In the first randomized trial of its kind in the era of new-generation drug-eluting stents (DES), stenting under IVUS guidance provided clinical benefit at 12 months compared with conventional angiographic guidance in patients with chronic total occlusions (CTOs).

After successful guidewire crossing, Yangsoo Jang, MD, PhD, of Yonsei University College of Medicine in Seoul, South Korea, and colleagues randomly assigned 402 patients with CTOs at 20 Korean centers to IVUS guidance (n=201) or angiographic guidance (n=201). In addition, IVUS-guided patients were randomized to implantation with Resolute zotarolimus-eluting stents (Medtronic) or Nobori biolimus-eluting stents (Terumo Medical).

At 12-month follow-up, the cumulative incidence of combined cardiac death, MI and target vessel revascularization (TVR; primary endpoint) was almost three-fold lower in the IVUS-guided group than the angiography-guided group (see Figure).

The rate of cardiac death or MI also was lower with IVUS (0% vs. 2%; P=.045), while TVR rates were equivalent between the groups (2.6% vs. 5.2%; P=.186).

Similarly, in a per-protocol analysis taking into account five patients (2.5%) who crossed over from IVUS to angiographic guidance and 35 (17.4%) who switched from angiographic to IVUS guidance, the primary endpoint was almost four-fold lower in the IVUS arm compared with the angiography arm (2.2% vs. 8.4%; P=.005). Again, both cardiac death or MI and TVR were reduced (0% vs. 2.3%; P=.019 and 2.2% vs. 6.1%; P=.049, respectively). The main reason for the crossover from IVUS was the failure of IVUS catheter passage. 

IVUS was also favored for the primary endpoint in multiple clinical and angiographic subgroups.

Lesion characteristics and post-dilatation differ

CTOs were defined as lesions with TIMI flow grade 0 and an estimated occlusion duration of at least 3 months. The reference vessel diameter ranged from 2.5 mm to 4 mm by operator assessment, and the total CTO length was no longer than 80 mm (average about 26.5 mm) with implantation of no more than four stents.

Baseline patient and CTO lesion characteristics were similar between the groups. Procedural success was nearly complete in both arms, with no differences in the total number of stents used, mean stent diameter or total stented length. However, the IVUS-guided group were more likely to receive high-pressure dilatation after stenting (51.2% vs. 41.3%; P=.045), with a higher maximum balloon pressure (14.6 ± 3.7 atm vs. 13.8 ± 3.8 atm; P=.04). Stenting resulted in a larger minimum luminal diameter in the IVUS group compared with the angiography group (2.64 ± 0.35 mm vs. 2.56 ± 0.41 mm; P=.025).

Despite limitations, a “great first step”

Jang acknowledged that the 12-month duration of follow-up is too short. In addition, he observed, although IVUS is also helpful in guidewire crossing, it was not used for that purpose in the trial because it is highly dependent on operator skill.

At a press conference, David G. Rizik, MD, of Scottsdale Healthcare Heart Group in Scottsdale, Ariz., commented: “One of the Achilles’ heels of CTO is the tendency to undersize the stent. This is a great first step in rolling IVUS into the routine algorithm for CTOs, and [these] results are very compelling.”

 Disclosures:

• Jang and Rizik report no relevant conflicts of interest.