Effect of aspirin on acute changes in peripheral arterial stiffness and endothelial function following exertional heat stress in firefighters: The factorial group results of the Enhanced Firefighter Rehab Trial

Abstract

Peripheral arterial stiffness and endothelial function, which are independent predictors of cardiac events, are abnormal in firefighters. We examined the effects of aspirin on peripheral arterial stiffness and endothelial function in firefighters. Fifty-two firefighters were randomized to receive daily 81 mg aspirin or placebo for 14 days before treadmill exercise in thermal protection clothing, and a single dose of 325 mg aspirin or placebo immediately following exertion. Peripheral arterial augmentation index adjusted for a heart rate of 75 (AI75) and reactive hyperemia index (RHI) were determined immediately before, and 30, 60, and 90 minutes after exertion. Low-dose aspirin was associated with lower AI75 (-15.25±9.25 vs −8.08±10.70, p=0.014) but not RHI. On repeated measures analysis, treatment with low-dose aspirin before, but not single-dose aspirin after exertion, was associated with lower AI75 following exertional heat stress (p=0.018). Low-dose aspirin improved peripheral arterial stiffness and wave reflection but not endothelial function in firefighters.

Overexertion and heat stress in the fire service: a new conceptual framework

“…11,12 Additionally, prolonged firefighting has a negative effect on vascular function, contributing to increased arterial stiffness and wave reflection. 13,14 Exposure to extreme heat and physical exertion during firefighter simulation also has been shown to increase thrombogenicity, decrease vascular function, and cause myocardial injury in healthy firefighters. 15 These results indicate the pathways between firefighter work and cardiovascular mortality, including that arising from acute myocardial infarction.…”

Efecto de ácido acetilsalicílico sobre la rigidez arterial en el embarazo en una población colombiana: estudio de cohorte prospectivo

“…Se ha encontrado que la administración de aspirina tiene un efecto favorable en la rigidez aórtica en pacientes hipertensos y en otros individuos (25). El impacto de dosis bajas de aspirina en los índices de rigidez arterial, específicamente en las embarazadas, no es claro; estudios que han evaluado la rigidez arterial han excluido a aquellas que están usando ASA (25)(26)(27)(28) o no informan el uso (8), se considera que existe un vacío del conocimiento en este asunto, y su estudio pudiera ampliar la información acerca de los mecanismos por los cuales el uso de ASA tiene beneficios en la prevención de preeclampsia.…”

Firefighting: Can our arteries take the heat?

“…These open questions are the subject of two articles published in the current issue of Vascular Medicine. 11,12 Lefferts and colleagues explore the impact of moderate exercise induced heat stress (EIHS) compared to normothermic exercise on aortic stiffness, pressure from wave reflections and non-invasive estimates of myocardial work and coronary perfusion. 11 Twelve young, healthy, and physically active men were randomized in a crossover design to two distinct alternative exercise/rest protocols: no heat stress (NHS) and heat stress (HS).…”

“…In light of previously reported associations of heat stress with both inflammation and platelet activation, Olafiranye and colleagues report a study designed to test the hypothesis that anti-platelet therapy with aspirin (ASA) could prevent and/or reverse the adverse effects of heat stress in a simulated firefighting environment. 12 In the setting of a 2 x 2 factorial design study, 52 primarily male firefighters were randomized to either two weeks of low-dose (81 mg) aspirin prior to exposure to heat stress or placebo control and to either a single dose of 325 mg aspirin immediately post heat stress exposure or placebo control. Compared to the study by Lefferts and colleagues, subjects enrolled were older, with higher blood pressure (still within normal range) and body mass index.…”

“…Both studies reported in this issue suggest that heat stress has unique adverse effects on the microvasculature of firefighters independent of the other potential stressors that occur during firefighting. 11,12 The favorable effects of aspirin reported by Olafiranye and colleagues suggest the potential for pharmacotherapy to mitigate the adverse effects of heat stress and could favorably impact CV risk in firefighters. Future studies designed to determine optimal timing and dosing of aspirin as well as its overall efficacy are still needed prior to making a definitive recommendation for aspirin therapy as a preventive medication for all firefighters.…”