Novel Transcatheter Mitral Prosthesis Designed to Preserve Physiological Ventricular Flow Dynamics.

BACKGROUND: Current mitral bioprostheses are akin to the aortic valve and therefore abolish the left ventricular (LV) physiological vortex. We evaluated the hemodynamic performance and the effects on intraventricular flow dynamics (IFD) of a novel mitral bioprosthesis that presents an innovative design mimicking the native valve. METHODS: A D-shaped self-expandable stent-bovine pericardium monoleaflet valve was designed to provide physiological asymmetric intraventricular flow. Transapical implantation was consecutively performed in 12 juvenile sheep. Postimplant studies using Doppler echocardiography and IFD using echo particle imaging velocimetry were obtained immediately after the implantation and at 3 months to assess the hemodynamic performance of the prostheses. RESULTS: There were 3 deaths during follow-up, 1 due to valve misplacement because of poor imaging visualization and 2 not valve related. The mean transvalvular gradient and effective orifice area were 2.2 ± 1.2 mm Hg and 4.0 ± 1.1 cm2 after implantation and 3.3 ± 1.5 mm Hg and 3.5 ± 0.5 cm2 at 3 months, respectively. LV vortex dimension, orientation, and physiological anticlockwise rotation were preserved compared with preoperative normal LV flow pattern. One animal showed a moderate paravalvular leak, others mild or none. LV outflow tract obstruction, valve thrombosis, and hemolysis were not observed. CONCLUSIONS: Our preclinical in vivo results confirm the good hemodynamic performance of this new transcatheter bioprosthesis with preservation of the physiological IFD. Clinical studies are needed to document whether these characteristics will foster LV recovery and improve the clinical outcome of patients with mitral regurgitation.

Features of degenerative mitral valve prolapse in the North East of China: repair characteristics, and short-term follow-up results.

BACKGROUND: We aimed to assess the clinical and echocardiographic characteristics of patients who underwent surgery for degenerative mitral valve prolapse (MVP) in our center, and its relation to outcomes. METHODS: We enrolled 117 consecutive patients from North-East China with an echocardiographic diagnosis of MVP related mitral regurgitation (MR) between April 2018 and November 2019. A complexity scoring system was used for valve anatomy, and patients were re-evaluated at 3-6 months after surgery. RESULTS: Most patients (57.3%) were 40-59 years old. Ejection fraction was <60% in one third, and pulmonary hypertension was present in 64.3% of operated patients. Etiology was myxomatous in 58.9%, with flail as main lesion. Leaflet involvement was posterior in 59.8% patients, anterior in 32.5%, bileaflet in 6%, and commissural in 25.6%. Lesion score was intermediate in >50% of patients, and myxomatous lesions scored higher compared to fibroelastic deficiency (FED). Degree of MR left atrial volume and estimated wedge pressure were significantly higher in intermediate and complex lesions. Repair was performed in 93/101 patients (95.8% success rate). No in-hospital major adverse events, nor deaths at follow-up were reported. Residual MR was ≤ mild in 86.7% of patients at follow-up and was associated with FED etiology and complex lesions. CONCLUSIONS: Compared to Western countries, in our sample of Chinese population degenerative severe MR occurred in younger patients. The MVP lesion characteristics are similar, can be accurately detected by non-invasive preoperative evaluation, allowing predictable results. Advanced tailored repair techniques allow excellent immediate and short-term results regardless of the underlying complexity.

Efficacy of esmolol as a myocardial protective agent during continuous retrograde blood cardioplegia.

OBJECTIVE: Esmolol, an ultra-short-acting beta-blocker, is known to attenuate myocardial ischemia-reperfusion injury. The aim of this study was to compare the effects of esmolol and potassium on myocardial metabolism during continuous normothermic retrograde blood cardioplegia. METHODS: Forty-one patients operated on for isolated aortic valve stenosis were randomly assigned to continuous coronary infusion with either potassium or esmolol during cardiopulmonary bypass. Myocardial metabolism was assessed by measuring the transmyocardial gradient of oxygen content indexed to left ventricular mass of glucose, lactate, and nitric oxide. To do so, blood samples were simultaneously withdrawn upstream (in the cardioplegia line) and downstream of the myocardium (in the left coronary ostium) 10 and 30 minutes after aortic crossclamping. RESULTS: Although the cardioplegia flow rate and pressure were similar, esmolol markedly reduced the transmyocardial gradient of oxygen content indexed to left ventricular mass compared with potassium: 13 +/- 6 vs 20 +/- 6 mL of oxygen per liter of blood per 100 g of myocardium, respectively, at 10 minutes and 16 +/- 8 vs 24 +/- 8 mL of oxygen per liter of blood per 100 g of myocardium, respectively, at 30 minutes (P =.009). Coronary glucose and lactate transmyocardial gradients were similar in both groups, indicating adequate myocardial perfusion in all patients at all times. In addition, during retrograde cardioplegia, esmolol showed a lower nitric oxide release compared with that caused by potassium (39 +/- 49 micro mol x L(-1) for potassium vs 14 +/- 8 micro mol x L(-1) for esmolol at 10 minutes and 39 +/- 47 micro mol x L(-1) for potassium vs 6 +/- 8 micro mol x L(-1) for esmolol at 30 minutes, P =.05). However, hemodynamic parameters and plasma troponin I levels remained unchanged postoperatively between the 2 types of cardioplegia. CONCLUSION: Esmolol provides potent myocardial protection in hypertrophied hearts, at least in part, by reducing myocardial oxygen metabolism.

Autologous skeletal myoblast transplantation for severe postinfarction left ventricular dysfunction.

OBJECTIVES: This phase I trial was designed to assess the feasibility and safety of autologous skeletal myoblast transplantation in patients with severe ischemic cardiomyopathy. BACKGROUND: Experimentally, myoblast grafting into postinfarction myocardial scars improves left ventricular function. METHODS: Ten patients were included on the basis of the following criteria: 1) severe left ventricular dysfunction (ejection fraction < or = 35%); 2) the presence of a postinfarction akinetic and nonviable scar, as assessed by dobutamine echocardiography and 18-fluorodeoxyglucose positron emission tomography; and 3) an indication of coronary bypass in remote areas. Skeletal myoblasts were grown from a biopsy taken at the thigh. RESULTS: An average of 871 x 10(6) cells (86% of myoblasts) were obtained after a mean period of 16 days and implanted uneventfully across the scar at the time of bypass. Except for one patient whose early death was unrelated to the cell transplantation, all patients had an uncomplicated postoperative course. Four patients showed delayed episodes of sustained ventricular tachycardia and were implanted with an internal defibrillator. At an average follow-up of 10.9 months, the mean New York Heart Association functional class improved from 2.7 +/- 0.2 preoperatively to 1.6 +/- 0.1 postoperatively (p < 0.0001), and the ejection fraction increased from 24 +/- 1% to 32 +/- 1% (p < 0.02). A blinded echocardiographic analysis showed that 63% of the cell-implanted scars (14 of 22) demonstrated improved systolic thickening. One noncardiac death occurred 17.5 months after transplantation. CONCLUSIONS: These preliminary data suggest the feasibility and safety of autologous skeletal myoblast transplantation in severe ischemic cardiomyopathy, with the caveat of an arrhythmogenic potential. New-onset contraction of akinetic and nonviable segments suggests a functional efficacy that requires confirmation by randomized studies.

Total replacement of the ascending aorta without circulatory arrest.

OBJECTIVE: If the aortic arch is clamped between the brachiocephalic trunk and the left common carotid artery and the brachiocephalic trunk is also clamped, the total ascending aorta can be replaced without circulatory arrest. Candidates for this technique need to have the following characteristics: preoperative demonstration of Willis polygon patency by means of transcranial Doppler ultrasonography, preoperative computed tomographic scan that shows no calcification in the arch or in the brachiocephalic trunk, and preoperative or intraoperative evidence of separate origins of the brachiocephalic trunk and the left common carotid artery. METHODS: In three different institutions (with different time frames in each) from December 2000 to December 2001, the possibility of replacing the total ascending aorta without circulatory arrest was evaluated in 14 cases. In 10 of them it was possible (feasibility of 71.4%). During the procedure continuous electroencephalographic monitoring was performed. RESULTS: No patient died in the early or midterm follow-up. None of the patients had any cerebral complications. The electroencephalographic activity was normal during the period of brachiocephalic trunk occlusion. In 5 patients a postoperative spiral computed tomographic scan showed good surgical results. CONCLUSIONS: The technique described here allows replacement of the total ascending aorta without circulatory arrest in selected cases. Furthermore, the evidence of lack of right cerebral hypoperfusion in all the procedures we performed allows future exploration of the possibility of avoiding cerebral monitoring.

The transplant of cardiac cells and myoblast skeletal cells in myocardial infarction

OBJETIVO:Comparar o resultado funcional e anátomo-patológico entre o transplante de células mioblásticas e cardíacas no infarto do miocárdio. MÉTODO: Realizado infarto da parede ântero-lateral do ventrículo esquerdo em 26 ratos Wistar, com ligadura da artéria coronária esquerda. Após cinco dias, os animais foram submetidos a ecocardiografia transtorácica para cálculo dos volumes sistólico (VSFVE) e diastólico (VDFVE) finais e da fraçäo de ejeçäo do ventrículo esquerdo (FEVE). Os animais foram divididos em três grupos: 1) controle (n=10), 2) células cardíacas adultas (n=8) e 3) células musculares esqueléticas adultas (n=8). Sete dias após o infarto do miocárdio, os animais foram reoperados por esternotomia mediana, sendo identificada a regiäo de fibrose no ventrículo esquerdo e nela, injetado 0.15ml de meio de cultura no grupo I, 8.5x106/0.15ml de células cardíacas heterólogas no grupo II e 8.5x106/0.15ml de células musculares esqueléticas heterólogas no grupo III. Todos os animais receberam ciclosporina (15mg/kg/dia). Após dois meses do transplante, realizou-se nova ecocardiografia avaliando os mesmos parâmetros. RESULTADOS: Após dois meses do transplante celular, o grupo I apresentou um decréscimo da FEVE (48.18 porcento vs. 33.25 porcento p=0.0003), sendo que houve um acréscimo dos VSFVE e VDFVE (0.308ml vs. 0.536ml p=0.026 e 0.597ml vs. 0.776ml p=0.054, respectivamente). No grupo II houve uma estabilizaçäo da FEVE (42.48 porcento vs. 41.31 porcento p=0.4968, respectivamente) e um discreto aumento do VDFVE (0.602ml vs. 0.771ml p=0.0711). O VSFVE variou de 0.358ml a 0.450ml p=0.0400. O grupo III apresentou um acréscimo da FEVE, VDFVE e VSFVE (40 porcento vs. 47.35 porcento p=0.0142, 0.643ml vs. 0.931ml p=0.0026 e 0.388ml vs. 0.491ml p=0.0557 (sem significância), respectivamente. O GIII apresentou um maior valor, considerado estatisticamente significativo, da fraçäo de ejeçäo do ventrículo esquerdo, em comparaçäo ao GI e ao GII (47.35 porcento + 6.89 porcento vs. 41.31 porcento + 8.46 porcento vs. 33.25 porcento + 12.41 porcento p=0.0200, respectivamente). Identificou-se uma diferença estatisticamente significativa da fraçäo de ejeçäo do ventrículo esquerdo entre o GIII e o GI, após dois meses do transplante (47.35 porcento + 6.891 porcento vs. 33.25 porcento + 12.41 porcento p=0.0213, respectivamente)...

O transplante celular no tratamento da isuficiência cardíaca / Cell transplantation in the therapy for heart failure

A insuficiência cardíaca tem sido um grave problema de saúde pública, e provavelmente será a doença cardiovascular predominante neste século. Como a morte dos cardiomiócitos é freqüentemente responsável pelo desenvolvimento da insuficiência cardíaca, uma opçäo terapêutica de recuperar a funçäo cardíaca é o transplante de células contráteis, principalmente os mioblastos esqueléticos. Os resultados promissores obtidos no âmbito experimental, levou ao primeiro estudo clínico na França, onde mioblastos esqueléticos estäo sendo implantados em áreas miocárdicas previamente infartadas, com promissores resultados parciais. Apesar do curto tempo de evoluçäo e do pequeno número de pacientes operados, o transplante celular representa uma opçäo interessante no arsenal terapêutico da insuficiência cardíaca