Biomedical subjects

J Piessens

Publications and source records attributed to J Piessens.

At least 19 recordsLinked to original sources

PubMed1995

Biocompatibility of polymer-coated oversized metallic stents implanted in normal porcine coronary arteries.

Polymer coatings have been suggested to decrease the thrombogenicity of metallic intravascular stents. The purpose of the present study was to investigate the intimal response to two different polymers when used as coatings for stents implanted in normal porcine coronary arteries. Non-articulated stainless steel-slotted tube stents were coated with either a biodegradable poly(organo)phosphazene with amino-acid ester side groups or a biostable polyurethane prepared from an amphiphilic polyether, dephenylmethane-4,4'-diisocyanate and butane diol as chain extender. In order to induce vascular wall injury, the stents were deployed using an oversized balloon. At 6 weeks follow-up, the angiographic luminal diameter measured in four polyurethane-coated stents and in six bare metallic stents was similar and 20% less than immediately post-stenting. However, in four polyphosphazene-coated stents the difference was 65% (P = 0.01 when compared to bare metal). At post-mortem morphometry the degree of luminal area stenosis was also similar in polyurethane-coated and in bare metallic stents (32 +/- 7.6% vs. 39 +/- 14%, NS) but reached 81 +/- 19% in polyphosphazene-coated stents (P < 0.03 when compared to bare metal). Thus, poly(organo)phosphazene induced a more pronounced histiolymphocytic and fibromuscular reaction than amphiphilic polyurethane, which appeared to be promising as biocompatible stent coating and, consequently, as a potential carrier for vasoactive drugs.

Animals↗

PubMed1995

Long-term effects of angiopeptin treatment in coronary angioplasty. Reduction of clinical events but not angiographic restenosis. European Angiopeptin Study Group.

BACKGROUND: Angiopeptin is a cyclic octapeptide analogue of somatostatin that has been shown to limit myointimal thickening of arteries in balloon injury models and to restore the vasodilating response to acetylcholine. A randomized, double-blind placebo controlled trial was conducted to assess the effect of angiopeptin in restenosis prevention after percutaneous transluminal coronary angioplasty (PTCA). METHODS AND RESULTS: Patients received a continuous infusion of either placebo or angiopeptin subcutaneously 6 to 24 hours before PTCA and for 4 days after PTCA (3 mg per 24 hours before PTCA followed by 6 mg per 24 hours after PTCA and for the remaining period). A 1.5-mg bolus dose of placebo or angiopeptin was given at PTCA. Aspirin (acetylsalicylic acid, 150 mg/d) was administered throughout the study period. Coronary angiograms obtained before and after PTCA and at 6-month follow-up were subjected to computerized quantification. Clinical follow-up was performed after 12 months. Primary clinical end points were death, myocardial infarction, coronary artery bypass surgery, or repeat PTCA. In total, 553 patients with 742 lesions were randomized. Clinical follow-up was available for all 553 patients. Angiopeptin decreased the clinical events during 12 months of follow-up from 36.4% in the placebo-treated group to 28.4% in the angiopeptin-treated patients (P = .046). Quantitative angiography after PTCA and at follow-up was available in 423 of 455 patients who underwent successful PTCA. The minimal lumen diameter at follow-up was 1.52 +/- 0.64 mm in the angiopeptin-treated group compared with 1.52 +/- 0.64 mm in the placebo-treated patients (P = .96). The late losses were 0.31 +/- 0.59 and 0.30 +/- 0.62 mm (P = .81) and the restenosis rates (> 50% diameter stenosis at follow-up) were 36% and 37% (P = .85) in the angiopeptin- and placebo-treated groups, respectively. CONCLUSIONS: In this study, angiopeptin significantly decreased the incidence of clinical events, principally the rate of revascularization procedures. In contrast, no significant effect was seen on angiographic variables.

Aged↗

PubMed1995

In vivo comparison of different quantitative edge detection systems used for measuring coronary arterial diameters.

Three different systems for quantitative coronary analysis [Cardiovascular Measurement System (CMS); Polytron 1000; Angiographic Workstation (AWOS)] were compared in 109 patients before and after coronary angioplasty and at follow-up coronary angiography. Correlation coefficients were low and 95% limits of agreement were wide. In general, CMS exhibited a tendency to yield lower values for very small diameters and higher values for larger vessels. The acute gain in minimal luminal diameter was considerably smaller when assessed by AWOS as compared to Polytron (0.52 vs. 0.71 mm, P < .0001) and to CMS (0.52 vs. 0.75 mm, P < .0001). Long-term gain was much larger when assessed by Polytron as compared to AWOS (18.8 vs. 11.5%, P < .001) and it was almost double for CMS as compared to AWOS (20.7 vs. 11.5%, P < .0001). In conclusion, in the individual patient very different results can be obtained when different QCA systems are used, and systematic differences between the systems are encountered.

Algorithms↗

PubMed1995

Limited value of exercise testing in the detection of silent restenosis after successful coronary angioplasty.

We studied the diagnostic value of exercise electrocardiographic (ECG) testing in 191 patients who were completely asymptomatic 6 months after a successful percutaneous transluminal coronary angioplasty procedure. With > 70%- and > 50%-diameter stenosis at follow-up as restenosis criteria, the sensitivities of exercise ECG testing were 29% and 21%; the specificities 89% and 91%; the positive predictive values 20% and 52%; the negative predictive values 93% and 70%; the accuracies 83% and 68%; and the risk ratios 2.8 and 1.7, for prevalences of 9% and 33%, respectively. There were no significant differences in the diagnostic value of exercise ECG testing between men and women, patients receiving or not receiving beta-blocking agents, and the presence or absence of pathologic Q waves. Significant differences in systolic blood pressure and the rate-pressure product at peak exercise were found between patients with and without restenosis. For individual patients, however, no practical conclusions can be drawn from these values. In conclusion, the diagnostic value of exercise ECG testing for silent restenosis is low, and supplementation with other techniques seems to be warranted.

Adult↗

PubMed1994

Usefulness of the Wiktor stent for treatment of threatened or acute closure complicating coronary angioplasty. The European Wiktor Stent Study Group.

The purpose of this study was to determine the results of the first Wiktor stent implantations in bailout conditions. From December 1990 to July 1991, in a total of 10 centers, 69 patients presenting with threatened or total closure after balloon angioplasty each received the Wiktor stent in 1 coronary artery. In these 69 coronary arteries, a total of 72 stent deliveries were attempted and 69 were successful (delivery success rate 95%). Delivery failure was treated conservatively in 2 patients and surgically in 1 patient. Emergency surgery was also performed in 2 patients, who after successful stent delivery showed progressive distal extension of the dissection. In addition, 5 patients underwent elective surgery to avoid the possibility of stent thrombosis because the myocardial area at risk was considered too large. Postprocedural blood transfusion was performed in 6% of the patients, whereas stent thrombosis occurred in 10 of 59 patients (17%), resulting in 2 deaths. Finally, 65% of the patients had a successful stent implantation without major periprocedural complications. At 6-month follow-up, only 9% of the patients experienced recurrent angina, whereas a > 50% arterial diameter narrowing was observed in 27% of the patients. Thus, the radiopaque Wiktor stent can be accurately and conveniently implanted in dissected coronary arterial segments. However, as for similar bailout devices, the number of thrombotic and bleeding events remains high.

Adult↗

PubMed1994

Discrepancy between visual estimation and computer-assisted measurement of lesion severity before and after coronary angioplasty.

One hundred fourteen coronary stenoses were quantified before and after percutaneous transluminal coronary angioplasty (PTCA) using a semi-automated digital system. The values obtained were considered as standard for comparison with visual estimation by the PTCA operator as well as by independent consensus-reading. The measured percent stenosis was 62.7 +/- 13.7% before and 27.7 +/- 12.4% after angioplasty. Before PTCA, the operator consistently overestimated stenosis severity (87.8 +/- 8.5%, P < 0.0001) and consensus-reading reduced but did not eliminate this overestimation (78.0 +/- 12.3%, P < 0.05). The error in visual estimation was inversely correlated with the measured degree of stenosis: coefficients were -0.79 (P < 0.0001) and -0.51 (P < 0.0001) for operator and consensus-readers, respectively. After PTCA, the operator underestimated the residual stenosis (21.2 +/- 9.9%, P < 0.0001) but there was no systematic bias by consensus-reading (29.4 +/- 12.0%, NS). Again the error in visual estimation was inversely correlated with the measured degree of residual stenosis: coefficients were -0.76 (P < 0.0001) and -0.58 (P < 0.0001) for operator and consensus-reading, respectively. In conclusion, the operator overestimates lesion severity before and underestimates moderate residual stenoses after PTCA, a problem only partially corrected by independent consensus-readers.

Angioplasty, Balloon, Coronary↗

PubMed1994

Recoil following Wiktor stent implantation for restenotic lesions of coronary arteries.

The purpose of this study was to determine acute recoil of the vessel wall immediately after Wiktor stent implantation in native coronary arteries of 77 consecutive patients and to assess whether there was compression or "late recoil" of the stent itself at long-term follow-up. Furthermore, the relationship between recoil and a number of clinical, angiographic, and procedural variables was studied in addition to the relation between acute recoil renarrowing or restenosis was assessed. All angiograms were analyzed with the Cardiovascular Angiography Analysis System using automated edge detection. Acute recoil was defined by the difference between the mean diameter of the fully expanded balloon on which the stent was mounted and the mean diameter of the stented segment. Late recoil was calculated by comparing the mean diameter of the stent itself immediately after implantation and at follow-up without opacification of the vessel. Acute recoil amounted to 0.25 +/- 0.32 mm or 8.2%. Multivariate analysis identified sex (coefficient = -0.20, p = 0.04) and stent/artery ratio (coefficient = 0.99, p = 0.0001) as the only independent predictors of acute recoil. "Late recoil" of the stent itself was not observed. The overall difference between the mean diameter of the stent itself immediately after implantation and at follow-up was -0.15 +/- 0.33 mm, suggesting an overall increase in diameter of 5.0%. There was no relation between acute recoil and late restenosis. On the contrary, there was a trend towards a greater degree of recoil in patients without restenosis. Moreover, linear regression analysis disclosed a weak but negative correlation between acute recoil and a loss in minimal luminal diameter (coefficient: -0.55, p = 0.04). The Wiktor stent effectively scaffolds the instrumented vessel. Only a minimal amount of acute recoil was noted, which did not contribute to late luminal renarrowing or restenosis. In addition, no late compression of the stent itself was observed. These data suggest that tissue ingrowth into the lumen of the stented segment is the main cause of late luminal renarrowing after stent implantation.

Aged↗

PubMed1994

Intravascular ultrasound versus angiography for measurement of luminal diameters in normal and diseased coronary arteries.

Quantitation of coronary luminal diameter with a 20 MHz mechanically rotating intravascular ultrasound (IVUS) catheter was compared with orthogonal-view cineangiography by use of a semiautomated edge-detection algorithm in 48 patients undergoing coronary angioplasty. Quantitative comparison of 196 matched segments was attempted, but in only 174 (88.8%) was a direct comparison of the two techniques possible. In angiographically normal coronary arteries (46 segments) the correlation between the values obtained by quantitative coronary angiography (QCA) and those achieved by IVUS was excellent (r = 0.92, p < 0.0001). For mild stenoses (80 segments) the correlation coefficient was only fair (r = 0.467, p < 0.001). After percutaneous transluminal coronary angioplasty the correlation coefficient between IVUS and QCA data (48 segments) was very weak (r = 0.282, p < 0.05). In conclusion, coronary IVUS is feasible and safe and even for a limited range of coronary arterial narrowing, significant correlations between IVUS and QCA measurements of minimal lumen diameter were found. They were excellent in normal coronary arteries, moderate in mildly diseased arteries, and weak after balloon angioplasty.

Angioplasty, Balloon, Coronary↗

PubMed1994

The brachial approach for intracoronary stent implantation.

Aggressive anticoagulation after intracoronary stent implantation leads to an increased incidence of femoral hematomas and vascular complications. Out of 74 Medtronic Wiktor stent implantations, six were performed via right brachial artery cut-down. All six attempts were successful without stent closure, bleeding or vascular complications. We feel that intracoronary Wiktor stent implantation via the brachial approach is feasible. The open artery repair and uninterrupted anticoagulation may be an interesting advantage.

Brachial Artery↗

PubMed1994

Angiotensin-converting enzyme inhibition with fosinopril sodium in the prevention of restenosis after coronary angioplasty.

BACKGROUND: Several angiotensin-converting enzyme inhibitors have antiproliferative effects in a rat model after carotid artery balloon injury. METHODS AND RESULTS: We conducted a randomized, double-blind, placebo-controlled trial to assess the effect of fosinopril, a novel angiotensin-converting enzyme inhibitor, in restenosis prevention after percutaneous transluminal coronary angioplasty (PTCA). Patients received fosinopril or matched placebo 10 mg at least 18 hours before PTCA, 20 mg at least 4 hours before PTCA, and 40 mg daily for 6 months. In addition, all patients received aspirin. Coronary angiograms before PTCA and immediately after PTCA as well as at 6-month follow-up were quantitatively analyzed. A total of 509 patients were recruited. The final per-protocol population consisted of 153 fosinopril-treated and 151 placebo-treated patients. Restenosis rates according to the National Heart, Lung, and Blood Institute criterion 4 (loss of > or = 50% of the initial gain [primary end point]) were 45.7% and 40.7% in the fosinopril and control groups, respectively (not significant). The respective mean differences in minimal coronary luminal diameter between post-PTCA and follow-up angiograms were -0.59 +/- 0.71 mm and -0.51 +/- 0.67 mm (not significant). Clinical events during the 6-month follow-up period, analyzed on an on-treatment basis, were ranked according to the most serious event. The respective numbers in the fosinopril and the control groups were for death, 0 and 0; myocardial infarction, 0 and 0; coronary artery bypass graft surgery, 1 and 3; repeat PTCA, 35 and 35; recurrent signs of ischemia necessitating early repeat coronary angiography and managed medically, 6 and 7; and none of the above, 111 and 106. All these differences were significant. CONCLUSIONS: Administration of fosinopril in a dose of 40 mg daily during 6 months after PTCA does not prevent restenosis and has no effect on overall clinical outcome.

Angioplasty, Balloon, Coronary↗

PubMed1994

Role of intravascular ultrasound in coronary artery disease: a new gold standard? An overview.

Although selective contrast coronary arteriography has been the gold standard approach for coronary imaging since more than 30 years, new coronary imaging techniques are currently under development. Intravascular ultrasound (IVUS) is perhaps the most promising of these additional techniques. IVUS makes use of miniaturised crystals incorporated at catheter tips and provides real time, cross-sectional and longitudinal, high resolution images of the arterial wall with three-dimensional reconstruction capabilities (Pandian, 1989; Coy et al., 1991; Liebsen & Klein, 1992). Different devices have been constructed. Actually two types are being used: mechanical (hand-rotated or motor-driven) systems and phased array systems using high-frequency (20-30 MHz) transducers (Bom et al., 1989). Coronary ultrasound imaging performed during catheterization is feasible and safe as demonstrated in several studies examining normal and pathologic coronary arteries (De Scheerder et al., in press).

Coronary Disease↗

PubMed1993

Angiographic predictors of recurrence of restenosis after Wiktor stent implantation in native coronary arteries.

Intracoronary stenting has been proposed as an adjunct to balloon angioplasty to improve the immediate and long-term results. However, late luminal narrowing has been reported following the implantation of a variety of stents. One of the studies conducted with the Wiktor stent is a prospective registry designed to evaluate the feasibility, safety and efficacy of elective stent implantation in patients with documented restenosis of a native coronary artery. To identify angiographic variables predicting recurrence of restenosis, the angiograms of the first 91 patients with successful stent implantation and without clinical evidence of (sub)acute thrombotic stent occlusion were analyzed with the Computer Assisted Angiographic Analysis System using automated edge detection. The incidence of restenosis was 44% by patient and 45% by stent according to the 0.72 mm criterion, and 30% by patient and 29% by stent according to the 50% diameter stenosis criterion. The risk for restenosis for several angiographic variables was determined using an univariate analysis and is expressed as odds ratio with corresponding confidence interval. The only statistically significant predictor of restenosis was the relative gain when it exceeded 0.48 using the 0.72 mm criterion (odds ratio 2.7, 95% confidence interval 1.1-6.4). Furthermore, the relation between the relative gain (increase in minimal luminal diameter normalized to vessel size) as angiographic index of vessel wall injury and relative loss (decrease in minimal luminal diameter normalized to vessel size) as index of neointimal thickening was analyzed using a linear regression analysis. When using the categorical approach to address restenosis, there is an increased risk for recurrent restenosis when the relative gain exceeds 0.48. The continuous approach underscores this concept by indicating a weak but positive relation between the relative gain and relative loss.

Aged↗

PubMed1993

Intra- and interobserver variability of a fast on-line quantitative coronary angiographic system.

To evaluate intra- and interobserver variability of an on-line quantitative coronary angiographic system, 2 independent observers measured 166 primary lesions excluding total occlusions before and after coronary angioplasty. Each observer repeated his measurement 3 times at 14 days interval. The average percent diameter stenosis results obtained by observer 1 and 2 were almost identical, before (62.2% +/- 12.0% and 62.6% +/- 11.4%, NS) and after (27.1% +/- 12.0% and 26.9% +/- 11.3%, NS) angioplasty. Variability was expressed as 95% limits of agreement (mean difference +/- 2 x SD). The intra-observer variability of observer 1 ranged from -6.6% to 6.6% before angioplasty and from -9.6% to 9.6% after angioplasty. The corresponding limits of observer 2 were -8.0% to 7.5% and -8.3% to 8.5%, respectively. The interobserver variability ranged from -10.4% to 9.6% before versus -12.5% to 13.1% after angioplasty. This variability was not influenced by vessel size. The widening of the limits observed after angioplasty was largely due to an increased variability in the measurements of the absolute minimal luminal diameter but not of the reference segment. We conclude that the intra- and interobserver variability of measurements obtained with an on-line quantitative angiographic system used for guiding coronary interventions is acceptable and without systematic bias in any direction for a wide range of primary coronary stenoses. However, the variability increases when images are acquired immediately after angioplasty.

Angioplasty, Balloon, Coronary↗

PubMed1993

Clinical applications of echocardiography in patients with acute myocardial infarction.

The ability of echocardiography to visualize ventricular wall motion abnormalities induced by ischaemia and infarction makes it an ideal tool in the assessment of patients with acute myocardial infarction. Echocardiographic derived measurements of infarction severity, such as the wall motion score index, correlate well with both early and late complications. Echocardiography is of considerable value in the detection of mechanical complications of myocardial infarction such as aneurysm and thrombus formation, infarction expansion, ventricular septal rupture and mitral regurgitation; Doppler echocardiography is of particular worth in the detection of the latter two complications. Serial echocardiographic imaging before and after various coronary reperfusion strategies allows useful assessment of the success of these strategies. Following a myocardial infarction, a predischarge resting or exercise 2-dimensional echocardiographic study provides valuable information regarding the likelihood of adverse cardiac events during long term follow-up.

Echocardiography↗

PubMed1993

The use of intracoronary ultrasound for quantitative assessment of coronary artery lumen diameter and for on-line evaluation of angioplasty results.

UNLABELLED: The value of intracoronary ultrasound for quantitative assessment of minimal coronary arterial diameter and for on-line evaluation of balloon angioplasty result was studied in 42 patients undergoing single vessel coronary angioplasty. Measurement of minimal luminal diameter of 75 matched coronary arterial segments showed a significant correlation between both the ultrasound and angiographic method (r: 0.759; p < 0.001). Furthermore using intravascular ultrasound it was possible to classify the obtained coronary balloon angioplasty results. A preliminary correlation between ultrasound classification and the in-hospital acute rethrombosis as well as late restenosis was attempted in individual patients. CONCLUSIONS: 1) Clinical use of coronary ultrasound is feasible and safe in selected cases. 2) A significant correlation between intracoronary ultrasound and quantitative coronary angiography is demonstrated. 3) Using intracoronary ultrasound seems promising for evaluation of the postangioplasty result, and may finally lead to improved selection of the interventional strategy.

Angioplasty, Balloon, Coronary↗

PubMed1992

Immediate and follow-up results of the conservative coronary angioplasty strategy for unstable angina pectoris.

To assess the results of a conservative coronary angioplasty strategy in unstable angina pectoris, the records of 1,421 consecutive patients without previous myocardial infarction undergoing a first percutaneous transluminal coronary angioplasty (PTCA) between 1986 and 1990 were reviewed. Of these patients, 631 had unstable and 790 had stable angina pectoris. Only after an intense effort to medically control symptoms, the unstable patients underwent PTCA at an average of 15.4 days (range 1 to 76) after hospital admission. Primary clinical success was achieved in 91.7% of patients with unstable and in 94.4% of those with stable angina pectoris (p = not significant). In-hospital mortality rates were 0.3 and 0.1%, respectively (p = not significant). Nonfatal in-hospital event rates for acute myocardial infarction, cerebrovascular accident and coronary bypass surgery were only slightly higher in patients with unstable angina pectoris; however, the difference from the stable group was significant when all events were combined (9 vs 5.9%; p less than 0.04). During 6-month follow-up, no significant difference in adverse events was found between the groups. The respective rates for the unstable and stable groups were 0.4 and 0.2% for death, 5.5 and 5.1% for major nonfatal events, and 17.7 and 20.1% for repeat PTCA. These results suggest that use of a conservative PTCA strategy in the treatment of patients with unstable angina pectoris results in favorable and similar immediate and 6-month outcomes compared with those in patients with stable angina pectoris.

Angina Pectoris↗

PubMed1992

Wiktor stent implantation in patients with restenosis following balloon angioplasty of a native coronary artery.

Intracoronary stenting has been introduced as an adjunct to balloon angioplasty aimed at overcoming its limitations, namely acute vessel closure and late restenosis. This study reports the first experience with the Wiktor stent implanted in the first 50 consecutive patients. All patients had restenosis of a native coronary artery lesion after prior balloon angioplasty. The target coronary artery was the left anterior descending artery in 26 patients, the circumflex artery in 7 patients and the right coronary artery in 17 patients. The implantation success rate was 98% (49 of 50 patients). There were no procedural deaths. Acute or subacute thrombotic stent occlusion occurred in 5 patients (10%). All 5 patients sustained a nonfatal acute myocardial infarction. Four of these patients underwent recanalization by means of balloon angioplasty; the remaining patient was referred for bypass surgery. A major bleeding complication occurred in 11 patients (22%): groin bleeding necessitating blood transfusion in 6, gastrointestinal bleeding in 3 and hematuria in 2. Repeat angiography was performed at a mean of 5.6 +/- 1.1 months in all but 1 patient undergoing implantation. Restenosis, defined by a reduction of greater than or equal to 0.72 mm in the minimal luminal diameter or a change in diameter stenosis from less than to greater than or equal to 50%, occurred in 20 (45%) and 13 (29%) patients, respectively. In this first experience, the easiness and high technical success rate of Wiktor stent implantation are overshadowed by a high incidence of subacute stent occlusion and bleeding complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗

PubMed1992

The conservative coronary angioplasty strategy after thrombolysis for acute myocardial infarction: immediate and short-term results.

The in-hospital and short-term follow-up results of a conservative coronary angioplasty approach in 354 consecutive patients treated after thrombolysis for acute myocardial infarction were compared with results obtained in 408 control noninfarcted patients treated for the classical indication of myocardial ischemia. Only 20% of the study patients underwent angioplasty during the initial hospitalization period and the clinical success rate was 93% versus 95% in the control group (p = NS). No significant differences in the total number of in-hospital untoward events were observed (10.2% and 7.6%, respectively). During a 7.4 +/- 1.5 month follow-up period, the total number of adverse events was only 16.9% in the study patients but it was 27.8% in the control group (p < 0.001). There were no significant differences in death, myocardial infarction, or coronary surgery as individual events, but repeat angioplasty was less frequent in the study group (14.0% versus 21.5%, p < 0.01). Thus in-hospital results in patients undergoing angioplasty on a deferred basis after thrombolysis for myocardial infarction were largely comparable with those results obtained in noninfarcted patients. Moreover, short-term clinical follow-up events were reduced when compared with the control group, an observation apparently largely related to the subgroup without clinical evidence of residual ischemia.

Aged↗