Open Distal Fenestration of Chronic Dissection Facilitates ...

Open Distal Fenestration of Chronic Dissection Facilitates Endovascular Elephant Trunk Completion: Late Outcomes Muhammad Aftab, MD, Jay J. Idrees, MD, Frank Cikach, BS, Jose L. Navia, MD, Donald Hammer, MD, and Eric E. Roselli, MD Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado, Denver, Colorado; Aorta Center and Department of Thoracic and Cardiovascular Surgery, Heart and Vascular Institute, Cleveland Clinic, Cleveland; Cleveland Clinic Lerner College of Medicine, Cleveland; and Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio

Background. Retrograde false lumen perfusion is a common mode of failure after stent grafting chronic aortic dissection. Open fenestration during the first-stage elephant trunk (ET) creates a landing zone for secondstage endovascular ET completion in patients with a false lumen aneurysm. Our objectives were to assess long-term safety and durability of this technique. Methods. From 2007 to 2014, 56 patients with thoracoabdominal dissection and aneurysm underwent stage 1 ET and open fenestration. Fifteen (26.8%) patients had DeBakey type III dissection, and 41 (73%) had type I, 38 (68%) with previous ascending repair. Mean maximum diameter was 5.8 ± 1 cm. Imaging follow-up was complete in all survivors. Results. Endovascular ET completion was performed in 49 patients (87.5%), urgently in 11 (22%). Operative mortality after the first stage was 1.8%. The ET in 8 patients was performed prophylactically. Complications after the first stage included transient ischemic attack in 1 patient (1.8%), subdural hemorrhage in 1 (1.8%), tracheostomy in 1 (1.8%), bleeding in 5 (8.9%), and paraplegia in

1 (1.8%). All 48 patients had false lumen thrombosis in the treated segment without endoleak or retrograde perfusion. The aneurysm sac shrunk in 67%, with a mean overall aortic diameter reduction of 1 ± 0.8 cm. Median follow-up was 33.8 months. Eight patients (16%) underwent 11 late reinterventions, comprising thoracic endovascular aortic repair extension in 4 patients (36%), thoracic endovascular aortic repair and false lumen embolization in 3 (27%), open thoracoabdominal aortic aneurysm completion repair in 2 (18%), and redo proximal repair for infection in 2 (18%). There were 6 late deaths. Conclusions. Open aortic fenestration to create a distal landing zone during stage 1 ET facilitates endovascular completion for chronic dissection with false lumen aneurysm. The technique is safe, effective, and durable. It promotes reverse aortic remodeling and eliminates retrograde false lumen flow.

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Although the ET provides a stable proximal landing zone for the stent graft, the distal landing zone is less reliable in chronic dissection. Retrograde false lumen perfusion from distal entry tears is a common mode of failure after stent grafting of chronic dissection. We previously described a novel hybrid approach involving open distal descending aortic fenestration to create a reliable landing zone as an adjunct to the first-stage arch repair and ET construction. The thoracic aortic repair is then completed as a TEVAR extending from the ET to the

rogressive aneurysmal degeneration of the aortic false lumen after successful repair of acute DeBakey type I aortic dissection or after type III aortic dissection is common [1]. Many patients require multiple interventions as a result of the progressive growth of residual aortic dissection. A two-staged approach consisting of proximal repair with elephant trunk (ET) reconstruction, followed by distal repair, is a commonly used strategy [2–9]. Thoracic endovascular aortic repair (TEVAR) is increasingly used to treat chronic dissections but is limited by the adequacy of proximal and distal landing zones. Hybrid aortic repair consisting of second-stage endovascular ET completion (EEC) addresses the proximal landing zone and has been shown to be safe and effective [10, 11].

(Ann Thorac Surg 2017;-:-–-) Ó 2017 by The Society of Thoracic Surgeons

Dr Roselli discloses a financial relationship with Bolton, Cook, Gore, Medtronic, and Vascutek.

Accepted for publication May 15, 2017. Presented at the Fifty-second Annual Meeting of The Society of Thoracic Surgeons, Phoenix, AZ, Jan 23–27, 2016. Address correspondence to Dr Roselli, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, 9500 Euclid Ave, Desk J4-1, Cleveland, OH 44195–5108; email: [email protected].

Ó 2017 by The Society of Thoracic Surgeons Published by Elsevier Inc.

The Supplemental Table can be viewed in the online version of this article [http://dx.doi. org/10.1016/j.athoracsur.2017.05.044] on http://www. annalsthoracicsurgery.org.

0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2017.05.044

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AFTAB ET AL DISTAL FENESTRATION FACILITATES EEC

fenestrated distal aorta [12, 13]. This study determined the safety and efficacy of this treatment strategy by evaluating early and late outcomes.

Ann Thorac Surg 2017;-:-–-

Table 1. Patient Characteristics and Preoperative Risk Factors in 56 Patients Who Underwent Stage 1 Elephant Trunk Procedure Value (n ¼ 56)

Characteristica

Patients and Methods Patient Characteristics From July 2007 to November 2014, 56 patients with thoracoabdominal dissection and false lumen aneurysm underwent the index procedure of distal descending open fenestration at the time of total arch and stage 1 ET repair. The index procedure was defined as stage 1 ET during which distal fenestration was performed. This technique was not used for acute dissection—all patients had chronic dissection at the time of operation. Median time from acute dissection to stage 1 ET repair was 30 months (interquartile range [IQR], 12 to 68 months). The shortest interval from acute dissection to the first-stage ET was 2 months in 2 patients who initially had acute type III dissection. Forty-nine patients (87.5%) underwent stage 2 EEC at a median interval of 2.2 months (IQR, 0.9 to 4.2 months) from the index operation. All patients had aneurysmal degeneration with chronic dissection at the time of operation. Of these, 38 patients (67.9%) had undergone previous acute type I dissection repair, 3 (5%) had chronic type I dissection, and 15 (26.8%) had chronic type III dissection. The preoperative mean maximum aortic diameter was 5.7 1.0 cm. Additional characteristics are listed in Table 1. The Cleveland Clinic Institutional Review Board approved this retrospective record review, and the need for informed consent was waived.

Operative Technique The operative technique has been described in detail in recent publications [12, 13]. Reoperative sternotomy was required in 40 patients (71.4%). Right axillary artery cannulation was performed using a side graft for inflow with hypothermic circulatory arrest and selective antegrade brain perfusion (SABP). Arch vessel reconstruction was performed first, followed by ET anastomosis and open fenestration of the distal descending aorta during the period of SABP. Aortotomy length for fenestration was approximately 6 to 8 cm (Fig 1). Mean duration of SABP was 57.3 22 minutes. During the stage 1 repair, 34 concomitant procedures were performed in 27 patients (48%). These included coronary bypass grafting in 8 (14%), aortic valve replacement in 7 (12.5%), aortic valve repair in 1 (2%), root remodeling in 3 (5.4%), modified Bentall procedure in 3 (5.4%), valve-sparing root replacement in 1 (2%), mitral valve repair in 1 (2%), atrial septal defect closure in 2 (3.5%), innominate aneurysm repair in 2 (3.5%), and pulmonary vein isolation in 3 (5.4%). The second-stage EEC was performed in 49 patients (87.5%) and urgently in 11 (22.4%). During the same hospitalization, 9 patients (18.4%) underwent EEC. The repairs in 3 patients were performed simultaneously with the first-stage ET, and 1 patient underwent second-stage

Age, y Male BMI, kg/m2 Family history of aortic pathology Connective tissue disease Hypertension History of stroke Type 2 diabetes COPD Hyperlipidemia Alcohol abuse Hepatic dysfunction Chronic renal insufficiency Renal failure requiring dialysis Atrial fibrillation Bicuspid aortic valve History of prior aortic/cardiac operation Aortic morphology Chronic thoracoabdominal aortic dissection with false lumen aneurysm Postacute type I repair Chronic type I dissection Chronic type III dissection a

57 11 47 (84) 27.5 5.8 13 (23.2) 3 (5.4) 54 (96.4) 5 (8.9) 3 (5.4) 8 (14.3) 39 (69.6) 3 (5.4) 3 (5.4) 4 (7.1) 2 (3.6) 9 (16.1) 3 (5.4) 44 (78.6) 56 (100) 38 (67.9) 3 (5) 15 (26.8)

Values are expressed as number (%) or mean SD.

BMI ¼ body mass index;

COPD ¼ chronic obstructive pulmonary disease.

completion within 24 hours of the index operation. Endovascular repair was extended to the celiac artery in 22 (45%), the distal descending aorta in 24 (49%), and the middle descending aorta in 3 (6%). A median of 2 stent graft devices (range, 1 to 5 devices) was used per patient. Preoperative planning and sizing were performed as described in previous reports [12, 13].

Follow-Up and Imaging All patients were monitored with computed tomography (CT), including noncontrast and arterial and delayed venous contrast phases through the chest, abdomen, and pelvis. Multidetector CT technology was used. The delayed-phase images were obtained 5 minutes after the contrast agent the administered. A low-osmolar contrast agent, Omnipaque 350 (GE Healthcare, Princeton, NJ), was used: 80 mL of contrast was used for image acquisition through advanced 256-slice CT scanners, and 120 mL was used in the standard scanner according to our institutional protocol. Imaging surveillance was performed at discharge, 3 months, and then annually thereafter. Images were analyzed using Aquarius three-dimensional reconstruction software (TeraRecon, San Mateo, CA) to assess for graft patency and morphology of the aneurysm and dissection. Compliance with follow-up imaging was 100% in surviving patients.



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Fig 1. This figure demonstrates the technique [12]. (A) Preoperative computed tomography (CT) shows the dissection (arrow). (B) Distal fenestration is made in the retrocardiac aorta during the first-stage elephant trunk. (C) Intraoperative image after flap resection to create a landing zone for the stent graft (arrow). (D) CT image after stage 1 shows absence of the dissection flap after resection (arrow). (E) The elephant trunk graft and descending aorta are shown after fenestration (arrow). (F) Endovascular elephant trunk completion with complete seal at the fenestrated segment. (G) Volume-rendered reconstruction CT image shows completed repair to the distal landing zone as marked by the surgical clips (arrow).

Of the 8 patients (12.5%) who underwent prophylactic ET, 7 are under surveillance for aneurysmal degeneration and have not yet required EEC. Compliance of this group is 86%, with 6 of 7 patients evaluated in the last 12 months.

Outcomes and Statistics Preoperative, operative, and outcomes variables were prospectively collected into our institutional Cardiovascular Information Registry. Imaging data were collected retrospectively [12]. Technical success after TEVAR was defined as successful delivery of stent graft into the proximal stage 1 ET graft with adequate seal in the distal fenestration landing zone without type I and III endoleaks, as confirmed by fluoroscopy, no intraoperative death, and survival within the first 24 hours. Because the total number of events was small, a descriptive analysis was performed. Categoric variables are summarized as number (%), and continuous variables are presented as median (IQR) or mean SD. Survival and freedom from intervention were determined using the Kaplan-Meier method.

Results Outcomes After Stage 1 ET and Fenestration In-hospital and 30-day mortality after the first stage was 1.8% (1 of 56 patients). In the patient who died, the

second-stage ET completion was performed during the same hospital admission because the patient had rapid growth with high risk of rupture. Temporary paraparesis developed in this patient postoperatively, which improved before discharge, but the patient suffered a massive pulmonary embolism and died on postoperative day 19. Other complications included subdural hematoma, 1 (1.8%); prolonged ventilation, 1 (1.8%); tracheostomy, 1 (1.8%); acute renal insufficiency, 2 (3.6%); and reoperation for bleeding, 5 (8.9%). Median lengths of stay were 4 days (IQR, 2 to 5.75 days) in the intensive care and 12 days (IQR 8 to 18 days) in the hospital. No patient was lost to follow-up.

Outcomes After Stage II EEC EEC was performed in 49 of 56 patients (87.5%) at a median interval of 2.2 months (IQR, 0.9 to 4.2 months) from the index operation. EEC was performed in a staged fashion during a separate hospitalization in 40 patients (81.6%). Technical success was achieved in all patients. No patients with staged repair experienced postoperative stroke, paraplegia, renal insufficiency, respiratory failure, or end-organ malperfusion. Four patients required additional procedures during the hospitalization, including hematoma evacuation and repair of common femoral artery, seroma drainage after carotidto-subclavian bypass, video-assisted thoracoscopic

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drainage of pleural effusion, and evacuation of hemothorax after repair of ruptured aneurysm. The median intensive care unit and hospital lengths of stay for EEC among 40 patients with separate hospitalization were 3 days (IQR, 2 to 4 days) and 7.5 days (IQR, 5 to 11.7) days, respectively.

grafted aorta in all 48 surviving patients. The determination of false lumen thrombosis was made based on the absence of contrast material in the false lumen in the delayed-phase images, acquired 5 minutes after the bolus injection. Imaging data were transferred to the workstation for further analysis.

Secondary Aortic Interventions, Endoleaks and False Lumen Thrombosis

Survival and Probability of Reintervention after EEC

Follow-up imaging analysis revealed shrinkage of the aneurysm sac in 33 of 48 surviving patients (69%). No aneurysm growth was observed in 13 (27%), and aortic growth was seen in just 2 patients (4%), and distal endoleak developed in these 2 patients. Mean reduction in the overall aortic diameter was 1 0.8 cm (Figs 2, 3) during a median follow-up of 3.3 months. Eight patients required 11 secondary aortic interventions. One patient required four reinterventions. He underwent TEVAR for a symptomatic aneurysm after acute-on-chronic dissection 9.6 months after EEC. Two months later, he underwent open thoracoabdominal aneurysm (TAAA) repair. Three months after the TAAA repair, he presented with infective endocarditis, root abscess eroding into the sternum and mediastinitis, requiring a third sternotomy and aortic root and ascending replacement with a homograft. During that hospitalization he underwent cardiopulmonary resuscitation for respiratory failure. A postresuscitation CT showed a new type III endoleak, necessitating an additional TEVAR. Unfortunately, this patient sustained an anoxic brain injury and died in a long-term acute care facility. Delayed secondary interventions are summarized in Table 2, and more details are described in Supplemental eTable 1. Follow-up imaging showed false lumen thrombosis and absence of retrograde false lumen flow in the stent

Median follow-up of patients who completed stage 2 EEC was 33.8 months (IQR, 15.6 to 58.4 months), and 30% were monitored for more than 4 years and 16% for more than 5 years. There were 6 late deaths. Mode of death was aspiration pneumonia and anoxic brain injury (4 months after EEC) in 1 patient, sepsis, coagulopathy (19 months after EEC) in another, and the cause was unknown in the other 4. Estimated survival after stage 1 EEC at 1, 3, 5, and 7 years was 96%, 92%, 82%, and 82%, respectively. Freedom from reintervention after EEC at 1, 3, 5, and 7 years was 92%, 81%, 77%, and 77%, respectively (Fig 4).

Comment First-stage ET and open distal aortic fenestration, followed by endovascular completion for extensive chronic aortic dissection, was first described in 24 patients in 2011 [12]. We have now performed 56 stage 1 procedures with distal open fenestration, of which 87.5% patients have completed the stage 2 EEC. One of seven prophylactic repairs was completed 6 years after the first stage, and none of the late deaths were from the prophylactic surveillance group. This update emphasizes the safety and effectiveness of this strategy to treat chronic dissection. Survivors of acute aortic dissections frequently require subsequent aortic interventions. Most patients in our study are survivors of DeBakey type I aortic dissection

Fig 2. (A) Preoperative computed tomography (CT) image of a patient with extensive aneurysm and chronic dissection. (B) Postoperative CT image shows complete repair after first-stage elephant trunk with distal fenestration and second-stage endovascular completion. There are no endoleaks, and the stent graft is patent and intact at 27 months of follow-up. (C) Volume-rendered reconstruction CT image shows intact repair. The surgical clips mark the location of distal fenestration.



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Fig 3. Preoperative (left column images), between stages (middle column), and postoperative (right column) contrast-enhanced computed tomography images demonstrate the progression of treatment of chronic dissection using the staged hybrid approach with elephant trunk and distal fenestration followed by TEVAR. (ET ¼ Elephant trunk; EEC ¼ endovascular elephant trunk completion; pre-op ¼ preoperative; post-op ¼ post-operative.)

who developed arch and descending aneurysm. Debakey type 1 dissection originally occurred in most patients in our study, and arch and descending aneurysms developed later in the course of their condition. Our group previously reported hospital mortality of 6.1% among 305 patients who underwent distal interventions after acute ascending dissection repair at a median interval of 3.8 years. The patients in this series had more rapid aortic growth, with a median time from initial dissection of 2.5 years. The probability of undergoing additional reintervention within 10 years was 38% [14]. Halstead and colleagues [15] reported their experience of 25 distal aortic reoperations in 16 of 179 patients (9%) after repair of an acute type A dissection over a median follow-up of 60 months. The median interval between acute aortic dissection to stage 1 distal aortic repair in our

study was 29.5 months (IQR, 14.7 to 48.5 months). These experiences highlight the importance of close follow-up and aggressive radiologic surveillance in patients with residual dissection even after reoperation. Staged repair for patients with multisegment aortic disease using an ET-first technique has become the preferred approach at most centers, with early mortality ranging from 2% to 12% and the incidence of stroke from 2.7% to 5.3% [5–9, 16]. Operative mortality and incidence of stroke in our series confirmed the safety of a staged approach in this select group of patients. Adding the distal aortic fenestration to stage 1 ET and total arch repair during the period of SABP did not increase risk compared with other contemporary series. Although exposure of the distal descending thoracic aorta through a median sternotomy can be technically challenging,

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Table 2. Patient Characteristics and Summary of Delayed Reinterventions Characteristics and Variablesa Age, y Male Interval from Stage 1 to stage 2, mo Stage 2 to reintervention, mo Indication for reinterventions Aneurysm degeneration/rapid growth Distal aortic rupture Type I endoleak Type III endoleak Infective endocarditis/fungemia Root abscess and mediastinitis Acute-on-chronic aortic dissection Total reinterventions, No. Delayed TEVAR extension TEVAR extension and FL embolization Open extent II TAAA repair Open extent IV TAAA repair Ascending and arch repair (homograft) Root and ascending repair (homograft) Follow-up after stage 1 completion, mo Follow-up after stage 2 completion, mo

Value (n ¼ 8) 56.8 13.8 8 (100) 2.2 (0.9–4.2) 15.9 (5.2–34.7) 4 1 2 1 1 1 1

(36.3) (9) (18) (9) (9) (9) (9) 11 4 (36.3) 3 (27.2) 1 (9.1) 1 (9.1) 1 (9.1) 1 (9.1) 42.6 27.4 36.6 (20–71.4)

Variables are expressed as number (%), mean SD, or median (interquartile range).

a

FL ¼ false lumen; TAAA ¼ thoracoabdominal aortic aneurysm; TEVAR ¼ thoracic endovascular aortic repair.

limiting this part of the procedure to the anterior wall of the chronically dissected aorta makes it safe and reproducible. A well-described limitation of the staged ET approach is the risk of rupture between stages, and a significant number of patients do not return for stage 2 completion. In some series, only 42% to 57% of patients completed the stage 2 procedure [5–7]. This is particularly important because 5-year survival among patients without stage 2 completion is reported to be as low as 34% compared with 75% at 3 years after the stage 2 completion [5]. Etz and colleagues [16] reported that among 18 of 139 patients who did not undergo planned completion, 89% (16 of 18) died within a median interval of 5 months from stage 1. Reasons for the significant number of patients not completing the second stage include complications after the first procedure making them unsuitable, patient choice to defer because of the magnitude of two operations, or the surgeon’s choice to perform the first-stage procedure as a prophylactic operation [17]. To overcome these limitations, Kouchoukos and colleagues [18] described a single-stage strategy in patients with extensive disease by repairing both the proximal and distal thoracic aorta through a clamshell incision. They reported excellent results, with early mortality of 2.9% and stroke of 1.5%. Nonetheless, morbidity was

Fig 4. The Kaplan-Meier method shows (A) estimated survival after total arch replacement with stage 1 elephant trunk and distal descending thoracic aortic fenestration is 96%, 92%, 82%, and 82%, respectively, at 1, 3, 5, and 7 years, and (B) estimated freedom from secondary reintervention after endovascular elephant trunk completion is 90%, 78%, 74%, and 74%, respectively, at 1, 3, 5, and 7 years.

significant, with 7.5% requiring hemodialysis, respiratory failure occurring in 45%, and 15% requiring tracheostomy [18]. Alternatively, the use of stent grafts as part of the repair may reduce the burden on the patient. Conventional second-stage open distal aortic reconstruction also carries significant risk of operative mortality (range, 4% to 9.7%) and paraplegia (range, 0% to 3%) [5, 6]. Greenberg and colleagues [10] reported the initial experience of EEC in 22 patients with no operative deaths, paraplegia, or stroke. Transient paraparesis occurred in 3 patients in that series, and all 3 had a history of abdominal aortic repair [10]. Risk of paraplegia is more strongly associated with the extent of the aortic repair than with the approach. By performing the second-stage completion repair endovascularly, morbidity may be reduced and the likelihood of returning for the second stage is increased [11]. In the current series, all patients who required stage 2 completion underwent a timely EEC. Depending on the length of coverage necessary, another option is to perform the operation as a single-stage frozen ET trunk procedure. The use of a stented ET offers the additional benefit of avoiding ET collapse in the true lumen.


Secondary Delayed Aortic Interventions Patients with aortic dissection in the untreated aorta are vulnerable to further aortic degeneration and additional reinterventions. Although the thoracic aorta was initially successfully treated with the two-stage approach in all patients, 8 patients required 11 delayed aortic interventions. All but one of these involved the aorta beyond the repaired segment or infection of a prosthesis. Seven of these interventions were addressed with endovascular procedures, including TEVAR extension or false lumen embolization, or both. We previously reported the use of this adjunctive technique to promote false lumen thrombosis and aortic remodeling after stent grafting the true lumen in patients with chronic dissection [19]. TEVAR in the true lumen alone is often not sufficient to promote false lumen thrombosis and aortic reverse remodeling. Despite healing in the treated segment, the false lumen has continued to grow distally in some patients. Fortunately, it was uncommon, but only 2 patients required additional open repair. We have noted that in the group with delayed reintervention, half of the patients (4 of 8) had a distal descending thoracic aortic diameter at the level of diaphragm ranging from 4.1 to 5.3 cm. Although aortoplasty is performed as part of the distal aortic fenestration, 3 of these patients required distal TEVAR extension, and 1 underwent open TAAA repair. The aorta at the level of the diaphragm being greater than 42 mm may predict late failure. In both of our previously published experiences of treating chronic dissection (1 open and 1 endovascularly), we found that the aortic diameter at the level of the celiac trunk was the strongest predictor for the composite outcome of death or reintervention [4, 20]. Choosing the level of fenestration for creating a distal aortic landing zone is critical. Ideally, it should be 4 cm or less on the centerline of flow. We are now more stringent in patient selection for distal aortic fenestration, based on the overall diameter of the distal landing zone, to avoid the risk of further aortic degeneration. Two of the delayed reinterventions were because of infective complications, including one of the prosthetic valve and the other infection affecting the graft. This complication has been described as an independent risk factor for death after aortic reoperations, but exposure to this potential risk may be inevitable [21]. During long-term follow-up, the ability to induce reverse aortic remodeling or halt the aortic growth in 94% of patients provides proof of the principle that TEVAR in combination with strategies to exclude flow into false lumen can reliably protect the treated segment of aorta from aneurysmal degeneration and induce aortic remodeling. The surgical morbidity is probably reduced by avoiding a thoracotomy or thoracoabdominal incision. After our initial report, other groups have also adopted this strategy and reported a few cases with open or endovascular fenestration to create adequate distal landing zones for subsequent endovascular repair [22, 23]. Based on the principles demonstrated during this surgical experience, we have also been using a balloon


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fracture fenestration technique to optimize stent graft expansion and promote earlier remodeling by creating a distal landing zone after ballooning. As we have gained more experience with this technique and other endovascular adjuncts, we believe that therapies should be tailored to the individual and his or her disease. When the patients reach a sufficient number, a fair comparison with a similar population will provide further information to refine patient selection and the benefits of this therapy. Other important considerations are the patient’s age, comorbidities, and the presence of a connective tissue disorder, along with the surgeon’s experience [24]. A limitation of our report is the inherent inadequacy of the contrast-enhanced CT angiography (CTA) in the precise determination of false lumen thrombosis. Clough and colleagues [25] have reported that the extent of false lumen thrombosis measured by magnetic resonance imaging (MRI) using blood pooled agents underestimates the thrombus volume by five to six times compared with the techniques using first-pass CTA and MRI. This is particularly important for the studies where the extent of false lumen thrombosis is the primary end point. In our study, although the false lumen thrombosis was determined based on gated multiphase contrast-enhanced CTA with the delayed-phase stent protocol, we also noted that the aneurysm sac shrunk in 67% of the patients. However, despite the technical limitation of contrast-enhanced CTA in overestimating the volume of false lumen thrombosis, this study provides proof of the concept that the open aortic fenestration to create a distal landing zone during stage 1 ET facilitates endovascular completion and promotes reverse aortic remodeling. Our long-term experience shows that the technique of first-stage ET along with distal aortic fenestration, followed by EEC, is safe, effective, and durable. We recommend this therapy for patients with suitable anatomy with extensive thoracic aortic aneurysm secondary to chronic dissection. This study was supported in part by Judith and John S. Chew and the Warden Foundation. The authors thank Brian Kohlbacher for assistance with the illustrations and Hajra F. Khan, BS, JD, for providing editorial support.

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5. Svensson LG, Kim KH, Blackstone EH, et al. Elephant trunk procedure: newer indications and uses. Ann Thorac Surg 2004;78:109–16; discussion 109–16. 6. Safi HJ, Miller CC, 3rd, Estrera AL, et al. Staged repair of extensive aortic aneurysms: long-term experience with the elephant trunk technique. Ann Surg 2004;240:677–84; discussion 684–5. 7. LeMaire SA, Carter SA, Coselli JS. The elephant trunk technique for staged repair of complex aneurysms of the entire thoracic aorta. Ann Thorac Surg 2006;81:1561–9; discussion 1569. 8. Svensson LG, Rushing GD, Valenzuela ES, et al. Modifications, classification, and outcomes of elephant-trunk procedures. Ann Thorac Surg 2013;96:548–58. 9. Schepens MA, Dossche KM, Morshuis WJ, van den Barselaar PJ, Heijmen RH, Vermeulen FE. The elephant trunk technique: operative results in 100 consecutive patients. Eur J Cardiothorac Surg 2002;21:276–81. 10. Greenberg RK, Haddad F, Svensson L, et al. Hybrid approaches to thoracic aortic aneurysms: the role of endovascular elephant trunk completion. Circulation 2005;112: 2619–26. 11. Roselli EE, Subramanian S, Sun Z, et al. Endovascular versus open elephant trunk completion for extensive aortic disease. J Thorac Cardiovasc Surg 2013;146:1408–16; discussion 1416–7. 12. Roselli EE, Sepulveda E, Pujara AC, Idrees J, Nowicki E. Distal landing zone open fenestration facilitates endovascular elephant trunk completion and false lumen thrombosis. Ann Thorac Surg 2011;92:2078–84. 13. Roselli EE. Optimization of distal landing zone for TEVAR in chronic dissection. Ann Cardiothorac Surg 2014;3:329–32. 14. Roselli EE, Loor G, He J, et al. Distal aortic interventions after repair of ascending dissection: the argument for a more aggressive approach. J Thorac Cardiovasc Surg 2015;149(2 Suppl): S117–24.e3. 15. Halstead JC, Meier M, Etz C, Spielvogel D, et al. The fate of the distal aorta after repair of acute type A aortic dissection. J Thorac Cardiovasc Surg 2007;133:127–35.


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DISCUSSION DR THOMAS E. MACGILLIVRAY (Boston, MA): That was really an excellent presentation of excellent data. Can you talk a little bit about the patient selection and what you have learned over the years? Who are the most appropriate patients for open fenestration, and on which patients is open fenestration best avoided? Where exactly on the aortic is the best site to perform open fenestration? DR AFTAB: This is a great question. Thank you very much for your comment. Essentially, we learned over the course of the last 7 years which patients are more suitable for this procedure. As I alluded to earlier, 2 of our patients required open thoracoabdominal aortic aneurysm repair, and both of these patients had a distal aorta that was about 4 cm in diameter. Although we performed the fenestration, and we closed the aorta by buttressing with the bovine pericardium, we thought that that would be enough of a landing zone, and it provided a very good landing zone initially. But subsequently, these patients required reintervention. Also, the procedure itself is not a very simple procedure. But I consider it is worth it performing the procedure on patients who have an adequate landing zone or who have an aorta which is at least 4 cm or smaller than that. Similarly, we have to keep in consideration the age of the patient, the other comorbidities, and the connective tissue

disorder patients. These are the patients who, if you perform this procedure, it might initially facilitate or help us in delaying the open repair. But those patients might not be the very suitable candidates for this procedure. DR ROSELLI: And if I could add to that, I agree with Mo’s assessment. We are only treating the thoracic aorta in these folks. Although I have had a couple patients where we extended the incision to an upper laparotomy, and I have mostly been able to do the open fenestration to a point right above the origin of the celiac trunk through a sternotomy. It is a tough exposure. So when the patient is really obese, we might reconsider using this approach. What I think is one of the most important lessons about this experience is the proof of principle about the fundamentals of how we are treating chronic dissections. Specifically, what I mean is that getting the stent graft to oppose adventitia circumferentially, we see the aorta reverse remodel. This approach negates retrograde false lumen perfusion as a problem. I would also like to add that although we still do these procedures, I do them less often, because we now have learned to use some endovascular techniques to address the false lumen such as ballooning the flap or putting occlusive devices into the false lumen.