Iatrogenic coronary artery dissections - direct visualization and mechanistic insights from the Visible Heart Laboratories

Background: Percutaneous coronary intervention (PCI) frequently causes limited coronary artery dissections, but angiography is imprecise in assessing the presence or hazard of induced dissections. Bloodless angioscopy during instructional PCI, which is possible in the Visible Heart Laboratories (VHL), can provide valuable insights into dissection morphology and creation. Aims: We aimed to investigate periprocedural coronary artery dissections in porcine hearts during educational bifurcation stenting sessions in the VHL. Methods: Between July 2019 and October 2023, expert operators performed bifurcation PCI on the Visible Heart® apparatus (bloodless beating heart system). Interventional strategies were at the operator's discretion, though intentional stent oversizing is necessary to prevent stent migration, which predisposes to dissections. Angioscopy and Optical coherence tomography (OCT) footage was reviewed for dissections, which were categorized by morphology, creation mechanism and progression in extent. Results: Of 119 bifurcation PCIs, 53 showed coronary artery dissections. Two main dissection morphologies emerged: Longitudinal (in line with vessel, n=14) and transverse dissections (n=34). Transverse tears, caused by deep angioscope/guide catheter intubation (n=29), attempts to cross balloons against resistance (n=3), but also by kissing balloon inflations (n=1) and geographical miss (n=1) of post-dilatation, progressed in 80.2% of cases (118.8±79.4° to 195.1±116.7° lateral extension, p<0.001). Longitudinal coronary artery dissections predominantly resulted from first kissing balloon inflation during double kissing (DK) crush technique and did not progress relevantly (2.9mm [2.4 - 4.2] to 3.1mm[2.7 - 4.7], p=0.68). Conclusions: This is the first report demonstrating angioscopic images of coronary artery dissections. Two different dissection morphologies emerged: Transverse dissections that can quickly progress to become flow-obstructing flaps, and longitudinal dissections that appear more stable.