Endovascular Salvage After False Lumen Misdeployment of Thoracic Endovascular Aortic Repair or the Frozen Elephant Trunk in Aortic Dissection: A Case Report of Two Patients

Abstract

Thoracic endovascular aortic repair (TEVAR) and the frozen elephant trunk (FET) are well-established treatment options for aortic dissection (AD). Inadvertent misdeployment of a TEVAR stent graft or FET into the false lumen (FL) can lead to serious complications. We report two cases of FL misdeployment. First, a 68-year-old female with acute Stanford type B AD underwent TEVAR; follow-up computed tomography angiography (CTA) revealed stent-graft misdeployment into the FL. Second, a 44-year-old female with Marfan syndrome, who had undergone supracoronary ascending aortic grafting for type A AD at 25 years of age, underwent urgent FET 19 years later for a symptomatic dissecting arch aneurysm; follow-up CTA confirmed misdeployment into the FL. In both cases, endovascular rescue was performed with fenestration of the intimal flap and additional stent-graft deployment to reroute flow into the true lumen. Misdeployment of TEVAR or FET into the FL is catastrophic but treatable with rapid diagnosis and timely intervention.

INTRODUCTION

Aortic dissection (AD) is a life-threatening condition characterized by a tear in the aortic wall with subsequent false lumen (FL) formation, which weakens the aortic wall and increases the risk of rupture. In addition, it can compromise blood flow to the target organs, resulting in severe ischemia and potential organ dysfunction.

Several techniques are used for AD management depending on its type, including supracoronary ascending aortic replacement (interposition grafting) with or without aortic root replacement, aortic arch repair with a frozen elephant trunk (FET), and thoracic endovascular aortic repair (TEVAR).

Regardless of the procedure, the goal is to seal the primary entry tear and promote positive aortic remodeling by reducing pressure in the FL. A prerequisite for achieving this is deployment of the FET or TEVAR into the true lumen (TL). Herein, we present two clinical scenarios of FET/TEVAR misdeployment into the FL and how they were managed. The study protocol complied with the ethical standards for human experimentation and the Declaration of Helsinki. Informed consent was obtained from all patients.

CASE

1) Case 1

Patient A was a 68-year-old female with acute AD (Stanford classification, type B). She was treated for arterial hypertension, hypercholesterolemia, and hypothyroidism. The interval between symptom onset and admission to our hospital was 2 days.

Initial computed tomography angiography (CTA) revealed Stanford type B AD (Fig. 1A) with an entry tear located approximately 4 cm distal to the origin of the left subclavian artery. An intramural hematoma was also documented on the initial CTA, located between the origin of the left subclavian artery and the entry tear of the AD. The re-entry tear was located in the left common iliac artery. The celiac trunk, superior mesenteric artery, and right renal artery originated from the TL, whereas the left renal artery originated from the FL.

Fig. 1.

Angiography and CTA of the aorta in Patient A obtained before, during, and after the initial TEVAR procedure. (A) Preprocedural CTA showed Stanford type B aortic dissection. (B) Intraoperative abdominal aortic angiography showed only arterial branches originating from the TL, suggesting that the pigtail catheter was positioned in the TL. (C) Final thoracic aortic angiography after stent-graft deployment; abdominal aortic angiography was not performed at the end of the procedure. (D) Postprocedural CTA demonstrated inadvertent stent-graft deployment into the FL with full collapse of the TL. CTA, computed tomographic angiography; TEVAR, thoracic endovascular aortic repair; TL, true lumen; FL, false lumen; SMA, superior mesenteric artery; RRA, right renal artery; SA, splenic artery; CHA, common hepatic artery.

Due to persistent pain and refractory arterial hypertension despite maximal conservative pharmacological treatment, a TEVAR procedure was performed. A stent graft (Valiant^TM Captivia^TM VAMF3838C120TE, Medtronic) was deployed in the descending aorta (proximal sealing in Zone 3, immediately distal to the origin of the left subclavian artery). Fig. 1B, C show the angiographic results of the initial TEVAR procedure.

However, a significant elevation of serum creatinine and liver enzymes occurred one day after the initial TEVAR procedure; therefore, CTA was performed, which documented full collapse of the TL due to deployment of the distal part of stent graft into the FL (Fig. 1D). Emergency reintervention was indicated.

The TL was first cannulated, and diagnostic angiography using a pigtail catheter was performed to verify the correct position of the catheter in the TL (Fig. 2A). Subsequently, the dissection membrane was fenestrated using a re-entry catheter (OUTBACK Elite Re-Entry Catheter, Cordis) (Fig. 2B). A connection was achieved between the TL and FL. After enlargement of the intimal fenestration by balloon angioplasty, first using a Passeo-18 PTA catheter (4×40 mm, Biotronik) followed by an Admiral Xtreme PTA catheter (12×40 mm, Medtronic), an additional stent graft (Valiant^TM Captivia^TM VAMC4238C150TE, Medtronic) was deployed. The FL and TL were reconnected, and blood flow was rerouted from the FL to the TL. This allowed opening of the TL and reperfusion of the visceral organs (Fig. 2C). However, rerouting the blood flow also caused occlusion of the left renal artery. Because of deteriorating renal function, cannulation of the left renal artery with subsequent stent implantation (Dynamic Renal; 7×19 and 7×12 mm, Biotronik) was performed.

Fig. 2.

Angiography and CTA of aorta in the Patient A obtained during and after the bailout TEVAR procedure. (A) Intraoperative angiography demonstrated the TL, whereas the initially deployed stent graft was located in the FL. (B) Fenestration of the intimal membrane was performed using a re-entry catheter (OUTBACK, Cordis), and passage from the TL to the FL (into the misdeployed stent graft) was successfully achieved using a guidewire. (C) Final aortic angiography after intimal fenestration and deployment of an additional stent graft. (D) Postprocedural CTA showed TL–FL communication with rerouting of blood flow from the FL to the TL, remodeling of the TL, and partial collapse of the FL. CTA, computed tomographic angiography; TEVAR, thoracic endovascular aortic repair; TL, true lumen; FL, false lumen; SMA, superior mesenteric artery; LRA, left renal artery.

The duration of the first procedure was 60 minutes, and the fluoroscopic time was 3 minutes 42 seconds, with an overall dose of 814 mGy. The duration of the second rescue procedure was 150 minutes, and the fluoroscopic time was 25 minutes 7 seconds, with an overall dose of 2,482 mGy. CTA of the aorta was performed one day later. Positive remodelling of the TL with good perfusion of the visceral organs was verified (Fig. 2D).

She was readmitted to our hospital’s emergency department 2 months after discharge due to sudden-onset severe pain above the sternum and between the scapulae, dyspnea, and pain and numbness in both upper limbs. CTA revealed retrograde dissection of the aortic arch. Therefore, urgent aortic arch replacement was performed. The patient underwent clinical follow-up and CTA 6 months and 1.5 years after the surgery and remained clinically stable without relevant symptoms. CTA confirmed complete thrombosis of the FL of the thoracic AD and adequate perfusion of the target abdominal organs. The abdominal aorta was not dilated.

2) Case 2

Patient B was a 44-year-old female with confirmed Marfan syndrome who had undergone supracoronary interposition grafting of the ascending aorta at the age of 25 years (in 2006) for type A AD. The remaining dissected segments (the aortic arch, descending thoracic aorta, and abdominal aorta) were managed with observation and conservative treatment; however, she was lost to surveillance and follow-up after the initial operation.

Nineteen years later, she was urgently evaluated in the emergency department at our institution because of sudden, sharp, severe pain over the sternum and between the scapulae. She developed dysphonia and was anxious and distressed. CTA was performed immediately and identified a symptomatic dissecting aneurysm of the aortic arch, with a maximum diameter of 58 mm, arising from aneurysmal degeneration of the chronic dissection (Fig. 3A). Chronic dissection of the descending thoracic and abdominal aorta was confirmed (Fig. 3B, C). There were no other diseases in her personal history. The patient was admitted to the intensive care unit. Given the suspected high risk of aortic rupture, an FET procedure was indicated and subsequently performed using a Thoraflex^TM Hybrid 26/28 mm (Terumo) device. Approximately 60 minutes later, a planned CTA revealed misdeployment of the distal part of the FET device into the FL (Fig. 3D).

Fig. 3.

CTA of the aorta in the Patient B obtained before and after the initial FET procedure. (A) Preprocedural CTA showed chronic type A aortic dissection with a dissecting aneurysm of the aortic arch (maximum diameter, 58 mm). (B) Axial CTA showed an intimal tear measuring 15 mm at the level of sixth and seventh thoracic vertebrae. (C) Oblique CTA showed an intimal tear measuring 42 mm in length at the same level. (D) Postprocedural CTA demonstrated inadvertent deployment of the stented portion of the Thoraflex Hybrid^TM (Terumo) device into the FL with complete collapse of TL. CTA, computed tomographic angiography; FET, frozen elephant trunk; TL, true lumen; FL, false lumen.

The patient was urgently transferred to the catheterization laboratory for an endovascular rescue procedure. The TL was successfully cannulated, and subsequent diagnostic angiography using a Berenstein catheter confirmed correct positioning in the TL. The natural tear in the intimal membrane was then cannulated using a Radifocus Guide Wire M Stiff Type (Terumo) and TEMPO Berenstein 5-Fr catheter (Cordis) (Fig. 4A, B). Finally, two stent grafts, Zenith Alpha ZTA-P-28-155 (Cook Medical) and Valiant^TM Captivia^TM VAMF32328C150TE (Medtronic), were deployed, successfully rerouting blood flow from the FL to the TL (Fig. 4C).

Fig. 4.

Angiography and CTA of aorta in the Patient B obtained during and after the bailout TEVAR procedure. (A) Intraoperative angiography showed the localization and morphology of the TL, whereas the stented portion of the Thoraflex Hybrid^TM (Terumo) device was located in the FL. (B) Passage from the TL to the FL and into FET was achieved by cannulation of a natural intimal tear using a TEMPO Berenstein 5-Fr catheter (Cordis) and a stiff guidewire. (C) Final aortic angiography after deployment of additional stent grafts into the misdeployed FET device. (D) Postprocedural CTA demonstrated TL–FL connection with rerouting of blood flow from the FL to the TL, remodeling of the TL, and partial collapse of the FL. CTA, computed tomographic angiography; TEVAR, thoracic endovascular aortic repair; FET, frozen elephant trunk; TL, true lumen; FL, false lumen; SMA, superior mesenteric artery.

The rescue TEVAR procedure duration was 75 minutes, and fluoroscopic time was 6 minutes 24 seconds, with an overall dose of 250 mGy. CTA performed two days later confirmed positive remodelling of the TL with good perfusion of the visceral organs (Fig. 4D). The patient attended two follow-up visits and reported no complaints or pain. Follow-up CTA showed almost complete thrombosis of the FL in the descending thoracic aorta. There were no clinical or imaging signs of malperfusion of the target abdominal organ. The maximum transverse diameter of the abdominal aorta was 36 mm, and the chronic dissecting abdominal aortic aneurysm showed no tendency to enlarge.

The impact of bailout procedure delay on changes in selected laboratory parameters over time in patients A and B is shown in Fig. 5.

Fig. 5.

Laboratory parameter concentrations over time were recorded and graphically presented. Bailout procedure delayed the changes in the concentration of selected laboratory parameters over time in Patients A and B.

DISCUSSION

Accidental deployment of FET or TEVAR stent graft into the FL of an AD is a rare but serious condition. When the main blood flow is directed into the FL, FL pressurization increases and can result in compression and collapse of the TL. The consequences can include extension of the intimal tear, FL rupture, and inadequate perfusion of the target organs.

In this report, we describe two cases of FL misdeployment associated with visceral malperfusion and organ dysfunction (renal failure and bowel and liver ischemia). Case 1 involved inadvertent TEVAR misdeployment in acute complicated Stanford type B AD, whereas Case 2 involved FET misdeployment into the FL in a patient with Marfan syndrome and a symptomatic dissecting aneurysm of the aortic arch. Both cases were managed with endovascular rescue: fenestration of the intimal membrane using a re-entry catheter (Case 1) and cannulation of a pre-existing intimal tear with a stiff wire (Case 2), followed by additional stent-graft deployment to reroute blood flow from the FL into the TL.

Endovascular stent-graft implantation in a 44-year-old patient with Marfan syndrome may be considered controversial. However, TEVAR was used as a bailout strategy rather than definitive treatment. At the time of the FET procedure, the maximum diameter of the descending thoracic and abdominal aorta was 38 mm; therefore, additional open repair was not indicated. Nevertheless, if new aortic symptoms develop or progressive dilatation occurs in these segments with formation of a dissecting aneurysm, comprehensive surgical treatment should be considered.

Both patients survived after misdeployment and the subsequent rescue procedures; however, recovery was substantially longer and more complicated in Case 1 than in Case 2 (Fig. 5). The most likely explanation is the longer delay between misdeployment and diagnosis in Case 1, resulting in more advanced ischemic injury to the target organs. This underscores the importance of rapid recognition and timely intervention.

Misdeployment of TEVAR or FET into the FL has rarely been reported in the literature. Table 1, 2 summarize selected reports of TEVAR or FET misdeployment into the FL published over the last 15 years. Five studies [1-5] reported TEVAR misdeployment into the FL. In one report, the misdeployed stent graft was surgically removed, followed by aortic reconstruction [1], whereas the remaining studies described endovascular management. FET misdeployment into the FL has been reported more frequently [4,6-12], likely because distal FET deployment is often performed under limited direct visualization and the descending thoracic aorta lies deep within the chest cavity. Tamai et al. [9] managed mistaken FET deployment by implanting additional FET into the TL under intraoperative transesophageal echocardiography guidance. Most other reports achieved correction with endovascular techniques [4,6-8,10-12]. The favorable survival of both patients in the present report is reassuring, although this complication clearly increases morbidity.

Table 1.

Published reports of inadvertent TEVAR deployment into the FL of aortic dissection

No.	Study	Type of AD	Initial procedure	Remedial measure
1	Follis et al. [1], 2010	B	TEVAR	Surgical removal of misdeployed stent graft+surgical reconstruction of entire aorta
2	Ma et al. [2], 2016	B	TEVAR	Fenestration of IM using re-entry catheter (OUTBACK) and additional stent graft
3	Han et al. [3], 2016	B	TEVAR	Fenestration of IM using wire and support catheter, followed by additional stent graft
4	DiBartolomeo et al. [4], 2024	B	TEVAR	Fenestration of IM using laser and additional stent graft
5	Zhu et al. [5], 2024	B	TEVAR	Cannulation of natural tear in IM and additional stent graft

TEVAR, thoracic endovascular aortic repair; FL, false lumen; AD, aortic dissection; IM, intimal membrane.

Table 2.

Published reports of inadvertent FET deployment into the FL in aortic dissection

No.	Study	Type of AD	Initial procedure	Remedial measure
1	Plotkin et al. [11], 2019	A	FET	Fenestration of IM using radio-frequency wire and additional TEVAR
2	Kawashima et al. [6], 2020	A	Ascending aorta replacement and FET	Fenestration of IM using re-entry catheter and additional TEVAR
3	Tamai et al. [9], 2020	A	FET	Surgical revision and additional FET
4	Reid et al. [7], 2021	A	Ascending aorta replacement and modified FET	Cannulation of natural tear in IM and additional TEVAR
5	Takagi et al. [10], 2021	A	FET	Fenestration of IM using stiff wire and additional TEVAR
6	Buia et al. [8], 2022	A	Bentall procedure in the past for acute AD, followed by FET for chronic AD	Cannulation of natural tear in IM and additional TEVAR
7	DiBartolomeo et al. [4], 2024	A	FET	Laser fenestration of IM and additional TEVAR
8	Witcher et al. [12], 2023	A	FET	Fenestration of IM using needle-containing catheter (Rosh–Uchida) and additional TEVAR

FET, frozen elephant trunk; FL, false lumen; AD, aortic dissection; IM, intimal membrane; TEVAR, thoracic endovascular aortic repair.

The key principle of endovascular management of FL misdeployment is to create a TL–FL connection and then establish TL-directed flow. This can be achieved by cannulation of a natural intimal tear (flap) [5,7,8] or by fenestration. Various fenestration techniques have been reported, including stiff-wire fenestration [2,3,10], radiofrequency wire (e.g., PowerWire) [11], laser (e.g., Turbo-Elite laser catheter) [4], and re-entry (or crossing) catheters (e.g., OUTBACK) [2,6]. After successful TL–FL communication, balloon dilatation of the fenestration or tear is typically performed, followed by deployment of an additional stent graft to reroute flow from the FL into the TL.

Because the success of TEVAR or FET depends on accurate placement within the TL, meticulous review and analysis of preprocedural CTA should be standard practice, particularly before TEVAR. Preprocedural CTA allows the physician to define the locations of intimal tears and clarifies the relationship between each lumen and branch vessels (renal, mesenteric, and celiac). During TEVAR, targeted angiography can assist in confirming the lumen in which the catheter and guidewire are positioned: branch vessels arising from the lumen containing the angiographic catheter opacify more clearly, whereas branches from the opposite lumen may show poor or absent filling. This is important because guidewires and diagnostic catheters may inadvertently traverse between the TL and FL through natural tears in the intimal membrane during dissection navigation.

In Patient A, factors potentially contributing to TEVAR misdeployment included operator experience and off-hours timing. Selective targeted angiography during TEVAR identified all branches of the abdominal aorta arising from the TL and branches of the aortic arch (Fig. 1B), which may have led to the assumption that the guidewire remained in the TL along the entire dissection. Consequently, the final angiography after stent-graft deployment was performed only in the thoracic aorta, without abdominal aortic angiography. Consistent angiography extending to the abdominal aorta might have revealed impaired filling of visceral branches and prompted earlier recognition of misdeployment. It is likely that the guidewire passed from the TL to the FL through a natural tear in the descending thoracic aorta before deployment.

In Patient B, the distal stented portion of the Thoraflex Hybrid was deployed into the FL, likely related to patient-specific anatomy and technical factors. A large intimal tear (15 mm in width and 42 mm in length) was present in the descending thoracic aorta at the level of the T6–T7 (Fig. 3B, C). The caudal end of the stented portion was positioned at this level. Given the large size of the intimal tear, the stented segment may have migrated from the TL into the FL through the tear. Another possibility is inadvertent guidewire passage from the TL to the FL through a large tear before deployment of the Thoraflex Hybrid device. Because the tear was large and identified on preprocedural CTA, additional intraoperative confirmation of guidewire position could have been considered. Intraoperative transesophageal echocardiography or intravascular ultrasound can help verify TL positioning during TEVAR or FET and may reduce the risk of misdeployment; however, these techniques are not routinely used for this purpose at our institution.

In summary, inadvertent FL deployment of TEVAR or FET is rare but potentially catastrophic. Prompt diagnosis and timely endovascular rescue can restore TL-directed flow and mitigate malperfusion.

Funding Statement

FUNDING None.