Ann Thorac Surg 2002;73:673-674
© 2002 The Society of Thoracic Surgeons
How to do it
An alternative surgical approach to facilitate minimally invasive mitral valve surgery
Dimitrios C. Angouras, MDa,
Robert E. Michler, MD*a
a Division of Cardiothoracic Surgery, Ohio State University Medical Center, Columbus, Ohio, USA
Accepted for publication July 30, 2001.
* Address reprint requests to Dr Michler, Cardiothoracic Surgery and Transplantation, OSU Heart Hospital, The Ohio State University Medical Center, N847 Doan Hall, 10 West 10th Ave, Columbus, OH 43210, USA
e-mail: michler.l{at}osu.edu
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Abstract
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An alternative approach to minimally invasive mitral valve surgery is described that permits direct great vessel cannulation and direct aortic clamp occlusion through a 6- to 8-cm incision. This approach reduces the complexity of the procedure, and hopefully, will contribute to more widespread adoption of less invasive techniques in mitral valve surgery.
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Introduction
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After the first reports of minimally invasive mitral valve surgery in 1996 [1, 2], there has been increasing interest in simplifying the operation so that it can be widely applied to benefit patients. A variety of approaches have been reported [1–6] seeking the goal of reducing surgical trauma and postoperative morbidity, while remaining safe and effective. Invariably, these techniques have included femoral cannulation and some modification to achieve aortic occlusion, either with a special cross-clamp or an intraluminal balloon occluder. However, the further a technique is modified from that which surgeons are accustomed to employing, the greater the risk of the new technique not being widely adopted.
This report seeks to describe an alternative minimally invasive approach to the mitral valve, which permits direct aortic and bicaval cannulation, as well as direct aortic clamp occlusion. It is our belief that this approach may simplify the procedure sufficiently to permit more widespread adoption of the 6-cm to 8-cm anterior thoracotomy incision.
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Technique
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The patient is intubated with a double-lumen endotracheal tube for single-lung ventilation and positioned with the right side of the chest elevated 30 degrees with the use of a sandbag. The right arm is padded and suspended over the head or on an ether screen. Standard hemodynamic monitoring is utilized, including intraoperative transesophageal echocardiography. Transcutaneous defibrillator pads are placed on the back and over the left lateral chest wall.
A 6-cm to 8-cm transverse thoracic incision is performed over the fourth rib beginning just lateral to the left nipple. The right lung is deflated and the chest is entered through the third intercostal space. No bone or cartilaginous rib segments need to be resected or divided.
A reusable pediatric chest retractor is utilized, and under direct vision, the pericardium is incised parallel and 2 cm anterior to the phrenic nerve from the diaphragm to the aortic reflection. The edges of the pericardium are suspended to the skin and to the undersurface of the inner chest wall. This provides excellent visualization and access to the ascending aorta and superior vena cava (SVC). Heparin is administered and direct aortic and SVC cannulation is performed under direct vision in the usual manner. A caval snare is passed around the SVC and an antegrade cardioplegia catheter is placed in the aortic root.
The retractor is now removed, the fourth intercostal space entered, and the retractor repositioned into the fourth interspace. Cardiopulmonary bypass is instituted, and with decompression of the heart, one can easily cannulate the inferior vena cava (IVC) and pass a caval snare around the IVC. Through the right atrium a catheter is inserted into the coronary sinus for retrograde cardioplegia.
The interatrial groove is dissected and a stab wound is placed in the left atrium for venting of the heart. The aorta is then cross-clamped with a standard aortic clamp positioned easily through the third interspace incision. Antegrade and retrograde cardioplegia is administered and the SVC and IVC may be snared as per the surgeons’ routine. It is our practice not to snare either vena cava because it permits drainage of cardioplegia without distension of the right atrium.
The presence of a patent foramen ovale or atrial septal defect will require caval snaring. In these circumstances, it is our practice to close the atrial defect directly through the left atriotomy. Excellent exposure of the mitral valve is obtained through a left atriotomy. However, some surgeons may prefer a right atriotomy and a transseptal approach to the mitral valve.
Because the SVC and aortic cannulas pass through the third interspace, they are retracted away from the operative field, permitting unencumbered visualization and access through the fourth interspace to the mitral valve for repair or replacement. No specially designed instruments are required, and the knots may be tied by hand or with a knot pusher. Several tricks to knot tying have been learned with experience, and include delivery of the mitral valve annulus closer to the surgeon by having the anesthesiologist gently insufflate the left lung or by having the assistant hold up on the annular sutures during knot tying.
After completion of the procedure, the left ventricle is vented with a catheter positioned across the mitral valve and the atriotomy is partially closed. Carbon dioxide inflation may be instituted at this time. Careful complete evacuation of intracardiac air is performed through the left atrium and aortic root and confirmed by transesophageal echocardiography.
Temporary ventricular and atrial pacing wires are placed. Before termination of cardiopulmonary bypass, the IVC and retrograde cannulas are removed through the fourth interspace and reinforcing sutures are placed in these cannulation sites. Cardiopulmonary bypass is discontinued, and once the patient is stable, the SVC, antegrade cardioplegia, and aortic cannulas are removed through the third interspace. The right pleural space is drained with two chest tubes and the intercostal spaces are closed with three or four No. 2 Maxon pericostal sutures passed from the second to the fifth interspaces and tied snugly.
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Comment
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The proposed modification to the minithoracotomy incision for mitral valve surgery has several advantages that may permit more widespread adoption of this technique. With the aortic and SVC cannulas, antegrade cardioplegia catheter, and aortic cross-clamp all passing through the third intercostal space, the operative field is not obscured by these cannulas, and the 6-cm to 8-cm skin incision provides excellent exposure of the mitral valve through the fourth interspace. Moreover, direct cannulation of the aorta and superior and inferior vena cava is easily accomplished. Complications related to femoral vessel cannulation, such as arterial injury requiring reconstruction, retrograde aortic dissection, atheroembolism, limb ischemia, delayed wound healing, and groin infection, are avoided [4].
In addition, standard transthoracic aortic cross-clamping and antegrade cardioplegia delivery obviate the need for specialized endovascular occlusive balloons, thus reducing the surgical cost and avoiding potential complications associated with balloon malposition or migration [6].
This surgical approach through both the third and fourth intercostal space combines a good cosmetic result with good exposure to the mitral apparatus. It does not require sacrifice of the internal mammary artery [1]. It is readily applicable and is not associated with a steep learning curve, because one employs conventional cannulation and clamping techniques. When compared with the port-access technique, the slightly longer incision required for the technique we describe is outweighed by the absence of a groin incision for femoral cannulation, multiple additional skin incisions for the other cannulas [4, 5] or the aortic clamp [3], and the additional risk of groin cannulation. Lastly, the cost of this approach is consistent with standard costs for cardiopulmonary bypass, and in our experience, has permitted patients to return to a normal lifestyle more quickly than that of a median sternotomy approach.
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References
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Navia J.L., Cosgrove D.M. Minimally invasive mitral valve operations. Ann Thorac Surg 1996;62:1542-1544.[Abstract/Free Full Text]
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Lin P.J., Chang C.H., Chu J.J., et al. Video-assisted minimally invasive mitral valve operations. Ann Thorac Surg 1996;61:1781-1787.[Abstract/Free Full Text]
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Chitwood W.R., Jr, Elbeery J.R., Chapman W.H.H., et al. Video-assisted minimally invasive mitral valve surgery: the "micro-mitral" operation. J Thorac Cardiovasc Surg 1997;113:413-414.[Free Full Text]
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Glower D.D., Komtebedde J., Clements F.M., Debruijn N.P., Stafford-Smith M., Newman M.F. Direct aortic cannulation for port-access mitral or coronary artery bypass grafting. Ann Thorac Surg 1999;68:1878-1880.[Abstract/Free Full Text]
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Mishra Y.K., Malhotra R., Mehta Y., Sharma K.K., Kasliwal R.R., Trehan N. Minimally invasive mitral valve surgery through right anterolateral thoracotomy. Ann Thorac Surg 1999;68:1520-1524.[Abstract/Free Full Text]
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Grocott H.P., Smith M.S., Glower D.B., Clements F.M. Endovascular aortic balloon clamp malposition during minimally invasive cardiac surgery: detection by transcranial doppler monitoring. Anesthesiology 1998;88:1396-1399.[Medline]
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Abstract
Introduction
