Taking low-dose aspirin daily has been touted for years to lower the risk of heart attack and stroke. Some people show resistance to this therapy in blood tests, but why?

After certain types of heart attacks, doctors often use stents to prop open the arteries. Another method that may be used involves removing blood clots through thrombus aspiration (TA), but studies have shown mixed long-term results.

After an artery-opening procedure following a heart attack, some patients take Plavix ( clopidogrel ) to treat or prevent a blood clot. Though the drug isn't as effective in some individuals, genetic testing is not needed, a recent study suggests.