ST elevation after intracoronary administration of Papaverine for fractional flow reserve estimation

INTRODUCTION: Intracoronary (IC) papaverine which is one of the commonly used agents for Fractional Flow Reserve (FFR) estimation has been reported to cause transient ST elevation in some patients. This phenomenon has not been systematically studied. MATERIAL AND METHODS: This is a prospective, observational study. Consecutive patients, who underwent FFR at our institute using IC papaverine from May 2012 to April 2013, were included. FFR was done when clinically indicated. The procedure involved administration of 20 mg papaverine (Paparin)--Troikaa, Ahmedabad) as a fast bolus by intracoronary route followed by a 10 cc contrast flush, following which pressure measurements were made. Continuous ECG recording by Philips Hemodynamic Laboratory was obtained for all patients throughout the procedure. Post procedure, they were observed for any delayed effects and eventual outcome was documented. Fischer's mid-p test was used for statistical analysis. RESULT: Twenty-five patients (18 males, 7 females, mean age 57.9 ± 20 years) underwent FFR using Papaverine. The mean LVEF was (51 ± 15%). Fourteen patients (56%) developed transient ST elevation ≥0.5 mm in one or more leads which resolved spontaneously in all cases without any sequelae. The presence of a significant lesion either in the coronary artery being evaluated or in a remote coronary artery did not predict the ST elevation. 70.5% of diabetics (p = 0.02), 75% of hypertensives (p = 0.008) and 75% of patients with LVH (p = 0.008) had ST elevation. None of the 5 patients without any one of these comorbidities showed ST elevation. CONCLUSION: Transient ST elevation occurs in a significant proportion of cases receiving IC papaverine which is not associated with any adverse clinical outcomes. Micro vascular dysfunction is the most likely mechanism of this phenomenon.