The use of intravascular ultrasound (IVUS) to guide PCI leads to further improvements in event-free survival between one and two years post-procedure, according to a report from the ADAPT-DES study published in Circulation: Cardiovascular Interventions.
The nonrandomized trial initially looked at clinical outcomes after drug-eluting stent implantation in 8,582 consecutive PCI patients enrolled at 11 U.S. and German sites. Compared to PCI guided by angiography, procedures guided by IVUS were associated with lower one-year rates of stent thrombosis, myocardial infarction and major adverse cardiac events (MACE) including cardiac death, MI or stent thrombosis. With additional follow-up, the researchers sought to determine whether the gap in events associated with the different imaging approaches widened, narrowed or stayed the same between one and two years.
Two-year follow-up was completed for 3,059 patients with PCI guided by IVUS and 4,590 with angiography-guided PCI. Senior author Gregg W. Stone, MD, with New York-Presbyterian Hospital and Columbia University Medical Center in New York, and colleagues reported the following outcomes:
- MACE was reduced by 35 percent with IVUS compared to angiography at two years (4.9 percent versus 7.5 percent). One-year MACE rates were 3.2 percent versus 4.8 percent, respectively, while MACE occurred between years one and two in 1.9 percent of IVUS-guided PCI patients and 3.0 percent of angiography-guided patients.
- IVUS was associated with a lower rate of MI at two years (3.5 percent versus 5.6 percent) as well as between years one and two (1.1 percent versus 2.1 percent). Most of the gap was attributed to differences in target vessel MI.
- Although target vessel revascularization rates were similar at one year, a significant difference occurred between years one and two—1.8 percent in the IVUS group and 3.2 percent in the angiography group. That led to a statistically significant difference in target lesion revascularization at two years (5.0 percent versus 6.5 percent).
After multivariable adjustment, “IVUS guidance was independently associated with 60%, 35%, and 28% reductions of stent thrombosis, MI, and MACE at 2 years,” Stone and colleagues reported. “In the contemporary drug-eluting stent era, the benefits of intravascular ultrasound guidance not only continue but increase from 1 to 2 years, especially in reducing target vessel-related spontaneous myocardial infarction and late revascularization.”
The researchers calculated 41 patients would need to be treated with IVUS instead of angiography to prevent one MACE at two years, down from 64 patients at one year. They noted the relative reduction in MACE was consistent across complex lesion subsets—including left main, bifurcation, small vessels and long lesions—although the absolute benefit of IVUS was highest in more complex subsets due to higher overall event rates in those groups.
IVUS led to the operator changing the PCI strategy in 74 percent of cases, including choosing a larger stent or balloon in 37.7 percent of cases, changing the inflation pressure in 22.7 percent of cases and opting for a longer stent in 21.8 percent of procedures. In nearly 8 percent of interventions, the cardiologist decided to place an additional stent based on IVUS evaluation.
“Intravascular imaging modalities are entering a new era because the recently collected data seem to show new thresholds and targets for PCI planning and optimization,” two Italian cardiologists wrote in a related editorial. “Thus, IVUS and OCT (optical coherence tomography) are going to become the ideal glasses that interventional cardiologists should wear anytime something looks unclear before, during or after PCI.”
These techniques offer details beyond the capabilities of angiography, noted Francesco Burzotta, MD, PhD, and Carlo Trani, MD. But significant variation in the use of intravascular imaging exists across countries and between operators, which is only explained partially by reimbursement differences.
“Appropriate education, standardization of operative protocols and definitions of best clinical settings for application represent the future challenges for the intravascular imaging clinical implementation,” the editorialists wrote.