Completeness of Revascularization Matters

Abstract & Commentary

By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco. Dr. Boyle reports no financial relationships relevant to this field of study.

Source: Farooq V, et al. The negative impact of incomplete angiographic revascularization on clinical outcomes and its association with total occlusions: The SYNTAX (Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) trial. J Am Coll Cardiol 2013;61:282-294.

During coronary artery bypass graft (CABG) surgery, the aim is to achieve complete revascularization of all the coronary arteries. However, with percutaneous coronary intervention (PCI), there is debate regarding whether we should revascularize only the “culprit” vessel or whether we should aim for complete revascularization. Farooq and colleagues addressed this issue by examining the SYNTAX trial database and studying the effects of incomplete revascularization (ICR) vs complete revascularization (CR) on the long-term clinical outcomes. In addition, they explored the effects of chronic total occlusions (CTOs) of coronary arteries on these outcomes.

The SYNTAX program consisted of a randomized, controlled trial of CABG vs PCI in patients with multivessel coronary artery disease (CAD) or left main disease, and nested registries of PCI and CABG that enrolled patients who were not randomized. The authors performed a post-hoc study, consisting of patients in the randomized SYNTAX trial (n = 1800) and the nested PCI (n = 198) and CABG (n = 649) SYNTAX registries. They analyzed 4-year clinical outcomes in patients with and without angiographic CR, in the PCI and CABG arms, and also for patients with and without CTOs in both study arms.

Angiographic CR was achieved in 53% of the PCI arm and 67% of the CABG arm. Within the PCI and CABG arms, ICR (compared with CR) was associated with higher rates of clinical comorbidities and more anatomically complex CAD. ICR was also associated with significantly higher frequencies of 4-year mortality, all-cause revascularization, and major adverse cardiac and cerebrovascular events (MACCE) in both the CABG and PCI arms, as well as less stent thrombosis in the PCI arm.

The presence of a CTO was the strongest independent predictor of ICR after PCI (hazard ratio 2.70, P < 0.001). Eight hundred and forty patients (PCI 26.3%, CABG 36.4%; P < 0.001) were identified to have 1007 CTOs. The findings associating ICR (compared with CR) with higher frequencies of 4-year mortality and major adverse cardiac and cerebrovascular events remained consistent in the CTO groups in the PCI and CABG arms. The authors conclude that within the PCI and CABG arms of the all-comers SYNTAX trial, angiographically determined ICR has a detrimental impact on long-term clinical outcomes, including mortality, and this effect remained consistent in patients with and without CTOs.

Commentary

There is mounting evidence that CR is associated with better clinical outcomes. While it has long been the standard in CABG that we should aim for the most complete revascularization possible, in treating patients with PCI there is debate between aiming for CR and the “less is more” approach of treating only the culprit lesion. The results of this paper are consistent with other recent post-hoc analyses of randomized trials. In the BARI 2D trial, patients with type 2 diabetes mellitus and less CR had more long-term cardiovascular events.1 In the ACUITY trial of patients undergoing PCI for acute coronary syndromes, depending on the threshold used, incomplete revascularization was present in 17-75% of patients with ACS after PCI. Regardless of the threshold, incomplete revascularization was strongly associated with 1-year MI, ischemia-driven unplanned revascularization, and MACE.2 Other studies have discussed “reasonable” ICR for vessels that are small or subtend small areas of ischemic potential. It is important to note that these studies are all post-hoc analyses, and are therefore subject to bias. Whether an upfront strategy of attempting CR in all patients at all times is warranted remains unknown, and should be tested in prospective randomized trials. However, I think that will be difficult to achieve. For now, these data will not change clinical practice guidelines. Each case should be assessed and treated on its merits. If a more complete revascularization strategy can be achieved without significant increase in patient risk, then it may be reasonable to aim for CR.

References

1. Schwartz L, et al. Impact of completeness of revascularization on long-term cardiovascular outcomes in patients with type 2 diabetes mellitus: Results from the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D). Circ Cardiovasc Interv 2012;5: 166-173.

2. Rosner GF, et al. Impact of the presence and extent of incomplete angiographic revascularization after percutaneous coronary intervention in acute coronary syndromes: The Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial. Circulation 2012;125:2613-2620.