Aortic Dissection Limited to Abdominal Aorta: an Underrecognized Entity?

Isolated Abdominal Aortic Dissection With and Without Abdominal Aortic Aneurysm

OBJECTIVE

The aim of this study was to report the clinical presentation and treatment outcomes of patients treated for IAAD with and without abdominal aortic aneurysm (AAA) in a single academic institution in South America.

MATERIALS AND METHODS

A retrospective review of all patients with IAAD with or without concomitant AAA between January 2002 and December 2023 from a single academic hospital was performed.

RESULTS

Eighteen patients with IAAD were diagnosed of whom 13 (72.2%) were males. Median age was 63 years (range: 43-88 years). Sixteen (88.8%) patients presented with symptoms, and in two (11.1%) asymptomatic patients IAAD was an incidental finding. Ten (55.5%) patients had concomitant abdominal aortic aneurysm (AAA), with a median size of the aneurysm of 49.5 mm (range: 44-66 mm). No statistical differences in baseline characteristics were seen between patients with concomitant IAAD and AAA and patients with only IAAD. Seven (38.8%) patients presented chronic dissection, and 11 (61.1%) patients had acute dissection. Five (27.7%) patients were treated conservatively with blood pressure, pain control, and antiplatelets; endovascular surgery was performed in eight (44.4%) patients and open surgery in five (27.7%) patients. The complication rate was 22.2% (n = 4), and the mortality rate was 0%. Median follow-up was 36 months (range: 6-240 months). Complete remodeling was seen in all patients except two patients who underwent conservative treatment. Of those, one had partial remodeling, and the other no changed.

CONCLUSION

Isolated aortic dissection of the abdominal aorta is an uncommon condition, with acceptable different treatment strategies, from conservative to invasive treatments. Sometimes IAAD can concur with AAA, and when so, invasive treatment might be considered. More studies describing the natural history of AAA and its association with IAAD are warranted, as well as further research reporting long-term outcomes on aortic remodeling after different treatment modalities.

Open Surgical Treatment of Acute Spontaneous Isolated Abdominal Aortic Dissection

BACKGROUND

The aim of this paper is to report our single-center experience in the open surgical treatment of acute spontaneous infrarenal isolated abdominal aortic dissection (siIAAD).

METHODS

This was a single center retrospective study. Between January 2015 and 2020 ten patients were treated due to acute siIAAD with open surgery. There were no patients treated for chronic siIAAD in this time period. Patients who had concomitant thoracic aortic involvement were excluded from this report.

RESULTS

The group consisted of 7 male and 3 female patients. History of hypertension was present in nine patients and six were active smokers. The abdominal/back pain was described in 9 patients, two had acute limb ischemia and three had aortic rupture. Median dissection length was 91 mm (65.7 - 106), median distance from the lowest renal artery was 30 mm (20.7 - 49.3) and median abdominal aortic diameter was 58.5 mm (32.5 - 66.2). Supracoeliac clamp was used in three cases with a ruptured aorta and suprarenal in two patients. The mean duration of proximal clamping time was 24.3 ± 7.49 min. One patient died of postoperative acute myocardial infarction, one suffered nonfatal pulmonary embolism and one had deep venous thrombosis. No aortic-related deaths and/or reinterventions occurred during the median follow-up of 32 months.

CONCLUSIONS

Acute siIAAD is a rare event which affects mostly male smokers with hypertension. Open surgery is a technically demanding procedure with acceptable complication rates and should be performed in specialized high-volume centers for the treatment of aortic disease. Future efforts to establish a multicenter registry to evaluate the prevalence of the disease and treatment options could provide better and more comprehensive guidelines for the treatment of acute siIAAAD.

A systematic review and meta-analysis of isolated abdominal aortic dissection

OBJECTIVE

Isolated abdominal aortic dissection (IAAD) has remained poorly understood because of its rarity. We explored the prevalence, clinical characteristics, risk factors, imaging characteristics, and treatment strategy of IAAD to facilitate its diagnosis and treatment.

METHODS

We performed a meta-analysis of 17 studies, with single-arm-based and network meta-analysis as the main data synthesis method. The Medline, Embase, and Cochrane library were searched from their inception to July 2018. A total of 9163 patients with aortic disease were enrolled, with IAAD identified in 491 patients.

RESULTS

The pooled prevalence of IAAD among cases of aortic dissection overall, type B aortic dissection, and type A aortic dissection was 1.7% (95% confidence interval [CI], 0.9%-3.4%), 4.1% (95% CI, 2.5%-6.6%), and 2.0% (95% CI, 0.7%-3.9%), respectively. Abdominal pain was the most common symptom (50.8%), followed by back pain (30.5%), and chest pain (21.7%). Up to 41.0% of the patients with IAAD did not present with any clinical symptoms, and up to 71.0% of these patients had negative findings on physical examination. The top three most prevalent risk factors for IAAD were hypertension, hyperlipidemia, and smoking. Most cases of IAAD were limited to the aorta inferior to the renal arteries (81.7%), and the average aortic diameter was 4 cm. No statistically significant difference was observed between open surgery, endovascular aortic repair, and conservative management for both early and late mortality.

CONCLUSIONS

The results from the present meta-analysis regarding IAAD support the following conclusions and recommendations. First, IAAD is rare and predominantly affects males. Second, symptoms (pain) might or might not be present, and physical findings will rarely be found on abdominal examination. Third, hypertension is the most prevalent risk factor. Fourth, most cases IAAD will be infrarenal. Finally, a complication-specific approach, similar to that for type B aortic dissection, would be appropriate.

Endovascular treatment of spontaneous isolated abdominal aortic dissection

Isolated abdominal aortic dissection is a rare clinical disease representing only 1.3% of all dissections. There are a few case series reported in the literature. The causes of this pathology can be spontaneous, iatrogenic, or traumatic. Most patients are asymptomatic and symptoms are usually abdominal or back pain, while claudication and lower limb ischemia are rare. Surgical and endovascular treatment are two valid options with acceptable results. We herein describe nine cases of symptomatic spontaneous isolated abdominal aortic dissection, out of which four successfully were treated with an endovascular approach between July 2003 and July 2013. All patients were men, smokers, symptomatic (either abdominal or back pain or lower limb ischemia), with a history of high blood pressure, with a medical history negative for concomitant aneurysmatic dilatation or previous endovascular intervention. Diagnosis of isolated abdominal aortic dissection were established by contrast-enhanced computed tomography angiography (CTA) of the thoracic and abdominal aorta. All nine patients initially underwent medical treatment. In four symptomatic cases, non-responsive to medical therapy, bare-metal stents or stent grafts were successfully positioned. All patients completed a CTA follow-up of at least 12 months, during which they remained symptom-free. Endovascular management of this condition is associated with a high rate of technical success and a low mortality; therefore, it can be considered the treatment of choice when it is feasible.