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Biomedical subjects

M Haude

Publications and source records attributed to M Haude.

At least 127 records · Page 7Linked to original sources
PubMed1995

[Reconstruction methods for 3D imaging and quantification of intracoronary ultrasound cross-sectional images using biplanar fluoroscopy. Initial experiences in vitro and in vivo].

In this investigation, we studied the feasibility of 3D-reconstruction from 2D cross-sectional intracoronary ultrasound images. A computer-aided, automated 3D-reconstruction was used to generate cylindrical and sagittal format of vessels in vitro (n = 9) and in vivo (n = 48). Ultrasound 2D-images were acquired with a 20 MHz mechanical intracoronary ultrasound catheter (Boston Scientific). A slow pullback (about 1 mm/s) of the catheter was performed during continuous recording of the ultrasound images. The recorded 2D-images were then fed to an image processing computer. Correction and scaling of the axial vessel dimensions was performed by the assessment of the catheter position in the simultaneously recorded biplane fluoroscopy. Digitized data were then processed to 3D-images with use of voxel space modeling. The 3D-views from any plane can be reconstructed. The in-vitro study demonstrated that the reconstructed images were able to correctly portray the pathological changes of the vessel wall in all specimen as proved by pathologic examination. In the in-vivo study, 3D-reconstruction provided not only a spatial visualization of the coronary arterial disorders (such as coronary aneurysm, coronary dissection, spontaneous plaque rupture etc.) but also provides the potential to quantify the mass of lesions. By combining sagittal and cylindrical views, 3D-reconstruction enables longitudinal and orthogonal imaging of the both the vessel lumen and vessel wall, therefore, it has the advantage of cross-sectional viewing as obtained from intracoronary ultrasound and the longitudinal viewing as derived from coronary angiography. These preliminary results of the study indicate that 3D-reconstruction of coronary segments is a promising technique for studying coronary artery disease. Analysis can be based not only on single or multiple cross-sectional images but also on vessel segments facilitating serial studies as for instance studies assessing the progression and regression of atherosclerosis.

Aortic Dissection↗
PubMed1995

[Alternative methods in interventional therapy of coronary heart disease].

Percutaneous high-frequency coronary rotablation using the rotablator is able to remove arteriosclerotic material from the vessel wall. A diamond-coated (30-80 microns) brass burr drill fastened to a flexible drive shaft rotating and tracking along a drill coaxial guide wire is used. The turbine rotates the drive shaft in excess of 150,000-190,000 rpm. High-frequency rotational angioplasty was successful in > 90% of patients, but in about 90% additional PTCA is necessary. No increase of bypass surgery compared to PTCA is observed. CK and CR-MB elevation is more often found than after PTCA. Vessel perforation is rarely observed. All vessels were open at 24-h control. The restenosis rate seems not be increased. The main indications for high-frequency rotational angioplasty are rigid and calcified sclerotic lesions which cannot be passed by conventional balloon catheters. Whether the restenosis rate can be reduced by this method will be judged in part by the COBRA study. In order to avoid acute complications of PTCA and to reduce restenosis rate, coronary stents were developed. Self-expandable and balloon expandable stents are available. It could be demonstrated that these stents can be used as a bail-out system and can block elastic recoil of coronary arteries. The major remaining problem is subacute closure of coronary vessels. In order to prevent thrombosis treatment with coumarine, acetylsalicylic acid, and dipyridamol is necessary. Coronary stents can be successfully delivered in more than 90% of the patients. In a highly selected patient group using single stents restenosis rate could be significantly reduced.

Angioplasty, Balloon, Coronary↗
PubMed1995

[Noninvasive evaluation of the patency of coronary vessel stents using electron beam tomography segment images with administration of contrast media].

The implantation of intracoronary stents is increasingly employed in interventional cardiology. Even with high-resolution x-ray equipment the tiny struts of stainless steel stents can usually not be visualized. Coronary angiography is required to prove stent patency, and correct localization and deployment of the stent can only be assessed with intravascular ultrasound. In this setting a non-invasive diagnostic method would be of great advantage to document patency of the stented vessel segment. Herein we describe two patients with stent implantation in whom contrast-medium-enhanced electron beam tomographic scanning was applied to check for vessel patency. A pathological finding with reduced contrast enhancement could be distinguished from a normal finding, as was confirmed subsequently as a highly obstructed and a patent stented vessel segment by angiography. Thus, for the first time an alternative non-invasive diagnostic method may provide information on patency of stented vessel segments and may be useful for sequential follow-up investigations.

Angina Pectoris↗
PubMed1995

Microscopic evaluation of an occluded intracoronary Palmaz-Schatz stent removed before coronary artery bypass grafting.

Intracoronary implantation of stent devices is a new interventional technique with a promising role in the treatment of acute coronary occlusions caused by intimal dissection and suboptimal results of percutaneous transluminal coronary angioplasty. However, the prolonged presence of stent material embedded in the arterial wall may generate unknown late consequences. Major complications consist of subacute to chronic occlusion and restenosis. To elucidate the underlying cause we removed an angiographically occluded intracoronary artery Palmaz-Schatz stent before coronary artery bypass grafting. Scanning electron microscopy showed thorough coating of the metal struts of the stent by normal neoendothelial cells. Side branches arising at the level of the stent were patent. According the specific angiographic feature thrombotic occlusion originated distally of the stent.

Aged↗
PubMed1994

Continuous coronary perfusion balloon catheters in coronary dissections after percutaneous transluminal coronary angioplasty. Acute clinical results and 6-months follow-up.

The purpose of the study was to evaluate prospectively the effect of a continuous perfusion balloon catheter ('High Flow CPC Mainz', Schneider/Pfizer Europe AG, CH-8052 Zurich, Switzerland) on tolerated inflation time during elective PTCA (n = 31), and its usefulness in cases of unsatisfactory morphological or functional results after PTCA (n = 42). Sixty-five patients were male, eight female; their mean age was 57.6 +/- 8.85 years. The target vessel was the LAD in 39 patients, the RCA in 29, the LCX in three, and bypass grafts in two. Seven patients had type A lesions, 44 type B and 22 type C, respectively. The target lesion was in the proximal third of the coronary artery in 41 patients, in the mid-third in 30, and in the distal third in two. Side branches were involved in 24 patients. The median size of the standard PTCA balloon was 3.00 mm and 3.5 mm for the CPC. Tolerated inflation time rose from 36 +/- 21 s to 213 +/- 108 s (P < 0.01). Additionally, the CPC catheter was used in 42 patients with symptomatic dissections (ST segment elevation, chest pain, or impaired contrast run-off) after PTCA. Wall wrapping by CPC was successful in 24 (57%) and unsuccessful in 18 (43%) patients. A significant difference was found for the inflation times tolerated between patients with successful (265 +/- 99 s) and unsuccessful wall wrapping (161 +/- 108 s; P < 0.01). Of the 18 patients with unsuccessful wall wrapping, 11 (61%) required an intracoronary stent, and six patients (30%) could be managed by medical treatment alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

Intravascular ultrasound imaging of angiographically normal coronary arteries: a prospective study in vivo.

Intravascular ultrasound imaging (IVUS) was performed to elucidate the discrepancy between clinical history and angiographic findings and to measure the diameter and area of the lumen of the normal left coronary artery in 55 patients who presented with chest pain but had normal coronary angiograms. The left coronary artery (LCA) was scanned with a 4.8F, 20 MHz mechanically rotated ultrasound catheter at 413 sites. Atherosclerotic lesions were identified at 72 (17%) sites in 25 patients. The mean (SD) (range) plaque area was 5.55 (3.56) mm2 (2-26 mm2) and it occupied 28.8 (9.6)% (13-70%) of the coronary cross sectional area. Calcification was detected at 24 (33%) atherosclerotic sites in nine patients. The correlation coefficients for the lumen dimensions measured at normal sites by IVUS and by angiography were r = 0.93 (SEE = 0.43) mm for lumen diameter and r = 0.89 (SEE = 4.27) mm2 for lumen area (both p < 0.001). 16 of the 30 patients in whom no atherosclerotic plaques were detected in the LCA lumen by IVUS had no risk factors of coronary artery disease. The cross sectional area of 90 consecutive images of left main coronary artery (LMCA), proximal left anterior descending coronary artery (proximal LAD), and mid LAD was measured in these 16 subjects. The mean (SEM) areas at end diastole were LMCA 17.33 (7.98) mm2; proximal LAD 13.56 (5.85) mm2; mid LAD 9.75 (4.67) mm2. During the cardiac cycle the cross sectional area changed by 10.2 (4.0)% in the LMCA, by 8.3 (4.7)% in the proximal LAD, and by 9.8 (4.0)% in the mid LAD. In 11 patients with plagues the change in cross sectional area in plague segments (5.8(3.1)%) was significantly lower than in the segments from patients without plagues (p < 0.001). Lumen area reached a maximum in early diastole rather than in late diastole. IVUS can imagine atherosclerotic lesions that are angiographically silent; it also provides detailed information about plague characteristics. The variation in coronary cross sectional area during the cardiac cycle should not be ignored during quantitative analysis. Maximum dimensions in normal segments are reached in early diastole. Further studies are needed to clarify the clinical significance of atherosclerosis detected by IVUS in patients presenting with chest pain but normal coronary angiography.

Adult↗
PubMed1994

Comparison of intravascular ultrasound and angiography in the assessment of myocardial bridging.

BACKGROUND: In autopsy, myocardial bridging is a common finding. With coronary angiography, a systolic compression, mainly of the left anterior descending coronary artery, is observed in 1% to 3% of the patients. Controversy exists concerning the functional importance of this finding. To obtain a functional insight into the myocardial bridging, intravascular ultrasound and intracoronary Doppler were performed. METHODS AND RESULTS: Intracoronary ultrasound and Doppler were performed in 14 patients with angiographic evidence of systolic vessel compression ("milking effect") in the left anterior descending coronary artery. The 4.8F, 20-MHz ultrasound catheter could not be advanced through the entire myocardial bridge segment in 6 of the 14 patients studied because the lumen was < 1.6 mm. In these patients, only the proximal parts of the bridge segment were scanned. The changes in cross-sectional shape during the cardiac cycle were determined for both the normal proximal segment and the bridge segment by use of a semiautomatic computer program. Intracoronary Doppler (20 MHz) was performed in 7 patients with a 3F catheter. A highly characteristic systolic eccentric or concentric compression with delayed relaxation in diastole of the myocardial bridging segment was clearly visualized in all patients. The cross-sectional lumen area variation was 40 +/- 25% in the bridging segments and 9 +/- 7% in the normal segments (P < .01). No atherosclerotic lesions were detected in the bridge or the distal segment in the 8 patients in whom the IVUS catheter was successfully advanced through the entire myocardial bridge. However, atherosclerotic plaques were found in the segments proximal to the bridge in 12 of 14 patients (86%). The resting mean flow velocity was 6.4 +/- 1.2 cm/s; the maximal mean flow velocity after intracoronary administration of 10 mg papaverine was 14.1 +/- 3.4 cm/s. The coronary flow velocity reserve was 2.2 +/- 0.7. A highly characteristic pattern showing a prominent peak in coronary velocity in early diastole was observed in 86% of patients, and this pattern was enhanced after injection of intracoronary papaverine. CONCLUSION: Intravascular ultrasound demonstrated a characteristic systolic compression of the bridge segments. The delayed compression release may explain the characteristic sharp early diastolic peak in coronary flow velocity found with intracoronary Doppler in vessels with myocardial bridging. Reduced coronary flow reserve may be related to this phenomenon, possibly explaining signs of ischemia detected in some of the patients, but may alternatively be a result of the presence of atherosclerosis in the segment proximal to the bridge in these patients.

Blood Flow Velocity↗
PubMed1994

[Therapy of cardiogenic shock in acute myocardial infarct].

Cardiogenic shock in acute myocardial infarction patients is the most common cause of in-hospital death. Various studies showed, that 60 to 100% of patients in cardiogenic shock will die, if no early reperfusion of their coronary artery could be established. The incidence of cardiogenic shock has decreased during the last years, most likely due to early thrombolytic therapy and administration of nitroglycerin. Reasons for cardiogenic shock are either necrosis of 40% or more of the left ventricular wall, right heart infarction, or complications which can be treated by the surgeon, like papillary muscle rupture, ventricular septal defect or rupture of the free ventricular wall. Diagnosis is based on clinical criteria, echocardiography, and on hemodynamic monitoring. The hemodynamic criteria for cardiogenic shock are a cardiac index of < 2.2/l, and an increased wedge pressure of > 18 mm Hg; additionally, diuresis is usually < 20 ml/h. Therapy can be divided into the following categories: a) pharmaceutical interventions to increase cardiac output like vasodilators or positive inotrope drugs; b) mechanical support systems; c) acute interventions with the aim of reperfusion; d) acute surgical interventions addressing complications like papillary muscle rupture, ventricular septal defect or rupture of the free ventricular wall. While steps a) and b) are able to stabilize the hemodynamical situation in patients with cardiogenic shock, they are rarely the definitive treatment. Point c), reperfusion of the coronary artery, can be divided in thrombolysis or acute PTCA. Thrombolysis failed to show a beneficial effect in most studies, either after intravenous or intracoronary application. On contrast, acute PTCA showed to be of great benefit in various studies with a technical success rate of 54 to 100% and a survival rate of patients from 58 to 100%. Thus, emergency PTCA is the treatment of choice in cardiogenic shock. Point d), surgical interventions can be divided in acute bypass grafting, which should be reserved for patients with severe multivessel disease, left main involvement, or failed PTCA. Furthermore, acute heart transplantation is effective, but will be possible in a minority of patients only. The last part of surgically manageable complications are surgery of papillary muscle rupture and ventricular septal defect. Results of early surgery in papillary muscle rupture or ventricular septal defects are much better than delayed interventions. Rupture of the free wall is usually a fatal event. In summary, the most successful therapy of cardiogenic shock is early emergency PTCA.(ABSTRACT TRUNCATED AT 400 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

[Quality management in the heart catheterization laboratory].

Quality management within the catheterization laboratory includes the quality control, the heart catheterization technique and the policy. Quality management is critical in the heart catheterization laboratory. Dedication of all members of the lab and computer personnel ensures high patient satisfaction. A continued quality improvement program is patient-orientated and requires good planning. One of the main emphasis in the catheterization lab is standardization which includes the patient preparation, the procedure itself, and the management. It is supported by teamwork including the economic aspect of prompt delivery of material and avoidance of complications. A continuous circle of treatment planes, performance, and check is regarded as the Deming cycle and leads to continuous improvement of quality. Important are both the avoidance and detection of complications. The reasons for any such have to be evaluated. It is recommended to follow the zero mistake hypothesis of Crosby, which means quality control by the lab supervisor, a quality consciousness, a quality measurement and quality improvement, as well as using a day to day quality improvement and to teach quality control. In Germany a quality control questionnaire was administered in an analysis of the current structure, function, and results of catheterization labs. Most important was the analysis of complications. The data were based on diagnostic catheterization in 1992, which included 140668 catheterizations in 83 laboratories. Thus, a mean of 1030 heart catheterizations was performed in each lab. In the mean, 200 catheterizations were performed by each doctor. In 19% of the labs digital imaging was exclusively performed. Major complications occurred with ventricular fibrillation in 0.36% (range 0.75%), resuscitation 0.18% (0.43%), persistent cerebrovascular accident 0.08% (0.24%), myocardial infarcts 0.19% (0.59%), aortic dissection 0.05% (0.22%). Mortality was 0.03% (0.08%). In heart catheterization laboratories quality management is one of the major goals for the future work. Only the continued improvement of quality and very good quality management ensure patient safety. Quality is the sum of technique and consciousness.

Cardiac Catheterization↗
PubMed1994

[Follow-up and characteristics of restenoses after coronary stent implantation in asymptomatic patients and patients with few symptoms].

Following coronary Palmaz-Schatz single stent implantation 50 patients had an angiographic follow-up after 4-6 and after 12 months. Quantitative angiography revealed that the restenosis process has finished 4-6 months after stent implantation in the majority of patients. In the present study, 6% had, however, developed symptomatic restenosis at 1-year follow-up. Detailed assessment of 15 patients revealed that the residual stenosis after stent implantation is most prominent at the stent edges, however, restenosis did occur in all segments in about the same amount. Analysis of several clinical and morphologic variables did not reveal any particular risk factor for the development of restenosis. The results of the present study do suggest that follow-up angiography should be performed 4-6 months after stent placement.

Adult↗
PubMed1993

[Restenosis after the implantation of Palmaz-Schatz vascular stents in the coronary arteries].

Restenosis rate after successful intracoronary implantation of Palmaz-Schatz stents in 100 patients (92 men, 8 women; mean age 57 +/- 11 years) was quantitatively assessed by angiography performed on average 5.3 +/- 0.3 months after the procedure. Restenosis was defined as a more than 50% decrease in lumen. Data from patients with acute or subacute thrombotic complications were excluded from the analysis. The restenosis rate of the total group was 22%. After placement of only one stent (n = 87) it was 17%, of multiple stents per lesion (n = 13) 54%. Restenosis rate after emergency implantation of a single stent (n = 23) was 17.4%, after elective single stent implantation (n = 64) 17.2%. There was no significant difference regarding treatment of new stenoses (n = 16), and recurrent stenosis (n = 48), namely 12.5% vs 18.8%. The following were risk factors for chronic restenosis after stent implantation: multiple stents (odds ratio [OR] 5.6; 95% confidence interval [CI]: 1.6-19.1); implantation in a small vessel, reference diameter < or = 3.0 mm (OR 6.7, CI 2.4-18.7); and residual stenosis after stent implantation of > 8% (OR 3.1, CI 1.2-8.1).

Aged↗
PubMed1993

Quantitative analysis of elastic recoil after balloon angioplasty and after intracoronary implantation of balloon-expandable Palmaz-Schatz stents.

OBJECTIVES: The purpose of this study was to measure elastic recoil from sequential angiograms after balloon angioplasty and after implantation of a balloon-expandable Palmaz-Schatz stent in the same patient, and to compare the results with the late angiographic outcome. BACKGROUND: The immediate result of coronary balloon angioplasty is influenced by plastic deformation, primarily of the atherosclerotic plaque, and by elastic recoil, primarily of the less or nondiseased vessel circumference. METHODS: The extent of elastic recoil was measured quantitatively as the difference between maximal balloon size and the resulting vessel diameter or cross-sectional area. RESULTS: Analysis was performed in 60 patients who received a single stent for late restenosis after initially successful coronary balloon angioplasty. Minimal lumen diameter (minimal cross-sectional area) was 0.98 +/- 0.43 mm (0.97 +/- 0.67 mm2) before balloon angioplasty, 2.06 +/- 0.36 mm (3.68 +/- 1.17 mm2) after angioplasty (both p < 0.001 vs. values before angioplasty) and 2.98 +/- 0.26 mm (7.12 +/- 1.28 mm2) after stenting (both p < 0.001 vs. postangioplasty results). No significant changes in vessel reference diameters or areas were measured. Mean balloon/artery ratios were similar in both procedures, ranging from 0.93 to 0.96. The calculated mean elastic recoil was 0.98 +/- 0.50 mm in diameter (31%) and 3.67 +/- 2.05 mm2 in area (48%) after balloon angioplasty compared with 0.10 +/- 0.07 mm (3.5%) and 0.38 +/- 0.36 mm2 (5.1%) after stenting. Increasing balloon sizes induced increased vessel stretch, which was followed by increased elastic recoil in the angioplasty group in contrast to the stenting group. Short, noncalcified and eccentric lesions tend to be associated with increased recoil after balloon angioplasty. Overdilation or underdilation in one of the procedures, changes in postprocedural vasomotion or postprocedural thrombus formation was not responsible for this outcome. After 6 months mean minimal lumen diameter was 2.39 +/- 0.58 mm, suggesting a mean hyperplasia of 0.59 +/- 0.51 mm. Twelve patients (20%) had a follow-up diameter that was equal to or less than the mean postangioplasty result and eight patients (14%) had a diameter stenosis of > 50%. CONCLUSIONS: The implantation of a Palmaz-Schatz stent almost completely eliminates the decrease in vessel dimensions caused by elastic recoil and therefore diminishes the impact of hyperplasia and reduces the rate of restenosis.

Adult↗
PubMed1993

Subacute thrombotic complications after intracoronary implantation of Palmaz-Schatz stents.

Despite excellent results as a bail-out procedure for the management of abrupt closure after balloon angioplasty and the potential beneficial effects on restenosis after angioplasty, intracoronary stenting is limited, especially by subacute stent thrombosis. In 100 consecutive patients with intracoronary implantation of 118 Palmaz-Schatz stents, 10 patients (10%) developed subacute stent thrombosis during their hospital course 3 to 9 days after implantation. Therapy included intravenous thrombolysis, mechanical recanalization by balloon angioplasty, and emergency bypass surgery. Although successful recanalization was maintained in eight of nine nonsurgically treated patients within 2 hours after the onset of symptoms, seven patients developed myocardial infarction, with two patients having Q wave myocardial infarction and five patients having non-Q wave myocardial infarction. By univariate analysis, several variables could be identified as risk factors for the development of subacute stent thrombosis: bail-out implantations (odds ratio: 6.42; 95% confidence interval: 1.53 to 26.38; p = 0.007), unstable angina (12.32; 1.50 to 101.37; p = 0.006), long (5.44; 1.31 to 22.65; p = 0.015) and complex (type C) lesions (8.17; 1.93 to 34.50; p = 0.002) with large plaque areas (9.85; 1.96 to 44.51; p = 0.002), symptomatic postangioplasty dissections (4.36; 1.10 to 16.90; p = 0.029), incomplete wrapping of the dissection after stenting (6.50; 1.10 to 42.30; p = 0.039), and vessel irregularities distal to the stented segment (21.70; 4.12 to 113.18; p < 0.001). These variables, except the variable large plaque area, were confirmed as independent predictors of subacute stent thrombosis by a stepwise multivariate logistic regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Revascularization measures after acute myocardial infarct].

Thrombolytic therapy in acute myocardial infarction reduces mortality significantly. This acute effect seems to be counterbalanced by the increased mortality during follow-up whether or not the patient has been treated with thrombolytic therapy. Thrombolysis seems to be a first step in the treatment of acute myocardial infarction. Revascularization procedures are able to improve patient prognosis. Long-term follow-up demonstrated this fact whether or not PTCA was performed in the acute setting or on an elective basis. The 6-year survival was 80%. This survival rate was higher for patients who underwent PTCA than for those who were not undergoing PTCA and those who had no reperfusion of the coronary artery. The best prognosis was found for patients with coronary bypass surgery, indicating that revascularization should be the aim of treatment. The 6-year survival rate was found to be 92% and is thus in the range of patients with coronary artery disease. Acute infarct PTCA is limited to patients with cardiogenic shock and is particularly useful for patients with occlusion of the main stem of the left coronary artery. Acute infarct PTCA is also recommended in patients with contraindications for thrombolytic therapy, when interventions can be performed rapidly, when a large infarct size is present and infarct time is less than 4 hours. Whether or not RESCUE-PTCA should be recommended is under investigation. Patients with an open coronary artery have a better prognosis than patients with occluded coronary arteries, but during the acute stage, spontaneous recanalization is present in many patients. The RESCUE study will address this question. Elective PTCA is recommended as well as coronary bypass surgery, when successful reperfusion is achieved and one-or two-vessel disease is present or there is a two- or three-vessel disease or main stem involvement, respectively. In patients with coronary lesions less than 70% conservative treatment is useful. The guidelines of the American College of Cardiology and the American Heart Association are strongly recommended.

Angioplasty, Balloon, Coronary↗
PubMed1993

[Multicenter results of coronary implantation of balloon expandable Palmaz-Schatz vascular stents].

Intracoronary stenting was designed to handle acute vessel closure after balloon angioplasty and to reduce the rate of restenosis. In three cardiology centers the implantation of 200 balloon-expandable Palmaz-Schatz stents was attempted in 179 patients. The implantation was successful in 170 patients (95%). During bail-out implantation for acute vessel closure or symptomatic dissections after balloon angioplasty, implantation succeeded in 60 (91%) of 66 attempted patients, who recovered immediately from ischemia. Three patients received emergency bypass surgery and three patients were kept on medical therapy. Restenosis after 4 to 6 months, defined as > 50% diameter reduction, was documented angiographically in 18 (15.3%) of 118 presently controlled patients. Patients with single stent implantation (n = 106) presented a late restenosis rate of 10.4% in contrast to patients with multiple stent implantation (n = 12), who presented a restenosis rate of 58.4%. Similar results on restenosis were found for patients with elective and bail-out stent implantation. Acute thrombotic stent occlusion occurred in three patients (1.8%) during the first 24 h after stenting. Three to 9 days after implantation subacute stent thrombosis occurred in 15 (8.8%) of 170 patients. Despite adequate therapy including thrombolysis, balloon angioplasty or emergency bypass surgery in 14 of 15 patients Q-wave myocardial infarction was documented in six patients and non Q-wave myocardial infarction in five patients. The following parameters were identified as risk factors for the development of subacute stent thrombosis: bail-out indication, unstable angina, type C lesion, stenosis length > 1.5 cm, plaque area > 3.5 mm2, symptomatic dissection after balloon angioplasty, incomplete wrapping of the dissection after stenting and residual distal vessel irregularities after stenting. Bleeding complications occurred in 12.4% of the patients and were related to the anticoagulation and antiaggregation therapy. In conclusion, the implantation of Palmaz-Schatz stents is an excellent bail-out device to treat acute vessel closure or symptomatic dissections after angioplasty. Elective and bail-out single stent implantation is associated with a reduced rate of restenosis when compared to conventional balloon angioplasty. At present, subacute stent thrombosis and bleeding complications are the major limitations with a combined rate of 15.9%.

Adult↗
PubMed1992

[Coronary vascular stent implantation--experiences with the first 100 implants].

Coronary stent implantation was performed for blocking elastin recoil, reducing acute complications and restenosis. In 89 (95%) of 91 patients successful stent implantation was possible. No stent embolization occurred. Coronary luminal diameter measured 1.05 +/- 0.57 before PTCA and 1.9 +/- 0.2 mm post PTCA. After stent implantation mean diameter of the coronary artery measured 3.05 +/- 0.2 mm, with a balloon diameter of 3.0. Thus, elastic recoil is nearly completely blocked. In 28 (31%) of 91 patients stent implantation was performed for acute symptomatic dissection in 27 patients and occlusion in one patient. Stent delivery was successful in all. There was no acute occlusion, one acute thrombosis which could be treated with urokinase, no Q-wave-infarct, 4 (14%) non-Q-wave-infarcts and 14 (20%) CK-elevations without ECG changes. Coronary bypass surgery was necessary in 2 patients on an elective base during follow-up. In 72 (90%) of 80 patients follow-up coronary angiograms after 4 to 6 months were performed. Restenosis rate measured 21% overall, 14% for single stent, 60% for multiple stent implantation, and 14% in bail-out situations. Subacute thrombosis occurred in 10 (12%) of 89 patients, 7 (70%) of 10 events after bail-out stenting. Recanalization by thrombolytic and/or PTCA was possible in 9/10 patients. By improving monitoring of anticoagulation, the subacute thrombosis rate could be reduced to 3% even in bail-out situations. Bleeding complication occurred in 10% of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Lyme borreliosis in an endemic region in Europe. Prevalence of antibodies and clinical spectrum].

A representative sample of the population of two villages located in an area of North Baden where borreliosis is endemic was studied to ascertain the prevalence of antibodies against Borrelia burgdorferi and of clinical abnormalities. The aim of the study was to determine what clinical symptoms and signs were correlated with positive antibody status. Out of the 2928 inhabitants 1228 were investigated, and 207 of these (16.9%) were seropositive. Certain clinical abnormalities showed highly significant statistical correlations with positive antibody status. Arthritis (defined in terms of heat, redness and effusion) was noted in 34.3% of the seropositive patients, but in only 9.3% of seronegative patients (P less than 0.0001). Complaints of arthralgia were noted in 23.4% of seropositive patients and 13.3% of seronegative patients (P less than 0.001). Motor neuropathies showed similar correlation with seropositive status (12.0% vs 4.0%; P less than 0.001), as did sensory neuropathies (25.4% vs 6.7%; P less than 0.001). Differences were also noted in the prevalence of cardiac arrhythmias (ventricular extrasystoles, conduction abnormalities and intermittent tachyarrhythmias), which were found in 19.8% of the seropositive as against 3.0% of the seronegative subjects (P less than 0.001). The findings are evidence of a causal link between the listed clinical abnormalities and the presence of antibodies against Borrelia burgdorferi.

Adolescent↗