Retrospective Review of Time to Uterotonic Administration and Maternal Outcomes After Postpartum Hemorrhage.

OBJECTIVE: Despite advances in health care and ample resources, post-partum hemorrhage (PPH) rates are increasing in high income countries. Although guidelines recommend therapeutic uterotonics, timing of administration is open to judgement and most often based on (inherently inaccurate) visual estimates of blood loss. With severe hemorrhage, every minute of delay can have significant consequences. Our objective was to examine the timing of uterotonic administration and its impact upon maternal outcomes. We hypothesized that increased time to uterotonic administration following the identification of PPH would be associated with a greater decline in hemoglobin (Hb) and higher odds of hypotension and transfusion. METHODS: We reviewed all cases of PPH that occurred at an academic centre between June 2015 and September 2017. All cases of primary PPH (i.e., those declared within 24 h of delivery with estimated blood loss [EBL] >500 mL for vaginal and >1000 mL for cesarean deliveries) were analyzed. Patient records were excluded if they were missing information regarding time of PPH declaration, uterotonic administration, and/or Hb measures, or if a pre-existing medical condition could have contributed to PPH. RESULTS: Of 4397 births, there were 259 (5.9%) cases of primary PPH, of which 128 were included in this analysis. For these patients, each 5-minute delay in uterotonic treatment was associated with 26% higher odds of hypotension following delivery of any type. For vaginal deliveries (n = 86), each 5-minute delay was associated with 31% and 34% higher odds of hypotension and transfusion, respectively. CONCLUSION: In this study, delay in administration of therapeutic uterotonics was associated with a higher incidence of hypotension and transfusion in primary PPH patients.

Extended thromboprophylaxis following major abdominal/pelvic cancer-related surgery: A systematic review and meta-analysis of the literature.

BACKGROUND: Postoperative venous thromboembolism (VTE) is a significant source of morbidity and mortality in cancer patients undergoing major abdominopelvic surgery. Many guidelines recommend the use of extended duration postoperative low molecular weight heparin (LMWH) thromboprophylaxis, although the evidence for its overall safety and efficacy is unclear. AIMS: We sought to assess the 30-day postoperative rates of VTE and bleeding complications following major abdominopelvic cancer surgery and to explore the potential risks and benefits of extended duration thromboprophylaxis with LMWH in such setting. METHODS: A systematic search of the literature was conducted. Observational studies and RCTs of adult patients that underwent abdominopelvic cancer surgery were included. Pooled proportions for the outcome measures and pooled relative risks for the extended duration thromboprophylaxis analyses were generated. RESULTS: A total of 68 studies (1,631,118 patients) were included in the analysis. The 30-day postoperative rate of VTE was 1.7% (95%CI: 1.5 to 1.9, I2 = 98%). The postoperative rate of clinically-relevant bleeding complications was 3.5% (95%CI: 1.6 to 6.1, I2 = 99%). Extended duration thromboprophylaxis was associated with a significant reduction in the incidence of clinical VTE (1.0% vs 2.1%; Risk ratio (RR) 0.48, 95%CI: 0.31 to 0.74; I2 = 0), without a significant increase in clinically-relevant bleeding (4.0% vs. 4.9%; RR 1.0, 95%CI: 0.66 to 1.5, I2 = 0). CONCLUSIONS: The overall risk of symptomatic VTE within 30 days of surgery was relatively low. Extended LMWH thromboprophylaxis following major abdominopelvic cancer surgery was associated with a reduced incidence of clinical VTE without an increase in clinically-relevant bleeding.

Safety and efficacy of apixaban thromboprophylaxis in cancer patients with metastatic disease: A post-hoc analysis of the AVERT trial.

BACKGROUND: The risk of venous thromboembolism (VTE) is increased in patients with active cancer and the risk is highest in those with metastatic disease. The risks and benefits of thromboprophylaxis among cancer patients with metastatic disease initiating chemotherapy treatment are unknown. To address this important knowledge gap, we evaluated the efficacy and safety of apixaban thromboprophylaxis in patients with and without metastatic disease. METHODS: Post-hoc analysis of the AVERT trial, which was a randomized, placebo-controlled, double-blind trial comparing apixaban therapy to placebo for VTE prophylaxis among cancer patients who were intermediate-to-high risk for VTE and who were initiating chemotherapy. The hazards ratios (HRs) for VTE and major bleeding episodes in patients with and without metastatic disease were calculated using a Cox regression model controlling for age, gender, and center. RESULTS: A total of 574 patients underwent randomization and 365 patients could be stratified according to the presence (n = 138) or absence (n = 227) of metastatic disease. In patients with metastatic disease, those receiving apixaban had a significantly lower risk of VTE (HR 0.55; 95% CI 0.32 to 0.97) without a significant increase in major bleeding complications (HR 1.36 95% CI 0.27 to 6.93) compared to those on placebo. In patients without metastatic disease, the use of apixaban was also associated with a significantly lower risk of VTE (HR 0.34 95% CI 0.19 to 0.60) without a significant increase in major bleeding complications (HR 1.14 95% CI 0.08 to 15.91). CONCLUSIONS: In patients with and without metastatic disease, apixaban thromboprophylaxis was associated with a significantly lower rate of VTE compared to placebo.

Receptor-Ligand Interaction Mediates Targeting of Endothelial Colony Forming Cell-derived Exosomes to the Kidney after Ischemic Injury.

Endothelial colony forming cell (ECFC)-derived exosomes protect mice against ischemic kidney injury, via transfer of microRNA-(miR)-486-5p. Mechanisms mediating exosome recruitment to tissues are unclear. We hypothesized that ECFC exosomes target ischemic kidneys, involving interaction between exosomal CXC chemokine receptor type 4 (CXCR4) and stromal cell-derived factor (SDF)-1α. Ischemia-reperfusion was induced in mice by bilateral renal vascular clamp, with intravenous infusion of exosomes at reperfusion. Optical imaging determined exosome biodistribution, and miR-486-5p was measured by real-time PCR. Human umbilical vein endothelial cells (HUVECs) were cultured to study the CXCR4/SDF-1α interaction. Targeting of administered exosomes to ischemic kidneys was detected 30 min and 4 hrs after reperfusion. Exosomes increased miR-486-5p levels only in kidneys, within proximal tubules, glomeruli, and endothelial cells. Uptake of fluorescently-labeled exosomes into HUVECs, and exosomal transfer of miR-486-5p were enhanced by hypoxia, effects blocked by neutralizing antibody to SDF-1α or by the CXCR4 inhibitor plerixafor. Infusion of ECFC exosomes prevented ischemic kidney injury in vivo, an effect that was not observed when exosomes were pre-incubated with plerixafor. These data indicate that ECFC exosomes selectively target the kidneys after ischemic injury, with rapid cellular transfer of miR486-5p. Targeting of exosomes may involve interaction of CXCR4 with endothelial cell SDF-1α.

Transfer of microRNA-486-5p from human endothelial colony forming cell-derived exosomes reduces ischemic kidney injury.

Administration of human cord blood endothelial colony-forming cells (ECFCs) or their exosomes protects mice against kidney ischemia/reperfusion injury. Here we studied the microRNA (miRNA) content of ECFC exosomes and the role of miRNA transfer in kidney and endothelial cell protection. ECFC exosomes were enriched in miR-486-5p, which targets the phosphatase and tensin homolog (PTEN) and the Akt pathway. In cultured endothelial cells exposed to hypoxia, incubation with ECFC exosomes increased miR-486-5p, decreased PTEN, and stimulated Akt phosphorylation. Exposure of hypoxic endothelial cells to conditioned medium from ECFCs pretreated with anti-miR-486-5p blocked increases in miR-486-5p and phosphorylated Akt, restored expression of PTEN, and enhanced apoptosis. Coculture of endothelial cells with ECFCs enhanced endothelial miR-486-5p levels. Targeting of PTEN by miR-486-5p was observed in endothelial cells, and PTEN knockdown blocked apoptosis. In mice with ischemic kidney injury, infusion of ECFC exosomes induced potent functional and histologic protection, associated with increased kidney miR-486-5p levels, decreased PTEN, and activation of Akt. Infusion of exosomes from ECFCs transfected with anti-miR-486-5p had no protective effect. Thus, delivery of ECFC exosomes reduces ischemic kidney injury via transfer of miR-486-5p targeting PTEN. Exosomes enriched in miR-486-5p could represent a therapeutic tool in acute kidney injury.

Human endothelial colony-forming cells protect against acute kidney injury: role of exosomes.

The administration of certain progenitor cells is protective in experimental acute kidney injury (AKI), and mechanisms may involve the release of paracrine factors. Endothelial colony-forming cells (ECFCs) are endothelial precursor cells with a high proliferative capacity and pro-angiogenic potential. We examined the effects of human umbilical cord blood-derived ECFCs and their extracellular vesicles in a mouse model of ischemic AKI and in cultured human umbilical vein endothelial cells subjected to hypoxia/reoxygenation. In mice with ischemic AKI, administration of ECFCs (i.v.) at the time of reperfusion significantly attenuated increases in plasma creatinine, tubular necrosis, macrophage infiltration, oxidative stress, and apoptosis, without cell persistence in the kidneys. In cultured human umbilical vein endothelial cells, hypoxia/reoxygenation stimulated apoptosis. This effect was inhibited by incubation with conditioned medium or exosomes (40- to 100-nm diameter) derived from ECFCs, but not by microparticles (100- to 1000-nm diameter) or vesicle-depleted conditioned medium. Administration of exosomes (i.v.) directly to mice with ischemic AKI attenuated renal injury, as assessed by plasma creatinine, tubular necrosis, and apoptosis. Taken together, these studies indicate protective effects of human cord blood-derived ECFCs in experimental AKI and suggest that ECFC-derived exosomes may mediate the protective response via inhibition of endothelial cell apoptosis.