Late results of surgery for left ventricular outflow tract obstruction in children.

Forty-four patients, with a mean age at surgery of 10 years, were followed for 5 to 16 years (mean 9.7 years) after relief of left ventricular outflow tract obstruction. There were no early deaths, but 5 late deaths occurred, 3 following reoperation. Twenty-five patients were recatheterized from 1 to 16 years later (mean 6.6 years). In 21 of 32 patients (66 per cent), a new diastolic murmur followed relief of valvular stenosis; 25 (78 per cent) of these patients had a postoperative diastolic murmur. Seventeen of these 25 (68 per cent) were recatheterized, and 11 of the 17 (65 per cent) had moderate-to-severe aortic incompetence on angiography. Eight patients (18 per cent) have undergone reoperation and 9 more (20 per cent) will have to be reoperated upon soon. Although the aortic valve gradient and left ventricular stroke pressure were reduced in all obstructive types after surgery, left ventricular end-diastolic pressure significantly increased and cardiac index decreased after valvotomy. Cardiomegaly and electrocardiographic (ECG) abnormalities were present in 45 and 66 per cent, respectively, of all postoperative patients. Although 93 per cent of patients may be expected to survive and 82 per cent be reoperation free at 10 years, further surgery thereafter becomes increasingly common. Timely relief of obstruction prevents sudden death and produces excellent symptomatic improvement, but the operation is only palliative. Development of a reliable pediatric valve and ventriculo-aortic conduit may encourage earlier and more aggressive therapy.