By: Suresh Mulukutla, MD, FSCAI, and Jayant Bagai, MD, FSCAI

Introduction 

As interventional cardiologists, one of the most important conditions we treat is ST-elevation myocardial infarction (STEMI). Several issues must be considered in the care of these patients. The focus should be on the performance of an expeditious, safe, and successful procedure with the primary objective of achieving Thrombolysis in Myocardial Infarction (TIMI) flow 3 and adequate perfusion of the myocardial tissue bed in a timely manner (door-to-balloon time less than 90 minutes) while trying to prevent access site bleeding, slow/no reflow and distal embolization of thrombus. In this SCAI Tip of the Month, we highlight some of the considerations in primary percutaneous coronary intervention (PCI), based on contemporary data and published guidelines.

Single-Guide Strategy When using transradial access for primary PCI, a single, “universal” guiding catheter to perform both left and right coronary angiography and PCI—such as an Ikari-Left 1.5 or MAC 3.5 guide—can be considered to reduce door-to-balloon time and overall ischemic time.1 Such a strategy is feasible but should be used in STEMI only when the operator is comfortable with this approach.
Multivessel PCI Options

In certain scenarios, immediate multivessel PCI (MVPCI) may be required due to the presence of more than one culprit artery, an unclear culprit artery, or ongoing chest pain with reduced flow in a severely stenotic non-infarct-related coronary artery.

More recent data from randomized controlled trials (RCTs) have shown significant reductions in myocardial infarction (MI), death or MI, and ischemia-driven revascularization in patients undergoing immediate MVPCI compared with culprit-only PCI.2, 3 Importantly, patients with left main stenosis > 50%, chronic total occlusion, renal insufficiency, and cardiogenic shock were excluded in these RCTs. These findings are also supported by meta-analysis.4, 5 Based on the data, the prior Class III (Harm) recommendation with regard to MVPCI in hemodynamically stable patients with STEMI has been upgraded and modified to a Class IIb recommendation to include consideration of MVPCI, either at the time of primary PCI or as a planned, staged procedure, in the 2015 American College of Cardiology (ACC)/American Heart Association (AHA)/SCAI-focused update on primary PCI for STEMI.6

Ultimately, clinical judgment should be used before proceeding with immediate MVPCI based on the patient’s clinical situation and comorbidities such as renal insufficiency, lesion complexity, and the risk of the procedure.

It is unclear if the benefit of complete revascularization in patients with STEMI is restricted to immediate MVPCI or is also evident in patients undergoing so-called “staged” PCI, either as an inpatient or within six weeks of the index event. A strategy of fractional flow reserve (FFR)-guided nonculprit MVPCI, either at the time of primary PCI or later in the hospital stay, has been shown to be safe and beneficial in reducing all-cause death, MI, and revascularization.7, 8 Ongoing RCTs such as COMPLETE and FULL REVASC will help to answer some of these questions.

Based on the results of the CULPRIT-SHOCK trial, coronary revascularization should be focused on the culprit vessel in the setting of cardiogenic shock.9

Antiplatelet Strategies

Dual antiplatelet therapy (DAPT) loading and maintenance are critical for primary PCI. The 2013 ACC/AHA STEMI guidelines provide a Class I recommendation for clopidogrel, prasugrel, and ticagrelor loading and maintenance. Based on RCT data, prasugrel was associated with a lower rate of nonfatal MI and stent thrombosis and ticagrelor with lower cardiac mortality and MI compared with clopidogrel, when given to patients with acute coronary syndrome (ACS), including STEMI. Prasugrel was associated with greater major bleeding compared with clopidogrel, whereas ticagrelor was not. The recently reported ISAR-REACT 5 study showed a lower incidence of death, MI, and stroke with prasugrel compared with ticagrelor in patients with ACS, of which 41% had STEMI. There were significant reductions in death, as well as MI, with no difference in major bleeding, stent thrombosis, or stroke.10 Prasugrel should not be used in patients with a history of stroke or transient ischemic attack (TIA).

Peri-PCI intravenous cangrelor was compared with a loading dose of clopidogrel pre-PCI in the CHAMPION-PHOENIX trial, which included more than 2,000 patients with STEMI (~ 18% of the total study population).11 The composite endpoint of all-cause death, MI, ischemia-driven revascularization, or stent thrombosis at 48 hours was significantly lower in the cangrelor group than in the clopidogrel group and was not associated with an increased risk of major bleeding or transfusion. Cangrelor can, therefore, be considered in patients who need rapid platelet inhibition and especially patients in whom drug absorption is expected to be significantly delayed, such as patients with cardiogenic shock or emesis. Cangrelor offers the benefit of potent platelet inhibition with a rapid offset of action (given its very short half-life of three-to-five minutes) and a lower risk of major bleeding, compared with glycoprotein IIb/IIIa inhibitors (GPI).

Radial Access Transradial PCI was associated with significant reductions in death and major bleeding, compared with transfemoral PCI, in prior RCTs—though no difference was noted in a recent RCT.12 Therefore, while radial access for primary PCI in STEMI is safe and validated, operators and catheterization laboratories should remain comfortable and facile with both radial and femoral approaches so that either option can be used safely.
Thrombectomy Role Routine aspiration thrombectomy before primary PCI is not recommended (Class III: No Benefit, level of evidence A). There are insufficient data to assess the potential benefit of a strategy of selective or bailout aspiration thrombectomy (Class IIb, level of evidence C-LD).6 Ongoing trials with newer devices for management of large thrombus (TIMI thrombus grade 4 or 5) are ongoing. In the meantime, clinical judgment for the use of adjunctive therapies, such as GPI and aspiration thrombectomy, should be used for management of large thrombus.

 

Conclusion

Primary PCI for STEMI is a lifesaving procedure, and it is important to be aware of evidence-based data on drug, device, and technical considerations for primary PCI. Meticulous arterial access and PCI technique, combined with judicious use of antiplatelet therapies, clinical judgment, and evidence-based guidelines, for the management of large thrombus and multivessel coronary artery disease during primary PCI are of vital importance.

 

References 

  1. Guo J, Chen W, Wang G, Liu Z, et al. Safety and Efficacy of Using a Single Transradial MAC Guiding Catheter for Coronary Angiography and Intervention in Patients with ST Elevation Myocardial Infarction. J Interv Cardiol. 2017 Feb; 30(1):33-42.
  2. Wald DS, Morris JK, Wald NJ, et al. Randomized trial of preventive angioplasty in myocardial infarction. N Engl J Med. 2013 Sep 19; 369(12):1115-23.
  3. Gershlick AH, Khan JN, Kelly DJ, et al. Randomized trial of complete versus lesion-only revascularization in patients undergoing primary percutaneous coronary intervention for STEMI and multivessel disease: the CvLPRIT trial. J Am Coll Cardiol. 2015 Mar 17; 65(10):963–72.
  4. El-Hayek GE, Gershlick AH, Hong MK, Dominguez A, Banning A, Afshar AE, Herzog E, Tamis-Holland JE. Meta-Analysis of Randomized Controlled Trials Comparing Multivessel Versus Culprit-Only Revascularization for Patients With ST-Segment Elevation Myocardial Infarction and Multivessel Disease Undergoing Primary Percutaneous Coronary Intervention. Am J Cardiol. 2015 Jun 1; 115(11):1481-6.
  5. Bangalore S, Toklu B, Stone GW. Meta-Analysis of Culprit-Only Versus Multivessel Percutaneous Coronary Intervention in Patients With ST-Segment Elevation Myocardial Infarction and Multivessel Coronary Disease. Am J Cardiol. 2018 Mar 1; 121(5):529-536.
  6. Levine GN, Bates ER, Blankenship JC, et al. 2015 ACC/AHA/SCAI Focused Update on Primary Percutaneous Coronary Intervention for Patients With ST-Elevation Myocardial Infarction: : An Update of the 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention and the 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction. J Am Coll Cardiol. 2016 Mar 15; 67(10):1235-1250.
  7. Engstrom T, Kelbaek H, Helqvist S, et al. Complete revascularisation versus treatment of the culprit lesion only in patients with ST-segment elevation myocardial infarction and multivessel disease (DANAMI-3-PRIMULTI): an open-label, randomised controlled trial. Lancet. 2015 Aug 15; 386(9994):665–71.
  8. Smits PC, Abdel-Wahab M, Neumann FJ, et al. Fractional Flow Reserve-Guided Multivessel Angioplasty in Myocardial Infarction. N Engl J Med. 2017 Mar 30; 376(13):1234-1244.
  9. Thiele H, Akin I, Sandri M, et al. PCI Strategies in Patients with Acute Myocardial Infarction and Cardiogenic Shock. N Engl J Med. 2017 Dec 21; 377(25):2419-2432.
  10. Schüpke S, Neumann FJ, Menichelli M, et al. Ticagrelor or Prasugrel in Patients with Acute Coronary Syndromes. N Engl J Med. 2019 Oct 17; 381(16):1524-1534.
  11. Bhatt DL, Stone GW, Mahaffey KW, et al. Effect of platelet inhibition with cangrelor during PCI on ischemic events. N Engl J Med. 2013 Apr 4; 368(14):1303-13.
  12. Safety and Efficacy of Femoral Access vs RadIal Access in STEMI - SAFARI-STEMI, presented at the 2019 ACC Scientific Sessions.

 

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