There remains considerable discussion as to the appropriate roles of bare-metal stents (BMS) and drug-eluting stents (DES) in optimal percutaneous revascularization. Competing themes include the lower restenosis rates particularly in later-generation DES with less concern for stent thrombosis and potentially shorter use of DAPT in patients at higher risk for bleeding. But, in contrast, BMS have also continued to improve with thinner struts and potential advantages for very short duration DAPT in special-risk patients, such as those on antithrombin therapy with atrial fibrillation. Last month in this collection's poll, the respondents reflected this diversity of opinion, as did the results of the NORSTENT trial that randomized over 9,000 patients to "modern" DES and BMS that was presented at the 2016 ESC Congress in Rome. After 5-year follow-up, there was no difference in the risk of death combined with non-fatal, spontaneous myocardial infarction, although there was a lower rate of recurrent revascularization in the DES group (see Bønaa KH, Mannsverk J, Wiseth R, et al. Drug-eluting or bare-metal stents for coronary artery disease. N Engl J Med 2016;375:1242-52).

To better understand the issues and opinions involved in the continued discussion of the relative benefits of each stent class, we invited Dr. Michael P. Thomas and Dr. Antonio Colombo to create a set of "Pro-Con" articles representing the extreme positions. Their opinions offer an excellent opportunity to provide science for the passion.

George W. Vetrovec, MD, MACC
Editorial Lead of the Invasive CV Angiography and Interventions Clinical Topic Collection

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The development of coronary stents greatly improved the outcomes and safety of percutaneous coronary intervention (PCI). The limitation of bare-metal stents (BMS) was restenosis and need for repeat target lesion revascularization (TLR), which was reduced with drug-eluting stents (DES). However, the delay in vessel healing associated with DES was associated with increased rates of late stent thrombosis and the requirement for longer duration dual antiplatelet therapy (DAPT). Recent developments in stent technology have led to DES being preferred in most clinical situations and requiring shorter duration DAPT; however, BMS technology has also improved, and BMS remain an important stent option in PCI for patients with 1) large vessel diameter, 2) inability to complete the recommended duration of DAPT, 3) inability to pay for DES, and 4) increased bleeding risk.

Large Vessel Diameter

The benefit of DES in smaller vessels is attenuated in large diameter vessels (3.5 mm or greater) where restenosis is less of a problem and the number needed to treat to prevent one target vessel revascularization (TVR) is much larger, especially with shorter lesions. Steinberg and colleagues examined outcomes at 30 days, 6 months, and 1 year in 233 patients with DES in vessels at least 3.5 mm diameter and compared them with 233 propensity-matched patients receiving BMS.¹ There were no differences in TLR, TVR, or major adverse cardiovascular events, leading the authors to conclude that there was no benefit for DES in large diameter vessels. BASKET (Basel Stent Cost-Effectiveness Trial) investigators randomized 826 patients in a 2:1 fashion to first-generation DES versus BMS.² The composite endpoint was cardiac death, myocardial infarction (MI), and non-MI TVR at 18 months, analyzed for stent type and patient and vessel characteristics. TVR rates were similar for stents >3 mm (hazard ratio = 0.75; p = 0.38), and cardiac death and MI rates increased after DES implantation in larger vessels (hazard ratio = 2.07; p = 0.05). Three-year follow-up of BASKET demonstrated no difference in 3-year TVR (9.5% with BMS vs. 11.5% with DES; p = 0.44) and an increase in late death and MI in patients with larger DES (9.7 vs. 3.1%; p = 0.006).³ The similar TVR outcomes for DES and BMS, as well as increased cardiac death and MI rates with DES in larger vessels, was further investigated in BASKET-PROVE (Basel Stent Cost-Effectiveness Trial—Prospective Validation Examination) in an effort to determine whether these outcomes were similar for second-generation DES.⁴ The study randomized 2,314 patients to DES or BMS in vessels >3 mm. There was no significant difference in the primary composite endpoint of death from cardiac causes or nonfatal MI at 2 years. The secondary endpoint of TVR was lower with DES.

Premature Discontinuation of DAPT

Premature discontinuation of DAPT is the major risk factor for stent thrombosis. In PREMIER (Prospective Registry Evaluating Myocardial Infarction: Events and Recovery), among 500 DES-treated patients with MI who were discharged on DAPT, 68 (13.6%) stopped therapy within 30 days.⁵ They were older, less likely to have completed high school or be married, more likely to avoid health care because of cost, and more likely to have had preexisting cardiovascular disease or anemia at presentation. They were also less likely to have received discharge instructions about their medications or a cardiac rehabilitation referral. Importantly, they were more likely to die during the next 11 months (7.5 vs. 0.7%; p < 0.0001) and to be rehospitalized (23 vs. 14%; p = 0.08).

The second most common reason for discontinuation of DAPT is the need for noncardiac surgery within 1 year of stent implantation.⁶ This occurs in 4% of patients and increases the risk for periprocedural MI from stent thrombosis.

The 2011 ACCF/AHA/SCAI guidelines on PCI stated that first-generation DES should not be implanted if the patient was not likely to be able to tolerate and comply with prolonged DAPT or if this could not be determined before stent implantation (Class III, Harm).⁷ It also recommended that balloon angioplasty or BMS should be used in patients with high bleeding risk, inability to comply with 12 months of DAPT, or anticipated invasive or surgical procedures within the next 12 months, during which time DAPT may be interrupted (Class I). The 2016 ACC/AHA Guideline Update on the duration of DAPT in patients with stable ischemic heart disease gave a Class I recommendation for 6-12 months of DAPT after elective second-generation DES implantation, but only 1 month after BMS implantation (Class I).⁸ Elective noncardiac surgery should be delayed 30 days after BMS implantation and optimally 6 months after DES implantation (Class I). Surgery may be considered 3 months after DES implantation if the risk of further delay is greater than the expected risks of stent thrombosis (Class IIb). Therefore, BMS should remain the treatment of choice in patients who can take DAPT only for a limited duration.

DES Expense

The procurement cost of DES is twice that of BMS.⁹ In hospitals where cost containment is critical, DES may be reserved for those lesions that are at high risk of restenosis (diabetes, bifurcation lesions, small diameter), with the first-line use of BMS for other lesions to contain cost. Furthermore, BMS are attractive options in areas of the world where patients are required to pay the cost of their medical procedures.

Increased Bleeding Risk

Patients with recent bleeding are poor candidates for longer duration DAPT. Additionally, longer duration DAPT may place other patient subgroups, such as elderly patients, at an unacceptably high bleeding risk. The XIMA (Xience or Vision for the Management of Angina in the Elderly) trial enrolled 800 patients at least 80 years of age and randomized them to either BMS or DES.¹⁰ Acute coronary syndrome was present in 68%, and 32% had stable angina. The primary endpoint was a composite of death, MI, stroke, TLR, or major hemorrhage. The rates of DAPT at 1 year were 32.2% in the BMS group and 94% in the DES group; there was no significant difference in the primary endpoint between the groups (BMS = 18.7%, DES = 14.3%; p = 0.09).

The optimal antiplatelet regimen after stenting for patients taking oral anticoagulants continues to be investigated. Approximately 6-8% of patients undergoing stent implantation have an indication for anticoagulation including atrial fibrillation, mechanical prosthetic valves, left ventricular thrombus, or pulmonary embolism.¹¹ The WOEST (What is the Optimal Antiplatelet and Anticoagulant Therapy in Patients with Oral Anticoagulation and Coronary Stenting) trial randomized patients to clopidogrel and warfarin following stent implantation versus triple therapy (aspirin, clopidogrel, and warfarin) and found that those taking clopidogrel and warfarin had lower major adverse cardiovascular events rates and decreased bleeding events without an increase in stent thrombosis compared with those taking triple therapy.¹² It should be noted that approximately 1/3 of patients in the trial underwent BMS implantation. BMS should continue to play an important role in those taking oral anticoagulants who are at higher risk for bleeding.

Conclusion

Morice and colleagues collected data from 31 centers in Europe and Asia to identify the main reason for implantation of BMS rather than DES in 744 consecutive PCIs.¹³ Eight indications for using BMS were identified (Table 1).

Reason for BMS Use	Number	Percentage
Large vessel diameter	241	32.4%
ST-segment elevation MI	132	17.7%
Advanced age	92	12.4%
Concomitant oral anticoagulant treatment	84	11.3%
Increased bleeding risk, cancer, or anemia	71	9.5%
Reimbursement/regulatory/other reasons	70	9.4%
Planned noncardiac surgery within the next year	41	5.5%
Anticipated poor DAPT compliance	13	1.7%

As stent technology continues to improve and antiplatelet regimens become more tailored, BMS will still serve an important role in PCI.

References

1. Steinberg DH, Mishra S, Javaid A, et al. Comparison of effectiveness of bare metal stents versus drug-eluting stents in large (> or =3.5 mm) coronary arteries. Am J Cardiol 2007;99:599-602.
2. Brunner-La Rocca HP, Kaiser C, Pfisterer M; BASKET Investigators. Targeted stent use in clinical practice based on evidence from the Basel Stent Cost Effectiveness Trial (BASKET). Eur Heart J 2007;28:719-25.
3. Pfisterer M, Brunner-La Rocca HP, Rickenbacher P, et al. Long-term benefit-risk balance of drug-eluting vs. bare-metal stents in daily practice: does stent diameter matter? Three-year follow-up of BASKET. Eur Heart J 2009;30:16-24.
4. Kaiser C, Galatius S, Erne P, et al. Drug-eluting versus bare-metal stents in large coronary arteries. N Engl J Med 2010;363:2310-9.
5. Singla S, Sachdeva R, Uretsky BF. The risk of adverse cardiac and bleeding events following noncardiac surgery relative to antiplatelet therapy in patients with prior percutaneous coronary intervention. J Am Coll Cardiol 2012;60:2005-16.
6. Spertus JA, Kettelkamp R, Vance C, et al. Prevalence, predictors, and outcomes of premature discontinuation of thienopyridine therapy after drug-eluting stent placement: results from the PREMIER registry. Circulation 2006;113:2803-9.
7. Levine GN, Bates ER, Blankenship JC, et al. 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention. A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. J Am Coll Cardiol 2011;58:e44-122.
8. Levine GN, Bates ER, Bittl JA, et al. 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2016;68:1082-115.
9. Schafer PE, Sacrinty MT, Cohen DJ, et al. Cost-effectiveness of drug-eluting stents versus bare metal stents in clinical practice. Circ Cardiovasc Qual Outcomes 2011;4:408-15.
10. de Belder A, de la Torre Hernandez JM, Lopez-Palop R, et al. A prospective randomized trial of everolimus-eluting stents versus bare-metal stents in octogenarians: the XIMA Trial (Xience or Vision Stents for the Management of Angina in the Elderly). J Am Coll Cardiol 2014;63:1371-5.
11. Roffi M, Patrono C, Collet JP, et al. 2015 ESC Guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation: Task Force for the Management of Acute Coronary Syndromes in Patients Presenting without Persistent ST-Segment Elevation of the European Society of Cardiology (ESC). Eur Heart J 2016;37:267-315.
12. Dewilde WJ, Oirbans T, Verheugt FW, et al. Use of clopidogrel with or without aspirin in patients taking oral anticoagulant therapy and undergoing percutaneous coronary intervention: an open-label, randomised, controlled trial. Lancet 2013;381:1107-15.
13. Morice MC, Urban P, Greene S, Schuler G, Chevalier B. Why are we still using coronary bare-metal stents? J Am Coll Cardiol 2013;61:1122-3.

Keywords: Acute Coronary Syndrome, Anemia, Angina, Stable, Angiography, Angioplasty, Balloon, Coronary, Anticoagulants, Atrial Fibrillation, Diabetes Mellitus, Drug-Eluting Stents, Myocardial Infarction, Neoplasms, Percutaneous Coronary Intervention, Pulmonary Embolism, Risk Factors, Stroke, Thrombosis, Ticlopidine, Warfarin

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