Complete Coronary Revascularization in Patients with NSTEMI and Multi-vessel Coronary Artery Disease Undergoing PCI
When dealing with patients with multi-vessel coronary artery disease (CAD) it is intuitive and logical to accept that complete revascularization (CR) may be advantageous over incomplete revascularization (IR). In case of stable CAD, this concept of perceived advantage of CR over IR has been the impetus to perform CR where feasible in patients with multi-vessel CAD undergoing coronary artery bypass surgery (CABG)1. In fact, there were data from small studies which supported survival advantage with CR when compared to IR in patients who underwent CABG.1 This concept has been extrapolated to the patients undergoing percutaneous coronary intervention (PCI).2 More recently there have been series of randomized trials addressing this question in patients undergoing primary PCI for ST-elevation myocardial infarction (STEMI).3 For patients with NSTEMI who have multi-vessel CAD, retrospective observational data and post-hoc analyses lend some support for multi-vessel PCI.4, 5 However, no large randomized study has addressed this question directly in patients with Non-STEMI and this question remains unanswered. Moreover, amongst those patients where a decision has been made to perform multi-vessel PCI it is unknown whether this should be done in one sitting as in the case of CABG or on multiple sittings.
A recently published study, the SMILE (Impact of Different Treatment in Multivessel Non ST Elevation Myocardial Infarction Patients: One Stage Versus Multistaged Percutaneous Coronary Intervention) trial attempted to address this question.6 The aim of this study was to compare long-term outcomes in terms of major adverse cardiovascular and cerebrovascular events of two different CR strategies in patients with NSTEMI and multivessel CAD: One-stage PCI (1S-PCI) during the index procedure versus multistage PCI (MS-PCI) CR during the index hospitalization. In total, 584 patients were randomly assigned in a 1:1 manner to 1S-PCI or MS-PCI. The primary study endpoint was the incidence of major adverse cardiovascular and cerebrovascular events, which were defined as cardiac death, death, reinfarction, rehospitalization for unstable angina, repeat coronary revascularization (target vessel revascularization), and stroke at 1 year.
Somewhat surprisingly, the primary (composite) end point occurred more frequently in MS-PCI group (1S-PCI: n = 36 [13.63%] vs. MS-PCI: n = 61 [23.19%]; [HR]: 0.549 [95% CI]: 0.363 to 0.828; p = 0.004). This finding was attributable primarily to an unexpectedly higher rate of target vessel revascularization in the multistage group (8.3 versus 15.2%). When the analyses were restricted to harder end-points of death and myocardial infarction there was no significant difference between the groups. The authors concluded that in NSTEMI patients with multi-vessel CAD, complete 1-stage coronary revascularization is superior to multistage PCI in terms of major adverse cardiovascular and cerebrovascular events.6
There were a number of limitations including an open label design and composite end-point. The higher rate of target vessel revascularization in the multistage group was an unexpected finding which drove the difference in primary outcome.
It appears that single-stage multi-vessel PCI may be safe; however, the bigger question of complete vs incomplete revascularization remains unanswered in patient with multi-vessel CAD in context of NSTEMI.7, 8There is non-randomized and extrapolated data which supports such strategy but there is further need of large randomized trials. There are plenty of challenges making it difficult to design and undertake such trials. One of the main challenges is lack of universal definition of complete or incomplete revascularization.7 First and foremost is the difference between anatomic and functional/physiological revascularization. A contemporary definition of 3 different types of revascularization has been proposed and might be more relevant to modern clinical practice:7
(1) Complete anatomic revascularization, defined as treatment of all coronary artery segments >1.5 mm in diameter and ≥50% diameter stenosis;
(2) Anatomically incomplete but functionally adequate revascularization defined as treatment of all coronary segments with ≥50% diameter stenosis supplying viable myocardium; and
(3) Incomplete functional revascularization consequentially, defined as the inability to treat all coronary segments that supply viable myocardium and have a >50% diameter stenosis.
In conclusion, complete revascularization in patients with NSTEMI undergoing PCI may be superior to incomplete revascularization and this can safely performed as one-stage PCI procedure.6 Large randomized trial which take into account both the anatomical and physiology when defining multi-vessel CAD are required to conclusively guide the practice.
References & Further Readings
1. Lawrie GM, Morris GC, Jr., Silvers A, Wagner WF, Baron AE, Beltangady SS, Glaeser DH, Chapman DW. The influence of residual disease after coronary bypass on the 5-year survival rate of 1274 men with coronary artery disease. Circulation. 1982;66:717-723
2. Garcia S, Sandoval Y, Roukoz H, Adabag S, Canoniero M, Yannopoulos D, Brilakis ES. Outcomes after complete versus incompleterevascularization of patients with multivessel coronary artery diseasea meta-analysis of 89,883 patients enrolled in randomizedclinical trials and observationalstudies. Journal of the American College of Cardiology. 2013;62:1421-1431
3. Kowalewski M, Schulze V, Berti S, Waksman R, Kubica J, Kolodziejczak M, Buffon A, Suryapranata H, Gurbel PA, Kelm M, Pawliszak W, Anisimowicz L, Navarese EP. Complete revascularisation in st-elevation myocardial infarction and multivessel disease: Meta-analysis of randomised controlled trials. Heart. 2015;101:1309-1317
4. Shishehbor MH, Lauer MS, Singh IM, Chew DP, Karha J, Brener SJ, Moliterno DJ, Ellis SG, Topol EJ, Bhatt DL. In unstable angina or non-st-segment acute coronary syndrome, should patients with multivessel coronary artery disease undergo multivessel or culprit-only stenting? J Am Coll Cardiol. 2007;49:849-854
5. Rosner GF, Kirtane AJ, Genereux P, Lansky AJ, Cristea E, Gersh BJ, Weisz G, Parise H, Fahy M, Mehran R, Stone GW. 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
6. Sardella G, Lucisano L, Garbo R, Pennacchi M, Cavallo E, Stio RE, Calcagno S, Ugo F, Boccuzzi G, Fedele F, Mancone M. Single-staged compared with multi-staged pci in multivessel nstemi patients: The smile trial. J Am Coll Cardiol. 2016;67:264-272
7. Zimarino M, Calafiore AM, De Caterina R. Complete myocardial revascularization: Between myth and reality. European heart journal. 2005;26:1824-1830
8. Ong AT, Serruys PW. Complete revascularization: Coronary artery bypass graft surgery versus percutaneous coronary intervention. Circulation. 2006;114:249-255