[The 19mm St. Jude Medical prosthetic aortic valve evaluated by long-term hemodynamic sequelae]. 
To assess the usefulness of the 19 mm St. Jude Medical (SJM) aortic valve prosthesis for cases of small aortic annulus, post-operative evaluations of pressure gradient of the prosthesis (AVR) and left ventricular (LV) function were performed using bicycle ergometric exercise tests.  Seven patients who underwent AVR with 19 mm SJM (19 mm group) and eight control subjects whose SJM was greater than 21 mm in diameter were observed.  LV function was assessed by the M-mode echocardiography and the pressure gradients of the prosthesis by the continuous wave Doppler echocardiography.  The results were as follows: 1.  Mean body surface area (BSA) was 1.35 m2 in the 19 mm group and 1.52 m2 in the control group (p less than 0.01).  2.  NYHA functional classes improved equally in both groups after surgery.  3.  The post-operative cardiac index at rest measured by cardiac catheterization significantly improved in both groups after surgery.  4.  Results of the exercise tests: 1) Left ventricular end-systolic volume index (LVESVI) was decreased on exercise in both groups: from 21.3 to 18.0 ml/m2 in the 19 mm group (p less than 0.01) and from 21.5 to 17.0 ml/m2 in the control group (p less than 0.01).  2) Ejection fraction and fractional shortening significantly increased in both groups on exercise.  3) The pressure gradients significantly increased on exercise in both groups: from 30.4 to 38.3 mmHg in 19 mm group (p less than 0.01) and from 28.8 to 36.6 mmHg in the control group (p less than 0.01).  Although the pressure gradients were greater in the 19 mm group, there were no significant differences between the two groups at rest and on exercise.  It was concluded that the 19 mm SJM aortic valve prosthesis was acceptable in size for small aortic annulus in elderly women whose body surface area was less than 1.47 m2.