Full clinical trial feasible in refractory chronic angina pectoris

Results of the world's first publicly funded randomized controlled clinical trial of spinal cord stimulation, being presented today at the 12th World Congress of the International Neuromodulation Society, conclude that a fully powered clinical trial is feasible in refractory chronic angina pectoris, a disabling and persistent chronic pain condition.

The multi-center randomized, controlled feasibility and pilot study was funded in 2010 by the National Institute for Health Research. The study completed in 2014, "Refractory Angina Spinal Cord stimulation and usuAL care" (RASCAL), compared management of refractory chronic angina pectoris using spinal cord stimulation (SCS) vs. usual care alone. It was funded in the wake of a NICE (National Institute for Health and Care Excellence) recommendation in 2008 that called for a pragmatic U.K.-based trial of SCS in refractory chronic angina pectoris.

Chronic angina pectoris patients experience severe pain upon even mild exertion as a consequence of their nerve endings having become hypersensitized due to restricted blood flow (ischemia). The condition leads to frequent hospitalization and poor health-related quality of life. NICE recommended SCS for ischemic conditions in 2008, but on a research-only basis.

"There is a need for large, high-quality research studies to clarify the role of spinal cord stimulation in the treatment continuum for chronic angina pectoris, which may not respond sufficiently to pharmaceuticals and for which revascularization procedures may not be feasible or the risk unjustified," commented senior author Sam Eldabe, MD, of James Cook University Hospital in Middlesbrough, U.K.

"Based on our findings in 29 patients over 6 months, we will advise NICE that a fully powered nationwide study is feasible under the U.K. definition of refractory angina."

He co-authored the presentation with Professor of Health Services Research Rod Taylor, Ph.D. from the University of Exeter Medical School; Dr. Simon Thomson from Basildon, U.K., and Professor Jon Raphael and Morag Brookes, RGN, BSc, MSc, of the Department of Anaesthesia and Pain Management, South Tees Hospitals NHS Foundation Trust, Middlesbrough, U.K.

Although the study was not formally powered to investigate within- or between-group treatment differences, "compared to baseline, there were trends across a number of the outcomes, including exercise capacity and health-related quality of life, of larger improvements in the SCS compared to usual care group at 3 and 6 months," Brookes said. She is presenting the findings in a poster today at the International Neuromodulation Society 12th World Congress.

In the study, 29 patients at four centers were randomly assigned to either receive SCS and usual care (15 patients) or usual care alone (14 patients). The patients were assessed at 3 and 6 months. All outcome measures showed an improvement in the SCS group. These included an increase in exercise capacity and decrease in angina attack frequency.

"We found SCS therapy and trial outcome measures to be acceptable and appropriate for future randomized controlled trials," Brookes added. "All patients completed the study, showing that study burden was feasible. In addition, SCS appeared to be a safe therapy. There were no device-related serious adverse events over the 6-month follow-up period."

The clinical trial was approved for up to 45 patients and received ethics panel clearance in 2011. However, enrollment was hampered in part by basing the inclusion criteria on the European Cardiology Society definition of refractory angina. Unlike the U.K. version, this definition only addresses if revascularization is unfeasible, and not whether the risks of revascularization surgery may be unjustified.

Spinal cord stimulation has been used in refractory chronic angina pectoris in Europe since the 1980s. In 2009, the prevalence of the intervention for this condition ranged from Sweden to, in decreasing order, Italy, Germany, and Denmark, according to cardiologist Siegfried Eckert, MD, of the Heart and Diabetes Center North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany.

He is presenting an oral abstract at the 12th World Congress today on 148 patients who received SCS for refractory angina pectoris since 2001. He concludes SCS is a safe symptomatic treatment for this condition that can lower consumption of nitrate medication, and decrease the need for medical consultations and hospital stays.

"Despite these well known symptomatic improvements," he commented about SCS in refractory chronic angina pectoris in Medscape in 2009, "SCS is still not recognized by many cardiologists. Its acceptance in European countries is low and varies." He added that independent, systematic investigations are needed.