Bypass Surgery for Prinzmetal Variant Angina

To the Editor.  —A recent article in the Archives recommending bypass surgery for Prinzmetal angina deserves some comment (Bentiviglio et al, 136:313-316, 1974). Though localized stenosis of the coronary arteries¹ is frequently demonstrated in variant as well as in classic angina, the additional occurrence of coronary artery spasm has been sometimes documented in variant angina pectoris.^2-4 Likewise, coronary artery spasm has been documented in patients with variant angina and angiographically normal coronary arteries.⁵ The hemodynamic changes occurring with variant angina appear to differ from those occurring with classic angina. Patients with classic angina commonly exhibit an increase in the pressure-time index prior to spontaneous or induced angina. In contrast, patients with variant angina frequently do not exhibit an increase in the pressure-time index; in fact, it often falls during pain. These findings suggest that, at least in some cases of variant angina, the pain may be