Doppler echocardiography of 119 normal-functioning St Jude Medical mitral valve prostheses: a comprehensive assessment including time-velocity integral ratio and prosthesis performance index.

The purpose of this study was to provide, in a large number of patients, comprehensive Doppler echocardiographic assessment of normal St Jude Medical mitral valve prosthesis function using Doppler-derived hemodynamic variables, including the mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio and prosthesis performance index. The pressure half-time was less than 130 milliseconds in all patients, and all but one patient had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2. There was a significant (P < .001) negative correlation between the prosthesis performance index and prosthesis size. This negative correlation suggests that there is more efficient use of the in vitro geometric orifice area with smaller prostheses.     

Contribution of autologous blood transfusion in cardiac surgery in the adult

The use of autologous blood transfusion in cardiac surgery is still controversial. This study was prospectively designed to evaluate the haemodynamic and haematological benefits of this method, with special attention to its impact on reducing bank blood requirements. Between November 1983 and October 1984, 160 patients underwent cardiac surgery with extracorporeal circulation and were randomly assigned to two groups: group I (81 patients) was the control group and group II (79 patients) received autologous transfusion following extracorporeal circulation. Blood was withdrawn immediately after the induction of anaesthesia via a jugular catheter and stored in CPD solution at room temperature. The volume of blood removed was replaced with gelatin solutions; after bypass, blood was returned to the patient. There was no difference in systolic, diastolic or mean blood pressures between the two groups. Right atrial pressure and heart rate were not statistically different in both groups. Myocardial perfusion and myocardial oxygen consumption remained unchanged in group II compared with group I. Complete haematological evaluation was carried out before and during bypass, and thereafter daily for the first twelve days of the postoperative period. There was no significative difference between the two groups in platelet counts, fibrinogen levels, prothrombin and partial thromboplastin times. During extracorporeal circulation, mean haematocrit was 22.9 +/- 0.4% in group II and 25.3 +/- 0.5% in group I (p less than 10(-3)). The mean haematocrit time course was similar in both groups during the postoperative period and returned to preoperative value at discharge.(ABSTRACT TRUNCATED AT 250 WORDS)     

High glucose prolongs cell-cycle traversal of cultured human endothelial cells

There is evidence suggesting that the diabetic state adversely affects replication of certain cell populations. We document that exposure to high ambient glucose (20 mM) induces delay in various phases of the cell cycle of human endothelial cells in primary culture. Cells in S phase were labeled with bromodeoxyuridine (an analogue of thymidine), and the cell-cycle position of the labeled cohort was analyzed by flow cytometry at successive time points. The movement of cells exposed to high glucose for 7-8 days was retarded both in S and G2 phases so that the increase in bromodeoxyuridine-positive cells over 24 h was 1.6-fold, versus 2.0-fold in control cultures. In experiments in which mitotic arrest with vinblastine was used to investigate the movement of cells out of G1 phase without interference from reentering cells, depletion of the G1 compartment was significantly inhibited in cultures grown in high glucose. The effects of chronic high glucose on cell cycle occurred while total protein synthesis was not diminished. Acute exposure to high glucose had no effect on cell-cycle traversal or cell generation time. Cell-cycle abnormalities observed in this study may relate to the DNA damage we have previously observed in endothelial cells exposed to high glucose and, if occurring in vivo, could be of pathogenetic importance for the vascular lesions and teratogenicity of diabetes.