Enhancement of Toxic Substances Clearance from Blood Equvalent Solution and Human Whole Blood through High Flux Dialyzer by 1 MHz Ultrasound.

BACKGROUND: Hemodialysis is a process of removing waste and excess fluid from blood when kidneys cannot function efficiently. It often involves diverting blood to the filter of the dialysis machin to be cleared of toxic substances. Fouling of pores in dialysis membrane caused by adhesion of plasma protein and other toxins will reduce the efficacy of the filtre. OBJECTIVE: In This study, the influence of pulsed ultrasound waves on diffusion and the prevention of fouling in the filter membrane were investigated. MATERIAL AND METHODS: Pulsed ultrasound waves with frequency of 1 MHz at an intensity of 1 W/cm2 was applied to the high flux (PES 130) filter. Blood and blood equivalent solutions were passed through the filter in separate experimental setups. The amount of Creatinine, Urea and Inulin cleared from both blood equvalent solution and human whole blood passed through High Flux (PES 130) filter were measured in the presence and absence of ultrasound irradiation. Samples were taken from the outlet of the dialyzer every five minutes and the clearance of each constituent was calculated. RESULTS: Statistical analysis of the blood equvalent solution and whole blood indicated the clearance of Urea and Inulin in the presence of ultrasound increased (p<0.05), while no significant effects were observed for Creatinine. CONCLUSION: It may be concluded that ultrasound, as a mechanical force, can increase the rate of clearance of some toxins (such as middle and large molecules) in the hemodialysis process.

Successful treatment of a saphenous vein graft perforation with an autologous vein-covered stent.

A 52-year-old man with a history of prior coronary bypass surgery suffered recurrent angina and underwent percutaneous placement of a stent within the midportion of the saphenous vein graft to the marginal branch of the left circumflex coronary artery, which was complicated by a significant perforation. The perforation was successfully closed using an NIR stent covered with a segment of autologous antecubital vein. Subsequent surgical exploration confirmed successful closure of the perforation. Cathet. Cardiovasc. Intervent. 48:382-386, 1999.

Combined carotid endarterectomy and coronary artery bypass in a community hospital.

A study examining combined carotid endarterectomy and coronary artery bypass (CAB) outside the metropolitan or university hospital setting was performed. Over a 5-year period, 52 patients underwent carotid endarterectomy and CAB under a single anesthetic. Twenty-two patients (42%) had unstable angina and 23 (44%) had previous neurologic symptoms. There were two postoperative strokes (4%), one ipsilateral and one contralateral to the endarterectomy site. No ipsilateral neurologic events occurred after discharge (mean follow-up 25 months). There were four deaths (8%), all of which were cardiac related. Three of the four deaths were in patients with a recent history of congestive heart failure, a subgroup with a high mortality rate (three of seven; 43%). Over the same period, 2421 patients underwent CAB alone with stroke and mortality rates of 1.4 and 2.0% respectively, while 344 patients had carotid endarterectomy alone with stroke and mortality rates of 0.6 and 0.6% respectively. It is concluded that the combined procedure can be performed in a community setting with morbidity and mortality rates similar to those for major centers. Although stroke and mortality rates for the combined procedure were higher than those for the isolated operations, this group has a high incidence of cardiac symptoms, including unstable angina and congestive heart failure. Patients with recent congestive heart failure had the highest mortality rate of any subgroup and these patients should be carefully examined with regard to selection for the combined procedure.

Prevention of adult respiratory distress syndrome with plasminogen activator in pigs.

Death from traumatic shock has been associated with loss of blood externally or internally. However, many patients die after trauma, even though blood volume restoration is adequate. Death is often due to pulmonary failure (adult respiratory distress syndrome [ARDS]). Death and ARDS have been associated with disseminated intravascular coagulation (DIC) and microclots in the lungs. Dissolution of the microclots after trauma can be achieved by activation of endogenous plasmin. Nine pigs were anesthetized for 48 h. Trauma was administered by 60 standard blows to each thigh resulting in a bruise of muscle but no skin, bone, or major vessel injury. Nutrition and respiration were maintained at normal levels. All nine pigs died with severe lung pathology and low PaO2. Ten other traumatized pigs were treated with a plasminogen activator iv 4 h after trauma. Five of these were treated with tissue plasminogen activator (tPA) and five with urokinase. All treated pigs survived 48 h and maintained a normal PaO2. Autopsy showed minimal lung pathology.

Echocardiographic diagnosis and surgical treatment of postpartum pulmonary embolism.

Pulmonary embolism remains a problem in the United States in terms of both morbidity and mortality. New diagnostic modalities to make rapid diagnosis are now available, and allow for bedside diagnosis of pulmonary embolism without the use of pulmonary angiography. As a reference, a case involving a postpartum patient is reviewed. Use of echocardiography, a device readily available even in small institutions, allowed for early diagnosis and institution of therapy in this particular case and in others. Diagnostic features of pulmonary embolism are discussed and the literature is reviewed.

Blunt injuries to the aortic arch vessels.

Thirty patients with 33 vascular injuries from blunt trauma to the brachiocephalic branches of the aortic arch are reported. To our knowledge, this is the largest series reported to date of blunt injuries to these vessels. Mechanisms of injury included deceleration, traction, and crush. Half of the injured vessels were the innominate artery, and a quarter each were the common carotid and subclavian arteries. Common associated injuries were head injuries, hemopneumothorax, lung contusion, long bone fractures, and brachioplexus injuries. Widened mediastinum and extrapleural hematoma were common radiographic findings, and aortic rupture was frequently suspected. Angiography was performed in all patients to identify precisely the nature and site of the injury. Surgical approaches varied with the anatomical site of the injury and required consideration of vascular control in chest, neck, and upper extremity. Twenty-seven patients are alive 6 months to 10 years after injury. Eighteen of 20 vascular reconstructions were patent at follow-up. No patient with brachioplexus injury had return of neurological function.

Composite graft replacement of the ascending aorta and aortic valve. Late follow-up with intra-arterial digital subtraction angiography.

Between 1979 and 1986, 30 patients underwent replacement of the aortic valve and ascending aorta by a composite graft, with aortic wrapping of the graft. Thirteen patients had annuloaortic ectasia; six had DeBakey type I dissection (five acute, one chronic); three had DeBakey type II dissection (one acute, two chronic); three had left ventricular-aortic discontinuity caused by prosthetic valve endocarditis; three had sinus of Valsalva aneurysms after previous aortic valve procedures; and two had atherosclerotic aneurysms. Three patients died (10%). The mean duration of follow-up was 54 months. Fifteen patients consented to be restudied by intra-arterial digital subtraction angiography; studies were performed 6 to 58 months (mean 25 months) after composite graft replacement. Two patients had pseudoaneurysms at the right coronary anastomosis, which were repaired successfully. One patient showed persistent dissection beyond the distal aortic anastomosis; no reoperation has been done. One patient had pulmonary edema. Emergency study and reoperation showed disruption of the proximal aortic anastomosis and right coronary anastomosis. Anastomotic dehiscence after composite graft replacement is potentially lethal. Follow-up by means of intra-arterial digital subtraction angiography is simple and highly accurate. We suggest that dehiscences may occur early in the postoperative period and that restudy may be appropriate within a few months after operation.

Pulmonary hypertension in isolated aortic stenosis. Hemodynamic correlations and follow-up.

The clinical, hemodynamic, and angiographic data on 92 patients with severe isolated aortic stenosis were reviewed to determine the incidence and mechanism of pulmonary hypertension. The status of each of these patients was determined 1 to 8 years after diagnosis by cardiac catheterization. Patients were divided into three groups on the basis of the pulmonary artery systolic pressure: group 1 (less than or equal to 30 mm Hg), 46 patients; Group 2 (31 to 50 mm Hg), 31 patients; and Group 3 (greater than 50 mm Hg), 15 patients. The prevalence of pulmonary hypertension was 50% (46/92) and that of severe pulmonary hypertension, 16% (15/92). There was no significant difference in age, aortic valve gradient, or valve area among the three groups. There was a significant positive correlation in left ventricular end-diastolic pressure (group 1, 15.5 +/- 7.2 mm Hg; group 2, 23.3 +/- 8.1 mm Hg; and group 3, 29.5 +/- 5.8 mm Hg; R = 0.56, p less than 0.01). There was also a significant negative correlation in left ventricular ejection fraction (group 1, 67.5% +/- 14%; group 2, 62.3% +/- 13.8%; and group 3 49.9% +/- 18.3%; R = 0.43, p less than 0.01). Of the 92 patients, 85 had aortic valve replacement with four (4.7%) hospital deaths. Follow-up showed excellent symptomatic relief in all three groups. Thirteen of the 15 patients in group 3, with severe pulmonary hypertension, had aortic valve replacement. There were no hospital deaths and only one noncardiac death at follow-up in Group 3 patients, and 11 of the 12 surviving patients were in New York Heart Association functional class I. We conclude that pulmonary hypertension is common in isolated aortic stenosis and is related to an elevated left ventricular end-diastolic pressure, frequently with preserved systolic function. Surgical results are excellent.

Intravenous leiomyomatosis: a rare cause of right sided cardiac obstruction.

Intravenous leiomyomatosis involving the right side of the heart is an unusual cause of outflow obstruction. Evaluation of the patient should be directed not only at intracardiac chambers but also at the inferior vena cava. This should include angiography and MRI or CAT scanning. Echocardiography is an important contributory investigation. Surgical therapy should be directed at complete removal of the tumor as recurrence has been reported if a less than complete resection has been performed. Hormonal manipulation has been attempted with variable results.

Pulmonary hypertension in severe aortic stenosis. Incidence, mechanisms, clinical and surgical implications.

Pulmonary arterial hypertension in aortic stenosis (AS) is considered uncommon, and the possible mechanisms involved in its insorgence are only speculative. We analyzed a group of 95 patients with severe AS (mean systolic gradient greater than or equal to 50 mmHg and/or aortic valve area less than or equal to 0.7 cm2) studied by standard hemodynamic techniques. In the study group the incidence of pulmonary hypertension was 50.5%. We divided the overall population in: Group I (47 patients), with systolic pulmonary artery pressure (PAP) less than or equal to 30 mmHg; Group II (33 patients), with moderate hypertension (PAP 31-50 mmHg); Group III (15 patients), with severe hypertension (PAP greater than 50 mmHg). Subjects with pulmonary hypertension were slightly older, and had more severe obstruction to left ventricular (LV) outflow. Impairment of LV diastolic function in the presence of pulmonary hypertension was expressed by a highly significant increase of LV end-diastolic pressure (p less than .001); reduced ejection performance was represented by a significant decrease of ejection fraction (p less than .01). Pulmonary vascular resistances also appeared to be increased. The correlation between variables showed PAP to be strongly correlated in a positive way to the LV end-diastolic pressure, and in an inverse way to the LV systolic performance (p less than .001 for both). Less striking was the correlation of pulmonary vascular resistances to LV diastolic and systolic function: a reactive and reversible vasoconstriction seemed likely. Surgery was not performed in 8 of the 95 patients: 5 of them died shortly after diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Spinal cord ischemia following operation for traumatic aortic transection.

The danger of irreversible ischemic damage to the spinal cord following repair of traumatic aortic rupture has prompted many techniques designed to decrease this risk. Surgical repair was performed on 41 consecutive patients, using four different methods. These included: group 1 (15 patients), left-heart pump bypass with systemic administration of heparin; group 2 (7 patients), heparinized shunt from the ascending aorta to the descending aorta or to the femoral artery; group 3 (14 patients), heparinized shunt from the left ventricle to the aorta or femoral artery; group 4 (5 patients), aortic cross-clamp only. Spinal cord ischemia was not seen in groups 1 or 2, but paraparesis or paraplegia developed in 4 patients in group 3. Severe shock accompanied rupture in all patients in group 4, and no time was taken for a shunt or bypass. Four of the 7 deaths occurred in the operating room in patients who had arrived moribund and in severe shock. In our experience, shunts from the left ventricle to the aorta have failed to protect the spinal cord against ischemia. Left-heart bypass or aorta-to-aorta shunts are now our procedure of choice.

Rest and exercise hemodynamics following aortic valve replacement. A comparison between 19 and 21 mm Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves.

When aortic valve replacement is performed in a patient with a small anulus, significant obstruction of the left ventricular outflow tract may remain. Most prostheses are obstructive in the smaller sizes, and enlargement of the aortic anulus may be required to allow placement of a larger valve. To evaluate the hemodynamic performance of two commonly used tissue prostheses, the Ionescu-Shiley pericardial and Carpentier-Edwards porcine valves, 22 patients with either the 19 or 21 mm size were electively studied at rest and after exercise at a mean of 15 months after operation. The resting mean transvalvular gradient for 19 mm Ionescu-Shiley pericardial valves (n = 7), 10.6 +/- 9.2 mm Hg, was significantly lower than that for 19 mm Carpentier-Edwards valves (n = 3), 33.3 +/- 2.1 mm Hg, p less than 0.01. Following exercise, the mean gradient for 19 mm Ionescu-Shiley pericardial valves rose only to 13.8 +/- 8.5 mm Hg. No exercise data were available for the 19 mm Carpentier-Edwards valve. Among patients with 21 mm Ionescu-Shiley pericardial valves (n = 7), the mean transvalvular gradient at rest was 5.6 +/- 9.5 mm Hg, not significantly different from that of patients with 21 mm Carpentier-Edwards valves (n = 5), 9.8 +/- 18.3 mm Hg. After exercise, the gradients rose to 16.0 +/- 10.0 mm Hg and 25.5 +/- 23.8 mm Hg for the Ionescu-Shiley pericardial and Carpentier-Edwards valves, respectively (no statistical significance). Cardiac index was not different between groups. Gradients were not significantly higher in patients with body surface areas greater than 1.5 m2. It is concluded that the 19 and 21 mm Ionescu-Shiley pericardial valves possess excellent hemodynamics, even after exercise. This valve appears hemodynamically superior to the Carpentier-Edwards valve, particularly in the 19 mm size. Procedures to enlarge the aortic anulus are usually unnecessary when small Ionescu-Shiley pericardial valves are used, even in patients who have large body surface areas.

Primary osteosarcoma of left atrium: complete surgical excision.

A patient with primary osteogenic sarcoma of the left atrium with clinical features of severe congestive heart failure is described. The operative procedure required excision of the posterior atrial wall in continuity with the left pulmonary veins. The resultant defect in the atrium was reconstructed with the left atrial appendage. The left pulmonary artery was ligated, and the lung was removed at a subsequent procedure. The patient survived operation but subsequently was found to have distant metastasis. He died seven months after the operation.

Neurologic complication following coronary artery bypass. The role of atherosclerotic emboli.

Neurologic complications continue to plague aortocoronary bypass operations. All patients undergoing isolated coronary artery bypass procedures over a four-year period at the Upstate Medical Center were reviewed. Eight of 893 patients sustained a cerebrovascular accident following operation (0.9%). In 5 patients, the etiology was felt to be calcific and atherosclerotic debris from the ascending aorta. Air embolism occurred in one patient, and the etiology was unknown in 2 patients. Various methods to deal with the diffusely atherosclerotic aorta are discussed.

Injuries to arterial branches of the aortic arch.

Exposure of arch branches for repair following trauma can be difficult. Seven patients with blunt injuries and 5 with penetrating injuries underwent repair of the innominate, common carotid and subclavian arteries. Common associated injuries included head injury, hemopneumothorax, lung contusion, long bone fractures and brachial plexus injury. Widened mediastinum was seen in 5 patients. Six patients with innominate, right subclavian and right common carotid injuries were approached through sternotomy with extension into the right side of the neck. Posterolateral thoracotomy was used to reach the proximal left subclavian artery in 2. Combined supra- and infraclavicular incision were utilized for the distal subclavian artery in 4. Eleven patients are alive, one to 7 years after surgery. One died of an unrelated cause. Head injuries complicated the postoperative management in 4 of the 7 patients with blunt trauma. Two patients with brachial plexus injury continued to have neurologic deficits. All arterial repairs have remained patent and there have been no graft infections.

Approach in the management of atrial myxoma with long-term follow-up.

Between 1972 and 1982, 9 patients underwent successful excision of atrial myxomas at the Upstate Medical Center. Eight patients had a left atrial myxoma and 1 a biatrial myxoma. There were 5 female and 4 male patients ranging from 16 to 63 years of age. Preoperative findings consisted of cerebral or peripheral emboli, congestive heart failure, and nonspecific symptoms. Diagnosis was confirmed by echocardiography and angiography in all but 1 patient. A biatrial operative approach was utilized in all patients except 1. Complete excision of the tumor with a cuff of normal tissue was performed. All heart chambers were carefully explored for presence of multicentric myxomas or tumor debris. There were no operative deaths or intraoperative embolizations. Follow-up has been 1 1/2 to 11 years. There has been 1 late noncardiac death. All patients underwent echocardiography postoperatively with no recurrence. The risk of intraoperative embolization and late recurrence is minimal with the biatriotomy technique. Two-dimensional echocardiography is extremely accurate in early diagnosis of myxomas and in the late follow-up of patients.

Complete extra-anatomic bypass of the aortic root: treatment of recurrent mediastinal infection.

A 45-year-old woman underwent complete extra-anatomic bypass of the aortic root for recurrent mediastinal infection. Operative repair consisted of removal of an aortic valve prosthesis and an ascending aortic graft. The aortic root and transverse aortic arch were closed primarily and a valved conduit was placed from the left ventricular apex to the descending aorta. Coronary flow was reestablished with saphenous vein grafts taken from the innominate and subclavian arteries to the coronary artery orifices. Infection did not recur, but the patient died 9 months following operation apparently of right coronary artery graft occlusion.

Supraventricular arrhythmias following coronary artery bypass. The effect of preoperative digitalis.

Supraventricular arrhythmias continue to complicate the postoperative course of patients undergoing myocardial revascularization. In a previous study, we showed a decrease in arrhythmias if patients were given digitalis prior to operation. Since that time we have made two changes-- propranolol is no longer discontinued prior to operation and cold hyperkalemic cardioplegic solution is routinely used. To assess the affect of these changes on arrhythmias, we repeated the previous study. One hundred twenty patients all receiving preoperative and postoperative propranolol were randomized into a control group and a digitalis-treated group. The incidence of supraventricular arrhythmia postoperatively was 21.4% in the control group and 3.1% in the digitalis group (p less than 0.005). Therefore, we continue to advise preoperative digitalization in patients requiring coronary artery bypass and continue to maintain beta blocker and digitalis therapy in the postoperative period.