Biomedical subjects
Publications and source records attributed to M Endo.
A composite valve prosthesis was prepared by direct suture of the ring prosthesis, which was separated from an intraluminal ringed graft, with a St. Jude Medical aortic valve. A new translocation method using this composite valve prosthesis was performed on a patient with aortic periannular abscess, with favorable result.
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.
The effects of chymopapain treatment of the canine intervertebral disc were studied in vivo by monitoring proteoglycan in the nucleus pulposus. Analysis of proteoglycan was carried out by Sepharose CL-4B (Pharmacia Fine Chemicals AB, Stockholm, Sweden) chromatography and electrophoresis. The proteoglycan was degraded to glycosaminoglycans within 1 week after chymopapain treatment. Two weeks later, a proteoglycan smaller than the original appeared in the nucleus pulposus. At 8 weeks after injection, the amount of the newly synthesized proteoglycan, similar in molecular weight to the original, had recovered to about half that of the original, although the new proteoglycan fraction was rich in hyaluronic acid. It was concluded that, following chemonucleolysis with chymopapain, the water-binding capacity of the nucleus pulposus recovered, but that the regenerated nucleus pulposus differed biochemically from the original.
To clarify the production mechanism of atrial natriuretic peptide (ANP) in right (RA) and left atria (LA) in mitral valve disease, histopathological and immunohistocytochemical analyses were performed and ANP levels were investigated by radioimmunoassay (RIA) in 28 patients. Atrial tissues were obtained during mitral valve replacement. ANP-like immunoreactivity of the myocytes applied by the avidin-biotin peroxidase complex method was observed around the nuclei of the atrial myocytes. Electronmicroscopically, immunoreactivity was observed in atrial specific granules. Light-microscopically determined intensity of the immunoreactivity was classified into 4 grades and the intensity in 100 myocytes was expressed by adding the scores of each myocyte. Mean right atrial pressure was positively correlated with the activity score in RA (r = 0.80). Pulmonary capillary wedge pressure was not correlated with the score in LA. The score in RA was significantly higher than that in LA. The ANP level in RA investigated by RIA was also higher than that in LA. Histopathological findings such as myocyte hypertrophy, degeneration and interstitial fibrosis were more severe in LA than in RA. In conclusion, longstanding atrial overloading, especially in LA, caused severe pathological damage, resulting in a smaller production of ANP. Much more ANP may be produced from RA in long-standing mitral valve disease.
This study was aimed at assessing the value of preoperative forward ejection fraction (FEF) and corrected forward ejection fraction (CFEF) as an index of postoperative myocardial function. Utilizing 34 patients with mitral regurgitation, usefulness of the preoperative FEF and CFEF was evaluated with special reference to incidence of postoperative low output syndrome (LOS) and improvement in the New York Heart Association (NYHA) classification, comparing other indices of left ventricular function such as cardiac index (CI), stroke index (SI), left ventricular end-diastolic volume index (LVEDVI) and left ventricular end-systolic volume index (LVESVI). There was a significant correlation between FEF and CI, SI, LVEDVI or LVESVI, and between CFEF and CI, SI, LVEDVI or LVESVI. The FEF and CFEF, however, were better indicators for predicting the occurrence of postoperative LOS than EF. Postoperative improvements in the NYHA classification were parallel to that of the FEF and CFEF changes, but did not coincide with that of the EF. Based on these findings, it is concluded that FEF and CFEF are more useful indicators than EF for evaluation of left ventricular myocardial performance in patients with mitral regurgitation.
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Postoperative biliary stasis is a common state before the onset of postoperative acute cholecystitis. In order to study its characteristics and methods of prophylaxis, we examined the frequency of biliary stasis and postoperative recovery of gallbladder contractility ultrasonographically from the 2nd to the 28th postoperative day in 43 esophagectomy cases. A retrospective study in 17 patients revealed a high incidence of biliary stasis during the early postoperative period and improvement by the initiation of enteral nutrition. Furthermore, the contractility of the gallbladder recovered remarkably soon after the operation. This first randomized prospective study concerning prophylaxis of biliary stasis in 26 patients showed that postoperative biliary stasis was prevented by early initiation of enteral nutrition.
The 65-year-old male patient of esophageal cancer before operation suffered from lobar pneumonia. Bacteriological examination identified MRSA in his sputum and catheter tip. None of the cefem type antibiotics were effective, but CLDM and MINO were so much effective against that. We studied 47 cases of esophageal cancer which received operation last year. In many bacteria which were identified in the sputum and pus, MRSA occupied 30% as well as Pseud. aeruginosa. In the preoperative period enteral nutrition (ED) may be acceptable, if possible, as nutritional support alternative to TPN.
We studied the effect of early postoperative enteral hyperalimentation on the nutritional state and hormones in digestive organs in twenty patients who underwent resection of thoracic esophageal carcinoma and reconstruction of new esophagus. Following results were obtained. 1. Although enteral hyperalimentation was started in the early postoperative period (postoperative 3 day), the incidence of complications including diarrhea was decreased dramatically and satisfactory nutritional effect was obtained due to the development of many excellent chemically defined enteral nutrients. 2. Gut hormones including CCK showed the same response as in the preoperative period to the loading of enteral nutrients. And that, it is suggested that the response of CCK is affected by the lipid content in the nutrients and that this response was effective to prevent the postoperative biliary stasis. 3. Enteral nutrition made it possible to self-regulate water absorption from digestive organs, to control body fluid volume and to prevent over hydration or hypovolemia to comparison with parenteral nutrition.
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One hundred and ninety-four patients underwent valve replacements with the glutaraldehyde-preserved porcine bioprostheses (133 Hancock valves, 39 Angell-Shiley valves, 22 Carpentier-Edwards valves and 3 other valves) from 1974 through 1979. There were 105 women and 89 men, whose age ranged 18 to 62 (mean 38.8) years. One hundred and eighty-two patients had mitral bioprosthetic valve replacement (BVR)s, of which 52 had combined aortic mechanical valve replacements, 8 had aortic BVR's, 3 had tricuspid BVR's and 3 had multi-BVR's. Operative mortality was 10.8%. Only one patient was lost to follow-up. Cumulative duration of follow-up is 1421 patient-years. Linearized rate of anticoagulant related hemorrhage, thromboembolism (TE), prosthetic valve endocarditis (PVE), primary tissue failure (PTF) and valve dysfunction (VD) were 0.07, 1.62, 0.49, 2.74 and 3.66% per patient-year. Actuarial freedom from TE, PVE, PTF and VD were 87.0 +/- 2.7%, 95.6 +/- 1.5%, 65.2 +/- 4.9% and 56.9 +/- 5.6% at 13 years. Actuarial survival rate was 67.4 +/- 4.0% at 13 years. Long term follow-up after valve replacement with porcine bioprosthetic valve confirms low thrombogenicity. But primary tissue failure was the chief cause of valve dysfunction and represent a major problem. At this time, we are going to use porcine bioprosthetic valve in the selected patients, that is in the situations in which anticoagulation is contraindicated.
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Between 1981 and 1987, valvular surgery was performed in 988 patients, 27 of which were dead before discharge. Among them, 14 patients of cardiac deaths due to low cardiac output syndrome (LOS) and arrhythmias were analyzed to withdraw factors correlated with their cause of death. There was a tendency for the patients with stenotic valvular disease to die of LOS and regurgitant valvular lesions of arrhythmias. Statistical analysis showed the cause of deaths were multifarious including pulmonary, hepatic and renal failure, so no definite factor was pointed out. Case study of typical limited and extended surgical indications revealed (1) the patients with mitral stenosis combined with organic tricuspid regurgitation and RV/LV EDVI ratio over 1.5, and (2) the patients with aortic insufficiency and LVEDVI over 400 ml/m2 or LVESVI over 300 ml/m2 were candidate for hospital death after valve replacement. Extended approach for those patients should be two staged heart transplantation using ventricular assist device.
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