Two of our previous studies [1, 2] relate to Dr. Ruttimann and colleagues' interesting suggestion that smokers have a higher baseline renin value and an increased renin reactivity to captopril. First, we showed that smokers (also defined as persons who smoke 20 or more cigarettes per day) who are matched to nonsmokers for age, gender, and race had the same plasma renin activity values as nonsmokers [1]. In our recent second study, we showed that the bulk of false-positive captopril tests arise in patients whose baseline plasma renin activity value is elevated [2]. In contrast, among patients with normal and low renin activity values, specificity was 99%. In this study, only two of eight patients with a false-positive test result were smokers (unpublished data). Thus, we suggest that the exaggerated renin response leading to the false-positive captopril test results are related to the elevation of baseline renin rather than to smoking status.

We agree with Dr. Martinez about defining before workup the risk of a revascularization procedure and the willingness of the patient to have such invasive procedures. Fortunately, in the patient without complications, the risk of surgical revascularization is much lower than Dr. Martinez cites. Even in patients with advanced atheromatous disease, surgical revascularization should have a lower mortality than the 20-year-old Figure of9.3% given by Dr. Martinez, and the procedure has the additional benefit of improving renal function [3]. In addition, balloon angioplasty is an option, but its feasibility often cannot be ascertained until the arteriogram is done and the anatomy is apparent.

Dr. Martinez correctly notes that some patients can be managed medically without exposure to the risk of surgery or angioplasty. Although minoxidil is a potent drug, the side effect of sodium retention makes it difficult to use. The dihydropyridine dose of calcium channel blockers may be a preferable alternative.