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Biomedical subjects

J M Armitage

Publications and source records attributed to J M Armitage.

At least 73 records · Page 4Linked to original sources
PubMed1990

Clinical experience with the Medtronic-Hall valve prosthesis.

Medtronic-Hall valves were implanted during 204 procedures performed between 1982 and 1988. Mean population age was 54.4 years; 96% of patients were in New York Heart Association functional class III or greater. Emergency operations constituted 16% of the procedures. Rheumatic heart disease was the single most common indication for valve replacement. In 18% of patients, operation was performed to replace a previous prosthetic valve. The mean follow-up was 3.2 years. Overall operative mortality was 10.3%, the highest mortality being for double-valve replacements (24%). Valve-related mortality, by position, was 5.3% for aortic valves, 6.0% for mitral valves, and 4.0% for multiple-valve replacements. Actuarial 5-year freedom from events were: survival, 68%; thromboembolism, 90%; prosthetic valve endocarditis, 98%; paravalvular leak, 95%; and reoperation, 92%. Complications with the highest mortality were thromboembolism (36%) and endocarditis (33%). The complication rates in this series are high but the patients were more severely ill than in other reports, and operative survivors experienced a considerable improvement in New York Heart Association functional class.

Aortic Valve↗
PubMed1990

Acute myocardial dysfunction and recovery: a common occurrence after coronary bypass surgery.

To evaluate whether acute myocardial dysfunction was common in the early postoperative period, serial hemodynamic measurements and radionuclide evaluation of ventricular function were performed before and after operation in 24 patients undergoing elective coronary bypass surgery. All patients had uncomplicated surgery, and no patient sustained an intraoperative infarction. In 96% of patients, significant depression in right and left ventricular ejection fraction was seen postoperatively, reaching a nadir at 262 +/- 116 min after coronary bypass. Left ventricular ejection fraction was 58 +/- 12% preoperatively and 37 +/- 10% at trough. Right ventricular function displayed a similar pattern. These findings were also associated with depressed cardiac and left ventricular stroke work index despite maintenance of adequate ventricular filling pressures and mean arterial pressure. The depression in ventricular function was partially reversible within 8 to 10 h after surgery. Left ventricular ejection fraction had increased to 55 +/- 13% at 426 +/- 77 min after coronary bypass and showed complete recovery within 48 h. Left ventricular end-systolic and end-diastolic volume index increased significantly postoperatively, but recovery in left ventricular ejection fraction was mostly due to decreases in end-systolic volume index (50 +/- 22 ml at trough and 32 +/- 16 ml at recovery). Depressed myocardial function was independent of bypass time, number of grafts placed, preoperative medications or core temperatures postoperatively. Postoperative therapy with pressors or inotropic agents delayed but did not prevent the occurrence of postoperative ventricular dysfunction. Despite improvements in operative techniques and methods of myocardial protection, postoperative left ventricular dysfunction continues to be common in patients undergoing cardiopulmonary bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Heart transplantation in diabetic recipients.

Preexisting diabetes mellitus (DM) has been regarded as a contraindication to heart transplantation (HT). This prejudice has been based upon concern over increased infection rates and worsening DM with the initiation of prednisone immunosuppression. To better evaluate these suppositions, we reviewed our experience with diabetic patients who underwent HT. Between 6/80 and 1/88, 367 nondiabetics (NDs) and 19 diabetics underwent HT at our institution. Of the 19 diabetic recipients (DRs), two were black and four were female. Six DRs were on insulin (average daily dose: 46 U) prior to HT, and the remainder required oral hypoglycemic agents. Following HT, five DRs had insulin substituted for oral hypoglycemics. The 11 insulin-dependent DRs now require an average daily dose of 48 U. The average duration of follow-up for the 19 DRs was 17 months (range 1-67 months). During this time, 5 hospitalizations were required for complications of diabetes. The rejection rate was not higher for the DRs than the NDs (0.37 events/100 pt. days vs. 0.51 events/100 pt. days). The DRs who have undergone coronary angiography up to 4 years following HT have had no evidence of coronary atherosclerosis. Three-year survival for DRs and NDs is similar. DRs have a slightly higher incidence of lethal infections than NDs, which is not statistically significant (16% at 17 months vs. 10% (p greater than 0.4). We conclude that carefully selected diabetics can undergo HT with minimal consequent worsening of their DM. Diabetic HT recipients do not suffer a higher incidence of graft atherosclerosis, rejection, or lethal infection.

Coronary Disease↗
PubMed1990

Optimal perioperative immunosuppression in cardiac transplantation using rabbit antithymocyte globulin.

A randomized trial of RATG (polyclonal) vs. OKT3 (monoclonal) antibody prophylaxis was carried out in 82 cardiac transplant recipients who, in addition, received baseline immunosuppression with cyclosporine, azathioprine and prednisone. One-year actuarial survival was comparable between groups (95% and 98%). The incidence of moderate or severe rejection within the first 30 days of transplant was over 7 times greater in patients receiving OKT3 vs. those receiving RATG. Patients receiving OKT3 were more likely to have repeated episodes of rejection and the mean time to rejection for patients receiving OKT3 was shorter (33 days) than for RATG patients (67 days). At 120 days, 52% of RATG patients were free of rejection while only 37% of the OKT3 patients were rejection-free. There was no difference in the incidence of major or minor bacterial or viral infection between groups. Patients receiving OKT3 showed a less-prolonged depression of the CD3 and CD4 T cell subsets than did those receiving RATG. Significant hemodynamic side-effects were seen after the first dose of OKT3 and there was a 5% incidence of aseptic meningitis associated with its use.

Antibodies, Monoclonal↗
PubMed1990

Hemodynamic parameters influencing clinical performance of Novacor left ventricular assist system.

The interrelationships between hemodynamic variables including right ventricular (RV) performance with filling/ejection dynamics of the Novacor left ventricular assist system (LVAS) were determined in 10 of 11 patients who received LVAS as a bridge to heart transplant. Nine were successfully transplanted. Data were obtained intraoperatively, at periodic intervals up to 48 h postimplant and at explant. The hypotheses investigated included (a) RV performance influences LVAS filling characteristics and (b) LVAS pump output is influenced by systemic vascular resistance (SVR). During the period of LVAS support (2-126 days), pumping characteristics included a mean filling volume of 51 ml (range, 24-70), residual volume of 4.9 ml (range, 1-18), pump rate of 113/min (range, 63-175), and pump output of 5.81/min (range, 2.8-8.2). Multiple regression analysis identified pulmonary vascular resistance (PVR), RV stroke work index (RVSWI), and pulmonary capillary wedge pressure, but not RV ejection fraction, pulmonary artery pressure, or central venous pressure (CVP) as the most important correlates with LVAS filling volume (p less than 0.001, R2 = 0.6). In addition, LVAS pump output was influenced mainly by RVSWI, PVR, and SVR (p less than 0.001, R2 = 0.7). It was concluded that LVAS performance is highly dependent on RV function and systemic/pulmonary vascular resistances.

Equipment Design↗
PubMed1990

Ear involvement in the yellow nail syndrome.

Recognized features of the yellow nail syndrome include yellow nails, lymphedema, and pleural effusions. We report a patient with the additional feature of keratosis obturans, which may be a manifestation of this syndrome in the external ear.

Ear Canal↗
PubMed1990

Bradyarrhythmia after heart transplantation. Incidence, time course, and outcome.

From June 1980 to April 1989, 72 of 401 (18%) adult recipients of orthotopic heart transplantation developed prolonged (greater than 24 hours) bradyarrhythmias (less than 60 beats/min) within 5 days after transplantation. Junctional bradycardia occurred in 50 (69%) recipients, sinus bradycardia in 18 (25%), and slow ventricular response during atrial fibrillation in four (6%). Fifty-five of 72 (76%) patients had bradyarrhythmias of less than 20 days' duration (less than 7 days, 50 patients; 7-20 days, five patients). Fifty patients returned to sinus rhythm (greater than 60 beats/min) by the time of discharge. Five patients expired within 20 days. Seventeen of 72 (24%) patients had bradyarrhythmia for more than 20 days, which was symptomatic in 11. All 17 patients (junctional bradycardia, 13 patients; sinus bradycardia, four patients) received a permanent pacemaker within 40 days after transplantation. Between 1 and 12 months (mean, 4 +/- 3 months) after pacemaker implantation, 12 patients recovered sinus rhythm (greater than 70 beats/min). The other five patients had intrinsic rates of 32-57 beats/min (mean, 48 +/- 10 beats/min) during 1-9 months (mean, 4 +/- 3 months) of follow-up. The donor ischemic time in bradyarrhythmia patients was 202 +/- 34 minutes, which was significantly longer (p less than 0.01) than the 173 +/- 43 minutes for those patients without bradyarrhythmia. Conclusively, the incidence of posttransplantation bradyarrhythmia is relatively high. It is usually temporary, however, even in patients with a prolonged duration of bradyarrhythmia. A relation appears to exist between donor ischemic time and the incidence of bradyarrhythmia.

Adult↗
PubMed1989

The value of protective isolation procedures in cardiac allograft recipients.

The impact of protective isolation on the incidence of infection in 60 cardiac transplant recipients (mean age, 49.2 years) was studied in a prospective randomized trial. Thirty patients were randomized to protective isolation, which consisted of private room, hat, mask, sterile gown, and handwashing. Thirty patients were randomized to no isolation, which meant they recovered in a crowded, open intensive care unit and were adjacent to recipients of liver transplants or patients who were on the trauma, neurosurgical, and general surgical services, many of whom had an infection of the incision or a pulmonary infection. There was no difference between groups in the proportion of patients in whom infection developed (chi 2[1] = 0.27; p = 0.6), the number of infection-related deaths (2 in each group), the types of infection (bacterial, viral, fungal, or protozoal), or the overall outcome. Because protective isolation offered no benefit over standard care in protecting these patients from infections or the associated complications, we have discontinued its routine use after cardiac transplantation.

Adolescent↗
PubMed1989

Organ procurement for pulmonary transplantation.

Selection of suitable donors is critical to the success of clinical pulmonary transplantation. Requirements for lung donors, management before explantation, and methods of preservation were reviewed for the 70 heart-lung, eight double-lung, and two single-lung transplantations performed at the University of Pittsburgh since 1982. Careful observation of trends of hyperoxygenation studies, chest roentgenograms, and Gram stain and culture results of tracheal secretions, as well as findings on bronchoscopy, can help identify which lungs not only have adequate function but are acceptable for transplantation. In spite of the rigid criteria used, 76% of tracheal cultures from donors deemed acceptable grew organisms. The presence of oropharyngeal flora has been shown to correlate with the development of early intrathoracic infections in the recipient. Prophylactic broad-spectrum antibiotic treatment of the donor is desirable to treat microbial contamination that could cause focal injury to the donor lung and predispose to infection in the recipient. Acceptance of less than ideal donors is ill-advised even though rejection of such donors conflicts with the current shortage of organs.

Graft Survival↗
PubMed1989

Infections in mortally ill cardiac transplant recipients.

A total of 351 cardiac transplantations performed between June 1, 1980, and Sept. 30, 1987, were reviewed to determine if infectious complications were more frequent in those patients requiring preoperative intravenous inotropic support, placement of an intraaortic balloon pump, or mechanical support with a left ventricular assist device or total artificial heart. One hundred forty-nine transplants (45%) were performed in these mortally ill patients. There was no statistically significant difference between patients with and without infection within each support group for the following: the number of in-patient days awaiting a donor heart, the number of days receiving support, the percent of patients with preoperative tracheal intubation, the length of the operation, and the percent of patients requiring reoperation for bleeding. The need for invasive methods of support (intraaortic balloon pump, left ventricular assist device, or total artificial heart) in patients awaiting heart transplantation increases the prevalence of perioperative nonviral infection. Preoperative mechanical support with a left ventricular assist device or total artificial heart significantly increases the risk of infection-related mortality.

Adult↗
PubMed1988

The artificial heart: infection-related morbidity and its effect on transplantation.

Between October, 1985, and September, 1987, a total of 195 patients received cardiac allografts and 15 candidates required mechanical support with the Jarvik-7 total artificial heart. Seven of the 15 died within 60 days of total artificial heart implant. There have been no late deaths, and survivors are unrestricted. Six of 7 deaths were related to infection (mediastinitis, 5; pneumonia and sepsis, 1), and the remaining 1 was due to failure of the transplanted heart. Respiratory tract infection occurred in each of the recipients who died with infection, and the same organisms appeared to be related to subsequent mediastinitis in 3 patients (Serratia marcescens, 2; Pseudomonas, 1) and caused fatal sepsis in another (Enterobacter aerogenes, Candida albicans). One patient died with pneumonia and sepsis prior to transplantation, and another succumbed with mediastinal infection known to be present before transplantation.

Heart Transplantation↗
PubMed1985

Septic complications of corticosteroid administration after central nervous system trauma.

The records of 197 consecutive multiple trauma patients were reviewed to define the infectious complications of corticosteroids used to treat brain and spinal cord injury. An injury severity score (ISS) and a central nervous system (CNS) injury score were determined for each patient. Patients with an ISS less than 20 did well with or without steroids and were excluded from further study. All deaths that occurred 5 or more days after injury were caused by sepsis, and all occurred in steroid recipients. Twenty-nine of 61 steroid-treated early survivors developed infectious complications, compared to eight of 55 patients who did not receive steroids (47.5% vs. 14.5%, p less than 0.001). There was no correlation between severity of CNS trauma and infectious complication rate. Steroid-treated patients frequently developed multiple pathogen primary infections and multiple, simultaneous septic foci. Patients treated with steroids more often developed infections caused by Staphylococcus aureus, assorted gram negative rods, anerobic bacteria, or fungi. The study strongly suggests a significant increase in both the incidence and severity of infectious complications occurring in patients treated with corticosteroids for CNS trauma.

Adolescent↗
PubMedDate not supplied

Acquired right ventricular outflow tract obstruction after lung transplantation: diagnosis by transesophageal echocardiography.

Acute reduction in pulmonary pressures after lung transplantation for severe chronic pulmonary hypertension may produce a sudden decrease in cavity size of a hypertrophied right ventricle resulting in acquired right ventricular outflow tract obstruction. This case illustrates the utility of transesophageal echocardiography with continuous-wave Doppler to make a morphologic as well as hemodynamic diagnosis of acquired right ventricular outflow tract obstruction in a patient after lung transplantation.

Echocardiography↗
PubMedDate not supplied

Evaluation of right ventricular function during clinical left ventricular assistance.

Hemodynamic and mechanical parameters of right ventricular (RV) performance were measured in eight patients undergoing left ventricular (LV) assistance as a bridge to cardiac transplantation. All patients, even those with impaired RV performance, survived support and transplantation. The reduction of LV afterload produced by the left ventricular assist system (LVAS) results in RV afterload reduction, which permits even the marginal RV to function adequately during LVAS support.

Adult↗
PubMedDate not supplied

Differential regional function of the right ventricle during the use of a left ventricular assist device.

The use of a left ventricular assist device (LVAD) as a bridge to transplant is associated with a 52% incidence of RV failure requiring additional inotropic or mechanical support (RVAD). This study evaluated the differential performance of the RV free wall and septum to identify the need for additional RV support. Cross-sectional views of the RV were obtained immediately before, and 1 hr after, Novacor LVAS implantation in 12 consecutive patients using transesophageal echocardiography. Each image was divided into a free wall portion (FW) and a septal portion (SP) by grids drawn from the center of gravity of the end-diastolic endocardial outline to the junction between the FW and the SP. Percentage change between preimplant and postimplant for RV ejection fraction (RVEF), fractional area change for the FW (FAC-FW) and the SP (FAC-SP), and fractional shortening of the FW to SP distance (F-S) is reported for patients based upon the need for RV support: minimal (Group 1), maximal (Group 2). After LVAS implantation, patients showed a reduction in SP fractional area change. However, this reduction was most pronounced in Group 2. The degree of SP impairment may explain the mechanism of RV failure in patients on an LVAD.

Adolescent↗
PubMedDate not supplied

Utility of prostaglandin E1 in the pretransplantation evaluation of heart failure patients with significant pulmonary hypertension.

Patients with chronic heart failure frequently have pulmonary hypertension. Because severe preoperative pulmonary hypertension predicts a poor outcome after orthotopic transplantation, pulmonary vasoreactivity is evaluated frequently in the pretransplantation screening of heart failure patients. We prospectively evaluated the utility of the direct pulmonary vasodilator, prostaglandin E1, and compared it to the nonspecific vasodilators, nitroglycerin and sodium nitroprusside, in the evaluation of pulmonary hypertension in 39 heart transplantation candidates. Prostaglandin E1 significantly lowered pulmonary artery pressure, transpulmonary pressure gradient, and pulmonary vascular resistance. An adequate pulmonary vasodilator response (defined as a decline in transpulmonary pressure gradient to less than 15 mm Hg) occurred in 31 patients (79%). In a subgroup of nine patients also tested with nitroglycerin, greater reductions (p less than 0.01) in both transpulmonary pressure gradient and pulmonary vascular resistance occurred with prostaglandin E1, compared to nitroglycerin. Five of six patients who did not respond to nitroglycerin responded to prostaglandin E1. In another subgroup of 12 patients who were also evaluated with sodium nitroprusside, prostaglandin E1 produced a larger decline (p less than 0.05) in transpulmonary pressure gradient and pulmonary vascular resistance than did sodium nitroprusside. Six of eight patients who did not respond to sodium nitroprusside responded to prostaglandin E1. Based on pulmonary vasodilator response to prostaglandin E1, 27 patients were accepted on the transplantation waiting list, and eight patients underwent orthotopic transplantation. Postoperatively, acute right ventricular failure of the donor heart developed in none of these patients. Significant hemodynamic improvement occurred by 24 hours and persisted through 4 weeks of postoperative follow-up in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗