Pulmonary Valvotomy

For pulmonary atresia with intact ventricular septum

A median sternotomy approach is used with mobilization and partial resection of the thymus gland. pericardiotomy is performed, and pericardium is harvested and cross-linked using glutaraldehyde. The patient is placed on cardiopulmonary bypass, usually performed by cannulating the ascending aorta and the right atrial appendage with a single venous drainage cannula. Efforts should be taken to allow the heart to remain beating by using a normothermic calcium-supplemented blood pump prime and allowing temperatures to drift to approximately 32°C only. At the institution of bypass the arterial duct is exposed and ligated. A longitudinal arteriotomy is made in the main pulmonary artery, above the valve level, and the valve is inspected. In the unusual case in which the anulus is adequate a valvotomy alone using sharp dissection opening the three identifiable commissures is all that is performed. The arteriotomy is subsequently closed with a running absorbable suture. In the more usual case inspection of the valve will reveal inadequate valve tissue and anulus, and the longitudinal arteriotomy incision will be taken across the anulus onto the right ventricular muscle. This incision is extended proximally until a clear opening into the right ventricular cavity is established. An oval glutaraldehyde-treated autologous pericardial patch or GoreTex is tailored to the right ventricular outflow tract incision and sewn to the two edges of the incision to create a right ventricular outflow tract with a diameter that is slightly smaller than normal (6 to 8 mm diameter for the average 3 to 4 kg body weight neonate).

Following this the patient’s temperature is returned to normal and attention is turned toward creating the systemic-to-pulmonary artery shunt if one is deemed necessary.

For critical neonatal pulmonary stenosis

Surgical relief of critical pulmonary stenosis is indicated in several circumstances. These include presentation of a patient to an institution without expertise in percutaneous balloon valvuloplasty and failure to achieve a successful balloon valvuloplasty, which typically will occur in the patient with only a "pinhole" opening in the valve.

Exposure is obtained by a median sternotomy. The thymus is mobilized but not removed and a longitudinal pericardiotomy is performed. The patient should be placed on cardiopulmonary bypass by cannulating the aorta and the right atrial appendage using a warm calcium-supplemented blood prime to allow continuous cardiac activity. Core temperature may be maintained at normothermic levels or allowed to drift only. At the institution of bypass the arterial duct is temporarily occluded with a snare. Active core cooling and aortic cross-clamping with or without cardioplegia should be avoided.

A longitudinal main pulmonary arteriotomy is performed to expose the pulmonary valve. The typical appearance of well-formed sinuses of Valsalva and fused commissures is studied and three careful commissurotomies are performed sharply, using a # 11 bladed scalpel to achieve a maximum orifice without causing unnecessary insufficiency. The valve leaflet motion may be restricted by tethering of the commissures to the sinus wall, and release of the leaflets may improve leaflet mobility. The arteriotomy is then closed and the patient is weaned from bypass. In critically ill neonates the approach should be to minimize the insult to the infant during the procedure by keeping the procedure simple and achieving the result as expeditiously as possible.

The excellent results achieved using balloon techniques in infants have demonstrated that concomitant shunts, transannular patches, infundibular muscle resections. and tricuspid valve procedures are not commonly necessary in the initial management of critical pulmonary stenosis. It seems prudent, however, not to permanently ligate the arterial duct at the time of the surgical valvotomy since this allows the flexibility of using prostaglandin E, to augment pulmonary blood flow in the first few days following the procedure, if necessary, until right ventricular compliance improves.

For pulmonary stenosis

Exposure is obtained by a median sternotomy. Following heparinization an aortic cannula is placed. For venous drainage in infants and children bicaval cannulation is preferred because in most patients presenting beyond the neonatal period the patent foramen ovale or atrial septal defect must be closed and in some infundibular resection may be needed. cardioplegia is generally avoided and patients are not actively cooled.

A transverse pulmonary arteriotomy is made above the valve. The fused commissures are identified and opened with a # 11 surgical blade and a tenotomy scissors. Any valvar tethering to pulmonary arterial wall is released. Quite often the thickened valve edges need excision (partial valvectomy). In dysplastic valves the thickened dysplastic portions of the valve are excised. The infundibular region should be inspected in all cases. In patients with significant dynamic infundibular obstruction obvious obstructing muscle bundles should be divided. In patients with associated fixed infundibular obstruction a more aggressive trans-pulmonary excision may be necessary. Occasionally a longitudinal subvalvar ventriculotomy is made and an infundibular patch is placed.

In patients with small anuli Hegar dilators are used to size the anulus intraoperatively. A transannular patch is used if the anulus is more than 2 to 3 standard deviations below normal or if the residual gradient is > 30 mm Hg.

After adequate relief of pulmonary stenosis, the heart is electrically fibrillated for a brief period to close the atrial communication. In patients with marked right ventricular dysfunction or hypoplasia it may be preferable to leave the foramen ovale open to promote right-to-left atrial shunting, thereby avoiding the sequelae of right ventricular failure.

The patient is weaned from cardiopulmonary bypass routinely. intraoperative transesophageal echocardiography can be very helpful in assessing the residual gradient, the degree of valve insufficiency, and the direction of flow at the atrial communication if one remains. It may be beneficial to perform a pull-back gradient following placement of a catheter across the valve under vision before closing the pulmonary arteriotomy.