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We report the cases of 2 pediatric patients who had Shone complex. Each child had severe left ventricular outflow tract obstruction and marginal mitral obstruction, and both underwent the Ross-Konno operation. The mitral valve was left alone. Both patients survived the operations, and serial follow-up echocardiography up to 4 years later showed a decreased or decreasing trend in the peak mitral diastolic velocity. The Ross-Konno procedure can be an acceptable approach for a subgroup of patients who have Shone complex.
Shone complex,1 which involves congenital left-heart obstructions at multiple levels, is a surgical challenge. There is no corrective surgery for left ventricular inflow obstruction or mitral stenosis in growing patients; therefore, mitral stenosis is the primary determinant of long-term outcome.2 On the other hand, the left ventricular outflow tract (LVOT) obstruction can be treated with the Ross or the Ross-Konno procedure. Shone complex encompasses a broad anatomic and physiologic spectrum, ranging from mild lesions that may not require any intervention to severe lesions that inevitably require Norwood–Fontan pathways. In a subset of patients who have Shone complex, only LVOT obstruction requires surgical intervention for biventricular repair, and the mitral stenosis is mild enough to leave untouched. Recent refinements in surgical technique have overcome the high complexity of the Ross-Konno procedure for isolated LVOT obstruction. The appropriateness of this procedure for patients with Shone complex, however, has yet to be proved. Here, we report the cases of 2 patients in whom the Ross-Konno procedure was performed.
In 2004, 2 patients with Shone complex underwent the Ross-Konno procedure in our hospital. At the time of operation, patient 1 was a 4-year-old girl (weight, 15.7 kg), and patient 2 was a 5-year-old boy (weight, 17.8 kg). Both had had significant aortic coarctation (at 2 weeks and at 6 months of age, respectively) and had undergone aortic arch reconstruction that involved resection and an extensive end-to-end anastomosis technique. Patient 1 subsequently underwent open aortic valvotomy for aortic valve stenosis at 6 months of age. Both patients had been asymptomatic thereafter.
Preoperative evaluation with echocardiography and catheterization showed peak systolic velocities (pressure gradients) across the LVOT of 4.9 m/sec (110 mmHg) and 3.2 m/sec (53 mmHg), respectively. Both patients had moderate mitral stenosis, with peak diastolic velocities of 2.3 m/sec and 2 m/sec, respectively (Fig. 1). Their mitral valve sizes were quite small, with Z values of the mitral valve annulus diameter of −3 and −1.7, respectively. Patient 1 had a parachute mitral valve, with all chordae tendineae inserted into the posteromedial papillary muscle. In patient 2, the mitral valve morphology was normal; however, both the anterior and posterior leaflets had restricted motion.
The Ross-Konno operation was performed with a full-root technique in both patients. Pulmonary autograft muscle extensions were used to augment the incised ventricular septa. The mitral valve had a single dominant papillary muscle in patient 1, and it was structurally normal in patient 2. A 19-mm Freestyle® porcine valve conduit (Medtronic, Inc.; Minneapolis, Minn) was used in the right ventricular outflow tract reconstruction. After cardiopulmonary bypass was stopped, transesophageal echocardiography showed moderate mitral stenosis and no residual LVOT obstruction. The patients' postoperative recoveries were quick, and they remained asymptomatic. Serial follow-up echocardiography showed a decreasing trend in peak mitral diastolic velocities during the follow-up period of 4 years or more (Fig. 1).
There have been only a few previous reports of the Ross-Konno procedure's being performed in patients with Shone complex, partly because it is a technically demanding procedure for severe left ventricular lesions.3–5 The implanted valve at the aortic position may have some mass effect, and it may push the mitral annulus from the anterior. In the Shone-complex heart, small mitral valve size is an Achilles' heel, and the degree of mitral stenosis may deteriorate from subclinical to clinical due to the implanted LVOT mass. The pulmonary autograft is less bulky and less stiff than a valve prosthesis with an equivalent effective valve orifice, and the Ross-Konno procedure is superior to the Ross procedure from the mass-effect point of view.
Application of the Ross-Konno procedure in Shone patients is arguable. Prolonged myocardial ischemic time, cardiopulmonary bypass time, and incision of the ventricular septum could temporarily or permanently compromise left ventricular diastolic function and might increase early and late morbidity and death. Observation of the peak diastolic velocities in our 2 patients shows that this was not the case. Another issue is the long-term morbidity that is peculiar to the Ross procedure, including right ventricular outflow tract obstruction and pulmonary autograft dilation. Although there will certainly be a future need for reintervention in these growing patients, the risk of morbidity and death with it should be quite low.
Mitral valve growth after the Ross-Konno procedure is a source of concern. However, in our 2 patients, the mitral stenosis has improved, which could imply that the stenotic mitral valve has grown at least in proportion to somatic growth late after the procedure.
In conclusion, the Ross-Konno procedure may be an acceptable approach for a subgroup of patients who have Shone complex—even with severe LVOT—if the associated mitral stenosis is no more than moderate, because the marginally stenotic mitral valve might eventually grow and develop.
Address for reprints: Ryo Aeba, MD, Division of Cardiovascular Surgery, Keio University, 35 Shinanomachi, Shinjuku, Tokyo 160-8582, Japan