Isolated elevation of diastolic blood pressure. Real or artifactual?

Not infrequently, blood pressure measurement by the standard auscultatory technique yields a normal systolic pressure with an elevated diastolic pressure. The relatively narrow pulse pressure of such a measurement raises concern about the accuracy of the blood pressure measurement. The purpose of this study was to assess the accuracy of auscultatory blood pressure measurements in patients with an uncommonly narrow pulse pressure, particularly patients with an elevated diastolic but normal systolic pressure. Auscultatory blood pressure measurements were compared with an objective noninvasive standard, called K2 analysis, which has been shown to be more accurate than the auscultatory technique. Blood pressure was measured simultaneously by auscultatory and K2 techniques in 175 subjects. Comparisons were performed (1) in the group as a whole, (2) in four clinical subgroups (normotensive [< 140/< 90 mm Hg, n = 69], hypertensive [> or = 140/> or = 90 mm Hg, n = 53], isolated systolic hypertensive [> or = 140/< 90 mm Hg, n = 38], and isolated diastolic hypertensive [< 140/> or = 90 mm Hg, n = 15]), and (3) in two subgroups whose ratio of pulse pressure to diastolic pressure was greater than or equal to 0.45 (n = 151) or less than 0.45 (n = 24). Subjects in the isolated diastolic hypertensive group and in the group with a pulse pressure ratio less than 0.45 were considered to have a narrow pulse pressure. In the group as a whole, consistent with previous auscultatory-K2 comparisons, systolic pressure was slightly higher and diastolic pressure slightly lower when measured by K2 versus the auscultatory technique (auscultatory, 145/85 mm Hg; K2, 147/83 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)