The aortic wrap procedure: a surgical method of treating agerelated aortic dilatation and stiffening.

Abstract

Introduction: There is progressive stiffening and dilatation of the aorta and large elastic arteries with aging as a result of the repetitive cyclic stress they are exposed to throughout life. Aortic stiffening has a number of detrimental effects including an increase in aortic pulse wave velocity and early wave reflection, isolated systolic hypertension, ventricular-vascular mismatch, impaired coronary blood flow reserve, and is thefundamental cause of heart failure in the elderly. The aim of this thesis is to provide proof of concept forthe aortic wrap procedure; a surgical treatment of stiffening and dilatation of the ascending aorta withaging. The surgical procedure involves wrapping an elastic material around the ascending aorta of elderlypatients, to reduce the stiffness and diameter of the ascending aorta towards that seen in youth.Methods: Proof of concept is investigated in the following studies. 1. The effect of the elastic wrap on thein-vivo stiffness of the normal aorta. 2. The effect of the elastic wrap on the in-vivo stiffness of the dilatedand stiffened aorta. 3. The effect of the elastic wrap on the in-vitro stiffness of the aged human ascendingaorta and on aortic pressure. 4. The effect of wrapping the aged human ascending aorta on pulsepressure (mathematical model). 5. The effect of chronic implantation on the structure of the normal aorta.6. The mechanical properties of the ovine thoracic aorta and the elastic wrap material.Results: 1. Elastic wrap application increased the in-vivo stiffness of the normal aorta. 2. Elastic wrapapplication decreased the stiffness of the stiffened and dilated aorta. 3. Elastic wrap application decreasedthe in-vitro stiffness of the elderly human ascending aorta and pulse pressure. 4. A reduction in ascendingaortic stiffness was sufficient to reduce ascending aortic pulse pressure.Conclusion: Application of the elastic wrap to the aged human ascending aorta is expected to reduceaortic stiffness, as well as systolic and pulse pressure, and to increase diastolic pressure with a reductionin cardiac load. The aortic wrap procedure may be an effective surgical procedure for the treatment ofheart failure and isolated systolic hypertension