Frozen Leaflet During Transcatheter Balloon-Expandable Aortic Valve Implantation

Abstract

Background

The occurrence of frozen or stuck leaflet during transcatheter aortic valve implantation (TAVI) is a rare but potentially fatal complication.

Case Summary

An 83-year-old man was referred to an Italian Cardiology Unit for symptomatic severe aortic stenosis. The patient underwent transfemoral TAVI with a 26-mm Myval balloon-expandable valve. After deployment, severe aortic regurgitation was revealed by aortography. Transesophageal echocardiography showed hypomobility of one of the 3 leaflets. Unsuccessful attempts to restore mobility were made using a pigtail catheter and performing postdilation, requiring a valve-in-valve procedure, without any hemodynamic compromise.

Discussion

Anatomical and procedural factors may be responsible for frozen leaflet during TAVI, predominantly reported with balloon-expandable valves. Transesophageal echocardiography enables rapid recognition, while angiography alone may be insufficient. A prompt hemodynamic support could be also required to avoid adverse procedural outcomes.

Conclusions

A structured intervention algorithm and timely multidisciplinary involvement is essential to optimize outcomes in this high-risk situation.

Visual Summary

The occurrence of frozen leaflet, also known as stuck leaflet, after transcatheter aortic valve implantation (TAVI) is a rare but potentially fatal complication. It consists of hypomobility or immobility of one or more of the 3 prosthesis leaflets, leading to massive intra-aortic regurgitation with possible subsequent hemodynamic instability and cardiogenic shock, often requiring mechanical circulatory support. Its reported incidence ranges between 0.1% and 0.4%.^1,2 The first case was reported in 2011 by Al-Attar et al³, describing an immediately post-implantation severe intravalvular leak, observed on transesophageal echocardiogram (TEE), due to an immobile cusp associated with left ventricular distension and cardiovascular collapse after transapical TAVI with a 23-mm Edwards SAPIEN valve. The case resulted in a fatal outcome. Subsequently, in 2012, Agostoni et al⁴ described a new case of frozen leaflet after TAVI, promptly resolved using intracardiac echocardiography and the additional implantation of a valve-in-valve (ViV) prosthesis. A handful of further cases have been reported in the literature,5, 6, 7 including 2 involving all 3 leaflets after balloon-expandable valve implantation,^8,9 and other 2 cases following self-expandable valve implantation.^10,11 Timely recognition of this complication is crucial in order to prevent hemodynamic instability and adopt appropriate solutions without any delay. Given its potential to precipitate catastrophic hemodynamic collapse, prompt adoption of appropriate rescue strategies is paramount for the interventional cardiologist. In the present case report, we describe and analyze a case of intraprocedural frozen leaflet occurring during TAVI with a balloon-expandable valve.

Take-Home Messages

• •Frozen or stuck leaflet represents a rare but life-threatening complication that should be considered when severe aortic regurgitation develops following transcatheter aortic valve implantation.
• •Transesophageal echocardiography imaging support can facilitate the rapid identification of mechanism responsible for severe aortic regurgitation.
• •Following a structured intervention algorithm and timely multidisciplinary involvement is essential to prevent hemodynamic deterioration.

Case Presentation

History of presentation and past medical history

An 83-year-old man, symptomatic for exertional dyspnea, was referred to the Cardiology Unit of Santa Maria delle Croci Hospital in Ravenna, Italy, for severe aortic stenosis, for which he was being followed up with echocardiographic monitoring. He was a former smoker and had a history of type 2 diabetes, arterial hypertension, and dyslipidemia. He also suffered from chronic kidney disease and hypothyroidism, treated with supplemental pharmacological therapy. His history was positive for a previous episode of paroxysmal atrial fibrillation and multiple myeloma, currently treated with lenalidomide under hematologic follow-up. His weight was 71 kg, height 170 cm, and body mass index 24.6.

Investigations

Transthoracic echocardiography revealed a normal left ventricular ejection fraction (65%), severe hypertrophy with a predominantly concentric pattern, mild left atrial dilatation, and normal aortic root dimensions. Severe calcification of the aortic valve apparatus was noted, with an aortic valve area of 0.87 cm², a peak velocity of 4.2 m/s, and maximum and mean transvalvular gradients of 65 and 43 mm Hg, respectively, with mild aortic regurgitation (Figure 1A). Coronary angiography demonstrated diffuse atheromasia without significant obstructive coronary lesions (Figure 1B). Computed tomography showed an aortic annulus area of 644.6 mm², a perimeter of 91 mm, and minimum and maximum diameters of 26.1 mm and 32.5 mm, respectively. The coronary heights were 13.7 mm for the left coronary artery and 24.1 mm for the right coronary artery (Figure 2). The EuroSCORE II was 2.48%.

Figure 1.

Preoperative Assessment for the Transcatheter Aortic Valve Implantation Procedure

(A) Preoperative transthoracic echocardiography showing severe aortic stenosis. (B) Coronary angiography revealed no significant coronary artery stenosis.

Figure 2.

Computed Tomography-Derived Reconstruction and Measurements for the Purpose of Transcatheter Aortic Valve Implantation

Management

After multidisciplinary discussion within the heart team and considering the patient's age and comorbidities, the decision was made to proceed with TAVI. The procedure was planned via a right transfemoral approach and secondary left transradial approach under deep analgosedation. After placement of a super-stiff wire in the left ventricle, balloon predilation was performed using a 23 × 40-mm balloon (Figure 3A). Following deployment of a 26-mm balloon-expandable Myval Octapro valve under rapid percutaneous pacing (Figure 3B), severe intraprosthetic regurgitation was detected by angiography (Sellers' grade 3) (Figure 3C). TEE revealed reduced motion of the prosthetic leaflet corresponding to the right cusp, consistent with frozen leaflet, associated with severe intraprosthetic regurgitation (Figure 4). Hemodynamic parameters remained stable without the need for circulatory support or inotropic agents. First, manipulation of the implanted valve was attempted using the pigtail in an effort to restore the normal motion of the immobilized leaflet. Second, prompt postdilation with a 25-mm balloon was performed, without improvement (Figure 3D). Therefore, the decision was made to implant a second valve. A ViV procedure was then performed using a second 26-mm Myval valve (Figure 3E). Post–ViV aortography and TEE demonstrated no paravalvular leak or residual aortic regurgitation and a proper leaflet coaptation (Figures 3F and 4F). Hemostasis of the main femoral access site was achieved using one Perclose device and one Angio-Seal, while the secondary left radial access was managed with a pressure bandage. At the end of the procedure, a complete left bundle branch block occurred and persisted, but without significant pauses or the need for pacemaker implantation. Three days after the procedure, transthoracic echocardiography demonstrated a mean transvalvular gradient of 5 mm Hg, with no evidence of paravalvular leak. The patient was discharged on the ninth postoperative day.

Figure 3.

Operative Findings During the Transcatheter Aortic Valve Implantation With Myval Bioprosthesis

(A) Predilation using a 23 × 40-mm balloon (B) Myval bioprosthetic aortic valve with a diameter of 26 mm was deployed. (C) Aortography demonstrated severe aortic regurgitation. (D) Attempt to restore leaflet mobility through postdilation with a 25-mm balloon. (E) Valve-in-valve procedure with a second 26-mm-diameter Myval valve was performed. (F) Final aortography showed no evidence of transvalvular regurgitation.

Figure 4.

Transesophageal Echocardiography Findings During Transcatheter Aortic Valve Implantation

(A, B, D, and E) TEE demonstrated stuck leaflet and severe intraprosthetic regurgitation. (C) Graphic illustration depicting the mechanism of the frozen leaflet. (F) Transesophageal echocardiography showing restored mobility and proper leaflet coaptation after ViV implantation. TEE = transesophageal echocardiography; ViV = valve-in-valve.

Discussion

The present case reports the occurrence of frozen leaflet during balloon-expandable aortic valve implantation, representing the first case involving the Myval Octapro device documented in the literature. The occurrence of frozen leaflets has been more frequently associated with balloon-expandable valves.3, 4, 5^,9 Over the years, multiple mechanisms have been hypothesized as potential contributors to this phenomenon:¹²

• 1.Loss of alignment between the prosthetic valve and the delivery balloon, resulting in incomplete expansion of the valve's upper portion;
• 2.Severe calcifications of the native cusps, leading to entrapment of the prosthetic leaflet;
• 3.Iatrogenic damage to the leaflet during device preparation;^3,6
• 4.Intrinsic valve dysfunction related to manufacturing defects;
• 5.Hemodynamic factors, such as periprocedural hypotension;
• 6.Valve postdilation performed on an incompletely expanded or deformed prosthesis, which may result in leaflet crushing.^7,9

A careful preprocedural planning strategy could help mitigate this risk, particularly through the identification of severe calcification, which may predispose to this complication, and the adoption of appropriate predilation before valve implantation. From a diagnostic perspective, TEE plays a key role in identifying the precise location of regurgitation while minimizing radiation exposure. Although angiography provides an immediate assessment, it increases radiation dose and fails to reliably distinguish between intravalvular and paravalvular regurgitation.

Several therapeutic approaches have been described. Most cases reported in the literature involved significant hemodynamic compromise, necessitating ViV implantation. An exception was the recent report of a Portico valve case in 2024,¹⁰ in which leaflet mobility was restored with two balloon postdilation maneuvers, thus avoiding ViV implantation. Similarly, a second case of frozen leaflet occurring during ViV implantation with a self-expandable Evolut R prosthesis was successfully managed by mobilization using a pigtail catheter.¹¹ A practical management algorithm to cope with this complication during TAVI has been proposed previously,¹² and a complete diagram is shown in the Visual summary. If hemodynamics are stable, operators may attempt repositioning of the stiff guidewire, increasing systolic blood pressure, or gently manipulating the leaflet with a pigtail catheter. Balloon postdilation may also be considered. If hemodynamics are unstable, immediate circulatory support should be established, followed by urgent ViV implantation.⁶

In the case described, the implantation was performed without issues, and an appropriate pre-dilatation had been carried out. Therefore, causes related to the implantation technique are not assumed. The most likely hypothesis is instead related to a manufacturing defect or an incorrect preparation of the valve. One of the most critical phases in TAVI is the crimping process (for balloon-expandable valves), since the leaflets might be damaged during this phase. For this reason, applying an excessive crimping force is strongly discouraged.¹²

The principal limitation in providing explanations to this phenomenon is the rarity of the condition. The small number of cases described so far prevents any reliable estimation of its true incidence. For this reason, summarizing published reports in a dedicated table may help highlight shared pathophysiological and mechanical mechanisms and provide interventional cardiologists with practical guidance when facing this uncommon but potentially critical complication (Table 1).

Table 1.

Cases of Frozen Leaflet During TAVI Reported in the Literature

First Author, Year	Prosthetic Valve	Predilation Performed	No. of Frozen Leaflets	Solution	Hemodynamic Status
Al-Attar et al, 20113	23-mm balloon expandable Edwards SAPIEN valve	No	1	ViV with another 23-mm valve	Failure to improve hemodynamic status despite ECMO. The patient died a few hours after the procedure.
Agostoni et al, 20124	23-mm balloon expandable Edwards Sapien XT valve	No	1	ViV with another 23-mm valve	Severe hypotension and acute LV dysfunction not responsive to vasoactive drugs requiring resuscitation. Complete recovery after ViV.
Ben-Dor et al, 20136	23-mm balloon expandable Edwards SAPIEN valve	Yes	1	ViV with a third 23-mm valve after a second valve was implanted in the abdominal aorta due to dislodgement from the balloon	Severe hypotension occurring just after first valve implantation
Couture et al, 20165	23-mm balloon expandable SAPIEN-3 valve	Yes	1	ViV with another 23-mm valve	Rapidly worsening hypotension necessitating CPR. Rapid improvement after ViV.
Okuyama et al, 20189	23-mm SAPIEN-3 valve	Yes	3	ViV with another 23-mm valve	Cardiogenic shock occurring after postdilation of the first not-fully expanded valve. Immediate CPR and ECMO provided. Rapid improvement after ViV.
Olasinska-Wisniewska et al, 201911	23-mm Core Valve Evolut R	No	1	6F-pigtail probing of the implanted prosthesis	Hypotension followed by recurrent VF necessitating CPR. Immediate hemodynamic improvement after leaflet mobility restoration.
Totaro et al, 202410	25-mm self-expandable Portico valve	Yes	1	Two postdilations with VACSSIII 20/40 balloon	Stable. No supports or drugs needed.
Kanzaki et al, 20258	20-mm Edwards SAPIEN-3 Ultra RESILIA (S3UR)	Yes	3	ViV with another 20-mm S3UR	Severe hypotension not responding to positive inotropes/vasoconstrictors. Immediate ECMO provided. Rapid hemodynamic improvement after ViV
Yamazoe et al, 20257	23-mm Edwards S3UR	No	1	ViV with another 23-mm S3UR	Hypotension rapidly increasing after ViV

CPR = cardiopulmonary resuscitation; ECMO = extracorporeal membrane oxygenation; LV = left ventricular; TAVI = transcatheter aortic valve implantation; VF = ventricular fibrillation; ViV = valve-in-valve.

Conclusions

Frozen or stuck leaflet during TAVI is a rare but potentially life-threatening event. Early recognition and rapid hemodynamic assessment are critical to restoring leaflet mobility and maintaining procedural safety. Incorporating TEE can facilitate intraprocedural detection by accurately identifying the mechanism and location of dysfunction while minimizing radiation exposure. Adoption of a structured intervention algorithm and timely multidisciplinary involvement is essential to optimize outcomes in this high-risk situation.

Visual Summary.

Practical Algorithm for Promptly Identifying Frozen Leaflet After TAVI and Maneuvers to Restore Mobility Based on the Patient's Hemodynamic Status

BP = blood pressure; TAVI = transcatheter aortic valve implantation; TEE = transesophageal echocardiography; ViV = valve-in-valve.

Funding Support and Authors Disclosure

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.