Contribution of systemic vascular resistance and total arterial compliance to effective arterial elastance in humans

Publisher Website
Google Scholar
Abstract
The respective contribution of systemic vascular resistance ( R ) and total arterial compliance ( C ) to the arterial load remains to be established in humans. Effective arterial elastance ( E a), i.e., the left ventricular end-systolic pressure (LVESP)-over-stroke volume ratio, is a reliable estimate of arterial load. It is widely accepted that E a mainly relates to mean aortic pressure (MAP) and thus to the R -to- T ratio ( R / T ratio), where T is cycle length. We tested the contribution of R / T and 1/ C to E a in 20 normotensive and 46 hypertensive subjects (MAP range: 84–160 mmHg). The multilinear model applied ( E a = 1.00 R / T + 0.42/ C – 0.04; r 2 = 0.97). The sensitivity of E a to a change in R / T was 2.5 times higher than to a similar change in 1/ C in both normotensive and hypertensive adults. The LVESP was more strongly related to systolic aortic pressure (SAP; r 2 = 0.94) than to MAP ( r 2 = 0.83), and LVESP matched 90% SAP (bias = 0 ± 5mmHg). An alternative model of E a is proposed, in which E a is proportional to the heart rate × SAP product-over-cardiac index ratio whatever the MAP.