Transcatheter Vacuum-Assisted Mass Extraction on a Mitral Bioprosthesis

Abstract

An 84-year-old woman with a history of mitral valve replacement, ascending aorta replacement, and pacemaker implantation presented with malaise and progressive shortness of breath. Transthoracic echocardiography and transesophageal echocardiography revealed a left ventricular ejection fraction of 10% to 15% and a floating mass on the mitral prosthesis. She was suspected to have bioprosthetic endocarditis, despite being afebrile and having negative blood cultures. Reoperative mitral valve replacement was considered but deemed too high risk, and a transseptal aspiration of a mass was performed to mitigate systemic embolization risk. Postprocedural transesophageal echocardiography showed no residual mass and a well-functioning bioprosthesis. The pathologic examination revealed extensive fibrin accompanied by inflammation and a fibroblastic reaction. Vacuum-assisted aspiration using the AngioVac has been well described for right-sided intracardiac structure, but left-sided mass extraction has rarely been reported. This successful case illustrates a transcatheter treatment option in an otherwise inoperable patient.

Visual Summary

The presence of a floating mass attached to the mitral valve is an urgent indication for surgical intervention because of the high embolic risk. Although surgical intervention remains the standard approach for managing mass removal—especially in patients with valve dysfunction, persistent bacteremia due to infective mitral valve endocarditis, or extensive tissue destruction—not all patients are candidates for surgery.

Take-Home Message

• •Percutaneous transseptal extraction of a mass on the mitral valve was successfully performed in a patient with prohibitive surgical risk.

In patients with prohibitive surgical risks, percutaneous methods have emerged as alternatives for mass removal on the mitral valve. The AngioVac system (AngioDynamics), originally designed for right-sided heart mass extraction, has shown potential benefit in off-label use for left-sided intracardiac masses.1, 2, 3, 4

This case report details the successful use of the transseptal aspiration of a mass on a mitral prosthesis in an 84-year-old woman with a history of mitral valve replacement and ascending aorta replacement.

Case Summary

An 84-year-old woman underwent mitral valve replacement with a 27-mm Mosaic valve (Medtronic) and ascending aorta replacement 6 years ago. She had undergone pacemaker implantation for postoperative complete heart block. She presented with malaise and progressive shortness of breath. Transthoracic echocardiography followed by transesophageal echocardiography (TEE) revealed a reduced left ventricular ejection fraction of 10% to 15% and a floating mass on the mitral prosthesis (Figure 1). There was trace mitral regurgitation with no perivalvular leakage. She was suspected to have bioprosthetic endocarditis, although she had been afebrile with negative blood cultures. Reoperative mitral valve replacement was considered but deferred because of high surgical risk. The multidisciplinary team proposed transseptal mass aspiration to mitigate the risk for systemic embolization. The AngioVac system was used through a femoral venous and transseptal approach, successfully extracting 2 pieces of the intracardiac mass (Figure 2, Figure 3, Figure 4). Postprocedural evaluation with TEE confirmed the absence of residual masses and a well-functioning mitral valve bioprosthesis (Figure 5). The pathologic examination was consistent with abundant fibrin with inflammation and fibroblastic reaction (Figure 6).

Figure 1.

Preprocedural Transthoracic Echocardiography Revealed a Substantial Mobile Mass on the Bioprosthesis

The blue arrow indicates the mobile mass on the bioprosthesis. LA = left atrium; LV = left ventricle.

Figure 2.

Intraprocedural Transesophageal Echocardiogram Showing Transseptal Puncture

LA = left atrium; RA = right atrium.

Figure 3.

Intraprocedural Transesophageal Echocardiogram Showing AngioVac System Approaching the Mass

The blue arrow indicates the AngioVac system.

Figure 4.

Removed Specimen

Figure 5.

Postprocedural Transesophageal Echocardiography Revealed no Residual Mass and a Well-Functioning Mitral Valve Bioprosthesis

Abbreviations as in Figure 1.

Figure 6.

Pathologic Findings Revealed Abundant Fibrin With Inflammation and Fibroblastic Reaction

The postprocedural course was uneventful. The patient is doing well clinically, and follow-up echocardiography revealed a well-functioning mitral bioprosthetic without visible mass.

Procedural steps

The AngioVac system includes a suction cannula, an extracorporeal membrane oxygenation (ECMO) circuit including a filter, and a reinfusion cannula.

The AngioVac cannula is intended for the removal of fresh, soft thrombi or emboli with extracorporeal bypass. Blood that is aspirated is simultaneously reinfused back into the patient’s body with the circuit to minimize blood loss. There are 2 cannulas available, with 20° and 180° angled tips. A self-expanding Nitinol funnel-shaped tip allows drainage using a slider over the sheath. The outer sheath allows funnel protrusion, curve manipulation, and capture.

The AngioVac transseptal technique for removal of the mitral valve mass involved the following steps under general anesthesia and transesophageal echocardiographic and fluoroscopic guidance:

• 1.Cerebral embolic protection: A cerebral embolic protection device, such as TriGUARD (Keystone Heart) or Sentinel (Boston Scientific), can be deployed to protect the patient from cerebral embolism. In our case, cerebral protection was not performed, because of the difficult vascular access.
• 2.Cannulation of femoral veins: A DrySeal (W. L. Gore) introducer sheath was cannulated in either femoral vein. An infusion cannula was positioned in the contralateral femoral vein to allow blood return. Heparin was administered to achieve an appropriate activated clotting time.
• 3.Transseptal puncture and atrial septostomy: Transeptal puncture followed by atrial septostomy was performed under fluoroscopic and transesophageal echocardiographic guidance. A 22-F, 180° angled-tip cannula was advanced through the DrySeal sheath in the femoral vein into the left atrium. The cannula was manipulated to bend and reach the floating mass on the mitral bioprosthesis (Figure 2).
• 4.Mass extraction: The suction circuit was established by connecting the AngioVac cannula and infusion cannula to the ECMO circuit. ECMO flow was gradually increased, and suction was applied to remove the floating mass. In this case, 2 pieces of intracardiac mass were aspirated (Figure 4).
• 5.Removal of cannula: The suction cannula and the sheath were withdrawn from the heart, reinfusion of the blood was completed, and the femoral vein cannulas were removed.

Potential Pitfalls

The transseptal AngioVac procedure, although effective in this case, presents several challenges. First, there is a risk for embolization, especially without cerebral protection. Additionally, as the AngioVac system is designed for right-sided heart structures, using it for left-sided masses such as those on the mitral valve may confer unique challenges. For example, transseptal puncture for a left-sided AngioVac procedure can cause hemodynamic changes, including right-to-left interatrial shunting or pericardial effusion that need to be ruled out by TEE. Careful patient selection and procedural planning are crucial to mitigate these risks.

For mitral valve mass removal with AngioVac system, the transapical approach has also been applied.^5,6 In the transapical approach, left thoracotomy is used, and the mitral valve is approached through the left ventricle. Some advantages to the transapical approach are that it does not require a septal puncture and that it involves a direct approach to the mitral valve. However, some disadvantages are that the transapical approach is associated with an increased risk for mitral valve subvalvular apparatus damage during left ventricular navigation and complications such as bleeding and reduced left ventricular function.

In case the mass goes to the ventricular side, it is possible to engage the mass with the AngioVac system to the ventricular side, past the mitral valve. To do so, the cannula may cross the mitral valve, and low suction would be applied to ensure that the mass is captured without catching the mitral apparatus.

Although not required in this case, in cases of significantly adherent masses, the use of assistance devices such as snares (eg, Amplatz Goose Neck [Medtronic], EN Snare [Hatch Medical], or the Micro Elite Snare [Teleflex]) can facilitate the removal of the mass. Snare devices can allow entrapment of such masses with concomitant aspiration to provide complete removal. In addition to snare devices, the use of Amplatz Stiff [Medtronic] wires or pigtail catheters can also be used, but with precautions to avoid structural complications.

A newer system for the aspiration system, the AlphaVac system (AngioDynamics), has a similar cannula, but the aspiration system is manual rather than motorized and does not have a reinfusion cannula.⁷ Compared with the AngioVac system, the AlphaVac system may be beneficial given that it does not require ECMO circulation and contralateral cannulation for reinfusion. For an institution that has difficulty establishing ECMO, AlphaVac is a solution that might be prioritized, but in this case, the AngioVac was considered more effective and appropriate for this procedure, allowing greater ease and control in suction of the mass and a smoother mass removal.

Conclusions

This case underscores the clinical importance of the AngioVac system in providing a minimally invasive alternative for high-risk patients requiring left-sided intracardiac mass removal. It offers a potential transcatheter solution for otherwise inoperable patients, highlighting its significance in reducing embolic risks associated with mitral valve prosthetic masses.

Visual Summary.

Transseptal AngioVac for Mass on a Mitral Bioprosthesis

Funding Support and Author Disclosures

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

Appendix

Video 1

Transcatheter Vacuum-Assisted Mass Extraction on a Mitral Bioprosthesis