Shen-Kou Tsai

Comparison of Real Time Two-Dimensional with Live/Real Time Three-Dimensional Transesophageal Echocardiography in the Evaluation of Mitral Valve Prolapse and Chordae Rupture

We compared live/real time three‐dimensional transesophageal echocardiography (3D TEE) with real time two‐dimensional transesophageal echocardiography (2D TEE) in the assessment of individual mitral valve (MV) segment/scallop prolapse and associated chordae rupture in 18 adult patients with a flail MV undergoing surgery for mitral regurgitation. 2D TEE was able to diagnose the prolapsing segment/scallop and associated chordae rupture correctly in only 9 of 18 patients when compared to surgery. In three of these, 2D TEE diagnosed an additional segment/scallop not confirmed at surgery. In the remaining nine patients, surgical findings were missed by 2D TEE. On the other hand with 3D TEE, the prolapsed segment/scallop and associated ruptured chords correlated exactly with the surgical findings in the operating room in 16 of 18 patients. The exceptions were two patients. In one, 3D TEE diagnosed prolapse and ruptured chordae of the A3 segment and P3 scallop, while the surgical finding was chordae rupture of the A3 segment but only prolapse without chordae rupture of the P3 scallop. In the other patient, 3D TEE diagnosed prolapse and chordae rupture of P1 scallop and prolapse without chordae rupture of the A1 and A2 segments, while at surgery chordae rupture involved A1, A2, and P1. This preliminary study demonstrates the superiority of 3D TEE over 2D TEE in the evaluation of individual MV segment/scallop prolapse and associated ruptured chordae.

Live/real time three-dimensional transesophageal echocardiographic evaluation of mitral and aortic valve prosthetic paravalvular regurgitation.

Thirteen patients already scheduled for surgery for repair of prosthetic paravalvular regurgitation underwent intraoperative real time two‐dimensional transesophageal echocardiography (2D TEE) and live/real time three‐dimensional transesophageal echocardiography (3D TEE). In all patients, 3D TEE was able to provide more information regarding the location and size of the paravalvular defect as compared to 2D TEE. 3D TEE resulted in a more accurate localization of the defect and an estimation of the size of the defect that correlated much more closely with surgical findings when compared with 2D TEE. Our preliminary results demonstrate the superiority of 3D TEE over 2D TEE in the evaluation of paravalvular prosthetic regurgitation. 3D TEE not only provides an accurate assessment of the exact site of the leakage, but also gives a more accurate estimate of its size. This information could be valuable to surgeons who may encounter difficulty when localizing and estimating the size of paraprosthetic leaks while the heart is devoid of blood during surgery.

Baicalein Protects Against Retinal Ischemia by Antioxidation, Antiapoptosis, Downregulation of HIF-1α, VEGF, and MMP-9 and Upregulation of HO-1

PURPOSE Retinal ischemia-associated ocular disorders are vision threatening. This study examined whether the flavonoid baicalein is able to protect against retinal ischemia/reperfusion. METHODS Using rats, the intraocular pressure was raised to 120 mmHg for 60 min to induce retinal ischemia. In vitro, an ischemic-like insult, namely oxidative stress, was established by incubating dissociated retinal cells with 100 μM ascorbate and 5 μM FeSO4 (iron) for 1 h. The rats or the dissociated cells had been pretreated with baicalein (in vivo: 0.05 or 0.5 nmol; in vitro: 100 μM), vehicle (1% ethanol), or trolox (in vivo: 5 nmol; in vitro: 100 μM or 1 mM). The effects of these treatments on the retina or the retinal cells were evaluated by electrophysiology, immunohistochemistry, terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL) staining, Western blotting, or in vitro dichlorofluorescein assay. In addition, real-time-polymerase chain reaction was used to assess the retinal expression of hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase-9 (MMP-9), vascular endothelium growth factor (VEGF), and heme oxygenase-1 (HO-1). RESULTS The retinal changes after ischemia included a decrease in the electroretinogram b-wave amplitude, a loss of choline acetyltransferase immunolabeling amacrine cell bodies/neuronal processes, an increase in vimentin immunoreactivity, which is a marker for Müller cells, an increase in apoptotic cells in the retinal ganglion cell layer linked to a decrease in the Bcl-2 protein, and changes in the mRNA levels of HIF-1α, VEGF, MMP-9, and HO-1. Of clinical importance, the ischemic detrimental effects were concentration dependently and/or significantly (0.05 nmol and/or 0.5 nmol) altered when baicalein was applied 15 min before retinal ischemia. Most of all, 0.5 nmol baicalein significantly reduced the upregulation of MMP-9; in contrast, 5 nmol trolox only had a weak attenuating effect. In dissociated retinal cells subjected to ascorbate/iron, there was an increase in the levels of reactive oxygen species, which had been significantly attenuated by 100 μM baicalein and trolox (100 μM or 1 mM; a stronger antioxidative effect at 1 mM). CONCLUSIONS Baicalein would seem to protect against retinal ischemia via antioxidation, antiapoptosis, upregulation of HO-1, and downregulation of HIF-1α, VEGF, and MMP-9. The antioxidative effect of baicalein would appear to play a minor role in downregulation of MMP-9.

Baicalein Significantly Protects Human Retinal Pigment Epithelium Cells Against H2O2-Induced Oxidative Stress by Scavenging Reactive Oxygen Species and Downregulating the Expression of Matrix Metalloproteinase-9 and Vascular Endothelial Growth Factor

PURPOSE Age-related macular degeneration is a leading cause of blindness in the elderly. At a later stage, neovascular or exudative age-related macular degeneration can lead to severe central vision loss that is related to aging-associated cumulative oxidative stress of the human retinal pigment epithelium (hRPE) cells. Early prevention with antioxidants is mandatory. The aim of this study was to determine whether and how baicalein can act as an antioxidant. METHODS The methods used included lactate dehydrogenase, 2′,7′-dichloro-fluorescein diacetate, or enzyme-linked immunosorbent assay to measure cell viability, oxygen free radical levels, or the levels of vascular endothelial growth factor (VEGF)/matrix metalloproteinase-9 (MMP-9), respectively. RESULTS H₂O₂ dose-dependently reduced the cell viability of hRPE cells. This negative effect was dose-dependently (with a lower effect at 20µM) and significantly counteracted by pretreatment with baicalein (50µM). Treatment with H₂O₂ significantly stimulated the formation of oxygen free radicals. This increase was dose-dependently and significantly blunted by baicalein. Further, treatment with a sublethal dose of H₂O₂ was associated with an upregulation in the levels of VEGF and MMP-9. The increases in these proteins were also dose-dependently (with a lower effect at 20µM) and significantly (50µM) blunted by pretreatment with baicalein. CONCLUSION This study supports an antioxidative role for baicalein whereby it protects hRPE cells against H₂O₂-induced oxidative stress by downregulating the levels of VEGF and MMP-9, which are increased by H₂O₂.

The effects and underlying mechanisms of S-allyl l-cysteine treatment of the retina after ischemia/reperfusion.

PURPOSE Retinal ischemia-associated ocular disorders are vision-threatening. The aim of the present study was to examine whether S-allyl l-cysteine (SAC) is able to protect against retina ischemia/reperfusion injury. METHODS In vivo, retinal ischemia in the rat was induced by raising intraocular pressure (IOP) to 120 mmHg for 60 min. In vitro, an ischemic-like insult, namely oxidative stress, was established by incubating retinal ganglion cell-5 (RGC-5) with 500 μM H(2)O(2) for 24 h. The mechanisms involved in these processes were evaluated by electrophysiology, immunohistochemistry, and molecular biological approaches. RESULTS The retinal changes caused by the high IOP were characterized by a decrease in electroretinogram b-wave amplitudes, a loss of choline acetyltransferase immunolabeling amacrine cell bodies/neuronal processes, and an upregulation of the mRNA levels of hypoxia-inducible factor-1α (HIF-1α), vascular endothelium growth factor (VEGF), and matrix metalloproteinase-9 (MMP-9). The increased protein levels of HIF-1α, VEGF, and MMP-9 were also seen in RGC-5 cells subjected to defined oxidative stress. Of clinical importance, the ischemic/ischemic-like detrimental effects were concentration-dependently (least effect at 25 μM) and/or significantly (50 and/or 100 μM) blunted when SAC was applied 15 min before retinal ischemia or ischemic-like insult, respectively. CONCLUSION SAC would seem to protect against retinal ischemia by acting as an antioxidant and inhibiting the upregulation of HIF-1α, VEGF, and MMP-9.

Therapeutic Effects and Mechanisms of Action of Mannitol During H2O2-Induced Oxidative Stress in Human Retinal Pigment Epithelium Cells

BACKGROUND Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly. At a later stage, neovascular or exudative AMD can lead to severe central vision loss that is related to aging-associated cumulative oxidative stress of the human retinal pigment epithelium (hRPE) and choroid capillary. Early prevention with antioxidants is mandatory. The aim of this study was to determine whether and how mannitol can act as an antioxidant. METHODS The methods used included measurements of cell viability, oxygen free radical (OFR) levels, lipid peroxide (LP) levels, and OFR-related enzyme protein levels. RESULTS H(2)O(2) dose-dependently reduced the cell viability of hRPE cells. This negative effect was significantly counteracted by pretreatment with mannitol (1 mM). H(2)O(2) significantly stimulated the formation of OFR and LP. These increases were dose-dependently and significantly blunted by mannitol. Furthermore, treatment with H(2)O(2) was associated with a reduction in the level of catalase, but not of manganese superoxide dismutase (MnSOD). In contrast, it was shown that mannitol protected hRPE cells against the H(2)O(2)-induced oxidative stress by increasing the level of catalase, but not the level of MnSOD. CONCLUSION This study supports an antioxidative role for mannitol that acts through up-regulating the level of catalase, which is decreased by H(2)O(2).

Incremental value of live/real time three-dimensional transesophageal echocardiography over the two-dimensional technique in the assessment of aortic aneurysm and dissection.

We compared findings from intraoperative live/real time three‐dimensional transesophageal echocardiography (3DTEE) and two‐dimensional transesophageal echocardiography (2DTEE) with surgery in 67 patients having aortic aneurysm and/or aortic dissection. Of these, 20 patients had aortic aneurysm without dissection, 21 aortic aneurysm and dissection, and 26 aortic dissection without aneurysm. 3DTEE diagnosed the type and location of aneurysm correctly in all patients unlike 2DTEE, which missed an aneurysm in one case. There were four cases of aortic aneurysm rupture. Three of them were diagnosed by 3DTEE but only one by 2DTEE, and one missed by both techniques. The mouth of saccular aneurysm, site of aortic aneurysm rupture, and communication sites between perfusing and nonperfusing lumens of aortic dissection could be viewed en face only with 3DTEE, enabling comprehensive measurements of their area and dimensions as well as increasing the confidence level of their diagnosis. In all patients with aortic dissection, 3DTEE enabled a more confident diagnosis of dissection because the dissection flap when viewed en face presented as a sheet of tissue rather than a linear echo seen on 2DTEE which can be confused with an artifact. 2DTEE missed dissection in one patient. In six cases the dissection flap involved the right coronary artery orifice by 3DTEE and surgery. These were missed by 2DTEE. Aortic regurgitation severity was more comprehensively assessed by 3DTEE than 2DTEE. Aneurysm size by 3DTEE correlated well with 2DTEE and surgery/computed tomography scan. In conclusion, 3DTEE provides incremental information over 2DTEE in patients with aortic aneurysm and dissection. (Echocardiography 2012;29:620‐630)

The Ability of Live Three-Dimensional Transesophageal Echocardiography to Evaluate the Attachment Site of Intracardiac Tumors

In this study, a case of a right ventricular myxoma and a case of a right ventricular hemangioma are used to demonstrate the ability of live three‐dimensional transesophageal echocardiography (3DTEE) to assess the site of tumor attachment. Because 3DTEE has the ability to visualize desired structures in multiple planes, we defined the attached portion of the tumors and measured the en face view dimensions. In addition, the improved ability of 3DTEE to evaluate tissue characteristics allowed differentiation of the heterogeneous myxoma and highly vascular hemangioma. On the contrary, because two‐dimensional (2D) TEE only allows structures to be viewed in a 2D plane, the attachment site can be located but complete delineation and measurement of area is not possible. As surgical options become less invasive, accurate attachment site location and size will become more important to ensure complete excision. (Echocardiography 2011;28:1041‐1045)

The additional value of live/real-time three-dimensional transesophageal echocardiography over two-dimensional transesophageal echocardiography for assessing mitral regurgitation with eccentric jets

Background: Two‐dimensional transesophageal echocardiography (2D TEE) Doppler color flow imaging is the gold standard for assessing the severity of mitral regurgitation (MR). Severe MR with very eccentric jet may involve more than one mitral leaflet lesion and can be missed by 2D TEE. The purpose of this study was to assess the usefulness and the incremental value of real‐time three‐dimensional (RT 3D) TEE over 2D TEE findings in the evaluation of patients suffering eccentric MR with more than one mitral leaflet lesion. Methods: Intraoperative 2D TEE and RT 3D TEE examinations were performed on 168 patients with Carpenter II MR who underwent surgery. MR was defined as either central, free‐standing eccentric jet or very eccentric jet. 2D TEE and RT 3D TEE finding were compared with surgical findings. Results: Of these 168 MR patients, 25 patients (14.9%) had central jets and 143 patients (85.1%) had eccentric jets. Among 143 patients with eccentric jets, 47 patients (32.9%) had free‐standing eccentric MR jets, and 96 (67.1%) patients had very eccentric jets. 3D TEE diagnosed the severity and location of MR lesions correctly in all patients; this was not the case with 2D TEE, which had significant diagnostic misses in nine patients (9.4%, p < 0.001) having MR with very eccentric jets. These nine patients had lesions on both mitral leaflets, which were missed during 2D TEE examination owing to the highly turbulent flows produced by very eccentric jets from one mitral leaflet lesion and impinging the opposite mitral leaflet lesion. Conclusion: The severity of MR with very eccentric jet was more accurately and comprehensively assessed by 3D TEE than by 2D TEE. Therefore, intraoperative RT 3D TEE provides incremental information that is generally superior to 2D TEE in patients with complex MR due to very eccentric jets.

Intraoperative three-dimensional transesophageal echocardiography for assessing the defect geometries of mitral prosthetic paravalvular leak during transcatheter closure

Background Paravalvular leaks (PVLs) are a common complication of prosthetic valve replacement. Use of the transcatheter intervention technique is a suitable alternative in high‐risk patients who may not tolerate repeat surgery. Common reasons for failure of this demanding intervention include poor imaging quality and unsuitable anatomy. The purpose of this study was to assess the usefulness and the incremental value of real‐time three‐dimensional (RT 3D) transesophageal echocardiography (TEE) over two‐dimensional (2D) TEE findings in the evaluation of the geometry and track of mitral PVLs during transcatheter closure. Methods Five patients with six mitral PVLs at high risk for repeat surgery underwent transcatheter leak closure. Intraoperative RT 3DTEE was used to assess the location, shape, number, and size of the defects. Transapical approaches were used in all cases with fluoroscopic and RT 3D TEE guidance of the wire and catheter, device positioning, and assessment of residual leak after the procedure. Results In all of the cases, defects with irregular crescent shapes and distorted tracks were clearly delineated by RT 3D TEE. This was compared to those results obtained through 2D TEE, which was unable to characterize the defects. Three cases showed small leaks, which were completely occluded with a patent ductus arteriosus (PDA) device in two cases, and a muscular ventricular septal defect (mVSD) occluder combined with coil devices in one case. One case involved a large leak and early device embolization of the muscular VSD occluder, which was removed surgically, and demonstrated a crescent–shaped defect. One patient had two releaks 2 months subsequent to the procedure due to two new extended leaks at the tails of the crescent–shaped defect. Conclusion RT 3D TEE can clearly delineate the geometries of defects in their entirety, including shape, size, and location of the defect and track canal. It would also appear that RT 3D TEE is superior to 2D TEE in the process of guiding the wire through the difficult canal anatomy, facilitating the overall procedure. The small mitral PVLs can be completely occluded, but subsequent complications occurred with large defect closures because of embolization or releak. Therefore, transcatheter closure of PVLs seems to be an attractive alternative for these patients, but newer occluder designs that better conform to leak geometry will be required to improve outcomes.