Medical Device Daily

Neurostimulation technology is being used to treat a host of conditions, including epilepsy, Parkinson’s disease, stroke, depression and chronic pain of the arms, legs and trunk. Now, St. Jude Medical (St. Paul, Minnesota) is attempting to bring this technology to the U.S. for the treatment of chronic chest pain caused by angina.

St. Jude last week reported the first patient implant in a pilot study that will provide preliminary evaluation of the ability to stimulate the nerves near the spinal cord to control chronic angina chest pain.

A 53-year-old Massachusetts woman was the first person to receive this investigational device, called the Genesis neurostimulation system. She is one of the 1.3 million Americans — estimated by the American Heart Association (Dallas) — who suffer from chronic angina, with 75,000 new cases of treatmen resistant angina each year.

The Genesis system was developed by St. Jude Medical’s neuromodulation division, Advanced Neuromodulation Systems (ANS; Plano, Texas), which last month had two tripolar leads FDA-cleared for use on its Renew neurostimulation system for the treatment of neuropathic low back pain (Medical Device Daily, Feb. 21, 2007).

“The procedure went smoothly,” said Thomas Simopoulos, MD, interventional pain specialist with the Arnold Pain Management Center at Beth Israel Deaconess Medical Center, who performed the implant. “I am hopeful that spinal cord stimulation will offer a minimally invasive treatment option for patients with chronic, intractable angina.”

According to Rohan Hoare, VP, strategy and emerging therapies for ANS, spinal cord stimulation (SCS) for the treatment of angina has been used extensively in Europe “for a number of years,” and used in the U.S. for some time, but primarily in off-label applications.

He told Medical Device Daily that in Europe doctors have been treating angina with neurostimulation technology “on the order of 15 to 20 years.”

While it’s still too early to tell exactly where SCS will ultimately fit within the angina treatment pantheon, data from the Electrical Stimulation Bypass Surgery (ESBY) trial — which was published in Circulation in 1998 — suggested that SCS may be a therapeutic alternative for patients with an increased risk of surgical complications and no prognostic benefit from surgery.

In the ESBY trial, SCS was investigated as an alternative to coronary artery bypass grafting (CABG) in patients with no proven prognostic benefit from CABG and with an increased surgical risk.

The 104-patient study (SCS, 53; CABG, 51) showed that CABG and SCS appeared to be equivalent methods in terms of symptom relief in this group of patients.

While Hoare said that the Genesis is primarily intended to alleviate the pain associated with an anginal attack, he noted that there is some evidence from the European literature that it may have some prophylactic benefit as well. “So that you not only alleviate the pain of an attack but you actually reduce the frequency of the attack, so you get a benefit two ways,” Hoare said.

The Genesis functions much like the Renew system used for back pain, with one distinctive difference; the Genesis uses an internal battery instead of relying on an external power source as the Renew does.

Hoare said that the Renew is very useful in situations where a larger power supply is needed for a treatment, however, the angina indication does not require as large an energy source, thus allowing the power supply to be completely internalized.

“The Genesis is very well-suited towards a spinal cord stem application for angina,” he said.

To be eligible for enrollment in the newly launched pilot study of the Genesis system — the study not being given the standard clever acrynomed name, Hoare told MDD — patients must be at least 18 years old, have been diagnosed with inoperable coronary artery disease, and be experiencing a minimum of five angina episodes per week. Patients must also be diagnosed with functional class III or class IV angina, categorized according to the Canadian Cardiovascular Society scale.

The study, a controlled, masked pilot, is being conducted under an FDA investigational device exemption (IDE).

While Hoare declined to provide further details about the trial, he noted that “angina is a long-term condition and basically I think that you need to sort of view this as a long-term therapy to help a patient with this condition.”

Angina is chest pain or discomfort results when the heart does not get as much oxygen as it needs. The pain is often described as a squeezing pain in the chest, shoulders, arms, neck, jaw or back and is sometimes described as feeling like indigestion. Angina is one of the most common symptoms of coronary artery disease which is a leading cause of death in the U.S.

Chronic angina is chest pain that persists. Many people with this condition have to live with constant or recurring pain and loss of function. For a number of these people, medications such as nitroglycerin do not work, and surgical procedures such as angioplasty, stenting or bypass, are considered to be too risky by their doctors.

“There are an increasing number of patients with coronary artery disease who have exhausted available medical and surgical treatment options,” said Roger Laham, MD, interventional cardiologist with Harvard Medical School and Beth Israel Deaconess Medical Center (both Boston), the principal investigator for the trial. “These patients struggle with disabling angina and are commonly referred to as ‘no-option’ patients.”