The mechanical design of Medtronic’s new Resolute Integrity™ DES stems from a unique approach. “Most bare-metal stents are designed with forged links, like boxcars down a track,” Jones says. “They have hinge points that may not go around a curve in a smooth fashion. But this drug-eluting stent is a circular coil. It makes angulation easier.”
Dubbed “continuous sinusoid technology” by Medtronic, the coil is one continuous, single strand of wire molded into a sinusoidal wave and then wrapped in a helical pattern, making each stent comparable to a flexible spring.
“It tracks better through calcified and tortuous anatomy, which is not uncommon to find in diabetic patients,” says Joseph McGrath with Medtronic. The smoother connections of the Resolute Integrity DES also reduce the trauma caused by snaking a device through the often chronically inflamed arteries in diabetics.
Initially, Jones didn’t notice a difference in deliverability of the stent, but after reviewing the cases, he recognized its effectiveness. “I didn’t have the feeling that it was hugely better in deliverability when we first began using it, but in difficult cases it has been impressive to me,” Jones says. “When I asked it to do more, based on difficult arteries or disease, it’s done more.”
A previous disadvantage with Medtronic stents has also been addressed. The coil design has produced longer stents, up to 38mm. “Previously some of the Medtronic stents were not very long,” Jones says. “Now they’re fairly comparable to the competition, so that lessens the procedure time and the complexity of having to insert more than one.”
Though the Resolute Integrity DES utilizes a known drug — zotarolimus - the delivery system differs. “In other stents, the drug releases over 30 days. This one releases over 180 days,” Jones says. “I tell patients that the time frame to get through the healing phase is four to six months. And now this drug is delivered continuously for those entire six months.” This longer delivery time is advantageous for slow-healing diabetics.
“We also think the Resolute Integrity DES performed so well with diabetic patients because of the biocompatibility of the polymer,” McGrath says. “It mimics the surface of the red blood cell. So the body sees on the surface of the stent what looks like blood, and that prevents the aggregation of platelets that could eventually create a clot, especially in diabetics.”
“Diabetes is a big growing cardiac problem among patients in Alabama, so it was a no-brainer to bring in this stent,” says Jeff Green, director of invasive cardiac services at Trinity Medical Center.
Trinity became the first hospital in Alabama to use the Resolute Integrity™ DES with surgeons performing a percutaneous coronary intervention (PCI) almost immediately following its approval. In just the first six weeks of its availability, cardiologists at Trinity had inserted 71 stents. Since then, Brookwood Medical Center and Princeton Baptist have both begun using the stent as well.
To gain the FDA indication on the stent for diabetics, Medtronic pre-specified the subset analytics for diabetics in the study. “We agreed with the FDA in advance that we’d study diabetics as part of the protocol,” McGrath says. “Therefore since 30 percent of patients who undergo PCI have diabetes, we mirrored that percent in the Resolute study.”
The Resolute global clinical program had more than 5,100 PCI participants, 1,535 with diabetes, and consisted of a large randomized controlled trial and a series of confirmatory single-arm studies involving nearly 250 sites, with 128 of those in the U.S.
At the one-year of follow-up in the study conducted with U.S. patients, the results showed a low 4.7 percent rate of target lesion failure, 2.8 percent clinically-driven target lesion revascularization, and 0.1 percent definite/probable stent thrombosis. “A noticeable achievement, considering 34 percent of the patients in the study had diabetes, which typically drives higher event rates,” McGrath says.
“I’m conservative by nature, and it’s difficult for me to tout technology, one over the other,” Jones says. “But this stent has been able to deliver above my expectations and has the potential to provide a means of treatment for any or every situation that might occur in the cath lab. So far, there’s nothing I’ve been disappointed in.”
But Jones warns that it’s too early to judge accurately. “We’ve seen in years past a new technology that looks very favorable at first, but over a period of time, questions arose,” Jones says. “But then, this may well be, as we look back in another six months or two years, that this is one of those times we see a major shift in what we’re able to do.”
