Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 184

It was initially hypothesized by Prinzmetal and then demonstrated in an old series that vasospasm and vasospastic angina often occur at the site of a significant atherosclerotic obstruction in patients with significant CAD.^4,5. CAD was not only significant but frequently unstable.⁵ Later reports suggest that vasospasm is also a common diagnosis in patients with angina and no significant CAD, men or women.⁶ Even in patients with normal or near-normal coronary arteries, atherosclerosis is documented at the site of vasospasm, and, in fact, vasospasm correlates with the atherosclerotic burden at this site.^7,8 Vasospasm may be related to vasoconstrictors released by platelets and leukocytes at the atherosclerotic site, or endothelial dysfunction and abnormal vasomotor response induced by atherosclerosis.⁷ Paradoxical vasoconstriction may occur during exercise, adrenergic stimulation (stress), or cold exposure. Approximately 60% of patients only have symptoms at rest or mild activity without exertional limitation, sometimes in a cyclic nocturnal pattern; in those patients, angina only occurs when the dynamic component exacerbates the fixed obstruction.⁵ On the other hand, many patients have exertional angina, whether from the CAD itself or from the exertional vasospasm, and some patients only have exertional angina.⁶ Vasospastic angina is classically more severe than fixed-threshold angina, as the episodic obstruction is totally or subtotally occlusive, with more frequent arrhythmia, high-grade AV block, or syncope during the episodes. While characteristically more common in women, some series suggest that vasospasm is as common in men.^9,10