Timir K. Paul, MD, PhD, FSCAI; Huu Tam Truong, MD, FSCAI; and Faisal Latif, MD, FSCAI

Introduction

Percutaneous coronary intervention (PCI) of saphenous vein grafts (SVGs) poses a higher risk of distal embolization and no-reflow with attendant periprocedural myocardial infarction and in-hospital and long-term mortality.¹ In this Tip of the Month, we will discuss strategies to optimize outcomes of SVG PCI.

Guide Selection

During SVG PCI, aggressive backup support is typically not necessary unless the lesion is very distal or delivery of an embolic protection device (EPD) is anticipated to be challenging, such as a graft with an upward trajectory. From a transfemoral approach, Judkins Right (JR4), Amplatz Left (AL)1, left coronary bypass, or Hockey Stick guides for left-sided grafts and JR4 or multipurpose (MP) guides for right-sided grafts generally provide requisite support. From a right transradial approach, AL guides work well for left-sided grafts, but engagement of right-sided grafts can be challenging. From a left transradial approach, AL and MP guides work well. When guides are unable to engage the SVG ostium adequately, guide extension to opacify the graft and deliver stents can be very useful.² Shorter guides should be used when performing PCI on very distal lesions or distal to a sequential graft to ensure the balloon shaft is long enough to deliver the balloon/stent to target.

General Considerations in SVG PCI

1. Give preference to PCI of the native coronary if feasible, particularly if the SVG graft is degenerated.³
2. Avoid balloon predilatation unless the lesion is severely stenotic or if required for the delivery of an EPD.⁴
3. Consider EPD whenever technically feasible.
4. Utilize microvascular vasodilators liberally, even before balloon angioplasty/stenting.
5. Avoid post-dilatation.
6. If post-dilatation is performed, size the balloon 1:1 with the graft.
7. Perform slow and prolonged stent and balloon inflation at nominal pressures.
8. Consider slightly undersized stent but a longer stent length to reduce plaque extrusion through stent struts.⁵
9. Consider thrombectomy in lesions with a heavy thrombus burden.
10. Keep activated clotting time on the higher side.
11. Consider prolonged dual anti-platelet therapy (DAPT) based on the DAPT score,⁶ as SVG PCI is considered high-risk for ischemic events.

Minimizing Distal Embolization and/or No-Reflow

Distal EPD

If the risk of embolization is high, an EPD should be used when technically feasible (Class IB), as per the 2011 American College of Cardiology (ACC)/American Heart Association (AHA) guidelines.⁷ A meta-analysis including 52,893 patients suggested that the routine use of an EPD during SVG intervention is not associated with a reduction in all-cause mortality or cardiovascular events.⁸ The 2018 European Society of Cardiology (ESC) Guidelines on Myocardial Revascularization give a class IIa recommendation for the use of an EPD in SVG intervention.³

Options When EPD Is Not Available

Aspiration of the stagnant blood column in the SVG created by inflation of a distal balloon with an aspiration catheter or the guide itself has been described to prevent no-reflow.^{9, 10} This concept is similar to that used in distal balloon occlusion EPDs, which are no longer commercially available.

Treatment of No-Reflow With or Without EPD

When no-reflow occurs while using an EPD, the filter may be filled with embolized atheromatous/thrombotic materials. In this situation, it is very important to perform an aspiration thrombectomy of the graft prior to retrieval of the filter. Regardless of whether an EPD is used, intracoronary microvascular vasodilators, including verapamil, adenosine, nitroprusside, or nicardipine, are highly effective in both the prevention and treatment of no-reflow.¹¹ It is more effective to administer these drugs using a microcatheter, infusion catheter, or an over-the-wire balloon placed distally.

Treatment of Heavy Thrombus Burden

In the presence of a large thrombus burden in SVGs, the following strategies can be employed (with or without EPD), although their clinical benefits have not been well demonstrated in large clinical trials.

1. Mechanical thrombectomy with either the AngioJet thrombectomy system (Boston Scientific) or CAT RX catheter (Penumbra’s Indigo^® System) for the removal of a large thrombus
2. Aspiration thrombectomy with dedicated aspiration catheters, such as Pronto (Teleflex) or Export™ (Medtronic), or guide extensions such as GuideLiner^® (Teleflex) or Guidezilla™ (Boston Scientific)
3. Laser atherectomy
4. Anecdotally, bailout use of intragraft fibrinolytics such as tPA

Stent Choice

As per the current evidence, bare-metal and drug-eluting stents are equally effective and safe in SVG intervention.¹² The choice of stents would be individualized based on the lesion type, diameter, long-term DAPT tolerance, and patient’s adherence to medications.

Conclusion

SVG interventions can present unique challenges for interventional cardiologists. Some of the above strategies can be applied to minimize complications and optimize outcomes.

References

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9. Morales PA, Heuser RR. Guiding catheter aspiration to prevent embolic events during saphenous vein graft intervention. J Interv Cardiol. 2002 Dec;15(6):491–497.
10. Stein BC, Moses J, Teirstein PS. Balloon occlusion and transluminal aspiration of saphenous vein grafts to prevent distal embolization. Catheter Cardiovasc Interv. 2000;Sep;51(1):69–73.
11. Fischell TA, Subraya RG, Ashraf K, et al. “Pharmacologic” distal protection using prophylactic, intragraft nicardipine to prevent no-reflow and non-Q-wave myocardial infarction during elective saphenous vein graft intervention. J Invasive Cardiol. 2007 Feb;19(2):58–62.
12. Brilakis ES, Edson R, Bhatt DL, et al. Drug-eluting stents versus bare-metal stents in saphenous vein grafts: a double-blind, randomised trial. Lancet. 2018 May 19;391(10134):1997–2007.