusion scanning. She was discharged on the 27th hospital day and she has had no further respiratory or renal problems over the subsequent year.When the acute illness failed to improve rapidly on withdrawal of nitrofurantoin, an open lung biopsy was performed on the second hospital day. This showed pronounced alveolar haemorrhage with focal desquamation but no evidence of vasculitis (fig 2). Renal function remained normal throughout and haematuria was never noted. The serum level of antiglomerular basement membrane antibody was 7 3% (normal range < 12%) and bacterial and viral cultures of lung tissue were sterile. Pulmonary function testing on the 14th hospital day showed a restrictive ventilatory defect, with vital capacity (VC) 175 litre (54% predicted), FEVI/VC ratio 80%, and transfer coefficient (Kco) 2 3 (normal range 1 09-3 05 mmol min-kPa-'1 l'). Subsequent chest radiographs and pulmonary function tests have shown a gradual but complete recovery to normal, the latest VC being 2 65 1 (83% predicted), total lung capacity 3-98 1 (94% predicted), and Kco 1 8. The results of a nutritional screen on the 11th hospital day, at the time the patient was being weaned from ventilation, included normal vitamin E concentrations; a dietary history revealed a high intake of saturated fats.

No abstract

The medical device industry has grown substantially in recent years. There is limited research examining orthopedic subspecialties and the recall of orthopedic devices. We hypothesize that knee arthroplasty devices cleared through the Food and Drug Administration (FDA) 510(k)-notification process would have a higher recall rate than the premarket approval (PMA) process. Methods The FDA database was thoroughly queried for all knee arthroplasty surgical devices from January 1, 2007 through December 31, 2017. Recalled devices were analyzed by manufacturer, type of implant, recall class, manufacturer-determined reason, FDA-determined reason, quantity affected, submission type, and distribution within the United States or internationally. Results Out of over 30,000 medical devices on the market, a total of 300 knee arthroplasty devices from 18 different companies were recalled during the time frame of this study. Tibial components accounted for 35.33% of devices, polyethylene implants for 38.67%, and femoral components for 15%. The most common reason for recall was device design (n = 134, 44.67%), followed by process control (n = 32, 10.67%). Of the 300 knee arthroplasty devices recalled, 267 (89.0%) were cleared through the 510(k) premarket notification process and 33 (11.0%) devices were approved through the PMA process. Conclusions A larger proportion of knee arthroplasty surgical devices cleared through the 510(k) process were recalled compared to implants approved through the stricter PMA process. Changing the 510(k) process may enable manufacturers to improve upon the safety of their devices.