D1.393 - Safety of Aspirin Oral Provocation in Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

Aspirin is a cornerstone of antiplatelet therapy in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). In patients with an aspirin allergy label, oral provocation allows confirmation of tolerance and administration of the minimal effective antiplatelet dose, avoiding unnecessary aspirin avoidance in a high-risk setting.

We conducted a descriptive retrospective study including 27 patients with ACS undergoing PCI and an aspirin allergy label, in whom aspirin was required at the minimal effective dose of 100 mg, agreed with the Cardiology Department. All patients underwent an oral aspirin provocation protocol administered in four steps of 25 mg. Safety was assessed by recording reactions during provocation and grading severity according to the Ring and Messmer classification. Successful provocation was defined as tolerance to aspirin at the end of the protocol.

Patients’ age ranged from 53 to 93 years, and the majority were women. Regarding index reactions, timing was immediate in most cases when known, while it was unknown in a relevant proportion. When clinical features were available, initial reactions were predominantly cutaneous, mainly urticaria and/or angioedema, with less frequent respiratory symptoms; anaphylaxis had been previously reported in two patients.During the provocation protocol, two patients (7.4%) developed mild late-onset reactions: one presented uvular edema with dysphonia, and one developed angioedema and urticaria. No severe reactions were observed. The agreed target dose was 100 mg in most patients; higher doses were required by cardiology indication in selected cases (200–300 mg). One patient did not tolerate the 300 mg target dose but subsequently tolerated a 100 mg oral provocation, resulting in a final aspirin tolerance rate of 96.3% (26/27). All patients continued aspirin therapy after the procedure.

Aspirin oral provocation using a four-step controlled exposure protocol appears to be safe and feasible in ACS patients undergoing PCI with an aspirin allergy label. Reactions were infrequent, mild, and manageable, allowing administration of the cardiology-agreed minimal effective dose. This controlled exposure approach supports optimal antiplatelet therapy in a high-risk population.