In our clinic for a period of 11 years, 1545 patients were operated upon for aortic valve diseases. Of these patients 9 (5.11 %) were found to have small aortic annulus for which an enlargement procedure was indicated. 36 patients of them entered into this study, 26 females 10 males. With a mean age of 37.45 (18-75) years.

The surgical procedures were indicated for those with an annular diameter of less than 21 mm performing the Nicks or Manouguian as a procedure of choice. During the enlargement procedure a concommitant intervention was done in 18 patients for a mitral valve procedure, l patient coronary artery bypass procedure, 2 patients septal myectomy and l patient subaortic valve membrane resection. In this studied group of patients a further intervention was found to be indicated in 8 patients in two or three occasions later.

Of the 79 aortic annulus enlargement cases, 53 patients underwent a Nicks procedure, where as 26 patients underwent Manouguian procedure. From these patients 26 from the first group and 10 patients from the 2nd group entered into this study respectivelly.

The late outcome of these 36 patients was compared with another 16 patients with 21 or 23 St. Jude mechanical valve replacement without enlargement as a control group. The patients were assessed by clinical evaluation, functional capacity, doppler and colored doppler echocardiography techniques to study the function of the prosthesis and for the evaluation of the transvalvular gradient. The mean follow-up period for the enlargement group and those without the enlargement procedures was 31.8 months and 32.5 months respectively. No difference in the functional capacity was found between the two groups.

Patients with an enlargement procedure and 21 St. Jude AVR showed a mean transvalvular gradient of 34 mmHg compared with 24.6 mmHg for the control group, where as those with an enlargement procedure and a 23 St. Jude AVR showed a mean transvalvular gradient of 23.16 mmHg compared with 24.5 mmHg for the control group. The hospital mortality for Nicks procedure was 4 patients (6.45 9) and that for Manouguian procedure was 3 patients (16.66 %). The total hospital mortality was found to be (8.86 %) (7/79) patients.

For smal aortic annulus the application of No: 21 St. Jude mechanical valve appeared to show a sufficient result hemodynamically.

Instead of the lengthy cross-clamp duration for aortic annulus enlargement procedures with a concealed increament in morbidity and mortality, a more simple and shorter posterior approach procedure for the enlargement of the aortic valve has provided hemodynamic advantage related to the insertion of a larger prothesis in addition to the insured reduction in the morbidity and mortality.