Zeitschrift für Kardiologie

This paper describes our research into the vascular mechanics of the coronary artery and plaque. The three sections describe the determination of arterial mechanical properties using intravascular ultrasound (IVUS), a constitutive relation for the arterial wall, and finite element method (FEM) models of the arterial wall and atheroma. Methods: Inflation testing of porcine left anterior descending coronary arteries was conducted. The changes in the vessel geometry were monitored using IVUS, and intracoronary pressure was recorded using a pressure transducer. The creep and quasistatic stress/strain responses were determined. A Standard Linear Solid (SLS) was modified to reproduce the non-linear elastic behavior of the arterial wall. This Standard Non-linear Solid (SNS) was implemented into an axisymetric thick-walled cylinder numerical model. Finite element analysis models were created for five age groups and four levels of stenosis using the Pathobiological Determinants of Atherosclerosis Youth (PDAY) database. Results: The arteris exhibited non-linear elastic behavior. The total tissue creep strain was ɛcreep = 0.082±0.018 mm/mm. The numerical model could reproduce both the non-linearity of the porcine data and time dependent behavior of the arterial wall found in the literature with a correlation coefficient of 0.985. Increasing age had a strong positive correlation with the shoulder stress level, (r = 0.95). The 30% stenosis had the highest shoulder stress due to the combination of a fully formed lipid pool and a thin cap. Conclusions: Studying the solid mechanics of the arterial wall and the atheroma provide important insights into the mechanisms involved in plaque rupture.

In einer Pilotstudie mit insgesamt 43 Patienten (31 Männer, 12 Frauen) mit einem mittleren Alter von 64,2±12,1 Jahren wurde die Wirksamkeit einer kombinierten Therapie mit Alteplase in einer Dosis von 50mg (15mg Bolus, 35mg als Erhaltungsinfusion über 60 Minuten) und Tirofiban in einer Dosierung von 0,4 μg/kg/min über eine 1/2h als Startinfusion und einer Erhaltungsinfusion von 0,10μg/kg/min über 24h (modifiziert nach PRISM-PLUS) bei vier Patienten und in einer Dosierung von 10μg/kg als Bolus über 3min und einer Erhaltungsinfusion von 0,15μg/kg/min (modifiziert nach RESTORE) bei 39 Patienten beim akuten Myokardinfarkt hinsichtlich primärer Offenheit des Infarktgefäßes, TIMI Fluss bei Koronarangiographie nach 60h, 30-Tage-Mortalität und Blutungskomplikationen überprüft. Die Tirofibandosierung nach PRISM-PLUS-Studie erbrachte eine primäre Offenheit des Infarktgefäßes von 25% mit TIMI-III-Fluss in einem Fall. Komplikationen in den ersten 30 Tagen traten nicht auf.    Bei Tirofibandosierung nach RESTORE-Studie lag die primäre Offenheitsrate bei 87% mit TIMI-III-Fluss in 79% der Fälle. Die 30-Tage-Mortalität betrug 2,6%; eine leichte Nachblutung nach PTCA trat auf.    Die Kombination von dosisreduzierter Alteplase und Tirofiban mit Bolus und Erhaltungsinfusion über 24h erscheint bei guter Wirksamkeit und niedriger Komplikationsrate geeignet, in der Therapie des akuten Myokardinfarktes eingesetzt zu werden.

From 1991 to 1993, our group carried out extensive studies in the development of a new catheter-interventional concept of treatment for HOCM and suggested in 1994 the injection of absolute ethanol into the first major septal branch using the common PTCA technique. This approach was first used therapeutically by Sigwart in London and by our group in Bielefeld. Based on rhythmologic studies of other authors we suggested the designation Transcoronary Ablation of Septal Hypertrophy (TASH). Since 1995, an estimated 1000 patients (about 600 from Germany) in some 20 countries have been treated by this method. In 1997 a national multicenter TASH-registry was created by the German Cardiac Society.¶   During the last five years extensive studies have been performed by different groups. Significant clinical and hemodynamic improvements were consistently found. This was true for both young and old patients, for patients with resting gradient and with provocable gradient. Clinical improvement (rate of improved patients about 90%) was seen under conditions of rest and stress, as well as during long-term follow-up. Specifically, there was a significant decrease of functional class, a reduced rate of syncope, and a reduced degree of mitral insufficiency. Exercise capacity, oxygen uptake and the cardiac index increased, intraventricular gradient, the enddiastolic pressure of the left ventricle and the left atrial size decreased. Also there was a decrease in the septal thickness with increase in the cross sectional area of the outflow tract and with local contraction disorder. PET examination showed an ablation induced local myocardial defect. There was also evidence for improved diastolic function. Electrophysiological and Holter monitor studies indicated no increased arrhythmogenicity. The prognosis seems to be improved. Histologically, an atypical infarct pattern was found, i.e., the common roundcell infiltration and the fibrotic process were surrounding but not penetrating the alcohol induced myocardial center of necrosis. The in-hospital mortality rate amounts to about 1.8%. The rate of permanent total av-block after TASH is less than 10%. In 15% a second TASH is necessary.¶   In summary, during the last five years TASH has become a promising new catheter interventional therapy for HOCM, which compares favorably with surgical treatment. In experienced centers it has become a routinely performed procedure. The indication should be limited to severely symptomatic patients with typical (subaortic) HOCM. Further careful clinical examinations after TASH are required. All patients should be enrolled into a registry. TASH also constitutes a new area for comprehensive clinical research.

Das Marfan-Syndrom ist eine erbliche Bindegewebserkrankung, die mit einer erhöhten Inzidenz von kardiovaskulären Komplikationen verbunden ist. Wir beschreiben unsere Erfahrungen bei der chirurgischen Behandlung von 243 Patienten mit Marfan-Syndrom. Bezüglich der Behandlung der anuloaortalen Ektasie zeigen wir unsere Ergebnisse bei der Verwendung der klassischen Operationsmethoden nach BentallDeBono und Cabrol. Neure Operationsmethoden wie die Verfahren nach David und Yacoub werden kritisch gewertet und eine eigene Modifikation zum Klappen erhaltenden Ersatz der Aorta ascendens wird vorgestellt. Bei einer großen Zahl von Patienten waren Operationen wegen der Manifestetion des Marfan-Syndroms im Bereich der distal der Aorta ascendens gelegenen Aortensegmente, der Mitralklappe und der Trikuspidalklappe erforderlich. Die Indikation zur Rekonstruktion bzw. zum Ersatz der Mitralklappe wird weitgehend entsprechend den klassischen Kriterien gestellt. Die Langzeitresultate des Erhalts der nativen Aortenklappe sowie der Mitralklappenrekonstruktion sind noch nicht vorhanden.

Objectives. The objectives of this review article are to provide detailed physicochemical information on the nature of pathological cardiovascular deposits, PCD, isolated from different sites of the human cardiovascular system. In order to help to understand the complex mechanism of the formation of PCD, special emphasis is focused on the attempt to recognize early precursor(s) of PCD by utilizing combined in vivo and in vitro studies. Background. The common idea is that PCD is hydroxyapatite (HAP), Ca5(PO4)3OH; however, this is questionable and deserves critical evaluation. Methods. After isolation of PCD, deproteination followed, producing pure inorganic fraction of deposits that were subject to chemical analyses, x-ray diffraction (XRD), FT-IR spectroscopy, optical, scanning electron microscopy (SEM), polarizing microscopy, energy dispersive x-ray microanalyses (EDS) and thermodynamic solubility measurements. The same methods were used to characterize the in vitro and in vivo formed calcific deposits. Results. The results of chemical analyses provided essential information that PCD contained significant organic fraction; inorganic fraction appears to be bioapatite, corresponding to defect HAP with substantial macro incorporation of sodium, magnesium, carbonate and fluoride. Structural XRD data show apatitic pattern; however, variable crystallinity of PCD suggests that crystallization is a time and flow dynamics-dependent process. Critical thermodynamic solubility measurements unequivocally prove that PCD are significantly more soluble than HAP. Conclusions. The PCDs are morphologically and chemically heterogeneous products which may be a consequence of time- dependent hydrolytic transformation of precursors that may include amorphous calcium phosphate and octacalcium phosphate (OCP) Ca4H(PO4)3.

Intravascular sonotherapy has been introduced as a potential alternative to brachytherapy for prophylactic and therapeutic application in patients after coronary stent placement. Sonotherapy represents a non-ablative, non-thermal form of therapeutic ultrasound. The ultrasound catheter with diameter between 4 and 5 French carries up to 6 electronic elements operating currently at a frequency of 1.0 to 1.4 MHz. Animal studies have proven the efficacy of intravascular sonotherapy with respect to a reduction of neointimal ingrowth after stent placement. A first multicenter observational study in humans has documented that its application is safe and yields favorable results after coronary stenting, also in complex patient and lesion characteristics. This technique is currently under investigation in large prospective, multicenter, randomized studies performed in patients with de novo stenting or documented in-stent restenosis.

Written informed consent for pacemaker and ICD patients should be easy to understand and provided in written form in the patient’s language. Comprehensiveness is required. It is essential to address driving and running machines, complication rates, benefits in appropriate hierarchical order and future necessary interventions. Eventually potential risks, e.g., flying, sports, sexual activity should be mentioned. It is important to explain pacemaker systems and ICD devices in details including cardiac resynchronization therapy (CRT) for heart failure. One of the main aspects concerns protection of human subjects participating in clinical studies. Informed consent necessitates a statement that the study involves research. This statement should include explanation of the purposes of the study, expected duration, description of the procedures, identification of experimental procedures, description of foreseeable risks or discomforts, and disclosure of alternative procedures. Further information should be given on psychological concerns, sexual activity, driving and quality of life in pacemaker and ICD patients.

Ungeachtet der Schwierigkeiten bei der Bestätigung einer paradoxen Embolie konnte der Zusammenhang zwischen dem Vorliegen eines ventiloffenen Foramen ovale (PFO) und zerebraler Ischämie-Ereignisse unklarer Ursache wiederholt nachgewiesen werden. Darüber hinaus wurde berichtet, daß das Risiko von Embolie-Rezidiven bei diesen Patienten 3–4% pro Jahr beträgt. Eine zuverlässige Risikostratifikation der Patienten mit PFO auf der Basis klinischer oder echokardiographischer Befunde ist bisher – mit Ausnahme der hämodynamisch wirksamen Lungenembolie – in der Regel nicht möglich. Das Vorliegen eines Vorhofseptumaneurysmas und eine weite Öffnung des PFO während des Herzzyklus oder ein großer interatrialer Shunt bei der transösophagealen Kontrast-Echokardiographie werden jedoch von manchen Autoren als Risikofaktoren angesehen. Die sekundäre Prävention paradoxer Embolien mittels oraler Antikoagulanzen (Warfarin) beinhaltet das Risiko einer signifikanten Blutung (Inzidenzrate 2–5% pro Jahr) und mangelhaften Compliance der Patienten. Außerdem scheint diese Therapieform wenig effektiv zu sein. Der chirurgische Verschluß des PFO ist ein technisch ausgereifter, sicherer Eingriff. Erste Berichte bestätigen seine hohe Effektivität hinsichtlich der Rezidivprophylaxe, weitere prospektive Studien sind jedoch erforderlich, um die für eine chirurgische Behandlung geeigneten Patienten festzulegen. Kathetertechnische Verfahren zum PFO-Verschluß stehen ebenfalls zur Verfügung und befinden sich derzeit in der Phase der klinischen Erprobung. Weitere technische Verbesserungen erscheinen jedoch erforderlich, um den Ablauf des interventionellen Eingriffes zu vereinfachen, die Stabilität dieser Systeme zu erhöhen und die Komplikationsgefahr zu minimieren.