Ann Thorac Surg 1995;60:1249
© 1995 The Society of Thoracic Surgeons
Invited Commentary
Invited Commentary
David A. Fullerton, MD
Cardiothoracic Surgery, University of Colorado Health Sciences Center, Box C-310, 4200 E Ninth Ave, Denver, CO 80262
See also page 1245.
Pulmonary hypertension secondary to increased pulmonary vascular resistance (PVR) is one of the most important determinants of operative morbidity and mortality as well as long-term survival after repair of a left-to-right shunt. Such pulmonary hypertension is derived from the structural remodeling of the pulmonary vascular bed (``fixed'' component of PVR) and from pulmonary vasoconstriction (``reactive'' component of PVR). Because surgical repair of the shunt is usually contraindicated if the increased PVR is ``fixed,'' preoperative pharmacologic provocation (oxygen, inhaled nitric oxide, or intravenous vasodilators) should be undertaken in the cardiac catheterization suite in an attempt to vasodilate the pulmonary circulation. If the increased PVR is found to be ``reactive,'' the shunt may usually be closed, but the risk of surgical repair is augmented. Acute right heart failure secondary to exacerbated pulmonary vasoconstriction may be fatal perioperatively. The pulmonary vasoconstrictive effects of cardiopulmonary bypass are well appreciated, and perioperative changes in acid–base status, oxygenation, circulating catecholamines, may precipitate a pulmonary hypertensive crisis.
The very innovative technique described by Dr Zhou and colleagues appears to permit a controlled right-to-left shunt in the early perioperative period to avoid acute right heart failure. The echocardiographic data confirm the unidirectional patch functioned as designed, and the investigators successfully applied the technique in 24 high-risk patients with excellent results. This technique is analogous to the fenestrated Fontan procedure, and may offer a significant advantage in the surgical repair of intracardiac shunts in patients with pulmonary hypertension.
Before using this technique, the surgeon must be confident that a large portion of the PVR is ``reactive''; closure of a right-to-left shunt that is needed to decompress the right heart (Eisenmenger's syndrome) may be fatal. As demonstrated by Dr Zhou and colleagues, the technique may be most valuable in providing a temporary ``pop-off'' valve for the right heart until a right-to-left shunt is no longer needed. The excellent results of this series suggest that the unidirectional valve patch technique may be a valuable surgical tool.
Related Article
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Unidirectional Valve Patch for Repair of Cardiac Septal Defects With Pulmonary Hypertension
- Qiwen Zhou, Yongqiang Lai, Hua Wei, Ruiming Song, Yafeng Wu, and Hong Zhang
Ann. Thorac. Surg. 1995 60: 1245-1248.
[Abstract]
[Full Text]
