Intravascular Imaging Improves PCI Outcomes, Period

A high-quality, large-scale network meta-analysis found, yet again, that intravascular imaging to guide percutaneous coronary intervention (PCI) improves hard clinical end points. The results are definitive and strongly advocate for imaging-guided PCI.

The 2021 American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions (ACC/AHA/SCAI) guidelines for coronary artery revascularization give a class 2a recommendation to considering the use of intravascular ultrasound in patients with intermediate stenosis of the left main artery to help define lesion severity. Yet these already outdated guidelines stop short of recommending routine use of intracoronary imaging to guide and optimize PCI. In addition, the use of intracoronary imaging in clinical practice remains low, likely due to a combination of cost versus reimbursement calculations, perceived increase in procedural time, technical inexperience, and disbelief in the benefits. Some operators doggedly maintain a self-assured conviction of the superiority of their own angiographic estimations to guide PCI. Well, it may be time to change all that.

Kuno and colleagues performed a network meta-analysis of 32 randomized controlled trials investigating outcomes with intravascular imaging-guided, functionally guided, or angiography-guided PCI. In an analysis that included 22,684 patients, they compared the 3 approaches with respect to the primary outcome of trial-defined major adverse cardiovascular events (MACE), a composite of cardiovascular death, myocardial infarction (MI), and target lesion revascularization (TLR), as well as several secondary outcomes. Of the 32 trials, 19 studied PCI in the setting of acute coronary syndrome (ACS) and 13 were non-ACS trials. Mean follow-up ranged from 6 months to 5 years.

Compared with angiography-guided PCI, imaging guidance led to significant reductions in the risk for all major outcomes tested—MACE (relative risk [RR], 0.72; 95% CI, 0.62-0.82), cardiovascular death (RR, 0.56; 95% CI, 0.42-0.75), MI (RR, 0.81; 95% CI, 0.66-0.99), stent thrombosis (RR, 0.48; 95% CI, 0.31-0.73), and TLR (RR, 0.75; 95% CI, 0.57-0.99). The use of functional testing to guide PCI significantly reduced the risk of MACE (RR, 0.81; 95% CI, 0.69-0.96) and MI (RR, 0.78; 95% CI, 0.63-0.96) but not the risk of cardiovascular death, stent thrombosis, or TLR when compared with angiography guidance. While there were no significant differences in imaging versus functional guidance for the individual end points, intravascular imaging ranked best for MACE, cardiovascular death, stent thrombosis, and TLR. The supremacy of imaging guidance was consistent in both the ACS and non-ACS groups, though the benefit of imaging was exaggerated in the ACS trials.

The message here is clear and consistent with troves of prior data that strongly support the routine use of intravascular imaging to guide PCI. Improvements in hard end points across the board likely reflect improved stent sizing and optimization. In truth, maximizing the benefit from imaging guidance likely should entail both pre-PCI (to understand lesion morphology and determine appropriate treatment length and diameter) and post-PCI (to assess for edge dissections, stent-vessel apposition, and expansion) imaging. The implications of imaging “ranking” better than functional testing are unclear for practice. Intracoronary imaging and functional testing serve different purposes. The combination of functional testing to guide the decision to perform or defer PCI with imaging to guide and optimize PCI is likely the best approach moving forward.

The ACC/AHA/SCAI guidelines for coronary artery revascularization already give a strong class 1 recommendation for the use of functional testing with fractional flow reserve or instantaneous wave-free ratio to guide the decision to proceed with PCI. The results of this meta-analysis build on an already robust database and may very well catapult routine use of intracoronary imaging from a class 2a recommendation for the left main artery to a class 1 recommendation for any coronary artery. Reimbursement paradigms may need to shift in order to help drive practice change and improve patient outcomes. The results (should) speak for themselves.

Sources

Kuno T, Kiyohara Y, Maehara A, et al. Comparison of intravascular imaging, functional, or angiographically guided coronary intervention. J Am Coll Cardiol. 2023;82(23):2177-2178. doi:10.1016/J.JACC.2023.09.823

Lawton JS, Tamis-Holland JE, Bangalore S, et al. 2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2022. doi:10.1161/CIR.0000000000001038