DISEASE INFLUENCING FACTORS : DIET, LIFE STYLE, ENVIRONMENT, SMOAKING, ALCOHOL, DRUG ABUSE & LACK OF EXERCISE, POSITIVE FAMILY HISTORY, HYPERTENSION, DIABETES MELLITUS & CHR RENAL DISEASE
Medical Care: Initial therapy for acute MI is directed toward restoration of perfusion in order to salvage as much of the jeopardized myocardium as possible. This may be accomplished through medical or mechanical means, such as angioplasty or coronary artery bypass grafting.
Further treatment is based on (1) restoration of the balance between the oxygen supply and demand to prevent further ischemia, (2) pain relief, and (3) prevention and treatment of any complications that may arise.
" Thrombolytic therapy has been shown to improve survival rates in patients with acute MI if administered in a timely fashion in the appropriate group of patients. If PCI capability is not available or will cause a delay greater than 90 minutes, then the optimal approach is to administer thrombolytics within 12 hours of onset of symptoms in patients with ST-segment elevation greater than 0.1 mV in 2 or more contiguous ECG leads, new left bundle-branch block (LBBB), or anterior ST depression consistent with posterior infarction. Tissue plasminogen activator (t-PA) is superior to streptokinase in achieving a higher rate of coronary artery patency; however, the key to efficacy lies in the speed of the delivery of therapy. Recent trials show a high patency rate if a IIb/IIIa receptor antagonist is combined with a half dose of a thrombolytic agent as the initial reperfusion strategy. The reduced dose of a thrombolytic agent combined with a potent platelet inhibitor may prove to be the preferred method for medical
reperfusion. Larger clinical trials are pending.
" Aspirin and/or antiplatelet therapy
o Aspirin has been shown to decrease mortality and re-infarction rates after MI. Administer aspirin immediately, which the patient should chew if possible upon presentation. Continue aspirin indefinitely unless an obvious contraindication, such as a bleeding tendency or an allergy, is present. Clopidogrel may be used as an alternative in cases of a resistance or allergy to aspirin. Recent data from the CLARITY trial (CLopidogrel as Adjunctive ReperfusIon Therapy Thrombolysis in Myocardial Infarction [TIMI] 28) suggest that adding clopidogrel to this regimen is safe and effective. The clopidogrel dose used was 300 mg.
o Administer a platelet glycoprotein (GP) IIb/IIIa-receptor antagonist, in addition to acetylsalicylic acid and unfractionated heparin (UFH), to patients with continuing ischemia or with other high-risk features and to patients in whom a percutaneous coronary intervention (PCI) is planned. Eptifibatide and tirofiban are approved for this use. Abciximab also can be used for 12-24 hours in patients with unstable angina or NSTEMI in whom a PCI is planned within the next 24 hours.
" Beta-blockers reduce the rates of reinfarction and recurrent ischemia and possibly reduce the mortality rate if administered within 12 hours after MI. Administer routinely to all patients with MI unless a contraindication is present.
" Heparin (and other anticoagulant agents) has an established role as an adjunctive agent in patients receiving t-PA but not with streptokinase. Heparin is also indicated in patients undergoing primary angioplasty. Little data exist with regard to efficacy in patients not receiving thrombolytic therapy in the setting of acute MI. Low-molecular-weight heparins (LMWHs) have been shown to be superior to UFHs in patients with unstable angina or NSTEMI.
" Nitrates have no apparent impact on mortality rate in patients with ischemic syndromes. Their utility is in symptomatic relief and preload reduction. Administer to all patients with acute MI within the first 48 hours of presentation, unless contraindicated (ie, in RV infarction).
" ACE inhibitors reduce mortality rates after MI. Administer ACE inhibitors as soon as possible as long as the patient has no contraindications and remains in stable condition. ACE inhibitors have the greatest benefit in patients with ventricular dysfunction. Continue ACE inhibitors indefinitely after MI. Angiotensin-receptor blockers may be used as an alternative in patients who develop adverse effects, such as a persistent cough, although initial trials need to be confirmed.
Surgical Care:
" Percutaneous coronary intervention
o PCI is the treatment of choice in most patients with STEMI, assuming a door to needle time of less than 90 minutes. PCI provides greater coronary patency (>96% thrombolysis in myocardial infarction [TIMI] 3 flow), lower risk of bleeding, and instant knowledge about the extent of the underlying disease. Studies have shown that primary PCI has a mortality benefit over thrombolytic therapy.
o The choice of primary PCI should be individualized to each institution and to the patient's presentation and timing.
o The widespread use of stenting and adjunctive IIb/IIIa therapy are improving the results of primary PCI. A recently published trial showed that, in patients with acute MI, coronary stenting and abciximab lead to a greater degree of myocardial salvage and a better clinical outcome than fibrinolysis with thrombolytic therapy. Improvement of long- and short-term outcomes, however, depends highly on the speed with which reperfusion is achieved.
o Primary PCI is also the treatment of choice in patients with cardiogenic shock, patients in whom thrombolysis failed, and those with high risk of bleeding or contraindications to thrombolytic therapy.
o Only an experienced operator should perform primary PTCA, and PTCA should be performed only where the appropriate facilities are available. Operators should have at least 75 cases per year, while the center should perform at least 200 cases per year as per the recommendations of the ACC.
" Emergent or urgent coronary artery graft bypass surgery is indicated in patients in whom angioplasty fails and in patients who develop mechanical complications such as a VSD, LV, or papillary muscle rupture.
Diet:
" Initially, keep the patient on nothing by mouth (NPO) until his or her condition has been stabilized and treated. Following initial therapy and admission, a dietitian should instruct the patient regarding appropriate diet, as recommended by the AHA.
" A low-salt, low-fat, and low-cholesterol diet is generally recommended.
Activity:
" Confine patients to bed rest to minimize oxygen consumption until reperfusion and initial therapy are complete. This usually lasts about 24-48 hours; after that, the patient's activity may be accelerated slowly as tolerated and as the clinical situation allows.
" Initiate cardiac rehabilitation prior to discharge.
DRUG TREATMENT :
1. SALICYLATES :
- ASPIRIN
2. VASODILATORS :
- NITROGLYCERIN
3. ANALGESICS :
- MORPHINE SULPHATE
4. ANTICOAGULANTS :
- HEPARINE
- LOW MOLECULAR WEIGHT HEPARIN : ENOXAPARIN
5. THROMBOLYTICS :
- ALTEPLASE
- STREPTOKINASE
- RETEPLASE
- ANISTREPLASE
6. BETA BLOCKERS :
- METOPROLOL
- ESMOLOL
7. ACE INHIBITORS :
- CAPTOPRIL
8. PLATELET AGGREGATION INHIBITORS :
- ABCIXIMAB
- TIROFIBAN
- EPTIFIBATIDE
PROGNOSIS :
PTS WITH REDUCED LV FUNCTION ( EF < .30 ) AT LEAST 1 MTHFOLOWING ACUTE MI, OR WHO HAVE HEMODYNAMICALLY SIGNIFICANT VENTRICULAR ARRHYTHMIAS MORE TAHN 2 DAYS AFTER M.I. , HAVE INDICATION FOR IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR ( ICD ) DUE TO HIGH RISK OF SUDDEN CARDIAC DEATH FROM MALIGNANT VENTRICULAR ARRHYTHMIAS.
COMPLICATIONS :
- VENTRICULAR SEPTAL RUPTURE
- MITRAL REGURGITATION
- CARDIAC RUPTURE
- PSEUDOANEURYSM
- CARDIOGENIC SHOCK
- RV FAILURE FOLLOWING INFERIOR WALL INFACTION
- VENTRICULAR ANEURYSM
- ARRHYTHMIAS
- PERICARDITIS
ALTERNATIVE DRUGS
. Thrombolytics
. Tenecteplase or reteplase
. Beta-blockers for acute arrhythmia
. Atenolol 5 mg IV over 5 minutes. Follow with a second dose 10 minutes later. Follow with 50 mg po in 10 minutes after the 2nd IV dose. Then q12h for at least 7 days
PATIENT MONITORING
β’ Determined by needs of patient
β’ Early intervention if any one of the following: recurrent chest pain, CHF, hemodynamic instability, sustained
V-tach, PCI within 6 months, prior CABG
PREVENTION/AVOIDANCE
β’ Avoid risk factors
β’ Aspirin 81 mg/day may be helpful
β’ Clopidogrel 75 mg day
POSSIBLE COMPLICATIONS
β’ Congestive heart failure
β’ Cardiogenic shock
β’ Myocardial rupture
β’ Left ventricular aneurysm
β’ Left ventricular thrombus and peripheral embolism
β’ Deep venous thrombosis and pulmonary embolism
β’ Pericarditis
β’ Dysrhythmias
β’ Mitral regurgitation
β’ Ventricular septal defect
β’ Dresslerβs syndrome
β’ Cardiac arrest
β’ Death