No-reflow complicating chronic total occlusion coronary revascularization

Objectives. To assess the incidence of no-reflow in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI), analyze possible causes and differential diagnoses, and identify useful management approaches. Methods. In this multicenter observational study, all CTO-PCIs performed between January 2018 and April 2019 were reviewed to collect no-reflow complications, defined as Thrombolysis in Myocardial Infarction (TIMI) flow ≤1 in a patent epicardial artery. Patient clinical, anatomical, and procedural characteristics were analyzed. Results. Out of 461 PCIs, two (0.43%) were complicated by no-reflow. In 1 case, PCI was performed on a long segment of the right coronary artery, after use of a dissection-re-entry technique by knuckle wiring. In the second patient, no-reflow developed after proximal left anterior descending coronary artery stenting, with a short subintimal tracking. Intravascular ultrasound was used to exclude complications in the epicardial vessel in both cases. Distal embolization seems the most plausible cause, and intracoronary adenosine effectively improved flow. Both patients had a type 4a myocardial infarction, asymptomatic in the first case, and associated with chest pain, electrocardiographic changes, and new regional wall-motion abnormality at echocardiography in the second case. Conclusions. No-reflow in CTO recanalization is rare, but associated with a high risk of periprocedural myocardial infarction, with incomplete protection from ischemia offered by the pre-existing collateral network.