Facilitated PCI might be performed as a reperfusion strategy in higher-risk patients when PCI is not imme-
diately available and bleeding risk is low. (Level of
Evidence: B)
Facilitated PCI refers to a strategy of planned immediate PCI after an initial pharmacological regimen such as full- dose fibrinolysis, half-dose fibrinolysis, a GP IIb/IIIa inhibitor, or a combination of reduced-dose fibrinolytic ther- apy and a platelet GP IIb/IIIa inhibitor. Facilitated PCI should be differentiated from primary PCI without fibrinoly- sis or GP IIb/IIIa inhibitor therapy, from primary PCI with a GP IIb/IIIa inhibitor started at the time of PCI, and from res- cue PCI after unsuccessful fibrinolysis. Potential advantages include earlier time to reperfusion, improved patient stabili- ty, greater procedural success rates, higher TIMI flow rates, and improved survival rates (36,346,428,469,470). However, ond hospital should be as short as possible, with a goal of
within 90 minutes. Significant reductions in door-to-balloon times might be achieved by directly transporting patients to PCI centers rather than transporting them to the nearest hos- pital, if interhospital transfer will subsequently be required to obtain primary PCI.
6.3.1.6.4.3. Primary Stenting
Of the 22 randomized trials that compared primary PCI with fibrinolytic therapy, 12 involved a comparison of primary PCI with stenting and fibrinolytic therapy (40,173,177,306,307,408,409,414,417-421). These investi- gations demonstrate that PCI-treated patients experience lower mortality rates (5.9% versus 7.7%, OR 0.75, 95% CI 0.60 to 0.94, p equals 0.013), less reinfarction (1.6% versus 5.1%, OR 0.31, 95% CI 0.21 to 0.44, p equals 0.0001), and less hemorrhagic stroke than those treated by fibrinolysis (40). Compared with PTCA, intracoronary stents achieve a better immediate angiographic result with a larger arterial lumen, less reocclusion and restenosis of the infarct-related artery, and fewer subsequent ischemic events.
Primary stenting has been compared with primary angio- plasty in 9 studies (38,37,460-467). There were no differ- ences in mortality (3.0% versus 2.8%) or reinfarction (1.8% versus 2.1%) rates. However, major adverse cardiac events were reduced, driven by the reduction in subsequent target- vessel revascularization with stenting (Figure 25) (37).
Figure 25.Primary stenting versus primary angioplasty. Odds Ratios and their 95% confidence intervals for primary stenting versus primary angioplasty for the risk of death, reinfarction, target vessel revascularization (TVR), and major adverse cardiac events (MACE) over a 6- to 12-month follow-up after ST-elevation myocardial infarction (STEMI). The meta-analysis was performed without (subtotal) and with (total) the abciximab arms of the CADILLAC trial. Modified from Zhu M et al. Am J Cardiol 2001;88:299. Copyright 2001, with permission from Excerpta Medica, Inc. (37).
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ischemia. Rescue PCI has resulted in higher rates of early infarct artery patency, improved regional infarct-zone wall motion, and greater freedom from adverse in-hospital events than with a deferred PCI strategy or medical therapy. The Randomized Evaluation of Rescue PCI with Combined Utilization End Points (RESCUE) trial demonstrated a reduction in rates of in-hospital death and a combined end point of death and CHF that was maintained up to 1 year after study entry for patients presenting with anterior STEMI who failed fibrinolytic therapy, when PCI was performed within 8 hours after the onset of symptoms (477). Improvement in TIMI grade flow from less than or equal to 2 to 3 may offer additional clinical benefit. Similar data are not available for patients with nonanterior STEMI.
A major problem in adopting a strategy of rescue PCI lies in the limitation of accurate identification of patients for whom fibrinolytic therapy has not restored antegrade coro- nary flow. Unless unsuccessful fibrinolysis is recognized and corrected quickly (within 3 to 6 hours of onset of symptoms), salvage of ischemic myocardium is unlikely. Unfortunately, clinical markers of reperfusion, such as relief of ischemic- type chest discomfort, partial resolution of ST-segment ele- vation, and reperfusion arrhythmias, have limited predictive value in identifying failure of fibrinolysis (478). In a prior era in which the practice of PCI was less mature, immediate catheterization of all patients after fibrinolytic therapy to identify those with an occluded infarct artery was found to be impractical, costly, and often associated with bleeding com- plications (479,480). This strategy is being re-evaluated in clinical trials testing facilitated PCI in the contemporary PCI setting.
Even in the patient with documented failure of fibrinolysis, rescue PCI has limitations. Because extensive myocardial necrosis occurs when coronary occlusion has been present for more than 3 hours (18), PCI may not salvage a substan- tial amount of myocardium, considering the time delay asso- ciated with presentation of the patient to the hospital after onset of symptoms, infusion of the fibrinolytic agent, recog- nition of failed fibrinolysis, and subsequent initiation of PCI. Rescue PCI fails to reestablish antegrade coronary flow in approximately 10% of patients, and reocclusion of the infarct artery occurs in as many as 20% of the remainder (481), although use of GP IIb/IIIa inhibitors and stent implantation may improve these results. Unsuccessful rescue PCI is asso- ciated with a high mortality rate (482,483). Finally, coronary reperfusion occurs over the subsequent hours after fibri- nolytic therapy in many patients. Although infarct artery patency is achieved in only 50% to 85% of patients 90 min- utes after fibrinolytic therapy, it rises to 90% by 24 hours (474). Such late reperfusion may improve survival without the risk of invasive procedures coupled with fibrinolytic therapy. Confounding the issue, both fibrinolytic therapy and PCI may successfully restore flow in the epicardial artery but fail to improve microvascular perfusion.
Hours to days after failed fibrinolysis. Patency of the infarct- related artery is an important predictor of mortality in sur- preliminary studies have not demonstrated any benefit in
reducing infarct size or improving outcomes (471-473). It is unlikely that this strategy would be beneficial in low-risk patients.
A strategy of facilitated PCI holds promise in higher-risk patients when PCI is not immediately available. Potential risks include increased bleeding complications, especially in those 75 years of age or older (see Section 6.3.1.6.3.8), and potential limitations include added cost. Several randomized trials of facilitated PCI with a variety of pharmacological regimens are in progress (473a).
6.3.1.6.4.5. Rescue PCI
Class I1. Rescue PCI should be performed in patients less than 75 years old with ST elevation or LBBB who develop shock within 36 hours of MI and are suitable for revascularization that can be performed within 18 hours of shock unless further support is futile because of the patient’s wishes or contraindications/unsuit-
ability for further invasive care. (Level of Evidence: B)
2. Rescue PCI should be performed in patients with severe CHF and/or pulmonary edema (Killip class 3)
and onset of symptoms within 12 hours. (Level of
Evidence: B)
Class IIa
1. Rescue PCI is reasonable for selected patients 75 years or older with ST elevation or LBBB or who develop shock within 36 hours of MI and who are suitable for revascularization that can be performed within 18 hours of shock. Patients with good prior functional status who are suitable for revasculariza- tion and who agree to invasive care may be selected
for such an invasive strategy.(Level of Evidence: B)
2. It is reasonable to perform rescue PCI for patients with 1 or more of the following:
a. Hemodynamic or electrical instability (Level of
Evidence: C)
b. Persistent ischemic symptoms. (Level of Evidence:
C)
Immediately after failed fibrinolysis.Intravenous fibrinolytic therapy successfully restores coronary TIMI 2/3 flow at 90 minutes in 50% to 85% of patients with STEMI (474). In those in whom fibrinolysis is unsuccessful, antegrade coro- nary flow can usually be restored with PCI. Several studies have demonstrated the marked beneficial effect of infarct- related artery patency (obtained via endogenous, pharmaco- logical, or mechanical recanalization) on survival in patients with STEMI (475,476). Survivors of STEMI with a patent infarct-related artery demonstrated at 90 minutes after treat- ment have an improved long-term outcome compared with those with an occluded infarct-related artery, even when LV systolic function is similar (476). Rescue (also known as sal- vage) PCI is defined as PCI within 12 hours after failed fib- rinolysis for patients with continuing or recurrent myocardial
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shock within 36 hours of MI and are suitable for revascularization that can be performed within 18 hours of shock unless further support is futile because of the patient’s wishes or contraindications/unsuit-
ability for further invasive care. (Level of Evidence: A)