Scrivner O, Fletcher E, Hoffman C, et al. Myoglobinemia, Peripheral Arterial Disease, and Patient Mortality. J Am Coll Surg. 2023, in press.
The ischemia-related damage to skeletal muscle, which is caused by chronic peripheral arterial disease (PAD), produces myoglobin that is released into the circulation. PAD increases the risk for cardiac events and mortality due to cardiovascular disease two- to three-fold in affected patients.
The purpose of this study was to determine whether circulating levels of myoglobin were associated with increased rates of cardiovascular events and mortality in patients with PAD. In addition, effects of myoglobin on endothelial cells and murine aortic contractility were measured.
The authors performed serial measurements of myoglobin concentrations and nitric oxide bioavailability in 40 patients with intermittent claudication and 36 patients with critical limb ischemia; these levels were compared with myoglobin and nitric oxide levels in 33 patients with no evidence of PAD. Rates of mortality and cardiovascular events were recorded over time in both cohorts. Vascular contraction/relaxation and endothelial cell permeability in response to myoglobin were assessed in murine aortas and in-vitro endothelial cells.
The data analysis showed that patients with myoglobin levels >100 ng/ml had significantly higher risk of death compared with patients who had lower levels of myoglobin. Experimental data showed that myoglobin increased endothelial cell permeability and impaired vessel relaxation in murine aortas. The authors concluded that myoglobin is a biomarker for increased mortality risk in patients with PAD, is a potent regulator of arterial health, and may contribute to the vulnerability of PAD patients to cardiac events and death.
Heisser T, Kretschmann J, Hagen B, Niedermaier T, Hoffmeister M, Brenner H. Prevalence of Colorectal Neoplasia 10 or More Years After a Negative Screening Colonoscopy in 120,000 Repeated Screening Colonoscopies. JAMA Intern Med. 2023.
Clinical practice guidelines recommend that screening colonoscopy for detection of colorectal neoplasia be repeated at 10-year intervals after a negative examination. Repeat colonoscopies impose a significant cost and stress on resource capacity. This study assessed the prevalence of advanced colorectal neoplastic lesions at 10 years after a negative screening colonoscopy using data from a national colonoscopy registry.
The study cohort (n = 120,298) consisted of patients 65 years of age or older who had a negative screening colonoscopy 10 years prior to the assessment. The prevalence of advanced neoplasia was 3.6% for women and 5.2% for men; risk for advanced neoplasia increased to 4.9% and 6.6% in both patient groups over time out to 14 years after a negative colonoscopy.
The authors concluded that increasing the recommended screening interval would be safe, especially for women and younger patients.
Major Extremity Trauma Research C, O'Toole RV, Stein DM, et al. Aspirin or Low-Molecular-Weight Heparin for Thromboprophylaxis after a Fracture. N Engl J Med. 2023.
This article reports results of a randomized, non-inferiority trial designed to compare the efficacy and safety of aspirin compared with low-molecular-weight heparin for chemoprophylaxis of venous thromboembolism in patients with fractures. Patients 18 years of age or older (n = 12,211) were randomized to receive aspirin at 81 mg twice daily or low-molecular-weight heparin at 30 mg twice daily.
In- hospital chemoprophylaxis was administered over a median interval of 8.8 days and chemoprophylaxis was prescribed for 21 days after discharge. Mortality (0.78% vs 0.73%) was similar in the two groups. Rates of pulmonary embolism and bleeding complications were also similar. Deep vein thrombosis was diagnosed in 2.51% of patients receiving aspirin and 1.71% of patients receiving low-molecular-weight heparin.
The authors concluded that aspirin was non-inferior to low-molecular-weight heparin and could be recommended despite the slightly increased rate of deep vein thrombosis.
Costa M. Thromboprophylaxis after Extremity Fracture - Time for Aspirin? N Engl J Med. Jan 19 2023;388(3):274-275. doi:10.1056/NEJMe2214045
In the editorial that accompanied the article, Matthew Costa, PhD, noted that practice guidelines should be revised, and that aspirin should be listed as an acceptable form of venous thromboembolism prophylaxis in patients with fractures. Additional studies to determine the effectiveness and safety of aspirin for other surgical conditions were recommended.