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Biomedical subjects

V Voudris

Publications and source records attributed to V Voudris.

At least 19 recordsLinked to original sources
PubMed2006

Iloprost for prevention of contrast-mediated nephropathy in high-risk patients undergoing a coronary procedure. Results of a randomized pilot study.

OBJECTIVE: The prevention of contrast-mediated nephropathy (CMN), which accounts for considerable morbidity and mortality, remains a vexing problem. Contrast induced renal vasoconstriction is believed to play a pivotal role in the CMN mechanism. The aim of this pilot study was to examine the safety and efficacy of two doses of the prostacyclin analogue iloprost in preventing CMN in high-risk patients undergoing a coronary procedure. METHODS: Forty-five patients undergoing coronary angiography and/or intervention who had a serum creatinine concentration >or=1.4 mg/dL were randomized to receive iloprost at 1 or 2 ng/kg/min or placebo, beginning 30-90 minutes before and terminating 4 hours after the procedure. CMN was defined by an absolute increase of serum creatinine >or=0.5 mg/dL or a relative increase of >or=25% measured 2 to 5 days after the procedure. Study drug infusion was discontinued in 2 patients in the low-dose iloprost group due to flush/nausea and in 5 patients in the high-dose group due to severe hypotension. RESULTS: The mean creatinine concentration change in the placebo group (0.02 mg/dL) was unfavorable compared to that in the low-dose iloprost group (-0.11 mg/dL; p=0.08) and high-dose iloprost group (-0.23 mg/dL; p=0.048). The difference between the absolute changes in creatinine clearance was favorable compared to placebo for both the low (mean difference 6.1 mL/min, 95%CI -0.5 to 12.8 mL/min, p=0.07) and the high-dose iloprost group (11.8 mL/min, 95%CI 4.7 to 18.8 mL/min, p=0.002). Three cases of CMN were recorded; all in the placebo group (p=0.032). CONCLUSIONS: The results of this pilot study suggest that prophylactic administration of iloprost may effectively prevent CMN, but higher dosages are connected with substantial tolerability issues.

Aged↗
PubMed2004

Radiation dose measurements to the interventional cardiologist using an electronic personal dosemeter.

The aim of this study was to investigate the use of an electronic personal dosemeter (EPD) worn by a senior cardiologist in an Interventional Cardiology (IC) Laboratory of a busy cardiac centre and how the results could help in the evaluation of radiation protection equipment used. Patient samples consist of 28 patients (10 coronary angiographies (CAs) and 18 percutaneous transluminal coronary angioplasties (PTCAs)). Patient dose was measured with a dose-area product (DAP) meter. Cardiologist radiation dose value written on the EPD as well as the protective equipment used was collected. Between patient and cardiologist dose, a significant correlation was found in CA and a moderate correlation in PTCA. Mean cardiologist effective dose E per procedure was found to be 0.2 microSv in CA and 0.3 microSv in PTCA. EPD proved to be an easy, direct and straightforward way to measure the radiation dose that the cardiologist receives in an IC laboratory.

Angioplasty, Balloon, Coronary↗
PubMed2003

Coronary flow: clinical considerations.

In the measurement of coronary blood flow to determine the success of percutaneous coronary intervention, invasive techniques, coupled with plaque characterisation and other intracoronary imaging modalities, may prove invaluable.

Blood Flow Velocity↗
PubMed2003

Postprandial hypertriglyceridaemia in patients with Tangier disease.

BACKGROUND: Tangier disease (TD) is the phenotypic expression of rare familial syndromes with mutations in the ABCA1 transporter. TD results in extremely low high density lipoprotein (HDL) cholesterol and reduced low density lipoprotein cholesterol, with normal or mildly increased fasting triglyceride (TG) concentrations. Although there is a close relation between HDL cholesterol values and atherogenesis, the risk of coronary artery disease is variable in TD. Raised fasting or postprandial TG values frequently accompany low HDL cholesterol and can add to the risk of a vascular event. AIMS: To investigate the postprandial TG response in TD. PATIENTS AND METHODS: Five patients (three homozygotes (HTD) and two heterozygotes (hTD)) from one family were studied. One was defined by DNA analysis as homozygous for a new mutation (C2033A) resulting in truncation of the ABCA1 protein. Their TG concentrations were measured before and four, six, and eight hours after a standardised fat load and compared with a control group. RESULTS: Two patients with HTD had high fasting TG concentrations. The third patient with HTD, the two with hTD, and the control group had TG concentrations within the reference range. The patients with HTD had increased postprandial peak TG values when compared with those with hTD and controls. CONCLUSION: Patients with HTD, with or without fasting hypertriglyceridaemia, may have an increased TG response to a fatty meal. The small number of patients does not allow definitive conclusions to be made. However, postprandial hypertriglyceridaemia could be a reason why some patients with TD develop premature atherosclerosis.

Adult↗
PubMed2001

Randomized comparison of coronary stent implantation under ultrasound or angiographic guidance to reduce stent restenosis (OPTICUS Study).

BACKGROUND: Observational studies in selected patients have shown remarkably low restenosis rates after ultrasound-guided stent implantation. However, it is unknown whether this implantation strategy improves long-term angiographic and clinical outcome in routine clinical practice. Methods and Results-- A total of 550 patients with a symptomatic coronary lesion or silent ischemia were randomly assigned to either ultrasound-guided or angiography-guided implantation of </=2 tubular stents. The primary end points were angiographic dichotomous restenosis rate, minimal lumen diameter, and percent diameter stenosis after 6 months as determined by quantitative coronary angiography. Secondary end points were the occurrence rates of major adverse cardiac events (death, myocardial infarction, coronary bypass surgery, and repeat percutaneous intervention) after 6 and 12 months of follow-up. At 6 months, repeat angiography revealed no significant differences between the groups with ultrasound- or angiography-guided stent implantation with respect to dichotomous restenosis rate (24.5% versus 22.8%, P=0.68), minimal lumen diameter (1.95+/-0.72 mm versus 1.91+/-0.68 mm, P=0.52), and percent diameter stenosis (34.8+/-20.6% versus 36.8+/-19.6%, P=0.29), respectively. At 12 months, neither major adverse cardiac events (relative risk, 1.07; 95% CI 0.75 to 1.52; P=0.71) nor repeat percutaneous interventions (relative risk 1.04; 95% CI 0.64 to 1.67; P=0.87) were reduced in the ultrasound-guided group. CONCLUSIONS: This study does not support the routine use of ultrasound guidance for coronary stenting. Angiography-guided optimization of tubular stents can be performed with comparable angiographic and clinical long-term results.

Blood Vessel Prosthesis Implantation↗
PubMed2001

The immediate and long-term effect of optimal balloon angioplasty on the absolute coronary blood flow velocity reserve. A subanalysis of the DEBATE study. Doppler Endpoints Balloon Angioplasty Trial Europe.

BACKGROUND: There are limited data regarding the immediate and long-term effect of balloon angioplasty on the coronary flow reserve evaluated in a multicentre setting. METHODS AND RESULTS: A total of 86 patients with one-vessel disease and normal left ventricular function were analysed before and after optimal balloon angioplasty (diameter stenosis <35%) and at 6-month follow-up. Coronary flow reserve was assessed with a Doppler guide wire. A low coronary flow reserve ( 2.5 (46% vs 23% and 36% vs 16%, respectively; P<0.05) due to a trend towards restenosis (29% vs 16%; P=0.15) or a low coronary flow reserve at follow-up due to persistent elevated baseline blood flow velocity. Patients without restenosis showed a decrease or increase of coronary flow reserve during follow-up, determined by alterations of hyperaemic blood flow velocity. CONCLUSIONS: Patients with an impaired coronary flow reserve directly after optimal balloon angioplasty showed a higher target lesion revascularization rate compared to patients with a coronary flow reserve >2.5. This patient group consists of patients prone to develop restenosis, while other patients are characterized by a persistently low coronary flow reserve, probably secondary to disturbed autoregulation and/or diffuse mild coronary atherosclerosis. Coronary flow reserve alterations in patients without restenosis were related to changes in hyperaemic blood flow velocity, suggesting that this phenomenon relates to epicardial remodelling.

Adult↗
PubMed2000

Randomized comparison of primary stenting and provisional balloon angioplasty guided by flow velocity measurement. Doppler Endpoints Balloon Angioplasty Trial Europe (DEBATE) II Study Group.

BACKGROUND: Coronary stenting improves outcomes compared with balloon angioplasty, but it is costly and may have other disadvantages. Limiting stent use to patients with a suboptimal result after angioplasty (provisional angioplasty) may be as effective and less expensive. METHODS AND RESULTS: To analyze the cost-effectiveness of provisional angioplasty, patients scheduled for single-vessel angioplasty were first randomized to receive primary stenting (97 patients) or balloon angioplasty guided by Doppler flow velocity and angiography (523 patients). Patients in the latter group were further randomized after optimization to either additional stenting or termination of the procedure to further investigate what is "optimal." An optimal result was defined as a flow reserve >2.5 and a diameter stenosis <36%. Bailout stenting was needed in 129 patients (25%) who were randomized to balloon angioplasty, and an optimal result was obtained in 184 of the 523 patients (35%). There was no significant difference in event-free survival at 1 year between primary stenting (86.6%) and provisional angioplasty (85.6%). Costs after 1 year were significantly higher for provisional angioplasty (EUR 6573 versus EUR 5885; P:=0.014). Results after the second randomization showed that stenting was also more effective after optimal balloon angioplasty (1-year event free survival, 93.5% versus 84.1%; P:=0. 066). CONCLUSIONS: After 1 year of follow-up, provisional angioplasty was more expensive and without clinical benefit. The beneficial value of stenting is not limited to patients with a suboptimal result after balloon angioplasty.

Analysis of Variance↗
PubMed2000

Prediction of restenosis after coronary angioplasty by use of a new index: TIMI frame count/minimal luminal diameter ratio.

BACKGROUND: It has been shown recently that postangioplasty coronary flow reserve and the degree of residual stenosis have a modest predictive value for short- and long-term clinical outcomes after coronary angioplasty. Corrected TIMI frame count (CTFC) is a simple quantitative index of coronary blood flow. Its relationship with Doppler coronary flow velocity and clinical outcome after coronary angioplasty has not been fully clarified. The aim of this study was to identify clinical, angiographic, and functional predictors of clinical and angiographic restenosis after conventional coronary angioplasty. METHODS AND RESULTS: We studied 70 consecutive patients in whom intracoronary Doppler flow-velocity measurements were performed before and after angioplasty. Patients were evaluated for restenosis by clinical follow-up, exercise stress test/(201)Tl scintigraphy, and follow-up angiography, which was performed at 10. 5+/-10.3 months in 63 patients. According to the results of univariate analysis, a new index, postangioplasty CTFC/minimal luminal diameter (MLD) ratio, was created. Multivariate analysis revealed that CTFC/MLD ratio was the only independent predictor of angiographic (OR 2.02; 95% CI 1.37 to 2.97; P<0.0004) and clinical (OR 1.60; 95% CI 1.15 to 2.21; P<0.005) restenosis. The receiver operating characteristic curve area of this index was 79% for angiographic and 73% for clinical restenosis. The optimal CTFC/MLD ratio cutoff values were 7.88 for angiographic and 7.94 for clinical restenosis, respectively. CONCLUSIONS: Our data indicate that postangioplasty CTFC/MLD ratio, which incorporates both the angiographic and functional features of coronary lesions, is a reliable, objective, and inexpensive index for prediction of angiographic and clinical restenosis after conventional coronary angioplasty.

Aged↗
PubMed2000

Intracoronary irradiation and stent placement in a chronic total coronary occlusion: long-term clinical, angiographic, and intracoronary ultrasound follow-up.

Intracoronary irradiation emerges as a promising method in a variety of restenosis prone coronary lesions. We report the acute and long-term clinical, angiographic, and ICUS follow-up of a patient who underwent a successful angioplasty with stent placement in a chronic coronary occlusion with adjuvant gamma-intracoronary radiation.

Angioplasty, Balloon, Coronary↗
PubMed2000

Noninvasive assessment of left ventricular systolic function by stress-shortening relation, rate of change of power, preload-adjusted maximal power, and ejection force in idiopathic dilated cardiomyopathy: prognostic implications.

Indexes of left ventricular systolic function that are considered relatively load-insensitive were assessed to determine their relation to the severity of heart failure symptoms and their ability to predict the outcome of idiopathic dilated cardiomyopathy. Stress, flow, power, and ejection force were calculated throughout ejection by echocardiography at rest in 35 patients with idiopathic dilated cardiomyopathy and in 20 control subjects. Patients were evaluated prospectively every 6 months for 2 years. Asymptomatic patients were separated most clearly from New York Heart Association (NYHA) class II by end-systolic stress; NYHA class II patients were separated from NYHA class III and the latter from NYHA class IV by peak rate of change of flow. Ten patients showed improvement in symptoms as well as in systolic indexes; none of them died during the follow-up. Improvement was unpredictable with the evaluated variables. One- and 2-year cardiovascular mortality rates were 17% and 26%, respectively. Patients whose condition did not improve after the first year had a 17% second-year mortality rate. Peak rate of change of power predicted death with 100% sensitivity, 56% specificity, and 64% positive predictive value in NYHA III and IV patients.

Blood Flow Velocity↗
PubMed2000

Angiographical and Doppler flow-derived parameters for assessment of coronary lesion severity and its relation to the result of exercise electrocardiography. DEBATE study group. Doppler Endpoints Balloon Angioplasty Trial Europe.

AIMS: Evaluation of angiographical and intracoronary Doppler-derived parameters of coronary stenosis severity. METHODS AND RESULTS: A total of 225 patients with one-vessel disease were studied before PTCA and at 6 months follow-up. Exercise electrocardiography was performed to document presence (n = 157) or absence (n = 138) of an ST segment shift (> or =0.1 mV). Intracoronary blood flow velocity analysis was performed to determine the proximal/distal flow velocity ratio, the distal diastolic/systolic flow velocity ratio and coronary flow velocity reserve. Receiver operator characteristic curves were calculated to assess the predictive value of these variables compared with the exercise test. The distal coronary flow velocity reserve demonstrated the best linear correlation for both percentage diameter stenosis and minimum lumen diameter (r = 0.67 and r = 0.66; P<0.01), compared to the diastolic/systolic flow velocity ratio (r = 0.19 and r = 0.14; P<0.01) and the proximal/distal flow velocity ratio (r = 0.03 and r = 0.07; not significant). The areas under the curve were 0. 84+/-0.02; 0.82+/-0.03 and 0.83+/-0.03 for diameter stenosis, minimum lumen diameter and coronary flow velocity reserve, respectively. Logistic regression analysis revealed that the percentage diameter stenosis or minimum lumen diameter and coronary flow velocity reserve were independent predictors for the result of stress testing. CONCLUSIONS: The distal coronary flow velocity reserve is the best intracoronary Doppler parameter for evaluation of coronary narrowings. Angiographical estimates of coronary lesion severity and distal coronary flow velocity reserve are good and independent predictors for the assessment of functional severity of coronary stenosis, emphasizing the complementary role of these parameters for clinical decision making.

Adult↗
PubMed2000

Antiplatelet is superior to anticoagulant treatment after coronary stenting: fewer coronary and other events within 30 days after stenting.

Stent prosthesis is a high efficacious method with low complication rates. However, the ideal adjunctive therapy following stent implantation remains controversial. The authors compared the effectiveness and complication rates of aspirin-ticlopidine antiplatelet therapy vs. anticoagulant therapy with acenocoumarol within 30 days following stent prosthesis. They prospectively studied 404 patients following stent prosthesis while randomly receiving anticoagulant (Group A: 201 patients) vs. antiplatelet treatment (Group B: 203 patients). Groups A and B were similar in demographic data (age, gender), stent location, clinical presentation, indication of stenting, and type of implanted stent. Chi-square test, t test, and Wilcoxon test for two samples were used for statistical analysis of the results. Stent implantation was attempted in 434 cases. This was successful in 70/85 (82%) of the bailout, 122/135 (90%) of the suboptimal, and 212/214 (99%) of the elective cases. In 201 patients anticoagulant treatment with acenocoumarol was administered for 4 weeks (group A), while 203 received antiplatelet treatment with ticlopidine (group B). The need for reintervention was less and total cardiac events were fewer in group B than in group A: three (1.5%) and nine (4.4%) vs 18 (9%) and 29 (14.4%), p<0.0008 and p<0.006 respectively. Hemorrhagic complications and total noncardiac events were fewer in group B than in group A: six (3%) and six (3%) vs. 18 (9%) and 19 (9.5%), p<0.01 and p<0.007 respectively. The length of hospital stay was shorter in group B than in A, p<0.0001. In conclusion, in this study of intracoronary stenting the authors had a high success rate in 434 attempted cases. Antiplatelet therapy was accompanied by fewer cardiac and noncardiac 1 month events when compared with anticoagulant therapy, supporting its role as the adjunctive treatment of choice post-stenting for the time being.

Acenocoumarol↗
PubMed1999

Usefulness of flow reserve in the left internal mammary artery to determine graft patency to the left anterior descending coronary artery.

Two-dimensional Doppler echocardiography (DE) and intravascular Doppler-tipped guidewire (flowire) have been used to measure flow in aortocoronary conduits at rest and during hyperemia, but they have not been compared. We investigated which flow velocity parameters obtained with these 2 different techniques can predict left internal mammary artery (LIMA) graft patency. Twenty-nine patients with previous coronary artery bypass grafting referred for evaluation of symptoms of coronary artery disease were studied after cardiac catheterization using the flowire and DE. Proximal LIMA graft flow velocity was measured at rest and during hyperemia produced by 140 microg/kg/min of intravenous adenosine infusion over 6 minutes with both methods. Normal LIMA grafts and left anterior descending artery (LAD) distal to the anastomosis were present in 16 patients, whereas 13 had >70% graft or native vessel stenosis. The coronary flow velocity reserve (r = 0.79) and the diastolic-to-systolic velocity ratio during hyperemia (r = 0.73) correlated very well between the 2 techniques. Among the variables obtained with the 2 techniques, the intragraft coronary flow velocity reserve measured by both methods was the only independent predictor of graft/recipient LAD patency. This variable had a sensitivity and specificity of 86% at a cutoff point of 2.07 with the flowire method and 83% at a cutoff point of 1.54 with DE. The areas below the receiver-operating characteristic curves were 0.91 and 0.93, respectively. Coronary flow velocity reserve measurements obtained with DE appears a reliable noninvasive method for assessing LIMA graft and/or LAD distal to the anastomosis patency in patients after bypass surgery and correlate very well with those directly obtained by intravascular Doppler.

Adenosine Triphosphate↗
PubMed1998

Effect of plaque burden on coronary vasoreactivity in early atherosclerosis.

Coronary atherosclerosis, during its initial stages of development, may result in abnormal endothelium-dependent vasomotor responses. The relation between the degree of vasoreactivity and the amount of atheromatous plaque load has not been decisively determined. The aim of the present study was to investigate the effects of segmental plaque burden on endothelium-dependent and independent coronary stimulation. We studied 37 individual coronary segments along the course of coronary arteries that had angiographically either nonvisible or nonobstructive atheromatous lesions. Endothelium-dependent and independent stimulation of each segment from 10 patients with known significant coronary artery disease was examined with intracoronary administrations of normal saline, acetylcholine 10(-6) M and 10(-5) M, and nitroglycerin, respectively, using quantitative coronary angiography. Simultaneous vasomotor effects on the microcirculation were evaluated by a Doppler guidewire (Flowire). Subsequently, intracoronary ultrasound was used at each segment for detailed morphometric and composition analysis. By quantitative coronary angiography, when compared with normal saline, acetylcholine produced a reduction in minimal lumen diameter of 15.2 +/- 25.6%, and nitroglycerin produced an increase of 18.0 +/- 22.5%. The degree of vasoconstriction induced by acetylcholine correlated inversely (r = 0.51, p = 0.001) to the amount of segmental maximal plaque thickness. No relation between the response to nitroglycerin and the parameters obtained by intracoronary ultrasound was documented. Fibrous coronary plaques showed less vasomotor changes than plaques with mixed echogenicity, probably due to a significantly larger plaque burden. Acetylcholine produced overall a differential vasomotor response in the epicardial segments (vasoconstriction) compared with the microcirculation (vasodilation). These results indicate that in early atheromatous coronary lesions, the degree of endothelium-dependent vasoconstrictive response is inversely related to the amount of segmental plaque burden.

Acetylcholine↗
PubMed1998

Intravascular ultrasound-guided optimized stent deployment. Immediate and 6 months clinical and angiographic results from the Multicenter Ultrasound Stenting in Coronaries Study (MUSIC Study)

OBJECTIVES: A study was set up to validate the safety and feasibility of intravascular ultrasound-guided stenting without subsequent anticoagulation, and its impact on the 6 months restenosis rate. METHODS: The study was designed to be multicentred, prospective, and observational. RESULTS: One hundred and sixty-one patients with stable angina and a de novo coronary artery lesion were enrolled. In four patients, the implantation of a Palmaz-Schatz (with spiral bridge) stent had failed. One of these four patients died 3 days following bypass surgery. In two other patients, intravascular ultrasound assessment was not performed. One hundred and twenty-five of the remaining 155 patients (81%) were treated with aspirin (100 mg x day(-1)), because all three criteria for optimized stent expansion were met. Twenty-two of the remaining 38 patients (25%), in whom at least one criterion was not met were treated with aspirin and acenocoumarol (3 months, INR 2.5-3.5), while 16 patients only received aspirin. Stent thrombosis was documented in two patients (1.3%) for which repeat angioplasty was performed. During the hospital stay, there were no deaths or Q-wave myocardial infarctions. Five patients (3.2%) sustained a non-Q-wave myocardial infarction. During the follow-up period (198+/-38 days, complete for all patients, except one), one patient (0.6%) sustained a Q-wave myocardial infarction, one (0.6%) underwent bypass surgery, and repeat angioplasty was performed in nine patients (5.7%). In two of the nine patients, repeat angioplasty involved another lesion. Therefore, the target lesion revascularization rate during follow-up was 4.5% (seven patients). At quantitative coronary angiography, the minimal lumen diameter (mean+/-SD) increased from 1.12+/-0.34 mm before to 2.89+/-0.35 mm after stenting. Repeat angiography at 6 months was performed in 144 patients (92%). The minimal lumen diameter at follow-up was 2.12+/-0.67 mm. Restenosis (diameter stenosis of 50% or more) was documented in 12 patients or 8.3%. When the two patients with documented stent thrombosis are included, the restenosis rate amounts to 97%. CONCLUSIONS: These data confirm that, in selected patients, stents can safely be implanted without the use of systemic anticoagulation, provided optimal stent expansion is achieved. The exact role of intravascular ultrasound in the achievement of these results needs to be established by appropriately designed studies. In the meantime, intravascular ultrasound coupled with the Palmaz-Schatz stent incorporating a spiral bridge, may have contributed considerably to the immediate angiographic outcome, which in turn may explain the favourable clinical and angiographic outcome at 6 months.

Aged↗
PubMed1998

Dissection During Restenotic Lesion Balloon Angioplasty: Comparison with Initial Angioplasty.

The aim of this study was to assess the frequency and severity of dissection during repeat angioplasty for restenosis, to correlate the occurrence of this event with the lesion characteristics and the procedure-related factors and to examine if dissection during initial angioplasty predisposes to dissection during the repeat procedure. Sixty-nine significant lesions in native coronary arteries were treated with balloon angioplasty (A«PTCA) and retreated for restenosis with balloon angioplasty (B«PTCA). Dissection was detected less frequently during B«PTCA (7/69 vs. 18/69, p < 0.05). Anatomic variables did not differ significantly between A« and B«PTCA. Balloon to artery ratio (B/A ratio) was slightly but significantly higher during B«PTCA (1.03 +/- 0.13 vs. 0.97 +/- 0.14, p < 0.05) and duration of inflation was shorter (377 +/- 218 vs. 473 +/- 305 sec, p < 0.05). In 17 out of the 18 lesions which were dissected during A«PTCA, dissection did not occur during B«PTCA, despite the application of a higher B/A ratio (1.05 +/- 0.13 vs. 0.97 +/- 0.17, p < 0.05). Duration of inflation was shorter during B«PTCA (390 +/- 227 vs. 639 +/- 394 sec, p < 0.05). Six out of seven lesions which were dissected during B«PTCA had not been dissected during A«PTCA. In this subgroup, lesion characteristics did not differ between the two interventions and duration of inflation was shorter during B«PTCA (340 +/- 101 vs. 458 +/- 128, p < 0.05). CONCLUSIONS: Dissection occurred less frequently during restenotic lesion PTCA. Dissection during A«PTCA did not predispose to dissection during B«PTCA. These findings may be ascribed to the proliferative nature of the restenotic process.

Journal Article↗