SPIRIT 48: Long DES for Diffuse CAD Highly Deliverable, Safe at 1 Year

PHOENIX, AZ—In patients with diffuse CAD, a next-generation, longer-length stent may eliminate the need for multiple overlapping devices for treating long, continuous plaques, according to results from the SPIRIT 48 trial.

“One of the rationales for doing this was that long lesions are difficult to treat,” Ki Park, MD, MS (University of Florida, Gainesville), told TCTMD. Cutting back on the number of stents needed may limit restenosis risk while also providing better lesion coverage than the full-metal-jacket approach, she added.

The study tested the safety and efficacy of the everolimus-eluting Xience Skypoint 48 (Abbott), which is not yet approved in the United States. Currently, longer-length stents are in limited supply for operators, with the only US Food and Drug Administration-approved 48-mm coronary stent being the Synergy XD (Boston Scientific).

“One of the first things I thought of when I was approached about being PI of this study was the deliverability of the stent because it's significantly longer than the prior iterations of Xience, which are 38 millimeters,” Park added. “We did find that the device success rate was high and so we decided it was deliverable, which I think is a favorable feature for operators.”

In her presentation at the Society for Cardiovascular Angiography and Interventions (SCAI) 2023 Scientific Sessions, Park showed that the primary endpoint of target lesion failure—defined as a composite of cardiac death, target vessel-related MI, and clinically indicated TLR at 1 year—occurred in 5.7%, with a confidence interval upper bound of 9.5%, well below the performance goal of 20% (P < 0.0001).

While the mean target lesion length was 35.19 mm, a dozen patients in the study had a target lesion that was longer than 44 mm in the single-arm, multicenter study.

“I'm rather surprised that with these long lesions and long stents, you had such great outcomes,” said session co-moderator Cindy Grines, MD (Northside Hospital Cardiovascular Institute, Atlanta, GA), who questioned whether that might stem from newer technology or the elimination of overlapping stents.

“There's no comparator group, so it's hard to make that sort of assessment,” Park said. “Nowadays, the rates of overall TLF with our contemporary drug-eluting stents are quite low, and so this is an extension of what we know from our prior iteration of drug-eluting stents [extrapolating] to a longer platform.

“But I do feel,” she continued, “that it does reduce the need for multiple overlapping stents, which is known to be associated with increased risk of stent failure in the long term.”

The study was simultaneously published in JSCAI.

SPIRIT 48 Results

The trial enrolled 105 patients (mean age 67.3 years; 27.6% women) at 25 sites in three countries. Most had stable angina, with the left anterior descending (LAD) artery being the target vessel in more than 50%. The average body mass index was 29 kg/m2, approximately 50% of patients were current or former tobacco users, and more than 80% had a history of hypertension and dyslipidemia, with diabetes in 34%. Moderate-to-severe calcification was present in approximately 47% of patients.

The in-device percentage of diameter stenosis was 11.96% and the in-device mean minimum lumen diameter was 2.44 mm. The rate of device success was 97.2% and the procedural success rate was 93.4%.

The TLF results were consistent across all prespecified subgroups. Target-vessel MI occurred in about 5% of patients, cardiac death and clinically indicated TLR occurred in 1%, and TLF as evaluated by multiple definitions of MI ranged from 4% to 6%. Rates of all death, all MI, and all revascularization ranged from 5% to 6%, while just one patient had a definite stent thrombosis.

Following the presentation, Grines asked how operators in the study managed the anatomical tapering of the long lesion diameters: “Did you deploy it at a low pressure so you could post-dilate distally with a different size compared to proximally?”

In response, Park noted that imaging was not mandated as part of the study, which is a limitation.

While some study operators did use intracoronary imaging, data on actual usage was not routinely collected, she noted. What’s more, Park said the SPIRIT 48 experience led the trialists to recommend that operators use guide-extension-assisted stent implantation going forward.

“It wasn't mandated, so we don't have that data,” she noted. “But it’s something that we think should be considered because it is a significantly longer stent.”