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Biomedical subjects

V A Umans

Publications and source records attributed to V A Umans.

At least 19 recordsLinked to original sources
PubMed2001

Costs and effects of combining stenting and abciximab (ReoPro) in daily practice.

AIM: The combined use of stents and abciximab in percutaneous coronary intervention has been evaluated in the EPISTENT trial. However, the clinical and economic findings in trials are not necessarily generalisable to a general population setting. We conducted a study in daily clinical practice comparing stented and non-stented patients undergoing coronary angioplasty with abciximab administration. Furthermore, we compare our results with the findings of the EPISTENT trial. METHODS: From 1995 to 1999, refractory unstable patients scheduled for angioplasty and receiving abciximab in a Dutch regional hospital were followed prospectively for 6 months. Total costs were considered in addition to 2 composite clinical endpoints: (1) death or myocardial infarction (MI); and (2) death, MI, or any revascularisation procedure (major adverse cardiac events, MACE). RESULTS: Stented patients (N=101) experienced less MACE than non-stented patients (N=83) (6.9% vs. 16.9%, OR=0.37, P=0.04). The total costs were similar for stented and non-stented patients (EUR 7 844 vs. EUR 7 904, P=0.93). Adjustment for baseline characteristics yielded similar results, although significance subsided. The relative risk reduction of 44% that we found, closely resembles the 42% that was found in the EPISTENT trial. CONCLUSIONS: In everyday practice, as in the EPISTENT trial, the addition of a stent to abciximab treatment does seem to reduce the risk of MACE by about 40% at no additional costs.

Abciximab↗
PubMed2001

Impaired glucose metabolism predicts mortality after a myocardial infarction.

Diabetes is a risk factor for increased mortality after a myocardial infarction. Whether this applies for patients with hyperglycemia during the acute phase of a acute myocardial infarction is unclear. Therefore we determined the relation between admission plasma glucose level and mortality in a prospectively collected series of 336 consecutive AMI patients. Patients were divided in four groups based on WHO criteria for glucose levels: I: <5.6 mmol/l, II: 5.6--8.3 mmol/l, III: 8.4--11.0 mmol/l, IV: 11.1 mmol/l. The average age was 68+/-11 years with a peak CK of 1378+/-160 U/l, 34% were anterior wall AMIs and 52% were treated with thrombolysis. All patients had a long-term follow-up control at an average of 14.2 months. One year mortality rate was 19.3% and rose to 44% in patients with glucose levels >11.1 mmol/l. The mortality was higher in diabetic patients than in non-diabetic patients (40 vs. 16%; P<0.05). Multivariate analysis revealed an independent effect of glucose level on mortality. In conclusions, our study in an unselected patient population demonstrates that admission plasma glucose level independently predicts 1 year mortality even in absence of diagnosed diabetes mellitus. Further studies evaluating the effect of acute insulin intervention in reducing mortality are warranted.

Aged↗
PubMed2001

Recurrent ischaemia during continuous multilead ST-segment monitoring identifies patients with acute coronary syndromes at high risk of adverse cardiac events; meta-analysis of three studies involving 995 patients.

AIMS: Recurrent ischaemia, detected by continuous ECG monitoring, in patients with unstable angina increases the risk of unfavourable outcome. Studies that evaluated this relationship have been limited by the small series of patients. By combining data from three studies, the present analysis aims to provide an accurate assessment of the impact of recurrent ischaemia detected by multilead ECG-ischaemia monitoring on the occurrence of death and myocardial infarction in patients with acute coronary syndromes. METHODS AND RESULTS: Data were obtained from CAPTURE, PURSUIT and FROST, three trials evaluating glycoprotein IIb/IIIa blockers in patients with non-ST-elevation acute coronary syndromes. Patients were monitored for 24 h after enrollment with a computer-assisted 12-lead or a vectorcardiographic ECG-ischaemia monitoring device. In a retrospective blinded analysis, recurrent ischaemic episodes were identified by a computer algorithm. The number of ischaemic episodes was normalized to 24 h. Ischaemic episodes were detected in 271 (27%) of 995 patients. There was a direct proportional relationship between the number of ischaemic episodes per 24 h and the probability of cardiac events at 5 and 30 days. The 30-day composite of death and myocardial infarction occurred in 5.7% of patients without episodes and increased to 19.7% in patients with >/=5 episodes. After adjustment for baseline predictors of adverse outcome, the relative risk of death or myocardial infarction at 5 and 30 days increased by 25% for each additional ischaemic episode per 24 h. CONCLUSIONS: This analysis emphasizes the need for integration of multilead ECG-ischaemia monitoring systems in coronary care units and emergency wards to improve early risk stratification in patients with acute coronary syndromes.

Acute Disease↗
PubMed1999

Anticoagulant properties, clinical efficacy and safety of efegatran, a direct thrombin inhibitor, in patients with unstable angina.

AIMS: Thrombin plays a key role in the clinical syndrome of unstable angina. We investigated the safety and efficacy of five dose levels of efegatran sulphate, a direct thrombin inhibitor, compared to heparin in patients with unstable angina. METHODS: Four hundred and thirty-two patients with unstable angina were enrolled. Five dose levels of efegatran were studied sequentially, ranging from 0.105 mg. kg(-1). h(-1)to 1.2 mg. kg(-1). h(-1)over 48 h. Safety was assessed clinically, with reference to bleeding and by measuring clinical laboratory parameters. Efficacy was assessed by the number of patients experiencing any episode of recurrent ischaemia as measured by computer-assisted continuous ECG ischaemia monitoring. Clinical end-points were: episodes of recurrent angina, myocardial infarction, coronary intervention (PTCA or CABG), and death. RESULTS: Efegatran demonstrated dose dependent ex-vivo anticoagulant activity with the highest dose level of 1.2 mg. kg(-1). h(-1)resulting in steady state mean activated partial thromboplastin time values of approximately three times baseline. Thrombin time was also increased. Neither of the efegatran doses studied were able to suppress myocardial ischaemia during continuous ECG ischaemia monitoring to a greater extent than that seen with heparin. There were no statistically significant differences in clinical outcome or major bleeding between the efegatran and heparin groups. Minor bleeding and thrombophlebitis occurred more frequently in the efegatran treated patients. CONCLUSION: Administration of efegatran sulphate at levels of at least 0.63 mg. kg(-1). h(-1)provided an anti-thrombotic effect which is at least comparable to an activated partial thromboplastin time adjusted heparin infusion. There was no excess of major bleeding. The level of thrombin inhibition by efegatran, as measured by activated partial thromboplastin time, appeared to be more stable than with heparin. Thus, like other thrombin inhibitors, efegatran sulphate is easier to administer than heparin. However, no clinical benefits of efegatran over heparin were apparent.

Adult↗
PubMed1997

Comparison of usefulness of computer assisted continuous 48-h 3-lead with 12-lead ECG ischaemia monitoring for detection and quantitation of ischaemia in patients with unstable angina.

AIMS: The selection of ECG leads used for ST monitoring may influence detection and quantitation of ischaemia. METHODS: We compared on-line continuous 48-h 12-lead against 3-lead ST monitoring in 130 unstable angina patients (Mortara. ELI-100). Onset and offset of ST episodes were defined by the lead with the first > or = 100 microV ST change relative to baseline and the lead with the latest return to baseline ST level, respectively. ST episodes were calculated for 12 leads and 3 leads (V2, V5, III) separately. RESULTS: ST episodes were detected in 88 patients (77%) by 12-lead and in 71 patients (62%) by 3-lead ST monitoring (P < 0.02). The median number (25.75%) of episodes/patient was 1 (0.3) for 3-lead and 2 (1.6) for 12-lead (P < 0.0001). The total duration of ischaemia detected during 12-lead far exceeded 3-lead monitoring: 12.3 (1, 58.2) and 1.7 (0, 23.3) min respectively (P < 0.0001). The probability of recurrent ischaemia declined most during the first 24 h of monitoring. After a period without ST changes of 1, 12, 24 and 36 h, the probabilities of recurrent ischaemia were 63, 31, 14 and 9%, respectively. CONCLUSIONS: Continuous 12-lead ST monitoring increases detection rate and duration of ST episodes compared to 3-lead ST monitoring. The use of continuous 12-lead ECG monitoring devices on emergency wards and coronary care units is recommended.

Angina, Unstable↗
PubMed1996

Inter- and intra-observer variability in the qualitative categorization of coronary angiograms.

The ABC classification of the American College of Cardiology and the American Heart Association is a commonly used categorization to estimate the risk and success of intracoronary intervention, as well as the probability of restenosis. To evaluate the reliability of qualitative angiogram readings, we randomly selected 200 films from single lesion angioplasty procedures. A repeated visual assessment (> or = 2 months interval) by two independent observers resulted in kappa values of inter and intra-observer variability for the ABC lesion classification and for all separate items that compile it. Variability in assessment is expressed in percentage of total agreement, and in kappa value, which is a parameter of the agreement between two or more observations in excess of the chance agreement. Percentage of total agreement and kappa value was 67.8% and 0.33 respectively for the ABC classification, indicating a poor agreement. Probably this is due to the deficiency of strict definitions. Further investigation has to demonstrate whether improvement can be achieved using complete and detailed definitions without ambiguity, and consensus after panel assessment.

Coronary Angiography↗
PubMed1996

Clinical and angiographic comparison of matched patients with successful directional coronary atherectomy or stent implantation for primary coronary artery lesions.

OBJECTIVES: This study was designed to compare the long-term clinical and angiographic effects of successful directional atherectomy and stent implantation and to examine whether restenosis is related to the mechanism of lumen improvement as well as the extent of lumen gain. BACKGROUND: Directional atherectomy and coronary stent implantation have been shown to achieve a more optimal immediate result that may lead to a more favorable long-term angiographic outcome and fewer target vessel revascularizations than does angioplasty. However, it remains to be determined whether one of the devices used in these interventions provides consistently better results than the other. METHODS: To allow meaningful comparisons a prospectively collected series of 117 patients successfully treated with atherectomy were individually matched with a prospectively collected series of 117 patients successfully treated with stent implantation. Matching for baseline characteristics identified patients with identical lesion location and lesion severity, and immediate and late angiographic and clinical outcome were compared. To evaluate the possibility of a procedure effect on restenosis, patients were further matched for both immediate angiographic outcome and baseline characteristics, providing 150 matched patients for comparison. As confirmatory analysis, multivariate models were constructed to predict late lumen diameter. RESULTS: Matching resulted in two comparable groups with equivalent baseline clinical and stenosis characteristics (n = 117 pairs). Atherectomy led to a smaller immediate gain than stenting and, because late loss was similar in both groups, stenting resulted in a larger late lumen (1.96 +/- 0.51 vs. 1.66 +/- 0.55 mm, p < 0.0001). When patients were matched for immediate gain and baseline characteristics (n = 75 pairs), lumen loss was more pronounced after atherectomy, and thus the minimal lumen diameter at follow-up differed significantly between the two groups (1.66 +/- 0.53 vs. 1.90 +/- 0.47 mm, p = 0.004). This beneficial angiographic effect of stenting was accompanied by a reduced need for repeat interventions. Multivariate analysis confirmed the independent effect of the interventional device used, whereby less loss and greater lumen diameter at follow-up were predicted for stent implantation than for atherectomy. CONCLUSIONS: Successful stent implantation provided a more favorable long-term angiographic outcome and lower rates of restenosis and need for target lesion revascularization than did atherectomy. This favorable effect of stenting not only is related to a larger, immediate gain, but also seems to attenuate late lumen loss.

Angioplasty, Balloon, Coronary↗
PubMed1995

A comparison of hirudin with heparin in the prevention of restenosis after coronary angioplasty. Helvetica Investigators.

BACKGROUND: The likelihood of restenosis is a major limitation of coronary angioplasty. We studied whether hirudin, a highly selective inhibitor of thrombin with irreversible effects, would prevent restenosis after angioplasty. We compared two regimens of recombinant hirudin with heparin. METHODS: We randomly assigned 1141 patients with unstable angina who were scheduled for angioplasty to receive one of three treatments: (1) a bolus dose of 10,000 IU of heparin followed by an intravenous infusion of heparin for 24 hours and subcutaneous placebo twice daily for three days (382 patients), (2) a bolus dose of 40 mg of hirudin followed by an intravenous infusion of hirudin for 24 hours and subcutaneous placebo twice daily for three days (381 patients), or (3) the same hirudin regimen except that 40 mg of hirudin was given subcutaneously instead of placebo twice daily for three days (378 patients). The primary end point was event-free survival at seven months. Other end points were early cardiac events (within 96 hours), bleeding and other complications of the study treatment, and angiographic measurements of coronary diameter at six months of follow-up. RESULTS: At seven months, event-free survival was 67.3 percent in the group receiving heparin, 63.5 percent in the group receiving intravenous hirudin, and 68.0 percent in the group receiving both intravenous and subcutaneous hirudin (P = 0.61). However, the administration of hirudin was associated with a significant reduction in early cardiac events, which occurred in 11.0, 7.9, and 5.6 percent of patients in the respective groups (combined relative risk with hirudin, 0.61; 95 percent confidence interval, 0.41 to 0.90; P = 0.023). The mean minimal luminal diameters in the respective groups on follow-up angiography at six months were 1.54, 1.47, and 1.56 mm (P = 0.08). CONCLUSIONS: Although significantly fewer early cardiac events occurred with hirudin than with heparin, hirudin had no apparent benefit with longer-term follow-up.

Angina, Unstable↗
PubMed1995

Mechanism of high-speed rotational atherectomy and adjunctive balloon angioplasty revisited by quantitative coronary angiography: edge detection versus videodensitometry.

High-speed rotational coronary atherectomy (RA) is primarily used to treat complex lesions. Quantitative angiographic analysis of such complex lesions by edge detection is often unsuitable, whereas videodensitometry, measuring vessel dimensions independently of the target stenosis contours, may offer potential advantages. To gain insight into the operative mechanism of RA and to study the agreement between the two quantitative angiographic methods in measuring the minimal luminal cross-sectional area, the edge detection and videodensitometry techniques were applied to coronary angiograms of 21 lesions in 19 patients with symptoms who underwent successful RA and balloon angioplasty (BA). Obstruction diameter as determined by edge detection increased from 1.00 +/- 0.31 mm before intervention to 1.35 +/- 0.29 mm after RA (p < 0.001) and further increased to 1.74 +/- 0.33 mm after adjunctive BA (p > 0.001). The mean between-method difference (edge detection minus videodensitometry) was 0.34 mm2 before intervention, 0.13 mm2 after RA, and 0.09 mm2 after adjunctive BA (not significant). The standard deviation of the differences decreased from +/- 0.87 mm2 before intervention to +/- 0.80 mm2 after RA (not significant) and increased after BA significantly to +/- 1.21 mm2 (p < 0.05). Thus edge detection and videodensitometry provided equivalent immediate angiographic results after RA and adjunctive BA. The good agreement after RA may reflect the operative mechanism of RA, which by ablation of noncompliant plaque material yields a circular symmetric lumen with smooth surface. The increased dispersion of the between-method differences observed after adjunctive BA presumably results from dissections, plaque ruptures, and loss of luminal smoothness after balloon dilatation.

Absorptiometry, Photon↗
PubMed1995

Angiographic, ultrasonic, and angioscopic assessment of the coronary artery wall and lumen area configuration after directional atherectomy: the mechanism revisited.

The purpose of the present study was to use the complementary information of angiography, intravascular ultrasound, and intracoronary angioscopy before and after directional atherectomy to characterize the postatherectomy appearance of vessel wall contours and the mechanism of lumen enlargement. Directional coronary atherectomy aims at debulking rather than dilating a coronary artery lesion. The selective removal of the plaque may potentially minimize the vessel wall damage and lead to subsequent better late outcome. Whether plaque removal is the main mechanism of action has only to be assessed indirectly by angiography and warrants further investigation with detailed analysis of luminal changes and vessel wall damage by ultrasound and direct visualization with angioscopy. Twenty-six patients have been investigated by quantitative angiography, intravascular ultrasound, and intracoronary angioscopy (n = 19) before and after atherectomy. In addition, all retrieved specimens were microscopically examined. Ultrasound imaging showed an increase in lumen area from 1.95 +/- 0.70 mm2 to 7.86 +/- 2.16 mm2 at atherectomy. The achieved gain mainly resulted from plaque removal because plaque plus media area decreased from 18.16 +/- 4.47 mm2 to 13.13 +/- 3.10 mm2. Vessel wall stretching (i.e., change in external elastic lamina area) accounted for only 15% of lumen area gain. Luminal gain was higher in noncalcified (6.52 +/- 2.12 mm2) lesions than in lesions containing deeply located calcium (5.19 +/- 0.99 mm2) and lowest in superficially calcified lesions (5.41 +/- 2.41 mm2). Ultrasound imaging identified an atherectomy byte in 85% of the cases, whereas angioscopy revealed such a crevice in 74%. The complementary use of the three techniques revealed an underestimation of the presence of dissection/tear and new thrombus by angiography (10% and 4%) and ultrasound imaging (12% and 0%) compared with angioscopy (26% and 21%). The combined use of angiography, ultrasound, and angioscopy reveals that the postatherectomy luminal lining is not as regular and smooth as that seen by angiography. Luminal enlargement with atherectomy is achieved by plaque excision rather than arterial expansion.

Aged↗
PubMed1995

Immediate and late outcome of excimer laser and balloon coronary angioplasty: a quantitative angiographic comparison based on matched lesions.

OBJECTIVES: This study sought to compare acute lumen changes and late lumen narrowing during and after excimer laser-assisted balloon angioplasty, measured by quantitative coronary angiography, with the immediate and long-term outcome of balloon angioplasty alone. BACKGROUND: Although excimer laser coronary angioplasty is used as an adjunct or alternative to balloon angioplasty, limited comparative data exist regarding the immediate and long-term efficacy of excimer laser-assisted balloon angioplasty versus balloon angioplasty alone. METHODS: A series of 53 lesions in 47 consecutive patients successfully treated with excimer laser-assisted balloon angioplasty were individually matched after completion of 6-month follow-up angiography with 53 successfully treated balloon angioplasty lesions according to vessel location, preprocedural minimal lumen diameter and reference diameter. Immediate and long-term angiographic results were assessed by an automated lumen contour detection algorithm. RESULTS: Before intervention in the laser and balloon angioplasty groups, respectively, minimal lumen diameter (mean +/- SD) was 0.73 +/- 0.47 and 0.74 +/- 0.46 mm, and reference diameter was 2.71 +/- 0.42 and 2.72 +/- 0.41 mm. Laser angioplasty was followed by adjunctive balloon dilation in 50 lesions. Mean balloon diameter at maximal inflation was similar in both treatment groups (2.61 +/- 0.32 and 2.65 +/- 0.38 mm, respectively), resulting in similar minimal lumen diameters after intervention of 1.77 +/- 0.41 and 1.78 +/- 0.34 mm, respectively. At follow-up angiography, minimal lumen diameter after excimer laser-assisted balloon angioplasty was 1.17 +/- 0.63 mm, and that after balloon angioplasty alone was 1.46 +/- 0.67 mm (p = 0.02). The angiographic restenosis rates at follow-up using the 50% diameter stenosis cutoff criterion were 57% and 34%, respectively (p = 0.02). CONCLUSIONS: Quantitative angiographic analysis of a matched group of 106 successfully treated coronary lesions showed a similar immediate outcome but reduced long-term efficacy of excimer laser-assisted balloon angioplasty compared with that after balloon angioplasty alone.

Algorithms↗
PubMed1995

Evaluation of recombinant hirudin (CGP 39,393/TMREVASC) in the prevention of restenosis after percutaneous transluminal coronary angioplasty. Rationale and design of the HELVETICA trial, a multicentre randomized double blind heparin controlled study.

One of the main areas of interest in interventional cardiology is the understanding, and ultimate prevention of restenosis after an initially successful percutaneous transluminal coronary angioplasty. Restenosis is the recurrence of luminal narrowing following angioplasty, and still frustrates the late results in the treatment of angina pectoris. Experimental, pathological and clinical studies suggest that restenosis may occur via activation of the coagulation cascade, platelet activation and thrombus formation. Thrombin itself is identified as the most potent platelet activator, and has a pivotal role in the coagulation system. Furthermore, thrombin directly mediates smooth muscle cell proliferation by stimulating thrombin receptors at the smooth muscle cell surface. Thrombus indirectly induces excessive intimal smooth muscle cell proliferation by means of released mitogens (growth factors), which may contribute to late restenosis. Therefore direct and irreversible thrombin blockade by hirudin is deemed to be effective in the prevention of restenosis following angioplasty. The HELVETICA trial is a multicentre, randomized, double-blind heparin-controlled study, designed to compare the effects of two dose regimens of recombinant-hirudin (CGP 39,393/TMRevasc) with those of heparin on event-free survival, safety, tolerability and luminal renarrowing using quantitative coronary angiography no later than 26 weeks after the coronary angioplasty procedure.

Adult↗
PubMed1995

Differences in restenosis propensity of devices for transluminal coronary intervention. A quantitative angiographic comparison of balloon angioplasty, directional atherectomy, stent implantation and excimer laser angioplasty. CARPORT, MERCATOR, MARCATOR, PARK, and BENESTENT Trial Groups.

With the increasing clinical application of new devices for percutaneous coronary revascularization, maximization of the acute angiographic result has become widely recognized as a key factor in maintained clinical and angiographic success. What is unclear, however, is whether the specific mode of action of different devices might exert an additional independent effect on late luminal renarrowing. The purpose of this study was to investigate such a difference in the degree of provocation of luminal renarrowing (or 'restenosis propensity') by different devices, among 3660 patients, who had 4342 lesions successfully treated by balloon angioplasty (n = 3797), directional coronary atherectomy (n = 200), Palmaz-Schatz stent implantation (n = 229) or excimer laser coronary angioplasty (n = 116) and who also underwent quantitative angiographic analysis pre- and post-intervention and at 6-month follow-up. To allow valid comparisons between the groups, because of significant differences in coronary vessel size (balloon angioplasty = 2.62 +/- 0.55 mm, directional coronary atherectomy = 3.28 +/- 0.62 mm, excimer laser coronary angioplasty = 2.51 +/- 0.47 mm, Palmaz-Schatz = 3.01 +/- 0.44 mm; P < 0.0001), the comparative measurements of interest selected were the 'relative loss' in luminal diameter (RLoss = loss/vessel size) to denote the restenosis process, and the 'relative lumen at follow-up' (RLfup = minimal luminal diameter at follow up/vessel size) to represent the angiographic outcome. For consistency, lesion severity pre-intervention was represented by the 'relative lumen pre' (RLpre = minimal luminal diameter pre/vessel size) and the luminal increase at intervention was measured as 'relative gain' (relative gain = gain/ vessel size). Differences in restenosis propensity between devices was evaluated by univariate and multivariate analysis. Multivariate models were constructed to determine relative loss and relative lumen at follow-up, taking account of relative lumen pre-intervention, lesion location, relative gain, vessel size and the device used. In addition, model-estimated relative loss and relative lumen at follow-up at given relative lumen pre-intervention relative gain and vessel size, were compared among the four groups. Significant differences were detected among the groups both with respect to these estimates, as well as in the degree of influence of progressively increasing relative gain, on the extent of renarrowing (relative loss) and angiographic outcome (relative lumen at follow-up), particularly at higher levels of luminal increase (relative gain). Specifically, lesions treated by balloon angioplasty or Palmaz-Schatz stent implantation (the predominantly 'dilating' interventions) were associated with more favourable angiographic profiles than directional atherectomy or excimer laser (the mainly 'debulking' interventions). Significant effects of lesion severity and location, as well as the well known influence of luminal increase on both luminal renarrowing and late angiographic outcome were also noted. These findings indicate that propensity to restenosis after apparently successful intervention is influenced not only by the degree of luminal enlargement achieved at intervention, but by the device used to achieve it. In view of the clinical implications of such findings, further evaluation in larger randomized patient populations is warranted.

Adult↗