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Biomedical subjects

J E Nordrehaug

Publications and source records attributed to J E Nordrehaug.

At least 19 recordsLinked to original sources

Sustained retention of tetradecylthioacetic acid after local delivery reduces angioplasty-induced coronary stenosis in the minipig.

OBJECTIVE: The sulfur containing tetradecylthioacetic acid (TTA) has a profound effect on lipid metabolism and may also exert antioxidant and anti-inflammatory actions and thereby counteract coronary stenosis after angioplasty balloon injury. This study examined the possible modulatory effects of TTA, delivered locally, on coronary stenosis in minipigs and the underlying mechanisms of action. METHODS: Coronary balloon angioplasty injury using an oversized balloon was performed to 40 coronary arteries (20 minipigs, Sus Scrofa, Gammelsroed) followed by delivery of placebo or TTA via a local drug delivery balloon catheter. TTA was radiolabelled in four pigs. Quantitative coronary angiography and intracoronary ultrasound (ICUS) were performed before and after injury, and after 4 weeks of follow-up. The arteries were examined with histomorphometry. The antioxidant and anti-inflammatory effects of TTA were examined on LDL oxidation and stimulated release of interleukin (IL)-2 and IL-10 in human peripheral blood mononuclear cells (PBMC), respectively. RESULTS: Radioactive TTA was present in the coronary wall after 4 weeks. Angiographic minimal luminal diameter (mean+/-S.E.M.) in the placebo and TTA group was 1.3+/-0.1 vs. 2.2+/-0.2 mm (P<0.01) at follow-up, stenosis rate was 55 and 20% (P<0.01). Remodeling was -0.56+/-0.12 in the TTA group and -1.28+/-0.09 in the placebo group (P<0.01). TTA significantly prolonged the lag time of LDL oxidation. In phytohemagglutinin stimulated PBMC, TTA significantly decreased IL-2 levels and increased IL-10 levels suggesting a marked anti-inflammatory net effect. CONCLUSIONS: Local delivery of TTA reduces coronary artery stenosis after PTCA as assessed by both angiographic, histomorphometric and ICUS examinations by influencing vessel remodeling rather than intimal hyperplasia. The underlying mechanism(s) seem to involve antioxidant and anti-inflammatory effects of this fatty acid analogue.

Administration, Topical↗

Tetradecylthioacetic acid reduces stenosis development after balloon angioplasty injury of rabbit iliac arteries.

BACKGROUND: tetradecylthioacetic acid (TTA) is a synthetic long-chain fatty acid analogue that inhibits the oxidative modification of low-density lipoprotein particles in vitro. We examined the influence of TTA on the arterial wall response after balloon angioplasty injury in a rabbit iliac model. METHODS AND RESULTS: 14 rabbits were randomized to receiving either TTA fatty acids 800 mg daily perorally (weight 3.6+/-0.1 kg) or to normal diet (weight 3.5+/-0.5 kg, P=NS). Angioplasty was performed via right carotidotomy on both iliac arteries using an oversized balloon catheter, the TTA group being pretreated for 3 weeks. After angioplasty, the lumen diameter was 2.37+/-0.18 versus 2.36+/-0.13 mm for the TTA and control groups, respectively (P=NS). At 10 weeks follow-up angiography, minimal luminal diameter was 1.64+/-0.27 versus 1.13+/-0.52 mm for the TTA and control groups respectively (P<0.05). Histomorphometry did not show significant differences in intimal hyperplasia between the two groups (maximal intimal thickness 0.22+/-0.04 versus 0.19+/-0.10 mm, P=NS and intimal area 0.32+/-0.12 versus 0.36+/-0.23 mm(2), P=NS for the TTA and the control groups, respectively). In the heart, the sum of the n-3 fatty acids was 8.9+/-2.7 in the TTA group versus 4.3+/-0.2 mol% in the control group (P<0.05). The anti-inflammatory fatty acid index, calculated as (22:5 n-3+22:6 n-3+20:3 n-6)/20:4 n-6, was 0.76+/-0.10 vs. 0.25+/-0.03 for the TTA and control groups, respectively (P<0.05). In vitro TTA (100 microM) reduced the proliferation of human smooth muscle cell by more than 50%. CONCLUSION: treatment with TTA is associated with positive arterial remodeling after angioplasty injury. The significance of the in vitro inhibition of human smooth muscle cell proliferation needs to be further elucidated.

Angioplasty, Balloon↗

Myocardial laser revascularization in the year 2000 as seen by a Norwegian specialist panel. The process of evaluating and implementing new methods in clinical practice.

OBJECTIVE: In Norway "Transmyocardial laser revascularization" as a routine method was prohibited by the Ministry of Health in 1995 due to lacking evidence of treatment effect and concerns about procedural morbidity and mortality. In 1999 Norwegian health authorities asked for a re-evaluation of the method based on a systematic review of literature. METHODS: Medline and Embase were searched and a total of 267 articles were identified. Publications were classified by an expert panel according to type of study and importance for the project. RESULTS: Based on the literature review the panel concluded that heart laser treatment does not have a life-saving effect, nor does it improve myocardial function. However, the method has a considerable short-term symptomatic effect, the mechanism of which is not understood. Neoangiogenesis, denervation and placebo may play a role. Based on the report the Norwegian health authorities recommended use of this method be restricted to scientific trials only. CONCLUSIONS: Based on a systematic literature review it was concluded that the only documented effect of heart laser treatment is symptom relief, the mechanism for which is unclear. It could partly or totally be a placebo effect. A conflict of interest may arise when new technologies are to be implemented in health care. The communication between professionals evaluating scientific results and decision makers is challenging. Quality assurance of this process may be obtained by use of expert panels working under the auspices of an official institution.

Heart Diseases↗

Long-term retention of a novel antioxidant sulphur-substituted fatty acid analogue after local delivery in porcine coronary arteries.

OBJECTIVE: Antioxidants have been suggested to reduce restenosis after balloon angioplasty. A novel sulphur-containing fatty acid, tetradecylthioacetic acid (TTA), with antioxidant properties, is efficiently incorporated into cellular phospholipids. We have determined the uptake and retention of TTA after local coronary artery delivery in 20 pigs. DESIGN: Radiolabelled TTA was delivered to 40 main coronary arteries via a multiporous coronary angioplasty balloon catheter inflated before, after, or without overstretch vessel injury. The animals were killed at intervals of up to 6 weeks post-procedure. The radioactivity of the tissue sections was determined as nmol TTA/g tissue. RESULTS: Concentrations of TTA in the coronary arteries were 1.84 +/- 0.45 nmol/g up to 24 h, 1.50 +/- 0.96 nmol/g at 2 weeks, 0.22 +/- 0.11 nmol/g at 4 weeks and a trace was present at 6 weeks (p-value for trend <0.01). The arterial wall uptake at the delivery site was higher than distal to delivery (1.84 +/- 0.37 vs 0.55 +/- 0.13 nmol/g, p = 0.006) and perivascular fat (p < 0.01) but not higher than in the myocardium. Infusion before, after or without vessel injury was not important for tissue concentration. CONCLUSIONS: After local coronary artery delivery, the antioxidant TTA is taken up by the arterial wall in which it is retained for at least 4 weeks.

Angioplasty, Balloon, Coronary↗

Plasma total homocysteine and cardiovascular and noncardiovascular mortality: the Hordaland Homocysteine Study.

BACKGROUND: Few population-based studies have assessed relations between plasma or serum total homocysteine (tHcy) and all-cause mortality. OBJECTIVE: Our goal was to study associations between plasma tHcy and all-cause, cardiovascular, and noncardiovascular mortality. DESIGN: This was a prospective cohort study of 2127 men and 2639 women aged 65-67 y in 1992-1993 when they were recruited as part of a population-based national cardiovascular screening program carried out in Hordaland County, Norway. RESULTS: During a median of 4.1 y of follow-up, 162 men and 97 women died. A strong relation was found between plasma tHcy and all-cause mortality. The association was highly significant for noncardiovascular and for cardiovascular causes of death. In a comparison of individuals having tHcy concentrations of 9.0-11.9, 12.0-14.9, 15.0-19.9, or > or = 20 micromol/L with individuals having a tHcy concentration < 9 micromol/L, adjusted mortality ratios were 1.4, 1.9, 2.3, and 3.6 (P for trend = 0.0002) for noncardiovascular and 1.3, 2.1, 2.6, and 3.5 (P for trend = 0.0002) for cardiovascular causes of death. A tHcy increment of 5 micromol/L was associated with a 49% (95% CI: 28%, 72%) increase in all-cause mortality, a 50% (95% CI: 21%, 85%) increase in cardiovascular mortality (121 deaths), a 26% (95% CI: -2%, 63%) increase in cancer mortality (103 deaths), and a 104% (95% CI: 44%, 289%) increase in noncancer, noncardiovascular mortality (33 deaths). CONCLUSION: Plasma tHcy is a strong predictor of both cardiovascular and noncardiovascular mortality in a general population of 65-72-y-olds. These results should encourage studies of tHcy in a wider perspective than one confined to cardiovascular disease.

Adult↗

Early mobilization after protamine reversal of heparin following implantation of phosphorylcholine-coated stents in totally occluded coronary arteries.

Immediate removal of the femoral artery sheath after coronary angioplasty may allow rapid mobilization and reduces the number of in-hospital days. We studied the early and 1-month clinical and angiographic follow-up of patients having heparin reversed with protamine after implantation of phosphorylcholine-coated metal (Divysio) stents, followed by removal of the femoral artery sheath. Fifty patients (37 men, mean age 59 +/- 10 years) with stable angina pectoris and a single totally occluded artery (1 unprotected left main stem, 15 left anterior descending, 11 left circumflex, 23 right) underwent coronary angioplasty. Antithrombotic medication was salicylic acid 75 to 160 mg before, heparin bolus 7,500 IU during, and protamine sulfate 25 mg and oral ticlopidine 250 mg after the procedure. Angiography was performed after 30 minutes and at 1 month. The mean number of stents was 1.4 +/- 0.6/lesion, with a mean final diameter of 2.69 +/- 0.40 mm. One stent thrombus was detected after 30 minutes and was treated with balloon dilatation. One patient underwent emergency bypass surgery for non-stent-related problems. Forty-six patients were mobile after 5 hours, and 2 after >5 hours. At 1 month there had been no major coronary end points, rehospitalizations, groin bleeding, or more thrombi. One episode of transient pulmonary edema occurred after protamine injection. Thirty-eight patients (79%) had no angina at 1 month, maximal bicycle exercise capacity increased from 128 +/- 42 to 160 +/- 45 W (p <0.05), and left ventricular ejection fraction increased from 63% to 68% (p <0.05). Thus, reversal of heparin with protamine sulfate after implantation of a phosphorylcholine-coated stent enables early mobilization. This approach seems safe in patients with 1 -vessel total occlusions and angioplasty could be performed as an outpatient procedure.

Angioplasty, Balloon, Coronary↗

Cardiac biochemical markers after cardioversion of atrial fibrillation or atrial flutter.

BACKGROUND: Cardioversion or defibrillation of cardiac arrhythmias is often necessary in acutely ill cardiac patients. The electrical current may cause elevation of biochemical markers used to diagnose acute myocardial infarction. Therefore it is important to find cardiac markers with high specificity for myocardial necrosis. The purpose of this study was to assess the effects of elective cardioversion of atrial fibrillation or flutter on troponin T and I among conventional markers in patients with no evidence of acute ischemia. METHODS AND RESULTS: Fifty-seven consecutive patients underwent 1 to 4 direct current shocks (mean cumulative energy 407 J, range 100 to 920 J) under general anesthesia. At baseline, all had normal troponin levels; 50 patients (mean age 68 years, range 33 to 84 years) had normal cardiac enzymes and were included in the final analysis. Blood samples were drawn at baseline, and 1 to 2, 6 to 8, and 20 to 24 hours after cardioversion. The troponin levels were unaffected by cardioversion in all patients, whereas creatine kinase and myoglobin increased more than 10-fold. Creatine kinase MB mass and aspartate aminotransferase were above reference limits in 18% and 24% of patients, respectively, 20 to 24 hours after cardioversion. There was a significant association between elevated creatine kinase, myoglobin, and creatine kinase MB levels with cumulated energy delivered as well as when possible confounders such as age and sex were adjusted for. High international normalized ratio with warfarin use was associated with increased levels of creatine kinase, aspartate aminotransferase, lactate dehydrogenase, and myoglobin. CONCLUSIONS: The increase of conventional biochemical markers after direct current cardioversion is positively associated with cumulative energy delivered and international normalized ratio (INR) values; neither influences levels of the cardiac troponins.

Adult↗

Doppler-echocardiographic findings in professional divers.

To determine if professional diving leads to morphologic and/or functional cardiologic changes, Doppler-echocardiography was performed in 20 professional saturation divers (average 15 yr diving experience) and compared to 20 control persons (policemen) who were matched for age (35-45 yr) and number and duration of training sessions. The policemen were taller than the divers, therefore the echocardiographic dimensions but not the functional variables were normalized for body surface area. The groups were comparable for resting and maximal treadmill exercise heart rate, blood pressure, oxygen uptake, and respiratory exchange ratio. Thickness of left ventricular (LV) anterior and posterior wall in end diastole and end systole, and left ventricular mass were similar in the two groups. The systolic functional parameters, LV ejection fraction, and fractional shortening were on average normal in both groups, although one of the divers had low values. Their LV chamber dimensions, wall thickness, diastolic parameters, and exercise capability were normal. The diastolic functional parameters were equal in the two groups. These results suggest that professional divers have normal size and mass of the heart, no diastolic functional changes, and a normal average systolic function.

Adult↗

Serotonin is associated with coronary artery disease and cardiac events.

BACKGROUND: Blood platelets are related to coronary atherogenesis. Platelets secrete serotonin (5-hydroxytryptamine) which has several effects on the vascular wall and promotes thrombogenesis, mitogenesis, and proliferation of smooth muscle cells. Serotonin may therefore be one of the factors involved in the development of coronary artery disease (CAD). We have assessed serotonin among conventional predictors for CAD in patients undergoing coronary angiography for chest pain or clinically suspected angina pectoris. METHODS AND RESULTS: Of 121 consecutive male patients (mean age 65, range 41 to 90 years) undergoing angiography, 96 had coronary artery stenosis and 25 had normal angiograms. Serotonin, blood platelet count, and conventional biochemical risk factors for CAD were determined in the morning the day before the angiography. High serotonin (cut-point 1000 nmol/L) was significantly associated with CAD with an odds ratio (OR) of 3.4 (95% confidence interval 1.2 to 9. 8). The corresponding OR for smokers was 4.8 (1.9 to 12.2); hypercholesterolemia (>7 mmol/L), 2.9 (1.1 to 7.6); high platelet count (cut-point 325 10(9)/L), 3.0 (1.0 to 9.5); and family history of heart disease, 2.3 (1.0 to 5.2). After adjustment with conventional risk factors, the OR for CAD was 3.8 (1.1 to 13.1), comparing high and low values of serotonin. The relation between serotonin and CAD was strengthened only when patients <70 years (n=82) were included in the analysis. In this age group, the occurrence of cardiac events during a mean of 3.7 years of follow-up was significantly associated with high serotonin values. CONCLUSIONS: The study suggests that serotonin is associated with coronary artery disease and occurrence of cardiac events, particularly in younger age groups. This association seems to persist after adjustment for conventional risk factors.

Adult↗

Phosphorylcholine-coated metallic stents in rabbit iliac and porcine coronary arteries.

The arterial wall reaction to phosphorylcholine-coated metal stents was examined in rabbits and pigs. Compared to non-coated stents, no significant difference was found by angiography and histology. We conclude that although phosphorylcholine-coating does not provoke arterial neointima formation or decrease luminal diameter compared to stainless steel stents, the coating does not seem to reduce restenosis.

Angiography↗

Ketorolac (Toradol) as an analgesic in swine following transluminal coronary angioplasty.

Post-procedure pain is a common complication in swine following survival angioplastic procedures. Ketorolac and buprenorphine have been used to control pain in these animals. Time from completion of procedure-extubation to onset of feeding was used as an indicator for analgesic effect. The onset of feeding following extubation occurs within 6 to 20 h in animals given ketorolac compared to 30 plus hours in animals given buprenorphine.

Analgesics, Non-Narcotic↗

Plasma homocysteine levels and mortality in patients with coronary artery disease.

BACKGROUND: Elevated plasma homocysteine levels are a risk factor for coronary heart disease, but the prognostic value of homocysteine levels in patients with established coronary artery disease has not been defined. METHODS: We prospectively investigated the relation between plasma total homocysteine levels and mortality among 587 patients with angiographically confirmed coronary artery disease. At the time of angiography in 1991 or 1992, risk factors for coronary disease, including homocysteine levels, were evaluated. The majority of the patients subsequently underwent coronary-artery bypass grafting (318 patients) or percutaneous transluminal coronary angioplasty (120 patients); the remaining 149 were treated medically. RESULTS: After a median follow-up of 4.6 years, 64 patients (10.9 percent) had died. We found a strong, graded relation between plasma homocysteine levels and overall mortality. After four years, 3.8 percent of patients with homocysteine levels below 9 micromol per liter had died, as compared with 24.7 percent of those with homocysteine levels of 15 micromol per liter or higher. Homocysteine levels were only weakly related to the extent of coronary artery disease but were strongly related to the history with respect to myocardial infarction, the left ventricular ejection fraction, and the serum creatinine level. The relation of homocysteine levels to mortality remained strong after adjustment for these and other potential confounders. In an analysis in which the patients with homocysteine levels below 9 micromol per liter were used as the reference group, the mortality ratios were 1.9 for patients with homocysteine levels of 9.0 to 14.9 micromol per liter, 2.8 for those with levels of 15.0 to 19.9 micromol per liter, and 4.5 for those with levels of 20.0 micromol per liter or higher (P for trend=0.02). When death due to cardiovascular disease (which occurred in 50 patients) was used as the end point in the analysis, the relation between homocysteine levels and mortality was slightly strengthened. CONCLUSIONS: Plasma total homocysteine levels are a strong predictor of mortality in patients with angiographically confirmed coronary artery disease.

Adult↗

Clinical applicability of creatine kinase MB mass and the electrocardiogram versus conventional cardiac enzymes in the diagnosis of acute myocardial infarction.

We compared creatine kinase MB (CK-MB) mass and total creatine kinase (CK) sampled three times daily with conventional cardiac enzymes. The influence of the electrocardiogram (ECG) on admission, frequency of blood sampling, thrombolytic therapy, different upper reference limits of the biochemical markers and duration of symptoms were assessed in 100 consecutive patients with suspected AMI of whom 63 were confirmed according to WHO criteria. Early sensitivity but not specificity of CK-MB mass, with and without ECG, for cut points <8 microg/l was significantly better than total CK sampled frequently. The sensitivity of ECG on admission (52%) was significantly improved by CK-MB analysis (79%) but not by total CK. Duration of symptoms (range of means 3.5-9 h) or thrombolytic treatment had no influence on the sensitivity and specificity of CK-MB mass. In AMI with inconclusive ECG, CK-MB mass performed best of the markers with a sensitivity of 70% versus 17% of total CK (P<0.001) on admission. CK-MB mass was also elevated in 8 patients classified conventionally as unstable angina. We conclude that CK-MB mass is a more useful marker of AMI during the first 16 h of chest pain than frequently sampled total CK, ECG and conventional cardiac enzymes.

Adult↗

The shortening fraction of myocardial fibers and its layered distribution, as derived from cine-MR imaged left ventriculograms. An approach for evaluating globar left ventricular function.

PURPOSE: To evaluate the mean shortening fraction and its SD through the wall calculated from multiple cine-MR views, as an estimate of left ventricular globar function. MATERIAL AND METHODS: The average myocardial fiber shortening fraction was calculated by means of a simple truncated ellipsoid nested shell model. Left ventricular parameters, acquired by cine-MR imaging, from 20 healthy volunteers served as input. Fiber angles, ventricular torsion and a gradient increase in wall thickening from epicard to endocard were part of the model. RESULTS: The average fiber shortening fraction was 0.203 (0.158-0.246) +/- 0.021 diastolic lengths. It varied only moderately with variations in fiber angle values and not at all when the torsion angles were varied within physiological limits. The average shortening fraction correlates well with the systolic increase in chamber oblonguity (k = 0.837), with the ejection fraction (k = 0.877), and even better with the calculated wall thickening (k = 0.973). The average epicardial shortening fraction 0.169 (0.142-0.202) +/- 0.016 increased gradually through the wall to the endocardial value 0.250 (0.212-0.290) +/- 0.024. The increase in chamber length-width ratio from diastole to systole reduced the SD of the shortening fraction through the wall layers to a minimum. CONCLUSION: The fiber shortening fraction expresses the layered contraction of the myocardial wall, the wall thickening, and also the endocardial wall motion. The ejection fraction expresses only the latter. The shortening fraction and its SD through the wall may prove a valuable additional tool for estimating ventricular globar function.

Adult↗

Coffee consumption and plasma total homocysteine: The Hordaland Homocysteine Study.

The health consequences of coffee drinking remain controversial. We report on an association between coffee consumption and the concentration of total homocysteine (tHcy) in plasma, a risk factor for cardiovascular disease and for adverse pregnancy outcome. The study population consisted of 7589 men and 8585 women 40-67 y of age and with no history of hypertension, diabetes, ischemic heart disease, or cerebrovascular disease. They were recruited from Hordaland county of western Norway in 1992-1993. Daily use of coffee was reported by 89.1% of the participants, of whom 94.9% used caffeinated filtered coffee. There was a marked positive dose-response relation between coffee consumption and plasma tHcy, which was stronger than the relation between coffee and total serum cholesterol. In 40-42-y-old men, mean tHcy was 10.1 mumol/L for nonusers and 12.0 mumol/L for drinkers of > or = 9 cups of coffee/d. Corresponding tHcy concentrations in 40-42-y-old women were 8.2 and 10.5 mumol/L, respectively. Although coffee drinking was associated with smoking and lower intake of vitamin supplements and fruit and vegetables, the coffee-tHcy association was only moderately reduced after these variables were adjusted for. The combination of cigarette smoking and high coffee intake was associated with particularly high tHcy concentrations. A strong inverse relation between tea and tHcy concentration in univariate analysis was substantially attenuated after smoking and coffee drinking were adjusted for. The results of the present report should promote future studies on tHcy as a possible mediator of adverse clinical effects related to heavy coffee consumption.

Adult↗