The importance of intraoperative transesophageal echocardiography in endovascular repair of thoracic aortic aneurysms

Endovascular repair of the aorta (EVAR) is a promising alternative to open repair. Transesophageal echocardiography (TEE) is a sensitive imaging modality for aortic disease. We reviewed our experience with TEE in thoracic EVAR. Seven patients underwent thoracic EVAR under general anesthesia. Intraoperative angiography and TEE were used to identify the extent of the aneurysm and guide placement of the stent. Doppler color flow was used to supplement angiography to detect flow within the aneurysmal sac after stent placement. The endograft was successfully deployed in six patients. Endoleak was identified by TEE in three patients and confirmed by angiography in two of them. EVAR was abandoned in one patient on the basis of TEE findings of extensive aortic dissection. We found TEE to be a valuable intraoperative tool for 1) identifying aortic pathology, 2) confirming that the guidewire is in the true lumen, 3) aiding stent graft positioning, and 4) supplementing angiography for detecting endoleaks. TEE can supplement information obtained by angiography to enhance the accuracy of EVAR and potentially improve outcomes. The anesthesiologist is ideally positioned to provide the endovascular team with vital information regarding stent positioning, endoleaks, and cardiac performance with a single imaging modality. IMPLICATIONS: Endovascular repair is an emerging alternative to open surgery for aortic aneurysms. We found transesophageal echocardiography to be a valuable imaging tool for guiding placement of the endograft, detecting leaks around the endograft, and supplementing information derived from angiography during endograft deployment.     

Acute traumatic rupture of the thoracic aorta treated with endoluminal stent grafts

BACKGROUND: Endovascular technologies provide a new therapeutic option in the treatment for acute traumatic rupture of the thoracic aorta. We report our experience with endoluminal stent graft repair of thoracic aortic ruptures. METHODS: Five patients underwent repair of the thoracic aorta with an endoluminal stent graft for acute traumatic rupture. Data from patient history, the procedure, hospital course, and follow-up were analyzed. RESULTS: All patient were involved in motor vehicle crashes. The mean Injury Severity Score was 51.8 +/- 6.38. All procedures were technically successful. Mean operating room time was 111 minutes and mean estimated blood loss was 200 mL. There were no cases of postprocedural endoleaks or conversions. There were no procedural complications, paraplegia, or deaths. Average follow-up was 20.2 months. CONCLUSION: Five cases of successful endograft repair of thoracic aortic rupture have been demonstrated. This should encourage future studies to determine whether endovascular repair of thoracic aortic ruptures is a safe and feasible alternative to conventional open repair.     

Combined fenestrated-branched endovascular repair of the aortic arch and the thoracoabdominal aorta

ObjectiveThe aim of our study was to evaluate patients who underwent extensive endovascular aortic stent graft coverage (from the aortic arch to abdominal aorta) in terms of early and midterm clinical outcomes.MethodsA retrospective multicenter study was undertaken. All patients were treated with extensive endovascular aortic stent graft coverage with fenestrated and branched endografts at three experienced endovascular centers.ResultsBetween 2012 and 2017, there were 33 patients (22 male [67%]) treated with a combination of fenestrated-branched stent grafts in the aortic arch and the thoracoabdominal aorta. Most of the patients (20/33 [61%]) had fenestrated-branched endovascular aneurysm repair (fb-EVAR) of the thoracoabdominal aorta as a second-stage procedure after thoracic arch (fb-Arch) repair, 10 had fb-Arch repair as the first procedure, and three patients had a single-stage procedure. The mean age was 67 ± 13 years, and the mean interval between procedures was 13 ± 12 months. For fb-Arch repair, 20 fenestrated and 13 branched devices were used; for fb-EVAR, 23 fenestrated, 5 branched, and 5 composite devices were used. The use of spinal drainage was more common in fb-EVAR (20/33 [61%]). Technical success was 100%. Mean hospital stay was 15 ± 13 days for fb-Arch repair and 12 ± 9 days for fb-EVAR. Two patients died in the hospital after fb-EVAR, resulting in a 30-day mortality of 6% (2/33). No deaths occurred during the fb-Arch repair component or in the single-stage cases. Four patients developed spinal cord injury (12%), 1 had permanent paraplegia (3%), and 2 patients had a neurologic event (1 stroke [3%] and 1 transient ischemic attack [3%]). Six patients (18%) died during a mean follow-up of 23 ± 17 months. The survival at 12 months after the second procedure was 72%, and the freedom from any reintervention was 82%. The 12-month freedom from reintervention was 87% for fb-Arch repair and 81% for fb-EVAR.ConclusionsExtensive endovascular coverage of the aorta for aortic disease seems to be a feasible procedure in experienced centers, with acceptable perioperative morbidity and mortality. Spinal cord ischemia appears acceptable despite extensive aortic coverage.     

Midterm results of stent-graft repair for thoracic aortic aneurysms: computed tomographic evaluation

Midterm observation of endovascular surgery using a fabric-covered stent graft for thoracic aortic aneurysms is discussed with postoperative follow-up findings based on regularly performed thoracic computed tomography (CT). From 1996 to 1999, 20 patients with thoracic aortic aneurysm underwent stent-graft placement in our hospital. One year follow-up CT results after placement were obtained for 17 patients. The CT scans found that there were both thrombosis and size reduction of aneurysm in 8 patients (46%), thrombosis without size reduction in 2 (13%), a new ulcerlike projection (ULP) in 3 (19%), persistent minor endoleakage in 2 (13%), a new endoleak in 1 (6%), and a recurrent endoleak from intercostal arteries in 1 (6%). The new ULP formation seemed to be a peculiar problem stemming from an intimal injury caused by edges of the stent. Therefore, we recently adopted a new spiral stent instead of the previous stent to avoid the injury. The new endoleak suggested that aneurysmal thrombosis without size reduction could cause the aneurysm to develop recurrent endoleaks. From these findings, we concluded that midterm observation of stent-graft repair for thoracic aortic aneurysms did not give satisfactory results. In order to improve the results of endovascular surgery using stent-grafts, we need to develop safer stent grafts with a reliable design to prevent endoleaks and to avoid intimal injury of the aorta. We also hope to develop effective technologies that can accelerate organization of thrombus in the aortic aneurysm after stent-graft placement.     

Outcomes of directional branches using self-expandable or balloon-expandable stent grafts during endovascular repair of thoracoabdominal aortic aneurysms

ObjectiveThe objective of this study was to evaluate outcomes of directional branches using self-expandable stent grafts (SESGs) or balloon-expandable stent grafts (BESGs) during fenestrated-branched endovascular aneurysm repair of thoracoabdominal aortic aneurysms.MethodsPatients treated by fenestrated-branched endovascular aneurysm repair were enrolled in a prospective study from 2014 to 2018. We included in the analysis patients who had target vessels incorporated by directional branches using either SESG (Fluency [Bard, Covington Ga] or Gore Viabahn [W. L. Gore & Associates, Flagstaff, Ariz]) or BESG (Gore VBX). Target artery instability (TAI) was defined by a composite of any stent stenosis, separation, or type IC or type IIIC endoleak requiring reintervention and stent occlusion, aneurysm rupture, or death due to target artery complication. End points included technical success, target artery patency, freedom from TAI, freedom from type IC or type IIIC endoleak, and freedom from target artery reintervention.ResultsThere were 126 patients (61% male; mean age, 73 ± 8 years) included in the study. A total of 335 renal-mesenteric arteries were targeted by directional branches using SESGs in 62 patients and 176 arteries or BESGs in 54 patients and 159 arteries. Patients in both groups had similar thoracoabdominal aortic aneurysm classification and aneurysm and target artery diameter, but SESG patients had significantly (P < .05) shorter stent length (−7 mm) and larger stent diameter (+1 mm) and more often had adjunctive bare-metal stents (72% vs 15%). Technical success was achieved in 99% of patients, with one 30-day death (0.7%). Mean follow-up was significantly longer among patients treated by SESGs compared with BESGs (23 ± 12 months vs 8±8 months; P < .0001). TAI occurred in 27 directional branches (8%), including 11 type IC endoleaks (2 SESGs, 9 BESGs), 10 stenoses (3 SESGs, 7 BESGs), 4 occlusions (3 SESGs, 1 BESGs), 4 type IIIC endoleaks (2 SESGs, 2 BESGs), and 1 stent separation (SESG), resulting in 20 target artery reinterventions in 16 patients (5 SESGs and 11 BESGs). At 1 year, SESGs had higher primary patency (97% ± 2% vs 96% ± 2%; P = .004), freedom from TAI (96% ± 2% vs 88% ± 3%; P < .0001), freedom from type IC or type IIIC endoleaks (98% ± 1% vs 92% ± 3%; P = .0004), and freedom from target artery reinterventions (98% ± 1% vs 88% ± 4%; P < .0001) compared with BESGs. There was no difference in secondary patency for SESGs and BESGs (98% ± 1% vs 99% ± 1%; P = .75). Factors associated with TAI were large stent diameter (odds ratio, 0.6; P < .0001) and use of VBX stent graft (odds ratio, 6.5; P < .0001).ConclusionsDirectional branches were associated with high technical success and low rates of stent occlusion, independent of stent type. However, primary patency, freedom from TAI, and freedom from type IC or type IIIC endoleaks was lower for BESGs compared with SESGs.     

Duplex ultrasound imaging with an ultrasound contrast agent: the economic alternative to CT angiography for aortic stent graft surveillance

The use of endovascular stent graft repair for aortic aneurysmal disease has become increasingly common, with the added requirement for close postoperative surveillance to detect the presence of endoleaks or graft migration. The most commonly used technique for surveillance is computed tomography (CT) angiography, with the need for intravenous contrast posing 1 limitation in those patients with renal dysfunction and the cost of this testing presenting an economic limitation. Early results of duplex imaging in the authors' Vascular Laboratory using an intravenous ultrasound contrast agent have shown sensitivity and specificity equivalent to those of CT angiography, with no evidence of any related morbidity. They have evaluated the cost effectiveness of using duplex ultrasound imaging as the primary surveillance technique for postoperative follow-up in aortic stent graft patients. Surveillance protocols now require that 8 follow-up examinations be performed in the first 3 years after stent graft placement. The charges for CT angiography in their institution average 2,779 dollars per study, for a 3-year total of 22,232 dollars per patient. The charges for aortic duplex ultrasound average 525 dollars per study, with a 3-year total of 4,200 dollars per patient. Adding the cost of routine abdominal radiographs to confirm stent graft position (147 dollars per study) would bring this 3-year total to 5,376 dollars, a savings of 16,856 dollars per patient. For every 100 patients who are followed up after stent graft placement, this represents a 3-year savings of more than 1.6M dollars. Promising early results of duplex ultrasound imaging with an intravenous contrast agent show sensitivity and specificity equivalent to those of CT angiography in detecting aneurysm size and graft endoleaks or other hemodynamic abnormalities. If these results can be demonstrated in larger patient series, this technique should become the method of choice for stent graft surveillance, for it offers very significant economic advantages and avoids the complications of intravenous contrast-induced renal dysfunction.     

Prospective nonrandomized study to evaluate cone beam computed tomography for technical assessment of standard and complex endovascular aortic repair

ObjectiveThe objective of this study was to analyze the utility of cone beam computed tomography (CBCT) for technical assessment of standard and complex endovascular aneurysm repair (EVAR).MethodsData of consecutive patients who underwent standard or complex EVAR in 2016 and 2017 at our institution were entered into a prospective database and analyzed retrospectively. There were 154 patients (126 male; mean age, 74 ± 8 years) enrolled in a prospective study between 2016 and 2017. A total of 170 aortic procedures were investigated, including 85 fenestrated-branched EVARs (F-BEVARs), 42 abdominal and thoracic EVARs, 32 EVARs with iliac branch devices, and 11 aorta-related interventions. Technical assessment was done using CBCT with and without contrast enhancement, digital subtraction angiography (DSA), and computed tomography angiography (CTA). Patients with stage 3B or stage 4 chronic kidney disease had CBCT without contrast enhancement. Radiation exposure (mean dose-area product), effective dose (ED), and amount of iodine contrast agent were analyzed. End points were presence of any endoleak, positive findings warranting possible intervention (stent kink or compression, type I or type III endoleak, dissection, thrombus), and need for secondary intervention.ResultsRadiation exposure and amount of iodine contrast agent were significantly higher (P < .05) for F-BEVAR compared with other aortic procedures (174±101 Gy∙cm² vs 1135±113 Gy∙cm² and 144±60 mL vs 122±49 mL). ED averaged 74±36 mSv for the aortic procedure, 18 ± 18 mSv for fluoroscopy, 7 ± 7 mSv for DSA acquisition, 15±7 mSv for CBCT, and 34±17 mSv for CTA imaging (P < .001). Endoleak detection was significantly higher (P < .001) with CBCT (53%) compared with DSA (14%) and CTA (46%). CBCT identified 52 positive findings in 43 patients (28%), higher for F-BEVAR compared with other aortic procedures (35% vs 16%; P = .01). Positive findings included stent compression or kink in 29 patients (17%), type I or type III endoleak in 16 patients (10%), and arterial dissection or thrombus in 7 patients (5%). Of these, 28 patients (18%) had positive findings that prompted an intraoperative (17%) or delayed intervention (1%). Another 15 patients (10%) with minor positive findings were observed with no clinical consequence. DSA alone would not have detected positive findings in 34 of 43 patients (79%), including 21 patients (49%) who needed secondary interventions. CTA diagnosed two (1%) additional endoleaks requiring intervention (one type IC, one type IIIC) that were not diagnosed by CBCT. Replacing DSA and CTA by CBCT would have resulted in 53% ± 13% reduction in amount of iodine contrast agent and 55% ± 12% reduction in ED (P < .05).ConclusionsCBCT reliably detected positive findings prompting immediate revisions in nearly one of five patients, with the highest rates among F-BEVAR patients. Detection of any endoleak was higher with CBCT compared with DSA or CTA, but most endoleaks were observed. DSA alone failed to detect positive findings warranting revisions.     

Anesthetic management for distal aortic arch aneurysm stent grafting

A 76-year-old woman with thoracic aortic aneurysm involving distal aortic arch was scheduled for graft replacement from ascending to proximal aortic arch with endovascular stent graft to descending aorta. Surgical procedures were performed under median sternotomy with hypothermic systemic circulation arrest and selective cerebral perfusion. The stent graft composed of 30 mm Gianturco Z stent and 27.5 mm woven Dacron graft was introduced into the descending aorta under the guidance of transesophageal echocardiography (TEE) and fluoroscopy. Ascending and proximal aortic arch replacement was then performed with four branched woven Dacron graft. The aortic pathology was confirmed by TEE and the extent of the aneurysmal lesion was defined. TEE was also useful to find the dislodgement of the stent graft after deployment. This surgical technique, being less invasive than conventional thoracotomy, would be indicated for elderly patients with distal aortic arch aneurysm. TEE is the vital imaging technique for placement of the stent graft, as well as for intraoperative cardiac monitoring.     

Stent grafts for the thoracic aorta: a new paradigm?

The treatment of thoracic aortic pathology is complicated by the morbidity of the surgical procedure, and the comorbidities encountered in an elderly population. Stent grafts have now been used for approximately 10 years for the treatment of thoracic aneurysmal disease, management of aortic dissections, intramural hematoma, and giant penetrating ulcers, and for traumatic aortic tears, with impressive early results. However, these efforts have been significantly limited by the lack of a commercially available stent graft specifically designed for the thoracic aorta, the lack of real long-term follow-up, and the failure of experience in the abdominal aorta to translate to the thoracic aorta. Nevertheless, significant and even unique therapies have been enabled by stent graft technology for the treatment of the above-mentioned diseases. It is likely that, with more sophisticated technology and improved understanding of thoracic aortic pathology, stent graft use will expand, and its utility will be further clarified.     

Risk factors for target vessel endoleaks after physician-modified fenestrated or branched endovascular aortic repair for postdissection thoracoabdominal aortic aneurysms

ObjectivePatients with postdissection thoracoabdominal aortic aneurysms (TAAAs) have been more likely to develop endoleaks than those with degenerative TAAAs after fenestrated or branched endovascular aortic repair (F/BEVAR). In the present study, we aimed to determine the risk factors for target vessel (TV)-related endoleaks after visceral segment F/BEVAR for postdissection TAAAs.MethodsWe performed a retrospective analysis of all patients with degenerative and postdissection TAAAs treated with F/BEVAR between 2017 and 2021. All the patients had undergone computed tomography angiography before and 3 months, 6 months, and annually after discharge. Two experienced vascular surgeons had used data from computed tomography angiography and vascular angiography to judge the presence of endoleaks. The study end points were mortality, aneurysm rupture, and the emergence of and reintervention for TV-related endoleaks.ResultsA total of 195 patients (mean age, 66 ± 10 years; 69% men) had undergone F/BEVAR for 99 postdissection TAAAs and 96 degenerative TAAAs. During a mean follow-up of 16 ± 12 months, we found that the patients with postdissection TAAAs were younger (age, 64 ± 10 years vs 69 ± 9 years; P = .001), had required more prior aortic repairs (58% vs 40%; P = .012), and had had a higher body mass index (26.1 ± 3.4 kg/m² vs 24.8 ± 3 kg/m²; P = .008), a larger visceral segment aortic diameter (47.1 ± 7.5 mm vs 44.5 ± 7.5 mm; P = .016), and more TV-related endoleaks (18% vs 7%; P = .023) compared with those with degenerative TAAAs. Of the 99 patients with postdissection TAAAs, 327 renal–mesenteric arteries were revascularized using 12 scallops, 141 fenestrations, and 174 inner or outer branch stents. A total of 25 TV-related endoleaks were identified among 18 patients during follow-up, including 6 type Ic (retrograde from the distal end of the branch), 3 type IIIb (bridging stent fabric tear), and 16 type IIIc endoleaks (detachment or loose connection of the bridging stent). The patients with an endoleak had had a larger visceral aortic diameter (52.7 ± 6.4 mm vs 45.8 ± 7.2 mm; P < .001) and had undergone revascularization of more TVs (3.7 ± 0.7 vs 3.2 ± 0.9; P = .032). In contrast, true lumen compression did not seem to affect the occurrence of TV endoleaks (39% vs 27%; P = .323). The use of presewn branch stents in the fenestration position was associated with a lower risk of TV-related endoleaks (5% vs 11%; P = .025). In addition, TVs derived entirely or partially from the false lumen were more prone to the development of endoleaks after reconstruction (19% vs 4% [P < .001]; and 15% vs 4% [P = .047], respectively).ConclusionsWe found that patients with postdissection TAAAs were more likely to have TV-related endoleaks after F/BEVAR in the visceral region than those with degenerative TAAAs. Additionally, patients with a larger aortic diameter and a greater number of fenestrations in the visceral region were more likely to have experienced TV-related endoleaks. Branch vessels deriving from the false lumen were also more likely to develop endoleaks after reconstruction, and prefabricated branch stents were related to a lower possibility of TV-related endoleaks.     

Endovascular repair of a ruptured thoracic aortic dissection with a right sided aortic arch: A case report

BackgroundEmergency treatment of complex aortic pathology is challenging in the setting of a right-sided aortic arch. We report the successful treatment of a ruptured thoracic aortic aneurysm (TAA) in the setting of a Stanford type B aortic dissection (TBAD) and right-sided aortic arch.Presentation of caseThe patient is a 66-year-old male with chronic kidney disease (CKD) admitted with right sided chest pain and hypotension. Computed tomography angiography (CTA) revealed a 5 cm ruptured TAA in the setting of a TBAD and right-sided aortic arch. The TBAD began just distal to the right common carotid artery and involved the origin of the left subclavian artery (SCA). Using a totally percutaneous approach, a conformable Gore^® TAG^® thoracic endoprosthesis was placed in proximal descending thoracic aorta covering the left SCA. Aside from progression of his pre-existing CKD, the patient had an uneventful recovery. CTA one-month post-procedure revealed a type IB endoleak with degeneration of the distal descending thoracic aorta. To exclude the endoleak, the repair was extended distally using a Medtronic Valiant^® thoracic stent graft. The left subclavian artery was subsequently coil embolized to treat an additional retrograde endoleak. The patient has done well with no further evidence of endoleak or aneurysm expansion.ConclusionRight-sided aortic arch presents challenges in the emergency setting. CTA and post-processing reconstructions are very helpful. While the endoleaks prompted additional interventions, the end result was excellent. This case displays the importance of careful attention to detail and follow-up in these complicated patients.     

Feasibility of the Inoue single-branched stent-graft implantation for thoracic aortic aneurysm or dissection involving the left subclavian artery: short- to medium-term results in 17 patients

OBJECTIVE: This study assessed the short- to medium-term clinical results of the Inoue single-branched stent graft for repair of thoracic aortic aneurysms or dissections involving the left subclavian artery. METHODS: A retrospective review of experiences at two institutions was performed. We analyzed the data of consecutive 17 patients with thoracic aortic aneurysms or dissections who underwent endovascular repairs with the Inoue single-branched stent graft between July 1999 and April 2004. Complete baseline and follow-up data were available on all patients. The mean age was 71 +/- 9 years, and 13 of the patients (76%) were men. Eight patients (47%) were considered unfit for open surgery because of advanced age or the presence of comorbid diseases. RESULTS: The stent grafts were successfully delivered and deployed in all 17 patients. Periprocedural major complications, defined as those that caused any persistent disorder, occurred in one patient who developed spinal ischemia. A postoperative computed tomographic scan revealed three attachment site endoleaks; two endoleaks were from the proximal attachment sites and one endoleak was from the distal attachment site. The mean follow-up period was 26 months (range, 7 to 65 months). Two deaths occurred in the follow-up period from cerebral bleeding and pneumonia, both considered unrelated to the stent grafting. Two patients with attachment site endoleaks needed secondary stent-grafting; one patient required the implantation of a straight stent-graft in the distal attachment site and the other, the implantation of a double-branched stent-graft. Another patient with attachment site endoleak was considered very high-risk for open surgery or secondary stent grafting and did not undergo secondary intervention. The aneurysmal sac size of the patient has been stable for 28 months. The branched section of the stent graft was patent in all patients in the follow-up period. CONCLUSION: The results demonstrate the feasibility of the Inoue single-branched stent graft for thoracic aortic aneurysms or dissections involving the left subclavian artery.     

Analysis of predisposing factors for type III endoleaks from directional branches after branched endovascular repair for thoracoabdominal aortic aneurysms

BackgroundMid-term durability of branches has already been established, and BF-branched and fenestrated endovascular repair has shown comparable results with open repair in the treatment of thoracoabdominal aortic aneurysms (TAAAs). Nevertheless, target vessel instability remains the most frequent adverse event after complex endovascular aortic repair. Type III endoleaks from directional branches have been reported with a low incidence, but risk factors for this complication have not been investigated yet.MethodsThis was a dual-center observational retrospective cohort study. Data were collected prospectively for each patient treated with branched endovascular repair between April 2008 and December 2019. The primary outcome was to assess potential risk factors for branch disconnection and fracture. A logistic regression analysis was performed, including preoperative and postoperative measurements as well as intraoperative details. A Cox regression hazard analysis was performed to evaluate the influence of preoperative aneurysm diameter and target vessel angulation on the outcome during follow-up.ResultsTwo hundred ninety-five target visceral vessels (TVVs) in 91 patients were considered suitable for cannulation. Technical success was 96.9% (286/295 TVVs). The median follow-up was 32.5 months (interquartile range, 14.2-50.1 months). Twelve type III endoleaks from directional branches were detected (4.2%; 5 bridging stent graft fractures and 7 disconnections). Five type III endoleaks involved the celiac trunk (one fracture and four disconnections), five the superior mesenteric artery (four fractures and one disconnection), and two the renal arteries (both disconnections). The median time to type III endoleak was 22.2 months (interquartile range, 10.9-37.6 months). Preoperative TAAA diameter (P = .028), preoperative TVV angulation (P = .037), the use of a BeGraft stent graft as bridging stent graft (P = .001), and different stent types on the same vessel (P = .048) were associated with type III endoleak at univariable analysis. Using a BeGraft stent graft (P = .010) was the only significant factor predisposing to type III endoleak at multiple logistic regression. The Cox regression analysis showed a two-fold increased risk for type III endoleak for every 10-mm increase in preoperative TAAA diameter (hazard ratio, 2.00; 95% confidence interval, 1.08-3.72; P = .028) and a 1.5 increased risk every 12° increase of preoperative TVV angulation (hazard ratio, 1.47; 95% confidence interval, 1.02-2.10; P = .037).ConclusionsType III endoleaks from directional branches are a non-negligible complication after branched endovascular repair, with a relevant incidence. They tended to be clustered on specific patients, and aneurysm diameter and TVV angulation are strictly associated with the outcome. Different stent types on the same vessel should be avoided whenever possible. An intensified follow-up should be adopted for patients with large aneurysms, implanted with first-generation BeGraft, or who have been already diagnosed with type III endoleaks.     

Midterm results of transluminal endovascular grafting in patients with DeBakey type III dissecting aortic aneurysms.

OBJECTIVE: Transluminal endovascular grafting (TEG) is less invasive than conventional operative procedures for the treatment of DeBakey type III dissecting aortic aneurysms (DAA). We have used two different kinds of stent grafts covered with woven Dacron grafts, a Gianturco Z-stent graft (G-SG) and a Spiral Z-stent graft (S-SG). Because the G-SG lacks adequate flexibility, the end of the graft may injure the intima after long-term deployment in the proximal descending aorta. We have used S-SGs, which are more flexible than G-SG, to improve outcome. We report our late midterm results and discuss treatment policy. SUBJECTS AND METHODS: We studied 45 patients with DeBakey type III DAA. Thirty-two G-SGs and 13 S-SGs were used. Follow-up ranged from 1 year 6 months to 8 years 5 months (mean, 5 years 2 months). RESULTS: 1) Surgical outcome: (a) TEG was technically successful in all patients. There was no operative mortality. (b) One week after surgery, 36 patients had no endoleaks, 5 had minor endoleaks, and 4 had major endoleaks. 2) Late midterm results: (a) Four patients with residual major endoleaks, underwent replacement of the descending thoracic aorta. (b) Intimal injury occurred at the distal end of the stent graft 4 to 18 months (mean, 10.5 months) after surgery in 12 patients with G-SG and 1 with S-SG. One of these patients had recurrent dissection, and 12 had ulcer like projections (ULP). Two patients underwent additional stent implantation to block blood flow. (c) Four patients with S-SG had major endoleaks 3 to 6 months after surgery. In 3 of these patients, the Spiral Z-stents were compressed and occluded, and thrombus had formed in the lumen. Three patients underwent replacement of the descending thoracic aorta. (d) Additional replacement of the descending thoracic aorta was done in 9 of the 45 patients (20%) 4 to 24 months after TEG. All patients responded to treatment and were discharged from the hospital. CONCLUSION: Intimal injury was caused by Gianturco Z-stents because of inadequate flexibility, and endoleaks and stent-graft occlusion were caused by Spiral Z-stents because of insufficient radial force against the aortic wall. The development of stents with these improved properties is expected to further improve outcome.     

Efficacy of ultrasound scan contrast agents in the noninvasive follow-up of aortic stent grafts

OBJECTIVE: Computed tomographic angiography (CTA) is currently the most commonly used technique for postoperative surveillance to detect endoleaks after endovascular stent graft repair of abdominal aortic aneurysms. We have evaluated the efficacy of duplex ultrasound scan with the addition of an ultrasound scan contrast agent in documenting endoleaks and compared these results with CTA. METHODS: Conventional duplex ultrasound scan with color Doppler imaging (CDI) was first done as part of routine postoperative surveillance. After the CDI study, a 1-mL bolus of ultrasound scan contrast was given via an antecubital vein, followed by a 5-mL flush with normal saline solution. The duplex ultrasound scan evaluation of the stent graft was repeated once the contrast agent was circulating throughout the blood pool, with tissue harmonic imaging to optimize visualization of the contrast agent. Status of the stent graft, the presence or absence of any endoleak, and whether these endoleaks were graft related (group I) or arterial branch related (group II) were recorded. Findings were compared with CTA studies done within a 2-week period of the ultrasound scan examination. RESULTS: Twenty patients were evaluated, 18 with modular stent grafts and two with unibody bifurcated stent grafts. Patients had a mean age of 74.5 +/- 7.6 years; 19 were male, with only one female. All stent grafts remained widely patent with normal aortoiliac flow hemodynamics. Duplex ultrasound scan with contrast identified all eight of the endoleaks seen with CTA and was able to determine whether they were group I or group II leaks. In two patients, ultrasound scan with contrast detected small endoleaks at the proximal graft attachment site, with extravasation of contrast into the aneurysm sac during systole. These endoleaks were not seen with CTA but were confirmed with conventional angiography at the time of endovascular closure. Standard duplex ultrasound scan with CDI failed to identify four of the 10 endoleaks in patients with technically difficult conditions. CONCLUSION: Duplex ultrasound scan, when used with an intravenously administered ultrasound scan contrast agent in the noninvasive follow-up of patients with aortic stent grafts, appears to provide good sensitivity to the presence and type of endoleaks, even in patients with technically difficult conditions not amenable to conventional duplex ultrasound scan with CDI.     

Contrast-enhanced Duplex surveillance after endovascular abdominal aortic aneurysm repair: improved efficacy using a continuous infusion technique

INTRODUCTION: Currently, postoperative endoleak surveillance after endovascular aortic aneurysm repair (EVAR) is primarily done by computed tomography (CT). The purpose of this study was to determine the efficacy of contrast-enhanced ultrasonography scans to detect endoleaks by using a novel infusion method and compare these findings with those of CT angiography (CTA). METHODS: Twenty male patients (mean age, 70.4 years) underwent surveillance utilizing both CTA and contrast-enhanced color Duplex imaging. One 3-mL vial of Optison (Perfluten Protein A microspheres for injection) and 57 mL normal saline, for a total of 60 mL, were administered to each patient as a continuous infusion at 4 mL/min via a peripheral vein. Each study was optimized with harmonic imaging, and a reduced mechanical index of 0.4 to 0.5, compression of 1 to 3, and a focal zone below the aorta to minimize microsphere rupture. One minute was allowed from the time of infusion to the appearance of contrast in the endograft. Flow was evaluated within the lumen of the graft and its components, as was the presence or absence of endoleaks. Findings were compared with standard color-flow Duplex imaging and CT utilizing CTA reconstruction protocols. RESULTS: All patients evaluated had modular endografts implanted for elective aneurysm repair. Contrast-enhanced duplex scans identified nine endoleaks: one type I and eight type II. No additional endoleaks were seen on CTA. However, CTA failed to recognize three type II endoleaks seen by contrast-enhanced ultrasound. The continuous infusion method allowed for longer and more detailed imaging. An average of 46.8 mL of the contrast infusion solution was used per patient. CONCLUSIONS: Contrast enhanced Duplex ultrasonography accurately demonstrates endoleaks after EVAR and may be considered as a primary surveillance modality. Continuous infusion permits longer imaging time.     

Physiologic coarctation of the aorta resulting from proximal protrusion of thoracic aortic stent grafts into the arch

Graft collapse is a known complication of thoracic aortic stent grafting, particularly in cases of traumatic thoracic aortic transection, when a typically smaller diameter aorta is repaired with a relatively large diameter device. In contrast, obstruction of the aorta from a stent graft that protrudes into the aortic arch but does not collapse is a less common complication of thoracic aortic stent grafting that can present as a functional aortic coarctation. We describe here two cases of physiologic coarctation of the aorta caused by stent graft protrusion into the arch that were successfully treated with stent graft explantation and open aortic reconstruction.     

Usefulness of intraoperative transesophageal echocardiography in stent graft implantation for thoracic descending aorta

BACKGROUND: Stent graft implantation for thoracic descending aorta is a promising alternative to open repair. Transesophageal echocardiography (TEE) is a sensitive imaging modality for aortic disease. We reviewed our experience with TEE in stent graft implantation for thoracic descending aorta. METHOD: Five patients underwent stent graft implantation for thoracic descending aorta under general anesthesia. Intraoperative angiography and TEE were used to identify the extent of the aneurysm and the placement of the stent. RESULTS: TEE showed stent graft configuration and presence of leakage in all cases. In three cases, additional stent graft placement or bypass was performed. CONCLUSIONS: Useful information was obtained by TEE in enhancing the accuracy of stent graft positioning potentially improving outcomes. TEE may facilitate repair by confirming aortic pathology, identifying endograft placement, and assessing the adequacy of aneurysm sack isolation, presence of leakage, as well as dynamic intraoperative cardiac performance.     

Endoleakage after stent-graft treatment of abdominal aneurysm: Implications on pressure and imaging—an in vitro study

Background: Endoleakage is a fairly common problem after endovascular repair of abdominal aortic aneurysm and may prevent successful exclusion of the aneurysm. The consequences of endoleakage in terms of pressure in the aneurysmal sac are not exactly known. Moreover, the diagnosis of endoleakage is a problem because visualization of endoleaks can be difficult. Method: With an ex vivo model of circulation with an artificial aneurysm managed by means of a tube graft, studies were performed to evaluate precisely known diameters of endoleaks with both imaging techniques (computed tomography and digital subtraction angiography) and pressure measurements of the aneurysmal sac. The experiments were performed without endoleak (controls) and with 1.231-French (0.410 mm), 3-French (1 mm), and 7-French (2.33 mm) endoleaks. Pressure and imaging were evaluated in the absence and presence of a simulated open lumbar artery. The pressure in the prosthesis and in the aneurysmal sac were recorded simultaneously. Digital subtraction angiography with and without a Lucite acrylic plate, computed tomographic angiography, and delayed computed tomographic angiography were performed. For the first experiments, the aneurysmal sac was filled with starch solution. All tests were repeated with fresh thrombus in the aneurysmal sac. Results: Each endoleak was associated with a diastolic pressure in the aneurysmal sac that was identical to diastolic systemic pressure, although the pressure curve was damped. At digital subtraction angiography without a Lucite acrylic plate, the 1.231-French (0.410 mm) endoleak was visualized without an open lumbar artery. When a Lucite acrylic plate was added, the endoleak was not visible until a lumbar artery was opened. In the presence of thrombus within the aneurysmal sac, all endoleaks were not visualized at digital subtraction angiography. At computed tomographic angiography, all endoleaks were not visualized in the absence of a thrombus mass in the aneurysmal sac. In the presence of thrombus within the aneurysmal sac, the 1.231-French (0.410 mm) endoleak became visible after opening of a simulated lumbar artery. At delayed computed tomographic angiography, all endoleaks were visualized without and with thrombus. Conclusion: Every endoleak, even a very small one, caused pressure greater than systemic diastolic pressure within the aneurysmal sac. However, small endoleaks were not visualized with digital subtraction angiography and computed tomographic angiography, whereas all endoleaks were visualized with a delayed computed tomographic angiography protocol. We believe that follow-up examinations after stent graft placement for aortic aneurysms should focus on pressure measurements, but until this is clinically feasible, delayed computed tomographic angiography should be performed. (J Vasc Surg 1998;28:234-41.)     

The use of a low-profile stent graft with a polymer ring sealing technology combined with bare renal stent (vent technique) in patients with juxtarenal aneurysm not eligible for open surgery and fenestrated endograft

ObjectiveIn cases of juxtarenal abdominal aortic aneurysm (jAAA), endovascular aneurysm repair (EVAR) involves the use of custom-made fenestrated stent grafts, which usually need large-diameter access vessels, superior costs, and a certain time between graft planning and delivery. We report our preliminary experience using the bare renal stent technique (called vent) in combination with the ultralow-profile stent graft Ovation (Endologix, Irvine, Calif) to seal jAAAs in patients evaluated to be unfit for open surgery and not suitable for fenestrated endograft.MethodsA single-center retrospective review of jAAAs treated by Ovation vent technique from January 2015 to December 2018 was conduced. The vent procedure consisted of a modified, off-label deployment of the sealing ring of the ultralow-profile Ovation stent graft close to renal orifices in combination with short bare-metal stents. The exclusion criterion was a diameter >31 mm at the level of the lowest renal artery. Early technical and clinical results, estimated midterm survival, renal artery patency, freedom from type IA endoleak, freedom from reintervention, and freedom from neck enlargement (>2 mm) were reported.ResultsOverall, 38 patients had jAAA and were considered unfit for open repair and not eligible for fenestrated EVAR. The proximal neck was <5 mm in all cases (mean, 3.3 ± 1.2 mm). Vent renal stents were implanted bilaterally in 16 patients. Primary technical success was 94.7% (36/38), with satisfactory cannulation of all renal arteries and sealing of the aneurysm in all but two cases because of type IA endoleaks that were treated immediately with success. Primary clinical success at 1 month was 100%. During a median follow-up period of 22.4 ± 3.6 months (range, 1-46 months), no abdominal aortic aneurysm-related deaths occurred, and no patient was lost to follow-up. The survival curve at 1 year and 2 years was, respectively, 96.4% and 91.6% (standard error, 0.57%). There were no cases of neck dilation or endograft migration. Freedom from reintervention at 12 months and 24 months was 100% and 89.5%, respectively (standard error, 0.7%); freedom from type IA endoleak was 100% and patency of the renal artery was 100% at 2 years.ConclusionsThe described technique includes the use of a low-profile stent graft with a polymer ring sealing technology combined with bare renal stents that are not competing for the same room. This early experience shows that the vent technique is safe and feasible and increases the range of treatment of those patients with jAAA who are unfit for open repair and for fenestrated EVAR because of several anatomic constraints.