Razzaq Zubia, Hussain Mazhar, Naqvi Shahab, Aslam Mohammad
Department of Physiology, Foundation University Medical College, Rawalpindi, Pakistan.
J Ayub Med Coll Abbottabad. 2009 Jul-Sep;21(3):106-10.
Variable response to inhaled nitric oxide (iNO) therapy in patients with mitral stenosis (MS) having pulmonary hypertension (PH) has been documented in early studies. The objectives of this study were to measure plasma Endothelin-1 (ET-1) levels in those patients and to correlate them with pulmonary vascular indices after iNO therapy. It was Quesi-experimental study.
Thirty patients with mitral or mixed mitral and aortic valve disease with severe pulmonary hypertension and enrolled for valve replacement surgery were included. Before the replacement, baseline pulmonary vascular indices and cardiac output were recorded. After the surgery, 10-20 ppm iNO was administered for 1 hour and all the parameters were again recorded. Patients were grouped into responders and non responders on the basis of % reduction in Pulmonary Vascular Resistance (PVR) after iNO therapy. Plasma ET-1 levels were measured in both groups by ELISA before and after the iNO therapy. Paired sample t-test was used to compare mean values for significance. The correlations between variables were then calculated by using Pearson's coefficient.
The plasma ET-1 levels were very high in all patients. They reduced in responders after iNO therapy; non-responders paradoxically showed significant increase in the levels of ET-1 after iNO therapy. Moreover, a positive correlation was observed in plasma ET-1 levels and post operative levels of PVR.
The correlation of changes in PVR and plasma ET-1 levels in responders suggests that high plasma ET-1 is a key mediator of poor response in PH secondary to MS, after iNO therapy.
早期研究已记录到二尖瓣狭窄（MS）合并肺动脉高压（PH）患者对吸入一氧化氮（iNO）治疗的反应存在差异。本研究的目的是测量这些患者的血浆内皮素-1（ET-1）水平，并将其与iNO治疗后的肺血管指标相关联。这是一项队列研究。
纳入30例患有二尖瓣或二尖瓣与主动脉瓣混合病变且伴有严重肺动脉高压并计划进行瓣膜置换手术的患者。在置换前，记录基线肺血管指标和心输出量。手术后，给予10 - 20 ppm的iNO持续1小时，并再次记录所有参数。根据iNO治疗后肺血管阻力（PVR）的降低百分比将患者分为反应者和无反应者两组。在iNO治疗前后，通过酶联免疫吸附测定法（ELISA）测量两组患者的血浆ET-1水平。采用配对样本t检验比较均值的显著性。然后使用Pearson系数计算变量之间的相关性。
所有患者的血浆ET-1水平都非常高。iNO治疗后反应者的ET-1水平降低；而无反应者在iNO治疗后ET-1水平反而显著升高。此外，观察到血浆ET-1水平与术后PVR水平呈正相关。
反应者中PVR变化与血浆ET-1水平的相关性表明，高血浆ET-1是iNO治疗后MS继发PH反应不佳的关键介质。
