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Biomedical subjects

J Hultman

Publications and source records attributed to J Hultman.

At least 19 recordsLinked to original sources

[Policy document. Catheter-based diagnosis and treatment of coronary diseases].

Diagnostic coronary angiography and percutaneous coronary interventions (PCI) are rapidly developing fields. In-house thoracic surgery backup is no longer a prerequisite for PCI. The demand for physicians trained in interventional cardiology has created a need to formalise such education. The Swedish societies of cardiology and thoracic radiology have agreed on a policy document establishing the details of this education. It is the responsibility of the tutor to decide when the pupil has achieved adequate skills.

Angioplasty, Balloon, Coronary↗

Perioperative transoesophageal echocardiography with low-dose dobutamine stress for evaluation of myocardial viability: a feasible approach?

BACKGROUND: The feasibility of low-dose dobutamine stress combined with transoesophageal echocardiography (TEE) to detect viable left ventricular myocardium was evaluated in 22 anaesthetised patients prior to sternotomy for elective coronary artery bypass grafting (CABG). METHODS: After baseline measurements, a dobutamine infusion beginning with 5 micrograms.kg-1.min-1 was started and eventually increased to 10 micrograms.kg-1.min-1. Viability was assessed as visual improvement of left ventricular wall motion (LVWM). The criteria for discontinuation of the infusion were: 1. any changes in LVWM, 2. an increase in preanaesthetic blood pressure exceeding 40 mmHg, and/or a > 20% increase in preanaesthetic heart rate compared to preanaesthetic levels. An off-line evaluation of LVWM was based upon visualisation of the left ventricle in a transgastric short-axis mid-papillary (mid-P) view, and the left ventricle was divided into anterior, septal, inferior, and lateral segments. Moreover, an off-line semiautomatic analysing system was used for assessing regional and global LVWM. With this analysis the effects on LVWM from changes in preload and afterload could be addressed. RESULTS: 19 patients showed a decreased LVWM in one or several segments at baseline. A total of 36 segments exhibited decreased LVWM (an average of 1.9 segments/patient). Of these, 22 segments (61%) improved with dobutamine, while 12 segments (33%) did not, and 2 (6%) became more dysfunctional. Another 6 segments with normal motion at baseline became dysfunctional with dobutamine. According to the off-line semiautomatic analysing system for LVWM, there were no statistically significant changes with dobutamine stimulation. Only one patient showed an increased postoperative aspartateaminotransferase (ASAT) value (3.0 mmol.l-1) but no ECG changes. CONCLUSION: Since we regard the visual assessment of LVWM as being more applicable for this protocol than the semiautomatic analysis, we conclude that low-dose dobutamine stress echocardiography seems to be a feasible method for detecting viable myocardium in the anaesthetised patient scheduled for elective CABG surgery. However, the semiautomatic analysis complemented our findings, since the variations in pre- and afterload did not significantly change the size of the left ventricle, which hereby would imply LVWM changes.

Aged↗

Differences in costs of treatment for foot problems between podiatrists and orthopedic surgeons.

We examined charge data for health insurance claims paid in 1992 for persons under age 65 covered by a large California managed care plan. Charge and utilization comparisons between podiatrists and orthopedic surgeons were made for all foot care and for two specific foot problems, acquired toe deformities and bunions. Podiatrists provided over 59% of foot care services for this commercial population of 576,000 people. Podiatrists charged 12% less per individual service than orthopedists. However, podiatrists performed substantially more procedures per episode of care and treated patients for longer time periods, resulting in 43% higher total charges per episode. Hospitalization was infrequent for all providers, although podiatrists had the lowest rates. In a managed care setting in which all providers must adhere to a preestablished fee schedule, regardless of specialty, the higher utilization by podiatrists should lead to higher overall costs. In some cases, strong utilization controls could offset this effect. We do not know if the utilization difference is due to actual treatment or billing differences. Further, we were unable to determine from the claims data if one specialty had better outcomes than the other.

Blue Cross Blue Shield Insurance Plans↗

Haemostasis at low heparin dosage during cardiopulmonary bypass with heparin-coated circuits in pigs.

Cardiopulmonary bypass (CPB) causes activation of cascade systems. Although heparin coating of CPB circuits improves biocompatibility, the effects on coagulation remain controversial. Theoretically, heparin coating should permit the reduction of systemic anticoagulation during CPB. We investigated influences on haemostatic variables in animal CPB, comparing heparin-coated circuits and reduced systemic heparinization (group HC) with uncoated circuits and full heparinization (group C). Twenty pigs underwent 2-h CPB. Seven (HC, n = 4; C, n = 3) were weaned from CPB and studied for up to 4 h. Total administered heparin was 470 +/- 6 IU/kg (mean +/- SEM) in group C and 100 +/- 0 IU/kg in group HC. Protamine dosage was significantly reduced in group HC. In group C, levels of prothrombin complex, factor VIII and adhesive platelets were reduced significantly during CPB, and postoperatively there were significantly lower values of prothrombin complex, fibrinogen, antithrombin III, factor VIII and adhesive platelets but a significantly increased concentration of von Willebrand factor and cumulative bleeding after 4 h. In conclusion, heparin-coated CPB circuits combined with lowered heparin dosage reduced coagulation factor consumption and preserved platelet function, possibly contributing to improved postoperative haemostasis.

Animals↗

Haemostasis at low heparin dosage during cardiopulmonary bypass with heparin-coated circuits in pigs.

Cardiopulmonary bypass (CPB) causes activation of cascade systems. Although heparin coating of CPB circuits improves biocompatibility, the effects on coagulation remain controversial. Theoretically, heparin coating should permit the reduction of systemic anticoagulation during CPB. We investigated influences on haemostatic variables in animal CPB, comparing heparin-coated circuits and reduced systemic heparinization (group HC) with uncoated circuits and full heparinization (group C). Twenty pigs underwent 2-h CPB. Seven (HC, n = 4; C, n = 3) were weaned from CPB and studied for up to 4 h. Total administered heparin was 470 +/- 6 IU/kg (mean +/- SEM) in group C and 100 +/- 0 IU/kg in group HC. Protamine dosage was significantly reduced in group HC. In group C, levels of prothrombin complex, factor VIII and adhesive platelets were reduced significantly during CPB, and postoperatively there were significantly lower values of prothrombin complex, fibrinogen antithrombin III, factor VIII and adhesive platelets but a significantly increased concentration of von Willebrand factor and cumulative bleeding after 4 h. In conclusion, heparin-coated CPB circuits combined with lowered heparin dosage reduced coagulation factor consumption and preserved platelet function, possibly contributing to improved postoperative haemostasis.

Animals↗

Transoesophageal echocardiography and acoustic quantification in assessing regional left ventricular wall motion.

Acoustic Quantification (AQ) is a technique based on analysis of ultrasonic integrated backscatter. It enables a real time detection of blood-tissue borders and numbers the end-diastolic and end-systolic areas throughout the cardiac cycle. AQ added to the 2D image therefore offers an on-line estimate of global ventricular function in the operating room. Since AQ is dependent on a good 2D image as well as adjustment of both transmit- and time gain control the question arises whether this leads to a different assessment, compared to the 2D image only, of off-line assessment of regional left ventricular wall motion (LVWM). Twenty-three consenting patients scheduled for elective coronary bypass grafting were studied. A total of 31 observations were performed and divided into 21 short axis and 10 three chamber long axis views. Regional LVWM score was assessed off-line (video recordings postoperatively) by two independent readers on two occasions. There was no intra-reader difference in assessment of regional LVWM in the short axis view when AQ was added to the 2D image. On the other hand, the interreader difference was highly significant both without and with AQ (P = 0.0001) in this view. In the long axis view the intra-reader difference was significant (P = 0.0008 and P = 0.004 respectively), while the inter-reader difference was non-significant. However, the overall intra-reader and inter-reader agreement was 78% or higher except for the intra-reader difference in the long axis view.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustics↗

Parasympathetic muscarinic stimulation limits noradrenaline induced myocardial creatine kinase release: a study in the isolated perfused working rat heart.

It has long been known that high concentrations of catecholamines may induce myocardial damage, and aggravate ischaemic injury. It has also been shown that beta-blockade may protect the myocardium from ischaemic damage. Stimulation of muscarinic receptors modulates beta-adrenergic receptor affinity for isoproterenol and attenuates isoproterenol induced adenylyl cyclase activation. Effects of muscarinic receptor stimulation were therefore investigated in isolated anterogradely perfused rat hearts under different experimental conditions. One group of hearts was perfused with noradrenaline, 10(-6) mol l-1 for 45 min, and another group was perfused with different carbachol concentrations (3 x 10(-7)-10(-5) mol l-1) with or without noradrenaline 10(-6) mol l-1, for 45 min. Release of creatine kinase to the perfusion buffer was taken as a sign of cell damage. Heart rate, left ventricular maxdP/dt and left ventricular pressure were measured throughout the perfusion time by insertion of a 20 gauge cannula through the left ventricular wall near the base. Carbachol (3 x 10(-7) mol l-1) alone induced a decrease of heart rate by 25% and maxdP/dt by 13%. Noradrenaline produced a 20% increase in heart rate, whereas the combination of noradrenaline plus carbachol induced a minor decrease in heart rate. Muscarinic receptor stimulation alone decreased myocardial contractility. However, when combined with noradrenaline no decrease in contractility was seen. Also, the release of creatine kinase to the perfusion buffer containing the combination of carbachol plus noradrenaline was reduced. Thus, muscarinic receptor stimulation protected the myocardium from catecholamine induced damage at concentrations where no change in contractility was seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Decreased blood loss after cardiopulmonary bypass using heparin-coated circuit and 50% reduction of heparin dose.

In a randomized, double-blind study of patients undergoing elective coronary artery grafting, the effect of heparin-coated circuit combined with 50% reduction of systemic heparin bolus was investigated. Ten patients comprised group HC (heparin-coated) and ten group C (controls). The mean total doses of heparin were 172 IU/kg in group HC and 416 IU/kg in group C and the respective protamine doses were 0.96 and 3.96 mg/kg (both p < 0.001). Activated clotting times during cardiopulmonary bypass were significantly shorter in group HC, and both intra- and postoperative bleeding was significantly less than in group C (7.7 vs. 11.7 ml/kg, p = 0.036, and 6.9 vs. 9.7 ml/kg, p = 0.004). Hemoglobin loss via the drains was 22.5 g in group HC and 43.7 g in group C (p < 0.005). Hemolysis at the end of bypass was significantly greater in group C. Apart from one perioperative myocardial infarction in group HC the postoperative course was uneventful. Use of a heparin-coated circuit is concluded to permit complication-free reduction of heparin and protamine doses and to decrease both intra- and postoperative bleeding, which may favorably influence the outcome of coronary artery grafting.

Blood Coagulation↗

Heparin-coated cardiopulmonary bypass circuits reduce blood cell trauma. Experiments in the pig.

Blood cell trauma and postoperative bleeding remain important problems in cardiopulmonary bypass (CPB). We compared heparin-coated with non-coated circuits in the pig. Twenty animals were perfused for 2 h at normothermia using membrane oxygenators (Bentley Bos 50). Two groups were studied. In the non-coated group (NC, n = 11) the CPB circuits used were without a heparin coating. This group had systemic heparinization of 400 IU/kg to maintain an ACT (activated clotting time) of over 400 s during CPB. In the coated group (C, n = 9), all surfaces exposed to blood in the CPB circuits were heparin-coated. This group had the heparin dose reduced to 25% (100 IU/kg) without further administration regardless of ACT. During CPB, group C displayed shorter ACT (per definition), higher platelet count, platelet adhesion and lower fibrinolysis and haemolysis (P less than 0.05) as compared to group NC. No thromboembolic events were detected during CPB. Three animals in group NC and 4 animals in group C were weaned from CPB and protaminized. Four hours postoperatively, the leucocyte consumption was two-fold greater and blood loss about four-fold greater in group NC as compared with group C (P less than 0.05). Perfusion with heparin-coated surfaces reduces blood cell trauma. The decreased postoperative blood loss observed in group C is probably explained by the reduced dosages of heparin and protamine.

Animals↗

Effects of adenosine infusion on the pig heart during normothermic ischemia and reperfusion.

Possible enhancement of myocardial protection during ischemia and reperfusion by administration of adenosine was evaluated in a pig heart model. Adenosine (100 micrograms/kg/min) was infused into the aortic root during ischemia in group AI (n = 5) and into the right atrium during reperfusion in group AR (n = 6). Group C (n = 6) served as controls. During cardiopulmonary bypass the hearts were subjected to 30 min of normothermic ischemia and 15 min of reperfusion before weaning. In group AI the stroke work index 30 and 90 min after ischemia and the mean arterial pressure 30 min after ischemia were significantly higher than in group C. These parameters did not differ significantly between groups AR and C. All groups showed decrease in myocardial adenosine triphosphate (ATP) and adenylate charge potential (ACP) during ischemia and partial (ATP) or complete (ACP) restoration after ischemia. Adenosine infusion into the aortic root during ischemia (adenosine cardioplegia) thus resulted in improved postischemic heart function, although biochemical correlates in ATP and ACP were not apparent.

Adenosine↗

Heparin-coated equipment reduces complement activation during cardiopulmonary bypass in the pig.

Complement activation was studied during cardiopulmonary bypass (CPB) in the pig. One group of animals was perfused for 2 h using a standard extracorporeal circuit including a hollow fiber membrane oxygenator with full systemic heparinization. Another group was treated in the same way, except that bypass was performed through a heparin-coated CPB circuit (Carmeda Bio-Active Surface, CBAS) and systemic heparinization was reduced by 75%. It was found that complement activation during CPB, measured as changes in the ratio C3d/C3, was significantly less in the CBAS group, most probably reflecting a better biocompatibility.

Animals↗

Influence of adenosine on left ventricular performance in conscious dogs.

Adenosine, a potent vasodilator of both the peripheral and coronary vasculature, is increasingly used to produce controlled hypotension in the clinical and experimental setting. To define the influence of adenosine on left ventricular (LV) performance in conscious closed-chest dogs were studied six chronically instrumented autonomically blocked animals before and after the administration of 0.3, 0.6, and 1.2 microM.kg-1.min-1 infusions of adenosine. Systolic performance was quantified by the end-systolic pressure-volume (Pes-Ves) and stroke work end-diastolic volume (SW-EDV) relations. Active diastolic performance was quantified by the time constant of LV relaxation (T), whereas passive diastolic properties were assessed by comparing LV pressures at a common LV volume. Despite a decrease of mean arterial pressure of 51 mmHg, adenosine did not change the slope of the Pes-Ves relation or the end-systolic volume at a pressure of 100 mmHg. The slope of the SW-EDV relation was also unchanged, and its volume axis intercept was slightly reduced. There were no differences in T or in the diastolic pressure at a common LV volume. Thus adenosine appears to have little influence on systolic or diastolic LV performance aside from its marked affect on afterload, indicating it is a useful agent for producing controlled hypotension.

Adenosine↗