Functional vascular tissue engineering aims to produce blood vessels in vitro in a controlled environment named bioreactor. In order to control the growth and remodeling of vascular tissues, suitable measurements should be made on the construct in situ, i.e. during the growth. These measurements will feed the controller with information in order to take efficient control decisions. The non-destructive measurement of compliance or elastic modulus in vitro is a potential indicator of the vascular construct maturity. This work shows that compliance and elastic modulus are related: they can be estimated during the growth of constructs in a bioreactor, and thus provide useful feedback information to the controller.