Korean J Thorac Cardiovasc Surg.  2000 Oct;33(10):777-784.

Alterations in Left ventricular End-systolic Wall Stress During Short-term Follow-up After Correction of Isolated Congenital Aortic Stenosis

• Kim SH
• Park YH
• Hong YS
• Kim DK
• Cho BK

Abstract

BACKGROUND: Congenital aortic stenosis in children is characterized by "excessive" left ventricular hypertrophy with reduced left ventricular systolic wall stress that allows for supernormal ejection performance. We hypothesized that left ventricular wall stress was decreased immediately after surgical correction of pure congenital aortic stenosis. Also measuring postoperative left ventricular wall stress was a useful noninvasive measurement that allowed direct assessment for oxygen consumption of myocardium than measuring the peak systolic pressure gradient between ascending aorta and left ventricle for the assessment of surgical results. MATERIAL AND METHOD: Between September 1993 and August 1999, 8 patients with isolated congenital aortic stenosis who underwent surgical correction at Yonsei cardiovascular center were evaluated. There were 6 male and 2 female patients ranging in age from 2 to 11 years(mean age, 10 years). Combined Hemodynamic-Ultrasonic method was used for studying left ventricular wall stress. We compared the wall stress peak systolic pressure gradient and ejection fraction preoperatively and postoperatively. RESULT: After surgical correction peak aortic gradient fell from 58.4+/-17.6, to 23.7+/-17.7 mmHg(p=0.018) and left ventricular ejection fraction decreased but it is not statistically significant. In the consideration of some factors that influence left ventricular end-systolic wall stress excluding one patient who underwent reoperation for restenosis of left ventricular outflow tract left ventricular end-systolic pressure and left ventricular end-systolic dimension were fell from 170.6+/-24.3 to 143.7+/-27.1 mmHg and from 1.78+/-0.4 to 1.76+/-0.4 cm respectively and left ventricular posterior wall thickness was increased from 1.10+/-0.2, to 1.27+/-0.3cm but it was not statistically singificant whereas left ventricular end-systolic wall stress fell from 79.2+/-24.9 to 57.1+/-27.6 kdynes/cm2(p=0.018) in 7 patients. For one patient who underwent reoperation peak aortic gradient fell from 83.0 to 59.7 mmHg whereas left ventricular end-systolic wall stress increased from 67.2 to 97.0 kdynes/cm2 The intervals did not change significnatly.
CONCLUSION
We believe that probably some factors that are related to left ventricular geometry influenced the decreased left ventricular wall stress immediately after surgical correction of isolated congenital aortic stenosis. Left ventricular wall stress is a noninvasive measurement and can allow for more direct assesment than measuring peak aortic gradient particularly in consideration of the stress and oxygen consumption of the myocardium therefore we can conclude it is a useful measurement for postoperative assessment of congenital aortic stenosis.

MeSH Terms

Aorta
Aortic Valve Stenosis*
Blood Pressure
Child
Equidae
Female
Follow-Up Studies*
Heart Ventricles
Humans
Hypertrophy, Left Ventricular
Male
Myocardium
Oxygen Consumption
Reoperation
Stroke Volume