Ann Thorac Surg 2003;76:1071-1072
© 2003 The Society of Thoracic Surgeons
Invited commentary
Michel N. Ilbawi, MD
The Heart Institute for Children, Hope Children’s Hospital, 4440 West 95th Street, Oak Lawn, IL 60453, USA
e-mail: nancy{at}thic.com
Interest in the hemodynamic effects of pulmonary regurgitation following tetralogy repair has evolved through the years. Early on, the prevailing concept was that regurgitation was benign, both early and late after surgery. Consequently, transannular patch to relieve right ventricular outflow obstruction was used liberally. Pulmonary regurgitation was accepted as a long term unimportant sequella of the repair. More recently, as a number of post repair patients are reaching adulthood, the deleterious effects of residual significant pulmonary regurgitation have become apparent. Excellent retrospective reviews such as reported by Warner and colleagues in this issue, suggest that selective preservation of pulmonary valve function at the time of repair or late after surgery may protect the right ventricle and justify the need for repeated valve replacements. Yet, in spite of such compelling data in support of normalizing pulmonary valve function following tetralogy repair, there has been no universal adoption of the concept.
One reason is the lack of long term prospective studies that analyze the contribution of a multitude of anatomic and hemodynamic variables that may modulate the deleterious effects of regurgitation, making it difficult to isolate it as an independent risk factor. Such variables include among others, the presence of RVOT aneurysm, myocardial dysfunction, residual distal pulmonary stenosis, hypoplasia of the pulmonary vascular bed, tricuspid valve regurgitation, and operative techniques. Timing of pulmonary valve insertion in post repair tetralogy is of extreme importance. It is another reason that may contribute to the apparent lack of uniformity in reported data and skepticism about the need for a competent valve. Aggressive early valve surgery may achieve excellent early and late results but may subject the patient to repeat surgeries, thus exchanging one disease process with another. On the other hand, benign neglect of, and delayed attention to pulmonary regurgitation may lead to irreversible ventricular dysfunction and negatively influence the outcome.
Several hemodynamic parameters were used to define the time for intervention, none of which has been uniformly endorsed. Progressive increase in indexed ventricular end diastolic dimensions may prove to be one of the most objective signs of early right ventricular decompensation and provide a window of opportunity to salvage the ventricle. Waiting for onset of symptoms or grossly abnormal excercise tests may be too late and is not likely to improve the patient’s long term outcome. Finally, accurate noninvasive assessment of right ventricular function to evaluate the long term benefit, if any, of valve replacement is lacking. Repeated cardiac catheterizations to study function is not justifiable. Newer imaging techniques using cardiac magnetic resonance angiography and three-dimensional echocardiography may provide a reliable and consistent parameter by which the post tetralogy patients can be followed up over a long period of time. Meanwhile, the dilemma surrounding the importance of the pulmonary valve is likely to continue.
