[Percutaneous approaches for mitral valve interventions--a real alternative technique for standard cardiac surgery?]. / Die perkutane Mitralklappenintervention bei Mitralklappeninsuffizienz--eine Alternative zur konventionellen Herzchirurgie?

Standard therapy of advanced mitral valve regurgitation currently consists of mitral valve reconstruction through heart surgery including heart-lung machine employment. Typically, a ring is implanted and a leaflet reduced, if necessary, to approximate the posterior and anterior mitral valve leaflets to each other. Because of high comorbidity among this patient population, new and less burdening catheter-based techniques have been developed. Clinical etiology of mitral valve regurgitation is divided into two categories: "structural" versus "functional". The MONARC system of the Edwards Lifesciences company consists of three components--distal stent, bridge with bioabsorbing coating, proximal stent--and is implanted into the coronary sinus. The underlying principle is an indirect annuloplasty of the mitral valve annulus resulting from resorption of the bridge coating and leading to a reduction and indirect tightening of the mitral valve annulus. The EVOLUTION I (EV I) study in patients suffering from functional mitral regurgitation to a degree between 2+ and 4+ revealed--12 months after the MONARC implantation--a mitral valve regurgitation reduction from 2.48 to 1.78. The EV I study found interaction of the foreshortening bridge with the coronary arteries in some patients. This problem is most widely excluded by previous computed tomographic or angiographic examinations in the ongoing follow-up study EV II. Direct annuloplasty is made possible in case of functional mitral regurgitation by using the Mitralign Percutaneous Annuloplasty System (MPAS) of the Mitralign company. In doing so, an improved coadaptation of the mitral valve leaflet is achieved by inserting three sutures into the posterior mitral valve annulus and subsequent plicating.The MitraClip of the Evalve company uses the principle of the edge-to-edge technique. In doing so, the posterior and anterior leaflets are joined by implanting a clip, resulting in a reduction of mitral regurgitation with two diastolic orifices. In contrast to strukthe other two procedures, the MitraClip can be used for both functional and structural mitral valve regurgitation. The EVEREST I study and the EVEREST II study, as far as it has already been published, show that this procedure is secure and its results are very positive. The previous results of all three procedures show that catheter-based techniques for treating high-risk patients suffering from mitral valve regurgitation arrive at positive results in part, so that possibly a real alternative to conventional heart surgery will be available in the future.

Percutaneous endocardial injection of erythropoietin: assessment of cardioprotection by electromechanical mapping.

BACKGROUND: Apart from its well-known stimulation of erythropoiesis, erythropoietin (EPO) exhibits angiogenic and anti-apoptotic effects. These cellular protective effects have also been described in experimental acute myocardial infarction models. We investigated the effects of EPO in a porcine model of chronic progressive myocardial ischaemia. METHODS: At weeks 2 and 6 after implantation of a circumflex ameroid constrictor, endocardial electromechanical NOGA system (Biosense Webster, Inc., California, USA) mapping of the left ventricle, coronary and ventricular angiography, as well as echocardiography were performed. Two weeks after ameroid placement, 13 pigs were randomized with 7 pigs receiving 10.000 U EPO and 6 pigs receiving placebo into the ischaemic region using a NOGA guided percutaneous transendocardial injection catheter, MYOSTAR. After 6 weeks, histology (Masson's Trichrome) was analyzed. RESULTS: Endocardial electromechanical mapping showed an increase of mean unipolar voltage (UV) amplitude in the ischaemic myocardial segments in the EPO-treated animals (8.5 mV pre and 10.6 mV post treatment) and a significantly reduced ischaemic surface area compared to the control group (19% vs. 41%) suggesting a decline in ischaemic injury. Echocardiography revealed 2,2 hypokinetic segments of the lateral wall in the EPO group vs. 3,3 in the control groups. The mean ejection fraction was 64% in the EPO group and 55% in the placebo group. Quantitative histological analysis of the ischaemic regions revealed a reduction of myocardial fibrosis (8% vs. 28%) in the EPO group. CONCLUSION: Endocardial EPO injection may induce cardioprotective effects in hibernating myocardium and may attenuate the progression of ischaemic tissue damage.

Tissue velocity imaging during dobutamine stimulation for assessment of myocardial viability: segmental analysis in patients after myocardial infarction.

BACKGROUND: Dobutamine stress echocardiography (DSE) is an established method for the detection of viable myocardium, but evaluation of this method is subjective. Tissue velocity Imaging (TVI) allows quantitative analysis of regional myocardial wall motion by assessment of systolic myocardial velocities. The aim of this study was to evaluate the diagnostic value of DSE and TVI for detection of viable myocardium. METHODS: In 56 patients (58+/-12 years) with previous myocardial infarction (130+/-42 days, mean ejection fraction 42+/-15%) low-dose DSE was combined with analysis of peak systolic myocardial velocities (Vpeak) by TVI for assessment of myocardial viability. As reference served a follow-up echocardiography after successful revascularization (mean 91+/-3 days). RESULTS: Of a total of 896 segments 200 showed abnormal wall motion (31 mildly hypokinetic, 50 severely hypokinetic, 115 akinetic, 4 dyskinetic). In 125 of these 200 segments regional improvement of regional wall motion was observed (62.5% viable). An increase of Vpeak>1 cm/s during dobutamine stimulation allowed the identification of viable myocardium with a sensitivity of 82% and a specificity 82% (DSE: 77% and 80%). By receiver operating characteristic (ROC) curve analysis, a cut-off value of 1.0 cm/s was the best parameter to differ viable from nonviable myocardium (area under the curve 0.85; p<0.01; 95% CI 0.79 to 0.90). Improvement of global ejection fraction after revascularization (47+/-13%, p=0.11) corresponded with three TVI viable segments with a sensitivity of 92% and a specificity of 89% (p=0.012). CONCLUSIONS: TVI allows the identification of viable myocardium during dobutamine stimulation and enables a quantitative interpretation of DSE.