The US should follow Europe’s lead and change guidelines on embolic protection in saphenous vein grafting

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Timir Paul

The revised European Society of Cardiology (ESC) myocardial revascularisation guidelines have downgraded the use of embolic protection devices during saphenous vein graft intervention from Class I (should be used) to Class IIa (reasonable to use).1 The change in recommendation is based on a meta-analysis that indicated that embolic protection during percutaneous coronary intervention (PCI) in a saphenous vein graft does not provide benefit in the contemporary interventional era.2 Timir K Paul, the lead author of the meta-analysis, argues that the US societies should also change their recommendations on using embolic protection devices during saphenous vein graft intervention.

As well as showing that the use of embolic protection during PCI in saphenous vein grafts does not provide benefit, our meta-analysis also showed that it may even increase the risk of periprocedural myocardial infarction. On the basis of this, in an interview with this newspaper, I suggested that current guideline recommendations should be reassessed and possibly consider downgrading embolic protection use in this context to Class II.3

The 2011 ACC/AHA and older ESC guidelines give the use of embolic protection device a Class I indication for saphenous vein graft intervention when technically feasible.4 The guideline recommendations are based on only one randomised controlled trial that was published in 2002 and that only have 30-day outcomes data.5 However, subsequent to the publication of the US guidelines, several studies in this regard have shown conflicting results. A large National Cardiovascular Data Registry CathPCI Registry showed no benefits in routine use of an embolic protection device during saphenous vein grafts intervention and noted a higher incidence of periprocedural complications in the embolic protection group.6 Moreover, in the recent era, no-reflow and periprocedural myocardial infarction during saphenous vein grafts intervention has decreased—probably because of the use of more potent pharmacotherapy, pretreatment with dual antiplatelet therapy (DAPT), and less bulky and highly deliverable balloons and stents. Thus, the routine use of embolic protection devices in saphenous vein grafts intervention has been questioned in the contemporary PCI era.

Reviewing results from eight studies, in our meta-analysis, my colleagues and I identified 52,893 patients who had undergone saphenous vein grafts intervention—of whom, 11,506 had undergone intervention with an embolic protection device and 41,387 had undergone intervention without protection. There were no significant differences between the groups in the rate of all-cause mortality, major adverse cardiovascular events, target vessel revascularisation, late myocardial infarction, or periprocedural myocardial infarction. Surprisingly, when a fixed-effect model was used, contrary to the expected benefit of the use of embolic protection device, it was associated with 1.5-fold higher periprocedural myocardial infarction (p<0.0001) compared with no embolic protection devices. This result questions the necessity of routine use of embolic protection devices during saphenous vein grafts intervention as the main goal of embolic protection devices is to reduce no reflow and prevent periprocedural myocardial infarction. Therefore, in the conclusion of our meta-analysis, we recommended that randomised controlled trials are needed in the current era to evaluate long-term outcomes with routine use of embolic protection device and, in the meantime, current guideline recommendations on embolic protection device use should be revisited.

Despite the Class I recommendation for embolic protection, we found the use of embolic protection devices in saphenous vein grafts intervention to be low (21.7%). Regardless of embolic protection device use, the periprocedural events rate remained approximately 10% across the studies—indicating that embolic protection use was not always successful. The use of embolic protection device increases the procedure time and complexity and cannot be used in all saphenous vein grafts due to size, anatomic location, and lesion complexity. Even if a embolic protection device is used, it may not completely seal the distal vessel and may be unsuccessful in preventing distal embolisation. Additionally, embolic protection use is associated with procedural complications including vessel perforation, dissection and device entrapment. Simpler techniques, such as direct stenting, under-sizing stents with higher stent/lesion length ratio and periprocedural vasodilator therapy, have proven beneficial in preventing no reflow phenomenon without using embolic protection devices.

With this current change in the ESC guidelines, physicians do not have to use embolic protection in saphenous vein graft intervention if they feel it would not be beneficial. However, they still have the option of using it at their discretion. Current ACC/AHA mandate the use of embolic protection device in saphenous vein graft interventions with a Class I recommendation, which I feel should be revised; particularly, as the recommendation in based on only one randomised trial that was published 16 years ago and may not be applicable in this current clinical practice.

There are many clinical scenarios in cardiology practice in which guideline recommendations are Class IIa. The new ESC guideline will not completely prevent the use of embolic protection device as they may still be used in selected higher risk patients. But, the revised recommendations will lead to less use of embolic protection devices, which will reduce significant healthcare costs by reducing procedural time, contrast agent, radiation and decreasing procedural related complications (as well as reducing device costs because fewer devices will be used). Potentially, they will also protect physicians from unnecessary litigations.

There will probably be substantial criticisms about the new ESC recommendations from operators who routinely use embolic protection devices in saphenous vein grafts intervention and who strongly feel that they are useful devices. Such operators are likely to oppose any similar update to the US guidelines. After all, changing your practice pattern can be hard due to “habitual reflex”. But, I hope eventually the experts from USA will review the first trial in depth and reassess the guidelines in a similar way that the experts in Europe have.

References:

  1. 2018 ESC/EACTS Guidelines on myocardial revascularization. European Heart Journal (2018) 00: 1–96
  2. Paul et al. Circ Cardiovasc Interv 2017. Epub.
  3. BIBA Medical Staff. Cardiovascular News 2018. https://bit.ly/2zB5mux (date accessed 28 September 2018).
  4. Levine et al. Circulation 2011; 124: e574–e651.
  5. Baim et al. Circulation 2002; 105: 1285–90.
  6. Brennan et al. Circulation: Cardiovascular Interventions 2015; 8: e001403.

Timir K Paul is at the Division of Cardiology, Department of Internal Medicine, East Tennessee State University, Johnson City, USA.

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