Background:
The most frequent complex interventions one encounters in the cath lab are bifurcations. Treatment of those lesions developed over recent years and different techniques were added to the armamentarium. There is still debate about optimal treatment. Provisional stenting is a safe and simple technique and recommended by the EBC in most cases. Treating the SB with drug eluting balloon (DEB) may add benefit to this strategy. Aim of this study is to prove that treating the side branch with drug eluting balloon is safe and feasible in bifurcation lesions and to evaluate if there is a benefit in this strategy.

Methods:
In this prospective multi-center registry we included 98 consecutive patients, >18years of age, regardless of gender, with denovo coronary bifurcation lesion. Indication for coronary angiography could be CCS or ACS (NSTE-ACS or instable angina). Patients with STEMI, stenosis of the unprotected LMS, cardiogenic shock, angiographic visible thrombus within the target lesion, restenosis of a previous treated lesion, CTO, suspected life expectancy <1 year or suspected intolerance to paclitaxel, aspirin, clopidogrel, ticagrelor or prasugrel were excluded.  For this subgroup analysis we further selected 88 patients with relevant SB stenosis and divided them in 2 groups, one treated with SB DEB (SB DEB group, n=71) and one without (SB non DEB group, n=17). Angiographic images were evaluated by a core lab. Follow-up was 9 months.

Results:
Baseline characteristics did not differ. About 45% of patients had three vessel disease. DEB was more often used in LAD/Diagonal bifurcations (p<0,001), RCX/OM bifurcation was more often treated without DEB (p=0,001). Final kissing balloon inflation was performed significantly more often in the SB DEB group (74,7% vs. 47,1%; p=0,02). Post dilatation lumen gain did not differ. Prasugrel was mainly used in the SB non DEB group where Clopidogrel was most used in the SB DEB group (p<0,001). Target lesion revascularization as primary endpoint was observed in 3 cases of the SB DEB group and no case in the SB non DEB group. MACE rate during the whole follow-up remains low with none in the  non DEB group and 9 MACE in 7 patients in the DEB group.

Conclusion:
Distribution of the lesion location showed a significant accumulation of LAD/Diagonal lesions in the SB DEB group whereas RCX/OM lesion were the dominant location in the SB non DEB group. Possible due to the more bulky profile of DEB that may complicate balloon placement especially in smaller or steeper angulated side branches. The post dilatation lumen gain in the SB was comparable in both groups. So, the DEB is non-inferior in this context. What has to be discussed is the postinterventional treatment with dual antiplatelet therapy. Aspirin was the usual treatment for patients without the need for OAC. What significantly differs is the used P2Y12-inhibitor. In the DEB group the most used drug was clopidogrel whereas in the non DEB group prasugrel was more frequent used. We know from the TRITON-TIMI 38 study that in acute coronary syndromes prasugrel is associated with significantly reduced ischemic events including stent thrombosis. This could have a relevant effect on the results of the major adverse cardiac events in the DEB group.
So in conclusion provisional stenting of the main branch and treatment of the SB with DEB is a safe and feasible way to handle bifurcation lesions. If this strategy is beneficial, further studies are necessary.