Matching Perfusion and Metabolic Activity in HFpEF

Study Overview
=================
Brief Summary
-----------------
This study will test whether pharmacologic agents that increase perfusion [Potassium Nitrate (KNO3)], with and without additional supplements that may improve mitochondrial function [Propionyl-L-Carnitine (PLC) and Nicotinamide Riboside (NR)], improve submaximal exercise endurance and skeletal muscle oxidative phosphorylation capacity (SkM OxPhos) in participants with Heart Failure with Preserved Ejection Fraction (HFpEF).

Detailed Description
-----------------
This study will test whether Potassium Nitrate (KNO3), with and without Propionyl-L-Carnitine (PLC) and Nicotinamide Riboside (NR), improves submaximal exercise endurance and skeletal muscle oxidative phosphorylation capacity (SkM OxPhos) in participants with Heart Failure with Preserved Ejection Fraction (HFpEF). Additionally, the study will test whether the response to supplemental oxygen during a standardized MRI assessment of skeletal muscle oxidative capacity can identify HFpEF individuals who preferentially will benefit from either KNO3 alone or the combination of pharmacologic agents (KNO3 + PLC + NR)

Official Title
-----------------
Matching Perfusion and Metabolic Activity in HFpEF

Conditions
-----------------
Heart Failure With Preserved Ejection Fraction

Intervention / Treatment
-----------------
* Drug: Potassium Nitrate
* Drug: Potassium Nitrate + Propionyl-L-Carnitine + Nicotinamide Riboside
* Other: Potassium Chloride


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: NYHA Class II-III symptoms Left ventricular ejection fraction >= 50% Stable medical therapy for at least 1 month Prior or current evidence for elevated filling pressures as follows: a. Mitral early (E)/mitral septal tissue annular (e') velocity ratio > 8, in the context of a septal e' velocity <=7, in addition to one of the following: i. Large left atrium (LA volume index > 34 mL/m2) ii. Chronic loop diuretic use for control of symptoms iii. Elevated natriuretic peptides within the past year (e.g. NTproBNP > 125 pg/mL in sinus rhythm or > 375 pg/mL if in atrial fibrillation) b. Mitral E/e' ratio > 14 at rest or during exercise c. Elevated invasively-determined filling pressures previously (resting left ventricular end-diastolic pressure >= 16 mm Hg or pulmonary capillary wedge pressure >= 15 mmHg; or PCWP/LVEDP >= 25 mmHg with exercise) d. Prior episode of acute heart failure requiring IV diuretics Exclusion Criteria: Age <18 years old Pregnancy: Treatment with organic nitrates or phosphodiesterase inhibitors that cannot be interrupted Uncontrolled atrial fibrillation, as defined by a resting heart rate > 100 beats per minute at the time of the baseline assessment Hemoglobin < 10 g/dL Subject inability/unwillingness to exercise Moderate or greater left sided valvular disease (mitral regurgitation, aortic stenosis, aortic regurgitation), mild or greater mitral stenosis, severe right-sided valvular disease Known hypertrophic, infiltrative, or inflammatory cardiomyopathy Clinically significant pericardial disease, as per investigator judgment Current angina due to clinically significant epicardial coronary disease, as per investigator judgment Acute coronary syndrome or coronary intervention within the past 2 months Primary pulmonary artery hypertension (WHO Group 1 Pulmonary Arterial Hypertension) Clinically significant lung disease as defined by: Chronic Obstructive Pulmonary Disease meeting Stage III or greater GOLD criteria (FEV1<50%), treatment with oral steroids within the past 6 months for an exacerbation of obstructive lung disease, current use of supplemental oxygen aside from nocturnal oxygen for the treatment of obstructive sleep apnea, desaturation to <90% on the baseline maximal effort cardiopulmonary exercise test Clinically-significant ischemia, as per investigator's judgement, on stress testing without either (1) subsequent revascularization, (2) an angiogram demonstrating the absence of clinically significant epicardial coronary artery disease, as per investigator judgment; (3) a follow-up 'negative' stress test, particularly when using a more specific technique (i.e., a negative perfusion imaging test following a 'positive' ECG stress test) Left ventricular ejection fraction < 45% on a prior echocardiogram or cardiac MRI Significant liver disease impacting synthetic function or volume control (ALT/AST > 3x ULN, Albumin < 3.0 g/dL) eGFR < 30 mL/min/1.73m^2 Methemoglobin > 5% Serum potassium > 5.0 mEq/L Severe right ventricular dysfunction Baseline resting seated systolic blood pressure > 180 mmHg or < 100 mmHg Orthostatic blood pressure response to the transition from supine to standing (>20 mmHg reduction in systolic blood pressure 2-3 minutes after standing) Active participation in another study that utilizes an investigational agent (observational studies/registries allowed) Any condition that, in the opinion of the investigator, will interfere with the performance and completion of the study. Contraindications to MRI

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: 3 interventions will be randomized and administered in a double-blind fashion
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Potassium Nitrate<br>Potassium Nitrate (KNO3) 6 mmol three times daily | Drug: Potassium Nitrate<br>* Potassium Nitrate is the active intervention that may increase blood flow to exercising muscle<br>* Other names: KNO3;|
| Active Comparator: Potassium Nitrate + Propionyl-L-Carnitine + Nicotinamide Riboside<br>Potassium Nitrate (KNO3) 6 mmol three times daily + Propionyl-L-Carnitine (PLC) 1000 mg twice daily + Nicotinamide Riboside (NR) 300 mg three times daily | Drug: Potassium Nitrate + Propionyl-L-Carnitine + Nicotinamide Riboside<br>* Potassium Nitrate + Propionyl-L-Carnitine + Nicotinamide Riboside will be used as a combination intervention to both increase blood flow (KNO3) and mitochondrial function (PLC + NR)<br>* Other names: KNO3 + PLC + NR;|
| Placebo Comparator: Potassium Chloride<br>Potassium Chloride (KCl) 6 mmol three times daily | Other: Potassium Chloride<br>* Active control<br>* Other names: PCl;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Submaximal Exercise Endurance | Time to exhaustion while exercising at 75% of peak workload | week 6 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Skeletal muscle oxidative capacity | MRI assessment of skeletal muscle oxidative phosphorylation capacity | week 6 | 
| Vasodilatory Reserve | Percent change in systemic vascular resistance at baseline vs exhaustion | week 6 | 
| Kansas City Cardiomyopathy Questionnaire Overall Summary Score | Assess the impact of our interventions on quality of life | week 6 | 
| VO2 Kinetics | Assess the impact of our interventions on the kinetics of oxygen consumption (VO2 kinetics) during exercise and recovery On and Off kinetics will be modeled during the submaximal exercise transient | week 6 | 
| Peak VO2 | maximal rate of oxygen consumption determined during the last 30s of exercise. | week 6 | 
| Steps per day | we will use actigraphy to document the average number of steps taken per day during the final week of each interventional period. Assess the impact of our interventions on ambulatory physical activity | week 6 | 
| Skeletal muscle perfusion | MRI assessment of skeletal muscle oxidative phosphorylation capacity | week 6 |