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Clemens von Birgelen

Publications and source records attributed to Clemens von Birgelen.

At least 19 recordsLinked to original sources
PubMed2006

Relation between plaque progression and low-density lipoprotein cholesterol during aging as assessed with serial long-term (> or =12 months) follow-up intravascular ultrasound of the left main coronary artery.

Because of the clinical benefit of lipid lowering in older patients, we hypothesized that the relation between low-density lipoprotein (LDL) cholesterol serum levels and coronary plaque progression may persist throughout aging. We analyzed serial intravascular ultrasound (IVUS) data of 60 left main stems (18 +/- 9 months apart) and evaluated the relation between LDL cholesterol levels and coronary plaque progression at different ages. The population (n = 60) was divided into 3 groups according to age: tertile 1 (n = 20) was a mean age of 48 +/- 6 years (median 51, range 33 to 55), tertile 2 (n = 20) was a mean age of 58 +/- 2 years (median 59, range 55 to 61), and tertile 3 (n = 20) was a mean age of 66 +/- 6 years (median 65, range 61 to 83). Between groups, there was no significant difference in non-age-related demographics, clinical data, lipid profiles, or medications (e.g., statins). There was a positive linear relation between LDL cholesterol and annual changes in plaque plus media area in all age tertiles, which was statistically significant in tertiles 2 and 3 (r = 0.56, p <0.01; r = 0.50, p <0.02) and showed a strong trend in tertile 1 (r = 0.41, p = 0.07). The estimated LDL cholesterol thresholds, which, as determined by regression analysis, would correspond to no plaque progression, were 74, 60, and 78 mg/dl, respectively, in tertiles 1, 2, and 3. In conclusion, serial IVUS data in left main coronary arteries suggest that the relation between LDL cholesterol serum levels and plaque progression persists during aging.

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PubMed2006

Relation between lipoprotein(a) and fibrinogen and serial intravascular ultrasound plaque progression in left main coronary arteries.

OBJECTIVES: Patients with elevated lipoprotein(a) [Lp(a)] and fibrinogen levels have an increased risk of coronary heart disease and adverse cardiovascular events. There is evidence that coronary plaque progression is linked to a higher risk for future cardiovascular events. BACKGROUND: There are no data demonstrating a relation between Lp(a), fibrinogen, and directly measured coronary plaque progression over time. METHODS: We performed a retrospective analysis of serial intravascular ultrasound (IVUS) studies of 60 left main stems (18 +/- 9 months apart) to evaluate plaque progression in relation to Lp(a) and fibrinogen levels and association with adverse cardiovascular events. RESULTS: There was a positive correlation between Lp(a) (r = 0.58; p < 0.0001), fibrinogen (r = 0.48; p < 0.0001), and changes in plaque-plus-media area. Patients with plaque progression (n = 41) had higher Lp(a) (30 +/- 26 mg/dl vs. 14 +/- 9 mg/dl; p < 0.0012) and fibrinogen (295 +/- 88 mg/dl vs. 240 +/- 72 mg/dl; p = 0.019) levels than patients with plaque regression (n = 19). Multivariate linear regression analysis showed Log Lp(a) (regression coefficient = 9.45; p = 0.0008) but not fibrinogen to be independently associated with plaque progression. A total of 19 patients suffered from adverse cardiovascular events; they had higher Lp(a) (44 +/- 30 mg/dl vs. 16 +/- 12 mg/dl; p < 0.0001) and fibrinogen (342 +/- 73 mg/dl vs. 248 +/- 76 mg/dl; p < 0.0001) levels. Multivariate logistic regression analysis showed Log Lp(a) (odds ratio 10.20, 95% confidence interval 2.36 to 44.13; p = 0.0019) and fibrinogen (odds ratio 1.01, 95% confidence interval 1.00 to 1.03; p = 0.018) were independently associated with adverse cardiovascular events. CONCLUSIONS: Serial IVUS showed a positive correlation between Lp(a) and fibrinogen levels and plaque progression. Lp(a), but not fibrinogen, remains independently associated with plaque progression. In addition, the present data suggest a considerable incremental value of Lp(a) in predicting cardiovascular risk.

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PubMed2006

Relation between baseline plaque burden and subsequent remodelling of atherosclerotic left main coronary arteries: a serial intravascular ultrasound study with long-term (> or =12 months) follow-up.

AIMS: Glagov's histopathological observation and non-serial intravascular ultrasound studies (IVUS) concluded that compensatory coronary remodelling diminishes as 40% atherosclerotic plaque burden is reached. We tested this hypothesis with serial IVUS. METHODS AND RESULTS: Serial IVUS examinations of 46 atherosclerotic non-stenotic left main stems (18+/-8 months apart) were analysed to assess the relation between baseline plaque burden (=plaque+media area/vessel area) vs. serial remodelling (=vessel area at baseline - at follow-up). There were 25 plaques with baseline plaque burden <40% (30.1+/-6.6%, group A) and 21 plaques with baseline plaque burden > or =40% (46.1+/-5.8%, group B). There was no relation between baseline plaque burden vs. subsequent changes in vessel area overall (r=0.07, P=0.7), for group A (r=0.03, P=0.6), and group B (r=0.01, P=0.8). The frequency of positive serial remodelling (vessel area increase) vs. negative or intermediate serial remodelling (no change or decrease) were similar in group A [17 (68%) vs. 8 (32%)] and group B lesions [18 (86%) vs. 3 (14%)] (P=0.2). CONCLUSION: IVUS demonstrates that serial coronary remodelling is not related to baseline plaque burden. Lesions with baseline plaque burden <40% may subsequently show a lack of compensation or frank arterial shrinkage, whereas lesions with baseline plaque burden >40% may continue to develop compensatory enlargement.

Coronary Artery Disease↗
PubMed2006

Dedicated calibration formulas permit correction of differences between measurements by different IVUS devices as demonstrated in atherosclerotic human coronary arteries in vitro.

Serial intravascular ultrasound (IVUS) measurements of coronary vessel dimensions are major endpoints of studies focusing on pharmacological interventions, efficiency of drug eluting stents, and vascular remodeling. In serial studies measurement variability among different IVUS devices may cause substantial misinterpretation and error. We analyzed 33 human coronary plaques in vitro using two different IVUS systems (mechanical IVUS system with a 40 MHz Atlantis SR catheter; solid-state electronic IVUS system with a 20 MHz Invision catheter) and repeatedly measured the total vessel, lumen, and plaque + media cross-sectional area and plaque burden (plaque + media area divided by total vessel area). Between the "raw" measurements made by the two devices, there was a significant difference for both plaque + media area (2.35+/-1.86 mm(2), P < 0.01) and plaque burden (5.39+/-3.68%, P < 0.05). Measurements were then corrected by use of recently introduced calibration formulas; as a result the differences decreased significantly for all IVUS parameters measured ( P < 0.0001). After correction, the remaining differences between the corrected mechanical and solid-state IVUS measurements similar to differences between repeated measurements with the same IVUS device (i.e., the intraobserver variability). Thus, in serial studies the use of different IVUS devices at index and follow-up procedure may introduce a substantial error as a result of system-related differences. The application of dedicated calibration formulas allows for correction for these differences by decreasing such differences to the level of intraobserver variability.

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PubMed2006

Remodeling index compared to actual vascular remodeling in atherosclerotic left main coronary arteries as assessed with long-term (> or =12 months) serial intravascular ultrasound.

OBJECTIVES: We present the remodeling index (RI) versus serial intravascular ultrasound (IVUS) data. BACKGROUND: The RI, derived by comparing lesion external elastic membrane (EEM) cross-sectional area versus the reference at one time point, is used in various IVUS studies as a substitute of true remodeling (change in EEM over time), assuming that it represents true remodeling. METHODS: We studied 46 non-stenotic left main arteries using serial IVUS (follow-up 18 +/- 8 months). Plaques were divided into subgroups according to the follow-up RI: follow-up RI >1 (n = 27) versus follow-up RI < or =1 (n = 19). RESULTS: Lesions with a follow-up RI >1 had an increase in lumen despite an increase in plaque because of an increase in EEM. Conversely, lesions with a follow-up RI < or =1 had a reduction in lumen as a result of both a plaque increase and EEM decrease. Overall, the follow-up RI correlated directly with changes in lesion site EEM (baseline-to-follow-up). Although there was no correlation between the follow-up RI and changes in reference EEM area, changes in reference EEM area did correlate directly with changes in lesion EEM area. In nearly 90% of lesions with a follow-up RI >1, there was a previously documented increase in EEM area. Using multivariate linear regression analysis, the follow-up RI was dependent on the baseline RI, the increase in lesion EEM area, and the decrease in reference EEM area. The follow-up RI was not dependent on changes in lesion plaque area. CONCLUSIONS: The vast majority of left main lesions with a remodeling index >1 had evidence of a previous increase in lesion-site EEM area.

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PubMed2006

Impact of intraventricular conduction delay on coronary haemodynamics: a study with intracoronary Doppler in patients with bundle branch blocks and normal coronary arteries.

AIMS: The impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) on myocardial perfusion is not completely understood as data are often blurred by underlying cardiac disease. The present study investigates whether conduction delays per se affect coronary perfusion-an indirect measure of myocardial oxygen demand. METHODS AND RESULTS: Intracoronary Doppler and ultrasound were performed in 8 patients with RBBB, 10 patients with LBBB, and 10 control subjects. All patients had angiographically normal coronary arteries and normal left ventricular function. Baseline (bAPV) and adenosine-induced hyperaemic average flow velocity and coronary flow velocity reserve (CFVR) were measured in left anterior descending arteries. Intravascular ultrasound showed no difference in lumen cross-sectional area and plaque burden between groups. Patients with RBBB and LBBB had higher bAPV values than controls (19.0 +/- 4.9, 21.9 +/- 5.1, and 14.6 +/- 2.4 cm/s, respectively; ANOVA P = 0.003). There was no difference between patients with LBBB and RBBB compared with controls in CFVR (2.8 +/- 0.5, 3.0 +/- 1.0, and 3.4 +/- 0.7, respectively; ANOVA P = 0.21). CONCLUSION: Bundle branch blocks, in particular LBBB, are associated with an increased coronary flow velocity, which indicates enhanced myocardial oxygen demand on the basis of mechanoenergetic disturbance. This may contribute to the unfavourable outcome of patients with intraventricular conduction delay.

Adenosine↗
PubMed2004

Determinants of coronary blood flow in humans: quantification by intracoronary Doppler and ultrasound.

The direct determinants of coronary flow are lumen area and blood flow velocity; however, the precise mechanisms that control these factors are not fully understood. The aim of the present study was to assess by which mechanisms lumen area and coronary flow velocity interact with hemodynamic and morphometric factors, thereby influencing coronary flow. Intracoronary Doppler and ultrasound measurements were performed in 28 patients without coronary lumen irregularities. Flow velocity and lumen cross-sectional area were measured in the proximal segments of all three coronary arteries. Global lumen cross-sectional area and global flow were obtained by adding up the values of all three coronary arteries. Left ventricular mass was assessed by echocardiography. Stress-mass-heart rate and pressure-rate products reflecting myocardial oxygen demand were calculated. Global coronary flow increased during adenosine-induced hyperemia from 197 +/- 72 to 637 +/- 204 ml/min (P < 0.001). Global coronary flow closely correlated with the stress-mass-heart rate product (r = 0.62; P < 0.001). Looking at the two constituents of flow separately, global coronary cross-sectional area was closely related to left ventricular muscle mass (r = 0.61; P < 0.001), whereas mean coronary flow velocity at rest showed a strong linear relation with the pressure-rate product (r = 0.64; P < 0.001). There was no interaction between cross-sectional area and blood flow velocity in any of the coronary vessels. Coronary lumen size and flow velocity, the two determinants of coronary flow, are principally determined by different physiological factors. Long-term flow adaptation is achieved by an increase in coronary lumen size, whereas short-term myocardial oxygen requirements are met by changes in resting flow velocity.

Blood Flow Velocity↗
PubMed2004

Relationship between cardiovascular risk as predicted by established risk scores versus plaque progression as measured by serial intravascular ultrasound in left main coronary arteries.

BACKGROUND: Intravascular ultrasound (IVUS) is increasingly used as an end point in studies aimed at reducing progression or inducing regression of coronary artery disease. However, data linking serial changes by IVUS with clinical outcomes are scarce. METHODS AND RESULTS: In the absence of a validated risk score for secondary prevention, we compared 3 established risk scores for primary prevention--PROCAM, SCORE, and Framingham--with plaque progression and lumen reduction as assessed with serial IVUS (follow-up, 18+/-9 months) in atherosclerotic left main coronary arteries of 56 patients with established atherosclerosis. For all 3 algorithms, patients at highest estimated risk of events showed greater plaque progression than patients at lowest risk (P<0.05 to <0.01). There were positive linear relationships between the risk of clinical events and plaque progression (r=0.41 to 0.60; P<0.002 to <0.0001). This translated into a greater decrease in lumen dimensions with increasing risk (P<0.05, PROCAM and SCORE). Risk prediction using the PROCAM algorithm showed the strongest relation with serial IVUS. During follow-up, 18 patients suffered from adverse cardiovascular events; these patients had an annual plaque progression that was significantly greater than other patients (25.2+/-19.4% versus 5.9+/-15.6%, P<0.001). CONCLUSIONS: There was a positive linear relationship between the estimated risk of clinical events derived from all 3 established risk-score algorithms and the extent of plaque progression measured by serial IVUS. This translated into stenosis progression (reduction in lumen dimensions) with increasing clinical risk.

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PubMed2004

Value of plasma fibrin D-dimers for detection of acute aortic dissection.

OBJECTIVES: The purpose of this research was to assess the value of systemic inflammatory biomarkers in the detection of acute aortic dissection (AD). BACKGROUND: Rapid diagnosis and initiation of treatment is pivotal for patients with acute AD. So far, there is no laboratory test to aid the diagnosis. METHODS: Plasma fibrin D-dimers, white blood cell (WBC) count, C-reactive protein (CRP), and fibrinogen were determined in 64 chest-pain (CP) patients (acute AD, n = 16; pulmonary embolism [PE], n = 16; acute myocardial infarction [AMI], n = 16; non-cardiac CP, n = 16); 32 asymptomatic patients with chronic AD served as a control group. RESULTS: All acute AD patients showed highly elevated D-dimer values that were similar to PE patients (2,238 +/- 1,765 microg/l vs. 1,531 +/- 837 microg/l, p = 0.15) but significantly higher than in chronic AD, AMI, or CP patients (p < 0.001). The WBC count was significantly increased in patients with acute AD compared with the other groups (p < 0.001); in addition, CRP values differed only non-significantly from PE patients(p = 0.71). There were no differences in the fibrinogen levels between the groups. CONCLUSIONS: D-dimers are highly elevated in both acute PE and acute AD. Patients with acute AD show significant systemic inflammatory reactions. Measurement of D-dimers may be a valuable addition to the current diagnostic work-up of patients with suspected AD.

Acute Disease↗
PubMed2004

Aortoesophageal fistula secondary to stent-graft repair of the thoracic aorta.

PURPOSE: To report the incidence and management of aortoesophageal fistula (AEF) secondary to endovascular stent-graft repair of the descending thoracic aorta. METHODS: A retrospective review was conducted of patients treated at our facility between July 1999 and June 2003. During this interval, 60 patients (46 men; average age 66+/-10 years) underwent thoracic aortic stent-graft placement for a variety of pathologies. RESULTS: AEF occurred in 3 (5%) patients. One 62-year-old man presented with recurrent back pain and fever and died suddenly due to fatal exsanguination; the AEF was revealed at necropsy. The other 2 patients (both women) presented with hematemesis after endovascular repair of thoracic aortic aneurysms. AEF was detected by esophagogastroduodenoscopy. Both patients were treated conservatively, as open surgical repair was refused because of their general condition. Both patients developed severe mediastinitis and died after 5 weeks and 10 months, respectively. CONCLUSIONS: Aortoesophageal fistula is, in our experience, a catastrophic complication of endovascular stent-graft placement. Treatment options are very limited, as these patients are usually not candidates for open surgery. Outcome under conservative management is, however, almost invariably fatal.

Aged↗
PubMed2004

Impact of gender on femoral access complications secondary to application of a collagen-based vascular closure device.

BACKGROUND: Vascular complications at the femoral access site continue to be a significant problem after cardiac catheterization procedures. It was the aim of the present study to assess the impact of gender on the incidence of severe femoral access complications following the application of a collagen-based vascular closure device after transfemoral catheterization procedures. METHODS: A total of 1,294 consecutive patients (977 male, 317 female) underwent closure of femoral access sites with 8F collagen-based vascular closure devices (Angioseal) immediately after diagnostic or interventional coronary catheterization procedures, independently of the coagulation status. All patients were closely monitored for the occurrence of complications during the following 24 hours. RESULTS: Between male and female patients, there was no difference in the technical performance of the device with successful deployment being achieved in 96.7% and 95.9%, respectively (p=0.60). Severe access complications were found to be significantly higher in female versus male patients (1.6% vs. 0.2%; Odds ratio 7.7, 95% confidence interval 1.5-40.1; p=0.015), although similar accomplishment of an immediate hemostasis was seen in 92.8% and 92.4% of male and female patients (p=0.98). CONCLUSION: Women show a significantly increased risk of developing severe femoral access complications secondary to the application of a collagen-based vascular closure device, although the overall incidence of these complications is relatively low. We speculate that the increased risk in women may be related to smaller arterial dimensions, which could be evaluated by femoral angiography prior to deployment of a closure device.

Adult↗
PubMed2003

Relation between progression and regression of atherosclerotic left main coronary artery disease and serum cholesterol levels as assessed with serial long-term (> or =12 months) follow-up intravascular ultrasound.

BACKGROUND: The relation between serum lipids and risk of coronary events has been established, but there are no data demonstrating directly the relation between serum low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol versus serial changes in coronary plaque dimensions. METHODS AND RESULTS: We performed standard analyses of serial intravascular ultrasound (IVUS) studies of 60 left main coronary arteries obtained 18.3+/-9.4 months apart to evaluate progression and regression of mild atherosclerotic plaques in relation to serum cholesterol levels. Overall, there was (1) a positive linear relation between LDL cholesterol and the annual changes in plaque plus media (P&M) cross-sectional area (CSA) (r=0.41, P<0.0001) with (2) an LDL value of 75 mg/dL as the cutoff when regression analysis predicted on average no annual P&M CSA increase; (3) an inverse relation between HDL cholesterol and annual changes in P&M CSA (r=-0.30, P<0.02); (4) an inverse relation between LDL cholesterol and annual changes in lumen CSA (r=-0.32, P<0.01); and (5) no relation between LDL and HDL cholesterol and the annual changes in total arterial CSA (remodeling). Despite similar baseline IVUS characteristics, patients with an LDL cholesterol level > or =120 mg/dL showed more annual P&M CSA progression and lumen reduction than patients with lower LDL cholesterol. CONCLUSIONS: There is a positive linear relation between LDL cholesterol and annual changes in plaque size, with an LDL value of 75 mg/dL predicting, on average, no plaque progression. HDL cholesterol shows an inverse relation with annual changes in plaque size.

Cholesterol↗
PubMed2003

Preintervention arterial remodeling affects vessel stretch and plaque extrusion during coronary stent deployment as demonstrated by three-dimensional intravascular ultrasound.

The mechanisms of lumen enlargement during stent implantation may be significantly affected by arterial remodeling. To assess effects of lesion remodeling, we performed 3-dimensional intravascular ultrasound (IVUS) analyses in 55 coronary lesions before and after deployment of balloon-expandable stents. Standard quantitative analysis was performed, and arterial remodeling was assessed by the remodeling index (target site divided by mean of proximal and distal reference segment vessel areas), which classified lesions into group A (remodeling index < or =1, negative or intermediate remodeling, n = 40) or group B (remodeling index >1, positive remodeling, n = 15) lesions. Characteristics of the 55 patients and the interventional procedures were similar in the 2 groups. IVUS demonstrated that stenting resulted in increased lumen and vessel dimensions and in a reduced plaque size (p < or =0.001 each) in both group A and group B lesions. The extent of lumen increase inside the stents was almost identical, but resulted from different mechanisms: (1) vessel stretch was greater in group A (p <0.002 at minimum lumen site); (2) plaque compression (or embolization) tended to be greater in group B (p = 0.05, along entire stented segment); (3) plaque redistribution within the stent was observed in both groups (p <0.005 both); and (4) significant (p <0.01) plaque extrusion into the distal reference segment was found in group B only. Thus, the remodeling pattern of coronary lesions has a significant impact on the mechanisms of lumen enlargement during stent deployment. Lesions with positive remodeling show more plaque extrusion into the distal reference and less stent-induced vessel stretch than those with negative remodeling.

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PubMed2003

Impact of moderate lesion calcium on mechanisms of coronary stenting as assessed with three-dimensional intravascular ultrasound in vivo.

Axial plaque redistribution is an important mechanism of lumen enlargement after stenting of noncalcified lesions. To assess effects of lesion calcification on mechanisms of coronary stenting, we analyzed 55 lesions with noncircumferential calcification with 3-dimensional intravascular ultrasound (IVUS) (standard qualitative and quantitative analyses) before and after implantation of balloon-expandable stents. Thirty-two plaques (58%) showed arcs of calcium <120 degrees of vessel circumference (group A), whereas 23 lesions (42%) contained arcs of calcium > or =120 degrees of vessel circumference (group B). In the entire cohort of 55 lesions, as well as groups A and B, which were studied separately, both single-slice IVUS analysis (performed at minimum lumen site before intervention) and mean stented segment IVUS analysis showed an increase in lumen and vessel area and a decrease in plaque area (p <0.001). The magnitude of lumen and vessel increase and of plaque decrease was similar in both groups. Group A lesions showed significant plaque extrusion into the distal reference segment that was not observed in group B (increase in plaque area of 1.3 +/- 1.9 vs 0.1 +/- 2.0 mm(2), p <0.04). Stenting did not alter plaque area of the proximal reference segment in either group. In addition, there was an increase in vessel area of the distal reference of both groups, indicating that stent-induced vessel expansion observed within the lesion also affected the distal reference. Thus, longitudinal plaque redistribution and vessel expansion contribute to increased lumen dimensions during stenting of lesions with varying amounts of calcium; however, marked plaque extrusion was found only in lesions with a calcium arc of <120 degrees.

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