PubMed Health⌕ Search

Biomedical subjects

J Bosmans

Publications and source records attributed to J Bosmans.

At least 19 recordsLinked to original sources
PubMed2004

Methotrexate loaded SAE coated coronary stents reduce neointimal hyperplasia in a porcine coronary model.

OBJECTIVE: To evaluate the effect of stent based methotrexate delivery on neointimal hyperplasia. METHODS: Stainless steel coronary stents and biological polymer coated (SAE) stents were randomly implanted in coronary arteries of pigs with a stent to artery ratio of 1.1:1. The pigs were killed after five days (10 stents) or four weeks (20 stents). Second, stainless steel coronary stents were dip coated in a 10 mg/ml methotrexate-SAE polymer solution, resulting in a total load of 150 microg methotrexate/stent. SAE coated stents and methotrexate loaded stents were randomly implanted in porcine coronary arteries with a stent to artery ratio of 1.2:1 and followed up to four weeks. RESULTS: SAE coated stents and bare stents elicited a similar tissue response at five days. At four weeks, neointimal hyperplasia induced by the coated stents was less pronounced than with the bare stents (1.32 (0.66) v 1.73 (0.93) mm2, p > 0.05). In vitro drug release studies showed that 50% of the methotrexate was released in 24 hours, and all drug was released within four weeks. No impact on vascular smooth muscle cell proliferation or viability was observed in in vitro cell cultures. At four weeks the arteries with methotrexate loaded stents had decreased peristrut inflammation and neointimal hyperplasia (1.22 (0.34) v 2.25 (1.28) mm2, p < 0.01). CONCLUSIONS: SAE coating had an excellent biocompatibility with vascular tissue. Stent based delivery of methotrexate in the SAE coating effectively reduced neointimal hyperplasia in a porcine coronary stent model, potentially due to reduced peristrut inflammation.

Animals↗
PubMed2002

Combined endurance/resistance training reduces plasma TNF-alpha receptor levels in patients with chronic heart failure and coronary artery disease.

AIMS: Physical reconditioning of patients with chronic heart failure (CHF) improves exercise capacity and restores endothelial function and skeletal muscle changes. The effects of 4 months combined endurance/resistance exercise training on cytokines and cytokine receptors in patients with CHF were studied. In addition, changes in submaximal and maximal exercise performance were addressed. METHODS AND RESULTS: Twenty-three patients with stable CHF due to coronary artery disease (CAD, n=12) or idiopathic dilated cardiomyopathy (IDCM, n=11) were trained for 4 months. Blood sampling for measurement of plasma concentrations (ELISA) of interleukin (IL)-6, tumour necrosis factor (TNF)-alpha, soluble TNF receptor 1 (sTNFR1) and 2 (sTNFR2), as well as cardiopulmonary exercise testing were performed at baseline and after 4 months. Training induced a significant decrease in sTNFR1 (P=0.02) for the total population, and in both sTNFR1 (P=0.01) and sTNFR2 (P=0.02) concentrations for the CAD group only. IL-6 and TNF-alpha levels were not altered. Cytokine concentrations remained unchanged in an untrained age- and sex-matched control group. NYHA functional class, submaximal and maximal workrate were significantly improved in both patient groups. Oxygen uptake at the anaerobic threshold (P=0.002) and at peak exercise increased in the CAD patients only (P=0.008). CONCLUSION: Besides an overall beneficial effect on exercise capacity, combined endurance/resistance exercise training has an anti-inflammatory effect in patients with CHD and CAD.

Adult↗
PubMed1999

Determinants and prognostic implications of persistent ST-segment elevation after primary angioplasty for acute myocardial infarction: importance of microvascular reperfusion injury on clinical outcome.

BACKGROUND: Despite early recanalization of an occluded infarct artery, reperfusion at the level of the microcirculation may remain impaired owing to a process of microvascular reperfusion injury. METHODS AND RESULTS: Microvascular reperfusion injury was studied in 91 patients with acute myocardial infarction (AMI) by evaluation of the resolution of ST-segment elevation after successful PTCA. Impaired microvascular reperfusion, defined as the presence of persistent (>/=50% of initial value) ST-segment elevation (ST >/=50%) at the end of coronary intervention, was observed in 33 patients (36%) and was independently correlated with low systolic pressure on admission and high age. Patients >/=55 years of age with systolic pressures </=120 mm Hg were at high risk for development of impaired reperfusion compared with patients not meeting these criteria (72% versus 14%, P<0.001). Impaired microvascular reperfusion was associated with a more extensive infarction and worse clinical outcome at the 1-year follow-up: cardiac death rate, 15% versus 2% (ST >/=50% versus ST <50%, P=0.01); nonfatal MI rate, 9% versus 2% (P=0.1); and total major adverse cardiac event (MACE) rate, 45% versus 15% (P<0.005). ST >/=50% was the most important independent determinant of MACE with an adjusted risk ratio of 3.4. CONCLUSIONS: Impaired microvascular reperfusion, as evidenced by ST >/=50% after successful recanalization, occurs in more than one third of our AMI patients, especially in older patients with low systolic pressure. Its detrimental implications on clinical outcome reinforce the need to develop adjunctive agents that attenuate the process of reperfusion injury.

Aged↗
PubMed1999

Effect of stenting on coronary flow velocity reserve: comparison of coil and tubular stents.

OBJECTIVE: To determine whether coil stents are as effective as tubular stents in improving coronary flow velocity reserve (CFVR) after stent deployment. METHODS: Distal CFVR was measured with a 0. 014 inch Doppler guide wire before and after stenting in 33 patients. A coil stent was implanted in 16 patients and a tubular stent was used in 17 patients. Coronary flow velocity within the stent was also recorded during a slow pullback. RESULTS: Following placement of the stents, the percentage diameter stenosis was similar for both the tubular and coil stents (mean (SE) 11 (2)% v 13 (2)%, NS). However, distal CFVR was higher after stenting with a tubular stent compared with a coil stent (2.46 (0.13) v 1.96 (0.14), p < 0.05). Furthermore, pullback through the stent detected a major flow velocity increase within coil stents but not in tubular stents (83 (24)% v 5 (5)%, p < 0.05). CONCLUSIONS: In spite of similar angiographic improvement, placement of coil stents was associated with inferior functional results compared with tubular stents. The flow velocity acceleration within the coil stents suggests the presence of a residual narrowing within the stent, which is not appreciated on angiography.

Analysis of Variance↗
PubMed1998

User-friendly and low-cost computer system for immediate review, analysis, and reconstruction of intracoronary ultrasound images.

Rapid review, digital recording, on-line quantification, and three-dimensional reconstruction are all essential in the evaluation of intracoronary ultrasound images during coronary interventions. We describe a low-cost method that offers all these necessary features. The proposed method uses the QuickTime compatible video digitizers of standard multimedia Apple Macintosh or PowerPC desktop computers and the freeware software Object Image 1.60.

Computer Systems↗
PubMed1996

Coronary flow reserve during coronary angioplasty in patients with a recent myocardial infarction: relation to stenosis and myocardial viability.

OBJECTIVES: In the present study, we examined post-stenotic coronary flow before and after percutaneous transluminal coronary angioplasty (PTCA) in patients with and without a recent myocardial infarction (MI) and related it to stenosis severity and residual viability. BACKGROUND: Post-stenotic coronary blood flow velocity reserve (CFVR) has been used with success to estimate functional stenosis severity in patients with stable angina. However, in patients with a recent MI, the impaired coronary vasodilator response of the reperfused myocardium may substantially alter the flow dynamics of the infarct-related artery. METHODS: Distal coronary flow velocities were recorded before and after PTCA in 36 patients at day 13 +/- 7 (mean +/- SD) after acute MI and in 38 patients without MI. The CFVR was assessed by the ratio of distal hyperemic to baseline average peak velocity, using a 0.014-in. Doppler guide wire. Stenosis severity was analyzed by quantitative coronary angiography, and infarct size was assessed scintigraphically. RESULTS: For similar angiographic stenosis severity, pre- and post-PTCA values of CFVR were significantly lower in patients with than without MI: 1.22 +/- 0.26 versus 1.50 +/- 0.45 before PTCA (p < 0.05) and 1.72 +/- 0.43 versus 2.21 +/- 0.74 after PTCA, respectively (p < 0.01). Although CFVR increased significantly (p < 0.0001) after angiographically successful PTCA in both study groups, abnormal CFVR (< or = 2.0) was still observed in 80% of patients with MI and in 44% of those without MI (MI vs. no MI, p = 0.001). Patients with an extensive infarction (relative infarct size > or = 50%) and those with a small infarction (relative infarct size < 50%) had comparable levels of post-PTCA CFVR (1.6 +/- 0.3 vs. 1.8 +/- 0.5, p = NS). Among a variety of factors, angiographic stenosis severity was the most important determinant of CFVR in both study groups. CONCLUSIONS: In patients with a recent MI, CFVR was significantly lower than in those without MI, both before and after PTCA. Besides the presence of this postreperfusion-related impairment of the coronary vasodilating response, CFVR was mainly influenced by stenosis severity and not by residual viability.

Adult↗
PubMed1996

Acute Luminal Gain after Stenting: Comparison of Gianturco-Roubin and Palmaz-Schatz Stents.

The Gianturco-Roubin stent has an open coil structure with a clamshell configuration and a relatively large distance between its transversely parallel struts. This stent design results in a low metallic surface area but may possibly also lead to more vessel recoil and less acute luminal gain than that obtained with the more rigid Palmaz-Schatz stent. The present study compares the acute angiographic results obtained with both stents. Quantitative coronary arteriography was performed in 77 patients in whom one of the following was successfully implanted: 1) a Palmaz-Schatz stent (n = 27), 2) a normally sized (n = 25) Gianturco-Roubin stent (n = 25), 3) a one-size oversized Gianturco-Roubin stent (n = 30). Diameter stenosis after stenting was greater in the patients with a normally sized Gianturco-Roubin stent (28 +/- 2%) than in those with a Palmaz-Schatz stent (18 +/- 1.2%, p < 0.05). This difference was in part attributed to a more important acute luminal loss due to elastic recoil and plaque protrusion with Gianturco-Roubin stents (25 +/- 2%) compared with Palmaz-Schatz stents (11 +/- 1.5%, p < 0.0001). However, in the patients with an oversized Gianturco-Roubin stent acute gain was similar to that obtained with Palmaz-Schatz stents (50 +/- 3.2% vs. 48 +/- 3%, p=0.68) and residual stenosis (20 +/- 2%) was less than that with a normally sized Gianturco-Roubin stent (p < 0.05). In the patients with an oversized Gianturco-Roubin stent the actual size during deployment (109 +/- 2.9% of the reference diameter) was smaller than the nominal size (122 +/- 1.7%). Thus, one-size oversizing of the Gianturco-Roubin stent corrects for the smaller actual than nominal diameter of this stent. It also compensates for the greater recoil observed with this stent and leads to similar acute diameter gain as that obtained with a Palmaz-Schatz stent without causing an excessive coronary artery stretching.

Journal Article↗
PubMed1996

Clinical outcome of patients with an uncomplicated myocardial infarction: effect of revascularization.

In 80 patients (pts) with an uncomplicated myocardial infarction (MI) the rate of major cardiac events (MACE) including cardiac death, non-fatal myocardial infarction and recurrent ischemia requiring hospitalization was prospectively assessed over a mean follow-up period of 17 +/- 9 months and related to clinical, angiographic and scintigraphic findings, the latter obtained from adenosine Tc-99m sestamibi SPECT imaging. Decision for revascularization was mainly based on angiographic data and was carried out in a total of 50 patients (angioplasty in 34 pts and cardiac surgery in 16 pts). The overall MACE rate was 24% with a mortality and myocardial infarction rate of 4% and 5%, respectively. Early (< 2 months) revascularization seemed to have a beneficial effect on clinical outcome as was suggested by the following findings: 1) Cardiac events (MACE) were not significantly different in patients with versus without revascularization (MACE 24% versus 23%) although the former constituted a subgroup at higher risk for ischemic events because of a more extensive coronary artery disease state. 2) In the subset of patients with at least one significant coronary artery stenosis the clinical outcome was significantly better in those who were revascularized than in those who underwent no revascularization (MACE 24% vs 47%, p < 0.05. Among a variety of factors, including the scintigraphic and angiographic extent of coronary artery disease and post-MI treatment strategy, multivariate analysis selected hypercholesterolemia (> 240 mg%) as the only independent predictor of MACE with a more than fourfold increase in risk for development of MACE. These data suggest that the natural history, especially the rate of recurrent ischemic events, can be favourably changed by an elective and early revascularization, strategically oriented by the results of the angio-graphic study. Furthermore, our data emphasized the deleterious role of hypercholesterolemia on clinical outcome in patients with a recent MI.

Angioplasty, Balloon, Coronary↗
PubMed1993

Steinert's disease.

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1992

Paradoxical vasoconstriction as result of acetylcholine and serotonin in diseased human coronary arteries.

UNLABELLED: In experimental atherosclerosis, impairment of endothelium-dependent vasodilation results in an unmasking of potent vasoconstrictor responses to serotonin, a substance released by aggregating platelets. To determine whether similar changes occur in diseased human coronary arteries, the responses to selective intracoronary infusions of acetylcholine and serotonin (both endothelium-dependent vasodilators) and to isosorbide dinitrate (a dilator directly acting on the smooth muscle) were assessed by quantitative coronary arteriography in 16 patients with angiographically normal coronary arteries, in 10 patients with minimal (less than 30% narrowing) and in five patients with more advanced (greater than 50% narrowing) coronary atherosclerosis. Acetylcholine induced constriction in diseased coronary arteries, but in patients with normal coronary arteriograms, it caused dilatation in seven patients (smooth dilators) and constriction in nine patients (smooth constrictors). In the smooth dilators, however, serotonin evoked no significant changes (+1.4 +/- 4.1%), whereas in the smooth constrictors and in patients with diseased coronary arteries, serotonin caused dose-dependent constriction. The vasoconstrictor responses to serotonin were similar in patients with minimal (-26.5 +/- 4.7%) and more advanced atherosclerosis (-30.9 +/- 5.3%). In one patient with coronary artery disease, serotonin caused a temporary coronary occlusion. All other patients dilated in response to isosorbide dinitrate. The vasomotor responses to acetylcholine and to serotonin were thus shown to be completely in parallel. CONCLUSION: impairment of endothelium-dependent vasodilation unmasks potent vasoconstrictor responses to serotonin both in early and advanced coronary atherosclerosis. These changes may play an important role in the pathogenesis of a dynamic coronary artery stenosis.

Acetylcholine↗
PubMed1992

External vibration interference of activity based rate responsive pacemakers.

The change of the pacing rate in response to external vibration interference was assessed in four rate responsive pacemakers with a piezoelectric crystal (Medtronic Activitrax 8403, Siemens Sensolog 3, Biotronik Ergos 01, and Medtronic Legend 8417) and one with an accelerometer (CPI Excel VR 1119). They were tested in the laboratory. External vibration was simulated in vitro by exposing the different pacemakers to a controlled sinusoidal vibration force generated by a Millar pressure vibration amplifier type MGM-30 (Millar Instruments, Inc., Houston, TX, USA). All pacemakers were programmed at standard settings. Two types of vibration forces were applied: (1) one with varying amplitude but with constant vibration frequency; and (2) one with varying frequency but with constant vibration amplitude. In this manner curves of pacing rate versus vibration forces versus vibration frequency were obtained. High vibration forces and low vibration frequencies were associated with the highest pacing rate response. In this experimental setting, the pacemaker based on the accelerometer principle apparently was the least sensitive to high frequency vibrations, which are known to be related to environmental interference. It also seemed more appropriately responsive in the lower frequency range, which is more appropriate for the detection of true physiological activity.

Acceleration↗
PubMed1991

Intracerebral hemorrhage after lumbar myelography with iohexol: report of a case and review of the literature.

Intracranial hemorrhage is an uncommon complication of dural puncture. In most instances, hematomas are subdural; they may be unilateral or bilateral. Rarely are intraparenchymal cerebral hemorrhages related to dural puncture. This report describes a delayed occurrence of bilateral intraparenchymal hemorrhages in a 38-year-old woman 7 days after lumbar myelography with iohexol. A review of the literature is presented.

Adult↗
PubMed1988

Modification of the late asthmatic reaction by hyposensitization in asthmatic children allergic to house dust mite (Dermatophagoides pteronyssinus) or grass pollen.

The frequency and severity of the late asthmatic reaction (LAR) was studied in asthmatic children allergic to house dust mite (HDM) or grass pollen (GP) with and without hyposensitization (HS). The four groups were comparable according to their severity of asthma. All children were allergic to HDM (Dermatophagoides pteronyssinus) or GP according to history, skin testing and specific IgE determination via the RAST. The LAR occurred less frequently (29% versus 73%) (P less than 0.001) and was less severe in children receiving HS. The difference was significant between the children allergic to HDM as well as between children allergic to GP. The immediate asthmatic reaction (IAR) was also less severe in children allergic to HDM who received HS, compared to those who never received HS, (P = 0.033) although the PD20 of the HDM challenge (PD20HDM) was not different between the two groups. In children allergic to GP, there was no difference in PD20 of the GP challenge (PD20GP) or in severity of the IAR, whether the children received HS or not. There was no difference between the PD20HDM in patients who developed a LAR and in patients who did not. There was no relation between the type of asthmatic reaction following the allergen provocation test and the level of circulating immune complexes (CIC) and the level of house dust mite-specific IgG (IgGHDM) or grass pollen-specific IgE (IgGGP) in the different groups, determined before the challenge. There was a decrease in the level of IgG containing CIC (IgGCIC) during the LAR. It is concluded that the LAR occurs less frequently and is less severe in asthmatic children who receive HS.

Adolescent↗