Results could change treatment guidelines
Current guidelines recommend beta-blockers in Marfan syndrome prior to a dilatation size of 4.5 to 5 cm when surgery is indicated, according to Dr. Pitcher, but he said these data might change guidelines. While reinforcing the benefit of beta-blockers, this analysis suggests ARBs should also be considered, possibly in combination with beta-blockers.
“What I hope this meta-analysis does is add substantially to the certainty with which physicians can discuss treatments with patients.”
As for the mechanism, it is reasonable to speculate the antihypertensive effect of both medications is relevant, but each has plausible independent activities that might contribute to modifying aortic growth, according to Roland R.J. van Kimmenade, MD, PhD, a specialist in aortic diseases and heart failure at Raboud University Medical Center, Nijmegan, the Netherlands.
Citing several studies, he suggested that the benefit of beta-blockers could also stem from their ability to reduce heart rate and aortic stiffness while ARBs are likely to inhibit the interaction between the renin-angiotensin system (RAS) and TGF-beta pathway. Each of these might participate in risk of aortic root growth, according to Dr. van Kimmenade, who was invited by ESC to discuss this study.
On the basis of these data as well as past studies, he agreed that the combination of beta-blockers and ARBs might not just be additive but “even a little bit synergistic.”
While Dr. Pitcher suggested that the evidence supports starting both beta-blockers and ARBs soon after the diagnosis, Dr. van Kimmenade said, “I don’t like using beta-blockers in young patients, but ARBs are now shown to be an excellent alternative.”
Ultimately, “the prescription pencil will not replace the surgical knife” in a disease that is likely to eventually require surgery to prevent life-threatening events, according to Dr. van Kimmenade, but he agreed that these data provide more certainty about the value of beta-blockers and ARBs for slowing progression.
Dr. Pitcher reports no potential conflicts of interest. Dr. van Kimmenade has financial relationships with Bayer and Novartis.