• Zubia Razzaq
  • M, Mazhar Hussain
  • Shahab Naqvi
  • Mohammad Aslam


Background: 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 thisstudy were to measure plasma Endothelin-1 (ET-1) levels in those patients and to correlate them withpulmonary vascular indices after iNO therapy. It was Quesi-experimental study. Methods: Thirtypatients with mitral or mixed mitral and aortic valve disease with severe pulmonary hypertension andenrolled for valve replacement surgery were included. Before the replacement, baseline pulmonaryvascular indices and cardiac output were recorded. After the surgery, 10–20 ppm iNO was administeredfor 1 hour and all the parameters were again recorded. Patients were grouped into responders and nonresponders 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. Pairedsample t-test was used to compare mean values for significance. The correlations between variableswere then calculated by using Pearson’s coefficient. Results: The plasma ET-1 levels were very high inall patients. They reduced in responders after iNO therapy; non-responders paradoxically showedsignificant increase in the levels of ET-1 after iNO therapy. Moreover, a positive correlation wasobserved in plasma ET-1 levels and post operative levels of PVR. Conclusion: The correlation ofchanges in PVR and plasma ET-1 levels in responders suggests that high plasma ET-1 is a keymediator of poor response in PH secondary to MS, after iNO therapy.Keywords: Mitral Stenosis, Pulmonary Hypertension, Inhaled Nitric Oxide


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