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Biomedical subjects

O Sawatani

Publications and source records attributed to O Sawatani.

13 recordsLinked to original sources
PubMed1996

[A case of coronary artery embolism after double valve replacement].

A 69-year-old woman with combined valvular heart disease (mitral regurgitation and aortic regurgitation), ascending aortic aneurysm, and atrial fibrillation underwent double valve replacement (DVR) and, ascending aortic wall plication. The postoperative thrombo-test level was around 20%. The ST elevation on ECG (II, III, aVFm, V4 approximately V6) with chest pain were recognized on the 13 th postoperative day. She was diagnosed as having acute myocardial infarction, and percutaneous transluminal coronary recanalization was performed immediately. The coronary angiogram showed occlusion at the left anterior descending branch (#8). This lesion could be recanalized by 6,000 U plasminogen pro activator (pro-UK) administration. The cineangiogram on the 35th postoperative day, revealed complete recanalization of this occlusion. Several cases of acute myocardial infarction associated with valvular heart diseases has been reported previously in Japan. However, there has been no report, except for this case, demonstrating occlusion in the coronary artery after prosthetic replacement and successful PTCR. So, this case is the first report on that point.

Aged↗
PubMed1989

Epoxy compounds as a new cross-linking agent for porcine aortic leaflets: subcutaneous implant studies in rats.

The epoxy group of the epoxy compounds has an oxygen arm that can work as a flexible joint in a cross-linking bridge and can block not only the amino group but also the carboxy group of collagen peptide. The purpose of this study is to evaluate the anticalcification efficacy of the epoxy compounds as a cross-linking agent for xenograft bioprostheses. Porcine aortic leaflets were treated with 2% epoxy compounds and implanted in subcutaneous layer of 4-week-old rats. Measurement of calcium content showed that epoxy-treated implants received a minimal calcification: mean 0.64 micrograms/mg dry weight leaflet tissue (range 0.5-0.8; N = 7) at 1 month; mean 0.94 microgram/mg (range 0.3-1.3; N = 9) at 2 months; and mean 1.2 micrograms/mg (range 0.5-2.1; N = 10) at 3 months. Natural leaflets contained calcium of mean 0.43 microgram/mg. By contrast, glutaraldehyde-preserved implants were severely calcified: mean 91 micrograms/mg (range 41-130; N = 11) at 1 month; mean 136 micrograms/mg (range 73-205; N = 16) at 2 months; and mean 170 micrograms/mg (range 90-214; N = 21) at 3 months. The epoxy compounds provide more pronounced anticalcification effects than the glutaraldehyde under pressure load-free subcutaneous circumstances.

Animals↗
PubMed1988

Stent creep of porcine bioprosthesis in the mitral position.

Stent creep, often associated with valve malfunction, is said to play an important role in the long-term performance of a porcine bioprosthesis. We have measured the angle of the stent post showing maximal inward bending (IBA) on 44 mitral porcine bioprostheses. All of them were explanted 1 to 12 years (mean explant time, 7.8 years) postoperatively at reoperation. Patients included 19 men and 25 women, ranging in age from 24 to 66 years (mean age, 47.2 years). Mean IBA was 12.7 +/- 4.2 [SD] degrees in 14 valves implanted for 7 years or less and 16.4 +/- 5.8 degrees in 30 valves implanted 8 years or longer (p less than 0.05). There was no significant difference in IBA among valves based on type (25 Hancock valves, 15.0 +/- 4.7 degrees; 10 Angell-Shiley valves, 16.2 +/- 8.6 degrees; and 9 Carpentier-Edwards valves, 14.4 +/- 3.7 degrees). There was a significant difference in IBA based on valve size (37 valves measuring 25-29 mm in diameter, 16.3 +/- 5.1 degrees; and 7 valves measuring 31 mm in diameter, 9.9 +/- 5.1 degrees; p less than 0.05). IBA showed a tendency to have a large value in a heart with a small left ventricular end-systolic volume. We conclude that (1) stent creep is not related to the materials or designs of the stent post, but tends to increase with passage of time in place; and (2) compression of the left ventricular wall is one of the main causes of stent-post bending.

Adult↗
PubMed1988

In vitro analysis of performance of porcine xenografts with inward bending of stent posts: real-time measurement of valve orifice area using an area meter.

The influence of inward bending of the stent posts on bioprosthetic valve function was assessed in a hydromechanical simulation of the left heart. A Carpentier-Edwards mitral xenograft (31 mm) and an aortic xenograft (27 mm) were used. Valve function was evaluated before and after the stent posts were bent inward 15 degrees by suture constriction of the tops of the three posts. To evaluate the effects of the stent-post deformity on valve performance, the mean transvalvular pressure drop during steady flow, the bioprosthetic valve orifice area, and the maximum valve opening and closing speeds during pulsatile flow were measured using an area meter. Steady-flow data showed identical transvalvular pressure drops, and no significant difference in valve performance was detected in the pulsatile-flow study under the two experimental conditions (i.e., normal valve and deformed valve). We conclude that a 15-degree inward bending of the stent posts does not appreciably affect valve function in vitro.

Aortic Valve↗
PubMed1988

[Clinical study of "stent creep" in porcine bioprosthesis].

Stent creep is often associated with malfunction of bioprosthesis. We measured the inward bending angle of the stent-post showing maximum bending (IBA) on 42 mitral porcine xenografts retrieved 1 to 12 yrs (mean 7.7 yrs) postoperatively at reoperation. Patients were 12 men and 28 women, ranging in age from 26 to 58 yrs. Mean +/- S.D. for IBA was 12.7 +/- 4.2 degrees(ds) in 14 valves being implanted for less than 7 yrs and 16.9 +/- 5.5 ds in 28 valves longer than 8 yrs (p less than 0.05). There was a significant difference in IBA between 36 valves of 25-29 mm size (16.3 +/- 5.1 ds) and 6 valves of 31 mm (10.3 +/- 5.5 ds) (p less than 0.05), but no significant difference between 23 Hancock valves (15.5 +/- 4.4 ds), 10 Angell-Shiley valves (16.2 +/- 8.6 ds) and 9 Carpentier-Edwards valves (14.4 +/- 3.7 ds). IBA showed a tendency to have large valve in the heart with small left ventricular end-systolic volume. The results showed that stent creeping phenomenon was not related to the material or design of stent-post, but tended to increase with passage of time in place. Furthermore, it was suggested that stent creep was induced by the mechanism of compression of the stent by the left ventricular wall.

Adult↗