Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 21

Unstable angina is traditionally defined as any of the following clinical presentations, with or without ECG evidence of ischemia and with a normal troponin:

 Crescendo exertional angina: angina that increases in frequency, intensity, or duration, often requiring a more frequent use of nitroglycerin

 New-onset (< 2 months) severe exertional angina, occurring during normal activities performed at a normal pace

True resting angina of ACS will generally result in a troponin rise. In case of a serially negative troponin, and even more so, serially undetectable troponin (< 0.003–0.01 ng/ml), ACS is very unlikely, and the 30-day risk of coronary events is < 0.5%. ^28-30 In the current era of sensitive troponin, resting chest pain is generally either MI or non-cardiac pain (+/- vasospastic angina), not unstable angina.

Unstable angina and NSTEMI are grouped together as non-ST-segment elevation ACS (NSTE-ACS). However, it must be noted that unstable angina has a much better prognosis than NSTEMI, particularly that many patients labeled as unstable angina do not actually have true angina, and if they do, the underlying CAD is stable CAD, sometimes severe, but not ACS.^4,31 In fact, in the current era of highly sensitive troponin assays, a true ACS with coronary thrombosis or resting pain is accompanied by a troponin rise. Unstable angina is, thus, a vanishing entity. ³²

The patient either has non-cardiac pain, stable angina (sometimes severe), or true ACS with positive troponin. The negative troponin, truly “unstable angina” is rare and is more in the realm of severe or progressive stable angina than unstable CAD with plaque rupture.