Drug-eluting stents for the treatment of pulmonary vein stenosis after atrial fibrillation ablation.

AIMS: Pulmonary vein (PV) stenosis (PVS) is a complication of radiofrequency PV isolation (PVI). Reported restenosis rates after balloon dilatation and bare-metal stent implantation are high. Drug-eluting stent implantation (DES) has not been reported in the setting of PVS. METHODS AND RESULTS: Patients suspected of having PVS after PVI based on clinical symptoms and transesophageal echocardiography (TEE) follow-up (FU) were referred for PV DES. One or more branches of the affected PV as documented by angiography were stented (paclitaxel or zotarolimus DES). Follow-up consisted of repeat PV angiography and TEE. Over a period of 2 years, five patients were treated with a total of eight DES. A paclitaxel DES was used in seven of eight implants. Mean FU was 12 ± 14 months during which all patients remained asymptomatic. Transesophageal echocardiography Doppler maximal flow velocity (V(max)) of the affected PVs rose from 58 ± 6 cm/s pre-PVI to 207 ± 20 cm/s pre-DES (+358%, P < 0.0001). After DES, V(max) decreased acutely with 86 ± 15 cm/s (-58%, P < 0.01). During FU, V(max) remained stable in three patients and increased moderately in one. Angiography at 3 months confirmed absence of restenosis in the first three patients and moderate (40%) restenosis in one patient. In one patient, an increase of V(max) back to pre-DES values correlated with a 65% peri-stent stenosis, treated with a redo DES. In total, after seven primary DES only one (asymptomatic) proximal margin restenosis required re-stenting. CONCLUSION: Initial experience with DES for PV stenosis suggests an excellent stent patency rate. Transesophageal echocardiography Doppler measurements provide a viable way of monitoring stent patency.

Regional diastolic and systolic function by strain rate imaging for the detection of intramural viability during dobutamine stress echocardiography in a porcine model of myocardial infarction.

The aim of this study was to evaluate diastolic and systolic strain rate measurements for differentiation of transmural/nontransmural infarction during dobutamine stress echocardiography (DSE). An ameroid constrictor was placed around the circumflex artery in 23 pigs inducing chronic vessel occlusion. Five pigs without constrictor served as controls. During high-dose DSE systolic strain rates (SR(sys)), systolic and postsystolic strain values (epsilon(sys), epsilon(ps)) and early and late diastolic strain rates (SR(E) and SR(A)) were determined. At week 6, animals were evaluated regarding myocardial fibrosis. Histology revealed nontransmural in 14 and transmural infarction in 9 animals. In controls, dobutamine induced a linear increase of SR(sys) to 12.3 + or - 0.4 s(-1) at 40 microg/kg per minute (P = 0.001) and a linear decrease of SR(E) to -6.6 + or - 0.3 s(-1) (P = 0.001). In the nontransmural group, SR(sys), epsilon(sys), epsilon(ps) at rest, and during DSE were higher and SR(E) was lower than in the transmural infarction group (P = 0.01). Best predictors for viability were SR(sys) (ROC 0.96, P = 0.0003), SR(E) at 10 microg/kg per minute dobutamine stimulation (ROC 0.94, P = 0.001) and positive SR values during isovolumetric relaxation at 40 microg/kg per minute dobutamine (ROC 0.86, P = 0.004). The extension of fibrosis correlated with SR(sys) at rest, epsilon(sys) at rest, and SR(E) at rest (P < 0.001). For the detection of viability similar diagnostic accuracies of SR(E) and SRsys were seen (sensitivity 93%/93%, specificity 96%/94%, respectively). Diastolic SR analysis seems to be equipotent for the identification of viable myocardium in comparison to systolic SR parameters and allows the differentiation of nontransmural from transmural myocardial infarction with high diagnostic accuracy. (Echocardiography 2010;27:552-562).

[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.

Transplantation of bone marrow-derived stem cells improves myocardial diastolic function: strain rate imaging in a model of hibernating myocardium.

BACKGROUND: The aim of this study was to evaluate the cardioprotective effects of bone marrow-derived stem cells on myocardial compliance in a chronic ischemia model regarding strain rate (SR) parameters during dobutamine stress echocardiography (DSE). METHODS: Ameroid constrictors were placed around the circumflex arteries of 23 domestic pigs to induce chronic vessel occlusions. Fifteen pigs received transendocardially bone marrow derived stem cells, and 8 received placebo injections (a 0.9% solution of NaCl) into the ischemic region. At week 6, the animals were evaluated regarding myocardial fibrosis, neovascularization, apoptosis, and diastolic function during DSE. RESULTS: Stem cell-injected hearts showed significantly less fibrosis, higher ejection fractions, significant neovascularization, and less ventricular dilatation than controls (P < .05). Strain rate imaging revealed improved diastolic function, with higher early diastolic SR values and lower E/Ea ratios compared with controls (P < .05). Early diastolic SR during DSE identifies viable myocardium (extent of fibrosis, r = 0.86, P = .0001). CONCLUSION: The endocardial injection of stem cells improves diastolic function in chronic ischemic myocardium and helps attenuate postinfarction remodeling.

A prospective study on ultrasound-guided percutaneous thrombin injection for treatment of iatrogenic post-catheterisation femoral pseudoaneurysms.

BACKGROUND: The purpose of this study was to evaluate prospectively the safety and efficacy of bovine thrombin injection for the treatment of iatrogenic post-catheterisation pseudoaneurysms. METHODS AND RESULTS: A total of 274 patients (90 women, 184 men, 69.8+/-7 years) with iatrogenic femoral pseudoaneurysms were treated by ultrasound-guided thrombin injection (UGTI). The deepest pseudoaneurysm chamber was entered with a 0.90x40 mm or 90 mm needle and bovine thrombin (solution of 1000 U/ml) was injected. Pseudoaneurysms were associated with diagnostic cardiac catheterisation, percutaneous coronary intervention or invasive electrophysiologic investigation. The majority of the patients were under antiplatelet therapy with aspirin or clopidogrel or both, and additional low dose heparin therapy. A total of 52 patients were treated with either phenprocoumon or enoxaparine body weight adjusted. UGTI was primary successful in 267 of 274 patients (97%). In 3 of 7 patients with a remaining pseudoaneurysm a second injection was required. Three patients were treated by ultrasound-guided compression. One patient was treated by surgical repair of the pseudoaneurysm 1 day after UGTI because a further pseudoaneurysm developed under phenprocoumon therapy. UGTI-related complications such as significant arterial thrombotic events or allergic reactions did not occur. 75 patients (27%) were evaluated by an additional sonography after 3 months to assess the long-term effect. CONCLUSION: UGTI was well tolerated, safe and primarily effective in 97% of patients with iatrogenic femoral pseudoaneurysms. Anticoagulant use did not hinder successful thrombosis. UGTI should be considered as first-line therapy for the treatment of post-catheterisation pseudoaneurysms.

Intramyocardial transplantation of bone marrow-derived stem cells: ultrasonic strain rate imaging in a model of hibernating myocardium.

BACKGROUND: The aim of this study was to evaluate potential cardioprotective effects of bone marrow-derived stem cells in chronic ischemic myocardium regarding strain rate parameters during dobutamine stress echocardiography. METHODS: An ameroid constrictor was placed around the circumflex artery in 23 pigs to induce hibernating myocardium. Pigs received autologous mesenchymal stem cells (auto MSCs), allogeneic MSC (allo MSC), autologous mononuclear cells (auto MNCs), or placebo injections into the ischemic region. During dobutamine stress echocardiography, peak systolic strain rates (SR(sys)) and systolic and postsystolic strain values (epsilon(sys), epsilon(ps)) were determined. The animals were evaluated regarding myocardial fibrosis, neovascularization, apoptosis, and myocardial beta-adrenergic receptor density. RESULTS: The median ejection fraction was reduced in the control group compared with the auto MSC-, allo MSC-, and auto MNC-treated pigs (36.5% vs 46.0% vs 46.0% vs 41.5%; P = .001, respectively). Histopathology revealed a decreased myocardial fibrosis in auto MSC- (16.3%), allo MSC- (11.3%), and auto MNC- (16.7%) treated pigs compared with controls (31.0%; P = .004). The fibrosis and echocardiographic deformation data correlated in the posterior walls: rest peak SR(sys)r = -0.92; epsilon(sys)r = -0.86; 10 microg dobutamine stimulation peak SR(sys)r = -0.88, epsilon(sys), r = -0.87 (P = .0001). CONCLUSION: Endocardial injection of stem cells may induce cardioprotective effects in chronic ischemic myocardium and helps to keep the ischemic myocardium viable.

Strain rate imaging for functional quantification of the left atrium: atrial deformation predicts the maintenance of sinus rhythm after catheter ablation of atrial fibrillation.

AIMS: The aim of the study was to investigate the atrial myocardial deformation properties using ultrasound strain rate (SR) imaging in patients after catheter ablation of atrial fibrillation (AF) and to compare its prognostic value in maintaining sinus rhythm. METHODS AND RESULTS: A total of 118 patients with AF (74 paroxysmal AF, 44 persistent AF) underwent transthoracic echocardiography with Doppler-derived SR examinations before and after ablation as well as during 3 months of follow-up (FU). Peak SR and strain (S) were measured at each left atrium (LA) segment (septal, lateral, anterior, inferior) during systole (LAs) and at early (LAe) and late diastole (LAa). Clinical and echocardiographic parameters of patients with maintained sinus rhythm during FU were compared with those with recurrent AF and controls (n = 25 patients). Of 118 patients 82 (69%) showed stable sinus rhythm during FU. Atrial myocardial properties after catheter ablation differed significantly in patients with paroxysmal AF (SR-LAs 2.5 s(-1), S-LAs 30%, SR-LAa -2.2 s(-1)) from patients with persistent AF (SR-LAs 2.3 s(-1), S-LAs 25%, SR-LAa -1.9 s(-1)) and controls (SR-LAs 4.1 s(-1), S-LAs 88%, SR-LAa -2.9 s(-1)) (P = 0.011). Best individual predictors of sinus rhythm maintenance were cut-off values of >2.25 s(-1) for septal and inferior SR-LAs and of >19.5% for inferior S-LAs (P < 0.001). LA deformation properties increased in patients with maintained sinus rhythm during FU in contrast to patients with recurrent AF (P = 0.001). CONCLUSION: SR imaging enables the quantitative assessment of the LA function and can be considered as a potential marker of atrial reverse remodelling. Patients with higher atrial S and SR after catheter ablation appear to have a greater likelihood of maintenance of sinus rhythm. This may have further implications for the anticoagulation regime and the risk of cardioembolic complications.

Transesophageal echocardiography: a follow-up tool after catheter ablation of atrial fibrillation and interventional therapy of pulmonary vein stenosis and occlusion.

BACKGROUND: Pulmonary vein stenosis (PVS) has been described as a complication after primary catheter ablation of atrial fibrillation (Afib). The purpose of this study was to evaluate the utility of transesophageal echocardiography (TEE) as follow-up tool after catheter ablation of Afib and interventional therapy of PVS and pulmonary vein occlusion (PVO). METHODS: We report on 28 patients with stenosis (PVS) of 33 pulmonary veins (PVs) and total PVO of 4 veins complicating ablation of Afib assessed by angiography and/or magnetic resonance imaging (MRI). Subsequently, transseptal PV angiograms were performed, followed by recanalization of three totally occluded PVs and balloon dilatation of seven severe PVS (in four cases combined with PV stenting). PVs were analyzed by multiplane TEE in an intraindividual comparison of preablation/preintervention and follow-up measurements of mean and peak flow velocity, velocity time integrals, and diameters. RESULTS: Of a total of 28 patients, 14 had mild PVS (n = 14), 9 had moderate PVS (n = 10), 6 had severe PVS (n = 8), and 4 patients showed totally occluded PVs (n = 4). In multivariate analysis flow velocities and vessel diameters showed significant differences (mild, moderate, and severe PVS and PVO; p = 0.001). Interventional benefits of balloon dilatation (n = 10) and stent implantation (n = 4), as well as in-stent restenosis could be detected (p = 0.014). In all recanalized vessels TEE showed reestablished flow. In occluded PVs no flow was detectable. The TEE vessel diameters correlated with angiography data (r = 0.87) and computed tomography/MRI (r = 0.90). CONCLUSIONS: TEE can be used as a follow-up tool after interventional therapy in patients after catheter ablation and acquired PVS/PVO. Restenosis/in-stent restenosis can be identified by analyzing the vessel diameters and blood flow characteristics.

Attenuation of cardiac remodelling by endocardial injection of erythropoietin: ultrasonic strain-rate imaging in a model of hibernating myocardium.

AIMS: The aim of this study was to investigate whether erythropoietin (EPO) has cardioprotective effects in a chronic myocardial ischaemia model regarding strain-rate imaging parameters during dobutamine stress echocardiography (DSE). METHODS AND RESULTS: An ameroid constrictor was placed around the circumflex artery in 13 pigs to induce hibernating myocardium by a chronic vessel occlusion. The pigs were randomized 14 days later: seven pigs receiving 10,000 U EPO and six pigs receiving placebo injected into the ischaemic region using a NOGAtrade mark-guided transendocardial catheter. At weeks 2 and 6, animals were examined by DSE, electromechanical mapping, and coronary angiography. During incremental dobutamine infusion, regional radial function was monitored by measuring peak systolic strain-rates (SRsys), systolic strains (epsilonsys), and post-systolic strains (epsilonps). At week 6, the animals were pathohistologically investigated. Echocardiography revealed 2.2+/-0.8 hypokinetic segments in the EPO-treated animals in comparison with 3.3+/-0.9 akinetic segments per animal in the controls. The mean ejection fraction was reduced in the control group (55+/-3 vs. 66+/-4%, P=0.057). Strain-rate imaging revealed ischaemic myocardium in EPO-treated animals and non-viable myocardium in the controls (P=0.0001). Histological analysis of the ischaemic region revealed a reduction of myocardial fibrosis (8+/-1 vs. 27+/-5%) in the EPO-treated group. The transmural extension of fibrosis and the echocardiographic deformation data correlated in the posterior walls (EPO group): epsilonsys at rest r=0.83; peak SRsys during dobutamine stimulation r=0.92, P=0.01. CONCLUSION: Endocardial EPO injection may induce cardioprotective effects in chronic ischaemic myocardium and helps to obtain the myocardial contractile reserve, objectified by ultrasonic strain-rate imaging.

Transesophageal echocardiography: a screening method for pulmonary vein stenosis after catheter ablation of atrial fibrillation.

AIMS: Pulmonary vein (PV) stenosis has been described as a complication after catheter ablation of atrial fibrillation. The aim of the study was to investigate the diagnostic role of transesophageal echocardiography (TEE) in the assessment of PV stenosis. METHODS: Ninety-one patients (71 men, mean age 57+/-16years), initially treated by catheter ablation of atrial fibrillation, underwent re-ablation because of arrhythmia recurrences. PV angiograms and TEE were performed before the first and second ablation. PVs were analysed in an intraindividual comparison by measurements of mean and peak flow velocity and of velocity time integrals and diameters. PV angiograms served as standard for assessment of PV stenosis. RESULTS: Sixteen of 91 patients developed PV stenoses as a consequence of the first ablation (13 mild PV stenoses, 4 moderate PV stenoses). All patients with PV stenosis were asymptomatic. In moderate PV stenosis (50-70%) a significant increase of blood flow parameters, reduction of vessel diameter, inhomogeneous blood flow and aliasing were demonstrated by TEE. Using quantitative TEE criteria moderate PV stenosis could be identified with a sensitivity of 84% and specificity of 98%. Detection of mild PV stenosis (30-50%) is challenging (sensitivity of 48% and specificity of 75%). CONCLUSIONS: TEE identifies significant PV stenosis by assessment of flow characteristics and vessel diameter and can thereby be used as a follow-up tool after catheter ablation of atrial fibrillation.

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.