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