Hematology
-
Injury is the leading cause of life years lost in the United States, and uncontrolled hemorrhage is the leading cause of potentially preventable death. Traditionally, these patients have been serially resuscitated with large volumes of crystalloid and/or colloids and red blood cells, followed by smaller amounts of plasma and platelets. Transfusion data coming first from the ongoing war in Iraq and Afghanistan and followed by multiple civilian studies have brought into question this tradition-based practice. ⋯ Although there are strongly held opinions and long-standing traditions in their use, there are little quality data within which to logically guide resuscitation therapy. A multicenter prospective observational study is ongoing, and randomized trials are planned. This review will address the issues raised previously and describe recent trauma patient outcome data utilizing predetermined plasma:platelet:red blood cell transfusion ratios, and possibilities for future transfusion products and research.
-
The post-thrombotic syndrome (PTS) is an important chronic complication of deep vein thrombosis (DVT). The present review focuses on risk determinants of PTS after DVT and available means to prevent and treat PTS. More than one-third of patients with DVT will develop PTS, and 5% to 10% of patients develop severe PTS, which can manifest as venous ulcers. ⋯ The cornerstone of managing PTS is compression therapy, primarily using elastic compression stockings. Venoactive medications such as aescin and rutosides may provide short-term relief of PTS symptoms. Further studies to elucidate the pathophysiology of PTS, to identify clinical and biological risk factors, and to test new preventive and therapeutic approaches to PTS are needed.
-
The main reason for the increased risk of thromboembolism in pregnancy is hypercoagulability, which has likely evolved to protect women from the bleeding challenges of miscarriage and childbirth. Women are at a 4- to 5-fold increased risk of thromboembolism during pregnancy and the postpartum period compared with when they are not pregnant. Eighty percent of the thromboembolic events in pregnancy are venous, with an incidence of 0.49 to 1.72 per 1000 pregnancies. ⋯ At the time of delivery, anticoagulation should be manipulated to reduce the risk of bleeding complications while minimizing the risk of thrombosis. There are no large trials of anticoagulants in pregnancy, and recommendations are based on case series, extrapolations from nonpregnant patients and the opinion of experts. Nonetheless, anticoagulants are believed to improve the outcome of pregnancy for women who have, or have had, VTE.
-
Telomeres, repeat sequences at the ends of chromosomes, are protective chromosomal structures highly conserved from primitive organisms to humans. Telomeres inevitably shorten with every cell cycle, and telomere attrition has been hypothesized to be fundamental to normal senescence of cells, tissues, and organisms. Molecular mechanisms have evolved to maintain their length and protective function; telomerase (TERT) is a reverse transcriptase enzyme that uses an RNA molecule (TERC) as the template to elongate the 3' ends of telomeres. ⋯ Additionally, telomere defects associate with predisposition to hematologic malignancy and epithelial tumors. Telomere erosion is abnormally rapid in patients with mutations in telomerase genes but also after hematopoietic stem cell transplant, and telomeres are naturally shorter in older individuals-all conditions associated with higher rates of malignant diseases. In human tissue culture, short telomeres produce end-to-end chromosome fusion, nonreciprocal translocations, and aneuploidy.
-
A 38-year-old morbidly obese male (BMI > 50 kg/m(2)) presents for an elective gastric bypass surgery. He has no personal or family history of venous thromboembolism or hypercoaguability. You are asked by his primary team whether he should receive a retrievable inferior vena cava filter preoperatively for venous thromboembolism prophylaxis.