Effect of different antihypertensive drug classes on central aortic pressure

Central aortic systolic blood pressure (BP) is an important determinant of cardiac workload and cardiac hypertrophy. The relationship of central aortic systolic BP and brachial BP varies depending on the stiffness of blood vessels. It is not certain whether the different drug classes affect the brachial and aortic systolic BP in a similar manner. In a double-blind crossover study, we measured the effects of the four major drug classes compared with placebo on central aortic pressure. Central aortic pressure and various indices were determined using the Sphygmo Cor apparatus. The study was undertaken in patients aged 65 to 85 years with systolic BP >150 mm Hg at study entry. Results are reported for 32 patients who had satisfactory applanation tonometry in all five periods. Calcium channel blockers and diuretics caused a greater fall in brachial artery systolic BP than angiotensin-converting enzyme (ACE) inhibitors or beta-blocking drugs. On placebo, central aorta augmentation pressure and index were 23 mm Hg and 33.3%; on ACE inhibitors the values were 18 mm Hg and 30%; on beta-blockers, 26 mm Hg and 38.5%; on calcium channel blockers, 16 mm Hg and 28%; and on diuretics, 17 mm Hg and 28.8%. The augmentation pressure on beta-blocking drugs was greater than on the other three drug classes (P <.05), and augmentation pressures on ACE inhibitors, calcium channel blockers, and diuretics were less than on placebo (P <.05). The lowest central aortic pressures were achieved with calcium blocking drugs and diuretics. Therapy based on brachial artery recordings may thus overestimate the effect of beta-blocking drugs on central aortic systolic BP and underestimate the effectiveness of ACE inhibitors and calcium blocking drugs. The clinical importance of this discrepancy needs to be evaluated.