Ann Thorac Surg 2008;86:1665-1668. doi:10.1016/j.athoracsur.2008.04.057
© 2008 The Society of Thoracic Surgeons
Case Reports
Minimally Invasive Off-Pump Aortic Valve Implantation: The Surgical Safety Net
Joerg Kempfert, MDa,
Thomas Walther, MD, PhDa,*,
Michael A. Borger, MD, PhDa,
Sven Lehmann, MDa,
Johannes Blumensteina,
Jens Fassl, MDb,
Gerhard Schuler, MD, PhDc,
Friedrich-Wilhelm Mohr, MD, PhDa
a Department of Cardiac Surgery, Heartcenter, University of Leipzig, Leipzig, Germany
b Department of Anesthesiology, Heartcenter, University of Leipzig, Leipzig, Germany
c Department of Cardiology, Heartcenter, University of Leipzig, Leipzig, Germany
Accepted for publication April 16, 2008.
* Address correspondence to Dr Walther, Herzzentrum Leipzig, Struempellstrasse 39, Leipzig, 04289, Germany (Email: walt{at}medizin.uni-leipzig.de).
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Abstract
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Minimally invasive techniques for transcatheter aortic valve implantation are rapidly developing. Feasibility of off-pump, sternal-sparing aortic valve implantation has already been demonstrated, initial clinical results are promising, and there will be further technical improvements. However, any complication, some even unknown thus far, can occur at any time during transcatheter aortic valve implantation requiring conversion to cardiopulmonary bypass and conventional surgery. We present a case of left mainstem occlusion during minimally invasive off-pump transapical aortic valve implantation focusing on bail-out strategies. Due to the "surgical safety-net," cardiopulmonary bypass was immediately established, and after coronary bypass grafting, the patient recovered and was discharged from the hospital.
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Introduction
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Minimally invasive techniques for transcatheter aortic valve implantation have been developed and introduced for clinical use during the past years. At present, elderly patients with significant comorbidities having an increased perioperative risk profile are considered potential candidates for off-pump beating heart, aortic valve implantation. Recently, two catheter-delivered valve systems have entered first clinical trials. Feasibility has been proven for the self-expanding, Nitinol-based CoreValve [1] (CoreValve, Paris, France) and for the balloon-expandable, Edwards Sapien prosthesis [2] (Edwards Lifesciences Inc, Irvine, CA). Both prostheses under current clinical use can be implanted using the retrograde transfemoral or the antegrade transapical approach.
Transcatheter aortic valve implantation is the first truly minimal invasive approach enabling off-pump aortic valve implantation and avoiding partial or complete sternotomy. Initial clinical results are promising [2], but we have to keep in mind that this exciting evolving technology is still in its early clinical phase and major complications can occur at any step during the procedure, requiring immediate conversion to an on-pump technique in case of hemodynamic instability.
An 82-year-old woman with a high surgical risk (logistic EuroSCORE risk for mortality, 56.7%; The Society of Thoracic Surgeons' risk score, 23.8%) and symptomatic aortic stenosis was admitted for off-pump minimally invasive transapical aortic valve implantation. Comorbidities included severe calcifications of the aorta and the peripheral vessels. Prior to surgery, the patient had two episodes of ventricular fibrillation in the hospital that required cardiopulmonary resuscitation. A magnetic resonance imaging scan revealed only minor cerebral lesions and transapical aortic valve implantation was indicated as the ultimo ratio. The operation was performed under general anesthesia. Monitoring included left radial arterial blood pressure, right internal jugular central venous pressure, and transesophageal echocardiography.
According to our standard protocol, a venous guidewire was inserted percutaneously into the right femoral vein and advanced under transesophageal echocardiography-guidance until reaching the right atrium. In addition, an arterial sheath was placed into the right femoral artery, which is needed anyhow to insert a pigtail catheter for aortic root angiography. A primed heart-lung machine and extra long tubes (not connected) are additionally available. This allows for immediate insertion of arterial and venous cannulas and then conversion to cardiopulmonary bypass to stabilize hemodynamic function in any patient if required (Fig 1). This set-up guarantees a "surgical safety-net" to perform any surgical bailout procedures (conventional aortic valve replacement, coronary artery bypass grafting, and so forth) if required.
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Fig 1. "Surgical safety-net" of percutaneously inserted venous wire and arterial sheath in the right femoral vessels.
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Transapical aortic valve implantation was performed off-pump as previously described through a small, anterolateral mini-thoracotomy in this patient [2]. After balloon valvuloplasty, which was performed during the first episode of rapid ventricular pacing to unload the left ventricle, the delivery system was bluntly inserted, and the valve prosthesis was advanced under fluoroscopic guidance. The left angiogram of Figure 2
visualizes the aortic root and the coronary arteries. Severe aortic calcification is clearly visible. At this stage, prior to final positioning, the crimped prosthesis is still above the aortic annulus. In the next step, the valve was advanced into the final position and deployed by balloon inflation under a second episode of rapid pacing. The right image of Figure 2 shows this process with the valve in a good position. Despite an uneventful implantation just at the target area bisecting the aortic annulus with the steel stent, we observed hemodynamic compromise. Angiographic control (Fig 3) revealed complete occlusion of the left main stem, which required immediate conversion. With the valve in a stable position, cardiopulmonary resuscitation was initiated. Using the "safety-net," cardiopulmonary bypass could be established within 2 minutes, bridged by external chest compression. The patient received two coronary artery bypass grafts on the beating heart, on-pump (left internal thoracic artery to left anterior descending and saphenous vein to first marginal), and an intra-aortic balloon pump was implanted. Weaning from cardiopulmonary bypass was successful with moderate inotropic support. The patient was extubated and the intra-aortic balloon pump was withdrawn on postoperative day 1. Further recovery was uneventful without any neurologic deficit, and the patient was well with persistently good aortic valve function at the 4-month follow-up.
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Fig 2. Left: angiographic visualization of the aortic root and the coronary arteries with the crimped prosthesis above the annulus before final positioning (white line indicating the ventricular edge of the aortic annulus). Right: deployment after exact positioning of the prosthesis (white line indicating the ventricular edge of the aortic annulus).
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Fig 3. Final result after valve implantation with arrow indicating the location of the occluded left main stem.
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Comment
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Aortic valve replacement is the golden standard and curative therapy for patients with symptomatic aortic stenosis. As such, aortic valve stenosis is usually caused by degenerative changes in the western communities, occurring most frequently in the elderly. Elderly patients on the other hand may suffer multiple comorbidities leading to a significant increase in surgical risk [3]. According to a survey of the European Society of Cardiology in 2003 [4], one third of these patients are only referred to surgery [5]. In contrast, it has been demonstrated that quality of life, the most important outcome variable in this patient group, is improved after valve replacement [6]. Judging this and the poor survival of patients receiving no surgical treatment, aortic valve replacement [7] is almost always justified, even in the presence of a significantly increased perioperative risk [8].
The recently developed technique of transcatheter aortic valve implantation is the first truly minimally invasive approach to treat aortic valve disease, avoiding sternotomy and cardiopulmonary bypass. Despite all successful implantations so far, we have to keep in mind that major complications may occur at any time during such procedures. In the case presented here, occlusion of the left main stem occurred, despite an uneventful implantation process without significant antegrade movement. The final position before deployment seemed correct, with the annulus bisecting the prosthesis, which is 15 mm high. Figure 4
(top) reveals a distance of only 11 mm of the left main stem from the aortic annulus (usually 13 to 17 mm); theoretically this should still result in a safety margin of 3.5 mm, but the postoperative computed tomographic scan confirmed the occlusion of the left main stem by the prosthesis itself. In case of a short distance between the coronary arteries and the aortic annulus, the indication for transapical aortic valve implantation using a balloon-inflatable prosthesis should be carefully considered. Fortunately, severe complications are rare. However, the potential risks of obstructing coronary arteries, or of distal or proximal dislocation of the prosthesis, or of aortic root dissection and rupture, among others, have to be kept in mind. When using a full-team approach with a cardiac surgeon involved during transcatheter aortic valve implantation and the procedure being performed in a fully equipped hybrid surgical theater, all options for conversion are safely available. This leads to an utmost safety for the patient. The "safety-net" described in this case should become a standard approach to allow for fast cannulation and connection to cardiopulmonary bypass, and thus provide optimal outcome for the patients, even in case of conversion. Transcatheter aortic valve implantation should be performed by a team of specialists including cardiac surgeons, cardiologists, and anesthetists, using a hybrid operating room, if possible. The team approach will lead to an optimal outcome for high-risk patients.
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Fig 4. Top: preoperative computed tomographic scan delineating the distance between the left main stem (arrow) and the aortic annulus (dashed line). Bottom: postoperative computed tomographic scan demonstrating left main (arrow) occlusion by the implanted prosthesis.
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References
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- Grube E, Schuler G, Buellesfeld L, et al. Percutaneous aortic valve replacement for severe aortic stenosis in high-risk patients using the second- and current third-generation self-expanding core valve prosthesis: device success and 30-day clinical outcome J Am Coll Cardiol 2007;50:69-76.[Abstract/Free Full Text]
- Walther T, Falk V, Borger MA, et al. Minimally invasive transapical beating heart aortic valve implantation—proof of concept Eur J Cardiothorac Surg 2007;31:9-15.[Abstract/Free Full Text]
- Sundt TM, Bailey MS, Moon MR, et al. Quality of life after aortic valve replacement at the age of > 80 years Circulation 2000;102(90003):III-70-III-74.[Medline]
- Iung B, Baron G, Butchart EG, et al. A prospective survey of patients with valvular heart disease in Europe: The Euro Heart Survey on Valvular Heart Disease Eur Heart J 2003;24:1231-1243.[Abstract/Free Full Text]
- Iung B, Cachier A, Baron G, et al. Decision-making in elderly patients with severe aortic stenosis: why are so many denied surgery? Eur Heart J 2005;26:2714-2720.[Abstract/Free Full Text]
- Huber CH, Goeber V, Berdat P, et al. Benefits of cardiac surgery in octogenarians—a postoperative quality of life assessment Eur J Cardiothorac Surg 2007;31:1099-1105.[Abstract/Free Full Text]
- Varadarajan P, Kapoor N, Bansal RC, et al. Survival in elderly patients with severe aortic stenosis is dramatically improved by aortic valve replacement: results from a cohort of 277 patients aged
80 years Eur J Cardiothorac Surg 2006;30:722-727.[Abstract/Free Full Text] - Melby SJ, Zierer A, Kaiser SP, et al. Aortic valve replacement in octogenarians: risk factors for early and late mortality Ann Thorac Surg 2007;83:1651-1657.[Abstract/Free Full Text]
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Abstract
Introduction
