Purpose To determine the clinical efficacy of emergency pretreatment regimens for contrast allergy in STEMI patients undergoing PPCI.
Methods We retrospectively identified all individuals with a history of contrast allergy who presented with STEMI, were pretreated for contrast allergy, and underwent PPCI at our medical center between January 2005 to May 2018. Emergency pretreatment regimen included a combination of intravenous (IV) steroid, IV famotidine and IV diphenhydramine administered immediately before PCI. Laboratory records, inpatient notes, and discharge summaries were reviewed to confirm the severity of the original contrast allergy and identify any allergic breakthrough reaction after pretreatment with an emergency regimen. Reactions were characterized as mild, moderate, severe, or of unknown severity.
Results During the study period 15,712 individuals underwent PCI, of which 176 patients presented with STEMI, had confirmed contrast allergy, and were pretreated before undergoing PCI. No patient with a history of contrast allergy underwent PPCI without pre-treatment. Mean age was 64 years, with 52% males, and all individuals were white. The majority had hypertension (77%), 67% had dyslipidemia, 29% had diabetes mellitus, and 20% patients had a prior history of MI. Intravenous steroids used in the emergency regimen included methylprednisone (n = 100), hydrocortisone (n=70), and dexamethasone (n = 6). The original allergic response to ICM was mild in 59% patients, moderate in 15%, severe in 20% and of unknown severity in 13% patients. Of the 176 patients only 10 (5.6%) developed a breakthrough reaction. Most of which were mild; none was fatal. Median length of hospital stays was three days and nine patients (10.8%) passed away within 30 days of hospital admission.
Conclusions Patients with prior contrast allergy presenting with STEMI can safely undergo PPCI after emergency pretreatment. Breakthrough reactions are infrequent and mild.