Haemodynamic effects and potential clinical implications of inhaled nitric oxide during right heart catheterization in heart transplant candidates

Abstract

Aims Right heart catheterization (RHC) is indicated in all candidates for heart transplantation (HT). An acute vasodilator challenge is recommended for those with pulmonary hypertension (PH) to assess its reversibility. The effects of inhaled nitric oxide (iNO) on pulmonary and systemic haemodynamics have been reported only in small series. Our purpose was to describe the response to iNO in a larger population and its potential clinical implications. Methods and results From 210 RHC procedures performed between 2010 and 2019, vasodilator challenge with iNO was used in 108 patients, of which 66 had advanced heart failure undergoing assessment for HT (55±11 years old; 74.2% male gender; 43.9% ischaemic cardiomyopathy; left ventricular ejection fraction 28.4 ± 11,4%; and peak VO2 12.1 ± 3.0 mL/kg/min). iNO was administered through a tight-fitting facial mask regardless of baseline pulmonary pressures. Clinical endpoints (allcause mortality and acute right heart failure) were assessed according to baseline haemodynamic findings over the available follow-up period. There were no side effects from iNO administration. Typical response consisted of a reduction in pulmonary vascular resistance, consequent to an increase in left ventricular filling pressures, no significant change in mean pulmonary artery pressure (resulting in a lower mean transpulmonary gradient) and a mild increase in cardiac ouput. Pulmonary arterial compliance increased significantly, whereas systemic vascular resistance was only mildly affected. In five cases (7.6%), pulmonary vascular resistance increased paradoxically. All-cause mortality and post-HT right heart failure events were overall low and similar in patients without PH or reversible PH. Conclusions Vasodilator challenge with iNO is safe in advanced heart failure patients undergoing RHC prior to HT listing. It produces a reasonably predictable haemodynamic response, which occurs predominantly at the pulmonary circulation level. Clinical implications of iNO-induced reversibility may be relevant, but further systematic validation is warranted in larger cohorts.

Defining early right ventricular failure during left ventricular assist device implantation: Retrospective analysis of intraoperative management

“…[23] Inhaled nitric oxide can produce a 43% reduction in PVR and decrease transpulmonary gradient (TPG). [24] In our patients, 20-30 ppm nitric oxide was used in 38 (46.34%) patients. In addition, hypoxia, hypercarbia, and acidosis should be avoided to minimize PVR.…”

Comparison of levosimendan, NO, and inhaled iloprost for pulmonary hypertension reversibility assessment in heart transplant candidates

“…Inodilators such as milrinone, a bipyridine derivative type 3 phosphodiesterase inhibitor, have also been employed successfully for vasoreactivity testing with the advantage of convenient intravenous administration and lower incidence of systemic hypotension compared with simple vasodilators. 20 Using inodilators as an alternative to simple pulmonary vasodilators for vasoreactivity testing raises a key pathophysiological question, one could argue that selective pulmonary vasodilation without confoundment from cardiac performance would be desirable to ascertain whether pulmonary vascular resistances are fixed or irreversible, but it is highly questionable that this can be achieved in vivo even by the most selective pulmonary vasodilator due to concomitant load changes and reflex responses; thus, one may argue as well that the assessment of vascular resistance response should be carried out under optimized cardiac performance, 6,21 which means the highest achievable cardiac index at the lowest achievable left ventricular preload.…”

Nitric Oxide in Cardiac Surgery: A Review Article

“…iNO, in addition to conventional postoperative care, should be used as the initial therapy for pediatric heart disease and failure of the right side of the heart [ 248 ]. iNO is used to perform an acute vasoreactivity test to determine the operability of heart disease and heart transplant candidates [ 250 ]. Transient changes in pulmonary vascular tone may contribute to right ventricular dysfunction or hypoxemia in adult cardiac surgery; NO use is associated with improved right ventricular function and increased cardiac output, decreased pulmonary vascular resistance, decreased pulmonary artery pressure and optimized ventilation-perfusion matching [ 251 ].…”