Assessments of right ventricular strain using cardiac magnetic resonance imaging following kidney transplantation.

Although kidney transplantation (KT) has been shown to ameliorate adverse left ventricular (LV) remodelling associated with end stage kidney disease, its effects on the right ventricle have not been well studied. Recently, strain imaging has been shown to be a sensitive measure of early subclinical myocardial dysfunction. Using cardiac magnetic resonance imaging (MRI), we examined the effects of KT on right ventricular (RV) strain parameters. In a cohort of 81 patients (39 patients underwent KT and 42 patients remained on dialysis as control group), cardiac MRI studies were obtained at baseline and at 1 year follow-up. There were no significant differences in RV strain values between the groups at baseline. After 1 year, RV strain values did not significantly change in patients who received KT, and changes in RV strain over 1 year were not significantly different between the KT and the dialysis groups. Given the previously demonstrated improvement in LV strain post-KT, the current study suggests that RV and LV remodelling post-KT may have different mechanisms. Further studies elucidating the effects of KT on RV remodelling are needed.

Systematic Interrogation of Angiogenesis in the Ischemic Mouse Hind Limb: Vulnerabilities and Quality Assurance.

OBJECTIVE: There has been little success in translating preclinical studies of mouse hind limb ischemia into benefit for patients with peripheral artery disease. Using systematic strategies, we sought to define the injury and angiogenesis landscapes in mice subjected to hind limb ischemia and ascertain whether published studies to date have used an analysis strategy concordant with these data. Approach and Results: Maps of ischemic injury were generated from 22 different hind limb muscles and 33 muscle territories in 12-week-old C57BL/6 mice, based on loss or centralization of myofiber nuclei. Angiogenesis was similarly mapped based on CD (cluster of differentiation) 31-positive capillary content. Only 10 of 33 muscle territories displayed consistent muscle injury, with the distal anterior hind limb muscles most reliably injured. Angiogenesis was patchy and exclusively associated with zones of regenerated muscle (central nuclei). Angiogenesis was not observed in normal appearing muscle, necrotic muscle, or injury border zones. Systematic review of mouse hind limb angiogenesis studies identified 5147 unique publications, of which 509 met eligibility criteria for analysis. Only 7% of these analyzed manuscripts evaluated angiogenesis in distal anterior hind limb muscles and only 15% consistently examined for angiogenesis in zones of muscle regeneration. CONCLUSIONS: In 12-week C57BL/6 mice, angiogenesis postfemoral artery excision proceeds exclusively in zones of muscle regeneration. Only a minority of studies to date have analyzed angiogenesis in regions of demonstrably regenerating muscle or in high-likelihood territories. Quality assurance standards, informed by the atlas and mapping data herein, could augment data reliability and potentially help translate mouse hind limb ischemia studies to patient care.

A sticky situation: myocardial infarction in a young woman with immune thrombocytopenia on eltrombopag and a history of mediastinal radiation.

More recent immune thrombocytopenia (ITP) treatment strategies enhance platelet production with the use of thrombopoietin receptor agonists (TPO-RA) such as eltrombopag. Patients receiving TPO-RA agents may be at an increased risk of thromboembolism, however the pathophysiology and common underlying risk factors are not well understood. We present the case of a young asplenic woman on eltrombopag for chronic ITP with acute myocardial infarction involving the right coronary artery. Past medical history was significant for remote mediastinal radiation for lymphoma and splenectomy for ITP. She had no other risk factors for coronary artery disease. She underwent coronary catheterization and balloon angioplasty to the culprit lesion, although stenting was deferred due to concerns with dual antiplatelet therapy. She was discharged from hospital on single antiplatelet therapy with acetylsalicylic acid. We believe that the patient's ITP, recent eltrombopag use, surgical asplenia and history of mediastinal radiation synergistically contributed to her myocardial infarction. The risks of bleeding and thromboembolism must be carefully weighed in patients receiving TPO-RA therapy.

Staphylococcus pettenkoferi bacteremia: A case report and review of the literature.

Staphylococcus pettenkoferi is a relatively recently described coagulase-negative staphylococci species first described in 2002. Since then, nine additional cases of infection caused by this species have been reported in various countries around the world, including Germany, Belgium, France, South Korea, Italy, Brazil and Mexico. The present report describes a case of S pettenkoferi peripheral line-associated bacteremia. To our knowledge, the present report is the first description of human infection caused by S pettenkoferi in Canada. The present report also provides an overview of the laboratory detection of uncommon coagulase-negative staphylococci.

Le Staphylococcus pettenkoferi est une espèce de staphylocoque à coagulase négative qui a été décrit pour la première fois en 2002. Depuis, neuf autres cas d'infections causées par cette espèce ont été signalés dans divers pays du monde, y compris l'Allemagne, la Belgique, la France, la Corée du Sud, l'Italie, le Brésil et le Mexique. Le présent rapport décrit un cas de bactériémie à S pettenkoferi associée à un cathéter périphérique. En autant que les auteurs le sachent, il s'agit du premier rapport d'infection humaine à S pettenkoferi au Canada, qui donne également un aperçu de la détection en laboratoire de staphylocoques à coagulase négative rares.

Cardiac MRI assessment of the right ventricle pre-and post-kidney transplant.

Worsening renal function in chronic kidney disease correlates with worsening right ventricular (RV) systolic function. We evaluated the association between kidney transplantation (KT) and RV structure and systolic function, and the relationships between RV and left ventricular (LV) changes, blood pressure, and specific cardiac biomarkers, in patients with end-stage kidney disease using cardiac magnetic resonance imaging (CMR). In this prospective, multi-centre, cohort study, 39 adult patients on dialysis receiving KT and 42 patients eligible for, but not yet receiving KT, were recruited. CMR was performed at baseline, and repeated at 12 months. Among 81 patients (mean age 51 years, 30% female), RV end-diastolic volume index (RVEDVi), end-systolic volume index (RVESVi), mass index (RVMi), and ejection fraction (RVEF) did not change significantly within either the dialysis or KT group over 12 months (all p ≥ 0.10). There were no significant differences in the 12-month changes of these parameters between the dialysis and KT groups (all p ≥ 0.10). RVMI demonstrated positive correlations with NT-proBNP and systolic blood pressure, but not GDF-15, at baseline and at 12 months. Changes in RVEDVi, RVESVi, and RVEF were positively correlated with changes in LVEDVi, LVESVi, and LVEF, respectively over 12 months (Spearman r = 0.72, 0.52, and 0.41; all p < 0.001), but not mass index (Spearman r = 0.20, p = 0.078). In conclusion, there were no significant changes in RV mass, volumes, or systolic function 12 months after KT, as compared with continuation of dialysis. The associations between RV and LV remodeling may suggest similar underlying pathophysiologic mechanisms.