Ann Thorac Surg 2009;88:992-994. doi:10.1016/j.athoracsur.2009.01.052
© 2009 The Society of Thoracic Surgeons
Case Reports
Awake Transapical Aortic Valve Implantation Using Thoracic Epidural Anesthesia
Chirojit Mukherjee, MDa,*,
Thomas Walther, MD, PhDb,
Michael Andrew Borger, MD, PhDb,
Joerg Kempfert, MDb,
Gerhard Schuler, MD, PhDc,
Friedrich Wilhelm Mohr, MD, PhDb,
Joerg Ender, MDa
a Department of Anesthesiology, Heart Center Leipzig, University Leipzig, Leipzig, Germany
b Department of Cardiac Surgery, Heart Center Leipzig, University Leipzig, Leipzig, Germany
c Department of Cardiology, Heart Center Leipzig, University Leipzig, Leipzig, Germany
Accepted for publication January 16, 2009.
* Address correspondence to Dr Mukherjee, Department of Anesthesia and Intensive Medicine II, Heart Center Leipzig, University of Leipzig, Struempellstrasse 39, Leipzig, 04289, Germany (Email: chirojit.mukherjee{at}med.uni-leipzig.de).
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Abstract
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Transapical aortic valve implantation is a minimally invasive, beating-heart procedure that normally requires a general anesthetic. We herein report an 85-year-old patient with impaired pulmonary function who underwent successful transapical aortic valve implantation while awake, using a thoracic epidural anesthetic.
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Introduction
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Transapical aortic valve implantation (TA-AVI) is a new technique of off-pump, beating heart procedure for high-risk patients with symptomatic aortic stenosis [1]. Despite its reduced invasiveness, TA-AVI is limited by the fact that patients must undergo general anesthesia with its expected risks, particularly in patients with restricted pulmonary function. Although we routinely use fast-track anesthesia in TA-AVI patients [2], avoidance of intubation and ventilation may be further beneficial. Herein we report a patient who underwent TA-AVI while awake, using a thoracic epidural anesthetic.
An 85-year-old patient was admitted with severely symptomatic aortic stenosis (AS) in New York Heart Association functional class III. Echocardiography revealed a maximum gradient of 72 mm Hg, a mean gradient of 56 mm Hg, and an aortic orifice area of 0.5 cm2. His comorbidities included left ventricular dysfunction (ejection fraction, 40%), pulmonary hypertension, and severe atherosclerotic plaques in the aorta leading to a logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) predicted risk for mortality of 35%. Of particular note, the patient refused any blood transfusion because of religious reasons. The aortic annulus was confirmed to be 24 mm in diameter by preoperative transesophageal echocardiography. His lung function tests showed an obstructive pattern with a forced expiratory volume of 1 second < 60% of predicted value. Due to his increased risk profile, the patient was scheduled for TA-AVI instead of conventional aortic valve replacement. Informed consent was obtained. In addition, the patient consented to undergo TA-AVI under a regional anesthetic with plans to convert to a general anesthetic if required.
Aspirin and low molecular weight heparin was discontinued for the patient at noon the day before surgery. Potassium clorazepat (25 mg) was administered and midazolam (7.5 mg orally) was given orally to the patient the evening before surgery as premedication. The epidural catheter was placed with the patient in the sitting position and under aseptic conditions. The T2 to T3 intervertebral space was located by method of palpation. Local anesthetic (scandicain 1%, 1 mL) was injected into the patient to facilitate introduction of the epidural needle. With an 18-guage epidural needle, the T2 to T3 space was punctured in the midline. The needle was positioned at 90° to the skin, similar to performing a lumbar epidural procedure; then epidural placement was confirmed by the "loss of resistance" technique using air and 10 mL of sterile sodium chloride. The epidural space was accessed at a depth of 6 cm from the skin and was reconfirmed with the "hanging drop" method. Ropivacaine hydrochloride (0.2%, 5 mL) was then administered as a test dose through the epidural catheter. The epidural catheter was fixed by tunneling it through the skin at the 12-cm mark, and the patient was put in a supine position. An additional bolus dose of 25 mL of 0.2% ropivacaine hydrochloride was given together with Fentanyl (200 µg) after 10 minutes. The feeling of differentiation between "warm" and "cold" was performed to assess the correct functioning of the regional blockade. A motor blockade up to the T10 level and a sensory blockade up to the T12 level were observed. Although the patient complained of tingling and numbness in both hands, there was no loss of power in either hand. Epidural infusion was started at 10 mL/h of a mixed solution of ropivacaine hydrochloride (0.2%) and fentanyl (2 µg/mL).
After sterile draping, the surgeon established the required femoral venous and arterial lines for potential rapid conversion to cardiopulmonary bypass, with use of local anesthetics. Heparin (5,000 IU) was administered intravenously to increase the baseline activated clotting time to greater than 200 sec. Elective noninvasive ventilation was started using a continuous positive airway pressure mask with a pressure set at 10 mbar. Blood gas analysis was performed every 15 minutes.
After confirmation of adequate motor blockade, a standard anterolateral mini-thoracotomy was performed in the sixth intercostal space to reach the apex of the left ventricle. An epicardial pacing wire was placed and connected for rapid ventricular pacing during balloon valvuloplasty and valve implantation. Valve implantation was performed under fluoroscopic guidance in a standard fashion as previously described [1, 3]. After implantation, valve function was reconfirmed using angiography. The left ventricular apex was closed, one chest tube was inserted, and the chest was closed in a routine fashion. After insertion of the chest drain, the continuous positive airway pressure mask was disconnected and converted to a full-face plastic mask. The entire procedure lasted 55 minutes, and communication was maintained with the patient throughout.
The patient was transferred directly to the post-anesthetic care unit and 1 hour later to the step down unit, without any stay in the intensive care unit. Postoperative pain therapy was delivered through the epidural catheter at 6 mL/hr using ropivacaine hydrochloride (0.2%), and the therapy was discontinued on postoperative day 4 when the patient was transferred to the regular ward. He was discharged on postoperative day 13 and is alive and doing well at his 30-day follow-up (Figs 1 and 2).
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Comment
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Transcatheter aortic valve implantation is a new and emerging technique that has been performed in elderly and higher risk patients suffering severe symptomatic aortic stenosis [3]. It has been estimated that a relatively large number of elderly patients with symptomatic AS are not being referred to surgery because of high operative and anesthetic risks. Providing lower risk strategies that are both surgical and anesthesiological may make further treatment options available for such higher risk patients [3].
Thoracic epidural anesthesia for cardiac surgery has its roots in the groundbreaking work by Blomberg and colleagues [4, 5] and Kessler and colleagues [6] who were the first to describe a beating heart coronary artery bypass graft operation in awake patients using thoracic epidural anesthesia, but patients were intubated whenever the pleural space was opened because of the accompanying pneumothorax. During TA-AVI, however, opening of the intrapleural space is essential to access the apex of the heart. Therefore, we applied continuous positive airway pressure to the lung with the use of noninvasive ventilation to avoid a pneumothorax and collapse of the affected lung.
The current patient did not complain of pain during or early after the operation, with visual analogue pain scores remaining consistently between 0 and 1 (on a scale of 0 to 10). There was no evidence of ropivacaine overdose, such as nausea, vomiting, or a metallic taste in the mouth, and no evidence of neurologic complications. On postoperative day 3, aspirin and low molecular weight heparin were discontinued, and the epidural catheter was removed on the following day.
Although the current patient had an uneventful course, high thoracic epidural anesthesia in heparinized patients should be performed with caution. There is a remote but distinct possibility of epidural hematoma formation and subsequent paralysis. Although this complication is more unlikely in TA-AVI than conventional cardiac surgery patients, because of the low heparin dose that is administered (5,000 units), great care should be taken to avoid a bloody tap whenever possible. If a bloody epidural tap is encountered, the operative procedure should be delayed at least 24 hours.
Our case study demonstrates that TA-AVI is feasible in an awake patient under thoracic epidural anesthesia, and may be particularly beneficial in patients with underlying pulmonary disease. The satisfactory results and low pain scores reported by the patient were encouraging. We have performed seven such procedures to date, with 2 patients who required conversion to general anesthesia. One patient had a panic attack and required sedation, whereas the second patient required a sternotomy and cardiopulmonary bypass due to a surgical complication. The remaining 5 patients had an uneventful and satisfactory outcome. Further evaluation in a larger number of patients will be required to establish the safety and efficacy of this procedure during TA-AVI.
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References
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- 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]
- Ender J, Borger MA, Funkat AK, et al. Cardiac surgery fast track treatment in a postanesthetic care unit: six month results of the Leipzig fast track concept Anesthesiology 2008;109:61-66.[Medline]
- Walther T, Chu MWA, Mohr FW. Transcatheter aortic valve implantation: time to expand? Curr Opin Cardiol 2008;23:111-116.[Medline]
- Blomberg S, Emanuelsson H, Kvist H, et al. Effects of thoracic epidural anesthesia on coronary arteries and arterioles in patients with coronary artery disease Anesthesiology 1990;73:840-847.[Medline]
- Kock M, Blomberg S, Emanuelsson H, Lomsky M, Stromblad SO, Ricksten SE. Thoracic epidural anesthesia improves global and regional left ventricular function during stress-induced myocardial ischemia in patients with coronary artery disease Anesth Analg 1990;71:625-630.[Abstract/Free Full Text]
- Kessler P, Aybek T, Neidhart G, et al. Comparison of three anesthesia techniques for off-pump coronary artery by-pass grafting: general anesthesia, combined general and high thoracic epidural anesthesia or high thoracic epidural alone JCTVA 2005;19:32-39.
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Abstract
Introduction
