Frequency and Clinical Impact of Platelet Factor 4-Specific Antibodies in Patients Undergoing Extracorporeal Membrane Oxygenation.

INTRODUCTION/OBJECTIVES: Extracorporeal membrane oxygenation (ECMO) provides circulatory support in patients with severe heart failure, but the frequent use of unfractionated heparin exposes patients to high risk of heparin-induced thrombocytopenia (HIT). We prospectively evaluated the development and clinical impact of platelet factor 4 (PF4)-specific antibodies (Abs) during ECMO and whether specific biological characteristics could predict HIT. MATERIALS AND METHODS: From 2014 to 2018, we studied 57 adults who underwent an ECMO for at least 5 days. The plasma samples collected daily were tested for PF4-specific Abs using immunoassays to detect immunoglobulin (Ig) G, A, and M isotypes or only IgG. Serotonin release assay was performed without and with PF4 to detect pathogenic Abs. RESULTS: Twenty-nine patients (50%) were positive for PF4-specific Abs (IgG, A, M), with IgG in 17/57 (30%) and 16 of them (94%) were immunized within 10 days. PF4-specific IgG Abs did not affect the clinical or biological course of most patients. HIT was suspected in only two patients with ECMO circuit dysfunction and unexpected platelet count decrease after day 5. High levels of PF4-specific IgG were detected in both patients, and HIT was confirmed by a serotonin release assay, which was also more sensitive when exogenous PF4 was present. CONCLUSION: PF4-specific Abs are common during ECMO but are mostly non-pathogenic and not associated with a less favorable prognosis. However, an abnormal platelet count evolution, in particular if associated with ECMO circuit dysfunction, should prompt the search for pathogenic PF4-specific IgG.

Long-term follow-up on high-rate cut-off programming for implantable cardioverter defibrillators in primary prevention patients with left ventricular systolic dysfunction.

AIMS: Implantable cardioverter defibrillators (ICDs) are efficient in reducing mortality in patients with left ventricular systolic dysfunction. High-rate cut-off programming may be effective in reducing appropriate and inappropriate therapies, but as the long-term consequences on morbidity and mortality remain unclear, it is underutilized. METHODS AND RESULTS: We prospectively studied 365 consecutive patients (mean age 60 ± 10 years), with ischaemic (63%) or non-ischaemic cardiomyopathy and left ventricular dysfunction (mean ejection fraction 25 ± 7%), who were implanted with an ICD in primary prevention of sudden cardiac death (41% single chamber, 31% dual chamber, and 28% biventricular). All devices were programmed with a shock-only zone over 220 beats per minute (b.p.m.) and a monitoring zone between 170 and 220 b.p.m. During a median follow-up of 40 months, 41 patients received appropriate shocks (11.2%) and 24 inappropriate shocks (6.6%). Then, 306 patients never experienced any ICD shock (84%). Inappropriate discharges were related to supraventricular tachyarrhythmia in 10 patients, and noise/oversensing in 14 patients. Ventricular tachycardia episodes, sustained or not, were recorded in the monitoring zone in 43 patients (11.8%). Seven of these patients were symptomatic (1.9%), without lethal consequence. Sixty-two patients (17%) died: 35 from end-stage heart failure, 1 from unexplained sudden death, and 26 from a documented non-cardiac cause. CONCLUSION: High-rate cut-off (220 b.p.m.) shock-only ICD programming, in primary prevention patients with reduced left ventricular ejection fraction, appeared to be safe during a long-term follow-up. It also resulted in a very low rate of discharges, which are known to be deleterious in this population.

Left retropectoral axillary implantation of defibrillators in young women.

We propose a complete surgical approach by left retropectoral transaxillary implantation with no vein puncture to improve the aesthetic and psychological tolerance of the implantable cardioverter defibrillator and avoid the pneumothorax and the subclavian crush syndrome.

Kinetic analysis of cooking losses from beef and other animal muscles heated in a water bath--effect of sample dimensions and prior freezing and ageing.

Cooking loss kinetics were measured on cubes and parallelepipeds of beef Semimembranosus muscle ranging from 1 cm × 1 cm × 1 cm to 7 cm × 7 cm × 28 cm in size. The samples were water bath-heated at three different temperatures, i.e. 50°C, 70°C and 90°C, and for five different times. Temperatures were simulated to help interpret the results. Pre-freezing the sample, difference in ageing time, and in muscle fiber orientation had little influence on cooking losses. At longer treatment times, the effects of sample size disappeared and cooking losses depended only on the temperature. A selection of the tests was repeated on four other beef muscles and on veal, horse and lamb Semimembranosus muscle. Kinetics followed similar curves in all cases but resulted in different final water contents. The shape of the kinetics curves suggests first-order kinetics.