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Biomedical subjects

O H Frazier

Publications and source records attributed to O H Frazier.

At least 199 records · Page 11Linked to original sources
PubMed1995

Myocardial revascularization with laser. Preliminary findings.

BACKGROUND: We assessed the transmyocardial laser revascularization (TMLR) as sole therapy in patients with symptomatic coronary artery disease refractory to interventional or medical treatment. METHODS AND RESULTS: Thirty-one patients were evaluated with positron emission tomography (PET), dobutamine echocardiography, 201Tl single-photon emission computed tomography (201Tl-SPECT), and multigated acquisition radionuclide ventriculography (MUGA). TMLR was performed in 21 patients who had demonstrable ischemia in viable myocardium. The mean Canadian Cardiovascular Society (CCS) angina class was 3.70 +/- 0.7 (4 patients with unstable angina). Untreated septal segments were used as controls. At 3 months, (n = 15 patients), the mean CCS angina class was to 2.43 +/- 0.9 (P < .05). On dobutamine echocardiography, the mean resting wall motion score index was improved by 16% in lased segments (P < .03 vs control), and mean LVEF at peak stress increased by 19% (P = NS vs baseline). On 201Tl-SPECT, perfusion of lased and nonlased segments did not change. On PET, the mean ratio of subendocardial to subepicardial perfusion (SEn/SEp) increased 14% over baseline (P < .001 vs control). At 6 months (n = 15 patients), the mean CCS angina class was 1.7 +/- 0.8 (P < .05). The mean resting wall motion score index was up by 13% in lased segments (P < .05 vs control). Resting LVEF was unchanged. Stress LVEF increased 21% (P = NS vs baseline). Myocardial perfusion remained unchanged by 201Tl-SPECT. On PET, 36% of the lased segments were better, and 25% were worse compared with baseline. The resting SEn/SEp by PET was up 21% (P < .001 vs control). All deaths (two perioperative and three late) occurred in patients with preoperative congestive heart failure. Two patients required repeat revascularization of new coronary lesions. CONCLUSIONS: These results suggest that TMLR improves anginal status, relative endocardial perfusion, and cardiac function in patients who do not have preoperative congestive heart failure.

Aged↗
PubMed1995

Overseas transport of a patient with an extracorporeal left ventricular assist device.

An 18-year-old boy with end-stage cardiomyopathy who was undergoing support with an extracorporeal pneumatic left ventricular assist device was transported from Japan to the United States. During the 17-hour flight, the patient's condition was stable, and the pneumatic assist device worked well under low atmospheric pressure in the cabin. Subsequently, he had a successful heart transplantation after 119 days of left ventricular assist device support.

Adolescent↗
PubMed1995

New technologies in the treatment of severe cardiac failure: the Texas Heart Institute experience.

Various mechanical alternatives for the treatment of severe cardiac failure are currently in clinical use, and new mechanical devices are under preclinical and clinical investigation in laboratories around the world. These devices include the intraaortic balloon pump, left heart bypass pumps, left ventricular assist devices, and total artificial hearts. I describe briefly the devices and their applications with which my colleagues and I at the Texas Heart Institute have had experience.

Cardiac Output, Low↗
PubMed1995

Improved mortality and rehabilitation of transplant candidates treated with a long-term implantable left ventricular assist system.

OBJECTIVE: This nonrandomized study using concurrent controls was performed to determine whether the HeartMate implantable pneumatic (IP) left ventricular assist system (LVAS) could provide sufficient hemodynamic support to allow rehabilitation of severely debilitated transplant candidates and to evaluate whether such support reduced mortality before and after transplantation. METHODS: Outcomes of 75 LVAS patients were compared with outcomes of 33 control patients (not treated with an LVAS) at 17 centers in the United States. All patients were transplant candidates who met the following hemodynamic criteria: pulmonary capillary wedge pressure > or = 20 mm Hg with a systolic blood pressure < or = 80 mm Hg or a cardiac index < or = 2.0 L/minute/m2. In addition, none of the patients met predetermined exclusion criteria. RESULTS: More LVAS patients than control patients survived to transplantation: 53 (71%) versus 12 (36%) (p = 0.001); and more LVAS patients were alive at 1 year: 48 (91%) versus 8 (67%) (p = 0.0001). The time to transplantation was longer in the group supported with the LVAS (average, 76 days; range, < 1-344 days) than in the control group (average, 12 days; range, 1-72 days). In the LVAS group, the average pump index (2.77 L/minute/m2) throughout support was 50% greater than the corresponding cardiac index (1.86 L/minute/m2) at implantation (p = 0.0001). In addition, 58% of LVAS patients with renal dysfunction survived, compared with 16% of the control patients (p < 0.001). CONCLUSIONS: The LVAS provided adequate hemodynamic support and was effective in rehabilitating patients based on improved renal, hepatic, and physical capacity assessments over time. In the LVAS group, pretransplant mortality decreased by 55%, and the probability of surviving 1 year after transplant was significantly greater than in the control group (90% vs. 67%, p = 0.03). Thus, the HeartMate IP LVAS proved safe and effective as a bridge to transplant and decreased the risk of death for patients waiting for transplantation.

Adolescent↗
PubMed1995

Separation of the natural atria in experimental implantation of total artificial heart.

Atrial connections in a single-unit total artificial heart (TAH) may be difficult to make because of the rigidity of the device and the fixed position of the atrial inlets. We developed a technique to separate the natural atrial borders in an experimental implantation of a unitary TAH. In this technique, the interatrial groove was dissected to separate the posterior wall of the right atrium from the roof of the left atrium before cardiopulmonary bypass (CPB) was initiated. After initiation of CPB and cardiectomy, the atrial septum was separated completely, and the right atrial wall was reconstructed with glutaraldehyde-treated autopericardium. We believe that this simple adjunctive technique provides increased mobility of the atrial cuffs and allows for an easier connection of the unitary TAH.

Animals↗
PubMed1995

Antifibrinolytic therapy in cardiac surgery.

Bleeding remains an important complication after repeat and complicated cardiac surgery. Although aprotinin has recently been approved by the Food and Drug Administration for use as an antifibrinolytic agent, many surgeons continue to have concerns about its added cost and potential side effects. We review here the current state of antifibrinolytic therapy for excessive bleeding in cardiothoracic surgery and suggest the use of a single intravenous dose of 10 g of epsilon-aminocaproic acid immediately before cardiopulmonary bypass as a safe, inexpensive, and effective alternative to aprotinin. Further clinical and laboratory studies are needed to confirm or modify this protocol.

Aminocaproic Acid↗
PubMed1995

Heart transplantation in an 8-month-old girl. 10th anniversary report.

In 1984, Dr. Denton A. Cooley led a surgical team that implanted a cardiac allograft in an 8-month-old girl who had end-stage cardiac disease secondary to endocardial fibroelastosis. At that time, experience with cardiac transplantation in infants was limited, and the long-term effects of the procedure were cause for concern. Ten years later, our patient is a healthy 4th-grade student who enjoys a remarkably normal life. She has grown and developed quite satisfactorily, and her heart has enlarged in proportion to her overall somatic growth. Long-term immunosuppression has produced no adverse effects, and the child's medical problems have differed little from those of her peers. This landmark case has yielded preliminary answers to a number of important questions about cardiac transplantation in infants and has confirmed our original opinion that the procedure is well warranted in selected patients.

Child↗
PubMed1995

Postpericardiotomy syndrome in pediatric heart transplant recipients. Immunologic characteristics.

Clinical features of postpericardiotomy syndrome (PPS) occur in pediatric heart transplant recipients despite immunosuppression, which raises questions about the mechanism of PPS. We studied the clinical and immunologic characteristics of 15 pediatric heart transplant patients, ages 1.1 to 17.8 years (mean, 7.5 years); 7 had clinical evidence of PPS (PPS+), and 8 were without clinical features of PPS (PPS-). Indicators of PPS included fever, irritability, pericardial friction rub, leukocytosis without other cause, and pericardial effusion. The onset of PPS was from 9 to 26 postoperative days (mean, 16 days). Immunosuppressive regimens were comparable up to the day of PPS diagnosis in PPS+ patients, and up to day 16 in PPS- patients (average onset of PPS in PPS+ patients). No differences were found between groups with respect to weight-adjusted dosages of cyclosporin A, azathioprine, or corticosteroids. Mean cyclosporin A levels in PPS+ and PPS- patients were 142 +/- 88 ng/mL (mean +/- standard deviation) and 265 +/- 122 ng/mL (p = 0.045), respectively. Echocardiographic data on 3 PPS+ patients within 1 day of PPS diagnosis revealed pericardial effusions ranging from 5 to 24 mm. No data were available on the remaining 4 PPS+ patients. Minimal pericardial effusions (< 10 mm) were seen in 4 PPS- patients during a comparable time period. One PPS- patient required pericardiocentesis. Endomyocardial biopsy rejection grade did not differ between groups. Means pretransplant soluble interleukin-2 receptor levels did not differ between PPS+ and PPS- patients (758 +/- 410 vs 653 +/- 270 IU/mL); nor did the PPS+ pretransplant levels differ from levels obtained 1 or 2 months postoperatively (700 +/- 437 and 751 +/- 367 IU/mL, respectively). Although pretransplant percentages of the standard T-cell (CD2, CD3, CD4, CD8) and B-cell (DR and CD19) markers differed from post-transplant values, the changes could be explained by the immunosuppressive regimen and did not differ between PPS+ and PPS- patients. In the PPS+ patients, however, there were significant increases in the proportion of activated helper T cells (CD4+/25+) and cytotoxic T cells (Leu-7+/CD8+) following heart transplantation in comparison with pretransplant levels. We speculate that these changes in activation marker in PPS+ patients suggest a possible role for cell-mediated immunity in the pathogenesis of PPS in this group of patients.

Adolescent↗
PubMed1995

Effect of IgM-positive crossmatches on survival in heart transplant recipients.

To determine whether an IgM-positive crossmatch adversely affects the results of heart transplantation, we conducted a retrospective study of 125 orthotopic heart transplant recipients. A direct donor-recipient crossmatch was performed retrospectively on sera from all patients by the standard National Institutes of Health (NIH) method and the antihuman globulin (AHG) procedure. The patients were then divided into 3 groups as follows. Group 1 comprised 110 patients with a negative NIH and AHG crossmatch (control group). Group 2 comprised 5 patients with a positive NIH crossmatch and a negative AHG crossmatch. Group 3 comprised 10 patients with positive NIH and AHG crossmatches. All positive crossmatches in group 3 patients converted to negative after treatment of sera with dithioerythritol, indicating that the initial result was due to IgM antibodies. All patients received standard immunosuppressive treatment. An IgM-positive crossmatch did not affect the number or severity of rejection episodes among the 3 groups, nor did it have an effect on the incidence of infection. Whereas coronary artery disease was detected by angiography in 16 of 110 patients (14.6%) in group 1 and in 1 of 10 patients (10%) in group 3 (P = NS), no patient in group 2 was affected. Actuarial survival at 1 and 2 years post-transplant was significantly better for patients with an IgM-positive crossmatch (group 2) (100% survival at 2 years) than for patients with a negative crossmatch (group 1) (73% at 1 year and 71% at 2 years, P < 0.05). Based on our study, the effect of an IgM-positive crossmatch on survival is difficult to interpret because of the small sample size. An IgM-positive crossmatch, however;did not appear to have a deleterious effect on survival. It may be that the IgM antibody has an immunoregulatory role. A larger series of patients with positive crossmatches and longer follow-up will be necessary to evaluate the importance of these results.

Actuarial Analysis↗
PubMed1995

Concomitant cardiac and pulmonary operations for lung cancer.

From 1973 through 1990, 21 patients (17 men and 4 women) underwent concomitant cardiac operation and pulmonary resection for lung cancer. The mean age was 65.3 years (range, 50 to 80 years). Eighteen patients underwent coronary artery bypass; 1 underwent coronary bypass and mitral valve replacement; 1, aortic valve replacement; and 1, left ventricular aneurysmectomy. Pulmonary procedures included 16 lobectomies, 3 segmentectomies, and 2 wedge resections. Nine resections were performed during cardiopulmonary bypass, and 12 were performed either before or after bypass. On final pathologic diagnosis, 11 patients had adenocarcinoma, 7 had squamous cell carcinoma, and 3 had undifferentiated lesions. Twelve patients were in cancer stage 1 and 9 were in stage II. Placement of an intraaortic balloon pump was required in 3 patients. No patient sustained excessive blood loss requiring reoperation. Only 2 incidents (9.5%) of disseminated infection were reported. The overall 1-year survival rate was 90.5% and the 5-year survival rate was 52.4%. We found concomitant cardiac operation and pulmonary resection for lung cancer to be a safe and effective alternative to staged treatment in patients not requiring a pneumonectomy. Combined cardiac and pulmonary surgery spares the patient the risk and cost of a 2nd major surgical procedure without compromising long-term survival.

Adenocarcinoma↗
PubMed1994

The relationship among donor-recipient HLA mismatches, rejection, and death from coronary artery disease in cardiac transplant recipients.

Review of 448 cyclosporine-treated heart transplant recipients was undertaken to examine the relationship of donor-recipient HLA compatibility to patient survival, rejection, and death from coronary artery disease (CAD). Pre-Tx crossmatching and panel-reactive antibody (PRA) were correlated to survival as well. Overall patient survivals were 78%, 70%, and 65% at 1,3, and 5 years post-Tx, respectively. Matching of donor-recipient HLA did not improve outcome in that 1,3, and 5 years survivals for well-matched (< or = 2 A, B, or 0-1 DR mismatches [MMs]) vs. poorly matched (> 2 A, B, or 2 DR MMs) recipients were comparable and not significantly different. Well-matched recipients, however, experienced significantly fewer rejections (1.06 +/- 1.2 vs. 1.96 +/- 1.0, P < 0.01 for < or = 2 A, BMMs vs. > 2 A, B MMs and 1.1 +/- 0.9 vs. 2.0 +/- 1.1 for 0-1 DR MMs vs. 2 DR MMs, P < 0.01). Moreover, HLA-DR, but not HLA A, B was a significant (P < 0.01) predictor of early rejection (<30 days) in that 65% (165/254) of poorly matched vs. only 40% (95/194) of well-matched HLA-DR recipients experienced early rejections. Interestingly, an inverse relationship was found between HLA A and B MM, but not HLA-DR MM, and death from coronary artery disease in that 17% (19/11) of well matched vs 9% (32/327) of poorly matched patients died from CAD. Pre-Tx PRA did not impact patient survival or rejection. Donor-recipient crossmatching was performed utilizing the NIH and/or antiglobulin (AHG) procedures. No survival differences were observed at 1, 2, and 3 years post-Tx when comparing outcome for the 24 NIH crossmatch (XM)-positive (+) with the 424 NIH-XM-negative displayed a positive AHG recipient antidonor displayed a positive AHG recipient antidonor reactivity. When these 10 AHG-XM (+) sera were treated with dithioerythritol (to inactivate IgM) all 10 converted to a negative reactivity, indicating that a positive crossmatch due to IgM reactivity should not be considered a contraindication to cardiac transplantation. These data also suggest that the reactivity of the 24 NIH-XM(+) sera were most likely due to IgM, and that poorly matched heart recipients may benefit from a more aggressive immunosuppressive regimen to prevent early rejections.

Adolescent↗
PubMed1994

Improved survival after extended bridge to cardiac transplantation.

In the past, left ventricular assist device (LVAD) support was frequently plagued by complications; thus, bridge to transplantation times were kept short. Increasing evidence suggests that extended bridging provides greater benefit due to improved end-organ perfusion and, thus, generally improved physical condition. To assess whether extended bridging translates into improved long-term survival after transplantation, we reviewed our experience with the HeartMate 1000 IP LVAD (Thermo Cardiosystems, Inc, Woburn, MA). Since January 1988, 19 patients (mean age, 45 +/- 9 years) have undergone extended bridging (mean time, 106 +/- 57 days). Their mean weight was 82 +/- 16 kg, and their mean body surface area was 2.0 +/- 0.2 m2. We define "extended" as the length of support necessary for systemic organ recovery after prolonged heart failure. During support, average pump flow indices ranged from 2.3 to 3.3 L.min-1.m-2, and all patients underwent physical rehabilitation. Between the time of LVAD implantation and explantation, the mean serum creatinine value decreased from 1.63 +/- 0.6 to 1.25 +/- 0.6 mg/dL (p = not significant), and the mean serum total bilirubin value decreased from 2.8 +/- 2.0 to 0.63 +/- 0.11 mg/dL (p < 0.05). All but 1 patient improved from New York Heart Association class IV to class I. Device-related complications were minimal. Twelve control patients ("de facto randomized") who did not receive the LVAD also were evaluated: actuarial survival at 1 year was 0% (p < 0.05); 3 (25%) underwent transplantation and died within 2 months; 9 (75%) died before transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Intermediate follow-up of pediatric heart transplant recipients with elevated pulmonary vascular resistance index.

OBJECTIVES: This study examined perioperative and intermediate outcomes in pediatric cardiac transplant recipients who had elevated pulmonary vascular resistance indexes preoperatively. BACKGROUND: Elevated pulmonary vascular resistance was associated with poor outcome in previous studies and constitutes a relative contraindication to transplantation. Few studies have evaluated this poor outcome risk factor in pediatric patients. METHODS: To evaluate outcomes of nonneonatal transplant recipients, records were reviewed and divided into Group I (preoperative pulmonary vascular resistance index > or = 6 units.m2) and Group II (pulmonary vascular resistance index < 6 units.m2). Donor/recipient weight ratios, ischemic times, length of intensive care unit stay, posttransplantation infection rates, arrhythmia, response to pretransplantation vasodilator infusions and pulmonary vascular resistance indexes at the first and most recent posttransplantation biopsies were analyzed. RESULTS: Group I (8 patients) had a mean (+/- SEM) pulmonary vascular resistance index of 11.5 +/- 3.5 units,m2; Group II (29 patients) had a mean pulmonary vascular resistance index of 2.3 +/- 0.4 units,m2 (p < 0.002). Pulmonary vascular resistance index decreased from 12.3 +/- 3.9 to 3.9 +/- 0.9 units.m2 (p < 0.05) in 7 Group I patients undergoing vasodilator infusion during pretransplantation catheterization. Thirty-six orthotopic heart transplantations were performed and one heterotopic transplantation. Donor weights exceeded recipient weights by 13% and 31% for Groups I and II, respectively (p > 0.25). Donor ischemic time was 215 min for Group I and 225 min for Group II (p > 0.75). Intensive care unit stay was 11.5 days in Group I and 15.1 days in Group II (p = 0.20). Infection rate was 38% in both groups (p > 0.80). Arrhythmias occurred in 90% of Group I and 42% in Group II (p < 0.03) patients. Pulmonary resistance index in Group I decreased from 11.5 +/- 3.5 to 3.3 +/- 1.2 units.m2 (p < 0.03) by the first posttransplantation biopsy and have not changed subsequently. During 2.3 years (range 0.3 to 8.5) of follow-up, the mortality rate was 25% and 21% for Groups I and II, respectively (p > 0.80). CONCLUSIONS: Group I patients did not require significantly oversized donors, restricted donor locations or longer intensive care unit stays or have higher infection rates; however, arrhythmias were more frequent. Pulmonary resistance index normalized early after transplantation. Pulmonary vascular reactivity may be more important for survival than absolute resistance index.

Adolescent↗
PubMed1994

Mechanical circulatory support in children.

Nine children (aged 1.2-15 years) have been treated with mechanical circulatory support devices at our institution. Indications for treatment were acute cardiac allograft rejection (n = 4), postcardiotomy cardiogenic shock (n = 4), and bridge to cardiac transplantation (n = 1). Eight patients required left ventricular support, and one required biventricular support. A BioMedicus centrifugal pump was used in eight patients, and a Hemopump intra-aortic axial flow device was used in one patient. In two patients, an intra-aortic balloon pump was in place at the time that circulatory support was instituted. Mechanical support time ranged from 2 to 139 h, and the average flow index was 2.31 l/min per m2. Three patients required hemodialysis during support, and one patient required re-exploration because of mediastinal hemorrhage. Recovery of native ventricular function was assessed by transthoracic or transesophageal echocardiography, and weaning from the device was achieved by gradually decreasing pump flow in increments of 0.1 to 0.5 l/min. Seven patients were successfully weaned from support. Two hospital deaths occurred after circulatory support had been discontinued: one patient died of respiratory failure and the other of gram-negative pneumonia and sepsis. The five surviving patients experienced no significant complications, and their hemodynamic indices were normal at the time of discharge. At a mean follow-up of 28.8 months, these patients are leading active unrestricted lives, with no long-term device-related sequelae. Based on this experience, mechanical circulatory support is feasible in children who experience profound circulatory failure from a variety of causes.

Adolescent↗
PubMed1994

First use of an untethered, vented electric left ventricular assist device for long-term support.

This report describes the first long-term (505-day) application of the vented electric (VE) HeartMate left ventricular assist device (LVAD) (Thermo Cardiosystems, Inc). The device consists of an abdominally placed, battery-powered titanium blood pump that, in contrast to earlier pneumatically powered systems, allows patients untethered freedom of movement. The batteries last 5 to 8 hours and can be changed on a rotating basis indefinitely. The patient, a 33-year-old man (90 kg, blood type O) with idiopathic cardiomyopathy, experienced end-organ heart failure (New York Heart Association [NYHA] class IV) while he was awaiting heart transplantation. When his hemodynamic criteria met those outlined in the protocol, we implanted the VE-LVAD as a bridge to transplantation. The patient was supported by the device for more than 16 months. His cardiac status returned to NYHA class I, and he was eventually allowed to take day trips outside the hospital as he awaited transplantation. The VE-LVAD enabled the patient to participate in activities such as eating in restaurants, going to movies, and practicing basketball shots. Unfortunately, the patient died suddenly due to a neurological thromboembolic event that occurred on day 503 of VE-LVAD support. The VE-LVAD improved native left ventricular function by chronic unloading, and ventricular remodeling resulted in a more normal configuration anatomically, physiologically, and ultimately, histologically and pathologically.

Adult↗