A Simple Method to Prevent Calcium Embolization during Aortic Valve Surgery

Abstract

Calcium embolization is a potential complication of aortic valve surgery. Handling and débridement of calcified structures may lead to dislodgment of particles, which can fall into the left ventricular chamber. With restoration of the heartbeat, these particles are ejected into the systemic circulation, with subsequent peripheral or coronary embolism. We have developed a simple and safe method to prevent this condition; in our practice, we have found this method to be very effective. (Tex Heart Inst J 2001;28:320–1)

Calcium embolization is a recognized complication of aortic valve operations. ^1–4 The true incidence of calcium embolization during or immediately after open-heart surgery is unknown, since movement of emboli to areas other than the heart, brain, or kidneys is usually asymptomatic.

Careful suction of débris by the surgeon's assistant is generally used to prevent such complications. Alternatively, surgical gauze, irrigated with saline, is placed in the left ventricle after valve excision and before further removal of calcium from the aortic annulus. The major limitations of this technique are that 1) it offers protection only during annulus débridement and not during the valve excision, 2) it requires removal of the gauze before the valve is seated, 3) it can hide small loose fragments that might embolize when the gauze is removed, and 4) the gauze may obstruct both the field of vision and the actual removal of calcifications that extend into the base of the anterior mitral valve leaflet. In 1968, Ibarra-Perez and Lillehei ^1,2 described a device to prevent calcium embolization, which inspired us to develop this new method.

Technique

The aortotomy is made and cold cardioplegic solution is injected into the coronary ostia. Then a large (16- or 18-F) Foley catheter is inserted through the aortic valve orifice, followed by gentle insufflation with normal saline solution. We use a large catheter to ensure contact with the left ventricular outflow tract but not with the annulus (Fig. 1). The lumen of the catheter is connected to a suction line to vent the left ventricle. This decompresses the left ventricle during valve excision. The catheter is then partially retracted, allowing an optimal view of the valve structures, elevating the annulus, and facilitating resection of the valve. The loose fragments are confined to a limited space from which they can be removed easily by suction. The catheter is left in place while sutures are placed in the annulus, since this procedure can loosen calcium particles. After careful removal of all débris and abundant flushing, the catheter is deflated and the valve is seated. The deflated catheter is then passed through the valve for left ventricular venting.

Fig. 1 Drawing shows the balloon catheter in the left ventricular outflow tract. The balloon is not in contact with the annulus, which allows resection of the valve leaflets, a clear view of the anterior mitral leaflet, and the placement of sutures.

Comment

In 1968, Lillehei's group ¹ described an instrument designed to prevent calcium embolization. It was shaped like an umbrella with a metallic handle, and it was used successfully in clinical practice for years. ² Our method is a simplified version of their technique, and it has been performed in more than 300 aortic valve procedures at our institution. Since its introduction in 1997, we have not had any embolic complications; neither has there been any complication related to the technique. This method of preventing calcium embolization has been shown to be very useful in conjunction with abrasion or ultrasonic débridement techniques, ⁵ which can produce particularly insidious micronized calcium particles. Furthermore, the catheter provides an excellent view of the surgical field, and its presence does not hamper surgical maneuvers.