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Biomedical subjects

L W Miller

Publications and source records attributed to L W Miller.

107 records · Page 6Linked to original sources
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Oral anticoagulation in patients with ventricular assist devices.

Nine men aged 25-63 years (mean 42 years) received pulsatile ventricular assist devices (VADs) as a bridge to cardiac transplantation. Duration of support ranged from 8-266 days (mean 70.7 days); seven patients (pts.) were bridged with a LVAD and two received BVADs. All pts. were maintained on oral anticoagulants after initial intravenous (IV) heparin or dextran therapy. During warfarin therapy, supplemental IV heparin was used only if the prothrombin time fell below 1.5 times control (approximately 30% activity). In 639 days of support, there was one thromboembolic event due to mechanical failure, and one pt. had thrombus in the VAD which did not embolize.

Administration, Oral↗
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Treatment of cardiac allograft rejection with intravenous corticosteroids.

The treatment of cardiac allograft rejection remains complex and is influenced by a number of factors, including hemodynamic compromise, severity of biopsy grade, time after transplantation, gender, and local institutional bias. This article reports the response of 43 rejection episodes in 67 patients who underwent orthotopic heart transplantation in a 3-year period and who were treated with triple-drug immunosuppression only. Eighty-eight percent (38 of 43) of the rejection episodes were treated initially with one course (3 gm) of intravenous methylprednisolone, and 82% (31 of 38) responded. Another 7% responded to a second course of intravenous corticosteroids, and the remaining 11% of the episodes eventually required the use of antilymphoblast globulin for resolution. Twelve percent of the rejections (n = 5) were initially treated with antilymphoblast globulin, and three responded. The response of cardiac allograft rejection to intravenous corticosteroids is greater than 85%, and this should be the initial treatment in most cases of rejection. The role of advanced biopsy grade, dose of corticosteroids used, and complications resulting from this form of therapy are discussed.

Antilymphocyte Serum↗
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Bridging to heart transplantation with circulatory support devices.

Several devices are currently available for bridging to cardiac transplantation, but the efficacy of each has not been established. From September 1983 to March 1988 we supported 17 transplant candidates with mechanical assist devices. Extracorporeal membrane oxygenation (ECMO) was used to bridge two patients, external ventricular assist devices (VADs) were used in 11 patients, internal left ventricular assist systems (LVAS) were used in three patients, and implantable prosthetic replacement ventricles (TAH) were used in one patient. The 14 men and three women, aged 24 to 59 years (mean 46 years), suffered cardiogenic shock caused by ischemic (13 patients), postpartum (two patients), viral (one patient), and drug-induced (one patient) cardiomyopathy. Five patients with isolated left ventricular failure (LVF) received only left VADs, three patients with severe LVF and moderate right ventricular failure received LVAS, and nine patients with severe biventricular failure received ECMO (two patients), biventricular assist devices (six patients), and TAH (one patient). Patients were supported for periods of 1/2 to 90 days (mean 22) with flows of 2.15 to 3.39 L/min/m2. Ten patients underwent transplantation (eight of whom were discharged) and seven patients died without transplants. The two patients who received ECMO died 1 and 30 days after transplantation, in part as a result of ECMO complications. Seven patients were denied transplants because of renal failure (five patients), infection (five patients), bleeding (four patients), and cerebrovascular accident (two patients). The seven survivors were supported with VADs (five patients) or LVAS (two patients). Three had driveline infections, two had bleeding complications, two developed mediastinitis, and one each had hemolysis, cerebrovascular accident, and mechanical failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
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Heart transplantation in patients over age fifty-five years.

The age limit for heart transplantation remains undefined. The shortage of available donors coupled with fears of increased morbidity and mortality in older patients has until recently resulted in a limited application of heart transplantation in patients over age 50 years. In 1986, however, data from the International Heart Transplant Registry demonstrated that 25% of all patients undergoing this procedure were over age 55 years. This study reviews our experience with 30 consecutive patients who underwent heart transplantation over a 15-month period. There were eight patients over age 55 years (group 1) and 22 patients under age 55 years (group 2). We compared the hospital course and incidence of infection and rejection and other complications after heart transplantation between the two groups. Carefully selected patients between ages 55 and 60 years can undergo transplantation with similar expectations to younger patients for survival, complications, and rehabilitation, including employability. Caution is warranted in extrapolating these optimistic data to patients older than age 50 years.

Age Factors↗
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Mechanical circulatory assistance after heart transplantation.

Results with mechanical circulatory assistance for the treatment of profound cardiopulmonary failure after conventional heart surgery have been encouraging. Its usefulness after heart transplantation is not known. Since August 1982, eight patients (of 59 transplant patients) have required support 0 to 48 hours (mean, 19.5 hours) after transplantation. The ages of the patients ranged from 7 days to 52 years (mean, 28.4 years). Underlying recipient heart disease was ischemic in three patients, congenital in two, cardiomyopathic in two, and rheumatic in one patient. Preoperative North American Transplant Coordinators Organization (NATCO) classification was status 9 in one patient (on extracorporeal membrane oxygenation [ECMO]), status 1 in five patients, and status 3 in two patients. Reasons for graft failure, although usually multifactorial, were primarily pulmonary hypertension with right ventricular failure in five patients and pneumonia, hyperacute rejection, and fat embolus in one patient each. In three patients, there was a mismatch in graft size (too small in two adults and too large in one neonate). Graft ischemic times ranged from 75 to 229 minutes (mean, 171 minutes). Two patients received mechanical support with an intra-aortic balloon (IAB), three with ECMO, and three with a right ventricular assist device (RVAD). One of the patients on ECMO and two of the patients with an RVAD also had IABs. Duration of support ranged from 4 hours to 8 days (mean, 3.2 days). Initial hemodynamic stability was achieved in all patients. Complications were common, including sepsis in seven patients and kidney failure in five patients. Only three patients were weaned. One patient with pulmonary hypertension, who was treated with ECMO, died 36 hours after being weaned.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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Psychometric studies and clinical interviews with cochlear implant patients.

Selection of suitable candidates for an implant was a central issue in planning clinical trials. Psychological techniques were included, the purpose being to screen out individuals who, on an a priori basis, we considered cognitively and/or emotionally inappropriate. Psychological measures were further used to assess the effect of the implant on those candidates who did undergo the surgical procedure. The present paper describes the preimplant and postimplant interviews and psychometric assessment. Based on the data developed from the interviews, we concluded that the recipients of implants are in almost unanimous agreement that the implant is a very positive contribution to their lives. Tests of cognitive functioning conducted over time indicate that the implant does not impair cognitive or neuropsychological functions. Personality tests were also administered, and no significant changes in these dimensions were found.

Adult↗
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Psychological effects of cochlear implant: patient and "index relative" perceptions.

The ultimate judge of the value of a technological advance is the patient. The patient's evaluation of the cochlear implant is one way of judging its effects. A second method is from observations of the patient made by an individual in close relationship, ie, an "index relative." In order to determine implant effects as experienced by both patient and observer, we devised preimplant and postimplant questionnaires. We found that patients feel the implant gives them a greater sense of safety; self-sufficiency is considerably enhanced: emotionally negative episodes are significantly reduced; the feeling of being a burden to others is diminished; communication with others is much smoother; and, while engaging in group activities is still difficult, participation is less threatening than before the implant. The index relatives agree with these perceptions. They also are emotionally relieved because they feel the patients have a device which extends their range of mastery. In turn, the index relatives feel burdened and responsible.

Cochlear Implants↗
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Refractory immune thrombocytopenia after heart transplantation: a case report.

Chronic immune thrombocytopenia responds to steroids and splenectomy in approximately 80% of the patients. Intravenous immunoglobulin, plasmapheresis, combination chemotherapy, and androgens may help in refractory cases. This report describes the course and management of refractory immune thrombocytopenia after heart transplantation.

Autoantibodies↗
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Report of the consensus conference on candidate selection for Heart Transplantation-1993.

BACKGROUND: Despite several task forces and numerous reviews, criteria for candidate selection for heart transplantation are not uniform. METHODS AND RESULTS: This report summarizes results compiled from a survey that was reviewed at a consensus conference held before the meeting of the International Society of Heart and Lung Transplantation in 1993 in Boca Raton, Florida. The meeting was attended by representatives of 52 programs from the United States, Canada, England, and Australia. The unique feature of this report is that is represents a review of the actual practice of patient selection at some of the largest and most experienced centers in the field. Key areas of the selection process including medical and surgical alternatives to transplantation, the composition of the transplant work-up, specific inclusion criteria as well as specific psychosocial factors and specific disease etiologies and co-morbidities that might represent contraindications were extensively reviewed. In addition, the standard follow-up for a patient on an active waiting list, and criteria to remove patients from the active waiting list are described. This survey provides information and insight regarding current areas of consensus as well as disagreement regarding candidate selection for heart transplantation. CONCLUSIONS: These differences may be important when considering outcomes and possible strategies in the use of resources.

Data Collection↗
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Heart transplantation charges: status 1 versus status 2 patients.

BACKGROUND: The current health care environment mandates closer scrutiny of health care dollar allocation. To better understand the distribution of heart transplantation costs, we reviewed hospital and physician billing of patients who underwent orthotopic heart transplantation between August 1988 and September 1993. METHODS: This study is a retrospective review of 107 consecutive cases. Charges and clinical results of United Network for Organ Sharing status 1 patients (n = 46), including 17 bridge to transplantation patients, were compared with those of United Network for Organ Sharing status 2 patients (n = 57). Charges were converted to 1992 dollars. RESULTS: During the first 12 months of the study, 77% of heart transplantations were performed in United Network for Organ Sharing status 2 patients, whereas over the last 12-month period, 25% of the transplantations were performed in status 2 patients. No significant differences were found in age, gender, type of cardiomyopathy, or survival between the status 1 and status 2 groups. The length of hospitalization for the status 1 group ranged from 8 to 138 days (mean 49 days) as opposed to 5 to 82 days (mean 17.5 days) for the status 2 group (p < 0.0001). Pretransplantation hospital charges were significantly higher for the status 1 group ($47,917 to $341,215, mean $109,116) when compared with status 2 ($0 to $10,035, mean $250) (p < 0.0001). No significant difference was found in posttransplantation hospital charges between status 1 ($47,917 to $210,027, mean $95,379) and status 2 patients ($48,093 to $380,745, mean $102,265). Total charges were significantly higher (p < 0.0001) for the status 1 group ($89,910 to $512,331, mean $239,375) when compared with the status 2 group ($63,885 to $455,680, mean $128,594). Total transplantation charges for the study period were $18,341,108. This amount could have paid for 77 status 1 transplantations or 143 status 2 transplantations. CONCLUSIONS: If current trends continue and the donor pool remains the same, most transplant recipients will be status 1, resulting in a comparable number of transplantations performed at twice the charges.

Cardiomyopathies↗
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Eleven years' experience with the Pierce-Donachy ventricular assist device.

During the last decade, mechanical circulatory support has been used in patients with cardiogenic shock refractory to conventional therapy. Since 1982, we supported 77 patients (78 implants) with Pierce-Donachy external pneumatic ventricular assist devices. Forty-two patients (35 after cardiotomy, four after heart transplantation, and three with acute infarction) 15 to 71 years of age (mean age 52 years) were supported for cardiac recovery. Left ventricular assist devices were used in 16 patients, right ventricular assist devices plus intraaortic balloon were used in nine, and biventricular assist devices were used in 17. Patients were supported 0.2 to 17 days (mean 4.4 days), 18 patients (43%) were weaned, and 11 (26%) survived. Complications included acute myocardial infarction (60%), bleeding (48%), infection (38%), and renal failure (24%). Bridging to transplantation was attempted in 35 patients (one patient underwent the procedure twice), 12 to 63 years of age (mean age 40 years). Left ventricular assist devices were used 19 times, and biventricular assist devices were used 17 times. Duration of support was 0.2 to 95 days (mean 24 days). All 20 patients who underwent transplantation were discharged. Of the 15 patients who did not undergo transplantation, two were weaned and survived, whereas the remaining 13 patients (who did not undergo transplantation because of complications) died with the device in place. In the patients in the bridge to transplantation group, bleeding occurred in 26%, infection in 55%, and renal failure in 15%. In the entire group of 77 patients, the incidence of ventricular assist device-related thromboembolism was 6%, but only 4% had neurologic deficits.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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Infection after heart transplantation: a multiinstitutional study. Cardiac Transplant Research Database Group.

The incidence, causes, and impact of acute infection were analyzed among 814 consecutive patients from 24 institutions undergoing primary heart transplantation between January 1, 1990, and June 30, 1991, with mean follow-up of 8.2 months (range 0 to 18 months). Sixty-nine percent of the patients had no infections during the follow-up, whereas 31% of patients had one or more infection episodes. The cumulative incidence of infections per patient was 0.41 at 3 months, 0.55 at 6 months, and 0.62 at 12 months after transplantation. Bacterial and viral infections were most common (47% and 41% of infections), with fungi and protozoa accounting for 12%. Overall mortality per infection was 13%, but mortality with fungal infections was higher (36%, p < 0.0001). The most common organ infected was the lung, with a mortality of 23%. The probability of infection by 12 months was higher when OKT3 or antithymocyte globulin induction therapy was used (41% versus 35%, p = 0.01). The single most frequent infecting organism was cytomegalovirus, accounting for 26% of all infections. The probability of cytomegalovirus infection by 12 months was increased with a cytomegalovirus-positive donor and cytomegalovirus-negative recipient (27% versus 15% in all others, p < 0.0001) and with the use of OKT3 or antithymocyte globulin induction therapy (19% versus 12% without induction therapy, p = 0.07). Infection remains the leading cause of death after heart transplantation. The hazard function of likelihood of developing each type of infection at various times after transplantation, as well as response to therapy, are discussed.

Adolescent↗
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Cytomegalovirus after heart transplantation. Risk factors for infection and death: a multiinstitutional study. The Cardiac Transplant Research Database Group.

Cytomegalovirus infection is a major cause of morbidity and rehospitalization after heart transplantation. To assess its incidence and risk factors in the current era of heart transplantation, we analyzed cytomegalovirus infection data in 1553 patients from 26 institutions (Cardiac Transplant Research Database Group) undergoing primary heart transplantation between Jan. 1, 1990, and June 30, 1992. There were 230 treated cytomegalovirus infections in 200 patients, of which 16 were fatal (6%; 70% confidence limits 5% to 9%). Actuarial freedom from cytomegalovirus infection was 98% 1 month, 88% 3 months, and 83% 24 months after transplantation, with a peak incidence of initial infection at 2 months. Twenty-five (12%) of 200 patients with cytomegalovirus infection had recurrent cytomegalovirus infection during a mean follow-up of 13.9 months. The primary location of cytomegalovirus infection was blood in 100 infections (43%), lung in 69 (30%), gastrointestinal tract in 54 (23%), and other sites in seven patients (3%). Cytomegalovirus pneumonia exhibited the highest mortality rate (13%). Risk factors by multivariate analysis for earlier development of cytomegalovirus infection included pretransplantation cytomegalovirus serology (positive donor, negative recipient [p < 0.0001]; positive donor, positive recipient [p = 0.0002]; and negative donor, positive recipient [p = 0.02]) and cytolytic induction therapy (p = 0.05). A cytomegalovirus-positive recipient with a cytomegalovirus-positive donor had a 15% chance of having cytomegalovirus infection, whereas a cytomegalovirus-negative recipient with a cytomegalovirus-positive donor had a 24% chance. Ganciclovir treatment was administered in 227 (99%) of 230 infections. By multivariable analysis, the likelihood of a fatal cytomegalovirus infection was increased with a higher number of infections of any type during the first post transplantation month (p < 0.0001). There was no increased mortality rate in cytomegalovirus infections associated with cytomegalovirus-positive donor and cytomegalovirus-negative recipient (6% mortality rate) versus all other cytomegalovirus infections (6% mortality rate) (p = 0.9) or with OKT3 induction therapy (0% mortality rate) versus all others (noninduction and induction with other than OKT3) (1.4%) (p = 0.03). In conclusion, the biggest determinant of cytomegalovirus infection is donor and recipient pretransplantation cytomegalovirus serologic results with cytolytic induction therapy adding a small additional risk. The overall mortality rate from cytomegalovirus infections is low (7%) in the current era with rapid culture techniques and ganciclovir therapy. Cytomegalovirus infections are more likely to be fatal if there are more frequent preceding infections of any type, but mortality rates are not increased by OKT3 induction or with a cytomegalovirus-positive donor organ transplanted into a cytomegalovirus-negative recipient.

Adolescent↗
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Vascular rejection in heart transplant recipients.

Antibody medicated (vascular) rejection has recently been described in heart transplantation. We report our experience with vascular rejection in a series of 62 patients who did not receive perioperative lymphocyte antibody therapy. Sixty-five rejections were reported, of which 58 (89%) were pure cellular; five (8%) had both cellular and vascular components, and two (3%) had only vascular rejection. Vascular rejection was very common in patients in whom hemodynamic compromise developed, and hemodynamic compromise was significantly more common in vascular than cellular rejection. Treatment for vascular rejection included plasmapheresis, intravenous methylprednisolone, and cyclophosphamide. Only one death occurred in this series, and that occurred in a patient with vascular rejection where the diagnosis and initiation of therapy were delayed. The role of vascular rejection in patients with hemodynamic compromise is discussed.

Antibody Formation↗