Iodine Allergy and Percutaneous Coronary Intervention Consequences among Chest Pain Patients hospitalized in Internal Medicine Wards

Background: Exposure to contrast material during Percutaneous coronary intervention (PCI) in a patient with known Iodine allergy may be catastrophic. In recent years the use of pre-medication and low-osmolality contrast media have been introduced. However, whether these protocols have led to decrease in the occurrence of reactions is not clear.
Objective: To assess whether prior iodine allergy and further premedication alter the clinical outcome of patients with chest pain undergoing PCI.
Methods: We conducted a retrospective analysis of 13,652 patients who were hospitalized during 2010-2016 in the internal medicine wards of Meir Medical Center with chest pain. Patients were searched for prior diagnosis of Iodine allergy. Medical charts were then analyzed. Primary outcomes were: 1) physician awareness of iodine allergy prior to PCI 2) pre-medication according to the protocol 3) allergic reaction to the contrast material.
Results: A total of 279 (2%) patients (mean age: 65.5±10 years, 42% male) had prior diagnosis of Iodine allergy. Thirty five (12%) of these patients underwent PCI during the index hospitalization. The allergy was recognized by the physicians in only 11 (33%) cases and a specific pre-medication protocol was initiated in 10 (91%) of them. Only 5 patients developed an allergic reaction: 2 patients demonstrated hypotension and one patient was documented with skin rash. 2 had prior Iodine allergy diagnosis who was un-noticed and therefor did not receive prior steroid treatment. No death events were documented in the following 30-day among all patients with known iodine allergy who underwent PCI.
Conclusion: Only minority of patients with Iodine allergy underwent PCI were noticed prior to the procedure and underwent pre-medication. Insignificant allergic reaction was documented in only 12% of patients undergoing PCI. It seems that the medical significance of Iodine allergy is minor.