Treatment and prevention strategies have included use of the GP IIb/IIIa antagonist abciximab, vasodilators (nitroprusside, vera- pamil, adenosine), and inhibitors of various metabolic path- ways (nicorandil, pexelizumab), albeit without consistent effect. Manual thrombus aspiration at the time of primary PCI results in improved tissue perfusion and more complete (Section 4.2), though not all studies have shown positive results.223 PCI of a noninfarct artery with TIMI 3 flow at the time of primary PCI in hemodynamically stable patients has been associated with worse clinical outcomes in several stud- though others have suggested that it may be Noninfarct artery PCI is not recom- mended in this context unless multiple complex lesions are seen on angiography and ECG localization of the infarct is Clinical stability may be defined broadly as the absence of low output, hypotension, persistent tachycar- dia, apparent shock, high-grade ventricular or symptomatic supraventricular tachyarrhythmias, and spontaneous recurrent ischemia. In patients with cardiogenic shock due to pump fail- ure, PCI of a severe stenosis in a large noninfarct artery might improve hemodynamic stability and should be considered dur- ing the primary procedure (Section 9.1.1). In the majority of patients, delayed PCI can be performed in a noninfarct artery at a later time if indicated by clinical events or the results of 4.2. Aspiration Thrombectomy: Recommendation Class IIa 1. Manual aspiration thrombectomy is reasonable for patients undergoing primary PCI.221,223,234,235 (Level of Evidence: B) and a meta-analysis234 support the use of man- ual aspiration thrombectomy during primary PCI to improve microvascular reperfusion and to decrease deaths and adverse cardiac events. 