The outcomes of patients with very small coronary artery disease treated with thin strut cobalt chromium bare metal stents: an observational study

BACKGROUND: Percutaneous coronary interventions (PCI) in coronary artery disease (CAD) with very small vessel diameters remains controversial and challenging. These lesions are usually more diffuse, calcified and tortuous. The usage of thin strut bare metal stents (BMS) with excellent crossing profiles in a very small caliber coronary lesions has increased the likelihood of procedural success. OBJECTIVES: This observational study assessed the 9-month clinical outcomes in an ‘all-comers’ population with very small caliber CAD after implantation of thin strut cobalt chromium BMS. METHODS: Thin strut cobalt chromium BMS implantation in a priori pre-defined subgroups was investigated in a non-randomized, international, multi-center ‘all-comers’ observational study. Primary end-point was the 9-month clinically driven target lesion revascularization (TLR) rate. Secondary end-points included the 9-month major adverse cardiac event (MACE) and procedural success rates. Data collection was done using an established electronic data acquisition form with built-in plausibility checks. RESULTS: A total of 783 patients with a mean age of 70.4 ± 12.8 years were enrolled, 205 (26.2 %) of them had vessel diameters of 2.5 mm and smaller which was defined as CAD with very small reference vessel calibers. Older age and diabetics were associated with higher incidences of very small caliber vessels. The mean reference vessel diameter in the very small vessel group was 2.05 ± 0.27 mm and mean diameter for vessels >2.5 mm was 3.41 ± 0.55 mm. Pre-dilatation was performed more often in the very small vessel patients (52.2 vs. 42.2 %; p value 0.007). There was no difference in the overall technical success rates in very small vessel disease group (97.9 vs. 97.7 %). The 9-month TLR rate was 6.3 % for the very small vessels and 3.7 % for vessels >2.5 mm (p = 0.129). The 9-month and in-hospital MACE rates in the very small vessel group and patient with vessel diameters >2.5 mm were not significantly different (13.1 vs. 9.2 %; p = 0.1265 and 5.2 vs. 3.7 %; p = 0.349) respectively. CONCLUSION: This study has demonstrated that the use of thin strut cobalt chromium BMS in very small vessel CAD was reasonably safe and efficacious in the context of ‘real-world’ practice.