RELATIONSHIP BETWEEN END-SYSTOLIC AORTIC PRESSURE AND MEAN AORTIC PRESSURE IN ADULTS

The mean blood pressure is an accurate estimate of the end-systolic ao rtic pressure in children. The aim of this study was: 1) to assess the relationship between the pressure at the incisura (PIAo) and the mean (MAoP) and pulse (PAoP) pressures of the supravalvular aorta in adult s; and 2) to evaluate MAoP as an estimate of PIAo in adults. High fide lity pressure recordings were carried out in the supravalvular aorta i n 17 men. The pressures were measured at rest in 10 consecutive beats and, in 6 subjects, during a Valsalva manoeuvre. At rest, PIAo was gre ater than the MAoP (109 +/- 17.9 versus 99.6 +/- 12.5 mmHg, p = 0.0001 ). There was a positive linear correlation between PIAo and MAoP (r = 0.93) and between PIAo and PAoP (r' = 0.77) whereas no correlation was observed between PIAo and heart rate, cardiac output or estimated tot al systemic arterial compliance. A beat-to-beat relationship was obser ved between PIAo and MAOP : 1) at rest in 16 of the 17 subjects and 2) in each subject who performed a Valsalva manoeuvre. Both at rest and during Valsalva, MAOP underestimated PIAo significantly, especially wh en PIAo was increased (p = 0.0001). The authors conclude that end-syst olic supraaortic pressure is mainly related to the mean component of a ortic pressure. MAOP slightly but constantly underestimated PIAo and t his should lead to caution in assimilating MAOP to end-systolic aortic pressure in adults, especially in subjects with very high aortic pres sures.