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Biomedical subjects

H Fukumasu

Publications and source records attributed to H Fukumasu.

At least 37 records · Page 2Linked to original sources
PubMed1981

A seven-month survival of a calf with an artificial heart designed for human use.

A Jarvik-7 type of pneumatic artificial heart, which was specifically designed to fit the anatomy and hemodynamic requirements of human patients, was implanted in a calf in an experiment to test the hemodynamic performance of the artificial heart. The experiment lasted for 221 days, longer than any animal had ever lived without its natural heart, despite the fact that the calf increased its body weight to 171 kg. The calf showed typical signs of low cardiac output before its death, but the direct cause of death was intestinal bleeding. At autopsy, it was discovered that the low cardiac output was due to severe pannus around the left inflow valve, as diagnosed earlier by changes in the pneumatic pressure wave form.

Animals↗
PubMed1981

Preclinical evaluation of intra-aortic balloon pumping for pediatric use.

Small intra-aortic balloons (0.75 ml to 5.0 ml) mounted on small catheters (4.0F and 5.0F) have undergone in vitro testing with the Utah Heart Driver and in vivo evaluation with 3 different pumping modules. In small animals with reduced cardiac output from acutely produced mitral regurgitation, intra-aortic balloon pumping effectively reduced aortic peak systolic pressure, lowered aortic end-diastolic pressure and reduced left atrial pressure. In addition, the Datascope system most effectively augmented diastolic pressure and increased aortic forward and negative flow as compared with 2 other pumping modules. The total system has been adequately and experimentally evaluated and is ready for clinical use in infants and small children.

Animals↗
PubMed1980

Recovery of cardiac function with total transapical left ventricular bypass.

Transapical left ventricular bypass which withdraws blood directly from the left ventricular apex through a roller pump and outflow filter with return to the femoral artery has been applied in 6 patients with cardiac failure. All patients required total TALVB (with the aortic valve closed) for periods of one to 144 hrs, and 2 patients had recovery of life-sustaining myocardial function, allowing removal of the TALVB system. One patient had complete recovery without other organ dysfunction. Total TALVB continuously decompresses and unloads the left ventricle throughout systole and diastole, and maintains the circulation in otherwise terminal circumstances.

Adult↗
PubMed1980

Reoperative surgery in calves with a total artificial heart.

Two surgical techniques have been developed in our laboratory to deal with identifiable problems in long-term artificial heart experiments. A right throacotomy is used to deal with problems such as extensive bleeding, which occur in the immediate postoperative stage of the experiment, while a left thoracotomy is used in cases in which the original implantation is preceded by more than one week, since extensive adhesions complicate the right thoracotomy at that stage. Pulmonary problems have been eliminated as primary cause of difficulties after reoperation, but infection remains a serious problem.

Animals↗
PubMed1979

Intra-aortic balloon pumping device for infants.

The miniature components of an intra-aortic balloon pumping system (IABP) have been successfully developed in this laboratory and have been effectively tested both in vitro and in 32 in vivo experiments using small animals weighing 3.5--18 kg. It is reasonable to assume that IABP can be successfully employed for clinical use in infants and small children.

Animals↗
PubMed1979

Six-month survival of a calf with an artificial heart.

A pneumatically powered artificial heart, constructed primarily from a polyurethane, was implanted in the chest of a calf and supported the calf for more than 6 months. The heart, which was designed to fit in the chest of a 90 kilogram calf, was able to suppor the animal when it weighed 180 kilograms. During the first 105 days the calf remained strong and healthy. The animal grew progressively weaker after day 106, and by day 160 right heart failure became apparent. The principal cause of the right heart failure was an obstructive growth between the right atrium and the right ventricle. An attempt to correct the problem on day 184 with an artificial heart resulted in the animal's death.

Animals↗
PubMed1978

Transapical left ventricular bypass: a method for partial or total circulatory support.

A simple cannula method of partial or total left ventricular bypass, utilizing a roller pump and outflow filter, has been developed and applied clinically. One of three patients with severe cardiac and multisystem failure was pumped with total left ventricular bypass for six days and decannulated with recovery of myocardial function after nine days. These results are encouraging and suggest that a number of patients could be salvaged from temporary cardiac failure with a simple cannula-roller-pump bypass system.

Adult↗
PubMed1978

The beat goes on: status of the artificial heart, 1977.

After two decades of continuous research on the artificial heart, survival times of experimental animals indicate that clinical application of such a device is definitely feasible. However, a number of problems remain to be solved. Durability of the device, infection, pannus formation at the interface between the device and natural tissue and thrombosis within the device appear to be the major problems. Development of an implantable power source is also an area of important research. Questions of efficiency, cosmetic and psychological acceptability and cost are just beginning to be considered.

Animals↗
PubMed1978

Prolonged, transapical left ventricular bypass (TALVB) in sheep and man.

Transapical left ventricular bypass has been demonstrated in normal sheep and one lamb. Recently, TALVB was applied in 3 clinical cases of cardiac failure, with recovery of myocardial function in one patient after 9 days of bypass (6 days total TALVB). These studies suggest that LV apical cannula-roller pump bypass with low dose heparin anticoagulation and secondary surgery to remove the cannula may salvage some patients now dying of temporary cardiac failure.

Adult↗