Surgical Approaches and Management
There is currently no consensus regarding the management of multiple muscular septal defects, particularly concerning the timing and type of interventions. For those with pulmonary hypertension and congestive cardiac failure, medical management alone is ineffective. It follows that those diagnosed with multiple defects at an early age, with symptoms of congestive cardiac failure and/or pulmonary hypertension, and with volume overload of the left ventricle, should undergo surgical or hybrid intervention to prevent ventricular dilation and dysfunction, arrhythmias, aortic regurgitation, and ongoing pulmonary hypertension.35,36 The urgency of intervention will be determined primarily by the severity of presenting symptoms, and by the associated cardiac anomalies if present. The finding of the Swiss-cheese septum, along with major associated cardiac lesions, significantly increases the risks of operation. Such patients are managed on an individual basis.2-13
Surgical management has evolved with time. Moderately hypothermic cardiopulmonary bypass at 32°C, with cold cardioplegia, is now the most popular technique. Several investigators have used deep hypothermic circulatory arrest for patients with low body weight, complicated anatomy, and/or associated congenital cardiac malformations.6-8,43 The mean duration of circulation arrest was 40 minutes, with a range of 20-60 minutes.6-8,43
Various imaging techniques have proven their value for intraoperative identification of the defects. Either cross-sectional or three-dimensional color Doppler echocardiography, including transesophageal imaging, and echocardiographic en-face reconstruction of the right ventricular septal surface, have emerged as superior diagnostic modalities.1-72
While the general approach to multiple muscular septal defects is similar to that of isolated ventricular septal defects, their presence poses particular challenges for their identification and closure. As a consequence, a wide range of therapeutic approaches have been described.
When multiple defects are located in the muscular septum, oozing of blood can be demonstrated through the defects into the right ventricle despite adequate left ventricular venting. Several maneuvers have been used to identify the defects, including intraoperative epicardial echocardiography. When using a transtricuspid approach, larger defects can easily be located via the tricuspid valve. A blunt tip right angled forceps can be placed gently through the hole, without using any force except for the weight of the angled clamp. A DeBakey forcep is then held in the left ventricle, either placed through the larger inlet muscular defect, or via an atrioseptostomy. The metallic sound of two metal tips touching each other indicates that the right angled clamp has successfully been placed through the second defect. Either a No.3 Sutupak silk suture, or a No.8 Foley catheter, can be looped through the additional septal defects to facilitate closure (Figures 5A-5F).
Most investigators have performed postoperative transesophageal echocardiography and saturation determination. Large residual shunts detected intraoperatively with a pulmonary-to-systemic blood flow ratio of greater than 2, have been managed either by reinstitution of bypass and reexamination of the ventricular septum, or by hybrid device closure.7,20-24,28-32,45
Although catheter-based techniques appear promising, they are not yet widely used to close the entire spectrum of multiple septal defects in all age groups. For the time being at least, surgical repair remains the gold standard.1-26
On the basis of our initial review, we have sought, as far as possible, to assess the therapeutic options according to the specific anatomical combinations of defects. Each option, of course, may further be tailored according to the needs of the individual patient and surgeon.
Multiple discrete muscular defects
Several options have been suggested, although each option may be tailored to the individual patient, and surgeon. The decision to embark upon a one-stage repair rests with the surgeon, who must decide whether all significant defects can safely be closed. Should the repair be unsuccessful, leaving a residual shunt of greater than 1.5:1, after a prolonged pump run and potential associated myocardial ischemia, a difficult postoperative course, and death can be expected. Placement of a band on the pulmonary trunk allows for growth before attempted surgical or interventional closure. Ventricular hypertrophy, furthermore, may result in closure of smaller defects.16,17,38-40