Introduction/purpose The Matrix and Platinum Science Trial (MAPS Trial) was initiated with two objectives. Firstly, this non-inferiority trial was designed to compare results of polymer-modified coils (specifically Matrix2 coils) vs. bare metal coils in the treatment of intracranial aneurysms. Secondly, the trial was intended to examine the correlation between angiographic treatment results and clinical failure. Clinical failure was defined as “Target Aneurysm Recurrence” (TAR). TAR, a composite end point, was said to have occurred if any of the following events were observed:
Target aneurysm rupture after treatment (first or recurrent)
Sudden unexplained death
Target aneurysm retreatment.
While previous randomized trials have compared bare metal coils to polymer-modified coils, none have included follow up beyond 2 years.
Materials and methods Detailsof the Materials and methods have been published previously together with the findings at follow up after one year.1 Briefly, this multicenter trial randomized 626 patients undergoing endovascular treatment for an intracranial aneurysm to either bare metal coils (BMC) or to biopolymer-modified coils (Matrix2). Both ruptured and unruptured aneurysms were included in the trial. Clinical and imaging follow up were obtained one year after treatment, and clinical follow up continued until completion of the study at 5 years. The primary outcome was TAR at 5 years. Imaging outcomes were based upon blinded independent core lab readings.
Results At 5 years TAR was observed in 46 BMC patients and in 44 Matrix2 patients. Ruptures of the target aneurysm occurred after treatment in 3 (1%) BMC and 2 (0.6%) Matrix2 patients. Retreatment without rupture occurred in 42 (13.3%) BMC and 40 (12.9%) Matrix2 patients. Sudden unexplained death occurred in 1 (0.3%) BMC and 2 (0.6%) Matrix2 patients. After 5 years of follow up, TAR was observed in 18/176 (10.2%) patients that originally had immediate post procedure Raymond Grade I angiographic occlusion of their aneurysm. Similarly 11/128 (8.6%) patients that originally had immediate post procedure Raymond II angiographic occlusion experienced TAR, as did 47/184 (25.5%) patients that originally had immediate post procedure Raymond III angiographic occlusion. 3/228 (1.3%) patients with ruptured aneurysms experienced rehemorrhage after coiling during their initial hospitalization. After 5 years of follow up only 2/626 (patients are known to have had target aneurysm rupture following discharge from hospital. Both of these patients had large aneurysms that were unruptured at the time of initial treatment, and both had Raymond III residual aneurysm filling at completion of their treatment. For the MAPS trial the annualized rate of known delayed rehemorrhage after coiling was 2/398/5 = 0.001 (0.1%) per year for unruptured aneurysms and 0 for ruptured aneurysms.
Conclusions While non-inferior to bare metal coils, no benefit to Matrix2 coils was demonstrated. Residual aneurysm filling at the completion of aneurysm treatment (Raymond Score) is predictive of TAR (p < 0.0001). Delayed rupture of coiled aneurysms is uncommon and in this study was observed only inaneurysms with residual filling of the aneurysm dome (Raymond III) after treatment.
McDougall CG, Johnston SC, Gholkar A, et al. Bioactive versus bare platinum coils in the treatment of intracranial aneurysms: the MAPS (Matrix and Platinum Science) trial. AJNR Am J Neuroradiol. 2014;35(5):935–42
Disclosures C. McDougall: 2; C; Microvention, Covidian. S. Johnston: 1; C; Stryker. A. Gholkar: 1; C; Stryker. A. Turk: 1; C; Stryker.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.