Prior to his stroke, Sean Maloney, a lifelong athlete who maintained a healthy diet and lifestyle and had yearly medical checkups, was not considered at high risk.

"Sean was more fit than I was, and I'm pretty fit," Margaret Maloney said. "But some people are more prone to plaque buildup."

Nearly 800,000 Americans each year experience a stroke, costing 128,000 lives and $73.7 billion in medical and disability costs. And yet 80 percent of strokes and heart attacks are preventable, according to the American Heart Association and the American Stroke Association.

Key things people can do to minimize their risk of stroke are to control their blood pressure, avoid smoking, get 30 minutes of exercise most days of the week and talk to their primary-care physicians about the need for medications such as aspirin or cholesterol-lowering drugs, Stanford University neurologist Maarten Lansberg said.

People also should learn the symptoms of stroke (face drooping, arm weakness, speech difficulty) and get a victim to the emergency room immediately, he said.

Maloney would add an additional recommendation for stroke prevention, one that is currently not standard practice among primary-care physicians: Get a carotid artery ultrasound if you are over 40 to determine whether there is blockage or narrowing in the arteries. Had he been given such a scan in the months prior to the event, Maloney believes his stroke would not have happened.

"If you don't get an ultrasound, you don't know whether or not you have the problem," he said.

San Jose resident Victoria Dupuy, whose husband Dean, a 46-year-old Apple engineering manager, collapsed and died of a heart attack in 2013 while playing ice hockey, echoes Maloney's plea for wider use of scanning technology as a preventive screening measure. Dean Dupuy had gone for his annual checkups, had no known risk factors and, just hours before his collapse, happily completed a "muddy buddy" running and bicycling obstacle course with his teenage daughter.

His widow has launched "No More Broken Hearts," a nonprofit group aimed at creating awareness about why seemingly healthy people have heart attacks and the need for heart screenings even in low-risk, asymptomatic individuals.

"Heart attacks occur without warning to even those who have no symptoms of heart disease and appear very healthy," Victoria Dupuy said. "At No More Broken Hearts, we want to see a world where these screenings are a routine part of one's physicals, just like mammograms and colonoscopies."

But current medical guidelines do not recommend carotid-artery ultrasound for asymptomatic individuals, neurologist Lansberg said.

"If you have already had a stroke or TIA (transient ischemic attack, or mini-stroke) it is important to get your carotid arteries checked because early treatment of blocked carotid arteries (a surgery called carotid endarterectomy, or CEA) can help prevent a second stroke," he said.

"If you have not had a stroke or TIA, current guidelines do not recommend screening for carotid stenosis (narrowing) with carotid-artery ultrasound because it is uncertain if patients with so-called 'asymptomatic' carotid stenosis benefit from (the surgery) or carotid stenting."

However, the National Institutes of Health is currently funding a trial to determine whether asymptomatic individuals who have taken the ultrasound and been diagnosed with carotid-artery stenosis could benefit from the surgery or carotid stenting over the standard medical treatment, Lansberg said.

The trial is called the Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Study, or CREST-2. For more information, go to crest2trial.org.

If you're going

Victoria Dupuy, director of No More Broken Hearts, invites the public to a free showing of "The Widowmaker," a 2014 documentary that promotes the coronary calcium scan, a screening that Dupuy believes would have saved her husband's life. The movie will be screened on Saturday, March 21, at 11 a.m. at the Guild Theatre in Menlo Park. For more information, call 650-566-8367.