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S E Fremes

Publications and source records attributed to S E Fremes.

At least 55 records · Page 3Linked to original sources
PubMed1994

Metaanalysis of prophylactic drug treatment in the prevention of postoperative bleeding.

Prophylactic drug treatment is one of several strategies to reduce postoperative blood loss and potentially limit homologous blood use in open heart surgery. A computerized MEDLINE search supplemented with manual bibliography reviews was performed for randomized clinical trials published in peer-reviewed English-language journals from January 1980 to June 1993. A metaanalysis was conducted of trials evaluating desmopressin (group DD, n = 13), epsilon-aminocaproic acid or tranexamic acid (group EA, n = 4), and aprotinin (group AP, n = 16). Eligible studies used placebo controls and administered the drug in a prophylactic manner. The primary study end point was postoperative chest tube loss (mL, mean +/- standard deviation). There was a significant reduction in postoperative chest tube loss detected for each of the active treatments versus the placebo (DD versus controls: percent reduction 0.11, p = 0.0021; EA versus controls: percent reduction 0.30, p < 0.0001; and AP versus controls: percent reduction 0.36, p < 0.0001). Therapy with EA or AP was associated with a greater reduction in chest tube loss than DD (EA versus DD, p = 0.0033, and AP versus DD, p < 0.0001). Secondary study end points were transfusion requirements, chest reexploration, and perioperative mortality. The volume of postoperative red cell transfusion (mean +/- standard deviation) was reduced with EA (p < 0.0001) or AP treatment (p < 0.0001) compared with a placebo or DD, whereas the proportion of patients given transfusions was limited only in the AP-treated patients (odds ratio 0.23; 95% confidence interval, 0.16 to 0.33; p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aminocaproic Acid↗
PubMed1994

Cardiac storage with UW solution and glucose.

Previous investigations from our institution using an isolated human cardiomyocyte model concluded that glucose supplementation of University of Wisconsin solution (UWS) was beneficial with respect to adenine nucleotide and protein recovery. We wished to confirm these results using an isolated heart model. Rodent hearts were frozen in liquid nitrogen (control) or flushed and stored in UWS for 8 hours at 0 degrees C or UWS supplemented with 10, 20, or 30 mmol/L glucose. Experimental hearts were assessed at end-storage or after 45 minutes of reperfusion on a Langendorff apparatus. Adenine nucleotides were assessed by high performance liquid chromatography. In parallel experiments, ventricular function was assessed before and after storage in Langendorff-perfused hearts instrumented with a left ventricular balloon. Glucose supplementation was associated with greater poststorage (20 and 30 mmol/L glucose) and postreperfusion (10, 20, and 30 mmol/L glucose) adenosine triphosphate levels than unmodified UWS. Developed pressure (expressed as a percentage of control values) was increased with 10 mmol/L glucose (75.2% +/- 7.9%, mean +/- standard deviation) compared with unmodified UWS (64.6% +/- 6.6%; p < 0.05). Coronary flow was greater with 10 (72.6% +/- 10.7%) or 20 mmol/L (71.2% +/- 12.5%) versus 0 mmol/L glucose (58.6% +/- 12.1%, p < 0.05). The data support previous in vitro findings and suggest that the addition of 10 mmol/L glucose to UWS is associated with enhanced recovery after prolonged hypothermic storage.

Adenine Nucleotides↗
PubMed1994

Initial clinical experience with the Toronto Stentless Porcine Valve.

We report our initial experience from April 1992 to November 1993 with a stentless porcine valve (Toronto SPV Valve, St. Jude Medical) for aortic valve replacement (AVR) in 21 consecutive patients and compare this group to a matched cohort that underwent AVR with a Hancock II (Medtronic) bioprosthesis. There were no hospital deaths in either group. Postoperative hospitalization was 5.5 +/- 0.8 versus 7.0 +/- 2.3 days (p = 0.004). Aortic cross-clamp time was 114.5 +/- 15.7 min in the SPV group and 96.0 +/- 25.0 min in the Hancock II group (p = 0.003). Complications in the SPV group were: one patient suffered perioperative infarction, one patient required late reoperation for left main stenosis, and one patient died suddenly following femoral thrombectomy at another center. Complications in the Hancock II group included: one patient with postoperative low output syndrome, and two late deaths (one from an aortic dissection and the other from chronic liver disease secondary to alcohol abuse). Comparison data indicate that the average size valve implanted in the SPV group was higher than in the Hancock II group (26.3 +/- 1.9 vs 24.0 +/- 1.9, p = 0.001). In the SPV group, 16 patients had 0 or trivial regurgitation and 1+ regurgitation was seen in 5 patients; regurgitation did not change over a 12-month follow-up. We observed a decrease in gradients over time (p < 0.01). Our results are compatible with a hypothesis that the ventricle undergoes remodeling over time, once the obstruction is relieved. We think the stentless design is an important feature that allows this to occur.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Cardiopulmonary bypass, temperature, and central nervous system dysfunction.

BACKGROUND: Neurological injury is an important cause of morbidity and mortality after cardiac surgery. With the advent of warm heart surgery, the neuroprotective role of hypothermic cardiopulmonary bypass (CPB) has come under increasing scrutiny. Preliminary work by us in the area found no increased risk of neurological morbidity with normothermic CPB in a small group of patients and suggested a possible benefit. The purpose of the present study is to compare the incidence of neurological and neuropsychological dysfunction in a larger number of patients randomized to warm or cold aortocoronary bypass surgery. METHODS AND RESULTS: With the approval of the institutional research ethics committee, 201 aortocoronary bypass patients were randomized to normothermic or moderate hypothermic CPB and subjected to neurological and neuropsychological evaluation. These subjects were a subset of patients enrolled in a large multicenter trial comparing warm versus cold heart surgery. The examinations took place preoperatively, 5 days after operation, and a 3-month follow-up. The examination consisted of a clinical neurological examination and a brief neuropsychological test battery. The neuropsychological tests included the Buschke selective reminding procedure, the Wechsler memory scale-revised visual reproduction subtest, the trial making test (parts A and B), the Wechsler adult intelligence scale-revised digit symbol subtest, and the grooved pegboard test. The examiner and subjects were unaware of the CPB temperature allocation (warm, > 34 degrees C; cold, < or = 28 degrees C). Statistical analysis was performed using the SAS statistical software package. Two hundred one patients were enrolled in the study. Of these, 155 patients completed the entire protocol and were included in the final analysis (warm group, n = 78; cold group, n = 77). One patient in the warm group died perioperatively from a massive hemispheric stroke. Another warm group patient was unable to complete neuropsychological evaluation because of a perioperative stroke. Thus, 153 patients completed the entire series of neuropsychological tests. A total of 6 patients (warm group, n = 2; cold group, n = 4; P = NS) suffered from perioperative focal neurological deficits. There was a consistent deterioration in scores from tests of psychomotor speed/coordination (trial making, digit symbol, pegboard) in the early postoperative period, which resolved by the 3-month follow-up. Tests of memory (Buschke, Wechsler memory scale) showed no evidence of patient deterioration in the postoperative period. No difference was seen between the warm and cold groups. CONCLUSIONS: In this randomized trial of normothermic versus hypothermic CPB, we found deterioration in scores of tests of psychomotor speed but not of memory in the early postoperative period. We were unable to demonstrate any neuroprotective effect from moderate hypothermia in this patient population.

Blood↗
PubMed1993

Comparison of two experimental models for assessment of cardiac preservation.

Previous studies from this institution using human cell cultures have suggested that University of Wisconsin solution is preferred for prolonged hypothermic storage for cardiac transplantation. The primary objective of this study was to evaluate the effectiveness of extended cardiac preservation with University of Wisconsin solution by assessing the time-related changes of purine metabolites using two different models of cold storage. Isolated rat hearts (n = 6/group) or human ventricular myocyte cultures (n = 7 dishes/group) were assessed after 0, 6, 12, and 24 hours in University of Wisconsin solution at 0 degrees C using high-performance liquid chromatography. Adenosine triphosphate content decreased from 18.1 +/- 5.4 to 9.6 +/- 2.7 mumol/g dried weight by 12 hours and to 1.0 +/- 0.6 mumol/g by 24 hours (p < 0.0001 by analysis of variance) in the rat model. Adenosine triphosphate content decreased from 0.64 +/- 0.42 to 0.14 +/- 0.11 nmol/micrograms DNA at 6 hours and to 0.04 +/- 0.03 nmol/micrograms DNA by 24 hours (p < 0.00001) in the cardiomyocytes. Inosine monophosphate content increased from 0.1 +/- 0.2 to 10.8 +/- 1.0 by 24 hours (p < 0.0001) in the rat studies. Inosine monophosphate values tended to increase up to 12 hours (p = 0.06) in the cell cultures and then declined. Adenosine concentration increased from 0.3 +/- 0.3 to 2.3 +/- 0.9 mumol/g at 6 hours and declined thereafter (p < 0.0005) in the rodent hearts. Adenosine concentration increased from 0.03 +/- 0.02 to 1.53 +/- 0.72 nmol/micrograms DNA at 6 hours (p < 0.0001) in the cardiomyocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1993

Optimal antithrombotic therapy following aortocoronary bypass: a meta-analysis.

To evaluate the role of antithrombotic therapy, on preserving graft patency, we performed a meta-analysis of randomized clinical trials involving aspirin (ASA), dipyridamole (D), anticoagulants (AC) and placebo or nontreatment controls (P). Manual literature searches were performed supplemented by computerized MEDLINE listings complete to July 1991. Saphenous vein graft occlusion was determined by angiography (patients with > or = 1 distal anastomotic occlusion). The trial data were aggregated with the methods of Mantel and Haenszel. The results are reported as odds ratios (OR) +/- 95% confidence intervals (CI). Seventeen trials were evaluated. Aspirin strongly influenced graft occlusion [ASA +/- D vs P: OR 0.60, 95% CI 0.51, 0.71, P < 0.0001], but dipyridamole provided no additional benefit [ASA+D vs ASA: OR 0.94, 95% CI 0.72, 1.24, P = 0.71]. Anticoagulants reduced graft occlusion [AC vs P: OR 0.56, 95% CI 0.33, 0.93, P = 0.025] and the results were similar to that achieved with aspirin [ASA vs AC: OR 0.95, 95% CI 0.62, 1.44, P = 0.87]. The combination of aspirin and anticoagulants was superior to anticoagulants alone in two limited trials [ASA+AC vs AC: OR 0.55, 95% CI 0.33, 0.88, P = 0.01]. A low (100 mg) to medium (325 mg) daily aspirin dosage was more effective than a high dose (975 mg). Early postoperative treatment (< or = 6 h) strongly influenced graft occlusion while preoperative administration provided no additional benefit. No mortality advantage was identified for any antithrombotic therapy. Aspirin or anticoagulants enhance saphenous vein graft patency following aortocoronary bypass surgery, and a combination thereof deserves further investigation in a trial large enough to detect the effects of these treatments with respect to clinical events.

Anticoagulants↗
PubMed1993

Does coronary endarterectomy adversely affect the results of bypass surgery?

Coronary endarterectomy (TEA) is performed infrequently during coronary artery bypass graft (CABG) surgery due to the impression that it results in higher rates of myocardial infarction (MI), operative mortality (OM), and poor long-term outcome. To assess the effectiveness of TEA, 1,228 patients undergoing isolated CABG between 1982 and 1989 were evaluated. The incidence of OM (3.2%) and MI (6.0%) following TEA was similar to conventional CABG (OM = 3.8%, MI = 5.5%, p = NS). The incidence of low output syndrome (LOS, 15.1%) and intraaortic balloon pump insertion (IABP, 4.5%) following TEA was similar to conventional CABG (LOS = 12.6%, IABP = 6.0%, p = NS). The highest level of the cardiac specific isoenzyme (CK-MB) released following surgery was similar for the TEA group (46 +/- 49) and conventional CABG group (42 +/- 44, p = NS). Ventricular dysfunction, urgent surgery, left main stenosis, advanced age, and reoperative surgery were similar in the TEA and conventional CABG groups. At a mean follow-up of 4.2 years, 65.6% of all TEA patients were free of angina, 44.4% were gainfully employed, and 62% were in New York Heart Association Class I. The incidence of late myocardial infarction was 5.4%. The 5-year actuarial survival was 90%. Patients with double TEA and limited TEA ( < or = 3 cm TEA specimens) tended to have a lower 5-year survival. With strict criteria for selection of TEA patients and with significant technical experience, the short- and long-term results of TEA are comparable to conventional CABG.

Adult↗
PubMed1992

Central-nervous-system dysfunction after warm or hypothermic cardiopulmonary bypass.

The increasing popularity of warm heart surgery led us to assess the effect of temperature during cardiopulmonary bypass (CPB) on neuropsychological function after coronary surgery. 34 patients enrolled in a randomised trial of normothermic versus hypothermic CPB were subjected to a battery of psychomotor and memory tests before and after their operations. The mean nasopharyngeal temperature for warm CPB was 34.7 (SD 0.5) degrees C and that for hypothermic CPB was 27.8 (2.0) degrees C. In all seven neuropsychological tests the postoperative scores were better in the warm CPB than in the hypothermic group, although only one difference achieved significance (trial-making test A; p less than 0.023). Thus, neurological function after normothermic CPB seems to be no worse than that after hypothermic procedures.

Body Temperature↗
PubMed1992

A randomized study of the systemic effects of warm heart surgery.

The technique of warm heart surgery is defined as continuous warm blood cardioplegia and normothermic cardiopulmonary bypass. Although the systemic effects of traditional myocardial protection are well known, the effects of warm heart surgery are not. In a prospective trial, 204 patients undergoing coronary artery bypass grafting were randomized to the warm heart surgery technique (normothermic group) or traditional intermittent cold blood cardioplegia and cardiopulmonary bypass (hypothermic group). The groups had similar heparin sodium requirement, activated clotting times, urine output, hematocrit, and blood product utilization. There were no differences in hemodynamics immediately after cardiopulmonary bypass. The normothermic patients had a higher incidence of spontaneous defibrillation at cross-clamp removal (84%) than the hypothermic patients (33%) (p less than 0.01). An increase in the flow rate of low K+ cardioplegia was necessary to eradicate electrical activity during aortic occlusion more often in the normothermic patients (20%) than in the hypothermic patients (3%) (p less than 0.01). When low K+ cardioplegia was ineffective, high K+ cardioplegia was necessary to eradicate electrical activity in 31% of the normothermic patients compared with 10% of the hypothermic patients (p less than 0.05). The total cardioplegia volume delivered to the normothermic group (4.7 +/- 1.9 L) was higher than that delivered to the hypothermic group (2.6 +/- 0.8 L) (p less than 0.01). Although urine output was similar in both groups, the serum K+ levels were higher in the normothermic group (5.7 +/- 0.8 mmol/L) than in the hypothermic group (5.3 +/- 0.8 mmol/L) (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1992

In vitro assessment of the effects of glucose added to the University of Wisconsin solution on myocyte preservation.

BACKGROUND: University of Wisconsin solution (UWS) has been successfully used for liver transplantation and may be beneficial for hypothermic cardiac storage. The addition of glucose may enhance myocardial preservation. METHODS AND RESULTS: Cultured human ventricular myocytes (eight dishes per group) were stored at 0 degree C for 12 hours in either unmodified UWS or UWS with glucose (1, 3, 10, 30, or 100 mmol/l). Cells were assayed for protein by spectrofluorometry and adenine nucleotides by high performance liquid chromatography after storage. Protein recovery, adenosine triphosphate (ATP), adenosine diphosphate (ADP), and total adenine nucleotides (ATP+ADP+AMP) were all depleted after storage (p < 0.0001 by ANOVA). Protein recovery (p < 0.005), ATP (p < 0.05), and ADP (p < 0.05) were increased with glucose administration compared with unmodified UWS. Improvement was maximal using 30 mmol/l (protein, 0 mmol/l = 0.48 +/- 0.14 and 30 mmol/l = 0.65 +/- 0.11 mg per dish; ATP, 0 mmol/l = 3.08 +/- 0.63 and 30 mmol/l = 4.32 +/- 0.90 nmol/mg protein; ADP, 0 mmol/l = 3.76 +/- 0.80 and 30 mmol/l = 4.63 +/- 0.38 nmol/mg protein, mean +/- SD). Total adenine nucleotides tended to increase at any glucose concentration (p = 0.07 by ANOVA) and were significantly better with 30 mmol/l glucose (0 mmol/l = 7.61 +/- 1.58 and 30 mmol/l = 9.62 +/- 1.08 nmol/mg protein). CONCLUSIONS: Increasing the glucose concentration from 0 to 30 mmol/l improved adenine nucleotide and cellular protein preservation in this in vitro assessment.

Adenine Nucleotides↗
PubMed1992

Coronary artery bypass grafting in patients with poor ventricular function. Cardiovascular Surgeons of the University of Toronto.

Although patients with severe ventricular dysfunction have improved long-term survival times after coronary bypass procedures, operative morbidity and mortality rates remain high. This study was designed to identify the contemporary risk factors for isolated coronary artery bypass grafting in this high-risk subgroup. Between January 1982 and December 1990, a total of 12,471 patients underwent isolated coronary artery bypass grafting. The 9445 patients with preoperative ejection fractions greater than 40% had a lower operative mortality rate (2.3%) than that of the 2539 patients with ejection fractions between 20% and 40% (4.8%) and that of the 487 patients with ejection fractions less than 20% (9.8%; p less than 0.001). However, patients with ejection fractions of less than 20% were demographically distinct from those with higher ejection fractions. This group was older, with fewer women, a higher frequency of left main stenosis, and more frequent requirement of urgent operation for unstable angina. The risk factors for operative death also varied with preoperative ejection fraction. The traditionally accepted risk factors--urgency of operation, left main coronary artery stenosis, reoperation, sex, and age--were predictive of risk of operative death for patients with ejection fractions greater than 40%. The risk of operative death for patients with ejection fractions between 20% and 40% was predicted by urgency of operation, reoperation, sex, myocardial protection, and age. The only predictor of risk of operative death for patients with ejection fractions less than 20% was urgency of operation. Patients undergoing isolated coronary artery bypass grafting who have severe ventricular dysfunction are therefore a highly selected, high-risk subgroup of patients who risk depends on the urgency of operation. Strategies to improve the results in these patients should be focused on patient selection, improvement of myocardial protection, and more aggressive preoperative treatment of myocardial ischemia.

Age Factors↗
PubMed1991

Technique and pitfalls of retrograde continuous warm blood cardioplegia.

The recent development of normothermic myocardial preservation and systemic perfusion during bypass has questioned the fundamental need for hypothermia during cardiac operations. The antegrade technique of almost continuous perfusion by the aortic root and vein grafts has been supplemented by continuous normothermic blood cardioplegia through the coronary sinus. Recently, great interest has been shown in this technique. It is important to describe the method in detail along with its potential shortcomings and dangers. This communication describes the technical details, pitfalls, and shortcomings of retrograde continuous warm blood cardioplegia.

Blood↗
PubMed1991

The limits of cardiac preservation with University of Wisconsin solution.

Previous studies from this institution have suggested that University of Wisconsin solution is preferred for prolonged cardiac storage and preserves high-energy phosphates better than other storage fluids. University of Wisconsin solution contains adenosine (5 mmol/L), which may maintain the concentration of myocardial adenine nucleotides. Cultures of human adult myocytes were grown from left ventricular biopsy specimens obtained from patients undergoing coronary bypass procedures. Cells (seven to nine dishes per group) were rinsed of culture medium and stored at 0 degrees C in University of Wisconsin solution. Cells were analyzed for adenine nucleotide content after 1, 6, 12, and 24 hours of storage by high-performance liquid chromatography (units = nmol/microgram DNA) and compared with control samples (0 hour). Adenosine concentration increased from 0.03 +/- 0.02 (mean +/- standard deviation) to 1.77 +/- 1.03 by 1 hour (p less than 0.0001, analysis of variance) and remained increased thereafter. Adenosine was largely degraded to inosine (0 hours, 0.03 +/- 0.03; 6 hours, 0.88 +/- 0.56; p less than 0.001) and hypoxanthine (0 hours, 0.01 +/- 0.01; 6 hours, 0.15 +/- 0.09; p = 0.004). Measured levels of xanthine and uric acid were extremely low at all time intervals. Adenosine triphosphate levels were maintained at 1 hour (0 hours, 0.64 +/- 0.38; 1 hour, 0.67 +/- 0.45) but declined thereafter (6 hours, 0.21 +/- 0.21; 12 hours, 0.11 +/- 0.09; 24 hours, 0.04 +/- 0.03; p less than 0.0001). Levels of adenosine diphosphate (p = 0.007) and adenosine monophosphate (p less than 0.05) decreased to approximately 25% of original values by 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1991

Prolonged preservation with University of Wisconsin Solution.

Previous studies from this institution using human cell cultures have suggested that University of Wisconsin Solution may be preferred for prolonged cardiac storage. University of Wisconsin Solution (UWS) contains adenosine (5 mmole/liter) which could maintain adenine nucleotides better than other storage fluids. Human cardiomyocytes were isolated from left ventricular biopsies. Cells (seven to nine dishes/group) were rinsed of culture media and placed in one of four solutions: Stanford cardioplegia, phosphate-buffered saline, modified EuroCollins', or UWS. Metabolites were assessed using high-performance liquid chromatography (units = nmole/micrograms DNA) after 24 hr of storage at 0 degrees C and compared to baseline controls (BASE). Adenosine triphosphate (P less than 0.0001, ANOVA), adenosine diphosphate (P less than 0.0001), and adenosine monophosphate (P less than 0.01) decreased with each solution compared to BASE but were maintained best with UWS (P less than 0.05). Adenosine increased in the UWS cells only (BASE, 0.029 +/- 0.118; UWS, 1.836 +/- 1.110; P less than 0.0001, ANOVA). Adenosine in the UWS cells was largely degraded to inosine (UWS, 1.013 +/- 0.779; BASE, 0.034 +/- 0.032; P less than 0.0001) and hypoxanthine (UWS, 0.124 +/- 0.091; BASE, 0.005 +/- 0.005; P less than 0.001). University of Wisconsin Solution does preserve adenine nucleotides better than other storage fluids and may improve the clinical results of cardiac transplantation.

Adenine Nucleotides↗
PubMed1991

Current risk of coronary bypass for unstable angina.

The risk associated with surgical revascularization for unstable angina is critically dependent upon the clinical presentation of the patient. For this study, between January 1982 and December 1987, clinical, angiographic, operative and hospital outcome data were collected prospectively for 6539 patients undergoing surgery for unstable angina. Urgent surgery was performed in 1523 patients (23.3%), while 5016 (76.7%) underwent semielective revascularization. The mean age was 58.9 +/- 9.2 years and 805 patients (12.3%) were aged 70 years or above. The male:female ratio was 3.6:1. Depressed left ventricular function (left ventricular ejection fraction less than 40%) was present in 27.2% of the population. Preoperative myocardial infarction (within 30 days of surgery) had occurred in 588 patients (9.0%). Operative mortality was 4.6% (301 deaths). Stepwise logistic regression analysis was performed to determine the independent predictors of operative mortality. The following variables were selected in descending order: urgent surgery (P less than 0.001), coronary reoperation (P less than 0.001), depressed left ventricular (P less than 0.001), female gender (P less than 0.001), increasing age (P less than 0.001), left main stenosis (P = 0.002), and preoperative myocardial infarction (P less than 0.001). Predicted operative mortality varied between 0.5 +/- 0.3% and 82.6 +/- 12.7%. The most important determinant for patients with a preoperative myocardial infarction was left ventricular dysfunction, whereas urgent surgery for unstable angina was the most important risk variable in those without preoperative necrosis.

Adult↗
PubMed1991

Technical aspects of warm heart surgery.

Intermittent hypothermic cardioplegia has been adopted as the method of choice for myocardial protection by most surgeons. The most important aspect of this protection is believed to be adequate hypothermia. An alternative technique has been developed, based on the principles of electromechanical arrest and normothermic aerobic perfusion using continuous warm blood cardioplegia. With this method of myocardial protection the heart is maintained at 37 degrees C throughout the operative procedure. The specific technical aspects used shall be described in detail.

Aortic Valve↗