Chest Pain Perception and Capsaicin Sensitivity in Patients With Acute Cardiac Ischemia

Chest discomfort is considered the hallmark of myocardial ischemia and as such is an
important clinical warning sign of myocardial infarction (MI). The ability to sense ischemic
chest discomfort appears to be impaired in a substantial minority of the population and such
individuals are presumably at increased risk for unrecognized MI. While the mechanism(s)
responsible for the perception of chest pain associated with myocardial ischemia are still
not fully understood, studies suggest that the transient receptor potential vanilloid-1
(TRPV1) plays a key role in this process. This nociceptor, which is known to mediate pain
sensation in the skin and elsewhere in the peripheral nervous system, has also been found on
the outer surface of the heart and has been shown to respond to ischemic stress in this
organ.

The purpose of this study is to determine whether there is a positive correlation between
the ability to sense chest pain in the context of myocardial ischemia and the ability to
sense discomfort associated with the topical application of the TRPV1 agonist capsaicin (the
active ingredient on hot chili peppers). Patients undergoing urgent or emergent balloon
angioplasty of an acute coronary stenosis will be asked to quantify the subjective intensity
of any chest pain they feel during a standardized episode of myocardial ischemia produced by
a one-minute coronary balloon occlusion, using a previously-validated numeric rating scale.
The same patients will subsequently be asked to grade the subjective intensity of cutaneous
discomfort resulting from application of a capsaicin-containing patch (Capzasin-HP Cream, an
over-the-counter product approved for topical application to treat muscle and joint aches)
to the forearm. The goal will be to determine whether an association can be demonstrated
between the subjective perception of ischemic chest pain during coronary balloon occlusion
and cutaneous capsaicin sensitivity. Such an association could have considerable clinical
value, as it might allow physicians to prospectively assess an individual's ability to
perceive myocardial ischemia/infarction by assessing his/her subjective response to the
topical application of capsaicin. This study is designed to be a companion project to
Project 1029 Chest Pain Perception and Capsaicin Sensitivity, which is collecting the same
data from clinically stable patients undergoing elective cardiac catheterization.

Inclusion Criteria:

Subjects will consist of patients who have undergone clinically-indicated PCI for the
treatment of coronary artery disease. This study will include clinically unstable
patients, such as those undergoing emergency percutaneous coronary intervention (PCI) for
acute myocardial infarction, etc.

Exclusion Criteria:

Patients with documented hypersensitivity to capsaicin will be excluded and patients who
have used a capsaicin-based product within the last 3 months will be excluded