Influence of Aortic Coarctation on Pulsatile Hemodynamics in the Proximal Aorta

Abstract

Pressure and flow were recorded in the ascending aorta of three dogs with aortic coarctation, induced surgically 3 months previously, and in three control litter mates. From these data were derived input impedance of the systemic circulation, pulsatile and steady components of external heart work, aortic systolic pressure-time index, and mean systolic and mean diastolic pressures. Results were correlated with intraoperative measurements of aortic pressure in three young patients with aortic coarctation and with records taken in another 24 patients during diagnostic catheterization. Distinctive changes in aortic impedance with coarctation were explained in terms of altered peripheral reflection. Such changes were responsible for characteristic alteration in central aortic pressure pulse contour and for change in other parameters, indicating impaired arterial function in accepting pulsatile flow from the heart. Such changes in the cushioning function appear responsible for many clinical features and complications of aortic coarctation. Surgery is probably justified for restoration of the normal cushioning function of the arterial system as well as for reduction of resistance and mean arterial pressure.