A model to demonstrate that endotension is a nonvisualized type I endoleak

Late Type 1A Endoleaks: Associated Factors, Prognosis and Management Strategies

BACKGROUND

Unlike periprocedural Type 1A endoleaks, late appearing proximal endoleaks have been poorly described.

METHODS

We studied all elective EVAR from 2010 -2018 in a single institution. Late endoleaks were defined as those appearing after 1 year. We used Cox regression to study factors associated with late Type 1A endoleaks and survival.

RESULTS

Of 477 EVAR during the study period, 411 (86%) had follow-up imaging, revealing 24 Type 1A endoleaks; 4 early and 20 late. Freedom from Type 1A endoleaks was 99%, 92-81% at 1, 5 and 8 years with a median time to occurrence of 2.5 years (.01-8.2 years). On completion angiogram, only 10% of patients with a late Type 1A had a proximal endoleak, and 60% had no endoleak. Only 21% of late Type 1As were diagnosed on routine 1-year CT angiogram, but 79% had stable or expanding sacs. Two thirds (65%) of the patients eventually diagnosed with late Type 1A endoleaks had previously been treated for other endoleaks, mostly Type 2 (10/13). Age (HR 1.07/year [1.02-1.12], P = 0.01), neck diameter >28mm (HR 3.5 [1.2-10.3], P = 0.02), neck length <20mm (HR 3.0 [1.1-8.6], P = 0.04), and neck angle>60 degrees (HR 3.4 [1.5-7.9], P = 0.004) were associated with higher rates of Type 1A endoleak, but not female sex, endograft, or the use of suprarenal fixation. 2 patients had proximal degeneration and 5 experienced graft migration. There were 2 ruptures (10%), and 13 patients underwent repair with 5 open conversions. Median survival after late Type 1A repair was 6.6 years (0-8.4 years).

CONCLUSION

Late appearing Type 1A endoleaks have a high rate of rupture and present significant diagnostic and management challenges. Careful surveillance is needed in patients with hostile neck anatomy and those who undergo intervention for other endoleaks. Adverse neck anatomy may be better suited for open repair or fenestrated/branched devices rather than conventional EVAR.

Endotension: twenty years of a controversial term

Use of the term endotension in the treatment of aortic aneurysm is currently controversial. Initially it was proposed to define the circumstance in which there is an enlargement of the aneurysm sac after endovascular repair without a demonstrable endoleak. The term was established with the aim of transmitting the possibility of causes other than pressure applying stress to the aneurysm wall. Twenty years have passed since the proposal of this terminology was published. The literature is reviewed with the purpose of providing an update on advances in the knowledge of the possible etiological mechanisms. The experimental studies call into question that causes other than pressure determine the increase of the aneurysm. On the basis of this review, the term `Sac Expansion Without Evident Leak´ (SEWEL) is proposed as a more accurate and precise denomination for what is aimed to be defined. Evidence suggests that the more likely mechanisms of persistent pressurization of the aneurysm sac are an unidentified endoleak (likely type I or low-flow Type II) or thrombus occluding wide and short channels that connects with the excluded aneurysm sac (at the attachment sites of the stent-graft or at the branch vessels orifices).

Endotension: What do we know and not know about this enigmatic complication of endovascular aneurysm repair

As the use of endovascular approaches to treat aneurysm repair continues to increase, more and more patients have been identified with endoleaks. Five types of endoleaks have been defined. Endotension, or type V endoleak, remains controversial owing to its variable definition across studies and the range of proposed treatments. Thus, we performed a review of the reported studies to summarize the diagnosis and treatment of this rare complication after endovascular aneurysm repair to determine what we do and do not know about this rare form of endoleak. The presence of an endoleak places patients at an increased risk of aneurysm sac enlargement and potential rupture. Although additional research is essential and yet difficult to perform, we sought to provide a guide for the management of this perplexing endoleak known as endotension.

Outcomes of type Ia endoleaks after endovascular repair of the proximal aorta

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) can be complicated by a type Ia endoleak. However, its natural history remains unclear. This report describes the natural history and midterm outcome of conservatively treated type Ia endoleaks in the proximal aorta.

METHODS

Between 2007 and 2015, 395 patients underwent TEVAR at our institution. Only TEVARs landing proximally at landing zones 0, 1, and 2 were included (221/395). Type Ia endoleak's flow was classified as "fast" or "slow" based on the time needed to visualize the aneurysmal sac during arteriogram.

RESULTS

The median follow-up was 4.1 years. Aortic dissection, thoracic aortic aneurysm, and traumatic aortic injury were the most common indications for TEVAR; the incidence of type Ia endoleak was not statistically different. Forty-seven patients (21.3%) had a type Ia endoleak. TEVAR landing proximally at zone 1 increased the odds of developing a type Ia endoleak (odds ratio, 2.8; 95% confidence interval, 1.3-5.9; P = .0072). The 30-day mortality and the overall survival was not influenced by the development of immediate-type Ia endoleak. In 34 (72.3%) patients, the endoleak resolved spontaneously. Ninety-four percent of these patients had a SlowE (n = 32/34). All of spontaneous resolutions occurred before the end of the first postoperative year.

CONCLUSIONS

SlowE tends to resolve within 1 year after TEVAR. Initial conservative treatment seems to be a reasonable approach in patients with SlowE.

Evolving concepts and management of endoleaks after endovascular aneurysm repair: where do we stand in 2019?

In recent years, there has been tremendous progress in endovascular aneurysm repair (EVAR) techniques and devices. This process has seen a change in incidence, risk factors, and treatment of endoleaks as well as in follow-up protocols after EVAR. In particular, recent literature has highlighted new concepts in the evaluation and prevention/treatment of type I and II endoleak after standard EVAR. There is also recent evidence regarding new imaging protocols for follow-up after EVAR, which include magnetic resonance imaging and contrast-enhanced ultrasound. This comprehensive review aims to outline the most recent concepts on imaging follow-up, pathophysiology/risk factors, and management of endoleaks.

A Narrative Review on Contrast-Enhanced Ultrasound in Aortic Endograft Endoleak Surveillance

Endovascular repair of abdominal aortic aneurysms have been performed successfully since 1991. However, 20% to 50% of these patients may develop an endoleak or continued aneurysmal sac expansion or perfusion despite stent graft coverage. Current recommendations suggest lifelong surveillance with computed tomographic angiography (CTA) at least 1 month after intervention and yearly after that. In select patients with a stable aneurysm sac on computed tomography performed 1 year after treatment, future screening could be performed with ultrasonography. However, color Doppler ultrasound can fail to detect as many as 31% of endoleaks. Contrast-enhanced ultrasound (CEUS) provides an alternative approach to excluded aneurysm sac follow-up imaging. The Society for Vascular Surgery notes a need for further research on the role of CEUS in endovascular aortic repair surveillance. The European Federation of Societies for Ultrasound in Medicine and Biology suggests that early results are promising. Meta-analyses report pooled sensitivities and specificities of CEUS compared with CTA for the detection of endoleak between 89% and 98% and 86% and 88%, respectively. Owing to the dynamic flow information it provides, CEUS may actually be more sensitive than CTA at detection and characterization in select circumstances. Challenges with adoption, patient selection, and operator dependency remain, but current and future research suggests a role for CEUS in endoleak surveillance.

Post-EVAR aneurysm sac shrinkage is prognostically favorable, but does not justify withholding follow-up

BACKGROUND

One of the main drawbacks of endovascular aortic aneurysm repair (EVAR) compared to open aortic surgery is the possibility of developing endoleaks and secondary aneurysm rupture, requiring frequent imaging follow-up. This study aims to identify prognostic factors that could be incorporated in follow-up protocols, which might lead to better personalized, lower cost and safe EVAR follow-up.

METHODS

A retrospective study was performed including all patients who underwent elective EVAR from January 2000 to December 2015. Follow-up data were gathered by reviewing medical files for radiographic imaging. Linear and logistic regressions were used to assess predictive factors for aneurysm shrinkage.

RESULTS

In 361 patients, aneurysm sac shrinkage of 10 mm or more was measured in 152 (42.1%) patients. Patients with ≥10-mm aneurysm shrinkage had fewer endoleaks (4.3% vs. 24.6%, P<0.0001) and fewer re-interventions for endoleak (3.0% vs. 10.1%, P=0.007). Aneurysm sac shrinkage was correlated with the absence of endoleak development (OR 0.36, 95% CI 0.19-0.66, P=0.001). In patients who had achieved ≥10-mm shrinkage of the aneurysm sac, no further significant growth was seen, compared to 38 (15.3%) patients who did not attain size reduction (P<0.001).

CONCLUSIONS

Once patients achieve ≥10-mm aneurysm sac shrinkage, they are less prone to developing subsequent aneurysm growth and have significantly lower risk of requiring surgery for endoleaks. However, a small number of patients remain at risk of requiring endoleak surgery after aneurysm shrinkage. Therefore, we would not recommend ceasing life-long imaging follow-up after significant aneurysm sac shrinkage, though it might be safe to increase the interval of follow-up.