MAPS results positive for coiling aneurysms


The largest randomised, controlled study on the clinical effectiveness of coils establishes the procedure as a safe and effective treatment for ruptured and unruptured aneurysms. In the trial, 96% of patients with unruptured aneurysms and 90% of patients with acutely ruptured aneurysms were alive and free of disability out to 15 months after treatment. The results of the MAPS (Matrix and platinum science) trial were announced during the Society of NeuroInterventional Surgery (SNIS) 8th Annual Meeting in Colorado Springs, USA.

The results establish a new standard for the measurement of aneurysm treatment success, target aneurysm recurrence and demonstrate that coiling is an excellent treatment for both ruptured and unruptured aneurysms. Target Aneurysm Recurrence (TAR) is defined as clinically relevant recurrence resulting in: target aneurysm re-intervention, rupture/re-rupture and/or neurologic death.


Begun in 2007, the MAPS trial is the largest randomised controlled study on the clinical effectiveness of coils for treating both ruptured and unruptured aneurysms. Designed and led by principal investigators, S Claiborne Johnston, Cameron McDougall, and Anil Gholkar, the trial examined 626 patients worldwide with a single aneurysm, 4–20mm in size, treated with Matrix2 detachable coils or GDC detachable coils.


In the trial, 96% of patients with unruptured aneurysms and 90% of patients with acutely ruptured aneurysms were alive and free of disability out to 15 months after treatment. Trial results also demonstrate that, overall, Matrix2 Detachable Coils are as effective as GDC Detachable Coils (target aneurysm re-intervention rates of 13.3% vs. 14.6%, respectively). In aneurysms with good occlusion immediately post procedure Matrix2 Detachable Coils demonstrate a statistically significant, superior long-term target aneurysm re-intervention rate of 2.7% compared to GDC Detachable Coils (9.6%).


“The MAPS Trial shows that the field of neurointervention is now mature enough to successfully carry out a randomised, prospective trial that is rigorously overseen, assesses the performance of contemporary technology and is applicable worldwide,” said Cameron McDougall, the current president of SNIS.


Implanted in more than 250,000 patients worldwide, GDC detachable coils are made of very soft platinum wire and were the first coils cleared by the FDA for the minimally invasive treatment of brain aneurysms in 1995. Approved in 2002, Matrix2 Detachable Coils incorporate a PGLA polymer on the outside of a traditional platinum coil that is designed to degrade over time and promote rapid tissue development within the aneurysm.


 “While the neurovascular specialty commonly measures aneurysm treatment success with angiographic images, we believe success should be more closely aligned with patients’ clinical outcomes,” said Mark Paul, president of Stryker Neurovascular. “The MAPS Trial demonstrates the validity of target aneurysm recurrence rate as a clinical endpoint and proves aneurysm coiling is a very effective therapy with excellent clinical outcomes.”


“While not comparing clipping to coiling, the trial shows better endovascular results than previous benchmark studies, specifically ISAT (International subarachnoid aneurysm trial) and ISUIA (International study of unruptured intracranial aneurysms). In addition, the trial’s clinical endpoint has been demonstrated to be clinically relevant and correlate with immediate post-treatment angiogram, making it reliable and easily adopted by future studies to ensure a consistent measure of treatment success.”


“Stryker is very encouraged by the results of the MAPS Trial, and we believe that it has the potential to influence the design of future studies and spur the advancement of new, innovative technologies that can enhance the clinical outcomes of patients with aneurysms in the future,” Mark Paul continued.

Anil Gholkar, principal investigator of MAPS, spoke on the results 


Gholkar spoke to NeuroNews about the results and provided perspective on the results. “An important historical trial surrounding ruptured intracranial aneurysms is the ISAT study of 2002. It examined 2,143 patients with ruptured intracranial aneurysms randomly assigning them to neurosurgical clipping or endovascular coiling. In ISAT, 23.5% of acutely ruptured aneurysm patients assigned to endovascular treatment were dead or disabled at one year. Since then, the majority of ruptured aneurysms have been treated by endovascular coiling. There is less data available on unruptured aneurysms. The most significant study done to date on unruptured aneurysms was the ISUIA study, first published in 1998, which allowed physicians to select coiling as one among a number of possible treatment options and then followed results prospectively. In that trial, approximately 10% of coiled patients were dead or disabled at one year post procedure,” he said.


Could you explain the clinical results in depth?


“Matrix2 Coils include an additional bioactive polymer wound around the outside of the platinum core, a polylactic/polyglycolic combination similar to that used in absorbable sutures. In animal studies, the polymer reduced aneurysm recanalisation/recurrence by creating a more stable occlusion of the aneurysm than that seen when bare platinum coils were used.


For the study, we recruited 626 patients at 43 investigational sites; 26 in the United States and 17 international sites. At one year post-procedure, 96% of patients with unruptured aneurysms and 90% of patient with acutely ruptured aneurysms were alive and free of major disability up to 15 months after treatment. That represents a significant improvement in patient outcomes in the decade since ISAT was published.

The MAPS trial is the largest, most rigorous randomised controlled study to-date on the clinical effectiveness of coils for treating both ruptured and unruptured aneurysms. It establishes a new and higher benchmark for the clinical results against which other, alternative therapies must be measured.”


Why are the results important?


“There is no consensus within the neurovascular specialty about how to measure clinical success in the treatment of intracranial aneurysms. Most recently, physicians have evaluated clinical success based on angiographic images. The MAPS trial was intended to set a new standard for the evaluation of the treatment of aneurysms with coiling, the target aneurysm recurrence, which is more closely aligned with patients’ clinical outcomes. 

This study is important from several points of view. For the first time, we used a clinical endpoint rather than radiological endpoints (i.e. imaging) in a randomised study of this nature. Target aneurysm recurrence is a clinically relevant point which looks at patient outcome as opposed to radiological outcomes which are only surrogate markers. We hope that other researchers will use our endpoint as a basis for similar, meaningful, and definitive outcomes in future studies.


This study also showed better overall clinical outcomes from endovascular treatment of ruptured aneurysms compared to the landmark ISAT study. For a similar patient population, death and disability at one year post procedure were improved from 23% in ISAT to 10% in MAPS. In patients with unruptured aneurysms, the poor outcomes were only seen in 4–5% of patients compared to ~10% in ISUIA. In a randomised study, these are some of the best outcomes we have seen for the treatment of brain aneurysms and it is good news for physicians and patients alike.  


In conclusion, this new clinical endpoint establishes an industry baseline for the evaluation of aneurysm treatment in contemporary practice. The trial will help build consensus within the specialty about how to measure success and should influence the design of future studies and the advancement of new technologies for the treatment of aneurysms.”