Journal of Invasive Cardiology

Recently, I was lucky enough to experience the excellent international interventional cardiology conference run by James Margolis MD in Snowmass, Colorado. For me, one of the most interesting talks related to the use of IVUS. J.S Park from South Korea presented very interesting data from the MAIN-COMPARE registry1 showing that IVUS guidance for left-main procedures using DES can have a profound impact on mortality. The risk of 3-year mortality was 60% lower in the IVUS arm versus angiography (Figure 1). Other studies such as Roy et al2 have also proposed that IVUS guidance during PCI may reduce the rate of DES thrombosis. Compared with angiography, IVUS has the unique ability to assess suboptimal results of stenting, which may be associated with the occurrence of stent thrombosis. Previously, IVUS evaluations of stent under-expansion, incomplete lesion coverage, small stent areas, large residual plaque, and poor apposition have been found to predict stent thrombosis after DES placement.3–5

You can therefore imagine my dismay, when the talk that followed highlighted the next big randomized Stent vs. Surgery trial called EXCEL (Evaluation of Xience Prime versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization). This trial will be powered to assess the best treatment of left main disease, given the interesting results in this sub-group of the SYNTAX trial. In EXCEL, 2,500 patients will have follow up to a mean of three years examining a primary endpoint of death, MI and stroke (notably missing out the Achilles heel of PCI-TVR). However, IVUS guidance of left main PCI will not be a mandatory part of the protocol!

Hang on a minute! If your ultimate aim is to finally see the surgeons lose the “SOS — Stent or Surgery” battle, why deliver a devastating blow by negotiating the removal of TVR from the endpoints and not follow it up with the punishing uppercut of a potential 60% decrease in mortality with IVUS guidance? I just don’t understand the logic! I am sure there must be a reason and I would be very grateful for anyone with greater insight, experience or inside information, kindly posting a reply to this blog. I truly believe that as a community we have ignored IVUS guidance for too long. Primarily, this has been because of cost and the results from under-powered, non-randomized, flawed trials of IVUS guidance in the late 90s.

If we want to do the job to the best of our ability, we must embrace imaging techniques such as IVUS and OCT and fully deploy physiological assessment in the form of FFR. Imagine what may have happened had the SYNTAX trial incorporated “FAME-like” FFR lesion assessment and quality IVUS optimisation of the final results. (using the Xience stent) Surely this would have been a better example of how to EXCEL in contemporary coronary intervention.

References
1. Seung-Jung Park, MD, PhD*; Young-Hak Kim, MD, PhD*; Duk-Woo Park, MD, PhD; Seung-Whan Lee, MD, PhD; Won-Jang Kim, MD, PhD; Jon Suh, MD; Sung-Cheol Yun, PhD; Cheol Whan Lee, MD, PhD; Myeong-Ki Hong, MD, PhD; Jae-Hwan Lee, MD, PhD; Seong-Wook Park, MD, PhD; for the MAIN-COMPARE Investigators. Impact of Intravascular Ultrasound Guidance on Long-Term Mortality in Stenting for Unprotected Left Main Coronary Artery Stenosis.
Circ Cardiovasc Intervent. 2009;2: 167-177.

2. Probal Roy, Daniel H. Steinberg, Steven J. Sushinsky, Teruo Okabe, Tina L. Pinto Slottow, Kimberly Kaneshige, Zhenyi Xue, Lowell F. Satler, Kenneth M. Kent, William O. Suddath, Augusto D. Pichard, Neil J. Weissman, Joseph Lindsay and Ron Waksman. The potential clinical utility of intravascular ultrasound guidance in patients undergoing percutaneous coronary intervention with drug-eluting stents
Eur Heart J (2008) 29 (15): 1851-1857

3. Okabe T, Mintz GS, Buch AN, Roy P, Hong YJ, Smith KA, Torguson R, Gevorkian N, Xue Z, Satler LF, Kent KM, Pichard AD, Weissman NJ, Waksman R. Intravascular ultrasound parameters associated with stent thrombosis after drug-eluting stent deployment. Am J Cardiol. 2007;100:615–620.

4. Sonoda S, Morino Y, Ako J, Terashima M, Hassan AHM, Bonneau HN,
Leon MB, Moses JW, Yock PG, Honda Y, Kuntz RE, Fitzgerald PJ.
Impact of final stent dimensions on long-term results following sirolimus eluting
stent implantation: serial intravascular ultrasound analysis from
the sirius trial. J Am Coll Cardiol. 2004;43:1959 –1963.

5.Fujii K, Carlier SG, Mintz GS, Yang Y-m, Moussa I, Weisz G, Dangas G, Mehran R, Lansky AJ, Kreps EM, Collins M, Stone GW, Moses JW, Leon MB. Stent underexpansion and residual reference segment stenosis are related to stent thrombosis after sirolimus-eluting stent implantation: an intravascular ultrasound study. J Am Coll Cardiol. 2005;45:995–998.

Figure 1. Kaplan–Meier incidence curves of the outcomes following IVUS and angiography guidance in 145 propensity matched pairs of patients receiving drug eluting stents

Scott Murray is currently employed as a Specialist Registrar in Cardiology at The Liverpool Heart and Chest Hospital NHS Foundation Trust, U.K. His main interest is coronary intervention and atherosclerosis imaging and he is currently P.I for an observation study using Intravascular Ultrasound: The Liverpool V-HEART study – Virtual Histology Evaluation of ACS Requiring Treatment. He hopes to provide the journal with a light-flavour of Cardiology musings from across the pond.