Guidelines and Appropriateness Criteria for Interventional Cardiology

Guideline Development

The ACCF and AHA have adopted a strict and rigorous process for guideline development. The joint guideline committee identifies topics of interest and selects a writing committee composed of recognized experts in the field, seasoned clinicians, generalists, and other health care providers from associated disciplines, including nurses and pharmacists. Recent recommendations are to also include a patient advocate. The evidence from clinical registries and trials is collated, rigorously reviewed, and analyzed to assist the committee in formulating its recommendations. These recommendations are categorized into four classes: Class I is defined as procedures or treatment that SHOULD be performed or administered; Class II indications are those where it is REASONABLE to do the procedure/treatment (IIa) or where it MAY BE CONSIDERED (IIb); and Class III is defined as one that is anticipated to have NO BENEFIT or the procedure or treatment would cause HARM. The level of evidence for each recommendation is an important component of the process. Level A is used when the recommendation is supported by either multiple randomized trials or a metaanalysis; Level B is used when the recommendation is supported by either a single randomized trial or nonrandomized studies; and Level C is used when the recommendation is supported by either limited evidence, the consensus opinion of experts, or the standard of care. The final guidelines document is peer reviewed by external experts and revised before the final document is approved by the participating organizations. The process is lengthy, which limits the ability to quickly revise the guidelines as new information from clinical trials alters practice. Efforts to improve the process and increase the speed and rigor of guideline development have been described. While clinical trial data are critical to the formulation of guidelines, the lack of trials in many areas of practice unfortunately has resulted in Level C evidence (expert opinion), responsible for 48% of all guideline recommendations.

For the purposes of this chapter, only current ACCF/AHA guidelines are reviewed and only key recommendations that are directly pertinent to interventional cardiology practice are discussed. Please refer the original documents for a more detailed discussion of the guidelines and the evidence supporting the recommendations.

Guidelines for ST-Elevation Myocardial Infarction

The 2013 STEMI guidelines build upon the recommendations of the prior documents. This and past documents should be referred to for a more in-depth discussion of the recommendations and the evidence supporting them.

The guidelines recommend that the initial management of patients with an acute ST-segment myocardial infarction (STEMI) is the rapid reperfusion of the infarct artery. A reduction in the duration of the coronary occlusion results in a reduction in infarct size and mortality. Of the two reperfusion strategies, fibrinolysis or angioplasty, PCI is the preferred strategy when it can be performed expeditiously. The guidelines recommend that it should be accomplished within a time frame, from the first medical contact (FMC) to the first device, of less than 90 minutes and preferably within 60 minutes in patients who present within 12 hours of the onset of symptoms (Class IA) ( Figure 2-2 ). To achieve this goal, it is recommended that all communities create and maintain a regional system of care with integrated emergency medical services (EMS) and hospital systems that meet the guidelines for rapid diagnosis and triage (Class IB). Patients should be transferred by emergency medical systems (EMS) to PCI-capable hospitals for primary PCI. When patients present at a non-PCI-capable hospital, immediate transfer to a PCI-capable hospital should be done as rapidly as possible, with a goal of 120 minutes from the FMC to device use (Class Ib) and a door-in to door-out time at the first hospital of 30 minutes or less. When the FMC to device time is anticipated to be more than 120 minutes, a fibrinolytic agent should be given first, unless contraindicated. It is reasonable to then transfer the patient for PCI within 3 to 24 hours (the so-called pharmaco-invasive strategy) (Class IIa-b). When this strategy is chosen, the fibrinolytic agent should be administered within 30 minutes of hospital arrival. The guideline class (COR) and level of evidence (LOE) for these primary PCI strategies are shown in Figures 2-2, 2-3, 2-4, and 2-5 .

The management of patients with cardiogenic shock or severe heart failure is more aggressive with recommendations for PCI, regardless of the time after the onset of the symptoms or first contact. In this setting urgent transfer to a PCI-capable hospital is critical. Transfer for a failure of fibrinolytic therapy is also a reasonable strategy (so-called rescue angioplasty) (Class IIa-b). The guidelines for coronary angiography and potential PCI when a fibrinolytic agent is given or the patient received no reperfusion is shown in Figure 2-4 .

The national efforts to improve ischemic time (symptom onset to device/drug) have focused on the FMC to device time and particularly a key component of this time—the door to device time (D2D). Public reporting and efforts such as the AHA Mission Lifeline program and the ACCF D2B program have been successful in improving D2D times. The strategies to achieve this reduction have included prehospital ECG and activation of the cath lab while en route to the hospital, ED activation of the PCI team, a single page for activation of the cath lab, <20 minutes until cath lab staff arrive, and timely feedback to the STEMI care team. While these measures have been effective, the greatest delay in reperfusion is often the delay between the onset of symptoms to the 911 call or the hospital arrival. There are many reasons for this delay, and unfortunately, national efforts to reduce this time have not been successful.

Once the patient arrives at the cath lab, the interventional procedure should be performed expeditiously. Antiplatelet and anticoagulant therapy should be given as soon as possible upon initial medical contact. Dual antiplatelet therapy (aspirin and clopidogrel or prasugrel or ticagrelor) and an anticoagulant (UFH or bivalirudin) should be administered. GP IIb/IIIa agents (abciximab, tirofiban, or eptifibatide) are reasonable in combination with UFH (Class IIa). In current practice, the use of GP IIb/IIa agents has decreased due to concerns about increased bleeding risk, the introduction of the newer more potent P ₂ Y ₁₂ antiplatelet agents, and the greater use of bivalirudin. Based on randomized trials, the guideline committee felt it was not unreasonable to perform an aspiration thrombectomy (Class IIa-b). Recent trials have been mixed, and many operators have restricted the use to those situations where there is a large clot burden. Drug eluting stents (DES) or bare metal stents (BMS) should be used when possible (Class Ia). Most operators have favored DES, given evidence from large randomized trials of improved long-term outcomes, particularly the reduction in target vessel revascularization without an increased risk of stent thrombosis. BMS should be used when there is an increased risk of bleeding or a concern about compliance with dual antiplatelet therapy for 1 year (Class IC). Initial primary PCI should be restricted to the infarct-related artery, and current guidelines recommend against treatment of other significant stenosis at the same setting. Multivessel PCI is indicated in patients who develop spontaneous symptoms of ischemia (Class Ic) and those patients with an intermediate to high risk of noninvasive testing prior to discharge (Class IIa). These recommendations have been recently challenged following the results of the PRAMI trial that demonstrate improved outcomes with multivessel PCI at the same setting as the primary PCI. A number of large randomized trials are ongoing to help address this issue.

Coronary artery bypass surgery is indicated for patients not amenable to PCI and those who have ongoing or recurrent ischemia, cardiogenic shock, severe heart failure, or other high-risk features (Class Ib). CABG is rarely used as the primary reperfusion strategy, but it is commonly used for other indications during hospitalization, particularly in patients who have extensive coronary disease or have disease that is not amenable to PCI.

The subsequent medical management with dual antiplatelet therapy, oral anticoagulants, beta-blockers, ACE or ARB agents, and statins, in addition to risk factor modification and cardiac rehabilitation, are critically important in improving long-term outcomes and preventing future events. The reader should refer to the STEMI guidelines for specific recommendations.