For degenerative mitral disease of the posterior mitral leaflet, a sliding leaflet plasty is often recommended1–3 to correct large areas of prolapse and to reduce posterior leaflet height to avoid systolic anterior motion (SAM).4,5 However, this complex procedure is lengthy and technically challenging, especially when using most minimally invasive approaches. As an alternative, using a robotic endoscopic approach, multisegment triangular resection produces an approach that is quicker, simpler, and yet just as effective as that of conventional quadrangular resection and sliding leaflet plasty.
A 56-year-old man presented with mild dyspnea on exertion and palpitations. Transesophageal echocardiography (TEE) revealed severe mitral regurgitation (MR) with diffuse prolapse of P2 with thickened leaflets and an eccentric anterior jet. There was also a separate interscallop jet between P1 and P2. The three-dimensional TEE revealed P2 prolapse as well as excessive height of P2 and P3, thus predicting a high likelihood of SAM. The ejection fraction was 60%, with no segmental wall abnormalities.
With the patient in the supine position under general double-lumen anesthesia, bilateral radial arterial lines, a Swan-Ganz catheter, and an Endoplege (Edwards Lifesciences, Irvine, CA USA) retrograde cardioplegia cannula were placed by anesthesia. A 12-mm camera port was made in the right fourth intercostal space just lateral to the nipple. Through a side port of the camera port, heated CO2 was continuously infused. An 18-mm service port was made in the same intercostal space 4 cm laterally. Next, 14-gauge angiocatheters for the diaphragmatic and pericardial stay sutures were placed and capped so as to prevent the egress of CO2 from the chest. Finally, three 8-mm trocars were placed for eventual insertion of the robotic arms.
The patient was systematically heparinized. A 4-cm incision was carried out in the right groin. The anterior surface of the common femoral artery and vein was exposed. Through purse strings of 5-0 Prolene using the Seldinger technique, a long femoral venous cannula was directed into the superior vena cava under TEE control. An additional 5F angiocatheter was directed into the superficial femoral artery to provide distal perfusion of the leg during the pump run. A 23F Endoreturn (Edwards Lifesciences, Irvine, CA USA) aortic cannula was inserted. All tubing was connected. Under TEE control, an Endoballoon (Edwards Lifesciences, Irvine, CA USA) was passed over a J-wire into the aortic root. The patient was then docked with the robot.
After docking, a 2-0 Gore-Tex was placed in the tendinous portion of the right hemidiaphragm to provide traction for retracting the diaphragm out of the operating field and to minimize the risk for hepatic injury. The pericardium was then opened from the inferior vena cava to the pericardial reflection of the distal ascending aorta and suspended with two 4-0 pericardial Gore-Tex stay sutures.
The patient was then placed on cardiopulmonary bypass. After achieving stable pressures on bypass, the Endoballoon was inflated, and antegrade cardioplegia was administered through the distal port. Subsequent doses of cardioplegia were given every 20 minutes via the retrograde cardioplegia cannula.
A standard vertical left atriotomy was carried out, revealing the mitral valve. Intraoperative findings were consistent with the preoperative echocardiogram. Valve analysis revealed advanced mitral degenerative disease of the posterior leaflet, which was thickened and enlarged. There was a very large prolapsing P2 segment as well as an indentation between P1 and P2. The nonprolapsing P3 segment was also enlarged (Fig. 1A).
The first maneuver was to close the indentation between P1 and P2 by intracorporeal tying of a figure-of-eight suture (Fig. 2A) with a 4-0 Cardionyl (Cardionyl; Peters Laboratories, Bobigny-Cedex, France). Attention now focused on elimination of the P2 prolapse as well as height reduction of the P2 and P3 segments. Instead of the traditional sliding leaflet plasty, we opted for multisegment triangular resection. A generous triangular resection of P2 was carried out (Fig. 1B). A sturdy secondary P2 chord in the resected specimen was transferred to the edge of the P2 remnant with a 4-0 Cardionyl (Fig. 2B). After completing the chordal transfer, the remainder of the leaflet of the P2 segment was resected and removed from the field. The P2 remnant was then reconstituted with two rows of running 4-0 Gore-Tex.
Using the Lawrie technique, a saline test was carried out with a laparoscopic saline insufflator.6 The saline test demonstrated proper proportionate height at the P2 segment without prolapse, but P3 remained much too tall in the septal-lateral dimension, resulting in an unfavorable closure line at P3 (Fig. 2C). Neglected, this anatomy would likely lead to the development of SAM. Thus, another triangular resection was carried out to reduce the height of P3 (Fig. 2D). After completing this resection, the remnant of P3 was reconstituted in the same way as P2, with two layers of running 4-0 Gore-Tex. The saline test now displayed a symmetric line of closure, with normal anterior to posterior dimensions in the septal-lateral aspect, eliminating the likelihood of SAM.
The anterior leaflet was unfurled, the annulus was sized, and a 39-mm ATS band (ATS Medical, Inc, Minneapolis, MN USA) was selected. While warming systemically, an annuloplasty band was then secured along the posterior annulus from trigone to trigone using U-clips (Medtronic Inc, Minneapolis, MN USA; Fig. 1C). The saline test demonstrated a symmetric line of closure, with the posterior leaflet height comprising 20% of the septal-lateral dimension (Fig. 2E).
After completing the mitral repair, the sump was then placed across the valve orifice. The atriotomy was then closed with running continuous 4-0 Gore-Tex. Before completing this suture line, the Endoballoon was deflated after filling the left side of the heart. At no time was there any air ever seen on the left side of the heart by TEE. The suture line was tied and noted to be hemostatic. Careful hemostasis was obtained in the hemithorax before undocking the robot. The stay sutures were then removed, and the right lung was gently reinflated for a period of 5 minutes. The patient was then weaned from cardiopulmonary bypass on 5 μg/kg per minute of dobutamine.
The postoperative echocardiogram revealed no SAM, normal velocities in the left ventricular outflow tract, no MR, and a large zone of coaptation. The desired 80:20 ratio of the anterior and posterior leaflets in the septal-lateral dimension was demonstrated by three-dimensional image reconstruction. There was also evidence of a reduction in size of the left ventricle. The patient’s postoperative course was smooth, and he was discharged home on the third postoperative day. Fifteen months postoperatively, a transthoracic echocardiogram revealed no residual MR and normal left ventricular function.
Aside from restoring valvular competency in advanced mitral degenerative disease, a major goal of mitral valvular reconstruction is the restoration of a normal height ratio between the anterior and the posterior leaflet in the septal-lateral dimension. The final height of the posterior leaflet should be between 10% and 30% of this dimension. Altering this ratio in a way that leads to a large posterior leaflet will often result in SAM because the anterior leaflet is pushed into the left ventricular outflow tract by the excessively tall posterior segment.4,5 There are two schools of thought in managing excessive posterior leaflet height: resection and nonresection.
The attitude of “respect, rather than resect,” as advocated most prominently by Perier et al,7 reduces the height of the posterior leaflet by pulling the leaflet edge into the ventricle. This is accomplished by Gore-Tex neochords anchored in the fibrotendinous portions of the papillary muscles, which results in a posterior leaflet that is “verticalized” and parallel to the lateral ventricular wall. However, extremely large posterior leaflets can still be unacceptably tall even after drawing the leaflet edge all the way to the origin of the neochord in the papillary muscle tip. Unless the neochord is anchored close to the base of the papillary muscle, SAM may still occur. In addition, a potential disadvantage of anchoring a neochord toward the base of the papillary muscle is the relative lack of fibrous tissue, possibly rendering the neochord more likely to avulse. Clearly, extreme cases of mitral degenerative disease require the surgeon to at least have the option of resecting an excessive posterior leaflet.
Managing multisegment advanced degenerative mitral disease of the posterior leaflet by resection has traditionally been accomplished by sliding leaflet plasty.1–3 Usually, a quadrangular resection of P2 is followed by detaching P1 and P3 from the annulus and advancing the segments to cover the annular territory formerly occupied by the unresected P2. If necessary, to restore the proper anterior-posterior height ratio, wedge resection of P1 and/or P3 parallel to the annulus can also be carried out. To reduce the annular distance that must be covered by P2 and P3, horizontal and/or vertical compression sutures are often placed before reattaching the posterior leaflet remnant. These compression sutures are often difficult to place, particularly with minimally invasive approaches. In addition, these can potentially distort or injure the underlying circumflex artery.
Of note, at the time this procedure was done, we used U-clips to secure the annuloplasty band to the posterior annulus. Subsequently, U-clips were withdrawn from the market. We now use interrupted horizontal mattress 2-0 Ethibond (Johnson and Johnson, New Brunswick, NJ USA) secured with Cor-Knot (LSI Solutions, Victor, NY USA) fasteners to install the band as a very satisfactory substitute for U-clips. Regardless of the technique used to stabilize the posterior annulus, the focus of this report is to relate an effective substitute for sliding leaflet plasty.
The technique of multisegment triangular resection is capable of accomplishing the same goals as those of sliding leaflet plasty by resecting prolapsed segments and restoring the normal septal-lateral height ratio. In addition, the use of the triangular resection technique is technically much simpler than sliding leaflet plasty,8,9 and the lack of compression sutures lessens the possibility of circumflex artery kinking or injury because the annulus is never distorted. The motorized laparoscopic irrigator proves particularly helpful in multisegment triangular resection because frequent use of the saline test can guide where and how many resections are necessary. Multisegment triangular resection is particularly appealing in robotic cases when the table-side assistant is often inexperienced in reliably tying the compression sutures integral to sliding leaflet plasty. We have also incorporated this technique in some of our nonrobotic cases because of its expeditious and reliable results. Our experience in multisegment triangular resection has validated this procedure as a viable addition to the armamentarium of repair techniques available for a mitral valve surgeon.
The authors thank Ms Elissa Powers and Mr Jeremy Coley for their administrative support.
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