Aortic Stenosis and PhosphodiEsterase Type 5 iNhibition (ASPEN): A Pilot Study

The Washington University

Status and phase

Terminated

Phase 4

Conditions

LV Remodeling, Hypertrophy

Aortic Stenosis

Treatments

Drug: Placebo

Drug: Tadalafil

Study type

Interventional

Funder types

Other

Identifiers

NCT01275339

10-1334b

Details and patient eligibility

About

Currently, aortic stenosis (AS) is considered a "surgical disease" with no medical therapy available to improve any clinical outcomes, including symptoms, time to surgery, or long-term survival. Thus far, randomized studies involving statins have not been promising with respect to slowing progressive valve stenosis. Beyond the valve, two common consequences of aortic stenosis are hypertrophic remodeling of the left ventricle (LV) and pulmonary venous hypertension; each of these has been associated with worse heart failure symptoms, increased operative mortality, and worse long-term outcomes. Whether altering LV structural abnormalities, improving LV function, and/or reducing pulmonary artery pressures with medical therapy would improve clinical outcomes in patients with AS has not been tested. Animal models of pressure overload have demonstrated that phosphodiesterase type 5 (PDE5) inhibition influences nitric oxide (NO) - cyclic guanosine monophosphate (cGMP) signaling in the LV and favorably impacts LV structure and function, but this has not been tested in humans with AS. Studies in humans with left-sided heart failure and pulmonary venous hypertension have shown that PDE5 inhibition improves functional capacity and quality of life, but patients with AS were not included in those studies. The investigators hypothesize that PDE5 inhibition with tadalafil will have a favorable impact on LV structure and function as well as pulmonary artery pressures. In this pilot study, the investigators anticipate that short-term administration of tadalafil to patients with AS will be safe and well-tolerated.

Full description

Subjects with moderately severe to severe aortic stenosis (AS), left ventricular hypertrophy (LVH), diastolic dysfunction, preserved ejection fraction, and no planned aortic valve replacement over the next 6 months will be eligible for this randomized, double-blind, placebo-controlled, pilot study. There will be a diabetic cohort (n=32) and non-diabetic cohort (n=24); each cohort will be randomized 1:1 to tadalafil vs. placebo. During a baseline study visit, the following will be obtained: clinical data, 6 minute walk, quality of life questionnaire, blood draw, and an echocardiogram. A 3-day run-in will occur to initially assess tolerability and compliance. If the drug is tolerated during this run-in period, participants will be randomized. An MRI will also be performed during this randomization visit. Follow-up study visits and testing will occur at 6 and 12 weeks and 6 months.

Enrollment

10 patients

Sex

All

Ages

18+ years old

Volunteers

No Healthy Volunteers

Inclusion criteria

Patients with moderate to severe aortic stenosis (AVA < 1.5 cm2)
Left ventricular hypertrophy
Diastolic dysfunction as evidenced by tissue Doppler e' (average of septal and lateral) ≤ 7 cm/s
EF ≥ 50%
None or minimal symptoms related to aortic stenosis (NYHA ≤ 2)
The subject and treating physician are not planning on a valve replacement procedure to occur during the next 6 months
Ambulatory
Normal sinus rhythm
18 years of age and older
Able and willing to comply with all the requirements for the study

Exclusion criteria

Need for ongoing nitrate medications
SBP < 110mmHg or MAP < 75mmHg
Moderately severe or severe mitral regurgitation
Moderately severe or severe aortic regurgitation
Contraindication to MRI
Creatinine clearance < 30 mL/min
Cirrhosis
Pulmonary fibrosis
Increased risk of priapism
Retinal or optic nerve problems or unexplained visual disturbance
If a subject requires ongoing use of an alpha antagonist typically used for benign prostatic hyperplasia (BPH) (prazosin, terazosin, doxazosin, or tamsulosin), SBP < 120 mmHg or MAP < 80 mmHg is excluded
Need for ongoing use of a potent CYP3A inhibitor or inducer (ritonavir, ketoconazole, itraconazole, rifampin)
Current or recent (≤ 30 days) acute coronary syndrome
O2 sat < 90% on room air
Females that are pregnant or believe they may be pregnant
Any condition which the PI determines will place the subject at increased risk or is likely to yield unreliable data
Unwilling to provide informed consent