We therefore must rely on clinical studies with surrogate end points and the few relevant clinical trials with outcomes data to attempt to resolve this issue. 3.2. Clinical Studies 3.2.1. Lower BP With a Surrogate Outcome An analysis of the 274 patients with CAD who completed the intravascular ultrasound substudy of the Comparison of AmlodipineVersusEnalapriltoLimitOccurrencesofThrombosis showed that those subjects with a normal BP according to the definition given in the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure3 (<120/80 mmHg) had a mean decrease in coronary atheroma volume of 4.6 mm3 , pre- hypertensive (120 139/80 89 mmHg) subjects had no signifi- cant change, and hypertensive ( 140/90 mmHg) subjects had a mean increase in atheroma volume of 12.0 mm3 . The authors concluded, This study suggests that in patients with CAD, the optimal BP goal may be substantially lower than the <140/90 mmHg level. The results of CAMELOT can be taken only as hypothesis generating because the effect of achieved BP on ath- eroma volume was not a prespecified outcome. Because this was a post-hoc analysis, there is the potential for residual confound- ing effects, especially because the individuals in the higher BP cohort were older and were more likely to have been assigned to the placebo arm of the study and therefore not treated with either amlodipine or enalapril. 3.2.2. Observational Studies and Clinical Trials If coronary autoregulation were clinically important, it would be predicted that a U-shaped or J-shaped relationship should exist between DBP and CAD events. Furthermore, the pres- ence of structural CAD could be expected to affect the pres- sure-flow relationships in the coronary arteries, with a lower tolerance of diastolic pressures. 