In year 1959 Prinzmetal et al reported 32 patients of angina which occurred at rest unlike William Heberden classical angina which was associated with exertion
Clinical
characteristics of Prinzmetal angina are.
Exertion did not precipitate angina and stress tests was typically negative in these
patients
ST elevation was noted during pain as opposite to classical
angina where ST depression is present.
Angina occurred during same time of the day.
These angina episodes sometimes associated with
arrhythmias
and sometimes progressed to MI.
The basic pathology of Variant angina is spasm of
epicardial coronary arteries.
Clinical
features
These patients classical have chest pain which
occurs at rest at a same time of day more commonly early morning hours,
transient ST changes, relived promptly by nitrates
As these patients are prone for arrhythmias they may
also present with syncope and cardiac arrest.
Among conventional risk factors for atherosclerosis
only cigarette smoking is associated with Prinzmetal angina.
Waxing and waning, circadian nature of chest pain
should make clinician to consider about this disease. Episode of Prinzmetal
angina may come in clusters.
Diagnostic
tests
Ambulatory ECG monitoring :As
ECG changes are transient to pick ECG changes, ambulatory ECG monitoring is done
during hot phases i.e. when cluster of chest recur.
Exercise stress
is negative
Coronary angiography:
Normal coronaries are not mandatory for Prinzmetal angina diagnosis. Spasm of insignificant epicardial disease
with ST elevation also produce Prinzmetal angina.
Provocative coronary
artery test
·
Acetylcholine
o
Intracoronary acetylcholine is
administered in incremental doses temporary pacing is needed frequently to overcome
acetylcholine induced bradycardia. For RCA incremental doses of 25-50micrograms
and LCA incremental boluses of 25-100micrograms are given
·
Ergonovine
o
Some use 60micrograms of intracoronary Ergonovine slowly either into RCA
or LCA
o
Others give intracoronary Ergonovine every
5 minutes in incremental fashion i.e.
30-300micrigrams
·
Reporting
o
Test is considered positive if inducible
coronary spasm is presence, assessed on
the basis of chest pain, ECG changes and/or severe coronary constriction.
Differential
diagnosis
STEMI: Prompt response
to nitrates suggest variant angina
Mixed pattern angina:
In this both exercise and rest angina are present due obstructive coronary
artery disease and also spasm of coronary artery disease respectively
Tako-tsubo
cardiomyopathy: this also can
present with transient ST changes at rest. Differencatation will be by apical ballooning
of Tako-tsubo cardiomyopathy. Some people speculate Tako-tsubo cardiomyopathy
is also due to spasm of epicardial vessels
Coronary microvascular disorders: Normal epicardial vessel with rest angina,
suggest variant angina or microvascular disease, this can be differentiated demonstration
epicardial spasm of epicardial vessels in variant angina.
Diagnostic
criteria
Clinical criteria
o
With Rest angina transient ST elevation
and improvement or resolution symptoms with sublingual nitrates.
Angiographic criteria
o
Rest angina.
o
Reversible ST changes (elevation or
depression), and/or
o
Spontaneous/provoked coronary spasm on
angiography. (90% sensitivity and 99% specificity in the provoked spasm on
angiography)
Treatment
1. Stop
smoking
2. Short
acting nitrates
3. Calcium
channel blockers
4. Potassium
channel openers, nicorandil
5. Rho
kinase inhibitor, fasudil
Prognosis
1. Significant
morbidity and mortality 5year infract free survival is 60-95%
2. Calcium
channel blockers and associated coronary obstructive and multi vessel disease
also effect infarct free interval.
3. Caucasian
have poorer outcomes than their Japanese counterparts, which in part may be due
to the increased prevalence of coronary artery disease.
