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Ann Thorac Surg 2004;77:2157-2162
© 2004 The Society of Thoracic Surgeons

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Original article: cardiovascular

Left atrioventricular valve regurgitation after repair of incomplete atrioventricular septal defect

^a Department of Cardiovascular Surgery, Hokkaido University School of Medicine, Sapporo, Japan

Accepted for publication December 2, 2003.

^* Address reprint requests to Dr Murashita, Department of Cardiovascular Surgery, Hokkaido University School of Medicine, Kita-14, Nishi-5, Kita-ku, Sapporo 060, Japan
e-mail: muratosh{at}med.hokudai.ac.jp

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
BACKGROUND: Excellent surgical results have been reported for repair of incomplete atrioventricular septal defect; however, left atrioventricular valve regurgitation (ltAVVR) is a major cause of late morbidity. We reviewed our entire experience with incomplete atrioventricular septal defect in order to investigate long-term results of ltAVVR after repair and determine the factors influencing the progression of ltAVVR in late follow-up.

METHODS: Between 1983 and 2002, 61 patients underwent surgical repair of incomplete atrioventricular septal defect, including 7 patients with intermediate forms. The age of operation ranged from 1 month to 62 years old (median 5.3 years old). Thirteen patients were less than 2 years old, including 7 infants, while there were 15 adult patients. All patients underwent patch closure of the ostium primum defect. Before 1995, the cleft was left open in 7 patients and partial closure of the cleft was done in 41 patients, whereas complete closure of the cleft was performed in 9 patients since 1996. Preoperative and postoperative ltAVVR at hospital discharge and late follow-up were graded 0–IV by echographic evaluation.

RESULTS: There was 1 early death and 4 late deaths with a 91% 10-year actuarial survival rate. Preoperative ltAVVR grade was I in 25 patients, II in 31 patients, III in 4 patients, and IV in 1 patient. Postoperatively, ltAVVR deteriorated in 3 patients. Left AVVR decreased in 21 patients, whereas in 37 patients it remained the same at hospital discharge. Consequently, ltAVVR remained grade II in 18 patients, grade III in 2, and there was no patient with grade IV. During the long-term follow-up, 24 patients were noted to have increased ltAVVR, including grade III in 8 patients and grade IV in 4. Reoperations for ltAVVR were required in 5 patients (8.3% of hospital survivors); valve replacement in 3 patients and valve repair in 2. Actuarial freedom from reoperation for ltAVVR was 91% at 10 years, whereas actuarial freedom from postoperative ltAVVR grade III or more was 89% at 5 years and 78% at 10 years. Multivariate analysis indicated that postoperative ltAVVR grade II or more at hospital discharge (p = 0.0032, odds ratio = 7.41, 95%CI: 1.95–28.10) was the only independent variable related to late ltAVVR, whereas age at operation, preoperative grade of ltAVVR, and the method of cleft repair were not significant risk factors.

CONCLUSIONS: Left AVVR is still a significant risk in long-term follow-up. Because the postoperative grade of ltAVVR is the only independent risk factor for late ltAVVR, more efforts should be focused on left atrioventricular valve repair so as to minimize residual regurgitation, even mild regurgitation.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
Incomplete or partial atrioventricular septal defects (AVSD) are characterized anatomically by the presence of an ostium primum atrial septal defect occupying the portion of the atrial septum just superior to the separately formed tricuspid and mitral valves. In this anomaly, the terms left atrioventricular (AV) valve and right AV valve are preferred to mitral and tricuspid valve, respectively, and varying degrees of clefting of the anterior leaflet of the left AV valve are present. Surgical repair of uncomplicated incomplete AVSD is, for the most part, simple and yields generally good results, except in specific conditions [1, 2]. Late death after repair of incomplete AVSD is rare, occuring in 0% to 4% of patients [3–5]; however, as with complete AVSD, left AV valve regurgitation (ltAVVR) is the major cause of late morbidity after repair of incomplete AVSD. Recent reports have indicated that reoperation for significant regurgitation is required in 3% to 13% of patients after repair of incomplete AVSD [2, 6–8]. Repair during infancy [1, 9] and unsutured cleft [3, 10, 11] are reported to be risk factors influencing late ltAVVR. In this report we present a review of our entire experience with incomplete AVSD in order to investigate long-term results of ltAVVR after repair and determine the factors influencing the progression of ltAVVR in late follow-up.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
Sixty-one patients underwent surgical correction of incomplete AVSD between April 1983 and April 2002. Seven patients with intermediate forms were included, whereas patients with the complete form of AVSD were excluded. Intermediate forms of AVSD were those with a small ventricular septal defect (VSD) associated with a two-valve orifice and with a cleft of the left AV valve leading to use of a surgical approach similar to that used for patients with incomplete forms. There were 36 female and 25 male patients. The age of operation ranged from 1 month to 62 years old (median 5.3 years old). There were 13 patients less than 2 years old, including 7 infants (< 1 year old), and 15 adults more than 15 years old. Associated cardiovascular anomalies were present in 9 patients: 2 patients with partial anomalous pulmonary vein connection; 2 patients with patent left superior vena cava; 3 patients with vavular pulmonary stenosis; 1 patient with a double orifice mitral valve; and 1 patient with left ventricular outflow stenosis. Three patients had Down's syndrome, and one had Ellis-van Creveld syndrome. There were 4 adult patients with atrial fibrilation and significant right AVVR. Cardiac catheterization data, echocardiograms, and operative and hospital records were reviewed for all patients. All were followed up either at our outpatient clinic or at other cardiac centers. Data were collected from pediatric cardiologists who took care of the patients, and telephone calls were made and questionnaires sent to patients for further data collection when necessary. Preoperative and postoperative ltAVVR for both hospital discharge and late follow-up were evaluated. Left AVVR was graded 0–IV by angiographic or echographic evaluations [12]. The follow-up period ranged from 1 to 20 years (mean, 8.8 ± 5.2 years).

Surgical methods
Standard cardiopulmonary bypass with mild-to-moderate hypothermia was used for repair in all patients, and no circulatory arrest was used in any case. Until 1991, myocardial protection was achieved with the aid of multidose cold crystalloid cardioplegic solution, administered in the antegrade manner. Since 1992 this has been replaced by the use of cold blood carioplegic solution. The mean cardiopulmonary bypass time was 111 ± 41 minutes (range, 62 to 203 minutes), while the mean aortic clamp time was 61 ± 26 minutes (range, 44 to 122 minutes).

The ostium defect was closed with a fresh autologous pericadial (n = 39), a heterogenous pericardial (n = 15) or Dacron (n = 7) patch. The coronary sinus was left on the right or left side of the patch in 34 and 27 patients, respectively. For 2 patients with PLSVC, the coronary sinus was left on the right side. The methods of cleft repair depended on the surgeon's preference before 1995, during which time complete closure of the cleft was not performed intentionally. Thus, the cleft was not present in 2 patients, while it was left open in 7 patients and partially closed in 41 patients. However, since 1996 complete closure of the cleft, from the annulus to the leaflet margin where the free edge of the cleft attaches to the major chordae, was performed intentionally in 9 patients. Interupted 6-0 or 5-0 monofilament sutures were used to close the cleft using the rolled edge, thereby avoiding the opposing surfaces of the leaflet. Intraoperative assessment of status of regurguritation was done with saline distention of the left ventricle, thereby floating the leaflets, and doing a careful anatomic and functional evaluation. In paticular, since 1996, a need for annuloplasty was felt in 2 patients and Kay annuloplasty was carried out in both of these patients. Four adult patients required repair of the right AV valve by DeVega's annuloplasty because of significant right AVVR.

Associated procedures were done in 13 patients. In the 7 patients with intermediate forms, the VSD was closed directly with monofilament sutures. A modified Maze procedure was performed in 2 adult patients with atrial fibrillation, whereas 1 patient required pacemaker implantation due to bradycardia. In a patient with a double-orifice left AV valve, the cleft and accessory orifice were left open. For 2 patients with associated PAPVC, the suture line of the patch was made so as to connect all pulmonary veins to its left side, while 2 patients with pulmonary valvular stenosis had valvotomy only. In 1 patient with left ventricular outflow stenosis no procedure was performed because of mild stenosis with a pressure gradient of 30 mm Hg.

Statistical methods
The data were analyzed using StatView for Macintosh (Version 5.01; SAS Institute, Inc, Cary, NC). Time-related analyses of survival and freedom from ltAVVR grade III or more were performed with the Kaplan-Meier method. The log-rank test was used for statistical analysis and p values of less than 0.05 were considered significant. For multivariate analyses, we used the Cox regression model with risk factors that were significant or those with p values of less than 0.1 obtained by univariate analysis. The data are presented as the mean ± standard deviation, and proportional data are presented with their 95% confidence intervals (CI).

	Results

Top Abstract Introduction Patients and methods Results Comment References

 
Mortality
There was one early death after repair of incomplete AVSD in the early part of this series (1984). This patient died due to biventricular dysfunction soon after the surgery at the age of 1 year. He had severe ltAVVR and was noted to have a large cleft requiring patchplasty with autologous pericardium. Late death occurred in 4 patients (6.7% of hospital survivors). One patient had sudden death 3 years after surgery, while the second patient died of cerebral hemorrhage due to acute endocarditis 7 years after surgery. The third patient died of cerebral complication after reoperation for the relief of left ventricular outflow obstruction (LVOTO). The fourth patient, who had been reoperated on for valve replacement for ltAVVR 8 months after the initial surgery, died of viral infection 9 months after reoperation. The actuarial survival rates were 94% and 91% at 5 and 10 years, respectively.

Changes in left AVVR and reoperation
Preoperative examination revealed that 1 patient had severe ltAVVR (grade IV) and 4 patients had grade III ltAVVR, whereas 31 patients had grade II ltAVVR and the other 25 patients had mild to trivial ltAVVR (less than grade I). No patients required valve replacement at the initial operation. There was one hospital death, and postoperative ltAVVR deteriorated in 3 patients, 2 from grade I to grade II and III, and the other from grade II to grade III. In one of the former patients who had grade III left AVVR at hospital discharge, ltAVVR deteriorated so that valve replacement was required 5 months later. In 21 patients ltAVVR decreased (from grade II to grade I in 16 patients, grade III to grade I in 2, grade III to grade II in 2, and grade IV to grade III in 1), although in 37 patients' ltAVVR remained the same at hospital discharge, including grade I in 23 patients and grade II in 14. Consequently, at hospital discharge ltAVVR remained grade II in 18 patients and grade III in 2 patients. During the long-term follow-up, 24 patients were noted to have increased ltAVVR compared to the grade at hospital discharge, including grade III in 8 patients and grade IV in 4. Twelve had ltAVVR that increased from grade I at hospital discharge to II at late follow-up (5 patients from grade I to III, 3 from grade II to III, 3 from grade II to grade IV, and 1 from grade III to IV), whereas only 1 patient's ltAVVR was ameliorated from grade III to II.

Reoperations for ltAVVR were required in 5 patients (8.3% of hospital survivors). Valve replacement with a mechanical valve was performed for 3 patients whose AV valves were dysplastic, whereas valve repair was accomplished in 2 patients in whom dehiscence of the sutured cleft was found. Repairs included reapproximation of redundant leaflets and resuture of the cleft with annuloplasty. Actuarial freedom from reoperation was 91% at both 5 and 10 years. Other patients who have ltAVVR grade III or more are closely followed by regular echocardiogrraphy. Actuarial freedom from postoperative ltAVVR grade III or more was 89% at 5 years and 78% at 10 years, 56% at 15 years (Fig 1).

View larger version (17K): [in this window] [in a new window]   Fig 1. Actuarial freedom from late ltAVVR grade III or more in late follow-up after repair of incomplete atrioventricular septal defect. Patients at risk are shown below. (ltAVVR = left atrioventricular valve regurgitation.)

View larger version (18K): [in this window] [in a new window]   Fig 2. Actuarial freedom from late ltAVVR grade III or more in patients aged less than 2 years old (•) and equal to or greater than 2 years old (). A significant difference (p = 0.0004) is noted between the groups. Patients at risk are shown below. (ltAVVR = left atrioventricular valve regurgitation.)

View larger version (18K): [in this window] [in a new window]   Fig 3. Actuarial freedom from late ltAVVR grade III or more in patients with preoperative ltAVVR more than grade III or more (•) and with ltAVVR less than grade II (). A significant difference (p = 0.0005) is noted between the groups. Patients at risk are shown below. (ltAVVR = left atrioventricular valve regurgitation.)

View larger version (19K): [in this window] [in a new window]   Fig 4. Actuarial freedom from late ltAVVR grade III or more in patients with postoperative ltAVVR grade II or more (•) and with ltAVVR less than grade II (). A significant difference (p = 0.0013) is noted between the groups. Patients at risk are shown below. (ltAVVR = left atrioventricular valve regurgitation.)

View larger version (19K): [in this window] [in a new window]   Fig 5. Actuarial freedom from late ltAVVR grade III or more in patients without cleft repair (•), with partial closure of cleft (), and with complete closure of cleft (). No significant difference is noted among groups. Patients at risk are shown below. (ltAVVR = left atrioventricular valve regurgitation.)

	Comment

Top Abstract Introduction Patients and methods Results Comment References

Despite the excellent short- and long-term mortality rates, left AV regurgitation is the most frequent indication for reoperation after correction of incomplete and complete AVSD, ranging from 3% to 13% reoperation at 5 to 10 years [2, 6–8]. In our series, reoperation was required in 8.3% of hospital survivors and the reoperation free rate at 10 years was 91%. However, significant late ltAVVR was noted in 20% of hospital survivors including those with reoperation, and freedom from late ltAVVR grade III or more at 10 years was 78%. Because patients who have ltAVVR III or more have a potential risk for reoperation in the future, long-term follow-up is mandatory.

Preoperative risk factors affecting late left AVVR
In some series, a higher incidence of preoperative ltAVVR was noted in patients with incomplete AVSD compared with patients with complete AVSD [6, 15–17]. This phenomenon is partially explained by the fact that a higher incidence of additional left AV valve and subvalvular apparatus morphology is observed in patients with incomplete AVSD than in those with complete AVSD [2, 6, 18]. Therefore, abnormalities of the left AV valve and subvalvular apparatus could be risk factors for residual regurgitation, and hence a higher incidence of early and late reoperation after repair of incomplete AVSD. In our series, however, the grade of preoperative ltAVVR was not an independent risk factor for late ltAVVR, but the grade of postoperative ltAVVR was an independent predictor for the deterioration of ltAVVR in late follow-up. Although there may have been fewer patients with abnormalities of the left subvalvular apparatus in our series, our results suggest that more efforts should be focused on left AV repair so as to minimize residual regurgitation, even mild regurgitation. This may also be supported by the interesting findings [16] that the overall increase in valve regurgitation in patients after repair of incomplete AVSD correlated to an increase in mild regurgitation and no change in severe regurgitation, whereas regurgitation usually remained mild in patients after repair of complete AVSD.

Surgical procedures affecting late left AVVR
Although some surgeons prefer to leave the cleft unsutured, it has been found that leaving the clef unsutured leads to significant postoperative ltAVVR [3, 10, 11, 19]. In 2 patients requiring reoperation in this study, the dehiscence of cleft sutures observed could be explained by the extreme tension on the suture line, especially in patents with fragile valvular tissue. Anomalies of the papillary muscles can contribute to this complication in some cases [6]. A more secure technique of cleft closure in small infants and patients with fragile valvular tissue is necessary; cleft sutures reinforced with pericardial pledgets could be useful in such cases [11, 19]. At our institution, since 1996, the cleft has been sutured completely from the annulus to the edge of the leaflet where the marginal chorda is attached. Before 1995, suture of the cleft depended on the surgeon, and there was no intention to close the cleft completely. Consequently, the cleft was closed partially in many patients. However, as illustrated in Figure 5, there was no significant difference in late ltAVVR between patients with partially closed and left open clefts. We believe the complete closure of cleft could reduce late ltAVVR; however, no significant difference was noted between patients with completely closed and partially closed. This may be because of the short follow-up period and the small sample size for patients with complete closure of the cleft. Yet significant residual regurgitation remained in 2 patients with complete closure of cleft and this would suggest that, as reported by others [6, 11, 16, 19, 20] several other factors contribute to the presence of late ltAVVR such as isolated dilatation of the annulus, elongation of the chorda, severe valve deformity, dysplastic AV valve tissue, and a double orifice left AV valve. In this series, most patients who had late ltAVVR grade III or more had no severe valvular deformity, except for 3 patients requiring early reoperation. Therefore, a partially or completely opened cleft or dehiscence of sutures seem to be the major, but not the only, causes of late ltAVVR. We speculate that annuloplasty may further decrease in postoperative ltAVVR, if not stenosed, and it could be more effective when the annulus of the septal attachment of the cleft is plicated, like the usage of a smaller width VSD patch in repair of complete AVSD. Therefore, suturing the cleft together with annuloplasty can certainly improve immediate postoperative residual regurgitation, and may improve valvular function in late follow-up.

In conclusion, both the early results and long-term survival are excellent after repair of incomplete AVSD. However, left AV valve regurgitation is still a significant morbidity in long-term follow-up. The postoperative grade of ltAVVR is an independent risk factor for late ltAVVR, whereas age at operation and the preoperative grade of ltAVVR are not significant risk factors. Although a partially or completely open cleft seems to be a major cause of late ltAVVR, other factors such as annular dilatation at initial operation or during follow-up may also contribute to impairment of late valvular function.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

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This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Toshifumi Murashita Jun-ichi Oba Keishu Yasuda Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Murashita, T. Articles by Yasuda, K. Search for Related Content PubMed PubMed Citation Articles by Murashita, T. Articles by Yasuda, K. Related Collections Congenital - cyanotic