Surgery on blocked neck arteries has long been considered the best procedure for preventing a stroke. Now a large North American study has found that a less invasive approach may be just as safe and effective, but other researchers are not so sure. Readers' Comments The findings, released Friday at a medical meeting in San Antonio, have the potential to make the less invasive procedure — inserting a small tube called a stent in the carotid artery — a more appealing option for many patients. Yet just a day earlier, European investigators reported dismal results from another international trial involving carotid stents, published online Thursday by the British medical journal The Lancet. In that study, patients treated with stents suffered almost double the rate of complications as those treated surgically, leading the British researchers to conclude that surgical treatment of carotid blockages, called endarterectomy, remains the treatment of choice.