Comparative evaluation of a heparin‐citrate anticoagulation for LDL‐apheresis in two primary apheresis systems

BACKGROUND: As COBE Spectra has been replaced in many parts of the world, we describe a new protocol for low‐density lipoprotein (LDL)‐apheresis performed on familial hypercholesterolemia patients for the Spectra Optia platform. METHODS: For all procedures, after administering a bolus of heparin of 2,500 U, 10,000 U of heparin added to a 600 ml ACD‐A bag was used as anticoagulant (AC). In a first phase (A), 16 apheresis procedures with COBE Spectra using an inlet:AC ratio of 25:1 were compared to 18 LDL‐apheresis treatments with Spectra Optia at split Inlet:AC ratios of 16:1/18:1 or 20:1/25:1. Platelet activation and coagulation markers were assessed. In a follow‐up phase (B), 20 procedures on Spectra Optia using an inlet:AC ratio of 20:1 were performed. RESULTS: Although coagulation markers and platelet activation analyzed were similar in both apheresis devices used, COBE Spectra procedures did not show any visual clumping in the sets. Visual analysis of clumping was highest in the Spectra Optia's 20:1/25:1 AC regimen (5/8 procedures). For the lowest Spectra Optia, AC regimen and during the follow‐up phase reversible clump formation in the disposable set was similar (1/10 procedures). Clumping was successfully reversed in all cases by temporarily lowering the inlet:AC ratio to 18:1. Blood cell counts (WBC, Plt, Hct) were similar for both COBE Spectra and Spectra Optia procedures. Spectra Optia had a significantly higher plasma removal efficiency versus COBE Spectra (84% vs.75%, P < .05). No serious adverse events were observed. CONCLUSION: Apheresis procedures on the Spectra Optia system with low‐dose heparin‐citrate anticoagulation are feasible and safe.     

Acute Median Neuropathy and Carpal Tunnel Release in Perilunate Injuries Can We Predict Who Gets a Median Neuropathy?

This study addressed the following null hypotheses: 1) There are no demographic differences between patients with perilunate dislocation (PLD) or fracture-dislocation (PLFD); 2) There are no factors associated with the development of median nerve symptoms in the setting of a PLD or PLFD; and 3) There are no factors associated with carpal tunnel release. Using a retrospective search of a prospective trauma database, we identified all patients who had sustained a radiologically confirmed PLD or PLFD over a 10-year period at two trauma centers. From the medical records we identified median nerve symptoms and carpal tunnel release in addition to demographic and injury characteristics. Among the 71 patients treated for PLD or PLFD, acute median neuropathy was diagnosed in 33 patients (47 %). The only significant difference between PLD and PLFD was a younger age with PLFD. No demographic or injury factors were associated with symptoms of median neuropathy. Carpal tunnel release surgery during the initial operative management was related to the presence of median nerve symptoms and the trauma center. We report a high incidence of acute median neuropathy accompanying perilunate injuries. As there are no demographic or injury factors associated with symptoms of median neuropathy; all patients with PLD/PLFD merit equally high vigilance for acute median neuropathy.Level of Evidence: Level III, prognostic study     

Acoustic characterization of a miniature matrix transducer for pediatric 3D transesophageal echocardiography

This paper presents the design, fabrication and characterization of a miniature PZT-on-CMOS matrix transducer for real-time pediatric 3-dimensional (3D) transesophageal echocardiography (TEE). This 3D TEE probe consists of a 32?×?32 array of PZT elements integrated on top of an Application Specific Integrated Circuit (ASIC). We propose a partitioned transmit/receive array architecture wherein the 8?×?8 transmitter elements, located at the centre of the array, are directly wired out and the remaining receive elements are grouped into 96 sub-arrays of 3?×?3 elements. The echoes received by these sub-groups are locally processed by micro-beamformer circuits in the ASIC that allow pre-steering up to ±37°. The PZT-on-CMOS matrix transducer has been characterized acoustically and has a centre frequency of 5.8 MHz, -6 dB bandwidth of 67%, a transmit efficiency of 6 kPa/V at 30 mm, and a receive dynamic range of 85 dB with minimum and maximum detectable pressures of 5 Pa and 84 kPa respectively. The properties are very suitable for a miniature pediatric real-time 3D TEE probe.     

No effect of additional screw fixation of a cementless,all-polyethylene press-fit socket on migration,wear, and clinical outcome

Background and purpose — Additional screw fixation of the all-polyethylene press-fit RM cup (Mathys) has no additional value for migration, in the first 2 years after surgery. However, the medium-term and long-term effects of screw fixation remain unclear. We therefore evaluated the influence of screw fixation on migration, wear, and clinical outcome at 6.5 years using radiostereometric analysis (RSA).

Patients and methods — This study involved prolonged follow-up from a previous randomized controlled trial (RCT). We analyzed RSA radiographs taken at baseline and at 1-, 2-, and 6.5-year follow-up. Cup migration and wear were assessed using model-based RSA software. Wear was calculated as translation of the femoral head model in relation to the cup model. Total translation, rotation, and wear were calculated mathematically from results of the orthogonal components.

Results — 27 patients (15 with screw fixation and 12 without) were available for follow-up at 6.5 (5.6–7.2) years. Total translation (0.50?mm vs. 0.56?mm) and rotation (1.01 degrees vs. 1.33 degrees) of the cup was low, and was not significantly different between the 2 groups. Wear increased over time, and was similar between the 2 groups (0.58?mm vs. 0.53?mm). Wear rate (0.08?mm/year vs. 0.09?mm/year) and clinical outcomes were also similar.

Interpretation — Our results indicate that additional screw fixation of all-polyethylene press-fit RM cups has no additional value regarding medium-term migration and clinical outcome. The wear rate was low in both groups.