Pulmonary hypertension is characterized by an increase in vascular tone of an abnormal proliferation of muscle cells in the wall of small pulmonary arteries. Endothelin-1(ET-1) is a potent endothelium-derived vasoconstrictor peptide with important mitogenic properties. It has been recognized that endothelin-1 may contribute to increase in pulmonary arterial tone or smooth muscle proliferation in congenital heart disease patients with pulmonary hypertension. To explore the role of endothelin-1 in patent ductus arterious, we measured endothelin-1 before and after closure of ductus in artery and vein plasma.

Seven patients of patent ductus arteriosus underwent thoracoscopic clipping of dustus in 1997 June-August. Their age was 1-24 months and male 4, female 3. Blood samples were drawn from radial artery and inferior vena cava before, 30 minutes and 90 minutes after closure of ductus. Endiothelin-1 was measured by radioimmunoassay method.

Arterial endothelin-1 was 17.96±8.09pg/ml at before closure of ductus, 13.47±3.14pg/ml at 30 minutes after closure of ductus and 11.43±2.9pg/ml at 90 minutes after closure of ductus. Venous endothelin-1 was 9.34±3.55pg/ml at before closure, 8.9±3.74pg/ml at 30 minutes after closure and 8.4±3.71pg/ml at 90minutes after closure of ductus. Arterial endo-thelin-1 was significantly higher than venous one at before and 30 minutes after ductus closure(p<0.05). Arterial endothelin-1 at 90 minutes after ductus closure was significantly lower than that at before the closure(p<0.05).

Patients pf patent ductus arteriosus have substantial alterations in plasma endo-thelin-1 which is decreased after closure of ductus. Comparing with venous plasma, the higher levels of ET-1 in arterial plasma suggest pulmonary production of endothelin-1, which may contribute to induce pulmonary hypertension.

Surgical closure of patent ductus arterious(PDA) by lateral thoracotomy is considered as a standard therapy. But large incision, muscle cutting and chest pain are problematic. So I used two less invasive techniques : minithoracotomy and video-assisted thoracoscopic surgery. I tried to compare the results of them.

I reviewed the clinical records and operative reports of 22 children patients who were treated surgically between Jan. 19996 and Dec. 1996. Ten patients underwent Minithoracotomy(MT) and twelve patients Video-assisted thoracoscopic surgery(VATS). All of them were used tithanium clipping for closure of PDA.

Both groups were similar in age, body weight, Echocardiographically estimated size of PDA and Qp/Qs. All procedures were performed uneventfully. Operative time averaged 104±26 minutes for MT versus 96±31 minutes for VATS. Mean hospital stay was 7.2±1.7 days for MT and 4.6±1.2 days for VATS(p<0.05}. Postoperative hoarseness was occured in one patient(MT group) but was transient. There was no case with residual shunt confirmed by echocardiography.

Minithoracotomy and Video-assisted thoracoscopic surgery were as effective as lateral thoracotomy for closure of patent ductus arteriosus. Operative times were similar in two techniques but hospital stays were shorter in VATS group. Both MT and VATS techniques are effective and less invasive but I advocate VATS technique is more beneficial in terms of hospital stay and cosmetic aspect.