The Suitability of Thoraco-abdominal Aortic Aneurysms for Branched or Fenestrated Stent Grafts – And the Development of a New Scoring Method to Aid Case Assessment

Complex abdominal aortic aneurysms: a review of radiological and clinical assessment, endovascular interventions, and current evidence of management outcomes

Endovascular aortic aneurysm repair (EVAR) is an established approach to treating abdominal aortic aneurysms, however, challenges arise when the aneurysm involves visceral branches with insufficient normal segment of the aorta to provide aneurysm seal without excluding those vessels. To overcome this, a range of technological developments and solutions have been proposed including fenestrated, branched, physician-modified stents, and chimney techniques. Understanding the currently available evidence for each option is essential to select the most suitable procedure for each patient. Overall, the evidence for fenestrated endovascular repair is the most comprehensive of these techniques and shows an early post-operative advantage over open surgical repair (OSR) but with a catch-up mortality in the mid-term period. In this review, we will describe these endovascular options, pre- and post-procedure radiological assessment and current evidence of outcomes.

Effect of aortic angulation on the outcomes of fenestrated-branched endovascular aortic repair

OBJECTIVE

To investigate the effect of aortic angulation on the early and midterm outcomes of fenestrated-branched endovascular aneurysm repair for thoracoabdominal aortic aneurysms (TAAA) or pararenal aortic aneurysms (PRAA).

METHODS

We retrospectively reviewed the data of consecutive patients enrolled in a prospective nonrandomized physician-sponsored investigational device exemption study (2013-2018). The infrarenal, suprarenal, and supraceliac aortic angles were measured on three-dimensional reconstructions of the preoperative computed tomography angiogram; a 45° cutoff was used for the analysis. End points were technical success, freedom from endograft-related complications (defined by type IA/IB/IIIA/IIIB/IIID endoleaks, and limb thrombosis); and freedom from target vessel instability (defined by branch-related death, occlusion, rupture or reintervention for stenosis, endoleak, or disconnection). Cox proportional hazard multivariable regression analyses were preformed to assess impact of covariates.

RESULTS

There were 298 patients treated for 102 PRAAs (34%) and 196 TAAAs (66%) (78 extent IV, 118 extent I-III) with 1156 renal-mesenteric vessels incorporated. An angulation of >45° was present in the infrarenal aortic axis in 94 patients (32%), suprarenal axis in 39 (13%), and supraceliac axis in 93 (31%). A supraceliac angle of >45° was more common with extent I-III TAAAs (P = .01). Technical success was 97% and was not significantly related to aortic angulation; the total operating time and fluoroscopy time were significantly longer in patients with any aortic angulation of >45°. Freedom from endograft-related complications was 93% (95% confidence interval [CI], 90%-97%) at 42 months, and was not associated with infrarenal (HR, 1.0; 95% CI, 0.4-2.9; P = .976), suprarenal (HR, 1.7; 95% CI, 0.5-1.8; P = .428), or supraceliac (HR, 0.9; 95% CI, 0.3-2.6; P = .886) aortic angles of >45°. Overall freedom from target vessel instability was 92% (95% CI, 90%-94%) at 42 months. By multivariable analysis, target vessel instability was not affected by an infrarenal angle of >45° (HR, 1.5; 95% CI, 0.9-2.4; P = .135) and a supraceliac angle of >45° (HR, 0.9; 95% CI, 0.5-1.5; P = .627), but was associated with a suprarenal angle of >45° (HR, 5.6; 95% CI, 3.5-9.1; P < .001), even after adjustment for aneurysm extent and type of bridging stent. In this subgroup of patients, the use of directional branch vs fenestration (P = .10) and the type of bridging stent (P = .10) did not significantly impact target vessel instability.

CONCLUSIONS

Fenestrated-branched endovascular aneurysm repair can achieve excellent early and midterm results among patients with an aortic angulation of >45°, with no increase in rates of graft-related complications. However, increased aortic angulation was associated with longer operative and fluoroscopy times. The suprarenal aortic angle was the most important determinant of more target vessel events, independent of stent design or which bridging stent was selected.

Use of the Octopus Endograft Technique to Reconstruct Renovisceral Arteries Arising From the False Lumen of a Rapidly Expanding Type B Aortic Dissection After Endovascular Repair

Purpose: To describe the use and 6-month outcomes of the octopus endograft technique to reconstruct renovisceral arteries arising from the false lumen (FL) of a type B aortic dissection after thoracic endovascular aortic repair (TEVAR). Case Report: A 46-year-old man post TEVAR for type B aortic dissection was admitted with persistent back pain and a rapidly expanding residual dissection. The celiac and left renal arteries arose from the FL and the superior mesenteric artery from both lumens, with the FL as its main supply. A 20% oversized Endurant stent-graft was deployed with the short limb just above the beginning of the dissection flap and the long limb in the aortic true lumen. A 120-mm-long Endurant extended limb was delivered antegradely via a conduit and deployed into the FL, with a 3-cm overlap with the short limb of the Endurant main body. The 3 renovisceral arteries were reconstructed by lining each with a series of Viabahn or Fluency stent-grafts whose proximal ends were subsequently placed parallel in the FL Endurant extended limb and dilated with kissing balloons. Imaging at 6 months showed an excluded FL, without stenosis or occlusion in the stent-graft or the renovisceral arteries. Conclusion: This case illustrates the successful use of the octopus endograft technique to reconstruct renovisceral arteries arising from a rapidly expanding FL in a post-TEVAR type B aortic dissection; the technique might be applicable in carefully selected patients.

Complementary Role of Fenestrated/Branched Endografting and the Chimney Technique in the Treatment of Pararenal Aneurysms After Open Abdominal Aortic Repair

Purpose: To evaluate the totally endovascular techniques for treating complex pararenal aortic aneurysms after open repair of abdominal aortic aneurysm. Methods: This retrospective study involved 34 men (mean age 74 years) with pararenal aortic aneurysms (22 pseudoaneurysms and 12 para-anastomotic aneurysms) that developed a median 11 years (range 4–22) after the primary surgical reconstruction. The median infrarenal neck length was 2 mm (range 0–9). Total endovascular aneurysm repair (EVAR) included the use of fenestrated (f-EVAR; n=17), branched (b-EVAR; n=11), combined f-EVAR/b-EVAR (n=1), and chimney (ch-EVAR; n=4) grafts and the “sandwich” technique (n=1). The primary outcome was aneurysm shrinkage >5 mm at latest follow-up. Secondary outcomes were target vessel patency, 30-day mortality, late survival, absence of type I and III endoleak, clinical success, and reintervention rate. Results: Technical success was 97% (n=33/34), while clinical success was achieved in 32 (94%) patients. The 30-day mortality was 3% (n=1/34). Mean follow-up was 23.2±16.6 months. One patient was lost to follow-up, and 1 patient underwent late open conversion for endograft infection. Six (18%) of the 33 surviving patients required a reintervention. Primary patency of the target aortic branches was 98% (109/111). Mean aneurysm diameter decreased from 64.1±10.2 to 56.7±16.9 mm (p<0.001) at latest follow-up. Midterm mortality was 12.1% (4/33). Estimated survival rates at 1 and 2 years were 93.9% and 90.9, respectively. Conclusion: Use of f-EVAR, b-EVAR, and ch-EVAR allows effective treatment of postsurgical pararenal aneurysms based on a clear algorithm and patient selection, highlighting the complementary character of these less invasive approaches.

[Aneurysms of the thoracic and thoracoabdominal aorta]

The incidence and operations of thoracic and thoracoabdominal aortic aneurysms have significantly increased. The indications for repair are considered to be a diameter of 6 cm or more and 5.5 cm for patient groups with increased risk of rupture. Complex open surgical repair is associated with significant mortality and complication rates. Total or hybrid endovascular repair seems to reduce early postoperative complications and mortality. The endovascular approach has evolved to be a good and predominant alternative to open repair of these aneurysms for older and high-risk patients as well as for aneurysms with optimal morphological suitability. Notwithstanding, at present a complete paradigm shift from open to endovascular repair for all patients, especially those with complex aneurysms, cannot yet be established.

Thoracic endovascular aortic repair: are we approaching total endovascular solutions for thoracic aortic disease?

Thoracic endovascular aortic repair (TEVAR) has become an attractive alternative treatment option for thoracic aortic disease. New devices and advanced image-guided procedures are continuously expanding the indications. This article focuses on currently available endovascular solutions for thoracic aortic disease and future 'all endovascular' directions of TEVAR. Currently available endovascular solutions, such as hybrid operations, chimney stent grafting and transapical stent graft deployment, for ascending aortic pathologies are presented. Additionally, the impact of upcoming new technologies, such as endovascular treatment of Stanford Type A dissections of the ascending aorta, is elaborated. With improving device technology, diverse available stent grafts and imaging modalities, TEVAR has become safer and holds promising potential to expand treatment options, especially for the ascending aorta and the aortic arch.

Tortuous iliac systems--a significant burden to conventional cannulation in the visceral segment: is there a role for robotic catheter technology?

PURPOSE

To attempt to quantify the effect of varying degrees of iliac tortuosity on maneuverability and "torquability" of endovascular catheters in the visceral segment, comparing conventional and robotic cannulation techniques.

MATERIALS AND METHODS

In a fenestrated endograft within a pulsatile phantom, 10 experienced operators cannulated the renal arteries via three different access vessels of varying iliac tortuosity with the use of conventional and robotic techniques. All procedures were performed in the angiography suite and recorded for blinded video assessment for quantitative (time, catheter-tip movements) and qualitative metrics (operator performance scores).

RESULTS

In total, 120 cannulations were observed. With increasing iliac tortuosity, median time and number of catheter movements required for renal cannulation with conventional techniques increased in stepwise fashion for mild, moderate, and severe iliac tortuosity (times, 7.6 min [interquartile range (IQR), 4.6-9.3 min] vs 6.9 min [4.2-11.4 min] vs 17.7 min [13.3-22.6 min], respectively; movements, 184 [IQR, 110-351] vs 251 [207-395] vs 569 [409-616], respectively). Median renal cannulation times were significantly reduced with the use of the robotic system irrespective of mild, moderate, or severe tortuosity (times, 1.4 min [IQR, 1.1-1.9 min] vs 3 min [2.3-3.3 min] vs 2.8 min [1.5-3.9 min], respectively; movements, 19 [IQR, 14-27] vs 46 [43-58] vs 45 [40-66], respectively; P < .005). Overall operator performance scores improved significantly with the use of the robotic system irrespective of iliac tortuosity severity.

CONCLUSIONS

In cases of moderate to severe iliac tortuosity, conventional catheter manipulation and control becomes an issue. The improvement in positional control and predictability seen with advanced catheter designs may be amplified in cases of severe iliac tortuosity.

Candidates and major determinants for endovascular repair of abdominal aortic aneurysms in Korean patients

The purpose of this study was to determine what proportion of patients with an abdominal aortic aneurysm (AAA) would be eligible for endovascular aneurysm repair (EVAR) and to examine the major determinants for suitability of EVAR with the currently available indications. We retrospectively reviewed 3-D reconstructed computed tomography angiography of 88 patients with an atherosclerotic AAA who underwent open repair or EVAR between October 2003 and October 2010 at the Cardiovascular Center, Seoul National University Bundang Hospital. Of the 88 patients, 71 (80.7%) were treated with open repair and 17 (19.3%) were treated with EVAR. The rate of minor complications, postprocedural intensive care unit stay, and total hospital stay were significantly lower in the EVAR group. When the suitability of EVAR was reevaluated using morphologic criteria, a total of 33 (37.5%) patients were considered eligible for EVAR. Multivariate analysis revealed that proximal neck length, proximal neck angle, and aneurismal sac size were independent determinants for suitability of EVAR. Taking into account the increased clinical experience and the availability of new devices, EVAR would be applicable in about 40% of atherosclerotic AAA cases in this series of Korean patients. Accurate identification of candidates for EVAR by detailed preoperative evaluation, especially for morphologic characteristics, is essential.