Aortic valve replacement. A randomized study comparing Björk-Shiley and Lillehei-Kaster disc valves. Haematological evaluation

Late chronic hemolysis after valve replacement for aortic stenosis. Relation to residual hypertrophy and impaired left ventricular function

The relationship between intravascular hemolysis induced by aortic valve prosteses and patient status/left ventricular (LV) function (radionuclide cardiography) was examined in 63 patients of 65 who were alive ten to seventeen years after valve replacement (1965-1973) for aortic stenosis. Serum-lactic dehydrogenase (LDH) exceeded upper reference limit in 62 patients and S-haptoglobin (HAPTO) was reduced in 62. One patient with normal LDH had reduced HAPTO and elevated plasma-hemoglobin. Anemia was noted in 4 patients (6%). S-LDH was higher in men than in women (p less than 0.05), in patients with increased ECG hypertrophy score than in those with a normal score (p less than 0.05), in patients with NYHA class II-III than in those with class I (p less than 0.05), in patients with abnormal LV function than in those with a normal radionuclide study (p less than 0.05), in patients with a pathologic Q wave in the ECG than in those without (p less than 0.05), and in patients with a Starr Edwards cloth-covered (SECC) prosthesis than in those with other types (p = 0.07). ECG hypertrophy score correlated directly with LDH (r = 0.33, p = 0.008) and inversely with LV ejection fraction (r = -0.57, p less than 0.0001), peak ejection rate (r = -0.47, p less than 0.0001), and peak filling rate (r = -0.41, p less than 0.001). Multiple linear regression analysis revealed that LDH was accounted for by ECG hypertrophy score (p = 0.001), SECC prosthesis (p = 0.04), and male gender (p = 0.05). Hypertrophic malfunctioning left ventricles may be responsible for higher degrees of turbulent flow characteristics in the vicinity of prosthetic valves in the aortic position and, by inference, explain the increased tendency toward hemolysis in these patients.

Seven and one-half years' experience with the Medtronic-Hall valve

The Medtronic-Hall valve was developed to improve on existing tilting disc valves by reducing the risk of valvular thrombosis. This was to be accomplished by improving the hemodynamics and by allowing the disc to move downstream away from the orifice during opening. The valve was also designed for maximal structural durability to minimize the risk of mechanical breakage. With more than 1,000 Medtronic-Hall valves implanted since 1977, the clinical results have been very encouraging. The rates of thromboembolism and thrombosis are low, there have been no mechanical failures and the hemodynamic function, especially with the smaller valves, is excellent.

Vigorous physical training after aortic valve replacement: analysis of 10 patients

Improved prosthetic aortic valves have reduced the incidence of complications to a point where it can be hypothesized that functional class I subjects after aortic valve replacement (AVR) should adapt to a vigorous training program without a significant increase of hemolytic activity or clinical signs of prosthesis malfunction. To test this hypothesis, 10 men (mean age 52 years) who had undergone AVR (7 Björk-Shiley and 3 Lillehei-Kaster) were submitted to an 8-week training program on ergometer, 3 times/week, from 60 to 80% of individual maximal heart rate. Ten other men who had undergone AVR but did not participate in the training program were control subjects. The exercise program produced significant improvements in posttraining maximum tolerated ergometer work load (210 kpm, p less than 0.001), in maximum total body oxygen consumption (5 ml/kg X min-1, p less than or equal to 0.01) and in double product at submaximal work load (-5,126, p less than or equal to 0.01). After training, hemoglobin decreased by about 1 g% (p less than or equal to 0.05) and hematocrit, reticulocyte counts and haptoglobin did not change significantly. Serum LDH and serum AST did not increase. Pre- and post-training echocardiograms did not show detectable alterations. Thus, patients with AVR who are in functional class I can adapt to a physical exercise program without significant adverse effects.

Aortic valve replacement. A randomized study comparing the Björk-Shiley and Lillehei-Kaster disc valves. Long-term results

Three hundred patients were selected at random in order to compare the Björk-Shiley (B-S) and Lillehei-Kaster (L-K) valves in the aortic position. The mean follow-up time was 4 3/4 years (range 3 1/4-7 years). There were 15 late deaths in the B-S group and 23 in the L-K group. The incidence of sudden and unexpected deaths was much higher in the L-K than in the B-S group (10:1). The 7-year actuarial survival rate was 82% in the B-S and 76% in the L-K group. In both groups the survival rate was higher in patients with large valves than in those with small valves; in the L-K group this difference was significant (p less than 0.02). The overall thrombo-embolic rate was 3.2 per 100 patient years in the B-S and 2.8 in the L-K group. Valve thrombosis occurred in 3 patients with B-S valves and in 4 with L-K vales. One of the L-K valves was thrombosed early after operation due to faulty suture technique. Of the long-term survivors of working age 80% in the B-S and 70% in the L-K group returned to work. There was a close correlation between functional capacity (NYHA) and the employment rate.

Aortic valve replacement. A randomized study comparing the Björk-Shiley and Lillehei-Kaster disc valves. Transvalvular regurgitation and occurrence of paravalvular fistulas

Three hundred patients were selected at random in order to compare the Björk-Shiley (B-S) and the Lillehei-Kaster (L-K) valves in the aortic position. The transvalvular regurgitation was evaluated by peroperative flow recordings in 97 cases. The leakage was found to be 7.6% and 7.5% of forward flow in the B-S and L-K valves, respectively. The regurgitant flow pattern, however, was different in the two groups, as leakage on closure was significantly larger in the L-K valves, and the leakage after closure of the disc was significantly larger in the B-S valves. Follow-up cine-aortography was carried out two years postoperatively in 91 patients. The contrast leakage through the valves was found to be minimal (Grade I) in about 90% in both groups. In one patient with a L-K valve no leakage could be demonstrated. In the remaining patients the leakage was moderate (Grade II). Paravalvular fistulas were demonstrated in three patients from each group. In one patient the paravalvular regurgitation was marked (Grade III), in the others moderate (Grade II). Cine-aortography was also carried out in a further 9 patients, in whom a paravalvular leakage was suspected according to clinical follow-up examinations. In four of these patients a paravalvular regurgitation was demonstrated. The leakage was moderate in two patients and severe (Grade IV) in another two, who were successfully re-operated on.