Dr Eberhard Grube

According to Dr Eberhard Grube (Helios Heart Center, Siegburg, Germany), who presented the results here at the EuroPCR 2007 meeting, the data are "particularly encouraging" due to the length of lesions and the complexity of patients considered for inclusion in the CUSTOM II trial.

"It's fair to say that, given the complexity of the lesions we are tackling, I think these results are favorable, and we can be very optimistic for the future," he told heartwire."

The Custom NX stent has several unique design characteristics. Its chief distinguishing characteristic is its customizability: the stent is composed of multiple, interdigitated cobalt-chromium segments, each 6 mm in length, such that the length of stent can be custom-sized during a procedure, up to a maximum length of 60 mm, while being more flexible in tortuous vessels. It was also designed such that two lesions could be treated sequentially within a given vessel.

The drug used on the stent is Biolimus A9 (Biosensors International), a rapamycin derivative, applied only to the surfaces of the stent that contact the vessel wall; the polymer is bioerodable; and the delivery system includes a resizable balloon, allowing the operator to use a smaller balloon length for postdilatation, rather than reintroducing a separate balloon.

According to Grube, the ability to customize the length of the stent will help do away with many of the drawbacks of DES in longer lesions—namely, the problems of gaps, metal on metal, or doubling of dose or polymer in overlapping segments. "Right now, the best you can do is eyeballing, and up to 30% of the time you end up with a stent that is too short or too long. And then it adds complexity. As soon as you have a second stent to implant, all the issues of DES kick in. . . . The double-stent approach is definitely an advantage in terms of safety and in terms of reducing radiation, contrast, and so on," he said.

CUSTOM II is a single-arm study that enrolled a total of 100 patients: 69 with lesions greater than 20 mm and 31 with two lesions amenable to treatment with sequential stenting. Up to two customizable stent deployments of up to 60 mm were permitted in the study; patients were also required to have a minimum of three months of aspirin and clopidogrel. Mean lesion length in the long lesions was 31.68 mm and 25.16 mm in the two-lesion group, while total stent length was a mean of 44.18 mm in the long lesions and 30.48 mm in the two-lesion group.

At six months, MACE was 9%, with five deaths/MIs (two non-Q-wave) occurring in the hospital and four patients requiring target vessel revascularizations (TVR) over the next six months. In-stent late loss was 0.31 mm by angiography or intravascular ultrasound, and the binary restenosis rate at six months was 7.5%.

Grube stressed that the rate of in-hospital events was "not high" but "definitely concerning."

"The deaths in hospital are probably stent thrombosis, which will be adjudicated. We have to assume by [Academic Research Consortium] ARC definitions that it's stent thrombosis," he said.

"These long-term results demonstrate the safety of in situ customization to treat complex coronary lesions with a single catheter insertion," Grube concluded his presentation.

But Grube acknowledged to heartwire that long lesions requiring lengthy stenting have been fingered as one of the potential triggers for stent thrombosis with DES.

"Obviously the safety issue is an issue of time and an issue of short-, moderate-, and long-term follow-up data," he said. "The best thing we can say at this point is that we are very familiar with the technology: the bioresorbable polymer and the Biolimus have been out for basically two years now, so we have a platform that we have no reason to think is unsafe and two elements with which we have long-term experience. It seems a pretty safe concept. . . . Time will tell, but at least in the short term, we do not have any reason to believe there is a safety concern."

Commenting on the trial to heartwire, Dr Roxana Mehran (Columbia University, New York, NY) called the technology "very intriguing."

"The data are interesting. To have the ability to deploy a stent and then not have to overlap is just a very, very good concept," she told heartwire. "Even in the best scenarios, whenever we overlap there are issues: Have you got enough overlap? Too much overlap? Have you messed up the side branch? Obviously, they need to do prospective trials; this is very early, but we do know that their drug, Biolimus A9, is probably going to work based on the STEALTH trial."

There will, however, be a learning curve, she cautioned. "Interventionalists will have to get used to the concept of cutting and pasting and dropping off stent. It's very interesting but still too soon to know whether this will be as great as it seems. Time will tell."