Part 8: Stabilization of the Patient With Acute Coronary Syndromes Iv-97 TABLE 4. TIMI Risk Score for Patients With Unstable Angina and Non-ST-Segment Elevation ME: Predictor Variables Point value Predictor Variable of variable Definition Age 265 ≥3 risk factors for CAD Risk factors Family history of CAD Hypercholesterolemia Diabetes Current smoker Aspirin use in last 7 days Recent, severe symptoms of angina 22 anginal events in last 24 hours Elevated cardiac markers CK-MB or cardiac-specific troponin level st deviation≥0.5 ST depression 20.5 mm is significant; transient sT elevation >0.5 mm for <20 minutes is treated as sT-segment depression and is high risk; sT elevation 21 mm for more than 20 minutes places these patients in the STEMI treatment category Prior coronary artery stenosis 250% Risk predictor remains valid even if this information is unknown Risk of≥1 Primary End Calculated TIMI Risk Score Point* in≤14Days Risk Status 0 or 1 13% Primary end points: death, new or recurrent Mi, or need for urgent revascularization. managed with an invasive strategy. Coronary angiography monitoring, establishment of intravenous(Iv) access, and then allows the clinician to determine whether patients are several medications discussed below appropriate candidates for revascularization with PCi or coronary artery bypass grafting(CABG) Oxygen The 2005 AHA Guidelines for CPR and ECC define Administer oxygen to all patients with overt onary high-risk patients with indicators that overlap to a consider- congestion or arterial oxygen saturation <90%(Class I). It is able degree with the more rigorously validated TIMI risk also reasonable to administer to all patients with ACS for the first 6 hours of therapy( Class Ila) New ST-segment depression and positive troponins Supplementary oxygen limited ischemic myocardial injury in Persistent or recurrent symptoms animals, I and oxygen therapy in patients with STEMI Hemodynamic instability or VT reduced the amount of ST-segment elevation. 5 Although Depressed LV function(ejection fraction <40%0) human trial of supplementary oxygen versus room air failed ECG or functional study that suggests multivessel CAD to show a long-term benefit of supplementary oxygen therapy for patients with MI, O short-term oxygen administration is Normal or Nondiagnostic ECG Changes(Boxes 13 beneficial for the patient with unrecognized hypoxemia o to 17) unstable pulmonary function. In patients with severe chronic The majority of patients with normal or nondiagnostic ECGs obstructive pulmonary disease, as with any other pater do not have ACS Patients in this category with ACS are most monitor for hypoventilation often at low or intermediate risk. The physician's goal involves risk stratification(see above)to provide appropriate AsI diagnostic or treatment strategies for an individual patient. Early administration of aspirin(acetylsalicylic acid [ASAD). These strategies then target patients at increased risk for including administration in the out-of-hospital setting, ha benefit while avoiding risk(eg, anticoagulation therapy an been associated with decreased mortality rates in several invasive cardiac catheterization)in patients with low or clinical trials.47129-131 Multiple studies s pport the safety of minimal risk aspirin administration. Therefore, unless the patient has a known aspirin allergy, nonenteric aspirin should be given as I General Therapy for ACs soon as possible to all patients with suspected ACs. Several initial measures are appropriate for all patients with Aspirin produces a rapid clinical antiplatelet effect with suspected ACS in both the out-of-hospital and ED setting. near-total inhibition of thromboxane A2 production. It reduces These include immediate oxygen therapy, continuous cardiac coronary reocclusion and recurrent ischemic events aftermanaged with an invasive strategy. Coronary angiography then allows the clinician to determine whether patients are appropriate candidates for revascularization with PCI or coronary artery bypass grafting (CABG). The 2005 AHA Guidelines for CPR and ECC define high-risk patients with indicators that overlap to a consider￾able degree with the more rigorously validated TIMI risk score122: ● New ST-segment depression and positive troponins ● Persistent or recurrent symptoms ● Hemodynamic instability or VT ● Depressed LV function (ejection fraction 40%) ● ECG or functional study that suggests multivessel CAD Normal or Nondiagnostic ECG Changes (Boxes 13 to 17) The majority of patients with normal or nondiagnostic ECGs do not have ACS. Patients in this category with ACS are most often at low or intermediate risk. The physician’s goal involves risk stratification (see above) to provide appropriate diagnostic or treatment strategies for an individual patient. These strategies then target patients at increased risk for benefit while avoiding risk (eg, anticoagulation therapy and invasive cardiac catheterization) in patients with low or minimal risk. Initial General Therapy for ACS Several initial measures are appropriate for all patients with suspected ACS in both the out-of-hospital and ED setting. These include immediate oxygen therapy, continuous cardiac monitoring, establishment of intravenous (IV) access, and several medications discussed below. Oxygen Administer oxygen to all patients with overt pulmonary congestion or arterial oxygen saturation 90% (Class I). It is also reasonable to administer supplementary oxygen to all patients with ACS for the first 6 hours of therapy (Class IIa). Supplementary oxygen limited ischemic myocardial injury in animals,31 and oxygen therapy in patients with STEMI reduced the amount of ST-segment elevation.35 Although a human trial of supplementary oxygen versus room air failed to show a long-term benefit of supplementary oxygen therapy for patients with MI,30 short-term oxygen administration is beneficial for the patient with unrecognized hypoxemia or unstable pulmonary function. In patients with severe chronic obstructive pulmonary disease, as with any other patient, monitor for hypoventilation. Aspirin Early administration of aspirin (acetylsalicylic acid [ASA]), including administration in the out-of-hospital setting,47 has been associated with decreased mortality rates in several clinical trials.47,129 –131 Multiple studies support the safety of aspirin administration. Therefore, unless the patient has a known aspirin allergy, nonenteric aspirin should be given as soon as possible to all patients with suspected ACS. Aspirin produces a rapid clinical antiplatelet effect with near-total inhibition of thromboxane A2 production. It reduces coronary reocclusion and recurrent ischemic events after TABLE 4. TIMI Risk Score for Patients With Unstable Angina and Non–ST-Segment Elevation MI: Predictor Variables Predictor Variable Point Value of Variable Definition Age 65 years 1 3 risk factors for CAD 1 Risk factors • Family history of CAD • Hypertension • Hypercholesterolemia • Diabetes • Current smoker Aspirin use in last 7 days 1 Recent, severe symptoms of angina 1 2 anginal events in last 24 hours Elevated cardiac markers 1 CK-MB or cardiac-specific troponin level ST deviation 0.5 mm 1 ST depression 0.5 mm is significant; transient ST elevation
0.5 mm for 20 minutes is treated as ST-segment depression and is high risk; ST elevation 1 mm for more than 20 minutes places these patients in the STEMI treatment category Prior coronary artery stenosis 50% 1 Risk predictor remains valid even if this information is unknown Calculated TIMI Risk Score Risk of >1 Primary End Point* in <14 Days Risk Status 0 or 1 5% Low 2 8% 3 13% Intermediate 4 20% 5 26% High 6 or 7 41% *Primary end points: death, new or recurrent MI, or need for urgent revascularization. Part 8: Stabilization of the Patient With Acute Coronary Syndromes IV-97