Shelley Wood

October 23, 2008

October 23, 2008 (Washington, DC) — Provisional T-stenting using the Taxus stent, instead of the crush or culotte techniques, is associated with a lower rate of death, MI, and target-vessel failure (TVF) at one year, results from the British Bifurcation Coronary Study: Old, New, and Evolving Strategies (BBC ONE) show. The findings, driven largely by increased procedural MI in patients treated with a more complex crush or culotte technique, are in line with a growing body of evidence supporting the idea that when it comes to stenting branch lesions, less is more.

The challenge now, says Dr David Hildick-Smith (Sussex Cardiac Centre, Brighton, UK), who presented the study here at the TCT 2008 meeting, is to determine which lesions truly will require a two-stent strategy.

"I think it's fair to say that the concept of the routine use of a more complex strategy in bifurcation lesions is pretty much buried," Hildick-Smith told heartwire . "And what we need to work out is, if provisional T-stenting is the gold standard in the majority of bifurcation lesions--and all the people who do bifurcations at a high volume believe that there are lesions where a single-stent strategy will not do the job--how we design a study that actually demonstrates that there is a role for a two-stent strategy."

BBC ONE enrolled 500, mostly stable CAD patients with bifurcation lesions, randomized to either a simple or complex treatment strategy. The "simple" technique entailed stenting the main vessel, then only stenting the side branch (using a T-stent technique) if TIMI flow was less than 3, ostial pinching of the side branch was >70%, or there was threatened side-vessel closure or dissection. In the "complex" arm of the study, either the culotte or crush two-stent techniques could be used, at operator discretion. Kissing-balloon inflation was mandatory for all three techniques.

The primary end point for BBC ONE was death, target-vessel failure (revascularization or inadequate TIMI flow), or MI at nine months. As expected, procedural differences were marked between the two groups, with patients in the "complex" group having significantly greater stent length, longer procedural times, and more radiation exposure, contrast, guidewires, balloons, and stents used. In the provisional T-stenting group, only seven patients ultimately required two stents, while in the complex group, four patients crossed over to a "simple" approach, by operator's decision. In both arms, the rate of "true bifurcation," meaning significant disease in both the main and branch artery, was 80%.

Numerically, rates of death, MI, and TVF were higher in the complex group, leading to a statistically significant difference in the primary composite end point. Further analyses indicated that periprocedural and in-hospital MI were largely responsible for the differences between the two groups.

BBC ONE End Points: Nine Months

End point Complex (%) Simple (%) p
Death 0.8 0.4 NS
MI 11.2 3.6 0.001
TVF 7.2 5.6 NS
Primary end point 15.2 8.0 0.009

The findings are consistent with those of other recent studies, including NORDIC, but at odds with the CACTUS trial, presented at the EuroPCR 2008 meeting, which showed no differences between provisional T-stenting and the crush technique. At the time, lead investigator Dr Antonio Colombo (Columbus Hospital, Milan, Italy) famously declared that there is "no advantage . . . but no penalization" to using the crush technique, a method he has championed in the past.

But Hildick-Smith believes the cards are stacking up against the two-stent techniques. "Clearly there was a 'penalization' in our study, and that's reflected in the high periprocedural MACE rate. Not only was there a high instance of MI and failure of total procedural success, but also in terms of complications while you were attempting to do that--pericardial effusion, tamponade, people needing to go to bypass. There were a few, and they were more [common] in the complex arm than in the simple arm. So that's another strike against the more complex strategy."

BBC ONE used the ESC/ACC 2000 definition of MI, namely troponin rise and ischemic symptoms, plus a "special-circumstances" definition for post-PCI (CK >3 times upper limit of normal 16 to 22 hours post-PCI) and for patients with MI on admission, a >50% further increase in CK.

Hildick-Smith clarified to heartwire that some of the MIs recorded in the trial were "major" while others were "CK bumps" during the procedure. Almost all of the periprocedural MIs reflected operator difficulties in the case report.

"The longer you're instrumenting the vessel, the more chance there is for thrombus or complications from multiple passages of wires and balloons, so distal embolization is an issue," he explained to heartwire . "If you're putting a stent into diseased lesions, then blowing it up to very high pressures to try to get an optimal bifurcation stent out of what is essentially a heavy metal crash, you will exert very high pressures on the walls of the vessels, and that may in itself cause enzyme leaks, either directly on the myocardium that you're compressing locally, or because it causes microembolization."

Further studies, he said, will need to look into the question of "whether there are bifurcation subsets in which total lesion coverage may be advantageous."

Hildick-Smith disclosed receiving grant/research support from Boston Scientific, Medtronic, and Abbott and consulting fees/honoraria from Medtronic, Cordis, Abbott, Boston Scientific, AGA Medical, NMT Medical, Gore Medical, BioSensors, and Terumo.


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