Faculty Bibliography

BACKGROUND:The association between coronavirus disease 2019 (COVID-19) and hypercoagulability has been extensively described, and pulmonary embolism is a recognized complication of COVID-19. Currently, the need for computed tomography pulmonary angiogram (CTPA) relies on the Wells score and serum D-dimer levels. However, because COVID-19 patients have a different thrombotic and inflammatory milieu, the usefulness of the Wells score deserves further exploration for this patient population. We aimed to explore the ability of the Wells score to predict pulmonary embolism in patients with COVID-19. METHODS:In this retrospective study, patients found to have a CTPA and a COVID-19 diagnosis during the same admission were selected for analysis. Age and sex, CTPA results, and associated D-dimer levels were entered in a database. The Wells score sensitivity and specificity were calculated at different values, and the area under the curve of the receiver operating characteristic curve measured. RESULTS:Of 459 patients with COVID-19, 64 had a CTPA and 12 (19%) had evidence of pulmonary embolism. Previous or current evidence of deep vein thrombosis, a Wells score above 4 points, and serum D-dimer levels 5 times above age-adjusted upper normal values were associated with pulmonary embolism. However, only 33% of patients with pulmonary embolism had a Wells score of 4 points or higher. The area under the curve of the receiver operating characteristic showed non-discriminating values (0.54) CONCLUSIONS: Although a Wells score of 4 or more points predicted pulmonary embolism in our cohort, the outcome can be present even with lower scores.

Dual anti-platelet therapy denotes a regimen of aspirin plus a P2Y₁₂ receptor inhibitor, clopidogrel, prasugrel, or ticagrelor. Such therapy is a cornerstone of medical management following acute coronary syndromes and is imperative following percutaneous coronary interventions. While there is uncertainty about the optimal duration of dual antiplatelet therapy following percutaneous coronary intervention, the new 2016 American College of Cardiology/American Heart Association Guidelines suggest that for patients with stable ischemic heart disease at least six months of such therapy following a drug eluting stent and one month following a bare metal stent should be implemented. In patients with acute coronary syndrome including non-ST elevation and ST elevation myocardial infarction it is recommended to extend dual antiplatelet therapy treatment to one year in both drug eluting stent and bare metal stent groups. There may be latitude for earlier discontinuation in appropriately selected patients; extended dual antiplatelet therapy beyond one year may be beneficial in others. Herein, we describe current guidelines and evidence supporting if and when dual antiplatelet therapy should be interrupted for surgery for patients who have undergone percutaneous coronary intervention.

Gene conversion, the non-reciprocal exchange of genetic information, is one of the potential products of meiotic recombination. It can shape genome structure by acting on repetitive DNA elements, influence allele frequencies at the population level, and is known to be implicated in human disease. But gene conversion is hard to detect directly except in organisms, like fungi, that group their gametes following meiosis. We have developed a novel visual assay that enables us to detect gene conversion events directly in the gametes of the flowering plant Arabidopsis thaliana. Using this assay we measured gene conversion events across the genome of more than one million meioses and determined that the genome-wide average frequency is 3.5×10(-4) conversions per locus per meiosis. We also detected significant locus-to-locus variation in conversion frequency but no intra-locus variation. Significantly, we found one locus on the short arm of chromosome 4 that experienced 3-fold to 6-fold more gene conversions than the other loci tested. Finally, we demonstrated that we could modulate conversion frequency by varying experimental conditions.