Late lumen enlargement after drug-coated balloon therapy: turning foes into friends

Assessing temporal changes in the coronary lumen provides the basis to elucidate the relative efficacy of different percutaneous coronary interventions (PCI). In this regard, angiographic late lumen loss (LLL; minimal lumen diameter [MLD] after intervention minus MLD at follow-up), as measured by quantitative coronary angiography (QCA), has been classically enthroned as the gold standard for efficacy. However, LLL depends on the acute gain (“the more you gain, the more you lose”) due to the exaggerated tissue reaction elicited by the vessel wall injury that, although attenuated, persists despite the incorporation of antiproliferative drugs. Accordingly, LLL is far from ideal for comparing the efficacy of devices with different acute gain. This typically affects comparisons of drug-eluting stents (DES) versus drug-coated balloons (DCB), where other surrogate angiographic parameters, such as MLD and % diameter stenosis at follow-up, provide more meaningful information1. In addition, from the early studies, it was also recognised that LLL frequency distribution curves showed a unique pattern with the appearance of “negative” LLL, or late lumen enlargement (LLE), in a subset of patients. This phenomenon is of particular...