Rainer Zotz

Rapid in vitro biocompatibility assay of endovascular stents by flow cytometry using platelet activation and platelet-leukocyte aggregation.

Clinical studies suggest that stent design and surface texture are responsible for differences in biocompatibility of metallic endovascular stents. A simple in vitro experimental setup was established to test stent-induced degree of platelet and leukocyte activation and platelet-leukocyte aggregation by flow cytometry. Heparin-coated tantalum stents and gold-coated and uncoated stainless steel stents were tested. Stents were implanted into silicone tubes and exposed to blood from healthy volunteers. Platelet and leukocyte activation and percentage of leukocyte-platelet aggregates were determined in a whole-blood assay by subsequent staining for activation-associated antigens (CD41a, CD42b, CD62p, and fibrinogen binding) and leukocyte antigens (CD14 and CD45) and flow cytometric analysis. Blood taken directly after venous puncture or exposed to the silicone tube alone was used as negative controls. Positive control was in vitro stimulation with thrombin receptor activating peptide (TRAP-6). Low degree of platelet activation and significant increase in monocyte- and neutrophil-platelet aggregation were observed in blood exposed to stents (P < 0.05). In addition, leukocyte activation was induced as measured by increased CD45 and CD14 expression. Heparin coated stents continuously induced less platelet activation and leukocyte-platelet aggregation than uncoated stainless steel stents of the same length and shorter stents of the same structure. Stent surface coating and texture plays a role in platelet and leukocyte activation and leukocyte-platelet aggregation. Using this simple in vitro assay and whole blood and flow cytometry, it seems possible to differentiate stents by their potency to activate platelets and/or leukocytes. This assay could be applied for improving the biocompatibility of coronary stents.

Noncommunicating Intramural Hematoma: An Indication of Developing Aortic Dissection?

A 60-year-old patient was referred to the hospital for persisting chest pain. The first transesophageal echocardiogram showed localized hematomas without aortic dissection. Several days later the patient suffered complete paraplegia after a second episode of chest pain. The transesophageal echocardiogram now showed a complete aortic dissection. Thus whether intramural hematomas can be regarded as an early sign of impending aortic dissection needs to be investigated.

Pre-procedural expression of Mac-1 and LFA-1 on leukocytes for prediction of late restenosis and their possible correlation with advanced coronary artery disease.

The activation status of the inflammatory system has been suggested to play an important role in predicting restenosis. Activation of leukocyte adhesion molecules occur after coronary intervention and the level of activation correlates to restenosis. However, little is known about the specific role of adhesion molecules before intervention. The purpose of this study concerned the search for differences in the expression level of selected adhesion molecules to identify suitable tools for the pre‐procedural identification of restenosis patients prior to angioplasty.

Fragment Reconstruction of Coronary Arteries by Transesophageal Echocardiography

Background— If transesophageal echocardiography (TEE) is to play a role in coronary diagnostics, satisfactory image documentation of the coronary status is indispensable so that the requirements for validity and quality assurance of a medical examination can be met. Our goal was to develop a suitable and valid procedure for imaging coronary arteries with 2D TEE. Methods and Resultsmdash; After pilot trials and formulation of requirements, a new method of imaging coronary arteries was designed, supported by theoretical and mathematical principles: FRC-TEE, or fragment reconstruction of coronary arteries by means of 2D TEE. The method generates images of successive vessel fragments so that reconstruction in a summation picture is possible. The procedure orients itself to the vessel and ensures proof of identity by permanently following it on the screen. FRC-TEE was evaluated in 12 consecutive patients with an indication for TEE. One hundred percent visualization in proximal, middle, and distal segments was ...

Changes of neurohumoral parameters and endothelin-1 in response to exercise in patients with mild to moderate congestive heart failure

UNLABELLED Plasma endothelin levels are increased in patients with moderate and severe CHF. Conflicting data exist about the endothelin-1 (ET) level in patients with mild to moderate CHF and the effect of maximal exercise on plasma ET levels. METHODS AND RESULTS We determined the plasma levels of ET and various neurohumoral parameters in 93 patients with CHF in functional class II and III of the NYHA classification at rest and after maximal bicycle exercise. Baseline ET level was increased compared to an age-matched healthy volunteer group (6.95+/-0.31 vs 3.29+/-0.17 pg/ml, mean+/-S.E.M., P<0.05), without significant differences between NYHA class II and III patients. Maximal exercise did not increase the ET level. In contrast, the neurohumoral parameters were significantly increased with maximal exercise. In conclusion, plasma levels of ET are increased in patients with mild to moderate CHF. However, no further increase in response to exercise was observed. Thus, it is highly unlikely that exercise capacity may be limited by ET-mediated peripheral vasoconstriction.

Transthoracic and transesophageal echocardiography to diagnose ventricular septal rupture: importance of right heart infarction.

Background:Rapid and accurate diagnosis of ventricular septal rupture (VSR) remains difficult, and the monitoring of hemodynamic deterioration is a prerequisite for the institution of adequate therapy. The timing of surgical repair is a matter of controversy. Methods:Transthoracic, transesophageal, color Doppler, and contrast echocardiography were evaluated in 17 patients with VSR in whom the diagnosis was confirmed by catheterization, surgery, or necropsy. Results:Routine transthoracic echocardiography visualized VSR in four out of 17 patients and, with additional views, in 12 out of 17 patients. Color Doppler echocardiography identified the rupture in 15 out of 16, and contrast echocardiography in 11 out of 11 patients. VSR was identified using transesophageal echocardiography in six out of nine patients, and using color Doppler and contrast echocardiography in all patients. Eight out of 10 patients who developed right heart myocardial infarction (RMI) died, whereas all patients without RMI survived (P= 0.0070). Similarly, eight out of 10 patients with shock died, whereas all patients without survived (P= 0.0070). Shock occurred more often in patients with RMI (eight out of 10) than in patients without (two out of six). All patients with both RMI and shock died, whereas those without both conditions survived (P= 0.0002). Conclusion:Modern echocardiography is the method of choice in the diagnosis of VSR. Right ventricular function should be evaluated in patients with VSR because patients with RMI are at high risk of hemodynamic deterioration, with poor outcome. RMI, visible as abnormal wall motion, was identified better with transesophageal than with transthoracic echocardiography.

Atypical Bland‐White‐Garland Syndrome: A 58‐Year‐Old Woman with Stenosis of the Pulmonary Origin of the Left Coronary Artery

The anomalous origin of the left coronary artery from the main pulmonary trunk (also known as Bland‐White‐Garland syndrome) is a rare congenital malformation that occurs in 0.4% of patients with cardiac anomalies. We present an adult case (a 58‐year‐old woman) of atypical Bland‐White‐Garland syndrome. The patient displayed a stenosis at the ostium of the anomalous origin of the left coronary artery and an aortopulmonary fistula. Using conventional angiography, it was not possible to differentiate between an anomalous origin of the pulmonary coronary artery and total stenosis of the left main coronary artery in combination with a pulmonary fistula. However, transesophageal echocardiography (TEE) succeeded in making this differential diagnosis. Conclusion: If there is subtotal or total occlusion, TEE can be used for detection of coronary vessel morphology, particularly in cases of coronary anomalies.

Left ventricular contrast echocardiography — echoventriculography

Echographic contrast agents were first used for structure identification [1, 2]. Pooled data analysis revealed a high safety [3]. Special agents have been developed in order to standardize right heart opacification [4] and to enhance echocardiographic Doppler signals [5–9]. The latter effect was not expected [9]. All agents contain air as reported by others between 12 and 35 µl/ml [9]. The stability reaches more than 5 min. Injections of up to 20 ml are necessary. The osmolality is between 345 and 1740 mosm/kg H2O [9].

Fragment reconstruction of coronary arteries using transesophageal echocardiography for coronary diagnostics

AIMS Ultrasound differs procedurally from the established methods for non-invasive coronary visualization and is therefore an interesting alternative for non-invasive diagnostics. In this study, fragment reconstruction of coronary arteries by transesophageal echocardiography (FRC-TEE) was investigated for the first time in a patient population being evaluated for coronary angiography. METHODS AND RESULTS Ultrasonic and angiographic findings were compared visually and using quantitative measurements in 50 patients. One hundred and seventy-one vessels were examined by FRC-TEE. The total lengths visualized were 9.6 +/- 1.7 cm for the right coronary artery, 7.0 +/- 1.1 cm for left circumflex, 3.9 +/- 1.2 cm for left anterior descending (LAD), and 1.5 +/- 0.8 cm for the left main coronary artery. There was high concordance between results of both procedures. Sixty-three stenoses were detected using FRC-TEE. The mean difference in degree of stenosis between techniques was 0.2 +/- 5.1%. Stents could be visualized in 19 segments. FRC-TEE detected distal stenoses of the coronary arteries to only a limited extent: 14 stenoses and 2 stents, predominantly in the LAD artery (n = 13), were not identified. CONCLUSIONS FRC-TEE is a potential method for diagnosing coronary artery disease. FRC-TEE and angiography yield comparable findings during the evaluation of coronary lesions. Further investigations are needed to verify the encouraging findings and define FRC-TEEs applications.

Ermittlung von Koronargefäßverläufen in 3D-Kontrastechokardiogrammen

Im vorliegenden Artikel wird ein Volumerenderingverfahren vorgestellt, das fur Visualisierung von stark gerichteten, rohrenformigen Strukturen konzipert ist. In einem Analyseschritt wird mit Hilfe von Strukturtensoren fur jedes Voxel des Volumens ein Mas fur Koharenz (Ahnlichkeit mit einer Rohre) ermittelt. In Abhangigkeit dieses Mases wird der Transparenzwert der Voxel gesetzt. Das Visualisierungsverfahren wird fur die Darstellung der Verlaufe von Koronarien in 3D-Kontrastechokardiogrammen verwendet.