Pulmonary hemodynamics following reconstructive mitral valve surgery

The hemodynamic response in the immediate postoperative period after reconstructive mitral valve surgery was evaluated by means of cardiac output, pulmonary artery and left atrial pressures, pulmonary blood volume and pulmonary vascular resistance using indwelling catheters in the pulmonary artery and left atrium. Elevated pulmonary artery pressure returned to near-normal levels immediately after the correction of mitral stenosis by closed commissurotomy and mitral insufficiency by annuloplasty or valvuloplasty. Pulmonary artery and left atrial pressures returned to near-normal levels within 24 hours after surgery. In contrast, normalization of pulmonary artery and left atrial pressures were not conspicuous in cases of open commissurotomy. The difference could not be explained by the blood volume deficits, ischemic cardiac arrest during surgery, or residual valvular lesions. The most likely explanation appears to be due to further impairment of chronically diseased left ventricle by open heart surgery and increased water load after hemodilution perfusion which leads to interstitial pulmonary edema. Comparison between the pulmonary artery, left atrial pressures and cardiac output suggested that keeping pulmonary artery mean pressure below 35 mmHg. and left atrial mean pressure below 15 mmHg. are important to maintain optimum cardiac output without causing interstitial pulmonary edema in the immediate postoperative period after mitral valve surgery.