Acute Effects of Inorganic Nitrite on Cardiovascular Hemodynamics in Heart Failure With Preserved Ejection Fraction

Acute Effects of Inorganic Nitrite on Cardiovascular Hemodynamics in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a major public health problem that has no proven effective treatment. This study assessed the effects of acute nitrite administration on resting and exercise hemodynamics in patients with HFpEF.

Subjects were studied on their long-term medications in the post-absorptive state and supine position. Right heart catheterization was performed with simultaneous expired gas analysis at rest and during supine exercise at a 20 Watts workload for 5 minutes. After the first exercise phase (before any drug administration) and after return to steady-state baseline hemodynamic values, subjects were randomized. Study drug or placebo was infused for 5 minutes. After a 10 minute observation period, hemodynamic measurements were repeated at rest, followed by repeat supine exercise at a 20 Watts workload for 5 minutes, identical to the study's first phase. Arterial and venous blood samples and hemodynamic and expired gas data were acquired during each stage of the protocol.

Inclusion Criteria:

• Scheduled to undergo a cardiac catheterization procedure.
• Clinical symptoms of shortness of breath and fatigue
• Normal left ventricular ejection fraction (≥50%)
• Elevated left ventricular filling pressures at cardiac catheterization (defined as resting pulmonary capillary wedge pressure (PCWP)>15 mmHg and/or PCWP≥25 mmHg during exercise)

Exclusion Criteria:

• Systolic BP <120 mmHg
• Prior nitrate therapy (within previous 2 weeks)
• Glucose 6-phosphate dehydrogenase (G6PD) deficiency
• Other "non-HFpEF" specific causes of heart failure such as significant valvular disease (>moderate left-sided regurgitation, >mild stenosis), severe pulmonary disease, unstable coronary disease or coronary spasm, primary renal or hepatic disease, constrictive pericarditis, or infiltrative, restrictive, or hypertrophic cardiomyopathies