Risk of Rupture or Dissection in Descending Thoracic Aortic Aneurysm

Abstract

A neurysm of the descending thoracic (DTA) and thoracoabdominal aorta (TAA) is a life-threatening disorder given the risks of aortic dissection (AD) or rupture and their associated high mortality and morbidity once complications occur. The decision to intervene prophylactically, however, is complicated by the significant mortality and morbidity associated with surgical intervention for these conditions. Current practice guidelines call for surgical repair of asymptomatic thoracic aortic aneurysms with diameters of ≥55 mm as a Class I recommendation. Editorial see p 1600 Clinical Perspective on p 1629Recent observations have shown that adverse aortic events may occur at smaller diameters.2,3 For instance, reports from the International Registry of Acute Aortic Dissection showed that 40% of patients with acute type A AD may have aortic diameter of ≤50 mm, and among those with type B AD, as many as 80% had aortic diameters <55 mm. 3,4 These observations have encouraged re-examination of the current practice guidelines. Furthermore, progression of endovascular technology enables treatment of the aortic diseases less invasively, potentially reducing treatment-related mortality or serious morbidity. 5-9Convergence of these forces suggests that earlier prophylactic interventions for DTAs may be appropriate and emphasizes the need for a deeper understanding of the predictors of these aortic complications. Finally, several aortic measures indexed to body size have been proposed recently as alternatives to simple diameter for predicting complications, 10,11 but few studies have examined the predictive value of these metrics.Unfortunately, there are a number of significant challenges in determining the natural course of unrepaired TAAs, Background-Current practice guidelines recommend surgical repair of large thoracic aortic aneurysms to prevent fatal aortic dissection or rupture, but limited natural history data exist to support clinical criteria for timely intervention. Methods and Results-Of 3247 patients with thoracic aortic aneurysm registered in our institutional Thoracic Aortic Center Database, we identified and reviewed 257 nonsyndromic patients (age, 72.4±10.5 years; 143 female) with descending thoracic or thoracoabdominal aortic aneurysm without a history of aortic dissection in whom surgical intervention was not undertaken. The primary end point was a composite of aortic dissection/rupture and sudden death. Baseline mean maximal aortic diameter was 52.4±10.8 mm, with 103 patients having diameters ≥55 mm. During a median follow-up of 25.1 months (quartiles 1-3, 8.3-56.4 months), definite and possible aortic events occurred in 19 (7.4%) and 31 (12.1%) patients, respectively. On multivariable analyses, maximal aortic diameter at baseline emerged as the only significant predictor of aortic events (hazard ratio=1.12; 95% confidence interval, 1.08-1.15). Estimated rates of definite aortic events within 1 year were 5.5%, 7.2%, and 9.3% for aortic diameters of 50, 55, and 60 mm, respectively. Receiveroperating charact...

Does This Study Make My Aorta Look Fat?

“…Only 16% of this subgroup were free of these events over a median of 14 months. 5 These results are consistent with older studies that led to the current guidelines.…”

“…4 However, advances in anesthesiology, endovascular repair, open surgical repair, and imaging warrant a serious look at the validity of the current guidelines. The observational study by Kim et al 5 in this issue of Circulation is therefore appropriate and worthy of attention. The authors identified patients with descending thoracic/thoracoabdominal aortic aneurysms from a database in their specialty service at their institution.…”

Prevention of Aortic Dissection Suggests a Diameter Shift to a Lower Aortic Size Threshold for Intervention

“…Consequently, expert consensuses and opinions recommend replacement at 60 mm for an open surgical approach and 55 mm for TEVAR, assuming that endovascular treatment enables less operative morbidity and mortality [31,32,33]. Data from the IRAD registry [34] as well as a recent study by Kim et al [35] suggested 59.9-81.6% fail guidelines and dissect at smaller diameters; however, they also evaluated size after the onset of dissection.…”

Surgical Indication for Chronic Aortic Dissection in Descending Thoracic and Thoracoabdominal Aorta

“…Consideration should, therefore, be given to lowering the threshold for intervention, particularly if less invasive endovascular approaches are feasible. 11 However, there are limited natural history data on chronic dissection of the descending aorta and the thoracoabdominal aorta to support clinical criteria for timely intervention. Elefteriades et al 12 suggested that patients with chronic aortic dissection should be treated when the aorta reaches 6 cm in diameter, similar to the value for which treatment is recommended in patients with arteriosclerotic descending thoracic aortic aneurysms.…”