Value of treadmill exercise test in pre‐ and postoperative children with valvular aortic stenosis

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Abstract
To determine the utility of graded treadmill exerise test (ETT) in estimating severity of obstruction in postoperative patients with aortic stenosis, we compared results to a nonoperated aortic stenosis group. Cardiac catheterization was performed in all patients. The interval between surgery and ETT in the postoperative group was 7.5 years (range 1.1–12.9). Mean and range values for postoperative versus nonoperative aortic stenosis groups respectively were: age 14.5 (7.9–20.8) versus 12.5 years (5.9–19.7); peak left ventricular pressure 150 (101–190) versus 144 mmHg (100–183); peak systolic ejection gradient (PSEG) 41 (15–75) versus 38 mmHg (14–80); left ventricular end‐diastolic pressure (LVEDP) 13.4 (7–20) versus 13.5 mmHg (8–20); and cardiac index 3.7 (2.4–5.6) versus 3.8 liters/min/m2 (2.6–4.9) (p for each = NS). ETT in the nonoperated patients correctly identified all those with PSEG ≥ 50 mmHg (sensitivity 100%), but specificity was 56%, (i.e., the proportion correctly identified with PSEG <50 mmHg). By contrast, sensitivity and specificity for postoperative aortic stenosis patients were 67% and 63%, respectively. Furthermore, among nonoperated aortic stenosis patients ST depression on ETT identified those with increased left ventricular end‐diastolic pressure. For LVEDP ≥ 12 mmHg, sensitivity was 75% and specificity 100%; corresponding values for postoperative aortic stenosis patients were 45% and 33%, respectively. In the nonoperated aortic stenosis group with a PSEG ≥50 mmHg, sensitivity and specificity for ETT‐induced change in systolic blood pressure of ≤30 mmHg were 100% and 56%, respectively. The data suggest that in patients with valvar aortic stenosis, ETT‐induced ST depression and systolic blood pressure change ≤30 mmHg are excellent indicators of obstruction (PSEG ≥50 mmHg) or diminished compliance (LVEDP ≥12 mmHg) in the nonoperated state but less sensitive indicators of severity in the postoperative state.