New Blood Tests
Unique Identifier 20192727
Author Cassin M; Badano LP; Solinas L; Macor F; Burelli C; Antonini-Canterin
F; Cappelletti P; Rubin D; Tropeano P; Deganuto L; Nicolosi GL
Institution Unita Operativa di Cardiologia-ARC, Azienda Ospedaliera
S. Maria degli Angeli Pordenone. mat54@iol.it.
Title [Is a more efficient operative strategy feasible for the
emergency management of the patient with acute chest pain?]
Vernacular Title [E realizzabile una strategia operativa piu efficace
per la gestione in urgenza del paziente con dolore toracico acuto?]
Source Ital Heart J 2000 Feb;1(2 Suppl): p186-201
ISSN 1129-471X
Abstract
Patients with acute chest pain are a common problem and a difficult challenge
for clinicians. In the United States more than 5 million patients are
examined in the emergency department on a yearly basis, at a cost of
6 billion dollars. In the CHEPER registry the prevalence of patients
with chest pain in the Emergency Department was 5.3%. Similarly, in
1997 at our institution the prevalence was 4.8%. Only 50% of the patients
are subsequently found to have cardiac ischemia as the cause of their
symptoms and 50-60% of them showed a non-diagnostic electrocardiogram
(ECG). Twenty-five-50% of chest pain patients are not appropriately
admitted to the hospital and despite this conservative approach, acute
myocardial infarction is misdiagnosed up to 8% of patients with acute
chest pain who are released from the emergency department without further
evaluation, accounting for approximately 20% of emergency department
malpractice in the United States. Important diagnostic information is
covered by the patient's medical history, physical examination, and
ECG, but often this approach is inadequate for a definitive diagnosis.
Creatine kinase (CK) and CK isoenzyme--cardiac muscle subunit (CK-MB)--are
traditionally obtained in the emergency department in patients admitted
for suspected acute coronary syndrome. Mass measurements of CK-MB have
improved sensitivity and specificity, and to date this is the gold standard
test for diagnosis of acute myocardial infarction. CK-MB, however, is
not a perfect marker because it is not totally cardiac specific and
does not identify patients with unstable angina and minimal myocardial
damage. There are no controlled clinical impact trials showing that
these tests are effective in deciding whether to discharge or to appropriately
admit the patient with suspected acute coronary syndrome. Relevant investigative
interest has recently been focused on new markers for myocardial injury,
including myoglobin, cardiac troponins T and I. Myoglobin, a sensitive
but not specific marker for cardiac damage, increases earlier than CK-MB
and cardiac troponins. It should be used early after symptom onset and
in conjunction with a more specific marker of myocardial damage. Cardiac
troponins T and I are highly specific markers for cardiac damage, rise
parallel to CK-MB and remain elevated longer, up to 5 to 9 days. They
are useful for detection of less severe degrees of myocardial injury,
which may occur in several patients with unstable angina who are at
higher risk of cardiac events. Recent studies suggest that cardiac troponins
have good diagnostic performance and prognostic value in the heterogeneous
population of patients seen in the Emergency Department with acute chest
pain. Despite these promising data, several analytical and interpretative
problems in the routine use of cardiac troponins must be solved. Incremental
value of echocardiography in acute chest pain patients is still uncertain.
Echocardiography can be recommended as an adjunctive test if readily
available during acute chest pain or prolonged pain, especially in patients
without previous myocardial infarction. Rest myocardial radionuclide
imaging has been studied in the emergency department setting and although
the overall diagnostic performance and prognostic value of sestamibi
has been found to be promising, it is not suitable, in our country,
for extensive clinical use. ECG exercise stress test in the emergency
department population has been shown to be safe and it has a good negative
predictive value for cardiac events. It should be recommended that any
institution identify specific and shared protocol and strategies for
management of patients with chest pain. These should include basal clinical
evaluation, serial ECG and the use of specific and sensitive myocardial
markers. Adjunctive tests, such as echocardiography, nuclear studies
and stress tests should be employed when indicated taking into account
local facilities.
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