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November 18, 2005
By
Jennifer Tartaglia M.S. and Asher Kimchi M.D.
Los Angeles, CA -
There are several clinical variables that are used to evaluate
prognosis in known or suspected coronary artery disease
patients. Dyspnea is a common symptom that may indicate
subclinical left ventricular dysfunction or pulmonary disorders,
and may be equivalent to the symptom of exertional angina. Aiden
Abidov, M.D., Ph.D., et al. from Cedars-Sinai Medical Center in
Los Angeles, CA studied the incremental prognostic value of
symptom categories in predicting the risk of death in patients
who underwent myocardial-perfusion single-photon-emission
computed tomography (SPECT) during stress and at rest. Their
study, published in the November 3, 2005 issue of The New
England Journal of Medicine shows that in a large cohort of
patients, those who self-reported dyspnea, identified a subgroup
of asymptomatic patients who were at an increased risk of death
from cardiac and noncardiac causes.
Though dyspnea,
fatigue, and palpitations are somatic symptoms that may be
associated with coronary artery disease, there have been limited
studies predicting the risk of cardiac events in patients having
these symptoms. In this study Abidov et al evaluated consecutive
patients with no known cardiomyopathy or valvular disease who
were subjected to myocardial-perfusion SPECT with
exercise-induced stress or vasodilator-induced stress. Patients
were divided into five groups based on their self-reported
symptoms of chest pain and dyspnea at the time of testing
(asymptomatic, nonanginal chest pain, atypical angina, typical
angina, and dyspnea). All patients were prospectively enrolled
in a registry, and follow-up data was collected for a minimum of
one year after testing.
Of 17,991
patients who had myocardial-perfusion SPECT, 11,888 (66.1%) had
exercise-induced stress and 6103 (33.9%) had vasodilator-induced
stress. During the follow-up time (mean ± SD = 2.7 ±1.7 years),
786 patients without known coronary artery disease died, 224 of
cardiac causes; and 720 patients with apparent coronary artery
disease died, 347 of cardiac causes. Dyspnea seemed to be an
independent and incremental predictor of death on multivariable
analysis, since the hazard ratios for death from cardiac causes
in patients with dyspnea with and without known coronary artery
disease were 1.9 (95 percent confidence interval, 1.5 to 2.4)
and 2.9 (95 percent confidence interval, 1.7-5.1) respectively.
There was a substantially higher risk of death from cardiac and
non-cardiac causes in patients with dyspnea than in those with
other or no symptoms (P<0.001). Myocardial-perfusion SPECT of
the study participants found that there was a higher rate of
left ventricular enlargement in patients with dyspnea than the
other four categories of patients. Patients with dyspnea also
had higher rates of atrial fibrillation and left ventricular
hypertrophy on electrocardiography (P<0.05).
The results of
the study indicate that increased rates of death from cardiac
causes and death from any cause exist in patients with dyspnea,
both with and without known coronary artery disease. Among
patients without known coronary artery disease, patients with
dyspnea had four times the risk of death from cardiac causes
than asymptomatic patients and at least twice the risk of
patients with typical angina. Consequently, the authors of this
study suggest that it may be beneficial to include an evaluation
of dyspnea in the clinical assessment of patients referred for
cardiac stress testing and in the algorithms used to assess
prognosis of coronary artery disease.
Co-authors: Alan
Rozanski, M.D., Rory Hachamovitch, M.D., Sean W. Hayes, M.D.,
Fatma Aboul-Enein, M.D., Ishac Cohen, Ph.D., John D. Friedman,
M.D., Guido Germano, Ph.D., and Daniel S. Berman, M.D. | 
