Cardiology- Day 13

ASA in Primary Prevention:

CHEST 2008
- Grade 2A: benefit vs risks is unclear, based on RCTs that do not have important limitations
- for pt with at least moderate risk for coronary event ( based on age and cardiac risk factor profile with a 10 year risk of cardiac event greater than 10%), we recommend 75-100 mg daily of AS over either no antithrombotic therApy or VKA
ACC- 2002 Primary Prevention Guidelines
- low dose aspirin in persons at higher CHD risk ( especially those with 10 y risk of CHD greater than 10%)
- recommended for pt especially if moderate to high risk should be on ASA for primary prevention
ACC UA/STEMI 2007 Guidelines
- asa prophylaxis can uncommonly result in hemorrhagic complications and should ony be sued in primary prevention when the level of risk justifies it. Patients whose 10 y risk of CHD is 10% or more are most likely to benefit and 75-162 mg of ASA per day as primary prophylaxis should be discussed

LMWH Dosing in Renal Impairment

Renal Drug Dosing Handbook: decrease LMWH b y50% if eGFR is less than 10%
Enoxaparin
CrCl less than 30 mL/min: unfractionated heparin recommended instead of LMWH; if LMWH is used, reduce usual recommended dose by 50% (guideline dosing)
CrCl less than 30 mL/min: ST-segment elevation MI (age less than 75 yr): 30 mg IV bolus plus 1 mg/kg subcutaneously followed by 1 mg/kg subcutaneously once daily

CrCl less than 30 mL/min: ST-segment elevation MI (age 75 yr or older): 1 mg/kg subcutaneously once daily without a bolus dose
dalteparin
- renal impairment: (thromboprophylaxis) 5000 units fixed dose (range 2500 units to 7500 units) SUBQ daily did not result in drug accumulation in patients with mild to severe renal impairment

LMWH vs UFH in STEMI

EXTRACT- TIMI 25 ( NEJM 2006)

N= 20506, STEMI X 6 h and fibrinolysis
UFH X 48 h vs enoxaparin x 8 days

FMI

dc bb in coronary vasospasm
- bb prevent smooth muscle relaxation
- alpha is uninhibited by beta receptor–> further vasoconstriction

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