CASE REPORT – ADULT CARDIAC

Interactive CardioVascular and Thoracic Surgery 21 (2015) 389–390 doi:10.1093/icvts/ivv150 Advance Access publication 11 June 2015

Cite this article as: Stamm C, Pasic M, Buz S, Hetzer R. Vent-induced prosthetic leaflet thrombosis treated by open-heart valve-in-valve implantation. Interact CardioVasc Thorac Surg 2015;21:389–90.

Vent-induced prosthetic leaflet thrombosis treated by open-heart valve-in-valve implantation Christof Stamm*, Miralem Pasic, Semih Buz and Roland Hetzer Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Berlin, Germany * Corresponding author. Deutsches Herzzentrum Berlin, Cardiothoracic and Vascular Surgery, Augustenburger Platz 1, 13353 Berlin, Germany. Tel: +49-30-45932109; fax: +49-30-45932100; e-mail: [email protected] (C. Stamm). Received 6 November 2014; received in revised form 3 May 2015; accepted 5 May 2015

Abstract A patient required emergency mitral valve replacement and extracorporeal membrane oxygenation (ECMO) support for acute biventricular failure. The left ventricular (LV) vent inserted via the left upper pulmonary vein induced thrombotic immobilization of a prosthetic valve leaflet, with significant intra-prosthesis regurgitation after ECMO explantation. Therefore, the left atrium was opened on the beating heart during conventional extracorporeal circulation, all prosthesis leaflets were excised and a 29-mm expandable Edwards Sapien prosthesis was inserted within the scaffold of the original prosthesis under direct vision. This case illustrates the benefits and potential problems of LV venting on ECMO support, and a rapid and safe way of replacing the prosthesis leaflets in a critical situation.

CASE A 77-year old man with coronary artery disease, aortic valve stenosis and mild mitral regurgitation underwent aortic valve replacement with a bioprosthesis and aortocoronary bypass grafting. Three hours postoperatively, the patient developed increasing inotrope demand, lactacidosis and elevated left atrial pressure. Echocardiography displayed severe mitral regurgitation with a central coaptation deficit mainly caused by annular dilatation and distortion of the anterior leaflet by mattress sutures in the aortomitral continuity. Left ventricular (LV) contractile function was mildly reduced [left ventricular ejection fraction (LVEF) = 45, Fig. 1A], and elevated creatine kinase levels in the presence of patent bypass grafts suggested intraoperative myocardial protection deficit. The decision was made to return the patient to the operating theatre and to replace the mitral valve, and a 31-mm Medtronic Hancock II bioprosthesis was implanted. Now, weaning from extracorporeal circulation was not possible because biventricular function was severely impaired, and a central right atrialto-aortic extracorporeal membrane oxygenation (ECMO) system was implanted. Despite adequate ECMO flow (>3.5 l/m2/min), the LV appeared ballooned, and a 20-Fr vent catheter was inserted via the left upper pulmonary vein into the LV cavity. The vent line was connected with the main venous line via a Y-shaped adapter with no extra pump, and negative pressure of 80–100 mmHg provided adequate LV decompression. Intravenous (i.v.) heparin was started once bleeding had ceased, and a partial thromboplastin time (PTT) >50 s was first recorded 24 h after ECMO initiation. After 5 days on ECMO support, LV function had recovered and the ECMO system was explanted. However, transoesophageal echocardiography

(TEE) now showed significant regurgitation within the mitral valve prosthesis (MVP), because the posterior-most leaflet was immobile in the open position with evidence of thrombus deposition seen by echocardiography, most likely caused by the previous transvalvular vent catheter despite adequate anticoagulation (Fig. 1B and C). The decision was made to apply a beating heart approach for revision of MVP in order to avoid another period of aortic crossclamping. The patient was fully heparinized and placed on conventional extracorporeal circulation (ECC), the left ventricle decompressed with a transatrial vent. The left atrium was opened, making sure that no air was ejected by keeping the mean arterial pressure >80 mmHg under continuous echocardiographic monitoring. The leaflet was immobilized by thrombotic material, and all three prosthetic leaflets were excised with the prosthesis scaffold being left in place, and a 29-mm Edwards Sapien valve was inserted and expanded within the prosthetic annulus (Fig. 1D). Then, the atriotomy was closed, the heart de-aired and MVP competence was ascertained by contrast echocardiography. ECC could be terminated with mild inotrope support and adequate LV function (LVEF = 52% by TEE). Haemodynamics and peripheral organ function continued to recover, and the patient was extubated, mobilized and referred to cardiac rehabilitation.

COMMENT This case illustrates the pitfalls of LV decompression and ECMO support in the presence of an artificial mitral valve, and offers a novel solution for quick and safe replacement of the prosthesis. We always aim at achieving complete LV unloading in all patients with

© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

CASE REPORT

Keywords: Mitral valve • Extracorporeal membrane oxygenation • Valve-in-valve procedure

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C. Stamm et al. / Interactive CardioVascular and Thoracic Surgery

Figure 1: Transoesophageal echocardiograms indicating (A) severe mitral valve regurgitation X hours after aortic valve replacement and coronary artery bypass grafting surgery; (B) intraprosthesis regurgitation due to LV vent catheter-induced thrombosis of one leaflet (arrow); (C) 3D reconstruction showing thrombus formation on the immobile leaflet (arrow); (D) competent mitral valve prosthesis after on-pump, beating heart leaflet excision and implantation of a 29-mm Edwards Sapien valve. LV: left ventricular.

post-cardiotomy LV failure and consider it crucial for myocardial recovery. In this case, however, the vent catheter immobilized one leaflet for 5 days, leading to local thrombus formation and leaflet adhesion. To prevent this problem, a trans-myocardial LV vent could be inserted via the LV apex, but we repeatedly saw bleeding complications in patients who developed coagulation disorders. LV unloading using a transaortic Impella® device has also been described [1], but, in our experience, leads to exacerbated haemolysis when combined with ECMO. Clearly, stringent anticoagulation is also mandatory so as to avoid thrombotic complications under ECMO support when blood flow stagnates in the LV, but it needs to be balanced against bleeding complications. We start i.v. heparin (PTT 55–60 s) as soon as bleeding has ceased and give platelet inhibitors only if coronary stents are present. If a valve-related complication occurs, the fragile haemodynamic balance early after ECMO weaning may break down when another period of aortic crossclamping is employed in order to replace the valve. Catheter-based insertion of expandable valves into aortic valve prostheses has become a routine procedure, and valve-in-valve placement in degenerated mitral bioprosthesis has also been reported before [2]. Here, however, we feared that fresh thrombotic material may embolize if a catheter-based valve-in-valve procedure was done off-pump in the ejecting heart. We therefore decided to open the

left atrium on ECC with the heart beating empty. By venting the LV prior to opening the atrium and excising the leaflets, ejection of air into the aorta is prevented and sufficient exposure is provided for rapid and safe placement of an expandable valve-in-valve prosthesis under direct vision. No extra equipment is needed other than the standard MVP delivery device, and appropriate valve anchorage can be ensured immediately. This technique may help improve the outcome of patients in the desperate setting of combined ECMO-related intracardiac thrombosis and prosthetic valve dysfunction [3]. Conflict of interest: none declared.

REFERENCES [1] Cheng A, Swartz MF, Massey HT. Impella to unload the left ventricle during peripheral extracorporeal membrane oxygenation. ASAIO J 2013;59:533–6. [2] Wilbring M, Alexiou K, Tugtekin SM, Sill B, Hammer P, Schmidt T et al. Transapical transcatheter valve-in-valve implantation for deteriorated mitral valve bioprostheses. Ann Thorac Surg 2013;95:111–7. [3] Gottfried R, Paluszkiewicz L, Kizner L, Morshuis M, Koertke H, Gummert J. Thrombosis of a bioprosthetic mitral valve under extracorporeal membrane oxygenation: thrombus formation in the left heart. Ann Thorac Surg 2012; 94:657.

Vent-induced prosthetic leaflet thrombosis treated by open-heart valve-in-valve implantation.

A patient required emergency mitral valve replacement and extracorporeal membrane oxygenation (ECMO) support for acute biventricular failure. The left...
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