Ann Thorac Surg 1996;61:1265-1266
© 1996 The Society of Thoracic Surgeons
How To Do It
Transatrial Atrioventricular Valve Testing in the Beating, Fully Loaded Heart
Alfonso-Tadaomi Miyamoto, MD
Research Department, Kokura Memorial Hospital, Kitakyushu-shi, Japan
Accepted for publication October 18, 1995.
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Abstract
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A detailed technique is described to safely inspect visually the function of the atrioventricular (mitral, common atrioventricular, or tricuspid) valve in the beating, fully loaded, but not ejecting left or right ventricle. The heartbeat is reestablished while the ascending aorta is kept cross-clamped and air from the ascending aorta is vented out. The left or right ventricle is filled via a 6-mm internal diameter tube derived from the arterial return line. To allow filling of the right ventricle for tricuspid valve evaluation, the pulmonary artery is snared down in addition.
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Introduction
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Determination of the competence of the repaired mitral valve while the left atrium is still open is an imprecise matter, and for simplicity it is usually done by instilling saline solution into the left ventricular (LV) chamber with a bulb syringe in the nonbeating, either flaccid or fibrillating heart to avoid air embolization. In the great majority of patients this technique provides adequate evaluation, as is stated in Kirklin and Barratt-Boyes' textbook [1]. However, proper evaluation of valve function requires a beating, fully loaded heart, which generally means waiting for either conventional postoperative Doppler or intraoperative Doppler transesophageal [2] or epicardial echographic evaluation after weaning the patient from cardiopulmonary bypass (CPB), or postoperative ventriculographic studies.
Here I describe a technique to allow direct, transatrial, visual evaluation of the valve in the fully loaded, beating heart without incurring the risks of air embolization.
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Technique
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The heartbeat is reestablished while the ascending aorta is kept cross-clamped by perfusing warm CPB blood without potassium additive into the proximal ascending aorta [3] via the cardioplegic circuit, making sure that the apex of the dome of the cross-clamped ascending aorta is properly vented to allow air to exit [4] (Fig 1
). If crystalloid cardioplegia is being used, a side arm from the CPB arterial line or the LV filling line with a no. 14 to 16 needle at its tip could be used to provide the coronary blood flow requirements. If retrograde blood cardioplegia is being used, it is assumed that perfusion with blood without potassium additive should be equally effective to reestablish the beat for a sufficient time to allow the testing, because full cardiac output support for an unlimited time is not necessary.
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Fig 1. . Schematic representation of the technique. The left ventricular (LV) filling line derived from the arterial return line is introduced into the LV chamber, and the LV is allowed to fill. The LV filling line is clamped and withdrawn toward the left atrium (LA), while the mitral valve (MV) is inspected with the heart beating and the LV fully loaded but not ejecting by having the aorta cross-clamped and any air vented out from the top of the dome of the ascending aorta (Ao). (ACC = aortic cross-clamp; Art = Arterial; BCP = blood cardioplegia administration needle, which is tied and secured onto the ACC; SPV and IPV = superior and inferior pulmonary veins; SVC can and IVC can = superior and inferior vena caval cannulas.)
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For adequate volume loading, a segment of tube with 6-mm internal diameter is derived from the arterial return (or from the arterial side of the arteriovenous shunt line) of the CPB circuit. The tip of this side arm tube is introduced into the LV chamber via the mitral (common atrioventricular) leaflets, which allows filling of the systemic or LV with blood from the CPB circuit, regardless of its capacity, in a very short time, which often a bulb syringe can not do. Once the LV is filled, the tube is clamped and withdrawn from the ventricular chamber (see Fig 1
). Because more often than not these kind of patients with atrioventricular valve regurgitation also have an enlarged left atrium, exposure without causing distortion of the aortic or mitral (or common atrioventricular) valve offers no problems, and the repaired atrioventricular valve can be visually inspected at leisure. The LV can be refilled as many times as needed from the atrial side while the heart is beating full, although not ejecting. The atrial view of the closed valve not only gives visual information as to the presence or absence of regurgitation but also allows making technical judgments as to how and where to add repairing efforts if need be, which transesophageal or epicardial echographic evaluation could not provide.
The aorta must be kept cross-clamped at all times to avoid air embolization. In the beating heart with the left atrium open and empty, some air will appear in the ascending aorta regardless of how carefully the LV is filled, which also implies the need for continuously supplying blood to the coronary arteries with a pump (the same pump used for the administration of the blood cardioplegic mixture, but without the cardioplegic additives or the arterial pump of the CPB) and an air venting port made at the highest portion of the dome of the cross-clamped ascending aorta [4], which is allowed to bleed freely or could be connected to one cardiotomy suction line (see Fig 1). A myocardial pacing wire is used to drive the heart at an adequate rate, so the testing can be performed without having to wait for full rewarming if hypothermia had been induced.
To evaluate objectively the pressures to which the atrioventricular valve is being subjected, the developed or systolic LV pressure (which should be a function of the LV preload or degree of filling) information can be indirectly obtained via the aortic root pressure monitoring port of the cardioplegic administration needle (Fig 2). Although flaccid and beating heart conditions were not statistically compared, occasionally a seeping leakage in the flaccid heart makes it impossible to fill the ventricle with a bulb syringe, but when the heart is reevaluated with adequate filling under beating conditions as described, a totally competent valve can be appreciated. Even though the heart is not normally loaded, this technique permits leaflet closure mechanisms to operate as close to normal as possible.
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Fig 2. . Pressures obtained at the aortic root permit evaluation of the systolic pressure to which the mitral valve is being subjected, ie, left ventricular developed pressure (which is a function of left ventricular filling), unobstructed by catheters across the valve in the operative field. Note that the systolic pressure exceeds by far the patient's normal systolic pressure, and the scale of the recording had to be changed.
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Comment
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Because this technique allows identification of the exact location and nature of the residual leaks, measures to correct them can be implemented, if necessary, before the left atriotomy is closed, thus obviating the need for weaning the patient off CPB, which transesophageal or epicardial echographic evaluation requires. The technique has been employed in the evaluation of close to 100 patients without complications ascribable to air embolization. It is essentially a byproduct of blood cardioplegia, and by filling the LV with a line derived from the arterial return, it allows rapid filling of the LV with CPB blood, thus avoiding unnecessary fluid loading.
Ideally the tricuspid valve should be evaluated with both ventricles full. However, generally only the right ventricle is filled, for which the pulmonary artery is clamped or snared down with a tourniquet while the right ventricle is filled as described by inserting the tube derived from the arterial return line in the right ventricular chamber via the tricuspid valve orifice. Annuloplastic sutures [5, 6] could be adjusted to the appropriate length and temporarily secured during valve testing. Once adequate competence of the valve is demonstrated, the sutures are tied definitively, perhaps even after additional suturing of the leaflets was performed had it been needed.
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Footnotes
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Address reprint requests to Dr Miyamoto, Research Department, Kokura Memorial Hospital, 1-1 Kifunecho, Kokura-kitaku, Kitakyushu-shi, Japan 802.
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References
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- Kirklin JW, Barratt-Boyes BG. Mitral valve disease with or without tricuspid valve disease. In: Kirklin JW, Barratt-Boyes BG, eds. Cardiac surgery. 2nd ed. New York: Churchill Livingstone, 1988:323–72.
- Reichert SLA, Visser CA, Moulijn AC, et al. Intraoperative transesophageal color-coded Doppler echocardiography for evaluation of residual regurgitation after mitral valve repair. J Thorac Cardiovasc Surg 1990;100:756–61.[Abstract]
- Yacoub M, Halim M, Radley-Smith R, McKay R, Nijveld A, Towers M. Surgical treatment of mitral regurgitation caused by floppy valves: repair versus replacement. Circulation 1981;64(Suppl 2):210–6.
- Miyamoto AT. Technique for replacing the ascending aorta and aortic valve with a modified Bentall's operation. Ann Thorac Surg 1992;53:1125–6.[Abstract/Free Full Text]
- De Vega N. La anuloplastia selectiva permanente. Rev Esp Cardiol 1972;25–6.
- Nakano S, Kawashima Y, Hirose H, et al. Evaluation of long-term results of bicuspidalization annuloplasty for functional tricuspid regurgitation. A seventeen-year experience with 133 consecutive patients. J Thorac Cardiovasc Surg 1988;95:340–5.[Abstract]
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[Abstract]
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Abstract
Introduction
