Evaluation of systemic inflammation in response to remote ischemic preconditioning in patients undergoing transcatheter aortic valve replacement (TAVR).

BACKGROUND: Systemic inflammation can occur after transcatheter aortic valve replacement (TAVR) and correlates with adverse outcome. The impact of remote ischemic preconditioning (RIPC) on TAVR associated systemic inflammation is unknown and was focus of this study. METHODS: We performed a prospective controlled trial at a single center and included 66 patients treated with remote ischemic preconditioning (RIPC) prior to TAVR, who were matched to a control group by propensity score. RIPC was applied to the upper extremity using a conventional tourniquet. Definition of systemic inflammation was based on leucocyte count, C-reactive protein (CRP), procalcitonin (PCT) and interleukin-6 (IL-6), assessed in the first 5 days following the TAVR procedure. Mortality was determined within 6 months after TAVR. RIPC group and matched control group showed comparable baseline characteristics. RESULTS: Systemic inflammation occurred in 66% of all patients after TAVR. Overall, survival after 6 months was significantly reduced in patients with systemic inflammation. RIPC, in comparison to control, did not significantly alter the plasma levels of leucocyte count, CRP, PCT or IL-6 within the first 5 days after TAVR. Furthermore, inflammation associated survival after 6 months was not improved by RIPC. Of all peri-interventional variables assessed, only the amount of the applied contrast agent was connected to the occurrence of systemic inflammation. CONCLUSIONS: Systemic inflammation frequently occurs after TAVR and leads to increased mortality after 6 months. RIPC neither reduces the incidence of systemic inflammation nor improves inflammation associated patient survival within 6 months.

Electromagnetic Interference from Heated Gloves May Compromise Avalanche Transceiver Function.

INTRODUCTION: Rapid location of avalanche victims by companions using avalanche transceivers is of utmost importance to prevent asphyxiation. The objective was to determine whether electromagnetic interference from heating elements in gloves worn by rescuers or victims can impair the receiving or transmitting function of avalanche beacons. METHODS: Commercially available heated gloves from 3 different manufacturers were examined during a simulated search with 3 common brands of avalanche transceivers. Distance to target beacon at first signal detection and accuracy of direction to target, as indicated by the arrow from the direction indicator, were evaluated. RESULTS: Preliminary tests showed that transmitting and receiving signals are degraded by electromagnetic interference caused by rectangular pulses emitted by activated heating elements. Field tests revealed significantly reduced distances of first signal detection when heated gloves were turned on near receiving avalanche transceivers (P<0.001; Wilcoxon signed-rank test). Decreased distance to target beacon ranged between 1.9 m (5%) and 41.5 m (94%) at first detection, depending on the avalanche transceiver used. CONCLUSIONS: Avalanche transceivers are susceptible to electromagnetic interference from gloves with electric heating elements. We do not recommend using heated gloves when performing a transceiver search for avalanche victims because it can lead to a delay in rescue.

Remote Ischemic Preconditioning Neither Improves Survival nor Reduces Myocardial or Kidney Injury in Patients Undergoing Transcatheter Aortic Valve Implantation (TAVI).

BACKGROUND: Peri-interventional myocardial injury occurs frequently during transcatheter aortic valve implantation (TAVI). We assessed the effect of remote ischemic preconditioning (RIPC) on myocardial injury, acute kidney injury (AKIN) and 6-month mortality in patients undergoing TAVI. METHODS: We performed a prospective single-center controlled trial. Sixty-six patients treated with RIPC prior to TAVI were enrolled in the study and were matched to a control group by propensity-score. RIPC was applied to the upper extremity using a conventional tourniquet. Myocardial injury was assessed using high-sensitive troponin-T (hsTnT), and kidney injury was assessed using serum creatinine levels. Data were compared with the Wilcoxon-Rank and McNemar tests. Mortality was analysed with the log-rank test. RESULTS: TAVI led to a significant rise of hsTnT across all patients (p < 0.001). No significant inter-group difference in maximum troponin release or areas-under-the-curve was detected. Medtronic CoreValve and Edwards Sapien valves showed similar peri-interventional troponin kinetics and patients receiving neither valve did benefit from RIPC. AKIN occurred in one RIPC patient and four non-RIPC patients (p = 0.250). No significant difference in 6-month mortality was observed. No adverse events related to RIPC were recorded. CONCLUSION: Our data do not show a beneficial role of RIPC in TAVI patients for cardio- or renoprotection, or improved survival.