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P den Heijer

Publications and source records attributed to P den Heijer.

At least 19 recordsLinked to original sources
PubMed2001

Histopathologic validation of in-vivo angioscopic observation of coronary thrombus after angioplasty in a porcine model.

BACKGROUND: Coronary angioscopy has been reported to be superior to angiography and intravascular ultrasound for detecting intracoronary thrombus. However, in-vivo histopathologic validation of angioscopic detection of intracoronary thrombus had not been performed. OBJECTIVE: To perform histopathologic validation of in-vivo angioscopic detection of coronary thrombus. DESIGN: An experimental, blinded comparison of angioscopy and histopathology. METHODS: Coronary angioscopy was performed from 0 to 14 days after angioplasty in 39 porcine coronary arteries. When thrombus was detected by angioscopy, it was subclassified into white, mixed red-white, or red thrombus according to color. By histopathology the presence of thrombus was determined and subclassified into platelet-rich, mixed platelet-erythrocyte, or erythrocyte-rich thrombus. RESULTS: Angioscopy correctly classified 19 of 21 coronary thrombi (sensitivity 90%) but incorrectly classified nine of 18 arteries without formation of thrombus as having a thrombus (specificity 50%). Positive and negative predictive values were 68 and 82%, respectively. The angioscopic subclassification of thrombus into white, mixed red-white, or red thrombi was not correlated to the corresponding histopathologic morphology (platelet-rich, mixed platelet-erythrocyte, or erythrocyte-rich) of the observed thrombi (chi2 test: P = 0.5). CONCLUSIONS: Angioscopic detection of thrombus in vivo had high sensitivity and negative predictive value but low-to-moderate specificity and positive predictive value. Visual assessment of color of angioscopically detected thrombi seemed not to reflect histopathologic morphology of thrombus according to the definitions used in the present study.

Angioplasty, Balloon↗
PubMed2000

Hemodynamic effects of iodixanol and iohexol during ventriculography in patients with compromised left ventricular function.

A crossover study was performed to compare the hemodynamic effects of the iso-osmolar contrast agent iodixanol (Visipaque) 320 mg I/ml to those of the low-osmolar iohexol (Omnipaque) 350 mg I/ml. The main hypothesis was that iodixanol and iohexol would affect left ventricular end-diastolic pressure (LVEDP) to different degrees. In 48 patients with reduced cardiac function (mean ejection fraction 33. 4%), one ventricular injection was performed with each contrast medium. Ventricular, aortic and right atrial pressures and heart rate were measured continuously. Cardiac output (using Fick's principle) and systemic vascular resistance were calculated. LVEDP increased with both agents, but significantly less after iodixanol than after iohexol (P < 0.01), also in subgroups of patients in whom baseline LVEDP was severely increased and in whom 3-vessel disease was present. Immediate changes in variables reflecting vasodilatation were similar with both agents. In conclusion, both contrast agents influenced hemodynamics during ventriculography, but iodixanol had significantly less influence on LVEDP than did iohexol.

Adult↗
PubMed2000

Myocardial "hybrid" revascularisation with minimally invasive direct coronary artery bypass grafting combined with coronary angioplasty: preliminary results of a multicentre study.

OBJECTIVE: To expand the benefits of the minimally invasive direct coronary artery bypass (MIDCAB) concept to patients with multivessel disease, a hybrid procedure combining surgical revascularisation of the left anterior descending artery with interventional procedures for additional coronary lesions has recently been introduced. Preliminary results in patients undergoing this hybrid procedure are presented. DESIGN AND PATIENTS: Since December 1996, 35 patients (29 male, 6 female, mean (SD) age 56.7 (17) years) underwent a hybrid revascularisation performed as a primary MIDCAB procedure for grafting of the left anterior descending artery with the left internal mammary artery, followed by staged angioplasty and stenting of additional coronary lesions. RESULTS: After MIDCAB grafting the postoperative course was uneventful in all patients. Coronary reangiography after a median of seven days revealed patent and functioning left internal mammary artery grafts in all patients. Applying subsequent percutaneous transluminal coronary angioplasty and occasional stenting (n = 14), a total of 47 lesions were treated successfully. Procedure related complications did not occur. All patients remained free from angina and no stress ECG changes were recorded. CONCLUSIONS: The preliminary results of this hybrid approach to myocardial revascularisation suggest that this is a safe and effective procedure for complete revascularisation in selected patients with multivessel disease. Elderly and reoperative patients with significant comorbidity may benefit especially from such hybrid procedures by avoiding cardiopulmonary bypass and mid sternotomy.

Adult↗
PubMed1999

Coronary angioplasty induces rise in Chlamydia pneumoniae-specific antibodies.

Chlamydia pneumoniae is frequently found in atherosclerotic lesions, and high titers of specific antibodies are associated with increased risk for acute myocardial infarction. However, a causative relation has not been established yet. We performed a prospective study of 93 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) to investigate whether angioplasty influences Chlamydia-specific antibody titers and whether there is an association with restenosis. Blood samples were obtained before and 1 and 6 months after angioplasty. Antibodies against chlamydial lipopolysaccharide and against purified C. pneumoniae elementary bodies were measured by enzyme-linked immunosorbent assay (ELISA). After angioplasty, the prevalence of antibodies to lipopolysaccharide rose from 20 to 26% for immunoglobulin A (IgA), from 53 to 64% for IgG, and from 2 to 7% for IgM (P = 0.021, 0.004, and 0.046, respectively). There was a rapid increase of mean antibody titers of all antibody classes within 1 month of PTCA. During the following 5 months, antibody titers decreased slightly but were still higher than baseline values. Results of the C. pneumoniae-specific ELISA were essentially the same. The rise of anti-Chlamydia antibodies was not caused by unspecific reactivation of the immune system, as levels of antibodies against cytomegalovirus did not change. Neither seropositivity nor antibody titers were related to restenosis. However, increases in mean IgA and IgM titers were restricted to patients who had suffered from myocardial infarction earlier in their lives. In conclusion, we show that PTCA induces a stimulation of the humoral immune response against C. pneumoniae. These data support the idea that plaque disruption during angioplasty might make hidden chlamydial antigens accessible to the immune system.

Adult↗
PubMed1998

Evaluation of a weight-adjusted single-bolus plasminogen activator in patients with myocardial infarction: a double-blind, randomized angiographic trial of lanoteplase versus alteplase.

BACKGROUND: Lanoteplase (nPA) is a rationally designed variant of tissue plasminogen activator with greater fibrinolytic potency and slower plasma clearance than alteplase. METHODS AND RESULTS: InTIME (Intravenous nPA for Treatment of Infarcting Myocardium Early), a multicenter, double-blind, randomized, double-placebo angiographic trial, evaluated the dose-response relationship and safety of single-bolus, weight-adjusted lanoteplase. Patients (n=602) presenting within 6 hours of acute myocardial infarction were randomized and treated with either a single-bolus injection of lanoteplase (15, 30, 60, or 120 kU/kg) or accelerated alteplase. The primary objective was to determine TIMI grade flow at 60 minutes. Angiographic assessments were also performed at 90 minutes and on days 3 to 5. Follow-up was continued for 30 days. Lanoteplase achieved its primary objective, demonstrating a dose-response in TIMI grade 3 flow at 60 minutes (23.6% to 47.1% of subjects, P<0. 001). Similar results were observed at 90 minutes (26.1% to 57.1%, P<0.001). At 90 minutes, coronary patency (TIMI 2 or 3) increased across the dose range up to 83% of subjects at 120 kU/kg lanoteplase compared with 71.4% with alteplase. Thus, at this dose, lanoteplase was superior to alteplase in restoring coronary patency (difference, 12%; 95% CI, 1% to 23%). The early safety experience in this study suggests that lanoteplase was well tolerated at all doses with safety comparable to that of alteplase. CONCLUSIONS: Lanoteplase, a single-bolus, weight-adjusted agent, increased coronary patency at 60 and 90 minutes in a dose-dependent fashion. Coronary patency at 90 minutes was achieved more frequently with 120 kU/kg lanoteplase than alteplase. In this study, safety with lanoteplase and alteplase was comparable. InTIME-II, a worldwide mortality trial, will evaluate efficacy and safety with this promising new agent.

Adolescent↗
PubMed1998

Prior cytomegalovirus infection does not predict clinical outcome after percutaneous transluminal coronary angioplasty.

BACKGROUND: A direct association between human cytomegalovirus (HCMV) infection and the development of restenosis after coronary angioplasty has been suggested. The aim of this prospective study was to evaluate the value of HCMV serology in predicting the clinical outcome after percutaneous transluminal coronary angioplasty (PTCA). METHODS AND RESULTS: 112 patients undergoing elective PTCA were included in the study. HCMV antibody levels were measured by ELISA. Cardiac events within a follow-up period of 6 months after PTCA were defined as (1) progression or recurrence of anginal complaints and/or a positive exercise test; (2) restenosis that required repeat revascularization. 73% of PTCA patients were seropositive for HCMV. Successful PTCA was achieved in a total of 94 patients, who were followed for 6 months. In 31/94 patients (33%) cardiac events occurred and in 15/94 (16%), this could be related to restenosis. We found no statistically significant difference between seropositive and negative patients with respect to anginal complaints or the need for revascularization. There was no evidence of acute reactivation, since titers of anti-HCMV antibodies did not increase after PTCA. CONCLUSION: This study shows that the clinical outcome after PTCA is not related to the HCMV serostatus of the patient. Therefore, our data do not support the hypothesis that serological markers of HCMV infection are of clinical importance for the assessment of a patient's individual risk after PTCA. This does not preclude a role for local reactivation of HCMV at the site of angioplasty.

Acute Disease↗
PubMed1997

Percutaneous coronary angioscopic comparison of thrombus formation during percutaneous coronary angioplasty with ionic and nonionic low osmolality contrast media in unstable angina.

Patients with unstable coronary syndromes are more likely to have a lesion containing thrombus and have a higher procedural complication and restenosis rate. The aim of this study was to evaluate the effect of an ionic (ioxaglate) and a nonionic (iohexol) low osmolality contrast media on thrombus generation using percutaneous intracoronary angioscopy in patients with unstable angina undergoing percutaneous transluminal coronary angioplasty (PTCA). Thirty patients with unstable angina pectoris randomized to either ioxaglate or iohexol (15 patients in each group), underwent percutaneous intracoronary angioscopy before and after PTCA and 15 minutes after PTCA. Angioscopically visible thrombus was defined using the Ermenonville classification and the lesion divided into 3 zones-proximal, mid, and distal. Angiographic filling defects were seen in 3 patients before PTCA, and in 10 after PTCA. Angioscopically visible thrombus was seen in 10 patients before PTCA in the ioxaglate group and 8 in the iohexol group. After PTCA 5 patients (33.3%) in the ioxaglate and 11 (73.6%) in the iohexol group developed new thrombus, p = 0.028. Total thrombi before PTCA were 16 versus 13, after PTCA 25 versus 27, and at 15 minutes after PTCA 23 versus 25, ioxaglate versus iohexol respectively, p = NS. There was no correlation between type or extent of intimal dissection and angioscopically visible new thrombus formation. Angiography underestimated the incidence of intracoronary thrombus before and after PTCA. Nonionic low osmolality contrast medium was associated with significantly more patients developing angioscopically visible new thrombus. This has clinical implications in the choice of contrast medium used in PTCA, particularly in the setting of unstable angina.

Aged↗
PubMed1997

Coronary artery angioplasty with a helical autoperfusion balloon catheter.

The initial in-hospital and long-term clinical experience with a helical autoperfusion balloon catheter in the treatment of coronary artery disease is reported. This new catheter design allows blood to flow passively around the inflated balloon through a protected helical channel molded into the balloon surface. Twelve consecutive patients underwent PTCA. Continuous ST monitoring, heart rate, average peak distal coronary blood flow velocity (APV), coronary blood flow (CBF), dP/dt and systemic and pulmonary arterial pressures were determined during PTCA. During balloon inflation there were no hemodynamic changes, TIMI flow was 1.7 +/- 0.8, and APV was 39% of baseline. Luminal diameter stenosis improved from 61 +/- 17 to 29 +/- 13% (P < 0.05) following PTCA. Mean continuous inflation duration was 385 +/- 215 sec and 6/12 patients had > or = 7.5-min inflations. There were no in-hospital adverse cardiac events. One patient developed recurrent angina during 8 mo of follow-up and underwent successful PTCA of a restenotic lesion. We conclude that human plaques can be successfully dilated with a helical balloon catheter that provides autoperfusion and the ability to perform prolonged inflations with hemodynamic stability. A comparison of this PTCA catheter with standard balloon catheters is warranted.

Adult↗
PubMed1997

Minimally invasive coronary artery bypass grafting versus coronary angioplasty for isolated type C stenosis of the left anterior descending artery.

BACKGROUND: Isolated stenosis of the left anterior descending coronary artery can be treated with medication, percutaneous transluminal coronary angioplasty, or coronary artery bypass grafting. Recently a new treatment has been developed, which is called minimally invasive direct coronary artery bypass grafting. This new treatment is a modification of the conventional bypass operation and is performed through a small anterolateral thoracotomy without cardiopulmonary bypass. METHODS: To compare minimally invasive bypass with angioplasty, we evaluated in-hospital results and 1-year follow-up in 181 consecutive patients with isolated type C stenosis of the left anterior descending coronary artery between January 1995 and July 1996. Of these patients, 71 underwent minimally invasive bypass and 110 angioplasty. Preoperative characteristics were not significantly different between the two groups. RESULTS: In-hospital death, periprocedural myocardial infarction, emergency reoperation by means of conventional coronary bypass grafting, use of an intraaortic balloon pump, and cerebrovascular accidents were not significantly different between the two groups. At 1-year follow-up, survival was not significantly different in the two groups (minimally invasive bypass 95.7% +/- 0.2% vs angioplasty 95.3% +/- 0.2%; p = 0.89), whereas freedom from repeated revascularization was significantly more common in the group undergoing minimally invasive bypass (bypass 96.9% +/- 0.2% vs angioplasty 67.6% +/- 0.5%; p < 0.001). This study shows that the need for repeated revascularization, and therefore the use of health care resources, is significantly less with minimally invasive bypass than with angioplasty in patients with isolated type C stenosis of the left anterior descending coronary artery.

Angioplasty, Balloon, Coronary↗
PubMed1997

Analysis of atrial sensed far-field ventricular signals: a reassessment.

Accurate detection of the spontaneous far-field ventricular signal may be used to determine the ventricular activation, and hence, the interval from atrial stimulus to the ventricular R wave (AR interval) using a standard atrial pacing lead. This can be useful in developing a physiological atrial rate responsive (AAIR) pacemaker and in further improving DDD(R) pacing algorithms. In order to better characterize the atrial sensed far-field ventricular signal, 200 consecutive patients undergoing pacemaker implantation were studied. The amplitude of the far-field ventricular signal was significantly smaller than that of the atrial deflection. In all recordings, the slew rate of the atrial deflection was larger than that of the far-field ventricular signal. Subdivision of the recordings by electrode position, pocket location, or QRS duration on the surface ECG resulted in significantly different signal characteristics. The amplitude and slew rate of the far-field ventricular signal were significantly smaller in bipolar versus unipolar sensing. Atrial sensed far-field ventricular recordings could also be obtained in the case of ventricular pacing. Our results indicate that accurate sensing of the far-field ventricular signal from an atrial pacing lead is conceivable in most patients. The different signal characteristics in relation to parameters, such as electrode position, sensing mode, and pocket location, may be useful in determining the optimal conditions for signal sensing.

Cardiac Pacing, Artificial↗
PubMed1996

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty.

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty (PTCA)-with an autoperfusion balloon or active system-facilitates prolonged balloon inflation. Prolonged inflations may tack up intimal dissections and improve the primary angioplasty result in complex lesions. Additionally, distal perfusion may reduce the likelihood of cardiogenic shock during high-risk PTCA. Autoperfusion balloons are most frequently used to treat acute or threatened closure. There currently is no prospective clinical study showing that stent implantation for this complication is more successful and more cost-effective. The blood flow rates through autoperfusion balloons may not abolish myocardial ischemia, and higher flow rates can often be achieved with pumps. Therefore, during high-risk PTCA, pumps may be preferred to prevent hemodynamic collapse. Clinical application of perfusion pumps is hampered by the risk for mechanical hemolysis during prolonged perfusion and the high velocity of the bloodstream that exits the PTCA catheter, causing distal vessel wall trauma.

Angioplasty, Balloon, Coronary↗
PubMed1996

Continued benefit of coronary stenting versus balloon angioplasty: one-year clinical follow-up of Benestent trial. Benestent Study Group.

OBJECTIVES: This study sought to determine the 1-year clinical follow-up of patients included in the Benestent trial. BACKGROUND: The Benestent trial is a randomized study comparing elective Palmaz-Schatz stent implantation with balloon angioplasty in patients with stable angina and a de novo coronary artery lesion. Seven-month follow-up data have shown a decreased rate of restenosis and fewer clinical events in the stent group. It is not established whether this favorable clinical outcome is maintained for longer periods or whether coronary stenting defers restenosis and its subsequent clinical manifestations. METHODS: To clarify this uncertainty, we updated clinical information on all but 1 of 516 patients enrolled in the Benestent trial (257 in balloon group, 259 in stent group) at least 12 months after the intervention. Major clinical events (primary clinical end point) were tabulated according to the intention to treat principle and included death, the occurrence of a cerebrovascular accident, myocardial infarction, the need for bypass surgery or a further percutaneous intervention in the previously treated lesion. RESULTS: After 1 year, no significant differences in mortality (1.2% vs. 0.8%), stroke (0.0% vs. 0.8%), myocardial infarction (5.0% vs. 4.2%) or coronary bypass graft surgery (6.9% vs. 5.1%) were found between the stent and balloon angioplasty groups, respectively. However, the requirement for a repeat angioplasty procedure was significantly lower in the stent group (10%) than the balloon angioplasty group (21%, relative risk [RR] 0.49, 95% confidence interval [CI] 0.31 to 0.75, p = 0.001), and overall primary end points were less frequently reached by stent group patients (23.2%) than those in the balloon group (31.5%, RR 0.74, 95% CI 0.55 to 0.98, p = 0.04). No differences were found between groups with respect to functional class angina and prescribed medication at the time of follow-up. CONCLUSIONS: These clinical follow-up data show that the benefit of elective native coronary artery stenting in patients with stable angina is maintained to at least 1 year after the procedure and results in a significantly reduced requirement for repeat intervention.

Angina Pectoris↗
PubMed1994

Autoperfusion balloon versus stent for acute or threatened closure during percutaneous transluminal coronary angioplasty.

Efficacy and major clinical end points were compared in 61 patients treated with a Stack autoperfusion balloon versus 36 patients who received a Palmaz-Schatz stent for acute or threatened closure during coronary angioplasty. The groups were comparable regarding baseline clinical characteristics. Procedural success was achieved in 43 patients (70%) treated with an autoperfusion balloon versus 34 patients (94%) who received a stent (p < 0.02). Emergency bypass surgery was performed in 13 patients (21%) with the autoperfusion balloon versus none of the patients with a stent (p < 0.001). In the stent group, 3 patients (8%) died (p < 0.05); 2 deaths were caused by thrombotic reclosure, and 1 patient died after unsuccessful stent delivery. Subacute reclosure during hospitalization occurred in none of the patients with autoperfusion versus 8 patients with the stent (22%) (p < 0.0002). Therefore, the number of patients with successful stent implantation at discharge decreased to 26 (72%). At 3-month follow-up in all patients with a successful intervention, reclosure or angiographic restenosis (> 50%) occurred in 13 patients with autoperfusion (30%) versus 3 patients with stents (12%) (p = NS). There was no difference in event-free survival during follow-up. Thus, both interventions were equally successful in the treatment of acute and threatened closure. More emergency surgery was performed in the autoperfusion balloon group, whereas a higher subacute reclosure rate was seen in the stent group. At 3-month follow-up, there were no significant differences regarding reclosure, restenosis, and event-free survival.

Aged↗
PubMed1994

Serial angioscopic and angiographic observations during the first hour after successful coronary angioplasty: a preamble to a multicenter trial addressing angioscopic markers for restenosis.

Percutaneous coronary angioscopy was used in 13 patients in a pilot study to assess the intracoronary changes that occur during the first hour after balloon angioplasty (PTCA). The dilated segment was studied with 4.5F angioscopes and with quantitative coronary angiography (QCA) immediately after PTCA and at 15-minute intervals for up to 1 hour after PTCA. Significant progression of intimal dissection and thrombus formation could be demonstrated with angioscopy. These dissections and thrombi remained undetected with angiography, which only showed haziness. Thus through its superior sensitivity to intimal damage and thrombus, coronary angioscopy can reveal important intravascular events that apparently occur even after successful PTCA. The relation of such angioscopic observations to restenosis will be addressed in a subsequent multicenter study.

Angioplasty, Balloon, Coronary↗
PubMed1994

Angioscopic versus angiographic detection of intimal dissection and intracoronary thrombus.

OBJECTIVES: This study was undertaken to compare coronary angioscopy with angiography for the detection of intimal dissection and intracoronary thrombus. BACKGROUND: It has been demonstrated previously that coronary angioscopy provides more intravascular detail than cineangiography. Both imaging methods have to be compared directly to assess the additional diagnostic value of angioscopy. METHODS: The angiograms and videotapes of 52 patients who had undergone angioscopy were reviewed independently by two observers unaware of other findings. Classic angiographic definitions were used for dissection and thrombus. Angioscopic dissection was defined as visible cracks or fissures on the lumen surface or mobile protruding structures that are contiguous with the vessel wall. Angioscopic thrombus was defined as a red, white or mixed red and white intraluminal mass. RESULTS: Angiography and angioscopy were in agreement in 40.4% of cases in the absence of thrombus and in 11.5% in the presence of thrombus. No fewer than 25 (48.1%) angioscopically observed thrombi remained undetected at angiography. With angioscopy as the standard, although the specificity of angiography for thrombus was 100%, sensitivity was very low at 19%. Angioscopic dissection was present in 40 patients (76.9%) versus angiographic dissection in 15 patients (28.8%). With regard to dissection, there was no correlation between the two imaging methods (r phi = 0.15, p = 0.29). CONCLUSIONS: Coronary angiography underestimates the presence of intracoronary thrombus. Angioscopy and angiography are complementary techniques for detecting and grading intimal dissections.

Adult↗
PubMed1994

The 'Ermenonville' classification of observations at coronary angioscopy--evaluation of intra- and inter-observer agreement. European Working Group on Coronary Angioscopy.

A European coronary angioscopy working group has been established to create and evaluate a classification system for angioscopic observation. The 'Ermenonville' classification features items, graded in 3-5 categories, such as lumen diameter, shape of narrowing, colours of surface, atheroma, dissection, thrombus, etc. Inter- and intra-observer agreement on the interpretation of angioscopic images, using this classification system, was studied within the working group. Kappa values for chance-corrected intra-observer agreement of the diagnostic items were 0.51-0.67. The mean kappa values for inter-observer agreement were very low at 0.13-0.29. The important items, such as red thrombus and dissection were studied after recoding as either present or absent. These items proved to have a good intra-observer agreement, and an acceptable inter-observer agreement after recoding. Other angioscopic diagnoses should be made with caution. Multicentre angioscopy studies should make use of an angioscopy core laboratory. A set of definitions for coronary angioscopy is proposed, and this working group will re-evaluate observer agreements using these definitions.

Angioscopy↗