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Divisions of Cardiovascular Thoracic Surgery, and Cardiology, Children’s Memorial Hospital, and the Department of Surgery and Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
Accepted for publication April 23, 2007.
* Address correspondence to Dr Backer, Division of Cardiovascular Thoracic Surgery, Children’s Memorial Hospital, 2300 Children’s Plaza, MC #22, Chicago, IL 60614 (Email: cbacker{at}childrensmemorial.org).
Presented at the Forty-third Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 29–31, 2007.
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Abstract |
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Methods: Between January 2000 and June 2006, 55 infants underwent CAVC repair. Twenty-six patients had a modified single-patch technique; 29 patients had a two-patch technique. Trisomy 21 was present in 23 of 26 and 26 of 29 patients (p = not significant [ns]). Mean age was 4.4 ± 1.3 months (single-patch) versus 5.5 ± 1.9 months (two-patch, p < 0.02). Mean weight was 4.74 ± 0.92 versus 5.28 ± 1.67 kilograms (p = ns).
Results: There was one death in the modified single-patch group (postoperative day 130, liver failure) and no deaths in the two-patch group. Cross-clamp times and cardiopulmonary bypass times were shorter in the modified single-patch group (97.3 ± 19.9 vs 123.3 ± 28.2 minutes, p < 0.0003; 128 ± 25 vs 157 ± 37, p < 0.03). Rastelli classification was type A (18 vs 14), B (1 vs 0), and C (7 vs 15). Mean size of the ventricular septal defect as assessed by transesophageal echocardiogram was 9 ± 2 mm, (single-patch) versus 10 ± 3 mm (two-patch) (p = ns). Median postoperative length of stay did not differ (10 vs 8 days). There was no difference in the degree of postoperative left or right AV valve insufficiency as assessed by serial echocardiography. One patient (4%) required reoperation for mitral insufficiency in the modified single-patch versus three patients in the two-patch group (10%, p = ns). There were no patients with third degree atrioventricular block or that required reoperation for residual VSD in the modified single-patch group. There was one patient with third-degree AV block that required a pacemaker and one patient who had reoperation for a residual ventricular septal defect in the two-patch group (p = ns). No patient in either group required reoperation for left ventricular outflow tract obstruction.
Conclusions: The modified single-patch technique produced results comparable with the two-patch technique in younger patients with similarly sized ventricular septal defects. Furthermore, the modified single-patch technique was performed with significantly shorter cross-clamp and cardiopulmonary bypass times.
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Introduction |
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Material and Methods |
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TopAbstractIntroductionMaterial and MethodsResultsCommentDiscussionReferences |
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Patient Population
Of the 55 infants with complete atrioventricular canal defect that underwent intracardiac repair between January 1, 2000 to June 30, 2006, 26 patients underwent the modified single-patch technique and 29 patients had the two-patch technique. The patients were not randomized; rather, each case was managed according to the individual surgeon’s preference. Figure 2
illustrates graphically the evolution of the modified single-patch technique at Children’s Memorial Hospital. It should be noted at the onset that the majority of the modified single-patch patients were historically in the more recent cohort and this might bias the results. However, during the time period of this study there were no other major changes in operative or cardiopulmonary bypass techniques. The mean age at the time of surgery was significantly lower in the modified single-patch technique group. In these patients the mean age was 4.4 ± 1.3 months, versus 5.5 ± 1.9 months for the patients undergoing the two-patch technique (p = 0.003). The mean weight of the patients undergoing the modified single-patch was slightly less than those having the two-patch technique, 4.74 ± 0.92 kg versus 5.28 ± 1.67 kg. However, this was not statistically significant (p = ns). Trisomy 21 was present in 23 of 26 patients in the modified single-patch group and 26 of 29 patients in the two-patch group (p = ns).
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A medial atriotomy is performed carrying the atrial incision between the inferior vena cava cannula and the right atrium. This provides excellent exposure of the defect. In all patients a vent was placed in the right superior pulmonary vein and this was withdrawn into the left atrium during the valve repair. The first part of the repair involved floating the AV valve leaflets with cold saline. A 6-0 prolene suture was used to identify the projected zone of apposition between the superior and inferior bridging leaflets. Then a series of pledgeted sutures (5-0 Tycron; American Cyanamid, Pearl River, NJ) are placed on the right side of the crest of the ventricular septum (Fig 3). These sutures are passed through the endocardium of the right ventricle and then through the projected point that is the midportion of the common AV valve leaflet. This selection of suture placement divides the common AV valves into right and left AV valves. There is no need to incise the bridging leaflets. The sutures are passed through a previously harvested autologous pericardial patch. These sutures are tied resulting in obliteration of the ventricular component of the defect by pulling the AV valve leaflet "down" to the top of the ventricular septum (Fig 4).
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Results |
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There were three patients in the "classic" two-patch technique group that required reoperation for left AV valve insufficiency. These patients underwent reoperation at three months, five months, and one month postinitial repair. The first patient was initially operated on as a four-month old, 4-kg child with Down syndrome. The superior and inferior bridging leaflets were both incised to identify the crest of the ventricular septum. The child left the operating room with mild to moderate left AV valve insufficiency. Insufficiency progressed and three months later the child required reoperation. Mitral valvuloplasty was performed with successful suture closure of what appeared to be a disrupted zone of apposition.
Another patient in the two-patch technique group has required three reoperations for the left AV valve and pacemaker placement for surgical heart block. This patient was originally operated on at the age of five months weighing 4.4 kg. The patient did not have Down syndrome. There was foreshortening of the papillary muscles of the posterior common leaflet and prolapse of the left inferior bridging leaflet. The patient left the operating room with moderate left AV valve insufficiency that progressed over time. Five months later the patient had a mitral valvuloplasty with pericardial anterior leaflet augmentation and chordal shortening. This repair failed and two weeks later the patient had left AV valve replacement with a #19 St. Jude mitral valve prosthesis (St. Jude Medical Inc, St. Paul, MN). A dual chamber epicardial pacing system was placed ten days later. The child was readmitted three months later with Pannus formation around the periphery of the mitral prosthesis and a clot in the valve. A new #17 high profile St. Jude mitral valve prosthesis (St. Jude Medical Inc) was placed. The child was readmitted one month later, again with clot formation on therapeutic Coumadin (DuPont, Wilmington, DE). She responded to tissue plasminogen activator (tPA). She was readmitted two months later, again with a nonfunctional leaflet secondary to clot formation and underwent successful tPA therapy. The child has had no admissions since that time and is currently well.
A third patient requiring reoperation on the left AV valve was a 32-week premature infant with a birth weight of 1.6 kg. The initial AV canal repair was performed at four months of age when the child weighed 4.3 kg. The child was unable to be weaned from the ventilator and was returned to the operating room one month later. A dehiscence of the anterior mitral valve zone of apposition was repaired and a residual ventricular septal defect was closed.
The degree of postoperative left AV valve insufficiency was assessed by serial echocardiography. Left AV valve insufficiency was assessed as trivial, mild, mild to moderate, moderate, moderate to severe, or severe depending on the width of the color jet and the extent of the jet into the left atrium. The degree of left AV valve insufficiency for the modified single-patch versus the two-patch technique is illustrated in Figure 8A. The mean follow-up in the modified single-patch group is 1.8 years and in the two-patch group is 3.1 years. There was no statistical difference in the degree of left AV valve insufficiency, the majority having less than moderate insufficiency (one-patch, 23 of 26; two-patch, 21 of 29). It is important to note that of the four patients that had a reoperation on the left AV valve, in all cases this was required between one and five months after the initial repair, well within the 1.8 and 3.1 year mean follow-up of the two groups.
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One patient in the two-patch technique group required a pacemaker at nine days postoperatively for complete heart block. No patient in the single-patch group required a pacemaker.
The degree of LVOT stenosis was assessed by serial echocardiography. Only three patients had a measurable gradient. Two modified single-patch patients had respective gradients of 14 and 18 mm Hg, and one two-patch patient had a gradient of 22 mm Hg. There were no reoperations for LVOT obstruction in either group. However, it should be noted that the mean follow-up is relatively short at 2.5 years.
The results of the intracardiac anatomy (Rastelli classification) and ventricular septal defect size are shown in Table 2. There was no statistical difference in VSD size or Rastelli classification comparing the two groups. One patient in the two-patch group required a reoperation for a residual VSD (patient no. 2 above with reoperation also for left AV valve insufficiency); no patient in the modified single-patch group required reoperation for a residual ventricular septal defect.
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Comment |
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There are many centers that currently use the two-patch technique using a Gore-Tex or Dacron patch for the ventricular component and a pericardial patch for the atrial component [9–11]. There are also groups that still use the "classic" single-patch technique, which involves using a portion of the pericardial patch for the ventricular component, cutting the AV valve, and resuspending the AV valve to the middle of this pericardial patch [12–16]. The top portion of the pericardial patch is then used to close the atrial septal defect. Our previous analysis comparing the results of the two-patch technique at Children’s Memorial Hospital with the "classic" single pericardial patch technique at other centers revealed minimal differences in outcomes between the two groups [17]. Advocates of these older techniques as compared with the modified single-patch technique point to the potential for LVOT obstruction caused by "pulling" the AV valve down to the crest of the VSD and crowding the LVOT. They also voice concern for potential residual VSD (no VSD patch) and potential increase in left AV valve insufficiency based on pulling the AV valve down to the crest of the septum and having the hinge-point at a nonphysiologic height.
Our enthusiasm for the modified single-patch technique started with the evidence provided by Wilcox and colleagues [3] in 12 patients of shorter cardiopulmonary bypass and aortic cross-clamp times. This enthusiasm was encouraged by the excellent results reported in a larger group of 47 patients reported by Nicholson and colleagues [4]. This series was updated in a presentation by Nunn [18] at the American Association for Thoracic Surgery 86th annual meeting in 2006. The outcomes now reported by Nunn truly appear to be superior to that of the classic two-patch technique with a 1.6% mortality rate in 128 patients, no reoperations for residual ventricular septal defects, no reoperations for LVOT obstruction, and no conduction abnormalities. In addition, the incidence of mitral valve reoperation was very low at 2.3%. Jonas [19] has also reported excellent results with the modified single-patch (Australian Technique). He reported 34 patients operated on between 1997 and 2002. There were no deaths and no reoperations for LVOT obstruction or left AV valve insufficiency.
The focus on repairing complete atrioventricular canal defects earlier and earlier in infancy is certainly facilitated by the modified single-patch technique. The removal of the VSD patch from the operation considerably reduces the degree of difficulty of this procedure. It also removes a potential source of error. The issues brought up by surgeons who are uncomfortable with the modified single-patch technique include residual VSD, LVOT obstruction, and left AV valve insufficiency. Their concerns are well-addressed by our results. No patient in the modified single-patch group had a significant residual VSD requiring reoperation, similar to the findings of Nunn [18] and Jonas [19]. No patient in our series had a LVOT obstruction requiring reoperation, again similar findings to the series reported by Nunn and Jonas. The limitation here is our short length of follow-up. In our series there was no difference in the degree of right or left postoperative AV valve insufficiency. Only one patient in the modified single-patch group required a reoperation on the left AV valve compared with three in the two-patch group. This is despite the theoretic advantage of the two-patch and classic one-patch techniques anchoring the AV valves at the same height that they are at prior to the repair. This may be partially explained by the fact that the AV valves do not need to be divided with the modified single-patch technique. Incising the common AV valves as part of the repair has been shown to increase the need for reoperation on the left AV valve [20]. One of the patients in our two-patch group that required left AV valve reoperation had the valve incised as part of the first operation. Another possible explanation for the success of the modified single-patch technique is that the degree of difficulty of the repair is less with the modified single-patch technique as it avoids potential for error in creating the VSD patch. This patch in theory can be too large or too long, distorting the AV valve repair. In Nunn’s series of 128 patients there were only three reoperations for mitral valve repair or replacement; interestingly, all in non-Down children. This truly addresses the concern noted by Crawford and Stroud in their review [16] that the incidence of late reoperation for left AV valve insufficiency has not improved over time using the standard single-patch technique.
One word of caution regarding the patient with a very large VSD or the patient with tetralogy of Fallot and atrioventricular canal: in a recent patient with a large VSD (12 mm) I attempted to use the modified single-patch technique. However, when the AV valves were floated and positioned at the crest of the septum it was apparent that the left lateral leaflet and a portion of the inferior bridging leaflet were prolapsing at a height that did not allow them to coapt with the superior bridging leaflet. Because of this we elected not to use the single-patch technique, but rather the standard two-patch technique with a rather large Gore-Tex patch to close the ventricular septal defect. Although in our statistical analysis there was no difference in VSD sizes there is a slight trend that in the patients that have the modified single-patch technique the VSDs were slightly smaller, and also there were slightly fewer patients with the Rastelli type C classification which tend to have larger ventricular septal defects. For the ventricular septal defect that is 10 mm or less in size based on the results of this series we would not hesitate to use the modified single-patch technique. As the VSD progresses from 10 to 15 mm in size; however, some of these patients with the very large VSDs may indeed benefit from a two-patch technique. In the patients with tetralogy of Fallot and AV canal (although they are not discussed in this series), for one recent patient we used Gore-Tex beneath the superior bridging leaflet and closed the inferior bridging leaflet directly to the crest of the septum using the modified single-patch technique. Hence, a Gore-Tex patch was used under the superior bridging leaflet because of the large size of the ventricular septal defect. LaCour-Gayet and colleagues [21] have described this technique in detail.
In conclusion, the results of the modified single-patch technique were at least as good as our previous standard repair using the two-patch technique. Moreover, these patients were repaired with shorter cross-clamp times and shorter cardiopulmonary bypass times, and the patients were younger. Although this series was not randomized, the patients had similarly sized VSDs. At this time the modified single-patch technique is our preferred approach for the majority of infants with complete atrioventricular canal septal defect.
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Discussion |
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DR BACKER: We evaluated the VSD size in a transesophageal apical four-chamber view measuring from the crest of the ventricular septum to the level of the AV valve in end-diastole. As this diagram illustrates, this was the VSD size. We went back and looked at the echo tapes on all the patients and the repair type was blinded to the echocardiographers.
DR JOSEPH J. AMATO (Chicago, IL): I congratulate you on your results, Carl. Prior to leaving the operating room in 2003, I really wanted to wait for long-term results of this relatively new Nuss technique. I worried about impingement on the left ventricular outflow tract with this technique and would have planned to cheat on the use of the septal portion of the common anterior leaflet. The question I am asking is: "Do you subconsciously sort of take more tissue from the tricuspid side and push it over to the left side and describe that in your technique, because I believe that’s very important for the younger surgeons to understand that this might be very appropriate. If I were to perform this modified approach to atrioventricular septal defects, I would steal from the right side to modify the left to avoid narrowing of the aortic valve orifice thus about the blocking of the aortic valve or the left ventricular stenosis. And, also, does Nunn or anybody else have a longer series of five years or more showing that there might be some compromise of the aortic orifice? Thank you.
DR BACKER: That’s a very good point, Joe. If my memory serves me correctly, Dwight McGoon was the one who said, "steal from the tricuspid and give to the mitral." When I put that suture through the bridging leaflet, I try to give as much to the mitral valve as possible knowing that the left AV valve is really the key to this operation. I’m sure that we subconsciously do that, and it’s actually a good thing to do. Regarding your second question about a longer series of patients; Graham Nunn presented his series at the AATS (American Association for Thoracic Surgery) last spring, and now he has 128 patients undergoing the modified single-patch technique with no reoperations for left ventricular outflow tract obstruction. He has no patients with a pacemaker, and three patients out of 128 with left AV valve reoperation, all of whom were non-Down patients. His mean follow-up was seven years.
DR HENRY L. WALTERS (Detroit, MI): Carl, as you have shown with your data, you are seeing a trend toward fewer AV valve problems on long-term follow-up when you use the single-patch technique that you describe in this paper. Now that you have used this single-patch technique for a while do you have a sense as to why you are possibly seeing fewer long-term AV valve problems?
DR BACKER: I would speculate for a couple of reasons. One is that the placement of the Gore-Tex VSD patch needs to be just right. If you make the patch too long or make it too "high," you can disrupt the mechanism of the coaptation of the left AV valve. In contrast, Graham Nunn calls the modified single-patch the "simplified" single-patch. It is clearly easier and simpler, and by taking out that degree of complexity of the two-patch operation you make AV valve repair that much "simpler." It’s amazing how in the first couple of the original operations that we performed the echocardiographers were really surprised that there was only trivial or no AV valve insufficiency, whereas almost all of our two-patch technique patients would have at least mild insufficiency.
DR JAMES S. TWEDDELL (Milwaukee, WI): That was a very nice presentation. The one patch technique would, at first, appear to place the patients at increased risk for development of left ventricular outflow tract obstruction, especially in the face of a large ventricular septal defect because the anterior leaflet would be secured to the scooped-out septum thereby exaggerating the elongated left ventricular outflow tract thought to contribute to the development of left ventricular outflow tract obstruction. If there was an anterior to posterior plication, that is, if the stitches that you place along the septum, the horizontal mattress stitches, resulted in a decrease of the anterior-posterior dimension of the atrioventricular valve then this could potentially achieve some redundancy of the anterior leaflet. Adding this redundancy to the anterior leaflet would permit upperward movement of the anterior leaflet between the annulus and the coaptation edge during systole and move this tissue out of the ventricular outflow tract obstruction thereby minimizing the potential for development of left ventricular outflow tract obstruction. I was wondering if you think that in performing this repair a degree of anterior-posterior annular plication takes place? Thanks.
DR BACKER: That’s a good point, Jim. In Graham Nunn’s series he makes a point of actually plicating what becomes the anterior common leaflet using a little strip of Dacron to perform an annuloplasty. We originally did not specifically make a point to do that and took essentially equal bites on the valve and the pericardium. However, after Nunn’s presentation last April, I’ve started plicating the anterior leaflet and bringing it together but not specifically with a Dacron strip. Graham Nunn has no left ventricular outflow tract obstruction in over 100 patients using that technique, so I think that the numbers are starting to speak for themselves.
DR JOHN E. MAYER (Boston, MA): Just a few technical questions, and maybe the illustrations don’t reflect what you actually do. For me, it seems that the most critical thing is getting the cleft area lined up right. And so I actually, no matter what technique that I use, that’s sort of my first step. You didn’t show that that way in your drawing, but what role does that play?
DR BACKER: Yes, that actually should be in the drawing. In the legend of the manuscript I talk about that. The first thing I do is float the AV valve.
DR MAYER: Right.
DR BACKER: Then I put a 7-0 Prolene suture to mark what I think is going to be the top of the zone of apposition. Then I often refloat the valve, and then I sometimes replace that suture. Sometimes it takes—I’m exaggerating—but I’ll sometimes spend almost a whole cross-clamp determining where that’s going to be. Once everything is lined up, it just all falls into place. But that is a very important point. Floating the AV valve to see where everything looks like it’s going to fit best and then marking it with a suture is extremely important.
DR MAYER: The second question is, what you do in patients who have a more anterior extension of the VSD, so this tetralogy-AV canal type patient, and do you still use this technique or are you still putting patches in there?
DR BACKER: We don’t have very many TOF (tetralogy of Fallot)/AV canals, but the last one in which I used a patch for underneath the superior bridging leaflet, but the inferior bridging leaflet was --
DR MAYER: Already fused?
DR BACKER: -- brought down to the VSD. There was a small VSD component there and we used the simplified single-patch technique for that part of the repair. So the patch was only underneath the superior bridging leaflet.
DR MAYER: And the last question is, do you do anything with the pericardium or is it fresh?
DR BACKER: No. The pericardium is autologous pericardium, not treated.
DR MAYER: Not treated. The one thing that I would say, for whatever it’s worth, is that I think that sort of shortening the distance from the most anterior or superior part of the canal to back by the AV node and the coronary sinus is actually, I’ve found, pretty important in trying to minimize the AV valve regurgitation. And essentially it’s almost like an annuloplasty, if you will. And actually, depending on what technique you use, you can accomplish that a whole variety of different ways. But my own sense is that’s actually a pretty important aspect of this, and I was interested to hear your comment that you’re sort of moving in that direction.
DR BACKER: Right. The paper that Graham Nunn presented last spring was really impressive, and this is the technique he’s been using. Once we saw what he was doing, we gravitated towards this technique also.
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C. L. Backer Invited Commentary Ann. Thorac. Surg., January 1, 2009; 87(1): 203 - 203. [Full Text] [PDF]
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] and two-patch [
]). (CAVC = complete atrioventricular canal.)
= mean age all repairs; 
= mean age 1-patch; 
= mean age 2-patch.)