Implantation of a stented elephant trunk into the descending aorta combined with replacement of the ascending aorta and total arch for acute type A aortic dissection is effective in closing the residual false lumen of the descending aorta and in preventing expansion of the descending aorta. However, further technical modifications, such as using a short stented elephant trunk, eliminating aortic clamping, shortening CPB and spinal cord ischemic time, and reconstruction of left subclavian artery, are needed to prevent neurologic complications.
A magnetically levitated (MagLev) centrifugal blood pump (CBP) with a disposable pump head has been designed to realize a safe, easy-to-handle, reliable, and low-cost extracorporeal blood pump system. It consisted of a radial magnetic-coupled driver with a magnetic bearing having a two-degree freedom control and a disposable pump head unit with a priming volume of 24 mL. The easy on-off disposable pump head unit was made into a three-piece system consisting of the top and bottom housings, and the impeller-rotor assembly. The size and weight of the disposable pump unit were 75 mm x 45 mm and 100 g, respectively. Because the structure of the pump head unit is easily attachable and removable, the gap between the electromagnets of the stator and the target material in the rotor increased to 1.8 mm in comparison to the original integrated bearing system of 1.0 mm. The pump performance, power requirements, and controllability of the magnetic bearing revealed that from 1400 to 2400 rpm, the pump performance remained fairly unchanged. The amplitudes of the X- and Y-axis rotor oscillation increased to +/- 24 microm. The axial displacement of the rotor, 0.4 mm, toward the top housing was also observed at the pump rpm between 1400 and 2400. The axial and rotational stiffness of the bearing were 15.9 N/mm and 4.4 Nm/rad, respectively. The MagLev power was within 0.7 Watts. This study demonstrated the feasibility of a disposable, magnetically suspended CBP as the safe, reliable, easy-to-handle, low-cost extracorporeal circulation support device.
BackgroundAfter restrictive mitral annuloplasty (RMAP) for functional mitral regurgitation (MR), the MR frequently recurs. Papillary muscle relocation (PMR) should reduce the recurrence rate. We assessed the influence of procedural differences in PMR on the postoperative mitral valve configuration.MethodsThirty-nine patients who underwent mitral valve repair for functional MR were enrolled. In limited tethering cases, RMAP alone was performed (RMAP group; n = 23). In severe tethering cases, in addition to RMAP, bilateral papillary muscles were relocated in the direction of the posterior annulus (posterior PMR group; n = 10) or anterior annulus (anterior PMR group; n = 6). We performed pre- and postoperative transthoracic echocardiographic studies, introducing a new index, mitral inflow angle (MIA), to assess the diastolic mitral leaflet excursion. MIA was measured as the angle between the mitral annular plane and the bisector of the anterior and posterior leaflets.ResultsPostoperative MR grade was significantly reduced in each group (P < 0.001). Follow-up echocardiography showed recurrent MR in 13% of the patients in RMAP group. In contrast, no recurrent MR was observed in either the anterior PMR or the posterior PMR group. After surgery, MIA was significantly reduced in both the RMAP group (P < 0.01) and the posterior PMR group (P < 0.001), but was preserved in the anterior PMR group (NS). None of the postoperative variables showed any significant difference between the early and late postoperative phases.ConclusionsIn the surgical treatment of functional MR, a PMR procedure in addition to RMAP was effective in reducing systolic MR. However, mitral valve opening assessed by MIA was restricted even after RMAP alone. The restriction was severely augmented after additional posterior PMR, but was attenuated after additional anterior PMR. The papillary muscle should be relocated in the direction of the anterior annulus to preserve the diastolic opening of the mitral valve.Electronic supplementary materialThe online version of this article (doi:10.1186/s13019-014-0185-6) contains supplementary material, which is available to authorized users.
Temporary BVP during the short-term after cardiac surgery improved cardiac function and decreased mitral regurgitation in all 4 of our patients. Epicardial lead implantation may thus be a useful option during surgical treatment of patients with CHF and intraventricular conduction delay if long-term permanent BVP is indicated.
Complications due to pump thrombus remain the weak point of mechanical circulatory support (MCS), such as the use of a left ventricular assist device (LVAD) or extracorporeal membrane oxygenation, leading to poor outcomes. Hyperspectral imaging (HSI) is an effective imaging method using a hyperspectral (HS) camera, which comprises a spectrophotometer and a charge-coupled device camera to discriminate thrombus from whole blood. Animal experiments were conducted to analyze dynamic imaging of thrombus inside a prototype of a hydrodynamically levitated centrifugal blood pump using an HSI system. Six pigs were divided into a venous circulation group (n = 3) and an arterial circulation group (n = 3). Inflow and outflow cannulae were inserted into the jugular veins in the venous circulation group. The latter simulated an LVAD application. To create thrombogenic conditions, pump flow was maintained at 1 L/min without anticoagulation. An image of the bottom surface of the pump was captured by the HS camera every 4 nm over the wavelength range of 608-752 nm. Real-time dynamic images of the inside of the pump were displayed on the monitor. Appearance of an area displaying thrombus was detected within 24 h after the start of the circulation in every experiment. This imaging system also succeeded in determining the origins of pump thrombus: from inside the pump in two cases, and from outside in four cases. Two main possible sources of pump thrombus originating outside the pump were identified on autopsy: wedge thrombus around the inflow cannula; and string-like thrombus at the junction between the pump inlet and circuit tube. The results of this study from close observation of the changing appearance of pump thrombus may contribute to improvements in the safety of extracorporeal MCS.
These data suggest that L-arginine pretreatment may reduce calcium overload by increasing cyclic guanosine monophosphate production, which in turn downregulates inositol triphosphate synthesis during reperfusion.
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