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Retrospective analysis of stage I Norwood procedures with tricuspid valve insufficiency in the past 5 years
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     Shizuoka Children's Hospital, 860 Urushiyama, Aoi-ku, Shizuoka City, Shizuoka, 420-8660 Japan

    Presented at the joint 20th Annual Meeting of the European Association for Cardio-thoracic Surgery and the 14th Annual Meeting of the European Society of Thoracic Surgeons, Stockholm, Sweden, September 10–13, 2006

    Abstract

    Moderate/severe tricuspid valve regurgitation is one of the important risk factors affecting outcome after the Norwood procedure. We now evaluate tricuspid valves more precisely echocardiographically and manage tricuspid valve regurgitation even when performing the stage I Norwood procedure. We reviewed all patients (tricuspid valve regurgitation moderate/severe group=10, mild/trivial non-regurgitation group=19) who underwent the stage I Norwood procedure with a ventricle to pulmonary artery conduit in our institution between January 2001 and March 2006. Four of 10 patients with tricuspid valve regurgitation underwent tricuspid valvuloplasty in the stage I procedure. We controlled pulmonary flow in all patients with tricuspid valve regurgitation by clipping the conduit. Tricuspid valve regurgitation improved significantly after the stage I Norwood procedure in all patients (P<0.01). Operative mortality was similar in the two groups. There were no significant differences of the actuarial overall survival rate in both groups (P=0.38, log-rank test). Follow-up is complete in all patients. The rate of final repair completion was similar in the two groups (regurgitation, 5/10; non-regurgitation, 10/19). Appropriate pulmonary flow control and surgical repair in the Norwood procedure improved the outcome in terms of postoperative survival in patients with hypoplastic left heart syndrome who had moderate/severe tricuspid valve regurgitation.

    Key Words: Hypoplastic left heart syndrome; Tricuspid valve regurgitation; Tricuspid valvuloplasty

    1. Introduction

    The outcome of patients who undergo the Norwood procedure has improved markedly in recent years. TR is of particular interest because it is one potential area in which surgical intervention may be indicated due to an intrinsic abnormality of valve anatomy or due to any of the factors, such as RV dysfunction or dilation. In addition, the tricuspid valve is subjected to systemic pressure rather than pulmonary workloads. Because of the multifactorial causes of TR, simple repair of the valve may not address the underlying problem and hence, fail to improve TR or patient outcome. To address this issue, we performed a retrospective review of all patients with HLHS who had TR to assess early and late outcomes, as well as procedural and anatomic variables predictive of successful control of TR.

    2. Patients and methods

    2.1. Study design

    We performed echocardiography at a few days before Norwood procedure and one month later after Norwood procedure. TR was graded on a scale of 0 to 4+. The grading scale was defined as follows: 0, none; 1+, trivial; 2+, mild; 3+, moderate; and 4+, severe. The TR group was defined as patients who had TR with scores of 3+ to 4+ before the Norwood procedure and the non-TR group as those with scores of 0 to 2+.

    2.2. Patients

    January 2001 through March 2006, 29 patients underwent Norwood procedures at Shizuoka Children's Hospital, Shizuoka, Japan. In the TR group, 10 of 29 patients had scores of 3 to 4+ before surgery, and in the non-TR group, 19 had scores of 0 to 2+. Median age at Norwood procedure in the non-TR and TR group was four days and three days and median body weight was 2.8 kg and 3.0 kg, respectively. There were thus no significant differences between the two groups. In general, valve repair was undertaken when TR scores were 4+ and tricuspid valves were not dysplastic. The HLHS group was defined as patients who had hypoplasia or atresia of the aortic valve and underwent the Norwood procedure.

    2.3. Surgical technique

    The Norwood procedures were performed using a right ventricle to pulmonary artery (RV-PA) conduit [1]. If the echocardiogram showed TR before the Norwood procedure, we examined the tricuspid valve at the time of the enlargement of the atrial septal defect. Standard methods of cardiopulmonary bypass were used, with initial examination of the tricuspid valve performed by filling the right ventricle with saline. Intraoperative determination was made of the location of regurgitation, the diameter of the annulus, leaflet prolapse, and leaflet cleft. The preoperative echocardiogram was used to determine the methods of repair. Partial annuloplasty like Kay suture [2] was commonly performed in patients with leaflet cleft or annular dilatation with failure of leaflet coaptation and generalized central regurgitation. A variety of techniques were used in performing tricuspid valvuloplasty (TVP), depending on the specific cause of regurgitation in each patient. Reduction annuloplasty and repair of cleft leaflets were both performed, often in combination.

    We performed modified ultrafiltration (MUF) in all cases. After MUF, we controlled the pulmonary blood flow by clipping the RV-PA conduit. Generally, we aim for systemic oxygen saturation of approximately 80% on FiO2 1.0.

    3. Results

    3.1. Patients

    In the TR group, 4 of 10 patients had a TR score of 4+ before the first-stage palliation and the other six had scores of 3+. In the non-TR group, 3 of 20 patients had TR scores of 2+ and the other 17 had scores of 0 or 1+. Four of 10 patients in the TR group underwent TVP even if the staged Norwood procedure was performed. If the SpO2 was over 85% on FiO2 1.0, patients underwent pulmonary blood flow control by clipping the RV-PA conduit during this operation. We controlled pulmonary blood flow by clipping RV-PA conduit and finally, SpO2 was around 80% on FiO2=1.0.

    Operative survival was 100% in the TR group and 95% (19/20) in the non-TR group. The rate of the reach to the 2nd operation was 60% (6/10) in the TR group and 78.9% (15/19) in the non-TR group. And moreover, the rate of final surgical repair completion (Fontan procedure, 12; biventricular repair, 3) was similar at 5 of 10 patients (50%) in the TR group and 10 of 19 (52.6%) in the non-TR group. The actuarial survival rate was 81.6% vs. 64.8% at five years in the non-TR vs. TR group (P=0.38, log-rank test).

    In all TR patients, TR improved significantly after the stage I Norwood procedure (P<0.01) (Fig. 1). In the TR group, 8 of 10 patients had an abnormality of the tricuspid valve (cleft in four, chordae shortening in three, and abnormal chordae attachment in one). Only one patient had a tricuspid valve abnormality (chordae shortening) in the non-TR group (Table 1).

    4. Discussion

    Despite marked improvements in the survival rates of HLHS patients over the past decade, interstage mortality rates remain significant [3–7]. An important factor in this ongoing attrition is the development of significant TR, which has been reported to occur in from 8.5% to 16% of patients with HLHS [8–10]. Our data suggest that moderate to severe TR is a relatively common finding in patients with HLHS, with a frequency of approximately 34.4%. Overall, the percentages of patients progressing to successful final repair completion and the overall survival rates after the Norwood procedure are excellent in this very high-risk subpopulation of patients with HLHS and TR and are the same as in patients without TR. Our data suggest that moderate to severe TR is a relatively common finding in patients with HLHS who have morphologic abnormality of the tricuspid valve, with a frequency of approximately 80%. Patients with HLHS who have morphologic abnormalities of the tricuspid valve require additional attention.

    We therefore recommend that patients with HLHS be considered for TVP and the control of pulmonary flow during the Norwood procedure when there is clinical and/or echocardiographic evidence of moderate to severe TR, regardless of valve morphology.

    Conference discussion

    Dr B. Maruszewski (Warsaw, Poland): What is the percentage of patients that you do the Norwoods on If you have this problem, how frequently does the problem of tricuspid regurg exist in your Norwood population

    Dr Ota: In our series, we had 23% patients with hypoplastic left heart syndrome who had tricuspid valve regurgitation.

    Dr Maruszewski: Did you follow these patients after this procedure

    Dr Ota: Yes.

    Dr Maruszewski: And what was your follow-up and what were the outcomes in next months after these procedures

    Dr Ota: In the tricuspid regurgitation group, 100 operative survival.

    Dr Maruszewski: But did you follow the further performance of the function of the tricuspid valve after this procedure How long is your follow-up

    Dr Ota: So if the baby had bad cardiac function, the ventricle was dilated and finally, the tricuspid regurgitation was increased. It's a kind of a vicious cycle.

    Dr Maruszewski: Have you applied this technique to other situations, the early post-Norwood patient Have you applied this tricuspid valvoplasty technique to other patients

    Dr Ota: Yes. We applied this technique to Asplenia patients.

    Dr C. Schreiber (Munich, Germany): Personally, I would not touch a moderately insufficient AV valve. I would only address severe forms. But now a question. Which size of shunt were you using and were you eventually taking the clip off or how was your approach

    Dr Ota: We use a 5-mm RV-PA shunt for these 3-kg babies.

    Dr Schreiber: Only 5

    Dr Ota: 5.

    Dr Schreiber: And did you eventually take the clip off after a few days or not in any patient Did you leave the clip on all the time

    Dr Ota: Yes. Some clips are taken off when we perform the chest closure.

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