Aortic root replacement with ventricular septal extension (The Konno Procedure)

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

Aortic stenosis causes progressive left ventricular hypertrophy with associated sequelae of decreased ventricular function and myocardial ischemia. These factors place the patient at increased risk for sudden death. Exercise intolerance and exertional dyspnea can occur in patients with severe forms of aortic valve disease. When obstruction to the outflow of blood from the left ventricle to the aorta includes aortic valve annular hypoplasia and subvalvar obstruction, traditional aortic valve replacement may not be possible. In such cases, enlargement of the aortic valve annulus can be carried out by extending an anterior incision through the annulus of the aortic valve into the ventricular septum. Aortic root replacement can then be performed with a cryopreserved, valved aortic homograft, a pulmonary autograft, or a mechanical aortic valve prosthesis.

Surgical technique

Aortic root replacement with ventricular septal defect illustration

Aortic root replacement with extension into the ventricular septum requires cardiopulmonary bypass and aortic cross-clamping. The native aortic root is excised, with careful attention to excision of the coronary arteries as buttons with adjacent aortic wall. Next, the left ventricular outflow tract is opened widely by incising into the ventricular septum. A cryopreserved, valved aortic homograft, pulmonary autograft, or mechanical aortic valve prosthesis is inserted into the newly opened left ventricular outflow tract. When a homograft or autograft is used, the neo-aortic root is stitched to the native aortic annulus, and the coronary artery buttons are implanted into the base of the graft. The distal end of the graft is then sutured to the distal native aorta.

Transesophageal echocardiography and intracardiac pressure measurements are performed to evaluate the adequacy of repair. Aortic cross-clamp time and cardiopulmonary bypass time required to complete repair are moderate to long.

Postoperative considerations

The postoperative course following the Konno aortic root replacement procedure is usually uneventful. 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. This is an extensive operation. Hemodynamic instability in the early postoperative period is sometimes encountered. Excessive postoperative bleeding is a potential complication since the surgical site includes suture lines exposed to systemic pressure. Abnormalities of atrioventricular conduction can occur due to manipulation or incisions at the site of ventricular septal extension. Atrioventricular pacing capability should be readily available. Postoperative intracardiac pressures and arterial oxygen saturation should be normal. Length of hospital stay following repair averages 5 to 7 days.