Each year, approximately 795,000 people experience a new or recurrent stroke1 in the United States, and approximately a half million people in Western Europe are similarly afflicted2. Today, Medtronic, Inc. announces two significant clinical trials related to medical device interventions for stroke. First enrollments in the global CRYSTAL AF (Study of Continuous Cardiac Monitoring to Assess Atrial Fibrillation After Cryptogenic Stroke) trial have taken place. The trial will use the Reveal® XT Insertable Cardiac Monitor (ICM) to assess the incidence of atrial fibrillation (AF) in patients with cryptogenic stroke (stroke of an undetermined cause) or transient ischemic attack (TIA) in order to aid physicians in determining the optimal course of treatment for these patients. It is widely recognized that patients with sustained AF are at increased risk of stroke3.
A second trial, called SISTERS (Spasticity In Stroke – Randomized Study), is being initiated at centers in Europe and the United States to compare the effectiveness of Intrathecal Baclofen (ITB) Therapy to best medical therapy in managing generalized, severe, post-stroke spasticity (tightening of the muscles). This clinical trial is designed to add to the body of clinical evidence for ITB Therapy, which is FDA-approved for the treatment of post-stroke spasticity.
“The clinical trials announced today showcase Medtronic’s wide and deep expertise and our commitment to the management of those who have suffered a stroke by reducing its spasticity consequences and maximizing preventive therapy for future strokes,” said Rick Kuntz, M.D., president of the Neuromodulation business and senior vice president at Medtronic. “Stroke is a chronic disease that affects a large population of patients and these two studies seek to provide a higher level of clinical evidence for important medical device interventions that can aid in the diagnosis of stroke as well as the management of intractable spasticity, which is a common outcome of stroke.”
About AF, Stroke and the CRYSTAL AF Trial
Stroke can be the result of intracerebral or subarachnoid hemorrhage or more commonly, from a blood clot embolism causing acute blockage of a major brain vessel, a so-called ischemic stroke (lack of blood supply to the brain). In many cases, a cause for the ischemic stroke is identified, but in more than one-fourth of cases, the cause remains unexplained. AF is one of the most common irregular heart rhythms, affecting up to seven million people worldwide; it is known that AF is an independent risk factor for stroke, increasing risk about five-fold3. The American and European stroke guidelines4,5 recommend a change in medication from antiplatelet drugs to oral anticoagulants when a stroke patient is found to have AF.
CRYSTAL AF will involve approximately 450 cryptogenic stroke or TIA patients without a prior history of AF, at 45 centers in Europe, Canada and the United States. The primary objective is to evaluate the time to first documented event of AF following cryptogenic stroke or TIA through six months’ continuous heart rhythm monitoring using the Medtronic Reveal XT insertable cardiac monitor (Continuous Monitoring arm) and Medtronic CareLink® Network, compared to standard of care optimal medical treatment (Control arm). Patients will be followed at one, six and 12 months, and every six months thereafter; results are expected in 2012.
“Detection of AF in cryptogenic stroke patients is of paramount importance with respect to the optimal medical therapy to reduce the risk for a stroke recurrence. Continuous monitoring with the Reveal XT is a new and very promising approach for this purpose,” said Prof. Dr. Med. J. Brachmann, a cardiologist at Klinikum Coburg in Coburg, Germany. The first enrollment in CRYSTAL AF recently took place at Klinikum Coburg under Prof. Brachmann.
About the Reveal XT Insertable Cardiac Monitor
Placed just under the skin of the chest area in a short outpatient procedure, the Reveal XT device provides up to three years of continuous heart rhythm monitoring. Reveal XT captures and stores an electrocardiogram (ECG) automatically, according to physician-programmed settings. Later, a physician analyzes the stored information which can be transmitted remotely via the Medtronic CareLink® Network, or viewed during an in-office patient visit. Clinical data available to the physician includes views of individually stored ECG episodes, or longer-term trended diagnostic data via Reveal XT’s Cardiac Compass® Report, including daily AF burden, patient activity, and average day and night heart rates.
About the SISTERS Trial, ITB Therapy and Spasticity Due to Stroke
SISTERS will involve approximately 88 patients at 20 centers in Europe and the United States. The study is a randomized, controlled, multi-center study to compare the effect of ITB Therapy on generalized, severe spasticity in post-stroke patients. The primary objective is to evaluate the effectiveness of ITB Therapy in reducing spasticity compared to best medical therapy in adult post-stroke patients. Other outcomes to be addressed in the study include function, quality of life and cost-effectiveness.
Spasticity is caused by damage or injury to the part of the central nervous system (the brain or spinal cord) that controls voluntary movement. This damage disrupts important signals between the nervous system and muscles, creating an imbalance that increases muscle activity or spasms. Spasticity can make movement, posture, and balance difficult. In severe cases, spasticity impacts daily activities, sleep patterns, and care giving. In studies, people have reported that ITB Therapy helped them be more independent, allowing them to feed or dress themselves, sit more comfortably, or transfer more easily. Caregivers also reported that care is easier with ITB Therapy.
ITB Therapy uses a surgically implanted programmable pump and catheter that delivers medication which helps relieve severe spasticity. This medication is a liquid form of baclofen that goes directly into the intrathecal space where cerebral spinal fluid flows around the spinal cord. By administering the medication directly into the spinal fluid, ITB Therapy decreases spasticity with fewer possible side effects than what is often seen with higher doses of oral medications.
- Heart Disease and Stroke Statistics 2009 Update: A Report From the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation 2009;119;e32-e181
- European Stroke Organisation Web site. http://www.eso-stroke.org/faq_02.php?cid=8
- Stroke: 1991; 22:983-988
- Adams HP Jr, et al. Circulation 2007. May 22;115(20):e478-534. Erratum in Circulation 2007. Oct 30;116(18):e515
- The European Stroke Organisation (ESO) Executive Committee and the ESO Writing Committee. Guidelines for Management of Ischaemic Stroke and Transient Ischaemic Attack 2008. Cerebrovasc Dis. 2008;25(5):457-507