Clinical Experience with BioMedicus Centrifugal Ventricular Support in 172 Patients

Abstract: One hundred and seventy-two patients at The Methodist Hospital in Houston, Texas, were placed on BioMedicus centrifugal ventricular support. One hundred thirty-nine patients were male and 33 were female with a mean age of 59.7 years. Reasons for support were post-cardiotomy cardiac failure (129 patients), cardiac allograft failure (17 patients), bridge to transplantation (10 patients), resuscitation (7 patients), postpercutaneous trans-luminal coronary angioplasty emergent (2 patients), and other (7 patients). Support was by left ventricular assist device in 108 patients, right ventricular assist device in 20 patients, and biventricular assist device in 44 patients. Eighty-four patients (48.8%) were weaned from the ventricular assist device, and 88 patients (51.2%) were not weaned. Thirty-four patients (20.0%) were discharged from the hospital. Complications included coagulopathy, renal insufficiency/failure, respiratory insufficiency/ failure, neurological deficits, sepsis, arrhythmias, and device-related complications. Overall causes of death were ventricular failure (55.1%), triage (13.0%), arrhythmias (9.4%), graft failure (5.9%), coagulopathy (4.3%), sepsis syndrome (2.9%), device-related (0.7%), and other (0.7%). BioMedicus centrifugal ventricular support can be implemented rapidly and easily. Device-related complications are few (1.2%), and it is relatively inexpensive when compared with other ventricular assist systems. This series demonstrates that a substantial number of patients may benefit from temporary centrifugal ventricular support.     

Factors that influence the assessment of parathyroid graft function

Autogenous parathyroid grafts are used in the treatment of primary and secondary parathyroid hyperplasia and for salvaging normal parathyroid glands removed during thyroid surgery. Placement of the autogenous grafts in the forearm may allow assessment of graft function by comparing the patient's background level of immunoreactive parathyroid hormone (iPTH) with the iPTH value in the antecubital vein above the parathyroid graft. Among patients who on clinical grounds seem to have functioning parathyroid tissue, significant iPTH gradients can be demonstrated in only approximately 80%. Several technical and clinical factors can prevent demonstration of an iPTH gradient in patients who in fact do have functioning parathyroid grafts. Hypercalcemia may suppress iPTH secretion. PTH secretion may be intermittent. High background levels of iPTH due to renal failure may transform a significant numerical gradient for iPTH into an insignificant percentage change in iPTH. It may be technically difficult to obtain blood from the particular vein bearing effluent from the parathyroid graft. The regional specificity of the iPTH assay employed may have an important influence on the magnitude of the apparent iPTH gradient. Knowledge of these factors should maximize the chance of documenting parathyroid graft function.     

Particulate Microembolism During Cardiac Operation

In order to quantitate particulate microembolism during cardiac operations, particles 13 to 80 μ in size were measured, with a particle size analyzer, in the blood of patients before and during cardiopulmonary bypass. Venous particle measurements did not change. The volume of particles in arterial blood drawn from the bubble oxygenator (41.3 ± 4.4 × 10³ μ³/mm.³, mean ± SE) was greater than that in venous blood (30.7 ± 4.1 × 10³ μ³/mm.³1987, p < 0.05) only during the first 10 minutes on bypass. In contrast, the volume of particles in blood drawn from the cardiotomy return line was markedly elevated (903 ± 121 × 10³ μ³/mm.³). These microemboli remained elevated throughout the procedure, were most evident when extravasated blood was collected with the coronary suction line, and had a size distribution similar to platelet aggregates which could be induced in vitro in the patient's blood. The microemboli differed from platelet aggregates in that they were more resistant to deaggregation in vitro and a greater percentage (17%) floated into plasma after centrifugation. A Dacron wool filter removed 89% of these microemboli, while a 40 μ pore mesh filter and a polyurethane foam filter removed 58 and 64%, respectively. The data thus indicate that Dacron wool filtration of blood infused through the cardiotomy system would virtually eliminate particulate microembolism during cardiopulmonary bypass.     

Aneurysms of the extracranial carotid artery. Twenty-one years' experience.

Aneurysms of the extracranial carotid artery are an uncommon but potentially serious problem, usually due to rupture or thromboembolic events. Thirty-seven aneurysms of the extracranial carotid artery were seen in thirty-four patients from 1956 to 1977. The ages ranged from twenty-nine to ninety-two years, with an average of fifty-nine years. There were twenty-three males and eleven females. Nineteen (51 per cent) were false aneurysms, sixteen (44 per cent) atherosclerotic aneurysms, and two (5 per cent) posttraumatic aneurysms. All patients presented with evidence of a mass in the neck, and only five (15 per cent) had neurological symptoms related to the aneurysm. Surgery was performed on twenty-eight carotid aneurysms. Resection and patch angioplasty was employed for eighteen aneurysms, resection with graft replacement for six, and resection and ligation of the internal carotid artery for four. Postoperative neurologic deficits developed in three patients (11 per cent), and one of these died. There was one other operative death due to acute myocardial infarction (operative mortality, 7 per cent). Nonoperative treatment was employed when the patient had other associated high risk disease or a small asymptomatic aneurysm.     

Delayed diagnosis of injuries to the diaphragm after penetrating wounds

During a 9-year period, 16 patients with a delay in diagnosis of an injury to the diaphragm after a penetrating wound were treated. The left hemidiaphragm was involved in 15 of 16 patients, and the delay in diagnosis from the time of arrival in the emergency center immediately after injury ranged from 16 hours to 14 years. In the patients in the Acute Group (delay of hours to days), three patients had diaphragmatic defects missed at the time of laparotomy, three patients had chest X-rays not immediately suggestive of diaphragmatic defects, two patients had false-negative lavages, and one patient treated elsewhere did not have a chest X-ray in the emergency room. In the patients in the Chronic Group (hernias presenting months to years after injury), four of seven patients had misreading of a recent chest X-ray or failure to have a chest X-ray performed during numerous return visits to the emergency center. Despite a variety of diagnostic maneuvers, these defects and hernias continue to be diagnosed after a delay. Careful review of early and late followup chest X-rays appears to be the easiest mechanism to avoid significant delays in diagnosis.     

Urinary melatonin excretion throughout the ovarian cycle in menstrually related migraine

Nocturnal urinary melatonin excretion was significantly decreased throughout an ovarian cycle in 12 migraine without aura patients compared to 8 healthy controls. Normal increases in urinary melatonin excretion during the luteal phase was less pronounced in the migraine patients. Melatonin excretion was further decreased during headache. The data indicate impaired pineal function in migraine.     

In Vitro Evaluation of U. S. and U. S. S. R. Artificial Hearts

This report summarizes the results of the in vitro evaluation of Soviet and American artificial hearts. The devices were tested at the All-Union Institute of Transplantation and Artificial Organs, Moscow, U.S.S.R., and Baylor College of Medicine, Houston, Texas, U. S. A. These studies were designed to standardize procedures to allow comparison of artificial ventricles of different designs. Also, these studies might provide a means for evaluation of other characteristics such as hemolysis, durability, and reliability. Static and dynamic tests were performed, varying preload, afterload, rate, and systolic and diastolic time intervals. All designs demonstrated comparable function curves with capability of taking over the pressure and volume work of the natural heart.