Original Title: Optimal Strategy for Provisional Side Branch Intervention in Coronary Bifurcation Lesions. 3 – Year Outcomes of the SMART – STRATEGY Randomized Trial.
Reference: Song YB et al. J Am Coll Cardiol Intv 2016;9:517-26.
Courtesy of Dr. José A. G. Álvarez.
The present publication is about the three year follow up outcomes of the randomized trial SMART STRATEGY that aimed at comparing side branch intervention aggressive vs. conservative strategies in patients with bifurcation lesions treated with the provisional stenting technique.
The study randomized 258 patients with bifurcation lesions treated with the provisional stenting technique to conservative vs. aggressive strategies, according to whether bifurcations involved the left main or more distal vessels.
In case of left main bifurcations, if after main vessel stenting residual stenosis was 75% in the aggressive group or higher than 50% in the conservative group, the side branch would be dilated with kissing balloon, and after this, side branch stenting if residual stenosis was higher than 30% for the aggressive strategy or 50% for the conservative strategy.
In the case of more distal bifurcations, parameters were >75% residual stenosis (balloon / kissing balloon) and 50% (stent) for the aggressive strategy and < TIMI 3 for the conservative strategy.
Primary end point was the occurrence of Target Vessel Failure (combined final end point of death spontaneous AMI or need for revascularization) within 3 years after procedure. More than 95% of cases received first and second generation stents and intravascular ultrasound.
Main results:
- It was observed that the more conservative strategy had lower incidence of final end point (TVF) (11.7% vs 20.8% p=0.049), a difference observed mainly after the first year; in this group, there was also lower incidence of the hard event, the composite of death and infarction (0.8% vs 6.2%; p=0.036) with similar need of global TLR (8.6% vs 11.5% p=0.43) that tends to be higher in the main vessel than in the side branch.
- Between years one and three, the more conservative strategy resulted also in less need of new main vessel revascularization (and not of the side branch), (0 vs 6.3%; p=0.007).
- The decision to change strategies to a two stent technique was an independent predictor of TVF (HR 5.42, 95% CI 0.03 a 14.5 p<0.001).
- The use of new generation stents was associated independently with a lower incidence of primary end point.
- Finally, the interaction between strategy and result (TVF) is far more evident in bifurcations that do not involve the left main, (in the latter, it is quantitatively lower but not significantly).
Conclusions:
Three year follow up of the study on bifurcations treated with provisional side branch stenting show that a more conservative strategy is associated with better clinical evolution.
Editorial Comment:
The ideal treatment for bifurcation lesions is still far from being established. The provisional stenting technique seems to have advantages when one can achieve a good result using just one stent in the main vessel. However, whether we should intervene the side branch remains unclear. The results of this randomized study show that a conservative strategy in this last point seems to have advantages over a more aggressive strategy, even in situations where the side branch has up to 75% residual stenosis.
Some points deserve further consideration: the generalized use of ultrasound for PCI optimization, the fact that the double stenting technique was exclusively “T stenting” or “T with protrusion” and that patients receiving two new generation stents showed better results than those receiving two first generation stents.
Lastly, evaluating residual lesions only by angiography has high inter observer variability, especially when it comes to ostial lesions, which is shy other methods (FFR?) might offer better information before we decide on therapeutics.
Courtesy of Dr. José A. G. Álvarez. Head of Hemodynamics and Interventional Cardiology at the German and British Hospitals in Buenos Aires, Argentina.