AVIO: IVUS-Guided Stent Implantation Results in Greater Postprocedure Minimal Lumen Diameter

September 29, 2010

Dr Antonio Colombo

September 29, 2010 (Washington, DC) — The use of intravascular ultrasound (IVUS) to guide drug-eluting-stent implantation in complex lesions results in a larger minimal lumen diameter (MLD) when compared with angiography-guided stent implantation, according to the results of a new study. Clinically, however, at 30 days and nine months, there was no significant difference in the combined end point of MI, target lesion revascularization (TLR), target vessel revascularization (TVR), and cardiac death.

Presenting the results of the study, known as the AVIOtrial, during the late-breaking clinical-trials session at TCT 2010 , lead investigator Dr Antonio Colombo (Columbus Hospital, Milan, Italy) said the trial established definite criteria for optimal stent expansion.

The AVIO investigators treated patients with complex lesions, such as those with lesion lengths >28 mm, chronic total occlusions, bifurcation lesions, small vessel lesions, or multiple lesions requiring four or more stents. In total, 142 patients in each arm were randomized to IVUS-guided and angiography-guided stent implantation, respectively. Regarding the primary end point, patients implanted with a stent guided by IVUS had significantly greater postprocedure in-lesion MLD evaluated by coronary angiography.

AVIO: Primary and Secondary End Points

End point IVUS-guided implantation Angiography-guided implantation p
Postprocedure MLD (mm), primary end point 2.70 2.51 0.0002
In-lesion acute gain (mm) 1.93 1.87 0.31
Freedom from MACE (MI, TLR, TVR, and cardiac death) at 9 mo (%) 85.9 83.1 0.47

Importantly, Colombo and colleagues showed that postprocedure MLD was significantly greater in 75 lesions treated with IVUS meeting the criteria for optimal stent placement, while MLD was not significantly different between the IVUS-guided and angiography-guided treatment arms when operators were unable to optimize the placement of the stent.

"It's interesting that not all the centers were able to optimize the lesion according to the criteria," said Colombo. "Here, we see 75 lesions where the criteria were met and 81 lesions where the criteria could not be met. Again, when the criteria are met, the final MLD goes from 2.51 mm [angiography-guided] to 2.86 mm [IVUS-guided], but when the criteria aren't met, the MLD is 2.51 mm and 2.6 mm, respectively, which kind of makes sense."

Limited Angiographic Follow-Up

Colombo said there was no support for follow-up angiography and that just 39% of patients had quantitative coronary angiography at nine months. As a result, the investigators are unable to make any statements about the benefits of IVUS-guided stent implantation on restenosis rates.

Dr David Kandzari

Commenting on the study results during the late-breaking trial panel discussion, Dr David Kandzari (Piedmont Heart Institute, Atlanta, GA) said clinicians have likely sold themselves short in the past few years when drug-eluting stents came on the market. The thinking, he said, was that they didn't need to achieve the same postprocedure MLD as with bare-metal stents, but "this has come back to haunt us a little bit, both in safety and failure of efficacy." Evidence also suggests that IVUS is associated with improved survival in left-main disease, he added.

Kandzari, who uses IVUS at some stage of the intervention in approximately 80% of his cases, said that most operators probably do not use the technology as frequently and would be unlikely to meet the quantitative and qualitative criteria set out for determining optimal stent expansion. It raises the question, he said, whether repetitive high-pressure balloon angioplasty might also be effective for obtaining better stent placement. Dr George Dangas (Mount Sinai Medical Center, New York), like other discussants, said it is necessary to know whether IVUS-guided stent placement in these complex lesions translates into improved long-term clinical outcomes.


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