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Biomedical subjects

L D Joyce

Publications and source records attributed to L D Joyce.

47 records · Page 3Linked to original sources
PubMedDate not supplied

The Nimbus Hemopump: a new left ventricular assist device that combines myocardial protection with circulatory support.

Recent advances in hemodynamic support can allow patients at high risk for cardiovascular collapse to become candidates for coronary interventions. A new axial blood flow pump has recently been developed and made available for clinical testing. This intravascular pump utilizes an Archimedes screw pump rotating at 25,000 rpms to provide a flow of 2 to 3.5 liters/minute. The 7 mm inlet cannula of the cable driven pump is delivered across the aortic valve. The pump discharges blood into the descending aorta. This design does not require a membrane oxygenator. This pump would be expected to: 1) provide circulatory support irrespective of heart arrhythmias; 2) provide left ventricular unloading and 3) lack the fluid and coagulation abnormalities of prolonged cardiopulmonary bypass. This unique device offers great promise to the interventional cardiologist.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Registry report. Use of total artificial hearts: summary of world experience, 1969-1991.

Eleven models of total artificial hearts (TAHs) have been used for transient or permanent circulatory support in patients with failing hearts. From April 4, 1969 to July 1, 1991, 230 TAHs were used in 226 patients (four patients received a second TAH) at 39 centers worldwide. Five patients received a Symbion TAH as a permanent circulatory support device; the remaining 221 received TAHs as bridges to cardiac transplantation. The principal investigators received written requests for demographic and clinical information after each implant and annually thereafter to assess survival. The mean patient age (+/- SD) was 43 +/- 12 years (range, 13-69 years); 88% of patients were men. The primary indications for implantation were deterioration while on a transplant waiting list (34%) and acute cardiogenic shock (33%). The duration of implantation ranged from < 1 to 603 days; 65% received heart transplants. The incidence of infection and embolic events occurring during implantation times were 36% and 9%, respectively (stroke, 5%; transient ischemic attacks 4%). Most deaths were caused by sepsis (33%) and multiorgan failure (32%) during the implantation period; sepsis (36%) and rejection of the donor heart (19%) were responsible for most deaths in patients who died after transplantation. The 1 year survival rate was 37% for all patients receiving a device and 50% for those who received a transplanted organ. In the overall Symbion TAH population (187 patients), 40% survived 1 year and 56% of the transplanted group survived 1 year; 39 non-Symbion TAH implants resulted in one long-term survivor (3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Summary of the clinical use of the Symbion total artificial heart: a registry report.

Several models of total artificial hearts have been used for transient or permanent circulatory support in patients with decompensation. The most successful and widely used device, however, has been the Symbion total artificial heart. From Dec. 12, 1982, to Jan. 1, 1991, 180 Symbion total artificial hearts were implanted in 176 patients in 28 centers. Five patients received a Symbion total artificial heart as a permanent circulatory support device, whereas 171 patients received the device as a bridge to heart transplantation. Of the 175 bridge devices (171 patients) 141 were Symbion J7-70 hearts and 34 were Symbion J7-100 hearts. Four patients received two total artificial hearts, the second one after the failure of a transplanted heart because of either rejection (two patients) or donor heart failure (2 patients). Most of the recipients were males (152). The age was 42 +/- 12 years (mean +/- SD) with a weight of 74 +/- 14 kg. The most common indications for implantation included deterioration while awaiting heart transplant (36%) and acute cardiogenic shock (32%). The cause of heart disease was primarily ischemic (52%) and idiopathic (35%) cardiomyopathy. Duration of implantation ranged from 0 to 603 days (mean 25 +/- 64 days). One hundred three (60%) patients had the device less than 2 weeks, 37 (22%) between 2 to 4 weeks and 31 (18%) more than 4 weeks. Complications during implantation included infection (37%), thromboembolic events (stroke 7%, transient ischemic attack 4%), kidney failure requiring dialysis (20%), bleeding requiring intervention (26%), and device malfunction (4%). Of the 171 patients, 118 (69%) underwent orthotopic heart transplantation. Actuarial survival for all patients with implants was 62% for 30 days and 42% for 1 year, and for patients with transplants was 72% for 30 days and 57% for 1 year. The main causes of death were sepsis (33%), multiorgan failure (21%), and posttransplant rejection (10%). The results indicate a relative success of this treatment for patients with an otherwise fatal prognosis. Moreover, as the demand for donor organs far exceeds availability, continued investigation of total artificial hearts is justified.

Actuarial Analysis↗
PubMedDate not supplied

Induction immunosuppression for patients bridged to transplantation.

From January 1987 through July 1989, nine patients (eight male, one female) underwent bridge to transplantation and were managed with a modified immunosuppression regimen based around the monoclonal antibody OKT3. Six patients were bridged with the Jarvik-7 70 cc total artificial heart, four patients with centrifugal ventricular assist devices, and one patient with a Novacor left ventricular assist system. In two patients two devices were used. There was one patient death at 29 days after transplantation because of acute rejection. One other patient had a rejection episode 368 days after transplantation, for an overall rejection incidence of 0.22 episodes/patient. Four infections occurred, and all were viral--three cytomegalovirus and one mumps. Posttransplant complications involving other organ systems were minimal. In follow-up, from 2 to 29 months, six patients are in New York Heart Association functional status class I and one is in class II. Six patients are not taking steroids. The serum cholesterol level in the patients not receiving steroids at 6 and 12 months is 151 +/- 11 and 171 +/- 23 mg/dl (+/- SEM), respectively. Because of these results we have expanded our indications for the modified regimen using OKT3 in patients with preoperative organ system dysfunction, in diabetic patients, in pediatric patients, in female patients, and in posttransplant patients who require mechanical assistance.

Adolescent↗
PubMedDate not supplied

Experience with the Sarns centrifugal pump as a ventricular assist device.

The authors used the Sarns centrifugal pump (Sarns 3M, Ann Arbor, MI) as a ventricular assist device (VAD) in 30 patients between May 1985 and February 1990. Sixteen patients were unweanable from cardiopulmonary bypass at the time of surgery; nine were patients who developed cardiogenic shock postoperatively in the intensive care unit. One was a donor organ failure; one had a failed PTCA; and one an acute myocardial infarction with cardiogenic shock preoperatively. Two patients were bridged to cardiac transplantation. Of the 28 nontransplant candidates, 20 (71.4%) were weaned successfully, 14 (50%) were discharged from the hospital, and 13 (46%) are alive from 1 to 46 months postoperatively (mean, 21.1 months). Three patients received right ventricular support alone; all three were weaned, and two (66.7%) were discharged. Ten patients received left ventricular assistance alone. Six (60%) were weaned, and four (40%) were discharged. Two patients received left ventricular support initially but were taken back for right VAD insertion because of right-sided heart failure; one (50%) is alive. Fifteen patients received biventricular support. Eleven (77.3%) were weaned, and eight (53.3%) were discharged. Patient ages ranged from 19 to 73 years, with a mean age for men of 59 years and 50.5 years for women. There were no thromboembolic events. Various clinical parameters were evaluated to determine effect on weanability and survival. These results show survival equivalent to any other VAD at this time. The centrifugal pump is a convenient and effective means of maintaining ventricular support in individuals who are believed to have salvageable myocardium.

Cardiopulmonary Bypass↗
PubMedDate not supplied

Nine year experience with the clinical use of total artificial hearts as cardiac support devices.

One hundred sixteen total artificial hearts (TAH) were implanted in 113 patients by 29 centers between April 4, 1969 and March 1, 1988. Five were permanent and 111 were temporary implants (3 patients received second implants). Eight different types of TAHs have been used. The ages ranged from 15 to 62 (mean age: permanent 57, temporary 42). Sixty-seven percent (72/108) of patients receiving the TAH for temporary support were transplanted; 6 patients were waiting for a transplant. Forty-seven percent (34/72) were alive after transplantation. Of the 92 patients receiving the Jarvik TAH (the most frequently used device) as a temporary device, 67% (62/92) were transplanted (6 currently supported) and 55% were alive after transplantation; 85% were back to work, with a normal life-style. The thromboembolic rate for patients who received the device as a temporary support was 10%, with 3 patients having residual sequellae. No deaths resulted from mechanical failure. Experience to date suggests that the use of the TAH as a temporary device can be beneficial if patients are carefully selected.

Adolescent↗
PubMedDate not supplied

Use of the mini Jarvik-7 total artificial heart as a bridge to transplantation.

A 40-year-old woman was maintained on a mini Jarvik-7 total artificial heart for 45 days, during which time she recovered from a viral cardiomyopathy and multiple organ failure. The total artificial heart and driver were free of mechanical dysfunction, and there was no evidence of thromboembolic complications. The patient was maintained on hemodialysis for 26 days, at which time kidney function returned to near normal. The patient underwent an uneventful heart transplant and is now alive at 4 months after transplantation.

Adult↗
PubMedDate not supplied

Summary of the world experience with clinical use of total artificial hearts as heart support devices.

A review of the world experience with the implantation of total artificial hearts has been carried out. Thirteen centers throughout the world have implanted 27 total artificial hearts in 26 patients. Eight different types of total artificial hearts have been employed. As of June 1, 1986, five of these individuals have had implants for permanent support. Of the other twenty-one patients, three patients died while on a total artificial heart, seven patients died following transplantation, two patients are waiting for transplant, and nine patients have successfully been transplanted and are presently alive. Various clinical preoperative and postoperative parameters are analyzed in this investigation.

Adult↗
PubMedDate not supplied

Surgical positioning of the Jarvik-7 artificial heart.

The Jarvik-7 total artificial heart has been implanted in 18 patients at the time of this writing. Eleven patients received the 100 ml heart, and the remaining seven were treated with the 70 ml device. To date, five patients have been implanted for permanent use with an average survival in excess of 9 months, and the longest survival is more than 1 1/2 years following implantation of the heart. Complications related to positioning were a contributing factor in the death of one patient. Thirteen patients have received the Jarvik-7 heart as a bridge to transplant. Three died before transplant, and the remaining ten have been transplanted. To date, all are alive, several are home and in excellent condition, and several are still hospitalized but are expected to be released shortly. Three patients have experienced serious complications after transplantation. One patient rejected her heart transplant, was reimplanted with the artificial heart, and now has been sustained for more than 3 months. At this time she is in good condition awaiting a second donor. Selection of the appropriate size Jarvik-7 artificial heart for the individual patient can best be made based on measurements of thoracic dimensions obtained from a computed tomography scan and calculation of body surface area. The appropriate medial or lateral positioning can be determined and decisions concerning the lengths of the grafts and cuffs, excision or nonexcision of the left pericardium, and air drive line position can be made. The Jarvik-7 heart can be successfully used in patients from 50 kg. However, at the lower size limit in patients from approximately 50 to 65 kg, the risk of fit complications is the greatest and availability of an even smaller model heart would be desirable.

Adult↗
PubMedDate not supplied

Indexes of hemolysis in human recipients of the Jarvik-7 total artificial heart: a cooperative report of fifteen patients.

The degree of red cell destruction in human recipients of the total artificial heart has not previously been described. Fifteen patients implanted with a Jarvik-7 total artificial heart for either temporary or permanent heart replacement were reviewed. Clinically significant elevations of plasma free hemoglobin and serum lactate dehydrogenase were demonstrated in patients receiving the standard (100 ml) Jarvik-7 containing Medtronic-Hall valves and powered by pulses of compressed air delivered at a dP/dT of 6000 mm Hg/sec to 8000 mm Hg/sec. Reduction of the dP/dT by drive unit modification greatly reduced the plasma free hemoglobin and lactate dehydrogenase in subsequent patients. Introduction of the smaller (70 ml) total artificial heart was not associated with greater hemolysis once dP/dT had been reduced. With the current driver delivering systolic pulses at less than 4500 mm Hg/sec, both size hearts are free of clinically relevant hemolysis. In addition, it appears that attempts to eliminate hemolysis completely by lowering heart rates, cardiac outputs, or driving pressures are potentially dangerous. The eventual development of embolic cerebrovascular accidents is associated statistically with heart rates below 80 beats/min. These data reassure implanting physicians that the updated Jarvik-7 total artificial heart system does not induce worrisome hemolysis. In addition, this study has uncovered a link between eventual cerebrovascular accident and low heart rate, implying that purposeful application of heart rates around 100 beats/min may provide a significant margin of protection against cerebrovascular accident during implantation.

Adult↗