The Risk for Type B Aortic Dissection in Marfan Syndrome | Journal Scan
What are the clinical predictors of type B aortic dissection in patients with Marfan syndrome?
This study evaluated 600 patients with Marfan syndrome and magnetic resonance imaging or computed tomography imaging of the aorta followed at one of four centers for a median of 6 years. The study examined variables associated with type B aortic dissection or a combined endpoint of type B aortic dissection, distal aortic surgery, or death.
Mean age was 36 ± 14 years and 52% were male. During follow-up, type A and type B aortic dissections occurred in 2 and 54 patients, respectively. Variables independently associated with type B aortic dissection included prior aortic surgery (hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.2-3.8; p = 0.01) and a proximal descending aorta ≥27 mm in diameter (HR, 2.2; 95% CI, 1.1-4.3; p = 0.02). On multivariable analysis, aortic distensibility and the presence of an aortic hump were not associated with type B aortic dissection. The use of angiotensin-II receptor blockers was associated with fewer type B aortic dissections (HR, 0.3; 95% CI, 0.1-0.9; p = 0.03).
The authors concluded that type B aortic dissection is not uncommon in those with Marfan syndrome. Prior prophylactic aortic surgery or a dilated proximal descending aorta is associated with increased risk of type B dissection in these patients.
This study has several important findings. While 37% of patients had prophylactic ascending aortic repair during follow-up, only two patients (0.3%) experienced type A aortic dissection, which suggests that current clinical practice may be effective. This cohort experienced a much larger rate of type B aortic dissection (1.5% per year), with both prior aortic surgery and the presence of a dilated proximal descending aorta independently associated with increased risk of these events. While these variables may be helpful to identify those at greater risk, each of these variables was present in about half of patients with subsequent type B dissection, and many of these patients had neither or only one of these risk factors. How to apply these findings is not clear, as the role of prophylactic interventions to the descending aorta is not established. Finally, this study suggests that the use of angiotension-II receptor blockers may be associated with fewer type B dissections, although recent literature emphasizes the need for caution in interpreting treatment effects without randomized studies.
Keywords: Marfan Syndrome, Aneurysm, Dissecting, Angiotensin II Type 2 Receptor Blockers, Aorta, Risk, Magnetic Resonance Imaging, Tomography, X-Ray Computed
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