Does initial use of large versus small burr size in left main stem bifurcation impact clinical and procedural outcomes?
Authors: Alatta A , Ibrahem A , Bawamia B , Gungoren F , Farag M , Egred M 
Published: October 2024

Abstract

Background
Coronary calcifications, detected in up to 25% of treated coronary lesions nowadays, has a well-known association with complications during PCI, particularly for left main stem (LMS) interventions. Current guidelines recommend coronary artery bypass grafting for patients with LMS disease, particularly with high SYNTAX score ≥ 33. However, in those with increased surgical risk, PCI can be used particularly with use of rota-ablation (RA). RA is a well-established treatment for heavily calcified disease particularly in non LMS sites. However, data on the safety and efficacy of use of RA in LMS bifurcation management is limited. Current guidelines recommend using a small burr size at the start, with upsizing burrs if required. Whether upfront use of large burr size ≥ 1.75 versus smaller burr size in this context in is safe or effective is unknown.

Methods
This was a retrospective, single centre, study. Included patients undergoing RA to LMS bifurcation disease. Standard procedures for RA were applied to each case, following current national and international intraprocedural standards. The main study outcomes were overall mortality at 1 year, and a comparison of mortality at 1 and 4 years between groups and repeat target lesion revascularization at 4 years.

Results
To our knowledge, this is the largest series of LMS rota-ablation cases, with the longest available follow up. Between June 2009 and October 2021, we included 243 patients with a mean age of 74.7±9 years. Males formed 80% of the cases. 51.4% of patients were treated with a large bur size ≥ 1.75mm, with more males being treated with large burr size. Most treated lesions were true bifurcations (85.6%). Treated lesions were complex (Syntax score = 35.3 ± 10.6). Radial access was used in almost two thirds of patients, with size 7F sheath being the most used.
Intravascular ultrasound was more commonly used with large burr size (p = 0.017). Upfront 2-stent techniques, predominantly culotte, was employed more often with large burr size. Provisional technique was used more often in the small burr size group. The burr size to vessel size was 0.4 in small burr group versus 0.48 in large burr size using stent size as a surrogate for vessel size. Post dilatation balloons were larger as well as stent size in the large burr group. The overall 1-year mortality for the group was 12.7% similar to international literature. Importantly, procedural complications were not different between groups, and similarly mortality at 1 and 4 years, p = 0.082 and p = 0.384 respectively. There was no difference between groups in terms of repeat vessel revascularization at 4 years p=0.487.

Conclusions
Upfront use of large burr size ≥ 1.75 is feasible and safe to treat LMS bifurcation disease with no increase in procedural complications or mortality and target lesion revascularization on long term follow up. It is notable that in-hospital mortality for this cohort was low at 1.6% in comparison to previous studies.1 and 4 year mortality KM curves