Ann Thorac Surg 2002;73:58-62
© 2002 The Society of Thoracic Surgeons
Original article: cardiovascular
Surgical repair of supposedly multiple defects within the apical part of the muscular ventricular septum
Victor T. Tsang, FRCS*a,b,
Tain-Yen Hsia, MDa,b,
Robert W.M. Yates, MRCPa,b,
Robert H. Anderson, FRCPatha,b
a Cardiothoracic Unit, Great Ormond Street Hospital For Children NHS Trust, London, England, UK
b Institute of Child Health, University College London, London, England, UK
Accepted for publication July 30, 2001.
* Address reprint requests to Dr Tsang, Cardiothoracic Unit, Great Ormond Street Hospital For Children NHS Trust, Great Ormond St, London, England WC1N 3JH, United Kingdom
e-mail: tsangv{at}gosh.nhs.uk
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Abstract
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Background. A distinct defect has been described within the apical part of the muscular ventricular septum, which has multiple orifices when seen from its right ventricular aspect. Closure has been suggested using umbrella devices introduced on a catheter. Such an intervention, however, can be technically difficult in small infants.
Methods. We have recently seen two examples of this type of complex communication between the apexes of both left and right ventricles. Neither could be closed by catheterization. A surgical approach was used through a modified apical right ventriculotomy. We have also studied two autopsied specimens, which clarify the morphologic arrangement.
Results. Both patients were closed successfully, with trivial residual shunt and good biventricular functions. The patients were clinically well at 2-year follow-up.
Conclusions. Surgical division of right ventricular trabeculations makes it feasible to identify and repair the septal deficiency, which is a solitary hole. On the basis of our morphologic study, we offer an explanation for the anatomic arrangement that differs from the one proposed by recent previous investigators. If the ventricular incision is appropriately placed, our anatomic studies suggest that it is possible to visualize the solitary opening from its right ventricular aspect, and achieve surgical closure with a single patch.
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Introduction
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Emphasis has been given recently to a distinct variant of a defect within the apical part of the muscular ventricular septum, which presents with multiple orifices as seen from its right ventricular aspect. One group of investigators has advocated closure using transcatheter placement of an umbrella device [1]. Such an intervention, however, can be technically difficult in small infants. Another group, therefore, has recommended a surgical approach [2]. We have also seen recently two examples of this type of defect. Neither could be closed interventionally. A surgical approach using a modified apical right ventriculotomy, in contrast, proved successful. On the basis of our surgical experience, combined with study of autopsied hearts, we offer an explanation for the morphologic arrangement that is different from the one proposed by the previous investigators [1, 2].
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Material and methods
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Patients
During a period of 2 months in 1998, two unrelated female infants born at term, but seen at the ages of 8 and 10 months, and weighing 3.3 and 3.5 kg, respectively, presented to our cardiothoracic surgical service with an echocardiographic diagnosis of multiple defects within the apical part of the muscular ventricular septum. Both had become significantly symptomatic shortly after birth, with dyspnea, hypoxia, and failure to thrive despite aggressive medical treatment. One of the patients also had an additional significant perimembranous defect, and had undergone banding of the pulmonary trunk at the age of 1 month, having been born with a weight of 2 kg.
Preoperative evaluation was undertaken using cross-sectional echocardiography and color Doppler flow mapping. The defects were best seen using subcostal, apical, and parasternal short-axis views. In both patients, large defects were seen in the apical part of the muscular septum, with multiple lines of entry into the right ventricular apex, associated with hypertrophy of the coarse apical trabeculations (Fig 1).
The flow through the defects in both patients was from left-to-right to the ventricular apex, and then superiorly toward the right ventricular infundibulum. Thus, in both patients, there was a single large opening through the apical part of the muscular septum, but with the solitary stream broken into multiple pathways by the coarse trabeculations adherent to the right ventricular aspect of the muscular septum. The multiple openings into the right ventricle were close to the ventricular apex, and distant from the smooth-walled outlet, or infundibular, component, which supported the leaflets of the pulmonary valve.
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Fig 1. Echocardiogram (apical four-chamber view) demonstrating an apical defect in the muscular septum (VSD) that opens adjacent to prominent trabeculations in the right ventricle.
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At operation, a small ventriculotomy of approximately 2 cm was made at the apex of the right ventricle, the incision running parallel to the anticipated site of the muscular ventricular septum, and as close as possible to the anterior interventricular artery without endangering that artery. This incision takes the surgeon between the anterior papillary muscle of the tricuspid valve and the septum, and should not place the papillary muscle at risk. The coarse trabeculations found within the right ventricular apex were divided to facilitate visualization of the margins of the defect, which proved to be a solitary hole within the apical part of the muscular ventricular septum. Once adequate exposure was obtained, an oversized Gore-Tex patch (W. L. Gore & Associates, Flagstaff, AZ) was fashioned and placed through the defect, being secured on the left ventricular side of the superior, inferior, and posterior margins of the defect by horizontal mattress sutures anchored with autologous pericardial pledgets. After the sutures were tied down, the right ventriculotomy was closed with a double layer of continuous 5-0 Prolene (Johnson & Johnson International, Beerse, Belgium) buttressed with autologous pericardium, this layer of stitches also sandwiching the anterior margin of the patch (Fig 2).
Both patients made an uneventful recovery. Echocardiograms before discharge demonstrated a minimal residual defect with negligible flow from left-to-right in both patients, with good biventricular function, and low right ventricular pressure. At follow-up 2 years later, both patients remained clinically well. The right ventricular function was satisfactory and there was no evidence of any significant tricuspid valve regurgitation.
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Fig 2. Schematic representation of the technique used, anchoring the patch on the left ventricular (LV) surface posteriorly, and within the right ventricular (RV) surface anteriorly. (SP = septum.) The arrangement is shown in short axis (A) and four-chamber projection (B).
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Anatomic considerations
The ventricles are the pumping chambers of the circulation. Like all pumps, the ventricles are furnished with valves, one for the ventricular inlet, and the other for the ventricular outlet. These valves open to, and take origin from, the apical trabecular component of the ventricles, which provides the force of the pump. When analyzed in this fashion, each ventricle is readily described in tripartite fashion. It is much harder, in contrast, to define the ventricular septum in terms of three parts. Indeed, in the normal heart, it is possible with precision only to distinguish between the fibrous membranous and the muscular parts of the ventricular septum. The two sides of the muscular septum, nonetheless, on their apical aspects, have characteristic trabeculations on their opposite surfaces that provide the most obvious anatomic features of rightness and leftness. These trabeculations are fine and criss-crossing in the morphologically left ventricle, and coarse in the morphologically right ventricle. In the hearts examined surgically, the holes were found toward this apex of this muscular septum. It is known that such holes within the muscular septum can be positioned so as to open between the ventricular inlets, between the outlets, or between the two apical components [3]. We have encountered two hearts at autopsy that are directly comparable to those seen at operation. A solitary opening was found within the apical part of the muscular septum (Fig 3A),
but the adherence of apical trabeculations to the right ventricular aspect of the septum meant that the solitary defect had multiple right ventricular orifices (Fig 3B). Analysis of our second heart, coupled with the information gained from our clinical experience, made it possible for us to reveal the anatomic arrangement by making two incisions at the apex of the right ventricle for demonstration (Fig 4a).
When viewed through the incision closest to the interventricular septum, the ventricular septal defect was seen to have solitary openings on both its right (Fig 4b) and left (Fig 4c) sides. This incision entered the right ventricle between the anterior papillary muscle and the septum. When viewed through the more lateral incision, however, the solitary opening to the right ventricle was crossed by apical trabeculations, giving the spurious impression of multiple defects opening to the apex of the morphologically right ventricle (Fig 4d).
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Fig 3. This picture of a heart with a ventricular septal defect shows a solitary opening without the apical muscular septum when viewed from the left ventricular aspect (A).Opening the right ventricle (B and C) shows how septoparietal trabeculations adherent to the septal surface give the impression of multiple defects in the septum (asterisks) as seen from the right ventricular aspect.
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Fig 4. This heart also has a solitary defect toward the apex of the muscular septum. We opened the right ventricle through two incisions for demonstration (a). The large dots indicate the site of the muscular septum, delineated by the anterior interventricular artery. When opened through incision 2, closest to the septum, a solitary opening (white star) is seen on both the right (b) and left (c) ventricular aspects of the septum. The black asterisks in b show the divided apical trabeculations. When the defect is viewed through incision 1, placed more laterally (d), however, then multiple openings are seen at the apex of the right ventricle (white stars).
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Comment
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The optimal surgical technique for repair of defects within the muscular ventricular septum close to the ventricular apexes, particularly when multiple, has still to be determined [1, 2, 4, 5]. All surgeons acknowledge, nonetheless, that these defects are difficult to close, particularly when encountered in small infants presenting with heart failure. It was pointed out as long ago as 1977 [6] that exposure and repair of these defects was much easier when approaching through the left ventricle, as this permitted appraisal of the solitary left ventricular opening, rather than the multiple orifices seen from the right ventricular aspect. Although this approach facilitated the repair, debate has continued regarding the potential sequels. Some have cited clinical observations of late myocardial dysfunction, formation of apical aneurysms, and even arrhythmogenesis [4–7]. If the defects are situated very close to the anterior cardiac surface, there is the danger that the necessary left ventricular incision may damage the coronary arteries, and thus increase the risk of myocardial dysfunction.
The less dangerous surgical approaches from the right side, in contrast, have been plagued by poor visualization, and the uncertainties of identifying the true margins of the defect when approaching through the coarse trabeculations found within the right ventricular apex. It was in part to avoid such difficulties that Kumar and colleagues proposed their solution using interventional catheterization [1]. Although we were aware of the advantages of such an interventional approach, we considered the technique to be unduly difficult in small infants. Our surgical approach, by dividing and separating the coarse apical right ventricular trabeculations, permitted us to recognize precisely the margins of the defect, and thus gain the advantages of the left ventricular approach without the need to incise the left ventricle. In addition, we were able to place the majority of our stitches through the left side of the septum, ensuring the security of closure by sandwiching the anterior margin of the patch within the right ventriculotomy. Stellin and colleagues [2] have similarly advocated the advantages of the right ventricular approach for these patients.
Although supporting their contention in terms of surgical access [2], we offer an alternative explanation to account for the morphology of the defects. Both Stellin and associates [2] and Kumar and colleagues [1] argue that the defects extend from the apex of the left ventricle to the infundibulum of the right ventricle. This depends on the definition of an infundibulum. In choosing the definitions used in this study, we have been guided by the so-called morphologic method, developed by Van Praagh and colleagues [8]. In essence, this states that anatomic structures should be defined on the basis of their own intrinsic morphology. Thus, the infundibulum is the outlet component of the right ventricle, and as such is removed by the surgeon when performing the Ross procedure [9]. The apical part of the right ventricle is characterized by its uniformly coarse apical trabeculations. It is separated from the apical part of the left ventricle by the muscular ventricular septum, known to carry on its crest the ventricular conduction tissues [10]. In the normal heart, it is not possible to find any discrete muscular outlet septum, as the subpulmonary infundibulum is a complete sleeve of free-standing musculature [9]. Evidence is now emerging that, as the outflow tracts develop, and as the aorta is incorporated into the left ventricle, it is the outflow cushions that septate the outlets, which become muscularized to form this free-standing sleeve of muscular infundibulum [10]. Only when malaligned relative to the primary muscular septum do the outlet cushions become muscularized to form an identifiable muscular outlet septum, and that septum never carries the ventricular conduction tissues.
Thus, as based on this interpretation of ventricular structure, it is possible to explain how incomplete compaction of the apical muscular septum leaves a large hole within its apical part. The adherence of the coarse apical trabeculations within the right ventricle to the septal surface, however, serves to provide this solitary defect in the septum with multiple right ventricular orifices. Surgical division of the right ventricular trabeculations, as we have shown, makes it feasible to identify and repair the solitary septal deficiency.
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Acknowledgments
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Tain-Yen Hsia is the 1999 National Science Foundation International Postdoctoral Research Fellow (INT-9802808). Robert H Anderson is supported by the British Heart Foundation together with the Joseph Levy Foundation. Research at the Institute of Child Health and Great Ormond Street Hospital For Children NHS Trust benefits From Research and Development funding received From the NHS Executive. We express our thanks to all our other clinical colleagues involved in the care of the patients described in our study.
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References
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Kumar K., Lock J.E., Geva T. Apical muscular ventricular septal defects between the left ventricle and the right ventricular infundibulum: diagnostic and interventional considerations. Circulation 1997;95:1207-1213.[Abstract/Free Full Text]
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Stellin G., Padalino M., Milanesi O., et al. Surgical closure of apical ventricular septal defects through a right ventricular apical infundibulotomy. Ann Thorac Surg 2000;69:597-601.[Abstract/Free Full Text]
-
Wolleneck G., Wyse R., Sullivan I., Elliott M., de Leval M., Stark J. Closure of muscular ventricular septal defects through a left ventriculotomy. Eur J Cardio-thorac Surg 1996;10:595-598.[Abstract]
-
Kitagawa T., Durham L.A., Mosca R.S., Bove E.L. Techniques and results in the management of multiple ventricular septal defects. J Thorac Cardiovasc Surg 1998;115:848-856.[Abstract/Free Full Text]
-
Serraf A., Lacour-Gayet F., Bruniaux J., et al. Surgical management of isolated multiple ventricular septal defects. Logical approach in 130 cases. J Thorac Cardiovasc Surg 1992;103:437-442.[Abstract]
-
Hanna B., Bridges N.D., Mayer J.D., Castaneda A.R. Clinical and myocardial status after left ventriculotomy for ventricular septal defects. J Am Coll Cardiol 1991;17(Suppl):110A.
-
Merrick A.F., Yacoub M.H., Ho S.Y., Anderson R.H. Anatomy of the muscular subpulmonary infundibulum with regard to the Ross procedure. Ann Thorac Surg 2000;69:556-561.[Abstract/Free Full Text]
-
Van Praagh R., David I., Wright G.B., Van Praagh S. Large RV plus small LV is not single RV. Circulation 1980;61:1057-1059.[Medline]
-
Lamers W.H., Virágh S., Wessels A., Moorman A.F.M., Anderson R.H. Formation of the tricuspid valve in the human heart. Circulation 1995;91:111-121.[Abstract/Free Full Text]
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Van den Hoff M.J., Moorman A.F.M., Ruijter J.M., et al. Myocardilization of the cardiac outflow tract. Dev Biol 1999;212:477-490.[Medline]
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Abstract
Introduction
