Comparison of inhaled nitric oxide with aerosolized prostacyclin or analogues for the postoperative management of pulmonary hypertension: a systematic review and meta-analysis

Pulmonary artery denervation versus conventional therapies for PAH: a systematic review and updated network meta-analysis

AIMS

A recent guideline presented by the ESC Congress in 2022 had indicated a novel therapy targeted at pulmonary artery hypertension, known as pulmonary artery denervation (PADN), which get inspired from a laboratorial trial that could lowering the pulmonary artery pressure through the intervention on the animals. Our aim is to conduct a network meta-analysis to compare the efficacy and safety of PADN from six aspects with the current conventional therapies.

METHODS AND RESULTS

According to the PRISMA guidance, databases including Ovid, ClinicalTrials.gov, Medline, Embase, and PubMed were searched from inception to 22 August 2023, along with a full assessment of the previous five meta-analyses. Data were extracted and curated for Bayesian network meta-analysis. The primary outcome was the change in the 6-min walking distance (6MWD) from baseline with a secondary outcome called change in mean pulmonary artery pressure (mPAP) from baseline. The four safety outcomes included risk of clinical worsening, hospitalization, mortality and severe adverse events (SAEs). The comparison is structured on a contrast model based on 65 randomized controlled trials (RCTs) on PADN and the other conventional mainstream drugs. PADN had a better effect in improving 6MWD than Placebo (-77.76 m, 95% CI: -102.04 to -54.34 m), Macitentan (-65.32 m, 95% CI: -95.34 to -36.1 m), Bosentan (-64.5 m, 95% CI: -94.7 to -35.07 m), Iloprost (-62.66 m, 95% CI: -99.48 to -27.13 m), Oxygen (-62.42 m, 95% CI: -100.01 to -25.78 m), Treprostinil (-62.01 m, 95% CI: -89.04 to -35.61 m), Riociguat (-60.59 m, 95% CI: -86.11 to -35.98 m), Selexipag (-47.2 m, 95% CI: -85.61 to -10.19 m), Sildenafil (-44.92 m, 95% CI: -74.43 to -16.15 m), or Sitaxsentan (-39.53 m, 95% CI: -78.99 to -0.76 m). PADN had a better antihypertensive effect than placebo and showed statistical significant lower risks to induce clinical worsening and re-hospitalization than treprostinil, riociguat, and placebo groups. No statistically significant difference in risk of mortality and severe adverse events was observed between PADN versus the other interventions.

CONCLUSIONS

Compared with 16 types of conventional therapies and Placebo, PADN has advantage over nine single therapies and Placebo in improving 6MWD and appears to be better than two types of dual-drug combined therapies while with no statistical significance. PADN shows a favourable antihypertensive effect on mPAP and has a lower risk to trigger clinical worsening or hospitalization, while its risk on mortality and severe adverse events is still inconclusive.

Inhaled Pulmonary Vasodilators for the Treatment of Right Ventricular Failure in Cardio-Thoracic Surgery: Is One Better than the Others?

Right ventricular failure (RFV) is a potential complication following cardio-thoracic surgery, with an incidence ranging from 0.1% to 30%. The increase in pulmonary vascular resistance (PVR) is one of the main triggers of perioperative RVF. Inhaled pulmonary vasodilators (IPVs) can reduce PVR and improve right ventricular function with minimal systemic effects. This narrative review aims to assess the efficacy of inhaled nitric oxide and inhaled prostacyclins for the treatment of perioperative RVF. The literature, although statistically limited, supports the clinical similarity between them. However, it failed to demonstrate a clear benefit from the pre-emptive use of inhaled nitric oxide in patients undergoing left ventricular assist device implantation or early administration during heart-lung transplants. Additional concerns are related to cost safety and IPV use in pathologies associated with pulmonary venous congestion. The largest ongoing randomized controlled trial on adults (INSPIRE-FLO) is addressing whether inhaled Epoprostenol and inhaled nitric oxide are similar in preventing RVF after heart transplants and left ventricular assist device placement, and whether they are similar in preventing primary graft dysfunction after lung transplants. The preliminary analysis supports their equivalence. Several key points may be achieved by the present narrative review. When RVF occurs in the setting of elevated PVR, IPV should be the preferred initial treatment and they should be preventively used in patients at high risk of postoperative RVF. If severe refractory postoperative RVF occurs, IPVs should be combined with complementary pharmacology (inotropes and inodilators). If unsuccessful, right ventricular mechanical support should be established.

Safety and tolerability of continuous inhaled iloprost in critically ill pediatric pulmonary hypertension patients: A retrospective case series

Inhaled iloprost (iILO) has shown efficacy in treating patients with hypoxic lung disease and pulmonary hypertension, inducing selective pulmonary vasodilation and improvement in oxygenation. However, its short elimination half-life of 20-30 min necessitates frequent intermittent dosing (6-9 times per day). Thus, the administration of iILO via continuous nebulization represents an appealing method of drug delivery in the hospital setting. The objectives are: (1) describe our continuous iILO delivery methodology and safety profile in mechanically ventilated pediatric pulmonary hypertension patients; and (2) characterize the initial response of iILO in these pediatric patients currently receiving iNO. Continuous iILO was delivered and well tolerated (median 6 days; range 1-94) via tracheostomy or endotracheal tube using the Aerogen® mesh nebulizer system coupled with a Medfusion® 400 syringe pump. No adverse events or delivery malfunctions were reported. Initiation of iILO resulted in an increase in oxygen saturation from 81.4 ± 8.6 to 90.8 ± 4.1%, p < 0.05. Interestingly, prior iNO therapy for >1 day resulted in a higher response rate to iILO (as defined as a ≥ 4% increase in saturations) compared to those receiving iNO <1 day (85% vs. 50%, p = 0.06). When the use of iILO is considered, continuous delivery represents a safe, less laborious alternative and concurrent treatment with iNO should not be considered a contraindication. However, given the retrospective design and small sample size, this study does not allow the evaluation of the efficacy of continuous iILO on outcomes beyond the initial response. Thus, a prospective study designed to evaluate the efficacy of continuous iILO is necessary.

Pulmonary embolus associated with a rare provoking factor: recreational nitrous oxide use

Pulmonary embolism (PE) is a common acute presentation which may be provoked by multiple factors. We present the unique case of a young man with no underlying health conditions who was diagnosed with bilateral PE which we believe was provoked by chronic use of nitrous oxide (NO), a potentially under-recognised risk factor for PE. NO is a substance that is commonly used recreationally, particularly among young adults in the UK. It has been shown to increase serum homocysteine levels which may create a prothrombotic state.Our patient had raised serum homocysteine levels on admission. He was anticoagulated and discharged with advice to stop nitrous oxide use. We recommend asking patients about recreational drug use when screening for provoking factors for PE so as to offer appropriate treatment and counselling.

Recent advances on endogenous gasotransmitters in inflammatory dermatological disorders

•

Endogenous gasotransmitters nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H₂S), and potential candidates sulfur dioxide (SO₂), methane (CH₄), hydrogen gas (H₂), ammonia (NH₃) and carbon dioxide (CO₂), are generated within the human body.

•

Endogenous and potential gasotransmitters regulate inflammation, vasodilation, and oxidation in inflammatory dermatological disorders.

•

Endogenous and potential gasotransmitters play potential roles in psoriasis, atopic dermatitis, acne, and chronic skin ulcers.

•

Further research should explore the function of these gases and gas donors and inhibitors in inflammatory dermatological disorders.

Background

Endogenous gasotransmitters are small gaseous mediators that can be generated endogenously by mammalian organisms. The dysregulation of the gasotransmitter system is associated with numerous disorders ranging from inflammatory diseases to cancers. However, the relevance of these endogenous gasotransmitters, prodrug donors and inhibitors in inflammatory dermatological disorders has not yet been thoroughly reviewed and discussed.

Aim of review

This review discusses the recent progress and will provide perspectives on endogenous gasotransmitters in the context of inflammatory dermatological disorders.

Key scientific concepts of review

Endogenous gasotransmitters nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S) are signaling molecules that regulate several physiological and pathological processes. In addition, sulfur dioxide (SO₂), methane (CH₄), hydrogen gas (H₂), ammonia (NH₃), and carbon dioxide (CO₂) can also be generated endogenously and may take part in physiological and pathological processes. These signaling molecules regulate inflammation, vasodilation, and oxidative stress, offering therapeutic potential and attracting interest in the field of inflammatory dermatological disorders including psoriasis, atopic dermatitis, acne, rosacea, and chronic skin ulcers. The development of effective gas donors and inhibitors is a promising alternative to treat inflammatory dermatological disorders with controllable and precise delivery in the future.