Identifying Premature Ventricular Complexes from Outflow Tracts Based on PVC Configuration: A Machine Learning Approach.

BACKGROUND: Current inferences about the site of origin (SOO) of premature ventricular complexes (PVC) from the surface ECG have not been subjected to newer data analytic techniques that identify signals that are not recognized by visual inspection. AIMS: The objective of this study was to apply data analytics to PVC characteristics. METHODS: PVCs from 12-lead ECGs of a consecutive series of 338 individuals were examined by unsupervised machine learning cluster analysis, and indexes were compared to a composite criterion for SOO. RESULTS: Data analytics found that V1S plus V2S ≤ 9.25 of the PVC had a LVOT origin (sensitivity 95.4%; specificity 97.5%). V1R + V2R + V3R > 15.0 (a RBBB configuration) likely had a LVOT origin. PVCs with V1S plus V2S > 12.75 (LBBB configuration) likely had a RVOT origin. PVC with V1S plus V2S > 14.25 (LBBB configuration) and all inferior leads positive likely had a RVOT origin. CONCLUSION: Newer data analytic techniques provide a non-invasive approach to identifying PVC SOO, which should be useful for the clinician evaluating a 12-lead ECG.

An evaluation of the contribution of routine ultrasound when performed with multiphase CT in renal donor imaging assessment.

OBJECTIVES: We sought to examine the contribution of routine ultrasound when performed with computed tomography in identifying exclusion criteria in potential living kidney donors. METHODS: We performed a 10-year retrospective cohort study including all cases of potential renal donors at our center. For each case, the donor workup ultrasound (US) and multiphase computed tomography (MPCT) original reports and imaging were reviewed by a fellowship-trained abdominal radiologist in consultation with a transplant urologist and placed into one of 3 groups: (1) no significant US contribution, (2) US was useful to characterize an incidental finding (either US exclusive or US aided in CT interpretation) but did not impact donor eligibility, and (3) an US exclusive finding contributed to donor exclusion. RESULTS: A total of 432 potential live renal donors were evaluated (mean age 41, 263 women). In total, 340 (78.7%, group 1) cases had no significant US contribution. In 90 cases (20.8%, group 2), US helped to characterize one or more incidental findings but did not contribute to donor exclusion. In 1 (0.2%, group 3) case, an US exclusive finding (suspected medullary nephrocalcinosis) contributed towards donor exclusion. CONCLUSION: US provided limited contribution to renal donor eligibility decisions when performed routinely with MPCT. CLINICAL RELEVANCE: Routine ultrasound could potentially be omitted in the live renal donor workup, with alternative strategies including a selective approach to incorporating ultrasound and an expanded role of dual-energy CT. KEY POINTS: • Ultrasound is performed routinely with CT for renal donor assessment in some jurisdictions; however, this practice has come into question particularly with advances in dual-energy CT. • Our study found that routine use of ultrasound provided limited contribution, primarily assisting CT in characterization of benign findings with only 1/432 (0.2%) potential donors in a 10-year period excluded based in part on an ultrasound exclusive finding. • The role of ultrasound can be narrowed to a targeted approach for certain at-risk patients, and can be further reduced if dual-energy CT is utilized.

Clinical indicators of slow graft function and outcome after pediatric kidney transplantation.

BACKGROUND: Lesser degrees of perioperative ischemia-reperfusion injury that does not require dialysis may nonetheless influence allograft outcomes, necessitating evaluation of suitable surrogate indicators of perioperative allograft injury. METHODS: This retrospective analysis of pediatric kidney transplants evaluated two indicators representing pace and completeness of recovery, for association with 12-month estimated glomerular filtration rate (eGFR) and first-year rate of eGFR decline: time to creatinine nadir (TTN) and ratio of recipient/donor unadjusted GFR (uGFRR/D ) at 1-month post-transplant. Donor, recipient, and perioperative risk factors were tested further for association with these 2 indicators. RESULTS: 179 patients (190 transplants) aged 13 (IQR 7-17) years and 56% male were included. Twelve-month eGFR was strongly associated with unadjusted GFR at 1 month (uGFR1M , p < .001) and uGFRR/D (p = .003), but not with TTN. None of the indicators was associated with the rate of subsequent eGFR decline after 1-month post-transplant. As a potential surrogate indicator, uGFR1M is effectively modeled by TTN and uGFRR/D (adjusted R2  = 0.57) and is associated with 12-month eGFR (ß = 0.81 ± 0.08; p < .001). Clinical factors associated with uGFRR/D included donor uGFR (p < .001), BSA (p = .026), age (p = .074), and recipient BSA (p < .001). Factors associated with pace of recovery (TTN) included donor uGFR (p = .018), type (p = .019), and recipient BSA (p = .022). CONCLUSIONS: The uGFRR/D ratio, but not TTN, is a useful indicator of perioperative allograft damage that is associated with one-year functional outcome; and uGFR1M is a potential early surrogate outcome. Donor, recipient, and perioperative factors that are associated with slow allograft function are identified.

Cerebrospinal Fluid Pleocytosis Not Attributable to Status Epilepticus in First 24 Hours.

BACKGROUND: Status epilepticus (SE) has traditionally been thought to cause cerebrospinal fluid (CSF) pleocytosis. However, attributing CSF pleocytosis solely to SE without addressing the underlying etiology may lead to poor outcomes. Leukocyte recruitment to CSF has been shown to peak around 24 hours after prolonged seizures in animal studies, suggesting that CSF pleocytosis within the first 24 hours of SE onset may be due to underlying causes. The goal of this study is to assess if SE is associated with CSF pleocytosis, independent of other causes within the first 24 hours of onset. METHODS: We completed a historical cohort study of adult patients with SE admitted to the intensive care unit of Vancouver General Hospital between March 2010 and May 2019. RESULTS: Of the 441 patients admitted with SE during the study period, 107 met our inclusion criteria leading to 111 lumbar punctures (LPs), with 4 patients receiving two LPs. CSF pleocytosis was seen in 12 of 72 patients who underwent an LP within the first 24 hours of SE onset. In all 12 patients, a secondary etiology for the pleocytosis was observed aside from SE. Of the six CSF samples collected after 24 hours of onset that demonstrated pleocytosis, four had no cause for pleocytosis other than SE. CONCLUSIONS: In all 12 patients with CSF pleocytosis in the first 24 hours of onset of SE, an underlying etiology was identified. Therefore, any pleocytosis noticed within the first 24 hours of onset of refractory SE should not be attributed solely to SE.

An improved in vitro model for studying the structural and functional properties of the endothelial glycocalyx in arteries, capillaries and veins.

The endothelial glycocalyx is a dynamic structure integral to blood vessel hemodynamics and capable of tightly regulating a range of biological processes (ie, innate immunity, inflammation, and coagulation) through dynamic changes in its composition of the brush structure. Evaluating the specific roles of the endothelial glycocalyx under a range of pathophysiologic conditions has been a challenge in vitro as it is difficult to generate functional glycocalyces using commonly employed 2D cell culture models. We present a new multi-height microfluidic platform that promotes the growth of functional glycocalyces by eliciting unique shear stress forces over a continuous human umbilical vein endothelial cell monolayer at magnitudes that recapitulate the physical environment in arterial, capillary and venous regions of the vasculature. Following 72 hours of shear stress, unique glycocalyx structures formed within each region that were distinct from that observed in short (3 days) and long-term (21 days) static cell culture. The model demonstrated glycocalyx-specific properties that match the characteristics of the endothelium in arteries, capillaries and veins, with respect to surface protein expression, platelet adhesion, lymphocyte binding and nanoparticle uptake. With artery-to-capillary-to-vein transition on a continuous endothelial monolayer, this in vitro platform is an improved system over static cell culture for more effectively studying the role of the glycocalyx in endothelial biology and disease.