Nitric oxide and prostacyclin as test agents of vasoreactivity in severe precapillary pulmonary hypertension: predictive ability and consequences on haemodynamics and gas exchange

Abstract

Abstractmay make it a more appropriate agent for testing the vasodilator response. Background -In patients with primary (Thorax 1997;52:369-372) pulmonary hypertension who respond to vasodilators acutely, survival can be im- Keywords: pulmonary hypertension, vasodilators, nitric proved by the long term use of calcium oxide, prostacyclin, calcium channel blockers. channel blockers. However, testing for such a response with calcium channel blockers or prostacyclin (PGI 2 ) may causeIn patients with primary pulmonary hyperhypotension and adversely affect gas extension an improvement in survival can be change. Nitric oxide (NO), which does not obtained by the long term administration of have these effects, could be a better test calcium channel blockers to those who respond agent.to vasodilators given acutely. 1 Calcium channel Methods -NO (10, 20, and 40 ppm for blockers have been used for this test procedure, 15 minutes), PGI 2 (1->10 ng/kg/min), and but their effect on systemic haemodynamics can oral nifedipine (10 mg, then 20 mg/h) were induce severe or even life threatening effects. 2 administered sequentially to 10 patients Because of its short half life and pulmonary after determination of the 24 hour spon-vasodilator effect, prostacyclin (PGI 2 ) has been taneous variability of their pulmonary and administered instead and is regarded as the systemic mean arterial pressures. Patients screening agent of choice.3 However, PGI 2 is were considered responders if the mean an equally potent systemic vasodilator and may pulmonary artery pressure or pulmonary impair pulmonary hypoxic vasoconstriction vascular resistance decreased by 20% or with resulting hypoxaemia. Recent studies have more.suggested that nitric oxide (NO), a selective Results -Six patients (60%) responded to pulmonary vasodilator, may be a better screenall three agents, and three to none of the ing agent.4 5 The purpose of the present study agents. One patient responded to PGI 2 was to evaluate the ability of NO to predict a only. In those who responded to vaso-response to calcium channel blockers, and to Medical ICU Division dilators, NO had no major effect on gas compare its effects on haemodynamics and gas venous blood samples were collected sim-ues of PAPspont for the responders were compared with those of the decrease in mean ultaneously for blood gas determinations. Derived variables were computed according to PAP obtained with each vasodilator using a Wilcoxon signed rank test. standard equations.Since a previous study from our ICU demonstrated a 24 hour variability of 11% in mean PAP and 14% in pulmonary vascular resistance ResultsAll results are expressed as mean (SD). Ten (PVR) in patients with pulmonary hypertension, in the absence of any drug ad-patients were studied, four of whom had primary pulmonary hypertension while in the others ministration, 7 these parameters were first recorded every hour for 24 hours without any pulmonary hypertension was associated with cirrhosis and portal hypertension (2), conpharmacological intervent...

Lung cGMP release subsequent to NO inhalation in pulmonary hypertension: respondersversusnonresponders

“…Pharmacological challenge with inhalative NO, a short-acting vasodilatory agent possessing selectivity for the pulmonary circulation, is now largely accepted as a convenient tool to detect patients with a good acute responsiveness to vasodilators [5,19]. It has previously been shown that haemodynamic responsiveness to inhaled NO is a good predictor for a beneficial response to high-dose oral calcium channel blockers [19,20].…”

“…In contrast, such pharmacological therapy may be hazardous in haemodynamic "nonresponders" [4] and is therefore discouraged. Instead of directly testing with calcium channel blockers during right heart catheterization, vasoreactivity testing with inhaled nitric oxide (NO), being advantageous due its very short half-life and its selectivity for the pulmonary vasculature, is a widely-accepted procedure for detecting patients who are eligible for high-dose calcium channel blocker therapy [4][5][6].…”

Pulmonary vasoreactivity testing in diagnosis and prognosis of pulmonary hypertension

“…10 hastanın yer aldığı ve eski PVT test kriterlerinin kullanıldı-ğı bir çalışmada ise nifedipin, iNO ve epoprostenol ile uygulanan teste tüm hastaların %60'ı yanıt vermiş ancak iNO'ya göre nifedipin ve epoprostenol daha fazla yan etkiye neden olmuştur (PaO2, kan basıncı ve SVD'de düşme) (46). iNO'ya karşı adenozin Brezilya'dan yapılan yeni bir çalışmada Oliveira ve ark.…”

Sildenafil no tratamento da hipertensão arterial pulmonar idiopática em crianças e adolescentes

“…This was carried out while patients breathed room air, after oxygen therapy at 100% for 15 minutes and use of nitric oxide in an initial concentration of 10 ppm; in the absence of response, the concentration was increased every 10 minutes, up to 80 ppm. 6 Oral nifedipine was initially given in the dose of 5 mg to patients weighing more than 30 kg and in the dose of 0.2 mg/kg to children, with a 50% increase in the dose every 6 hours in case of no response or of side effects. Pulmonary reactivity tests were defined as positive in the presence of a decrease greater than 20% in mean PP, without reduction of systemic output and with maintenance of the reduction in the pulmonary systolic pressure (PSP)/systolic arterial pressure (SAP) ratio greater than 20%.…”

“…It is common knowledge that most patients do not respond to calcium antagonists and may have severe side effects, which shows the importance to perform acute reactivity tests in order to select those patients who would definitely benefit from their use. Pulmonary reactivity tests employ oxygen at 100% and short half-life drugs with pulmonary vasodilatory action, such as adenosine, 5 prostacyclin, 6 acetylcholine and mainly nitric oxide, 7 since it is a selective and short-acting pulmonary vasodilator.…”