IVUS Guidance Beneficial for Diffuse Lesions in the Modern Stent Era
In the DES era, using IVUS instead of angiography alone to guide implantation seems to improve outcomes in patients with diffuse lesions, mostly due to a reduction in ischemia-driven TLR, a new meta-analysis of randomized trials shows.
The results, which were published online March 15, 2016, ahead of print in Circulation: Cardiovascular Interventions, are consistent with those of prior studies and suggest that more routine IVUS use should be considered for diffuse coronary lesions, the study authors say.
“We now have good data that IVUS guidance is beneficial, especially for diffuse lesions,” senior author Anthony Bavry, MD (University of Florida, Gainesville, FL), told TCTMD in an email. “The issue is not that more research is needed, but rather that this information needs to be embraced by the interventional community.”
When asked to comment on whether IVUS guidance should be the routine approach for DES implantation, John Hodgson, MD (Case Western Reserve University, Cleveland, OH), told TCTMD, “Absolutely.”
He pointed to the consistency of the evidence demonstrating the benefits of IVUS from single-center studies in the 1990s, meta-analyses conducted during the BMS era, meta-analyses incorporating observational data in the DES era, and now pooled randomized data in the DES era. The magnitudes of the event reductions have remained similar despite the fact that event rates have been falling overall, he noted.
“I believe that IVUS should be the standard and that the events that we’re preventing are significant enough events that it’s worth doing,” Hodgson said.
IVUS in the Era of DES
IVUS has been shown to be useful for optimizing stent implantation and has been associated with reductions of MACE and repeat revascularization—without an impact on death or MI—in the BMS era. However, because DES have lowered risks of restenosis and adverse events compared with BMS, some have questioned the utility of IVUS in the current era.
To help clarify the issue, lead author Islam Elgendy, MD (University of Florida), Bavry, and colleagues pooled trial-level data from seven RCTs that included a total of 3,192 patients with either stable coronary disease or ACS who underwent PCI with IVUS or angiographic guidance. Postdilatation was more frequently performed in the IVUS group (63% vs 47%; P < 0.0001), resulting in a larger minimum luminal diameter and reduced percent diameter stenosis after the procedure.
Patients were followed for a mean of 15 months, and during that time IVUS use was associated with lower risks of MACE, ischemia-driven TLR, TVR, and stent thrombosis, with nonsignificant trends toward reductions in cardiovascular mortality and MI.
Regarding cardiovascular mortality and MI, the authors say that “although improved stent apposition might be expected to decrease both of these outcomes, these were secondary outcomes with limited number of events, which reduced the power to detect a difference.”
Should IVUS Be Routine?
“By including the totality of data to date, this analysis showed the superiority of IVUS-guided PCI compared with angiography-guided PCI in the drug-eluting stent era,” the researchers write.
One explanation for the benefit is the more frequent use of postdilatation to optimize stent placement following IVUS, Elgendy told TCTMD in an email. “A larger postintervention cross-sectional area has been believed to be a major contributing factor for the prevention of restenosis after DES implantation,” he explained.
Based on the results of the meta-analysis, IVUS guidance should be the standard approach in patients with diffuse CAD, Elgendy said, noting that the mean lesion length in the pooled data was 32 mm. “Focal lesions may not benefit as much from IVUS,” he added.
Prior analyses also have supported use of IVUS guidance, but the technology is not yet used routinely for several reasons, including cost and lack of reimbursement, according to Elgendy.
In addition, “some operators may think that the visual assessment of the coronary lesions is sufficient,” he said. “However, it is well known that physician assessment of the severity of coronary lesions is variable and poorly correlates with myocardial ischemia.”
Perhaps for those reasons, an analysis of the National Cardiovascular Data Registry showed that IVUS was used in only about 20% of PCIs in the United States.
To Hodgson, the reluctance to use IVUS more widely is inexplicable. He said arguments that IVUS adds to procedure length, costs too much, is hard to interpret, or requires additional training do not hold water. “All of those things don’t make sense because physicians have adopted many other technologies that are far more difficult to learn, take a lot longer, or cost a lot more,” he said, estimating that IVUS is used in 85% to 90% of PCIs in Japan.
Hodgson said that more research likely will not convince physicians to adopt IVUS. “We continue to just make it known, try to help people become comfortable using it, integrate it more and more into the lab, make it easier to use,” he said, adding, “You can lead the horse to water, but you can’t make him drink it.”
“Hopefully people will be encouraged by these data and begin to offer patients the benefits that come from IVUS guidance,” he said.
- Elgendy IY, Mahmoud AN, Elgendy AY, et al. Outcomes with intravascular ultrasound-guided stent implantation: a meta-analysis of randomized trials in the era of drug-eluting stents. Circ Cardiovasc Interv. 2016;9:e003700.
- Bavry reports receiving an honorarium from the American College of Cardiology.
- Hodgson reports relevant relationships with Infraredx, Volcano, Boston Scientific, and St. Jude.
- Elgendy reports no relevant conflicts of interest.