Nitric Oxide Inhalationtherapy for Pulmonary Hypertension After Mitral Valve Surgery Does Not Shorten the Intubation Period and Length of Stay in the Intensive Care Unit: A Retrospective Study

Background Inhaled nitric oxide (NO) is often used postoperatively for pediatric pulmonary hypertension (PH). Although the use of postoperative inhaled NO for adult cases has become prevalent, the Asian data of such cases are limited. This study aimed to evaluate the safety and effectiveness of NO inhalation therapy for PH in adult patients after mitral valve surgery. Methods In this retrospective study, we enrolled 24 adult patients with a mean pulmonary artery pressure (mPAP) > 25 mmHg after mitral valve surgery at our institution from January 2017 to September 2020. Among these patients, NO was used postoperatively (NO group) in 13, whereas NO was not used in 11 (non-NO group). We compared the clinical data, such as age, preoperative echocardiogram, cardiac catheterization results, perioperative information, postoperative Swan-Ganz catheter data, tracheal intubation time, and length of stay in the intensive care unit (ICU). Results The NO group had higher tricuspid regurgitation pressure gradient, right atrial pressure, and pulmonary artery wedge pressure, as well as more surgically complex cases, than the non-NO group. There were no differences in operative and aortic cross-clamp time, tracheal intubation duration, or length of ICU stay. In the NO group, the mPAP decreased and the cardiac index increased after postoperative NO inhalation. However, there were no significant differences in the mPAP and cardiac index between the NO and non-NO groups. Conclusions Our results suggest that NO inhalation therapy was not associated with shorter postoperative intubation and ICU stay in adult patients with PH after mitral valve surgery. These findings support those of studies from other countries, yet they do not clarify the usefulness of inhaled NO in these cases. Optimal NO therapeutic strategies should be reconsidered with the goal of reducing intubation time and length of stay in the ICU.