Haemodynamic changes in patients with high pulmonary vascular resistance after mitral valve replacement. Comparative study between use of unstented aortic homograft valves and Starr-Edwards prostheses.

The clinical and haemodynamic responses to mitral valve replacement were studied in 36 patients with a pulmonary vascular resistance of 4 units or above. In ig patients, I3 women and 6 men (mean age 49-7 years) Starr-Edwards prostheses were used. In I7 patients, 7 women and IO men (mean age 53 6 years) fresh un- stented aortic homografts were inserted. In the latter group, 3 patients had, in addition, homograft replacement of the aortic valve. Both groups showed considerable symptomatic relief after operation. Reduction in indirect mean left atrial pressure, pulmonary artery systolic and mean pressure, mean pulmonary artery -mean wedge pressure, and A V oxygen difference and pulmonary vascular resistance were observed in both groups, but with the exception of pulmonary vascular resistance and the AV oxygen difference the mean falls tended to be greater in the homograftgroup than in the Starr-Edwards group. However, only thefall in mean wedge pressure and the change in right atrial pressure were shown to be statistically more significant (P< o o5) in the homo- graft group than the Starr-Edwards group. A small rise in cardiac output occurred in both groups. Pulmonary hypertension and pulmonary vascular resistance did not remain fixed as they always fell after homograft replacement of the mitral valve. The clinical and haemodynamic findings in this series suggest that patients with homograft replacement of the mitral valve have a better result than those after insertion with a Starr- Edwards prosthesis.