Comparison of intravenous sildenafil with inhaled nitric oxide for acute vasodilator testing in pulmonary arterial hypertension

Q: What are the key findings of this study?

Intravenous sildenafil demonstrated excellent hemodynamic agreement with inhaled nitric oxide for mean pulmonary artery pressure (ICC 0.903, 95% CI 0.809-0.949, p<0.001) during acute vasodilator testing.

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Group 1 pulmonary arterial hypertension (PAH) undergoing acute vasodilator testing (n=44). Intervention: Intravenous sildenafil vs. Inhaled nitric oxide 20 ppm for 10 min (administered prior to sildenafil in the same patients with a 15-min washout). Primary outcome: Systemic and pulmonary hemodynamic agreement (mean pulmonary artery pressure intraclass correlation and values) (ICC 0.903, 95% CI 0.809-0.949, p=<0.001).

Q: What does this research mean for the field?

Intravenous sildenafil demonstrates strong hemodynamic agreement with inhaled nitric oxide and serves as a feasible alternative agent for acute vasodilator testing in pulmonary arterial hypertension. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Shine Kumar; Danish Memon; Manu Raj; Amitabh Chanchal Sen; Jessin P. Jayasankar; Sreelakshmi P. Leeladharan; Abish Sudhakar; Raman Kumar

doi:10.1002/pul2.12180

October 1, 2022Pulmonary CirculationOpen Access

Comparison of intravenous sildenafil with inhaled nitric oxide for acute vasodilator testing in pulmonary arterial hypertension

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Key result

Intravenous sildenafil matches inhaled nitric oxide with excellent hemodynamic agreement during acute vasodilator testing.

ICC 0.903
95% CI 0.809-0.949
P<0.001
n=44

Figures

Why the study?

To determine the feasibility of intravenous sildenafil as an alternative to inhaled nitric oxide during acute vasodilator testing in pulmonary arterial hypertension.

Does intravenous sildenafil provide comparable systemic and pulmonary hemodynamic responses and acute responder identification compared to inhaled nitric oxide during acute vasodilator testing in patients with pulmonary arterial hypertension?

Study Design

Type

Cross-Sectional (n=44)

Multicenter

No

Structured PICO

Does intravenous sildenafil provide comparable systemic and pulmonary hemodynamic responses and acute responder identification compared to inhaled nitric oxide during acute vasodilator testing in patients with pulmonary arterial hypertension?

P

Population

44 treatment-naive children and adults (mean age 20.5 years, 61% female) with Group 1 pulmonary arterial hypertension or congenital heart disease undergoing acute vasodilator testing at a single tertiary center in South India.

I

Intervention

Intravenous sildenafil (ivS) 10 mg for adults and 0.25 mg/kg (up to a maximum of 10 mg) for children administered as a slow intravenous infusion over 10 minutes (after a 15-minute washout period following inhaled nitric oxide), with hemodynamics assessed 20 minutes post-infusion.

C

Comparator

Inhaled nitric oxide (iNO) 20 ppm with 25% fractional inspired oxygen delivered for 10 minutes via a closed circuit breathing system prior to sildenafil in the same patients.

O

Outcome

Systemic and pulmonary hemodynamic parameters (including mean pulmonary artery pressure [mPAP], mean aortic pressure [mAP], indexed pulmonary vascular resistance [PVRI], indexed systemic vascular resistance [SVRI], and PVRI:SVRI ratio) and their intraclass correlation (ICC) between intravenous sildenafil and inhaled nitric oxide during acute vasodilator testing.surrogate

Main Result

Effect estimate: ICC 0.903 (95% CI 0.809-0.949)

Absolute Event Rate: 49% vs 51.7%

p-value: p=<0.001

Intravenous sildenafil shows excellent hemodynamic correlation with inhaled nitric oxide and may serve as a safe, accessible alternative for acute vasodilator testing in pulmonary arterial hypertension, particularly in resource-limited settings.

Limitations

Use of Fick's method and the LaFarge table for systemic and pulmonary blood flow calculations has inherent drawbacks
Flowmeter-based iNO delivery has innate limitations since actual inspired concentration can vary due to breathing pattern, fresh gas flow rate, and rebreathing
Plasma levels of cGMP or sildenafil were not measured to demonstrate the effectiveness of drug administration
Small number of acute responders identified, requiring larger multicenter trials for validation
Flowmeter-based iNO delivery has innate limitations as actual inspired concentration can vary with breathing pattern, fresh gas flow rate, and rebreathing
Small number of acute responders (n=2), necessitating large multicenter trials for validation

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Implication

Supports consideration of intravenous sildenafil where inhaled nitric oxide is unavailable; leaves open prospective validation before routine adoption.

Abstract

Acute vasodilator testing (AVT) identifies acute responders for initiation of calcium channel blockers in pulmonary arterial hypertension (PAH) and operability in congenital heart disease (CHD). We sought to determine the feasibility of intravenous sildenafil (ivS) as an alternative to inhaled nitric oxide (iNO) in AVT. All patients with PAH undergoing cardiac catheterization for AVT (November 2015 to December 2020) were prospectively enrolled. Hemodynamic data were obtained at baseline, with iNO 20 ppm and ivS (0.25 mg/kg for children and 10 mg for adults). We studied 44 patients with a mean age of 20.5 ± 14.4 years (27 [61%] females and 20 [45%] children). There were 17 (38.6%) patients in the CHD group for operability assessment and 27 patients in non‐CHD group (idiopathic pulmonary arterial hypertension—16 [36.3%], residual PAH after shunt closure—7 [15.9%], and 2 cases [4.5%] each of familial PAH and portopulmonary hypertension). There was an excellent intraclass correlation for mean pulmonary artery pressures (0.903, 95% confidence interval, CI: 0.809–0.949, p < 0.001), mean aortic pressures (0.745, 95% CI: 0.552–0.858, p < 0.001), pulmonary vascular resistance index (0.920, 95% CI: 0.858–0.956, p < 0.001), systemic vascular resistance (SVR) index (0.828, 95% CI: 0.706–0.902, p < 0.001), and the ratio of pulmonary and SVR indices (0.857, 95% CI: 0.752–0.919, p < 0.001) between the two agents. There were two responders, both in non‐CHD group, and were identified by iNO and ivS. The hemodynamic effects of ivS show excellent correlation with iNO and could be a potential alternative agent for identifying acute responders during AVT.

Discussion

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Cite This Study

Kumar et al. (2022) conducted a cross-sectional in Group 1 pulmonary arterial hypertension (PAH) undergoing acute vasodilator testing (n=44). Intravenous sildenafil vs. Inhaled nitric oxide 20 ppm for 10 min (administered prior to sildenafil in the same patients with a 15-min washout) was evaluated on Systemic and pulmonary hemodynamic agreement (mean pulmonary artery pressure intraclass correlation and values) (ICC 0.903, 95% CI 0.809-0.949, p=<0.001). Intravenous sildenafil demonstrated excellent hemodynamic agreement with inhaled nitric oxide for mean pulmonary artery pressure (ICC 0.903, 95% CI 0.809-0.949, p<0.001) during acute vasodilator testing.

synapsesocial.com/papers/6a7072a8ce524a4339c42de5 https://doi.org/10.1002/pul2.12180

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Comparison of intravenous sildenafil with inhaled nitric oxide for acute vasodilator testing in pulmonary arterial hypertension

Figures

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Comparison of intravenous sildenafil with inhaled nitric oxide for acute vasodilator testing in pulmonary arterial hypertension

Figures

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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