Abstract Background Rotational atherectomy (RA) has been widely used for severely calcified lesions in performing percutaneous coronary intervention (PCI). The slow flow phenomenon is the most frequently observed complication of RA and leads to prolonged ST-segment elevation. The incidence of the slow flow phenomenon was reported as approximately 5–20%. Several methods have been recommended to treat the slow flow phenomenon; however, the elevation of ST-segment may often persist after disappearance of slow flow phenomenon on angiography. Purpose The aim of the present study was to investigate the clinical factors on the incidence of prolonged ST-segment elevation following ablation of RA. Methods The subject comprised 140 consecutive stable angina patients with severe calcified lesions. All patients had undergone successfully elective PCI using RA and intravascular ultrasound, and had been prescribed strong statins more than 2 week before PCI regardless dyslipidemia. We investigated the occurrence of prolonged ST-segment elevation following ablation of RA with resistance to use of nitroprusside as intra-coronary vasodilators, and the clinical factors including of primary or secondary RA strategy for calcification lesions. Secondary RA strategy was defined as RA performed after pre-dilatation with small balloon (balloon/artery ratio = 0.6). Results Median of age was 71 years (66–80) and 98 cases (70%) were male. Of 140 target lesions, 82 (59%) were LAD (RCA; 24%, LCX; 16%, and LMT; 1%, respectively). The rates of hemodialysis and diabetes mellitus were 31% and 61%. The incidence of prolonged ST-segment elevation with resistance to use of nitroprusside as intra-coronary vasodilators was 8 cases (6%). Major complications of RA including coronary perforation, coronary rupture, burr entrapment and cardiogenic shock requiring the mechanical support were none. Univariate logistic regression analysis showed that age [Odds ratio (OR); 1.07, 95% confidence interval (CI) 0.99–1.17, p=0.103], hemodialysis (OR; 0.71, 95% CI: 0.10–3.25, p=0.688), diabetes mellitus (OR; 1.08, 95% CI: 0.25–5.46, p=0.915), use of β-blocker (OR; 0.70, 95% CI: 0.14–2.96, p=0.633), left ventricular ejection fraction (OR; 0.99, 95% CI: 0.94–1.05, p=0.781), lesion length ≥20mm (OR; 1.04, 95% CI: 0.23–7.33, p=0.962), and burr size (OR; 2.42, 95% CI: 0.53–16.95, p=0.289) were not associated with the incidence of prolonged ST-segment elevation. Multivariate logistic regression analysis for the incidence of prolonged ST-segment elevation revealed that secondary RA strategy and levels of low-density lipoprotein cholesterol (LDL-C) were independent factors of the incidence of prolonged ST-segment elevation following ablation of RA (OR; 0.05, 95% CI: 0.01–0.39, p=0.017 and LDL-C: OR 0.91, 95% CI 0.83–0.96, p=0.010, respectively). Conclusion Secondary RA strategy may be useful to reduce the occurrence of prolonged ST-segment elevation following ablation of RA. Funding Acknowledgement Type of funding sources: None.