Article: Parish, et al. “Aortic size in acute type A dissection: implications for preventive ascending aortic replacement.” European Journal of Cardio-thoracic Surgery 35 (2009) 941—946.
Idea: Elective replacement of the ascending aorta is recommended to prevent type A aortic dissection when any section of the proximal arch measures >5.5 cm. Little data exists showing how the aorta of patients with type A aortic dissections truly measure; this study sought to characterize aortic diameter of patients presenting with type A dissections.
Study: Retrospective study examining TEE performed in conjunction with surgical intervention for acute type A aortic dissection “over a recent 10-year period” (study published in 2008); total 177 patients included. Age, gender, BSA also recorded. Pre-repair TEE images obtained under general anesthesia and analyzed by a single technician – aortic diameters measured at: AV annulus, sinus segment, sinotubular junction, ascending aorta; the largest measurement was recorded as max aortic diameter. Predicted aortic diameters were calculated based on age, gender, BSA for each aortic position.
Inclusion: TEE performed in conjunction with operative repair for acute type A aortic dissection.
Exclusion: Known/suspected Marfan, bicuspid AV, hx of previous cardiac surgery, patients with poor quality TEE precluding quantitative analysis, patients found/suspected to have chronic/subacute dissections
Results: 177 patients: 60F, 117M. The average max aortic diameter at any location at time of dissection was 5.3 +/- 1.0 cm. Max diameter in sinus segment in 9.6%, ascending aorta in 87.6%. 5 patients had equal dilatation of ascending aorta, sinotubular junction, and sinus segment. • Range of measured aortic diameters: Annulus: 1.6-4.1 cm Sinus segment: 2.7-6.2 cm Sinotubular junction: 2.2-6.1 cm Ascending aorta: 2.8-8.7 cm
Important finding: 62% of patients had maximum aortic diameters less than 5.5 cm at time of dissection, 42% had max diameters less than 5.0 cm. Over 20% had max aortic dimensions less than 4.5 cm. In women 12% had max dimension less than 4.0 cm.
Takeaway: Current recommendations still list elective replacement for ascending aortic aneurysm at an aortic diameter of 5.5 cm. In this study >60% of patients with acute type A aortic dissection presented with diameters <5.5 cm; current surgical guidelines would fail to prevent the majority of acute dissections seen in this cohort. This study examined aortic size at time of surgery, after dissection had occurred; it is generally believed that the aortic size prior to dissection would be smaller than that after dissection has occurred, so potentially an even greater number dissections would have failed to have been prevented under current surgical guidelines. It is noted that even though measured diameters were smaller than outlined by guidelines for elective repair, the vast majority of patients had max diameters larger than expected for age/size/gender matched normal patients.
Major points: Ascending aortic size is not a sufficient marker of risk for acute type A dissection. Ascending aortas between 4-5 cm (especially in women) are highly abnormal and potentially dangerous repair should be considered. Medical management for aneurysms >4 cm should be aggressive especially treatment of HTN
Post by Issac Wegner, MS4