Aortic elongation part II: the risk of acute type A aortic dissection

Prophylactic surgery for prevention of acute type A aortic dissection (ATAAD) is reserved for patients with an ascending aortic aneurysm ≥55 mm. Identification of additional risk predictors is warranted since over 70% of patients presenting with ATAAD have a non-dilated aorta or an aneurysm that would not have met the diameter criterion for preventative surgery. Aim of the study was to evaluate ascending aortic elongation as a risk factor for ATAAD and to compare aortic lengths between ATAAD patients and healthy controls.

Aortic lengths and diameters of ATAAD patients were measured on three-dimensional modelled computed tomography and adjusted to predissection dimensions in this cross-sectional single-centre study. Logistic regression was used to evaluate the relation between ATAAD and aortic dimensions. Lengths of different aortic segments were compared with a healthy control group using propensity score matching.

Two-hundred and fifty patients were included in the study (ATAAD, n=40; controls, n=210). Ascending aortic length and diameter proved to be independent predictors for ATAAD (OR=5.3, CI 2.5 to 11.4, p<0.001 and OR=8.6, CI 2.4 to 31.0, p=0.001). Eighty patients were matched based on propensity scores (ATAAD n=40, controls n=40). The ascending aorta was longer and more dilated in ATAAD patients compared with healthy controls (78.6±8.8 mm vs 68.9±7.2 mm, p<0.001, 34.4 mm ±3.2. vs 39.4 mm ±5.7, p<0.001, respectively). No differences were found in lengths of the aortic arch and descending aorta.

Ascending aortic length could serve as an independent predictor for ATAAD. Future studies addressing indications for prophylactic surgery should also investigate aortic length.