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ORIGINAL ARTICLE |
Department of Cardiovascular and Thoracic Surgery, Viet Duc University Hospital, Hanoi, Vietnam
Nguyen Huu Uoc, PhD, Tel: +84 0903239788, Fax: +84-4-38248308, Email: uocdhyhn101{at}yahoo.com.vn, Department of Cardiovascular and Thoracic Surgery, Viet Duc University Hospital, Hanoi, Vietnam.
ABSTRACT
In mitral valve surgery, the combined superior-transseptal approach gives excellent exposure of the mitral valve, but it is lengthy and complex. A modified version of this approach was made without cutting the right atrial appendage and the dome of the right atrium. This shorter procedure was evaluated in 30 patients aged 4–61 years undergoing complex mitral valve operations including mitral repair (33.3%), reoperation (30%), and small left atrium (30%). The mitral valve was exposed well in all cases. Because of the shorter incision, closure was relatively easy. The aortic crossclamp time was 117 ± 29.9 min (range, 53–173). There were no major complications. Cardiac rhythm resumed spontaneously after release of the aortic clamp in 93.3% of patients, including 36.7% who regained sinus rhythm from arrhythmia preoperatively. There was no heart block, bleeding, or mortality. Results at 3 months were good. Despite a decreased operative field, this modified approach provided adequate exposure for all the required techniques. The benefits of this approach are a shorter incision in the atrial muscle, and simplified closure technique.
Key Words: Cardiac Surgical Procedures • Heart Valve Prosthesis Implantation • Mitral Valve
INTRODUCTION
In mitral valve surgery, there are various approaches to the left atrium (LA) to expose the mitral valve apparatus, including the classic vertical interatrial groove approach, vertical transatrial septal, LA roof, and classic approach extended to the LA roof with temporary division of the superior vena cava. In 1991, Berreklouw and colleagues1 and Guiraudon and colleagues2 proposed a combined superior-transseptal approach to create a larger operative field, closer to the mitral valve (Figure 1
). Having applied this approach since 1993, we found that although the mitral valve is well exposed, the long incision requires a complex closure process and prolonged aortic crossclamping. In June 2004, we shortened this approach by omitting to cut the right atrial appendage and lateral aspect of the right atrium (Figures 2 and 3). This study was performed to evaluate the effects of this shorter approach.
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Thirty patients who underwent isolated mitral valve procedures or combined mitral and other valve operations at Viet Duc Hospital from June 2004 to June 2007 were prospectively enrolled in the study. There were 12 (40%) males and 18 (60%) females with a mean age of 36.4 ± 15.5 years (range, 4–61 years). There were 9 cases of reoperation (30%). The mean diameter of LA was 53.9 ± 14.7 mm (range, 29–97 mm); 9 (30%) patients had LA diameters <45 mm. Twenty (66.7%) patients had rheumatic valve disease, and 15 (50%) had atrial fibrillation.
A modified LA approach was applied to expose the mitral valve (Figure 2
). Three incisions were carried out: the 1st incision was made vertically on the anterolateral aspect of the right atrium, parallel to the atrioventricular groove, from the base of the inferior vena caval cannula to the root of the right atrial appendage. The 2nd incision was made vertically on the transatrial septum, from the base of the inferior vena cava to the middle of the right atrial roof. The 3rd incision extended the 2nd incision 2–3 cm to the LA roof, and forward to the root of the LA appendage. The mitral valve was exposed using 1 or 2 small retractors attached to the left edge of the atrial approach, and/or 2 suspension sutures on the left edge in more difficult cases. The LA was closed with 2 polypropylene 4/0 sutures, starting from the 2 sides of the incision with simple continuous sutures, and then in 2 planes on the incision of the LA roof. The tie was in the middle of transatrial septal incision. The right atrial incision was closed normally.
RESULTS
The mitral valve was easily exposed in all cases, and no additional interventions were required (Figure 3). Cardiac rhythm resumed spontaneously after releasing the aortic crossclamp in 93.3% of patients; 3 (10%) required pacing due to bradycardia, and 11 (36.7%) converted from preoperative dysrhythmia to sinus rhythm. Six (20%) patients who had preoperative arrhythmias maintained sinus rhythm until discharge from the hospital, 3 required temporary pacing for 24 h after the operation. Operative details are given in Table 1. Aortic crossclamp time was not prolonged in the 33.3% of cases requiring mitral valve repair (Table 2). There were no cases in which sinus rhythm was lost, and there were no new arrhythmias or bleeding requiring reoperation related to this approach. The mean stay in the intensive care unit was 4.1 ± 3.0 days (range, 2–17 days), and total hospitalization was 11.8 ± 10.2 days (range, 3–56 days). Prolonged hospitalization was due to infection. There was no operative mortality. After 3 months, 25 (83.3%) patients were available for follow-up by clinical examination and transthoracic echocardiography. There were no arrhythmias (sinus insufficiency or conversion from preoperative sinus rhythm to postoperative arrhythmia), nor any other complication involving the approach to the LA (atrial septal defect).
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In mitral valve surgery, the approach to LA influences the quality of the operation, especially in difficult anatomical situations such as a small LA, pericardial adhesions in reoperations, a deep thorax, dilated right cardiac chambers, or technically difficult operations including mitral valve repair.1–10 The combined superior-transseptal approach facilitates improved expose to the mitral valve apparatus in these situations. However, in our experience, this approach has drawbacks including large incisions cutting long sections of atrial muscle, and a complex closure process. Other studies have shown the effects of this approach on sinus node function and postoperative arrhythmias.6–8 The modified LA approach avoids these problems, presumably by protecting a significant portion of atrial muscle.
The age of the patient is an important factor in postoperative arrhythmias after mitral valve surgery.9 The mean age (36.4 years) in this study was similar to that of other Vietnamese studies (35–36 years) that included children (the youngest child in our series was 4-years old). The incidence of arrhythmia is rather high (50%) but similar to other studies (56%–59%).1,2,9,10 Arrhythmias influence the quality of operations, therefore, one criterion of mitral valve surgery via the atrial approach is reestablishing and maintaining sinus rhythm postoperatively. The incidence of reoperations was 30% in our series, similar to others (26%–40%).1,2,9,10 LA diameter is an important factor in choosing an atrial approach; 30% of our patients had a small atrium, similar to other studies (25%–35%).9,10 All preoperative characteristics, especially the incidence of difficult anatomical forms, were similar to previous studies.
This modified approach does not cut through the right atrial appendage and part of the right atrium, therefore, although it may damage the superior right atrial artery (one blood source for the sinus node) and bundle branches, it can better nourish the sinus region from the collateral system around the sinus node, and increase the number of atrial muscle fibers that connect the sinus node with the atrioventricular node, thus reinforcing sinoatrial conduction.1–5,9,10 Our results showed that although the operative field was smaller than that of the classic approach, the modified approach was always closer to the edge of the mitral valve, so its exposure was relatively simple in all cases. Furthermore, closure after this approach was much simpler than after the classic approach. As for the LA roof incision, we still closed the incision in 2 planes to prevent bleeding complications when the heart resumed beating.2 Otherwise, operative concerns with the improved approach were similar to those of the classic approach and met all the criteria for mitral valve surgery.9 The indications for the shorter approach are similar to those of the classic approach, and it is advantageous in the situation of difficult anatomical forms (pericardial adhesions in reoperations, LA diameter <45 mm, deep thorax, dilated right cardiac chambers), combined tricuspid valve disease, mitral valve repair, and mitral valve surgery in children.
Presented at the 18th Biennial Congress ATCSA, Bali Indonesia, November 25–28, 2007.
REFERENCES
Asian Cardiovasc Thorac Ann 2009;
17:171-174
© 2009 by SAGE Publications
DOI: 10.1177/0218492309103308
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