Seeing is Believing, Especially for Percutaneous Coronary Intervention

Investigators show that utilization of intravascular imaging (IVI) to guide percutaneous coronary intervention (PCI) improves outcomes…again¹. Yet, despite consistent evidence, utilization of imaging guidance remains low.

Ample data support the use of either intravascular ultrasound (IVUS) or optical coherence tomography (OCT) to guide PCI over angiography alone². While angiography remains foundational for interventional cardiology, it is susceptible to intra- and inter-observer variability as well as two-dimensional extrapolation to a three-dimensional truth. In contrast, adjunctive IVI can standardize an objective approach to pre-stenting lesion characterization, peri-stenting planning, and post-stenting optimization. Both randomized controlled trials and several meta-analyses have repeatedly demonstrated improved outcomes when PCI is guided by IVI with reductions in target lesion failure, target vessel revascularization, cardiovascular mortality, stent thrombosis, and other MACE events. And yet, adoption of IVI remains low in practice.

The RENOVATE COMPLEX-PCI trial provides additional evidence in support of IVI-guided PCI. This is an investigator-initiated, prospective, multicenter, randomized, open-label trial conduced at 20 sites in South Korea. Patients with complex coronary artery lesions undergoing PCI were randomized in a 2:1 fashion to either IVI-guided PCI or angiography-guided PCI. The primary endpoint was a composite of cardiac death, target vessel-related myocardial infarction (MI), or clinically driven target vessel revascularization. Operators could use IVUS or OCT at their discretion in the IVI group.

A total of 1639 patients underwent randomization (1092 in the IVI group and 547 in the angiography only group). The typical patient was a man in his 60s with preserved left ventricular ejection fraction and excellent background medical therapy (age 65.6 +/- 10.2 years, 79.3% male, LVEF 58.7 +/- 11.6%, statin use in 95.6%). Importantly, race is not disclosed in Table 1. The breakdown is stable ischemic heart disease versus acute coronary syndromes was approximately 50/50.

Target lesion characteristics in this intentionally complex PCI cohort included true bifurcations (21.9%), chronic total occlusions (19.5%), unprotected left main coronary disease (11.7%), diffuse long lesions (54.8%), multivessel PCI involving ≥2 arteries (37.9%), placement of ≥3 stents (18.6%), lesions with in-stent restenosis (14.4%), heavily calcific lesions (14.1%), ostial lesions (15.3%) and ≥3 complex coronary lesions (30.8%). In the IVI group, 98.7% actually used an imaging device (74.2% IVUS and 25.8% OCT). In the angiography-guided PCI group, 2.4% used an imaging device (all IVUS). Still, comparisons were made as intention-to-treat analyses.

Over a median follow-up of 2.1 years, a primary endpoint had occurred in 7.7% of patients randomized to the IVI-guided PCI versus 12.3% of patients randomized to angiography-guided PCI (hazard ratio, 0.64; 95% CI, 0.45-0.89; P = 0.008). Positive secondary endpoints included target vessel failure without procedure related MI (5.1% vs 8.7%; HR, 0.59; 95% CI, 0.39-0.90), target vessel related MI or death from cardiac causes (5.3% vs 8.5%; HR, 0.63; 95% CI 0.42-0.93), and cardiac death (1.7% vs 3.8%; HR, 0.47; 95% CI, 0.24-0.93). All-cause mortality, target-vessel related MI, repeat revascularization, stent thrombosis, and contrast induced nephropathy were no different between the two groups as individual endpoints. Median procedure time was longer in the IVI group (70 vs 53.5 min).

Consistent with the preponderance of historical data, the current study adds additional and resounding support for the use of IVI-guidance for complex PCI to improve outcomes. The reason for this is probably related to improved stent sizing, stent optimization, and recognition of adverse features warranting additional attention (stent mal-apposition, edge dissection, residual disease, etc). Not surprisingly, use of IVI resulted in more frequent use of additional stent post-dilation and larger mean stent area (2.8+/-0.5mm vs 2.7+/-0.5mm).  Of note, while pre-procedure planning is a valuable element of IVI-guided PCI, the protocol did not mandate use of IVI prior to stenting and as such in 23.6% of lesions within the IVI group, IVI was performed after PCI only.

The message is clear. Time and again, studies have shown that using intravascular imaging to guide percutaneous coronary intervention improves hard outcomes, especially for more complex disease. Yet utilization remains low, both in practice and in contemporary PCI trials. Reasons for slow adoption include operator unfamiliarity, concerns about procedure time, and reimbursement paradigms. Accelerating integration will require a multipronged approach including operator training, improved reimbursement, and increased awareness on the part of both referring clinicians and patients.

References

1. Lee JM, Choi KH, Song Y Bin, Lee J-Y, Lee S-J, Lee SY, Kim SM, Yun KH, Cho JY, Kim CJ, Ahn H-S, Nam C-W, Yoon H-J, Park YH, Lee WS, Jeong J-O, Song PS, Doh J-H, Jo S-H, Yoon C-H, Kang MG, Koh J-S, Lee KY, Lim Y-H, Cho Y-H, Cho J-M, Jang WJ, Chun K-J, Hong D, Park TK, Yang JH, Choi S-H, Gwon H-C, Hahn J-Y. Intravascular Imaging–Guided or Angiography-Guided Complex PCI. N Engl J Med. 2023;
2. Truesdell AG, Alasnag MA, Kaul P, Rab ST, Riley RF, Young MN, Batchelor WB, Maehara A, Welt FG, Kirtane AJ. Intravascular Imaging During Percutaneous Coronary Intervention: JACC State-of-the-Art Review. J Am Coll Cardiol [Internet]. 2023;81:590–605. Available from: https://doi.org/10.1016/j.jacc.2022.11.045