Alberts and colleagues are involved in ongoing research looking at other markers of aspirin resistance and are planning a study examining dose-adjusted PFA tests.

"In other words, we'll be changing someone's antiplatelet medication to get a therapeutic PFA and see whether this translates into efficacy and safety," Alberts explains. Other studies looking at clopidogrel resistance are also essential, he says. "Clopidogrel resistance is another area of growing concern that has only recently been identified, and it's unclear how common it is or what the clinical significance is and whether it can be overcome by using higher doses of clopidogrel, which are not FDA approved for routine use at this point," he adds.

For the time being, physicians should not rely solely on daily aspirin for stroke prevention, the investigators say. "Physicians need to pay attention to other risk-factor identification and modification for factors we know can make a difference in reducing the risk of stroke," Alberts says. "Things like hypertension, hyperlipidemia, smoking, exercise, and diet."

In the future, aspirin-resistance tests may help improve patient outcomes, but Alberts warns that much more comprehensive studies are warranted. "We need to find out whether or not we can use the results of PFA testing as a guide to determine how to treat these patients, and if the numbers actually predict clinical events, both on the efficacy side and on the safety side," Alberts stated. "The concern is that if you give patients more antiplatelet agents, you could have more bleeding side effects. So we need to be aware of both sides of this coin."