Medical Device Daily Contributing Writer
Franklin Square Hospital Center (Baltimore) hosted a live webcast last month of a carotid artery stenting surgery. Carotid artery stenting is a new minimally invasive therapy recently approved by the FDA for the prevention of stroke.
Currently, most blockages in the carotid artery are treated with the surgical procedure known as carotid endartarectomy, in which surgeons cut into the neck artery to remove the blockage. Patients require general anesthesia for that procedure.
In carotid stenting, a physician uses a combination of balloon angioplasty and placement of a stent to unblock and reopen the carotid artery to help prevent strokes. Because the procedure doesn’t require anesthesia, it is recommended for patients with a weak heart, diminished lung capacity or other high-risk conditions. The patient is awake throughout the procedure.
The event was moderated by Daniel Picard, MD, vascular surgeon and chairman of the department of surgery at Franklin Square, while the surgery was performed by George Jabaji, MD, chief of vascular surgery at the hospital.
According to Picard, “Recent research has indicted that the new stent system, manufactured by Guidant [Indianapolis], successfully opened blockages in 92% of patients. In addition, the study showed that the stent still allowed blood flow to the brain more than two years post-operatively.”
The Centers for Medicare & Medicaid Services (Baltimore) will reimburse for this procedure only if the patient is at “high risk” for stroke and older than 79.
The patient was a 74-year-old man at high risk because of major medical problems. He presented with an 80% occlusion of the left common carotid artery just before it bifurcates into the internal carotid artery. An incision was made into the left femoral artery and a wire was placed up into the left common carotid artery. Then a shuttle sheath was placed over that wire and the patient was treated with heparin.
A protective miniature umbrella device was then advanced over a 0.14” wire (the rail). The tightly shut umbrella was advanced through and beyond the occlusion. An angiogram was taken, providing a “road map” for the progression of the procedure. Under fluoroscopy, markers along the wire showed its progression into the internal carotid.
Jabaji then deployed the umbrella, opening it up via a torque device at the femoral end of the insertion wire. The membrane in the umbrella allows blood to flow through, but it traps tiny pieces of plaque and clots that are inevitably loosened from the inside of the artery during the surgery.
Jabaji then performed a traditional balloon angioplasty to open the diameter of the carotid vessel at its point of occlusion. This was done to be sure the stent could be passed. The balloon was 4 mm in diameter and 4 cm in length.
A viewer asked, “Can the patient actually suffer a stroke as a result of this procedure?” “Yes,” answered Picard. “But that’s why we use this embolism protection umbrella. When we use this device, we see about 2.4% incidence of complications. Without it, 5.2%.”
Jabaji then demonstrated the deployment of the flexible expandable stent. Made of Nitinol (nickel and titanium), it expands with the body’s temperature. The stent was moved through the lesion in the common carotid artery and on into the internal carotid. Occasionally, when the lesion is long, more than one stent is required and they are placed in an overlapping fashion.
Another e-mailed question: “Is this a drug-eluting stent?” Pickard answered, “We are not yet using drug-eluting stents in the carotid or peripheral vascular arteries. They’ve only so far been approved for the coronary arteries of the heart.”
Back at the OR table, Jabaji removed the deployment sheath and expanded the stent using a control at the end of the wire transporting the stent. The patient felt pressure in his neck as the balloon was being used to dilate the inside of the stent to complete its expansion. At the completion of the deployment, Jabaji showed comparison angiograms before the procedure where an 80% occlusion could clearly be seen and post-stenting where the occlusion was 15% to 20%. Jabaji said, “The stent will continue to expand over the next few hours until it reaches its maximum diameter.”
From the audience: “Will this patient have to be on medication for the rest of his life?” Pickard noted, “Not Coumadin or Plavix [both from Bristol-Meyers Squibb; New York]. We keep the patient on Plavix and aspirin for about a month. Then they stay on aspirin for the rest of their life.”
Satisfied with the stent placement, Jabaji reinserted a sheath through the stent to close the protective umbrella and remove it. Tiny of pieces of loose plaque had been captured and were removed inside the closed umbrella.
A heparin flush was completed and the surgeons closed the femoral access using the Perclose device from Abbott Vascular (Redwood City, California). This technique allows patients to ambulate more quickly. Two needles are automatically placed through the arteriotomy and the stitch is tied outside the wound. A knot pusher is used to secure the stitch and a blade cuts the thread. The procedure was completed in under an hour.
Pickard noted, “The advantages to this procedure are mild sedation instead of general anesthesia and almost no recovery time. This is an outpatient procedure and the patient can return to normal activity immediately.”
There are two situations in which a patient may be recommended for carotid artery surgery. One is where there are symptoms: motor deficiencies, speech or sensory deficiencies or ocular symptoms. The second is where a nonsymptomatic patient is found to have a “bruit” or noise in the carotid heard through a stethoscope. This finding is confirmed with duplex ultrasound.
Risk factors for carotid artery occlusion are those of any atherosclerosis-related disease. They include smoking, hypertension, diabetes, 50-plus years of age and a family history of atherosclerosis.