John Digiacinto was sitting at his desk a couple of months ago when his right arm went limp. His wife drove him to a hospital near his office in Redwood City, Calif., where an MRI revealed a big problem: a tear inside his carotid artery.

"A physician, a vascular surgeon, told me the best thing I could do was get to Stanford Hospital," recalled the 61-year-old defense attorney. An ambulance took him there, and he was put under the care of Michael Marks, MD, one of the world's leading interventional neuroradiologists. 

Digiacinto's carotid artery, which runs up the left side of the neck and supplies blood to the brain, had dissected: A segment of the innermost lining was torn, creating a pocket where blood was pooling inside the wall of the vessel. 

Carotid dissections can narrow the artery, choking off blood to the brain, or cause clots, leading to a fatal stroke. Such injuries, however, are relatively rare. They are usually caused by trauma, ranging from a hard blow to the neck or whiplash to, occasionally, a monumental sneeze. A very small portion of the population — less than two to three people per 100,000 — suffer spontaneous carotid dissections. Symptoms can be as subtle as a headache or as conspicuous as the loss of consciousness.

Digiacinto, executive director of the San Mateo County Bar Association and longtime head of the county's private defender program, did not suspect that the odd symptoms he had experienced over the previous two days pointed to anything life-threatening. 

The trouble began in the late afternoon of March 9, when the keys he was holding in his right hand slipped from his grasp. He was in the hallway of the bar association offices. Earlier, his left eye had been aching, but that didn’t strike him as unusual; he spent a lot of time staring into a computer screen, reading and composing documents.

He picked up his keys and continued down the hall. Once again, he dropped them. He picked them up. Then he collapsed. A colleague rushed to help, but Digiacinto recovered quickly, and a visit to a local emergency department revealed nothing out of the ordinary.

A couple of days later, his right arm went limp.

Marks, who is chief of interventional neuroradiology at Stanford Hospital and a professor of radiology at the School of Medicine, studied an MRI of Digiacinto's head and neck, and was struck by the length of the tear, which spiraled almost 4 inches into the base of the skull.

"The artery was basically as badly affected as it could be and still remain open," Marks said.

A special blood-flow test, developed by Stanford radiologists to measure the quantity of circulation to the brain, also yielded troubling results. "It showed that an extensive region of the left part of his brain was getting poor levels of perfusion," Marks said.

Meanwhile, Digiacinto’s symptoms—decreased motor strength and impaired language function—were getting worse. Often, a blood thinner is enough to protect against clots and allow the dissected artery to heal. But Digiacinto's case was too severe. Marks decided it was urgent that stents—tiny mesh tubes that can be expanded to prop open blood vessels—be placed along the injured segment of the artery. They could push the torn lining back against the artery wall.

"I remember thinking that we really needed to get that blood vessel open but also that we didn’t want to risk dislodging a blood clot or mistakenly pushing the stent into the dissection, which could block blood flow entirely," Marks said.

He faced another particular challenge: He would have to place one stent in a roughly 90-degree turn where the artery ascends and narrows through a canal in the base of the skull, following a path that looks a little like a sideways "Z." Manipulating a thin, flexible guide wire from a puncture in the femoral artery in Digiacinto's thigh, Marks began to work.

After three hours in Stanford's catheterization lab, he succeeded in lining up three, carefully overlapping stents that now ran a full six inches along Digiacinto's carotid artery. "This was the longest carotid dissection I've treated," said Marks, who has practiced at Stanford for 23 years.

How Digiacinto tore the artery remains a mystery. Nationwide, dissections of the carotid and vertebral arteries cause about 2 percent of strokes, though they are responsible for roughly a quarter of all strokes among people who are young or middle-aged. Fortunately, most patients with such a dissection respond to blood-thinning medication and will heal. However, some will require treatment to repair the artery because the medication is not doing enough to help.

It took four days for Digiacinto’s strength and language ability to return and for him to be released from the hospital. He went straight back to work. "Dr. Marks is a miracle worker," Digiacinto said, adding that he was "beyond grateful" for the treatment he received at Stanford Hospital.

"I feel like a million bucks," he said.

By John Sanford