Five-year angiographic and clinical follow-up of patients with drug-eluting stent implantation for symptomatic myocardial bridging in absence of coronary atherosclerotic disease.

OBJECTIVES The objective of this study was to determine the long-term efficacy and dynamics of systolic and diastolic luminal changes within the bridged segments of coronary arteries after intracoronary stenting with drug-eluting stent (DES) in patients (pts) with symptomatic myocardial bridging (SMB) in the absence of coronary atherosclerosis. BACKGROUND Although myocardial bridging (MB) represents a benign disease in the majority of pts, in its severest forms it is clinically manifested as typical or atypical angina, myocardial ischemia, myocardial infarction, left ventricular dysfunction, atrioventricular conduction disturbance, exercise-induced ventricular tachycardia, or sudden death. The only existing prospective study of 11 pts with SMB treated with bare-metal stent (BMS) reported a 36% in-stent restenosis (ISR) rate at 7 weeks repeated quantitative coronary angiography (QCA). METHODS The study consisted of 15 consecutive patients (13 men and 2 women) with SMB of the mid-portion of the left anterior descending (LAD) coronary artery (and in 1 patient, concomitant MB of the left circumflex [LCX] coronary artery) and luminal diameter systolic narrowing of the tunneled segment of ≥50%, underwent percutaneous coronary intervention with DES. Clinical and non-invasive assessments of myocardial ischemia were determined every 6 months over 5 years and QCA was performed 12 and 24 months post procedure if not urged differently by deterioration of clinical symptoms and/or presence of positive ischemia tests. The minimal systolic and diastolic luminal diameters of the bridged/stented segments were measured before, immediately after, and 12 and 24 months post procedure by two independent observers blinded to each other's readings, using QCA commercial software. The endpoints of the study were ISR, target lesion revascularization (TLR) rate, in-stent diameter late luminal loss (LLL), and permanent disappearance or significant improvement of clinical symptoms. RESULTS After 12 months, ISR and TLR in 16 treated vessels was 18.7%, LLL was 0.2 ± 0.6 mm and permanent disappearance or significant improvement of symptoms was achieved in all 15 pts. In 3 pts, clinically-driven repeat revascularization was necessary within the first 6 months. In 1 patient, coronary perforation complicated stent deployment and was immediately resolved by stent-graft implantation, followed by completely uneventful recovery. CONCLUSIONS DES implantation in pts with SMB resistant to medical treatment results in prompt and long-term increase of systolic and diastolic luminal diameters, and long-lasting relief of clinical symptoms. Compared to BMS, stenting of SMB with DES resulted in significantly lower ISR and TLR rate.