Treatment strategy based on the natural course of the disease for patients with spontaneous isolated abdominal aortic dissection

Acute Symptomatic Isolated Abdominal Aortic Dissection - Clinical Characteristics, Outcome, and Sex Differences

BACKGROUND

Acute isolated abdominal aortic dissection (IAAD) is a rare condition and treatment recommendations are lacking. Most previous studies included both symptomatic and asymptomatic patients. The aims were to determine the proportion of IAAD among patients with acute type B aortic dissection as well as to describe patient characteristics, radiological findings, and frequency of early and late complications and to explore sex differences.

METHODS

This was a retrospective cohort study including all patients hospitalized with acute symptomatic IAAD in Stockholm County during 2012-2021.

RESULTS

A total of 277 patients with acute type B aortic dissection were identified, of whom 10% (n = 28/277) had acute IAAD. Median age was 56 years and 43% (n = 12/28) were women. Hypertension was diagnosed in 46% (n = 13/28) prior to admission. At onset, abdominal pain was the predominant complaint (93%, n = 26/28) and 93% (n = 26/28) were hypertensive on admission. The suprarenal aorta was involved in 39% (n = 11/28) and at least 1 of the iliac arteries in 50% (n = 14/28). All but 1 patient had uncomplicated IAAD (96%, n = 27/28). One patient presented with aortic rupture, treated with open surgical repair. Among patients with primarily uncomplicated IAAD, 7% eventually developed chronic complications (n = 2/27). Median maximum aortic diameter at 1-year follow-up was 21 mm (interquartile range 17-28). Only 1 patient had an aortic diameter exceeding 30 mm. None of the patients died during follow-up; median follow-up was 3.0 years (interquartile range 2-8).

CONCLUSIONS

Early and late complications are rare in patients with acute symptomatic IAAD and a conservative approach with antihypertensive treatment and surveillance in uncomplicated cases seems reasonable.

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.

Complicated and Uncomplicated Isolated Abdominal Aortic Dissections Demonstrate Different Patient Characteristics and Outcomes

BACKGROUND

Isolated abdominal aortic dissection (IAAD) is a rare entity with poorly defined risk factors and wide variation in management. We set forth to compare patient characteristics, management, and outcomes of uncomplicated isolated abdominal aortic dissection (uIAAD) versus high risk and complicated isolated abdominal aortic dissection (hrcIAAD) to investigate whether these categories can be utilized to guide IAAD management and provide risk stratification for intervention.

METHODS

Retrospective chart review was performed to identify all patients with spontaneous IAAD at a tertiary health care system between 1996 and 2022. Demographics, comorbidities, factors relating to initial presentation including imaging findings, and dissection outcomes including long-term all-cause mortality and aortic-related mortality from time of dissection to final available record were abstracted. IAAD demonstrating rupture or malperfusion were designated as complicated, those with aortic diameter greater than 4 cm on presentation or refractory pain were designated as high risk, and the remainder was designated as uIAAD. All variables were compared between hrcIAAD and uIAAD using Fisher's exact test, unpaired t-test, and Mann-Whitney U-test as appropriate.

RESULTS

Over the study period, 74 patients presented with spontaneous IAAD (mean age 60 ± 16 years, 61% male) with postdissection follow-up records to an average of 6.8 ± 5.8 years. Of these, 76% presented with uIAAD versus 24% with hrcIAAD. hrcIAAD was diagnosed at a significantly younger age on average than uIAAD (52 ± 14 vs. 62 ± 16 years, P = 0.02), was less likely to present with concomitant hyperlipidemia (0% vs. 41%, P < 0.01), coronary artery disease (6% vs. 47%, P < 0.01), and prior smoking history (39% vs. 72%). hrcIAAD was more likely to present in patients with a genetic aortopathy (27% vs. 7%, P = 0.03). Hypertension was not significantly different between groups. Patients with hrcIAAD were significantly more likely to present with extension into iliac arteries compared to uIAAD (61% vs. 18%, P < 0.01). A much higher proportion of hrcIAAD required hospitalization compared to uIAAD (83% vs. 30%, P < 0.01) and operative intervention (67% vs. 7%, P < 0.01). While there was no significant difference in all-cause mortality between groups, there was a significant difference between aortic-related mortality which only occurred in those with hrcIAAD (28% vs. 0%, P < 0.01).

CONCLUSIONS

Comparison of long-term outcomes suggests that hrcIAAD is associated with increased hospitalization and need for operative intervention compared to uIAAD. Significant differences in atherosclerotic risk factors and proportions of connective tissue disease history between patients who present with hrcIAAD and uIAAD suggest that differences in underlying etiology are largely responsible for whether IAAD progresses towards rupture or has a more benign course and should be considered in risk stratification to guide more specific and targeted management of IAAD.

Clinical characteristics and therapeutic strategy for patients with spontaneous isolated abdominal aortic dissection

Objective

Spontaneous isolated abdominal aortic dissection (SIAAD) is a rare aortic emergency and not yet fully understood. This study aims to report the characteristics and treatments of 31 patients with SIAAD in the past 12 years.

Methods

A total of 31 consecutive patients with SIAAD between 2010 and 2022 were included. The clinical manifestations, treatment strategies, and outcomes were reviewed. Following the SVS/STS reporting standard, we compared the clinical characteristics with different locations of primary entry, or different numbers of dissected zones. Furthermore, we compared the effects of surgical and conservative therapies on the outcome during the follow-up.

Results

Among the 31 patients with SIAAD, 16 (51.6%) were in the acute phase on admission. The primary entry of SIAAD was mainly located in Zone 9 (67.7%). Most patient presented with dissection involving 1 or 2 aortic zones (61.3%). In addition, 35.5% and 64.5% of SIAADs involved the visceral and iliac arteries, respectively. Compared with asymptomatic SIAADs, the symptomatic ones had longer dissection lengths (P = 0.008) and tended to involve iliac artery more frequently (P = 0.098). There were differences in the number of dissected aortic zones (P = 0.005) among patients with primary entry located in Zone 5 (Supraceliac aorta), Zone 6-8 (Paravisceral aorta) and Zone 9 (Infrarenal aorta). The involvement of visceral artery (P = 0.039) and iliac artery (P = 0.006) was significantly different between the subgroups of SIAAD involving one, two, and three or more aortic zones. The cumulative incidence of adverse false lumen progression events was significantly lower (P = 0.000) and the rate of false lumen thrombogenesis or disappearance was higher in patients receiving surgery (P = 0.001). The cumulative all-cause mortality was 9.7% at 1-year, and 19.7% at 5-year, with no significant difference between surgical and conservative therapies.

Conclusions

Clinical features of SIAAD vary depending on the location of the primary entry and the number of dissected aortic zones. Although surgery was not associated with a lower all-cause mortality compared with conservative therapy, it was associated with a lower incidence of adverse false lumen progression and a higher rate of aortic remodeling.

Optimal medical treatment versus endovascular aortic repair in uncomplicated isolated abdominal aortic dissection

OBJECTIVE

To report the results of optimal medical treatment (OMT) and endovascular aortic repair (EVAR) in patients with uncomplicated isolated abdominal aortic dissection (IAAD).

METHODS

A retrospective review of 96 consecutive patients with uncomplicated IAAD (uIAAD) managed at a single tertiary vascular unit between January 2011 and July 2021 was conducted. Standard methods for univariate and survival analyses were used. The primary outcomes were all-cause mortality. Secondary end points included uIAAD progression, interventional complications, and follow-up aortic intervention.

RESULTS

Initially, 53.1% of patients (51/96) were managed with OMT. No in-hospital deaths occurred. During follow-up, three patients died, and three and two patients who were initially managed with OMT subsequently required endovascular treatment and surgical management, respectively. Initially, 46.9% of patients (45/96) underwent EVAR. One patient died during hospital admission; nine patients had an endoleak after operation and one needed reintervention. Furthermore, during follow-up, five patients died; four patients needed reoperation, one surgery and three endovascular treatments. The overall long-term mortality was 8.4%, and follow-up aortic intervention rate was 9.5% (median follow-up, 54 months; interquartile range, 33-81 months) with no significant difference between groups. Of note, 12 patients (12.6%) suffered uIAAD progression, which was higher in the OMT group than EVAR group (10 [19.6%] vs 2 [4.5%]; P = .03).

CONCLUSIONS

uIAAD may be managed safely by OMT with regular surveillance, despite the risk of disease progression. Compared with OMT, EVAR could significantly prevent uIAAD progression. For anatomically suitable patients with uIAAD progression and who are unresponsive to OMT, pre-emptive EVAR is a safe and feasible option.

Similar Midterm Clinical Outcomes and Aortic Remodeling in Bifurcated and Straight Aortic Stent Grafts Used to Treat Isolated Abdominal Aortic Dissection

PURPOSE

The optimal treatment for isolated abdominal aortic dissection (IAAD) is currently unknown. We compared the effects of straight and bifurcated aortic stent grafts on postoperative aortic remodeling in patients with IAAD.

MATERIALS AND METHODS

From February 2012 to December 2019, 57 patients with IAAD were treated using endovascular methods, including either a bifurcated or a straight aortic stent graft. The clinical features, risk factors, computed tomography angiograms, midterm follow-up results, and aortic remodeling of these patients were reviewed and analyzed.

RESULTS

In total, 44 (77%) patients were treated with a bifurcated graft and 13 (23%) patients were treated with a straight graft. Patients treated with straight grafts had fewer common iliac arteries involved (38% vs 73%, p=0.023), the dissection length was shorter (76.3 ± 40.0 vs 116.2 ± 56.7 mm, p=0.011), and the preoperative aortic diameter (26.0 ± 5.6 vs 35.2 ± 12.1 mm) and the false lumen diameter (13.1 ± 5.2 vs 21.2 ± 11.3 mm) were smaller. During the procedure, there were 3 (5.3%) type I endoleaks, 1 (1.8%) surgical conversion and 1 (1.8%) partial renal artery coverage without perioperative mortality. Patients with straight grafts had shorter operative time (96.5 ± 24.4 vs 144.2 ± 49.0 minutes, p<0.0001). The median follow-up duration was 37.6 ± 21.0 (range = 3-89) months with 1 (1.8%) aortic-related death. Type A aortic dissection occurred in 1 (1.8%) patient. New descending aortic dissection occurred in 3 (5.3%) patients, and 1 patient advanced to type A aortic dissection 3 months later. Two (3.5%) patients had limb occlusion. There was no significant difference in aortic remodeling, survival, and freedom from all adverse events between the 2 treatment strategies.

CONCLUSIONS

Endovascular treatment provides a safe, minimally invasive treatment for IAAD in midterm follow-up. Compression of the true lumen at the aortic bifurcation is the main concern after treatment with a bifurcated graft. Straight grafts are an excellent alternative for some patients, with the benefit of reduced procedural time, effective aortic remodeling, and excellent clinical prognosis. More experience is needed to offer clear recommendations for making treatment decisions as well as determine long-term effectiveness and durability.

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.

Incidence and natural history of isolated abdominal aortic dissection: A population-based assessment from 1995 to 2015

BACKGROUND

Isolated abdominal dissection (IAD) is an uncommon clinical problem that is less well-understood than thoracic aortic dissection (AD). We performed a population-based assessment of the incidence, natural history, and treatment outcomes of IAD to better characterize this disease.

METHODS

We used the Rochester Epidemiology Project to identify all Olmsted County, MN residents with a diagnosis of AD, intramural hematoma or penetrating ulcer (1995-2015). Diagnostic imaging of all patients was reviewed to confirm the diagnosis of IAD for inclusion. Presentation, treatment, and outcomes were reviewed. Survival of IAD patients was compared to age- and sex-matched population controls 3:1.

RESULTS

Of 133 residents with aortic syndrome (AD, intramural hematoma, or penetrating ulcer), 23 were initially diagnosed with IAD. Nine were reclassified as having a penetrating aortic ulcer and were excluded, leaving 14 patients for review (10 male [71%]; mean age, 71 years). Three patients (21%) were symptomatic (abdominal pain, back pain, hypertension) and none had malperfusion or rupture. Prior aortic dilatation was present in eight patients (57%) and Marfan syndrome in one (7%). Two patients (14%) had iatrogenic IAD. Initial management was medical in 13 and endovascular aneurysm repair in one (symptomatic subacute, infrarenal dissection with small aneurysm). The median clinical and imaging follow-up was 6.7 years (range, 0-17 years). An abdominal aortic aneurysm occurred in eight (six at the time of IAD diagnosis, one at 2.9 years, and one at 5.2 years after diagnosis). The average growth in the entire cohort was 0.9 ± 0.4 cm, which translated to an average growth rate of 0.09 cm/year. Subsequent intervention was performed in two patients; for severe aortic stenosis with claudication in one (infrarenal aortic stenting) and increasing aortic size in one (open repair). One patient required reintervention (thrombolysis and stenting for endovascular aneurysm repair limb thrombosis). Survival for IAD at 1, 3, and 5 years was 93%, 85%, and 76%, respectively, compared with population controls at 98%, 85%, and 71%, respectively (long rank P = .38). Mortality was due to cardiovascular causes in three patients (21%) and no deaths were aortic related. Major adverse cardiac events occurred in five patients (36%) owing to heart failure.

CONCLUSIONS

IAD is rare. The initial management for asymptomatic patients is medical. The aortic growth rate is slow, with no aortic-related mortality and a low rate of aortic intervention. The overall mortality is similar to population controls. Heart failure and cardiac-related death are prevalent, suggesting that close cardiovascular care is needed in this patient population.

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.

Contemporary Results of Endovascular Repair of Isolated Abdominal Aortic Dissection with Unibody Bifurcated Stent Grafts

OBJECTIVES

To report the midterm safety and efficacy of the Aegis™-B (Microport, Shanghai, China) unibody bifurcated stent graft for endovascular treatment of isolated abdominal aortic dissection (IAAD).

BACKGROUND

Isolated abdominal aorta dissection (IAAD) is a rare event. Endovascular stent grafts seem to offer an efficient therapeutic approach to treat IAAD. However, the relatively small diameter of the infrarenal aorta and aortic bifurcation remains the main anatomical limitation to endovascular repair.

METHODS

Between 2008 and 2015, we retrospectively evaluated 32 IAAD patients (21 men; mean age 58 ± 18 years), who underwent endovascular repair using Aegis™-B unibody bifurcated stent graft. Narrow proximal landing zone and narrow distal aorta was present in 11 (34.4%) patients and 10 (31.3%) patients, respectively. In the follow-up period, aortic remodeling was observed with computed tomography angiography.

RESULTS

All patients were treated by endovascular means, with a primary technical success rate of 100%. During a mean follow-up period of 30.71 ± 16.36 months (range, 8-56 months), no death, rupture, stent fracture, material failure, or device migration was observed. Complete false lumen thrombosis was observed in all patients at 1 year, and all patients were free from false lumen growth in the follow-up.

CONCLUSIONS

Endovascular treatment of IAAD using the Aegis™-B system appears to be safe and effective. Results from this study suggest this algorithm can provide stable, secure fixation for IAAD patients with narrow proximal landing zone, and distal aorta.