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Clinical Trial Results and Recommendations
Following on from a clinical trial in the USA on the use of the beta blocker Atenolol and angiotensinreceptor blocker (ARB) Losartan in slowing down aortic growth, The Marfan Foundation have released the following guidelines.
Medications can help treat many types of problems with the heart and blood vessels. It isrecommended that either a beta blocker or angiotensin receptor blocker (ARB) be started at the time of diagnosis of Marfan syndrome with the goal of reducing the rate aortic root enlargement. Doses suggested are those given in the 2014 Atenolol vs. Losartan randomized trial.
• Atenolol should be increased to a maximum dose of 4 mg/kg/day (not to exceed 250 mg/day)with a goal of a 20% or greater decrease in average heart rate measured on a 24-hr recording. This high dose of atenolol is generally well tolerated.
• Alternatively, in patients who cannot tolerate beta blockers, angiotension receptor blockers (ARBs) such as losartan, provide a similar amount of protection against aortic enlargement. Losartan should be started at an initial dose of 0.4 mg/kg/day and increased based on weightto a maximum dose up to 1.4 mg/kg/day, not to exceed 100 mg.
• Since the trial data provides evidence that in younger patients both drugs are associated with a greater decrease in aortic-root z-score over time, beta blockers or angiotension receptor blockers should be prescribed at the time of diagnosis even in the youngest children. Therefore, it isrecommended that once a diagnosis is made, with or without aortic dilation, medical therapy shouldbe started, maintained and continued after surgery indefinitely.
• Based on the patient’s history, individualized treatment plans must be developed when deciding onwhich medical therapy to use (beta blocker [atenolol] or ARB [losartan]). However, since the trial only investigated use of either atenolol or losartan, that is the only hard evidence- based recommendation that can made at this time. There are other trials ongoing which may provide additional information about combination therapy with both ARB drug and beta blocker
• There has been a small study of ACE-inhibitor therapy in Marfan syndrome; more information is needed before recommending the use of this class of agents for the prevention of aortic disease in Marfan syndrome.
Credit: The Marfan Foundation (www.marfan.org)