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Biomedical subjects

H A Berkoff

Publications and source records attributed to H A Berkoff.

At least 19 recordsLinked to original sources
PubMed1995

Advantages of continuous noncardioplegic warm blood retrograde perfusion over antegrade perfusion during proximal coronary anastomoses.

Retrograde perfusion via the coronary sinus supplies vascular beds distal to coronary stenoses and has been used for administration of cardioplegia. An additional application is to supply noncardioplegic retrograde perfusion while performing proximal anastomoses (a time when cardiac arrest is not critical). The aim of this study was to determine the safety of this technique and to study the metabolic changes with antegrade versus retrograde warm blood perfusion. Sixty-six patients, with good left ventricular function, underwent distal coronary bypass in a similar fashion. Proximal anastomoses were done with 1) partial occlusion clamp (n = 29) or 2) cross-clamp on and continuous, warm, noncardioplegic retrograde blood perfusion (n = 37). In an additional 10 patients, metabolism was assessed with antegrade and retrograde perfusion during proximal anastomoses. Despite longer cross-clamp times (96.4 +/- 6.2 vs 80.8 +/- 3.1 min, p < 0.05) with retrograde perfusion, the total duration of cardiopulmonary bypass was significantly less (119.6 +/- 6.2 vs 136.6 +/- 4.6 min, p < 0.05). There was superior postbypass, intraoperative hemodynamics (cardiac index) with retrograde perfusion (4.0 +/- 0.2 vs 3.6 +/- 0.1 L/min/m2). The incidence of postoperative dysrhythmia was not significantly different between groups. Oxygen and glucose utilization was more efficient with retrograde perfusion. Retrograde perfusion during proximal anastomoses is a safe technique. There is diminished risk of aortic dissection, atheroembolism, delayed aneurysm formation, or rupture due to avoidance of application of partial occlusion clamps. There is evidence of superior substrate utilization.

Aged↗
PubMed1994

Use of Carmeda-coated femoral-femoral bypass during repair of traumatic aortic pseudoaneurysms.

OBJECTIVE: To compare the results and outcomes of three different approaches to posttraumatic pseudoaneurysm repair: clamp and sew, left heart bypass, and the most recent approach, cardiopulmonary support using femoral-femoral bypass. DESIGN: Retrospective series. SETTING: A university-based, level 1 trauma center. PATIENTS: Forty-two consecutive patients treated for posttraumatic aortic pseudoaneurysm whose mean (+/- SEM) Injury Severity Score was 37 +/- 1.7. INTERVENTION: Methods of repair included clamp and sew in nine patients, left heart bypass in 24 patients, and cardiopulmonary support in nine patients. METHODS: Student's t test was used to compare interoperative blood loss, need for blood transfusion, and aortic cross-clamp time. Complications and mortality were also reviewed. RESULTS: Mean (+/- SEM) aortic cross-clamp time for clamp and sew was 28.1 +/- 3.3 minutes vs 52.5 +/- 3.7 for left heart bypass and 49.3 +/- 5.6 for cardiopulmonary support. Blood loss and the need for transfusion were comparable between groups. Complications were also comparable. CONCLUSION: Femoral-femoral cardiopulmonary support is safe to use, has a very low risk of complications, and should provide protection for the spinal cord during aortic repair. We encourage a randomized prospective trial to determine if cardiopulmonary support has a significantly lower rate of paraplegia than the clamp- and -sew technique.

Adolescent↗
PubMed1994

Improved myocardial function using cardiopulmonary support in resuscitation for hemorrhagic shock.

OBJECTIVES: To clarify the pathophysiologic characteristics of hemorrhagic shock and to assess methods of resuscitation. DESIGN: An animal experiment using sheep subjected to hemorrhagic shock and fibrillation to compare various resuscitation techniques. SETTING: An experimental laboratory setting meant to simulate hemorrhagic shock secondary to trauma. STUDY GROUPS: Group 1 animals (n = 6) were controls that were not subjected to shock and fibrillation. Group 2 animals (n = 6) were subjected to shock and fibrillation and were resuscitated with volume replacement. Group 3 animals (n = 6) were also subjected to shock and fibrillation but were resuscitated with epinephrine hydrochloride infusion. Group 4 animals (n = 6) were subjected to shock and fibrillation but were resuscitated with cardiopulmonary support. INTERVENTIONS: The shock was to a mean arterial pressure of 25 mm Hg for 1 hour followed by 5 minutes of fibrillation. Group 2 animals were resuscitated for 1 hour. Group 3 animals were supported for 6 hours on epinephrine after the shock period. Group 4 animals were supported for 1 hour on cardiopulmonary support, then were observed for another 5 hours. All animals were sedated and intubated, and a median sternotomy was performed. MAIN OUTCOMES MEASURED: Survival, hemodynamic function, lactate production, myocardial blood flow, and water content. RESULTS: Group 1 sheep showed no detrimental effects in any of the measured variables. Group 2 sheep could not be resuscitated. Group 3 sheep could be supported with epinephrine but had a 60% depression in left ventricular function and an ultimately high mortality rate (67%) when the infusion of epinephrine was discontinued. Group 4 sheep had a 100% survival rate and only a 20% deterioration in left ventricular function. CONCLUSIONS: Cardiopulmonary support improves survival and preserves left ventricular function compared with volume resuscitation with or without inotropic support in this model of hemorrhagic shock.

Animals↗
PubMed1994

Poststernotomy fractures and pain management in open cardiac surgery.

STUDY OBJECTIVES: To assess whether (1) there is an increased incidence of sternal fractures associated with internal mammary artery (IMA) revascularization in open heart surgery and (2) there is a higher incidence of pain in postoperative patients with sternal fractures. METHODS: Two hundred eighty-eight consecutive adult patients who had undergone cardiac surgery underwent median sternotomy from 1989 to 1991. IMA revascularization was used in 94 patients. The remainder underwent conventional saphenous vein graft (SVG) revascularization or other open cardiac procedure. The sternum was checked for fracture at the time of chest-wall closure. Lung volumes, arterial blood gases, respiratory rate, and oxygen requirements were measured before and after pain relief by intravenous or epidural analgesia. RESULTS: Of 288 consecutive median sternotomies, there were a total of 24 sternal fractures. IMA harvesting was associated with a significantly greater incidence of sternal fractures. In the 94 patients in whom IMA mobilization was used, there were 16 fractures; in the remaining 194 cases, there were 8 fractures (p < 0.007). Twenty-one of 24 patients were not seriously affected by their sternal fractures, whereas 3 patients suffered major respiratory compromise due to postoperative pain. Epidural analgesia was effective treatment for these three cases of severe sternal fracture pain and was not associated with any adverse consequences. All three patients had significant improvement in their respiratory condition after epidural analgesia was instituted. Respiratory rate decreased from 27 +/- 3 to 18 +/- 0.3 breaths/min (p < 0.001) and end maximum inspired volume increased from 700 +/- 1 mL to 1,525 +/- 275 mL. CONCLUSIONS: The use of sternal retraction devices for IMA harvesting in coronary bypass procedures results in an increased incidence of sternal fractures when compared with conventional SVG bypass procedures. Although most sternal fractures are well tolerated, some patients with fractures can become a significant pain management problems. Epidural analgesia is a safe and effective treatment for severe pain associated with sternal fractures and provided improved postoperative pulmonary function.

Adult↗
PubMed1994

Balloon mitral valvulotomy as a bridge to valve replacement.

Balloon mitral valvulotomy is used in treating mitral stenosis. We stabilized a near-moribund patient who had combined aortic and mitral valve stenoses with this technique on an emergency basis. Following valvulotomy, mitral valve area increased from 1.1 to 2.2 cm2, pulmonary capillary wedge pressure decreased from 31 to 21 mmHg, and cardiac index increased from 1.9 to 2.8 L/min/m2. When the patient's condition improved, we replaced the aortic and mitral valves with St. Jude Medical bileaflet prostheses. Balloon mitral valvulotomy has not been previously described as a "bridge" to operation. The patient in this report was at extremely high risk with cardiopulmonary and hepatorenal failure, and is the first where valvulotomy was used as temporary rather than definitive management. It should be considered only in cases without calcified, fibrotic valves and where the operative risk is considered prohibitive.

Adult↗
PubMed1993

Pericardial patch repair of left ventricular aneurysm.

Infectious complications associated with the use of Teflon felt buttresses in left ventricular aneurysm repair may result in serious morbidity. Use of an autologous pericardial patch is an alternative approach that should be considered. The technique, which we have used in 4 patients, is described.

Abscess↗
PubMed1993

Use of a heat exchanger to prevent hypothermia during thoracic and thoracoabdominal aneurysm repairs.

Hypothermia is a common unplanned occurrence in many patients undergoing repair of thoracic and thoracoabdominal aneurysms. Many undesirable side effects of hypothermia have been documented, including decreased cardiac output, conduction abnormalities, and blood coagulopathies. We have developed a simple system that incorporates a Sci-Med Biotherm heat exchanger into our left heart bypass circuit. This provides us with the ability to actively rewarm the patient safely and efficiently. This study looks at 16 consecutive patients undergoing repair of thoracic or thoracoabdominal aneurysms. In the 9 patients in whom the heat exchanger was used, there were no adverse effects related to the heat exchanger. All patients had significantly higher temperatures at the conclusion of the procedure than the 7 patients in whom the heat exchanger was not used.

Aortic Aneurysm↗
PubMed1989

Measurement of Ca channel activity of isolated adult rat heart cells using 54Mn.

Isolated adult rat heart cells incubated with 5 microM Mn in a medium with 1 mM Ca showed a rapid phase of Mn binding plus a slow phase of Mn uptake. The rapid phase was extracellular binding, as judged by its temperature-insensitive removal by ethylene glycol bis(beta-aminoethyl ether) N, N'-tetraacetic acid. The slow linear phase represented cellular uptake, as judged by its release with digitonin plus the ionophore A23187. Isoproterenol increased the linear rate of Mn uptake and induced spontaneous beating activity in some cells. Both effects were inhibited by nitrendipine. Electrical stimulation of the cells in suspension increased the linear rate of cellular Mn uptake. The increase was potentiated by isoproterenol, and inhibited by nitrendipine or verapamil. Stimulation-dependent Mn uptake (per milligram protein) was greater for cells from 5- to 6-week-old rats than for 8- to 9-month-old female retired breeder rats, in the presence of isoproterenol. Ryanodine increased the stimulation-dependent Mn uptake in the presence of isoproterenol, but not in its absence. We conclude: (i) that cellular uptake of 54 Mn is a good probe of Ca channel function; (ii) that isoproterenol promotes Mn influx by the channel in isolated heart cells; (iii) that cells from young rats (5-6 weeks) have a higher beta-adrenergically induced Ca channel activity than cells from mature rats (8-9 months); and (iv) that ryanodine promotes Ca channel activity (perhaps indirectly) in the presence of isoproterenol.

Age Factors↗
PubMed1989

Some determinants of quality and yield in the isolation of adult heart cells from rat.

We investigated the effect of changes in perfusate substrate and Ca content on the quality and yield of isolated adult rat heart cells. When 1 mM Ca was added to the recirculating perfusate 15 min after collagenase addition, the ATP level of cells in the heart 15 min later, and their morphology in histological section, was no different from when no Ca was added back. The cells subsequently isolated were of similar yield, but a greater percentage were rod-shaped, compared with cells isolated without Ca restoration to the perfusate. Increased yield could be obtained by including substrates in the perfusate in addition to glucose. Either fatty acids or amino acids were effective. We conclude that: (1) all cells in the heart are Ca tolerant at the end of enzyme perfusion; (2) the presence of substrates in addition to glucose can help cells survive the isolation process.

Animals↗
PubMed1989

Inhibition of Na-Ca exchange by general anesthetics.

General anesthetics, typically octanol, were found to inhibit the influx of calcium in isolated sodium-loaded adult rat heart cells, using 45Ca, quin 2, or indo 1. Inhibition by octanol, like inhibition by sodium, was competitive with calcium. Octanol and sodium together inhibited calcium influx synergistically. At physiological levels of extracellular calcium and sodium, the EC50 was 177 +/- 37 microM for octanol and 48 +/- 5 microM for decanol. These values are threefold to fourfold larger than those reported to cause 50% loss of righting reflex in tadpoles, a measure of their anesthetic effectiveness. We conclude that general anesthetics inhibit Na-Ca exchange at the sarcolemma. We suggest that octanol inhibits like sodium, and the synergism stems from the cooperativity of sodium inhibition at the binding and regulatory sites of the exchanger. Insofar as Na-Ca exchange may regulate inotropy, the inhibition of Na-Ca exchange by general anesthetics could contribute to their negative inotropic effect.

Adenosine Triphosphate↗
PubMed1989

Inhibition of ATP-sensitive potassium channels of adult rat heart cells by antiarrhythmic drugs.

We have investigated the effect of antiarrhythmic drugs on the increased potassium conductance induced in isolated adult rat heart cells by ATP depletion. The rate of 86Rb uptake in the presence of ouabain was used as a measure of potassium conductance. Treatment of cells with rotenone plus p-trifluoromethoxyphenylhydrazone (FCCP) rapidly depleted ATP levels and strongly stimulated the rate of 86Rb uptake. The stimulated uptake and the ATP depletion were inhibited by oligomycin; thus, the uptake was not induced by rotenone plus FCCP directly. The stimulated uptake, but not the ATP depletion, was inhibited potently by glyburide (IC50, 38.3 nM), quinidine (IC50, 2.7 microM), verapamil (IC50, 4.5 microM), and amiodarone (IC50, 19.1 microM). The stimulated uptake was also inhibited by tetraethylammonium ion and by 4-aminopyridine but not by tetrodotoxin or manganese. We conclude that 1) the stimulated 86Rb uptake is measuring ATP-sensitive potassium channel activity, 2) the ATP-sensitive potassium channel is strongly inhibited by quinidine, verapamil, and amiodarone, and 3) this inhibition may contribute to the antiarrhythmic action of these drugs.

Adenosine Triphosphate↗
PubMed1988

Comparison of survival in cardiac surgery at a Veterans Administration hospital and its affiliated university hospital.

Survival data were reviewed for 3330 open cardiac procedures from 1975 through 1984 at the William S. Middleton Memorial Veterans Hospital, Madison, Wis, and the University of Wisconsin Hospitals and Clinics, Madison. Respective operative survivals were 98.6% and 98.7% for myocardial revascularizations with vein graft or internal mammary artery (CABG), 96.2% and 96.8% for CABG reoperation, 97.8% and 95.9% for aortic valve replacement, 96.3% and 90.3% for aortic valve replacement plus CABG, 100.0% and 94.9% for mitral valve replacement, and 100.0% and 82.9% for mitral valve replacement plus CABG. There were no significant differences in six-year survival curves between hospitals despite threefold differences in average annual caseload (88 vs 294). This suggest that residency-directed cardiac surgery programs can function equally as well at a Veterans Administration hospital as at an affiliated university hospital.

Cardiac Surgical Procedures↗
PubMed1988

Synchronous depletion of ATP in isolated adult rat heart cells.

We tested the hypothesis that isolated adult rat heart cells could be depleted of most of their ATP without undergoing contracture. Two strategies for ATP depletions were employed. First, cells were exposed to a high level of rotenone plus FCCP. The cells lost 90% of their ATP within 3 min without change in sarcomere length before undergoing contracture. Even though ATP levels were so low, glycolysis from glycogen was maximally activated at this time. Second, cells exposed to repeated cycles of acidic anoxia were depleted of 77% of their ATP without change in sarcomere length and remained rod-shaped when restored to normoxia and neutral pH. The hypothesis was thus confirmed. The results support the previously developed concept that ATP decline in cells can be synchronous, with a similar decline in all cells, or asynchronous, with a sudden decline in different cells at different times. Whether the decline is synchronous or asynchronous depends on the conditions of metabolic impairment. This concept can explain the pattern of ATP decline observed in whole hearts during ischemia, and also the mechanism by which glycolytic ATP appears to protect against contracture.

Adenosine Triphosphate↗
PubMed1988

Noninvasive testing of cerebral perfusion reserve prior to coronary artery bypass graft surgery.

Cerebral perfusion reserve testing using fluorine-18-fluoromethane and positron emission tomographic brain scanning to define cerebral blood flow abnormalities was performed in 5 patients being considered for combined coronary and carotid reconstructive surgery. Blood flow testing during normocapnia and following hypercapnia was utilized in these patients to determine the hemodynamic significance of known extracranial carotid artery occlusive lesions. Reserve diminution in 2 of these patients prompted combined surgery, whereas normal reserve values in the other 3 prompted coronary surgery alone. Results obtained in this preliminary series show how preoperative noninvasive testing of cerebral perfusion reserve adds to the diagnostic evaluation of patients with widespread vascular disease.

Brain↗
PubMed1988

The fate of aortic valve homografts 12 to 17 years after implantation.

Results of long-term follow-up of an early cohort of patients receiving aortic valve homografts for aortic stenosis and aortic insufficiency are presented. All patients were operated upon by a single surgeon from 1966 to 1971. Eighty-three patients underwent insertion of 85 homograft aortic valves. Homografts were sterilized with either betapropiolactone (39 valves) or gamma irradiation (41 valves) and were inserted following storage in nutrient medium (16 valves) or after cryopreservation (51 valves). All homograft valves were sutured in the subcoronary position using a freehand technique. There was a 55 percent 15-year actuarial patient survival and a 16 percent 15-year actuarial homograft survival in this cohort. Homograft valve failure occurred gradually allowing the patients to be observed until they developed hemodynamic compromise at which time elective valve replacement was performed.

Actuarial Analysis↗