Measuring Blood Pressure: Which Arm?-Reply

In Reply. —Dr Panayiotou's group notes that BP inequality between arms can be clinically important and suggests a prevalence of 23%. 1 Studies earlier in this century using non-simultaneous readings reported interarm differences of greater than 10 mm Hg systolic in about 20% to 50% of patients, whereas simultaneous readings suggested a markedly lower prevalence, 2.6% to 17%. 2 In their article 1 Panayiotou's group cites Harrison et al, 2 whose single, immediately sequential noninvasive readings suggested that 26.6% of 454 subjects had such a difference; however, when two observers obtained three simultaneous readings (same heartbeats, cuffs connected by a T tube), only 5.3% of subjects showed this degree of discrepancy. 2 Adding invasive measurements approximately halved the prevalence, and just one patient showed a consistent difference. More recently, Hashimoto et al 3 also observed 28% to have a difference in systolic BP of greater than 8 mm Hg. However,