NEW YORK (Reuters Health) – In looking back at patients admitted to a medical ICU in Olmsted County, Minnesota in 2006, clinicians found that those who were on antiplatelet medication before admission were less apt to develop acute lung injury (ALI) than those not on antiplatelet therapy.
“While antiplatelet therapies may prove to be effective prevention and/or early treatment strategies in patients at risk of ALI in the future, the data at this point are hypothesis-generating only and insufficient to change clinical practice,” Dr. Daryl J. Kor, of the division of critical care medicine at the Mayo Clinic in Rochester, Minnesota, noted in an email to Reuters Health.
Platelet activation is a key component of ALI, a potentially fatal condition with few treatment options; therefore, a protective effect of antiplatelet therapy in the setting of ALI has “strong biological plausibility,” the researchers point out in the February issue of Chest.
“As an example, aspirin has been shown to attenuate thromboxane A2 production, which has been associated with ALI in preclinical models,” Dr. Kor said. Antiplatelet therapies may also prevent the formation of platelet-neutrophil aggregates, which are likely important in ALI pathogenesis as well.”
“Antiplatelet therapies may also have a role in the resolution phase of lung injury as they are believed to enhance the production of anti-inflammatory lipid molecules such as 15-Epi-Lipoxin A4 (LXA4). We are currently evaluating some of these potential mechanisms,” Dr. Kor said.
He and colleagues studied the association between prehospitalization antiplatelet therapy and development of ALI and acute respiratory distress syndrome (ARDS) in a population-based cohort of patients at high risk for ALI.
Among a total of 14,479 patients admitted to a medical ICU in Olmsted County during 2006, 161 had at least one major risk factor for ALI but did not meet criteria for ALI at the time of ICU admission and were included in the study. A total of 79 patients (49%) were receiving antiplatelet therapy at ICU admission.
During their ICU stay, 33 patients (21%) developed ALI/ARDS. Patients who were on antiplatelet therapy before admission had a lower incidence of ALI/ARDS (12.7%) compared to those not on antiplatelet therapy before admission (28.0%). The unadjusted odds ratio was 0.37 (P = 0.02).
This association was “robust and remained significant after multivariate adjustment,” the investigators note.
They point out that the benefits of pre-ICU antiplatelet therapy on ALI were apparent despite the fact that the patients receiving antiplatelet therapy were older and had greater severity of illness at the time of ICU admission.
A well-designed clinical trial, Dr. Kor said, is needed to “better define the role of antiplatelet agents in this setting and we will be moving to this next phase of study soon.”
Reference:
Prehospitalization Antiplatelet Therapy Is Associated With a Reduced Incidence of Acute Lung Injury
Chest 2011;139:289-295.
