ARLINGTON, VA. — The approach to treating bifurcated lesions—using one stent or two—should depend on the size of the side branch, recommended Dr. Samin K. Sharma at a meeting sponsored by the Cardiovascular Research Institute at Washington Hospital Center.
About 15% of coronary interventions involve some type of bifurcation. These lesions are often complex and are associated with greater lumen loss and longer stents, said Dr. Sharma, director of the cardiac catheterization laboratory at Mount Sinai Medical Center in New York.
He offered a treatment algorithm for bifurcations, based on side branch size:
▸ Large. If the side branch is greater than 2.5 mm, “we all believe that we should use two stents,” said Dr. Sharma. He noted that there are no data from randomized trials showing that this approach is better in terms of restenosis.
▸ Medium. With side branches of 2.25–2.5 mm diameter, stent the main vessel but avoid putting a stent in the side branch.
Opening the side branch is important. “Leave the wire in the side branch. We learned in bifurcation lesions that if we leave the wire in the side branch, it's better,” in terms of decreased compromise and loss of lumen. The branch can be stented if there is restenosis at some point.
▸ Small. If the side branch is smaller than 2.25 mm, stent only the main branch and leave the wire in the side branch.
A number of stent techniques have been developed to deal with the special challenges of bifurcated lesions, Dr. Sharma said. The conventional technique for bifurcations—developed during the bare-metal stent era—is to stent the main vessel, with plaque modification of the side branch and provisional stenting of the side branch as necessary. “Even with a drug-eluting stent [this technique] seems to be the optimal treatment in the majority of bifurcation lesions,” said Dr. Sharma. If the result in the side branch is suboptimal, a stent will be required. However, if there is a dissection in the side branch prior to stenting the main vessel, then the side branch should be stented first, followed by the main vessel.
The crush technique involves advancing a stent into the side branch (without expansion) and advancing another stent into the main vessel (without expansion), fully covering the bifurcation. The side branch stent is retracted into the main vessel, then expanded. The main vessel stent is then expanded. The side branch stent is crushed against the main branch stent.
“The data have shown that you need to do a follow-up kissing balloon dilation. If you don't, there is a high incidence in the event rate, in terms of restenosis and the major adverse cardiac events,” said Dr. Sharma, who is also codirector of the Cardiovascular Institute at Mount Sinai Medical Center.
The kissing balloon dilation is more important for the side branch than for the main vessel. The thrombosis rate with the crush technique is about 2%–3%.
The simultaneous kissing stent technique involves advancing a stent to the side branch, followed by one to the main vessel. The two stents are then simultaneously pulled back to the bifurcation and then into the proximal part of the main vessel, configuring a Y (with the stem of the Y in the main vessel, completely covering the proximal end of the lesion, one arm in the distal main vessel, and one arm in the side branch). “This is very suitable for the distal left main bifurcation but also for left anterior descending coronary artery diagonals,” said Dr. Sharma. He recommends initial inflation of about 8–10 atmospheres (atm), then deflation, then expansion up to 18–20 atm and deflation. This should be followed up with simultaneous balloon inflation at 8–10 atm. The researchers compared the simultaneous kissing stent and the conventional technique; target lesion revascularization was 18% for the conventional technique and 5% for the kissing stent technique. There was no late thrombosis (Am. J. Cardiol. 2004;94:913–7).
Emily Brannan, Illustration
Here, the kissing technique is used to place stents at a bifurcated lesion of the left main, left anterior descending, and left circumflex coronary arteries. Courtesy Dr. Samin K. Sharma