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Biomedical subjects

D van Dijk

Publications and source records attributed to D van Dijk.

12 recordsLinked to original sources
PubMed2005

Jugular bulb desaturation during coronary artery surgery: a comparison of off-pump and on-pump procedures.

BACKGROUND: Conventional coronary artery bypass surgery has been associated with cerebral injury attributed to cardiopulmonary bypass (CPB) and surgical manipulation of the ascending aorta. Off-pump coronary artery surgery avoids these factors and could prevent cerebral injury. However, moving the heart from its natural position affects the circulation and could compromise cerebral oxygenation and perfusion. We set out to compare episodes of poor global cerebral oxygenation, defined as a jugular bulb saturation less than 50%, between patients randomized to off-pump or (conventional) on-pump coronary artery surgery. METHODS: One hundred and eighty-seven patients were assigned randomly to off-pump or on-pump coronary artery surgery. Oxygen saturation in the jugular bulb (SjO2) was measured during revascularization of the three main coronary vessels in the off-pump group, and at the start of CPB, before rewarming, and after rewarming in the on-pump group. We compared samples with jugular bulb with desaturation (SjO2) < or = 50%) between treatment groups. RESULTS: One hundred and seventy-five patients (81 in the off-pump group [93%] and 94 in the on-pump group [94%]) had complete jugular oxygen saturation data. Thirty-nine patients in the off-pump group (48%) and 25 patients in the on-pump group (27%) had one or more samples with desaturation during revascularization or CPB (odds ratio after adjustment for other factors, 0.39; 95% confidence interval, 0.21-0.73, P<0.01). CONCLUSION: Jugular bulb desaturation occurs more frequently during off-pump coronary artery surgery than during conventional coronary artery surgery.

Adult↗
PubMed2005

The incidence of cognitive decline after (not) undergoing coronary artery bypass grafting: the impact of a controlled definition.

BACKGROUND: After coronary artery bypass grafting (CABG), 20-30% of patients are reported to suffer from cognitive decline. Studies reporting these high incidences, however, have not included an appropriate control group. METHODS: We repeatedly administered a series of neuropsychological tests to 112 healthy middle-aged volunteers not undergoing surgery, and applied two widely used definitions of cognitive decline to their test results. In addition, we re-analysed the neuropsychological test data of 281 CABG patients with a definition of cognitive decline that takes into account the natural variability of test performance that was found in the volunteers. RESULTS: Three months after their first assessment, 14-28% of the volunteers suffered from cognitive decline according to the definitions of cognitive decline after CABG. Using the controlled definition of cognitive decline that takes the natural variability in test performance into account, we found that only 7.7% of the CABG patients suffered from cognitive decline at 3 months after their operation. CONCLUSION: These data suggest that the incidence of cognitive dysfunction after CABG has previously been greatly overestimated.

Aged↗
PubMed2004

Association between early and three month cognitive outcome after off-pump and on-pump coronary bypass surgery.

OBJECTIVE: To describe the association between cognitive outcome in the first postoperative week and that at three months after both off-pump and on-pump coronary bypass surgery, and to make a direct comparison of early cognitive outcome after off-pump versus on-pump surgery. DESIGN: Randomised trial with an additional prediction study within the two randomised groups. SETTING: Three centres for heart surgery in the Netherlands. PATIENTS: 281 patients, mean age 61 years. INTERVENTIONS: Participants were randomly assigned to off-pump or on-pump coronary bypass surgery. MAIN OUTCOME MEASURES: Cognitive outcome, assessed by psychologists who administered neuropsychological tests one day before and four days and three months after surgery. A logistic regression model was used to study the predictive association between early cognitive outcome, together with eight clinical variables, and cognitive outcome after three months. RESULTS: Cognitive outcome in the first week after surgery was determined for 219 patients and was a predictor of cognitive decline after three months. This association was stronger in on-pump patients (odds ratio (OR) 5.24, p < 0.01) than in off-pump patients (OR 1.80, p = 0.23). Early decline was present in 54 patients (49%) after off-pump surgery and 61 patients (57%) after on-pump surgery (OR 0.73, p = 0.25). CONCLUSIONS: In patients undergoing first time coronary bypass surgery, early cognitive decline predicts cognitive outcome after three months. Early cognitive decline is not significantly influenced by the use of cardiopulmonary bypass.

Cognition Disorders↗
PubMed2002

Effect of rewarming speed during hypothermic cardiopulmonary bypass on cerebral pressure-flow relation.

BACKGROUND: Cerebral blood flow is less dependent on arterial blood pressure during hypothermic cardiopulmonary bypass (CPB) compared to warm CPB. Fast rewarming has a more pronounced effect on cognitive performance in the elderly and causes an increased arterio-jugular oxygen content difference. We studied the effect of rewarming and rewarming speed on cerebral pressure-flow relation in adult patients undergoing elective coronary artery bypass surgery with mild hypothermic CPB. METHODS: Fifty patients were randomly assigned to either a slow rewarming strategy (0.24 degrees C/min) or a fast rewarming strategy (0.5 degrees C/min). Cerebral pressure-flow relation was assessed by a transcranial Doppler derived index for cerebral pressure-flow relation (Pressure-flow Index, PFI). The effect of rewarming speed on cerebral pressure-flow relation was assessed by comparing the absolute PFI value after rewarming between the two treatment groups. RESULTS: The mean PFI decreased significantly from 0.73 (standard deviation: 0.28) before rewarming to 0.54 (0.35) after rewarming in the slow rewarming group and from 0.63 (0.29) to 0.48 (0.30) in the fast rewarming group. Absolute PFI after rewarming was not significantly different (mean PFI difference = 0.06; 95% CI = - 0.13; 0.26) between both rewarming strategies. CONCLUSION: Rewarming from mild hypothermic CPB might result in pressure-dependent cerebral blood flow velocity but rewarming speed did not aggravate the effect of rewarming on pressure-flow dependency.

Blood Flow Velocity↗
PubMed2001

Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study.

BACKGROUND: The use of cardiopulmonary bypass during coronary artery bypass surgery (CABG) has been associated with substantial morbidity. The recent introduction of cardiac stabilizers facilitates CABG without cardiopulmonary bypass (off-pump CABG), but it is unknown whether cardiac outcome after off-pump surgery is similar to that for the on-pump procedure. METHODS AND RESULTS: In a multicenter trial, 281 patients (mean age 61 years, SD 9 years) were randomly assigned to off-pump or on-pump CABG. In-hospital results and cardiac outcome and quality of life after 1 month are presented. Cardiac outcome was defined as survival free of stroke, myocardial infarction, and coronary reintervention. The mean numbers of distal anastomoses per patient were 2.4 (SD 1.0) and 2.6 (SD 1.1) in the off-pump and on-pump groups, respectively. Completeness of revascularization was similar in both groups. Blood products were needed during 3% of the off-pump procedures and 13% of the on-pump procedures (P<0.01). Release of creatine kinase muscle-brain isoenzyme was 41% less in the off-pump group (P<0.01). Otherwise, no differences in complications were found postoperatively. Off-pump patients were discharged 1 day earlier. At 1 month, operative mortality was zero in both groups, and quality of life had improved similarly. In both groups, 4% of the patients had recurrent angina. The proportions of patients surviving free of cardiovascular events were 93.0% in the off-pump group and 94.2% in the on-pump group (P=0.66). CONCLUSIONS: In selected patients, off-pump CABG is safe and yields a short-term cardiac outcome comparable to that of on-pump CABG.

Cardiopulmonary Bypass↗
PubMed2000

The Octopus Study: rationale and design of two randomized trials on medical effectiveness, safety, and cost-effectiveness of bypass surgery on the beating heart.

The Octopus Study consists of two multicenter randomized clinical trials in which coronary artery bypass grafting on the beating heart (off-pump CABG) using the Utrecht Octopus Method is compared to intracoronary stent implantation and conventional CABG. The primary endpoint in the comparison of off-pump CABG versus stent implantation (OctoStent Trial) is medical effectiveness (i.e., absence of reintervention and major adverse cardiac and cerebrovascular events at 1 year after treatment). The primary endpoint in the comparison of off-pump CABG versus conventional CABG (OctoPump Trial) is cerebral safety (i.e., absence of cognitive deficits and cerebrovascular events at 3 months after treatment). Secondary endpoints in both trials include presence and severity of angina, quality of life, exercise capacity, and cost-effectiveness. A total of 560 patients will be enrolled. A random sample of 210 patients will undergo repeat angiography at 1 year to assess angiographic restenosis rate and graft patency. Including 1-year follow-up, the study will last for 3 years. Control Clin Trials 2000;21:595-609

Angioplasty, Balloon, Coronary↗
PubMed2000

Neurocognitive dysfunction after coronary artery bypass surgery: a systematic review.

OBJECTIVE: Substantial, albeit scattered, evidence suggests that coronary artery bypass grafting may impair cognitive function. As methods and definitions differ greatly across studies, the reported incidence of cognitive decline after coronary bypass surgery varies widely as well. The aim of the present study was to systematically review those studies on cognitive decline that are relatively comparable and meet with certain quality criteria. METHODS: Four electronic databases and the references of several abstract books and earlier reviews were used to identify relevant literature. Stringent criteria, based in part on the 1994 consensus meeting on assessment of neurobehavioral outcomes after cardiac surgery, were used to assess the studies that were found. In total, 256 different titles were found, of which 23 met with the formulated selection criteria. RESULTS: Twelve cohort studies and eleven intervention studies were evaluated. A pooled analysis of six highly comparable studies yielded a proportion of 22.5% (95% confidence interval, 18.7%-26.4%) of patients with a cognitive deficit (a decrease of at least 1 standard deviation in at least two of nine or ten tests) 2 months after the operation. CONCLUSIONS: Neurocognitive dysfunction is a frequently occurring complication of coronary artery bypass grafting. The etiologic contribution of cardiopulmonary bypass to this complication will remain unclear until a randomized trial that directly compares off-pump and on-pump bypass surgery is carried out.

Cardiopulmonary Bypass↗
PubMed1999

Embracing the heart: perioperative management of patients undergoing off-pump coronary artery bypass grafting using the octopus tissue stabilizer.

OBJECTIVE: To describe hemodynamic alterations during coronary artery bypass grafting (CABG) without extracorporeal circulation using the Octopus Tissue Stabilizer, and to describe the two anesthetic management protocols based on either general anesthesia with opioids (34 patients) or general anesthesia with high thoracic epidural anesthesia (TEA; 66 patients). DESIGN: A prospective observational report. SETTING: An academic university heart center. PARTICIPANTS: First 100 patients undergoing CABG using the Octopus Tissue Stabilizer. INTERVENTIONS: None. MAIN RESULTS: Current management provided satisfactory results in preventing hypoperfusion of the heart and inadequate systemic circulation without the use of major pharmacologic interventions. Movement of the heart to reach the target site of anastomosis caused hemodynamic alterations. These could easily be corrected by anesthetic interventions, such as fluid load and low doses of inotropes. High TEA allows earlier extubation compared with the opioid anesthesia technique (0.9 v 4.5 hours). Perioperative management and the incidence of postoperative complications did not differ between anesthetic techniques. Major complications, such as death, intraoperative myocardial infarction, and stroke, did not occur. CONCLUSION: Both anesthetic protocols are safe and effective in handling these patients. Off-pump CABG surgery requires anesthetic interventions because hemodynamic alterations are caused by the presentation of the heart to the surgeon. The complication rate is low but needs to be evaluated, compared with conventional CABG, in a prospective randomized study. High thoracic epidural anesthesia allows early recovery, but improved outcome could not be proved in this patient group.

Adjuvants, Anesthesia↗
PubMed1999

The QA pressure measurement system: an accuracy and reliability study.

OBJECTIVE: The main purpose of this study was to determine the accuracy and reliability of the Queen Alexandra Pressure Measurement System (QA PMS). Furthermore, we examined whether there were significant differences in measured pressures of the buttock area during sitting between normal subjects and spinal cord injured (SCI) patients. DESIGN: Accuracy (calibration) and reliability (test-retest) study. SETTING: The spinal cord unit of Tertiary Care Centre 'De Hoogstraat' in Utrecht, The Netherlands. PATIENTS: A convenience sample of 16 SCI patients and 15 normal subjects. MAIN OUTCOME MEASURES: The accuracy was determined by using the Standard Error of the Mean (SEM, in mmHg). The Technical Error of Measurement (TEM, in mmHg) was calculated as measure for differences between two paired measurements. The reliability was determined by using an Intraclass Correlation Coefficient (ICC). Significant differences in measured pressures between both groups (P<0.05) were determined by using an unpaired (two sample) t-test. RESULTS: Accuracy (calibration): mean SEM=0.30 (+/-0.1) mmHg, indicating a high level of accuracy. Differences between two paired measurements: mean TEM calibration= 1.87 (+/-0.76) mmHg; mean TEM normal subjects=4.76 (+/-1.78) mmHg; mean TEM SCI patients=6.34 (+/-2.19) mmHg. Reliability: mean ICC(3,1) calibration=0.85 (95% CI=0.74 0.95); mean ICC(2.1) normal subjects=0.92 (95% CI=0.90 0.94); mean ICC(2.1) SCI patients=0.90 (95% CI=0.88 0.92). The normal subjects had significantly higher mean pressures (P=0.028) than the SCI patients (mean pressures 31.0 vs 28.5 mmHg), whilst the SCI patients had significantly higher peak-pressures (P=0.0000) than the normal subjects (mean peak-pressures: 134.1 vs 75.7 mmHg). CONCLUSIONS: The QA Pressure Measurement System has sufficient accuracy and good reliability as a measurement procedure. There are significant differences between the measured pressures of both groups: the significantly higher peak pressures of the SCI patients seem to be the most important.

Buttocks↗
PubMed1999

Wageningen Evaluating Programmes for Analytical Laboratories (WEPAL).

The paper describes three of the Wageningen Evaluating Programmes for Analytical Laboratories (WEPAL). These include the analyses of numerous compounds and elements and different parameters such as inorganic chemical composition, organic matter, polycyclic hydrocarbons (PAH), polychlorinated biphenyls (PCB), organochlorine pesticides, some herbicides, heavy metals, particle size, and so on in soil, sediment, compost, manure, and sludge. One programme includes the analysis of inorganic chemical composition, nutritional values, and selected vitamins and amino acids in plant samples. Finally, the paper describes how the results are reported and statistically evaluated.

Chemistry Techniques, Analytical↗
PubMed1995

Intravascular ultrasound image subtraction: a contrast enhancing technique to facilitate automatic three-dimensional visualization of the arterial lumen.

At 30 MHz, the intravascular ultrasound backscatter of blood confounds the discrimination of the lumen from the arterial wall. This study validates a subtraction method which creates a still-frame image with a sharp demarcation of the lumen. The method involves subtraction of consecutive images and 2D ensemble averaging of the absolute pixel values. Subtraction exploits the dynamic properties of flowing red blood cells. Three phantom arteries were used, with erythrocytes in their lumens and wall. For this reason, it was not possible, in one single original image, to discriminate the blood in the lumen from the phantom wall. Based on 26 consecutive original images, in the mean subtraction image contrast between lumen and phantom wall grey values increased eightfold from 10.9 (5.3-19.2) (mean and range) in the original image to 87.7 (73.6-107.0) (P < 0.001). A sufficiently large contrast increase to allow automatic segmentation was obtained by using five original images (0.3-s acquisition time) for any single mean subtraction image. Low blood flow velocities (down to 0.5 cm/s) did not alter this result. Automatic segmentation of the lumen allowed fast 3D reconstruction of the lumen in all three phantom arteries. In phantom arteries, the intravascular ultrasound image subtraction technique improved contrast between lumen and wall which enabled automated lumen segmentation and fast 3D visualization of both the lumen and defects in the wall.

Arteries↗