Double outlet right ventricle

Provided by "Pediatric Heart Surgery — a reference for professionals" 

Pathophysiology

Double outlet right ventricle is characterized by both great vessels arising predominantly from the right ventricle. This cardiac anomaly represents a broad spectrum of anatomic subtypes. A ventricular septal defect is nearly always present, and its location may be variable. Infundibular and valvar pulmonic steno- sis, as well as valvar and subvalvar aortic stenosis, are commonly associated lesions. The broad spectrum of anatomic subtypes represented makes the physiologic abnormalities equally variable. Double outlet right ventricle may present with a large left-to-right shunt and congestive heart failure, or the patient may present with cyanosis due to pulmonary stenosis.

Surgical technique

Repair of double outlet right ventricle requires cardiopulmonary bypass and aortic cross-clamping. Intracardiac repair of this defect is performed through either a right ventriculotomy or a right atriotomy. The ventricular septal defect is closed with a synthetic patch to direct left ventricular outflow to the aortic valve without obstruction. This large intracardiac patch may encroach upon the right ventricular outflow tract. It is for this reason that a patch of synthetic material or a cryopreserved, valved pulmonary homograft is used to provide unobstructed continuity from the right ventricle to the pulmonary artery. Transesophageal echocardiography is used to help assess the adequacy of repair. Cardiopulmonary bypass time and aortic cross-clamp time required to repair double outlet right ventricle are moderate to long, depending on the individual anatomy.

Postoperative considerations

The postoperative course following repair of double outlet right ventricle is variable since a diverse group of anatomic subtypes is represented. Invasive monitors used include arterial and central venous catheters. An LA line is used when needed for hemodynamic management. LA pressure acts as a surrogate for left ventricular end diastolic pressure, an excellent indicator of left ventricular performance. Non-invasive monitors include NIRs (near infrared spectroscopy) probes to assess adequacy of regional and global perfusion and traditional pulse oximetry. Vasoactive agents might include epinephrine and/ or milrinone. Numerous other agents are available and are tailored to the specific needs of the patient, targeting adequate oxygen delivery to the tissues of the body and optimization of cardiac output. Excessive postoperative bleeding is an uncommon complication following this repair. Atrioventricular rhythm disturbance is a potential complication, as surgical manipulation is performed near the atrioventricular conduction system during VSD closure. Atrioventricular pacing capability should be readily available. Low cardiac output is an uncommon postoperative complication, but it is more likely in patients with more complex anatomic subtypes. Following satisfactory repair of double outlet right ventricle, there should be no obstruction to outflow from either ventricle, and intracardiac pressures should be normal. Arterial oxygen saturations should be normal. Length of hospital stay averages 7 to 10 days.