Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 225

An underlying significant CAD is treated with PCI or CABG as appropriate. Beware that, sometimes, the lesion is only moderate and not hemodynamically significant, but becomes significant when vasospasm aggravates it; in those cases, revascularization is not indicated and good results are obtained with CCBs.

In the absence of severe CAD, CCBs are first-line therapy. CCBs are very effective (control of symptoms in 83% of patients),¹²³ and spontaneous remission is also very common.^116-118 Nitrates may also be used, but are less effective (31%).¹²³ β-Blockers may exaggerate vasospasm through blocking the β₂-receptor, but may be beneficial in patients with a fixed stenosis and exertional symptoms. In comparison with CCB monotherapy, the combination of CCB and statin has been shown to dramatically reduce vasospasm in one trial.¹²⁴

The long-term risk of cardiac events is intermediate and is partly related to the extent of underlying CAD.^4,5 In five series, patients without CAD had a lower, but still significant, risk of MI (up to 15%),^{5,115,118,119,123} VT (25%),^5,118,123 syncope from arrhythmia (20%), and particularly cardiac arrest (2.5%)^115,119 at several years of follow-up; these patients, for the most part, were not receiving CCB. In fact, vasospasm has been well documented as a cause of cardiac arrest in five patients without significant CAD; CCB prevented ergonovine-induced spasm and arrhythmias in these patients.¹²⁵ The severity of vasospasm, as evidenced by the severity and extent of ST elevation, correlates with adverse events and ventricular arrhythmias regardless of the underlying CAD.^115,119 Similarly, prior MI or cardiac arrest are strong predictors of future events.¹¹⁹

Patients receiving CCBs have a much more benign course with much less angina, much less unstable angina (6% at 3 years), and 10× lower risk of MI and cardiac death (<3% at 3 years), which suggests the great efficacy of CCBs.^{115,117,119,122} However, in patients who have already had a cardiac arrest, CCB therapy does not fully eliminate the risk of VF, and ICD may be justified (in one series, 15% of patients receiving ICD had appropriate shocks despite CCB therapy; in another series, > 50% had VT/VF or ICD shock despite CCB therapy).^119,126 Abstinence from smoking and alcohol is also associated with a reduction of events.