Heavily calcified lesions (HCL) continue to present challenges that are not always solved by modern low-profile, non-compliant high-pressure balloons, or bladed balloons. Uncrossable or unexpandable lesions need lesion modification, using ablating devices such as rotational atherectomy. Three cases of HCL treated with drug-eluting stents, using a new intravascular imaging device, Optical Coherence Tomography with 10-fold superior resolution and fewer artifacts compared with conventional intravascular ultrasound, are presented. Insights from using this highly sensitive imaging technique outline the high prevalence of persistent stent strut malapposition in this group, despite the use of high-pressure dilatation or rotational atherectomy.