Drug-coated balloons (DCBs) are increasingly utilised in the management of de novo coronary lesions, offering a stent-free alternative with potential advantages in ST-elevation myocardial infarction (STEMI), where microvascular integrity is often compromised. Therefore, there is a potential risk of particulate embolisation from DCB (Sirolimus or Paclitaxel) coatings, which may influence the reperfusion outcomes. Paclitaxel-coated balloons (PCBs) typically employ macro-particulate drug coatings visible to the naked eye, whereas sirolimus-coated balloons (SCBs) utilise nanoparticle formulations. The impact of these differing particle sizes on microcirculatory perfusion and angiographic outcomes in STEMI remains unexplored. This study evaluates post-procedural TIMI flow in patients undergoing DCB-only angioplasty with either PCB or SCB.

This is a single-centre, retrospective observational study conducted at Heartlands Hospital, UK. 212 STEMI cases treated with a DCB-only approach, between 2018 and 2022, were analysed. Patients received either PCB (n= 50) or SCB (n= 162). Study endpoints were comparison of the post-DCB TIMI flow (0-3), DCB diameter and length, and frequency of bailout stenting (due to recoil > 30% or flow-limiting dissection) for both DCB devices. A chi-square test was applied to assess statistical differences in TIMI 3 flow rates between the two devices.

Final TIMI 3 flow was achieved in 74% of PCB and 88.9% of SCB cases (p < 0.01). Bailout stenting was infrequent (10% vs 8% respectively). Mean DCB diameter and length were comparable between the two cohorts (Diameter: 2.745 mm vs 2.801 mm; Length: 28 mm vs 27.5 mm, respectively). No significant differences were observed in lesion preparation techniques, including the use of non-compliant/semi-compliant balloons, cutting balloons, or intravascular imaging (IVUS/OCT).

This study suggests that drug-coating particle size may influence microvascular reperfusion in STEMI patients undergoing DCB-only angioplasty. The lower TIMI 3 flow observed in the PCB group may reflect macro-particulate embolisation and impaired microcirculatory recovery, whereas nanoparticle-based SCBs appear to preserve the perfusion more effectively. These findings support further investigation into the role of drug formulation in DCB performance and underscore the need for prospective, device-specific trials to optimise DCB use in primary PCI.