超声心动图技术评价人工瓣机能的临床研究

目的 应用经胸(TTE)和经食管超声心动图(TEE)评价二尖瓣(MV)或/和主动脉瓣(AV)置换术后人工机械瓣机能。方法 对201例MV或/和AV置换者频谱测量血流峰值速度和跨瓣压差,评估人工瓣反流及瓣周漏程度;二维超声观察人工瓣,测量手术前后左心房、左心室内径和左心室射血分数(LVEF)。结果 (1)相同瓣位StJude、G-K、On-x人工瓣前向峰值血流速度(Vmax)和跨瓣压差(△P)之间无显著差异。(2)164枚人工MV出现0级反流131例(79.88%),I级反流29例(17.68%);Ⅱ级2例(1.22%);瓣周漏2例(1.22%)。81枚人工AV69例(85.18%)无反流,12例(14.82%)轻度反流。(3)术后左心房、左心室较术前明显缩小,LVEF较术前减低。结论TTE对人工瓣活动、瓣周异常和血流动力学的评判简便易行,TEE具有进一步评价病变部位、程度及术中即刻评价手术效果的优点。     

经食管彩色多普勒血流成像对心脏侧倾碟瓣置换术后返流的估价

为探讨经食管超声心动图估价心脏碟瓣功能的价值,本文采用经胸壁及经食管二维彩色多普勒血流成像观测了38例侧倾碟瓣置换患者术后返流情况,结果表明,经食管超声心动图对二尖瓣位碟瓣返流检测的敏感性明显高于经胸壁超声心动图检查(71％:13％,P<0.001),且能更可靠地估价返流的程度和更准确地判断返流的类型;经食管彩色多酱勒血流成像时,探头紧靠左房提供了一个无阻挡的透声窗,克服了经胸壁探查时声能衰减以及人工瓣金属材料强烈反射及其声影位于左房的不足。因此,经食管超声心动图是检测二尖瓣位碟瓣返流的极有效手段。     

经食道超声心动图的临床应用

本文报告164例心脏大血管疾病经食道超声心动图(TEE)检查。手术证实心房血栓9例,TEE 检出8例,而经胸超声心动图(TTE)仅发现2例。36个机械二尖瓣,TEE 发现中～重度返流4例,轻度返流8例,余24例均有功能性返流。而 TTE 仅显示5例轻度返流。对89例主动脉病变,房水平分流等 TTE 图象不满意和/或提供的信息有限时,TEE均提供了满意的诊断结果。     

经食道心脏超声心动图在临床心脏外科中的应用价值

目的 评价多平面经食道超声心动图(TEE)在心外科的临床应用价值。方法 对209例经心脏外科手术证实心血管疾病患者进行回顾性研究，所有患者术前均采用经胸超声心动图(TTE)及TEE检查，采用诊断符合率比较，评价TTE、TEE的临床应用价值。结果 在主动脉瓣狭窄、二尖瓣狭窄、房间隔缺损、瓣膜关闭不全、感染性心内膜炎、左房血栓、主动脉病变的诊断符合率方面TEE明显优于TTE(P＜0．05)。而在三尖瓣狭窄、肺动脉瓣狭窄、室间隔缺损、动脉导管未闭、左房粘液瘤的诊断符合率方面未见明显差异，但部分结果可能与病例数少有关。结论 TTE是常规诊断多种心血管疾病必要手段，多平面TEE较TTE有更为准确的诊断价值，且有利于指导心导管或手术治疗、判断病情、预后。     

超声心动图诊断成人先天性左房室瓣穿孔的价值

目的 探讨超声心动图[经胸超声(TTE),或经食管超声(TEE)]诊断先天性左房室瓣穿孔价值.方法 对3例经TTE或TEE诊断的成人先天性左房室瓣穿孔患者的超声心动图诊断资料进行分析,将超声结果与手术结果进行对照.结果 3例成人先天性左房室瓣叶穿孔所致的左房室瓣关闭不全病例,由于本组的发病年龄,临床上需要与先天性心脏瓣膜病(风湿性及其他)鉴别,临床及超声发现其他先心病的证据,尤其是TTE或TEE二维超声显示瓣叶中断,及彩色多普勒血流显像显示瓣膜偏心性高速血流,且临床上可以排除感染性心内膜炎,皆有助于先天性左房室瓣穿孔诊断.结论 TTE和TEE检查是早期诊断先天性左房室瓣穿孔的首选方法.TEE检出先天性左房室瓣穿孔优于TTE.     

经食管超声评估风湿性房颤栓塞危险性的价值

目的　探讨经食管超声心动图 (TEE)评估风湿性房颤患者栓塞危险性的价值。方法　 10 6例心房颤动患者分为风湿性房颤组 (n =5 1)和特发性房颤组 (n =5 5 ) ,所有患者同时进行TTE和TEE检查 ,对两组间左房自发性超声对比现象 (leftatrialspontaneousechocontrast,LASEC)的严重程度、LA、LVd、LVs、FS、二尖瓣瓣口面积等进行比较。结果　 10 6例中经TEE检查发现 14个血栓 ,而TTE检查仅发现 4个血栓 ,两组间左房血栓发生率、LASEC的严重程度、LA、FS及二尖瓣瓣口面积均有显著差异 (P <0 0 5 ) ,相关分析显示LASEC与LA呈显著正相关 ,与二尖瓣瓣口面积显著负相关。结论　风湿性房颤患者左房血栓发生率高 ,发生栓塞危险性较大 ,应积极抗凝治疗。TEE对于房颤患者血栓的检测及栓塞危险性的评估较TTE更有优势 ,LASEC、LA、二尖瓣瓣口面积可作为房颤患者左房血栓形成的预示因子。     

食管超声心动图在重危心脏病人诊断治疗中的价值

目的　为评价食管超声心动图 (TEE)在重危心脏病人诊断治疗中的价值 ,对 3 7例收住监护病房的重症心血管病人进行了经胸超声心动图 (TTE)和TEE检查 ,其中男 2 5例 ,女 1 2例 ,平均年龄57( 1 9～ 85)岁。入选对象包括怀疑夹层动脉瘤 2 3例、心脏瓣膜功能异常 9例、感染性心内膜炎 3例 ,心内分流 2例。结果　所有病人均可耐受TEE检查 ,无并发症发生 ,TEE较TTE可提供更高的阳性诊断结果 ,阳性率分别为 65 0 %和 3 8 0 % ,在怀疑夹层动脉瘤者中 ,TEE检出夹层撕裂膜 1 4例 ;而TTE仅检出 7例 ,且图象欠清 ,检出部位有限。在 4例人工机械瓣膜功能异常者中 ,TEE发现瓣膜部位血栓形成 3例。结论　在对心脏大血管疾病的诊断中 ,TEE阳性诊断率高于TTE ,尤其在怀疑夹层动脉瘤及人工机械瓣膜病变时 ,应行TEE检查。即使在重危病人 ,TEE也是一种安全有效的诊断手段。     

经食管及经胸超声心动图对风湿性心脏病左心房及左心耳血栓的诊断价值

目的　研究多平面经食管超声心动图 (TEE)及经胸超声心动图 (TTE)对风湿性心脏病 (RHD)左心房及左心耳血栓的诊断价值。方法　对同期 TTE检查的 469例和欲行二尖瓣球囊扩张术、闭式分离术、经 TTE检查未发现明确血栓而行 TEE检查的12 6例 RHD病人其左心房血栓 (LAT)及左心耳血栓 (L AAT)的检出情况进行总结分析。结果　 TTE:469例检出血栓者 2 1例。血栓位于左心房内 10例 ,左心房与左心耳并存者 7例 ,单纯左心耳部 4例。 TEE:12 6例中检出血栓者 3 2例 ,其中左心耳部血栓 2 4例 ,与左心房并存者 6例 ,单纯左心房内 1例。结论　 TEE对 L AAT的检出率显著高于 TTE,特别是对左心耳内及左心房周边的小血栓、新鲜血栓及血栓形成前状态优甚于 TTE。心房颤动可促成血栓的形成。对伴有心房颤动的 RHD患者用 TEE检查对 L AT及 L AAT的诊断具有重要价值     

经食管超声心动图对心脏瓣膜成形术的监测评估研究

目的　探讨术中经食管超声心动图 (TEE)在心脏瓣膜成形术中的应用价值及疗效评估。方法　研究对象为 79例进行二尖瓣成形术及三尖瓣成形术的患者 ,TEE全程监测整个手术过程 ,开胸前观察二尖瓣 ,三尖瓣及其附属结构的形态、功能及反流程度 ,瓣膜成形完成心脏复跳后 ,再次观察成形瓣膜及其附属结构的形态、功能及反流情况。结果　 5 6例三尖瓣成形术 ,术前均为重度三尖瓣关闭不全 ,成形术后 46例反流为轻度 ,6例反流完全消失 ,4例反流为中度。2 3例二尖瓣成形术 ,术前均为重度反流 ,反流面积与左心房面积之比达 44 %～ 90 %,成形术后 14例为轻度反流 ,反流面积与左心房面积之比 3 %～ 11%;8例反流完全消失。 1例成形术后反流仍为重度 ,接受了二尖瓣置换术。结论 :术中 TEE是唯一能够即刻评估心脏手术疗效的影像手段 ,其应用有助于改善瓣膜成形术的成功率 ,减少手术并发症 ,以及避免再次手术     

主动脉夹层的彩色多普勒血流显像与磁共振成像对比研究

目的　彩色多普勒血流显像与磁共振 (MRI)对主动脉夹层的对比研究。方法　对 3 0例经胸超声心动图 (TTE)、经食管超声心动图 (TEE)及 MRI诊断主动脉夹层患者进行分析研究 ,评价 TTE、TEE与 MRI对主动脉夹层分型及其并发症的诊断价值。结果　TTE、TEE和 MRI对主动脉夹层诊断的敏感性分别为 90 %、96%和 10 0 %。结论　 TTE对主动脉夹层分离的诊断有较高的敏感性 ,可作为首选检查方法 ,TEE和 MRI可明显提高其诊断敏感性和特异性     

Comparison of transthoracic and transesophageal assessment of prosthetic valve dysfunction

Transesophageal echocardiography has added another dimension to the assessment of prosthetic valve dysfunction with high-resolution images that allow for more detailed structural evaluation of tissue and mechanical valves. This study is a retrospective analysis of 140 prosthetic valves (90 tissue, 50 mechanical) in the mitral (89), aortic (45), and tricuspid (6) position in 116 patients studied by transthoracic and transesophageal echocardiography techniques. Transesophageal echocardiography was consistently better than the transthoracic technique in the evaluation of structural abnormalities of tissue valves in the mitral and aortic positions with respect to leaflet thickening, prolapse, flail, and vegetations. With transesophageal echocardiography, five tissue mitral valves had flail leaflets that were not identified by the transthoracic technique. Transesophageal echocardiography was better than transthoracic in the detection, quantification, and localization of prosthetic mitral regurgitation. Physiological mitral regurgitation was detected in 31 valves by transesophageal echocardiography compared to seven by transthoracic technique. By transesophageal echocardiography, mitral regurgitation was paravalvular in 24% compared with 4% by transthoracic technique. Left atrial spontaneous contrast was seen in 42% of the patients with a mitral prosthesis detected only by transesophageal echocardiography. Six patients had left atrial or left atrial appendage thrombus and in five patients they were detected only by transesophageal echocardiography. We conclude that transesophageal echocardiography should be a complimentary test to transthoracic studies in patients with suspected prosthetic valve dysfunction or for the follow-up of older tissue valves.     

Comparative value of transthoracic and transoesophageal echocardiography before balloon dilatation of the mitral valve.

OBJECTIVE--To assess the relative merits of transthoracic and transoesophageal echocardiography before balloon dilatation of the mitral valve. DESIGN--Transthoracic and transoesophageal echocardiograms were prospectively performed in 35 patients being considered for balloon dilatation of the mitral valve. Echocardiograms were analysed for image quality, the assessment of valve morphology, the detection of left atrial thrombus, and the assessment of mitral regurgitation and other valvar pathology. PATIENTS--35 consecutive patients with symptomatic dominant mitral stenosis. INTERVENTIONS--30 eventually underwent balloon dilatation of the mitral valve by the Inoue technique. Five patients had mitral valve replacement. MAIN OUTCOME MEASURES--Echocardiographic and surgical detection of left atrial thrombus and successful, uncomplicated balloon dilatation of the mitral valve. RESULTS--Left atrial thrombus was detected in 1/35 patients by transthoracic studies compared with 6/35 from transoesophageal studies. Otherwise both techniques gave comparable results. Thrombus was confirmed at mitral valve replacement in five patients. Successful dilatation of the mitral valve was performed in 30 patients. CONCLUSIONS--Transthoracic echocardiography is a useful screening procedure but transoesophageal echocardiography is mandatory before balloon dilatation of the mitral valve for the detection of left atrial thrombus.     

Location, size and morphological characteristics of left atrial thrombi as assessed by echocardiography in patients with rheumatic mitral valve disease.

AIMS: This study aimed to assess the use of transthoracic and transoesophageal echocardiography in diagnosing the thrombi located in the left atrium and/or left atrial appendage in patients with rheumatic mitral valve disease, and to investigate the characteristics of thrombi in comparison to intraoperative findings. METHODS AND RESULTS: The study group was comprised of 474 patients who underwent transthoracic and transoesophageal echocardiography prior to mitral valve surgery. Location, thickness and morphological characteristics of thrombi were determined by transoesophageal echocardiography. Intraoperative assessment disclosed left atrial thrombi in 105 patients. Thickness of thrombi < or = 1cm, and thrombi confined to left atrial appendage were associated with false-negative results by transthoracic echocardiography. However, diameter and morphological characteristics of thrombi, left atrial and left atrial appendage size, and the presence of the spontaneous echo contrast were not associated with the diagnosis of thrombi by transthoracic echocardiography. For overall left atrial thrombi, sensitivity and specificity of transthoracic echocardiography were 32%, and 94%, respectively. Sensitivity and specificity of transoesophageal echocardiography for thrombi in the left atrial appendage were 98%, and 98%, for thrombi in the main left atrial cavity were 81%, and 99%, and for thrombi located in both left atrium and appendage cavities were 100%, and 100%, respectively. CONCLUSION: In patients with rheumatic mitral valve disease, detection of left atrial thrombi by transthoracic echocardiography seems to be determined by thickness and location of thrombi. The multilobed structure of the left atrial appendage and artifacts over posterior wall of the left atrium may still prevent precise diagnosis even with transoesophageal echocardiography.     

Single-plane transesophageal echocardiography for assessing function of mechanical or bioprosthetic valves in the aortic valve position.

To assess the value and limitations of single-plane transesophageal echocardiography in the evaluation of prosthetic aortic valve function, 89 patients (69 mechanical and 20 bioprosthetic aortic valves) were studied by combined transthoracic and transesophageal 2-dimensional and color flow Doppler echocardiography. In the assessment of aortic regurgitation, the transthoracic and transesophageal echocardiographic findings were concordant in 71 of 89 patients (80%). In 8 patients, the degree of aortic regurgitation was underestimated by the transthoracic approach; in each case the quality of the transthoracic echocardiogram was poor. In 10 patients, transesophageal echocardiography failed to detect trivial aortic regurgitation due to acoustic shadowing of the left ventricular outflow tract from a mechanical valve in the mitral valve position. Transesophageal echocardiography was superior to transthoracic echocardiography in diagnosing perivalvular abscess, subaortic perforation, valvular dehiscence, torn or thickened bioprosthetic aortic valve cusps, and in clearly distinguishing perivalvular from valvular aortic regurgitation. Transesophageal echocardiography correctly diagnosed bioprosthetic valve obstruction in 1 patient, but failed to diagnose mechanical valve obstruction in another. In conclusion, transesophageal echocardiography offers no advantage over the transthoracic approach in the detection and quantification of prosthetic aortic regurgitation unless the transthoracic image quality is poor. Transesophageal echocardiography is limited in detecting mechanical valve obstruction and in detecting aortic regurgitation in the presence of a mechanical prosthesis in the mitral valve position. However, it is superior to transthoracic echocardiography in identifying perivalvular pathology, differentiating perivalvular from valvular regurgitation and in defining the anatomic abnormality responsible for the prosthetic valve dysfunction. Combined transthoracic and transesophageal examination provides complete anatomic and hemodynamic assessment of prosthetic aortic valve function.     

经胸与经食管超声心动图对心脏人工瓣膜的对比研究

４７例心脏人工机械瓣膜置换术后的病人，经胸超声心动图（ＴＴＥ）和经食管超声心动图（ＴＥＥ）对比研究显示，低估二尖瓣置换后人工瓣膜返流程度的分级和返流的发生率；主动脉瓣和二尖瓣置换的病人，ＴＴＥ探查人工二尖瓣返流的效果硬差。ＴＥＥ能较容易地探查人工二尖瓣瓣周漏。揭示对人工二尖瓣的评价，ＴＥＥ比ＴＴＥ能提供更多更可靠的信息，毫无疑问这是由于ＴＴＥ检查时人工瓣膜材料的声衰减和血流掩盖的影响，但我们的经验揭示，在评价主动脉瓣置换人工瓣膜时，ＴＥＥ并不优于ＴＴＥ。     

Use of transoesophageal echocardiography to detect left atrial thrombi before percutaneous balloon dilatation of the mitral valve: a prospective study.

OBJECTIVE--Systemic emboli related to atrial thrombi are a well known complication of percutaneous balloon dilatation of the mitral valve. The presence of left atrial thrombi therefore, is believed to be a contraindication to balloon dilatation. The purpose of this study was to determine the frequency of left atrial thrombi in patients referred for balloon dilatation of the mitral valve, the added benefit of pre-procedural transoesophageal echocardiography, and to identify factors that predicted left atrial thrombi. DESIGN--Prospective study over a 14 month period of 20 consecutive patients by cross sectional transthoracic echocardiography 24-48 hours before balloon dilatation of the mitral valve and by transoesophageal echocardiography immediately before the procedure. RESULTS--One patient had a left atrial thrombus detected by transthoracic study. Two patients (10%) had left atrial thrombi identified by transoesophageal echocardiography. In both valve dilatation was not attempted and the thrombi were confirmed at surgery. The remaining 18 patients all underwent successful balloon dilatation of the mitral valve without clinical evidence of an embolic event. No association was found between patient age, mitral valve area, transmitral gradient, left atrial size, presence of atrial fibrillation, severity of mitral regurgitation, cardiac output, or the presence of left atrial swirling and an increased prevalence of atrial thrombi. CONCLUSION--Left atrial thrombi are often seen despite long term systemic anticoagulation in patients referred for balloon dilatation of the mitral valve. The frequency of unsuspected left atrial thrombi detected by transoesophageal echocardiography was similar to the reported frequency of embolic events after balloon dilatation of the mitral valve. Transoesophageal echocardiography for the identification of left atrial thrombi is strongly recommended in all patients before balloon dilatation of the mitral valve including those treated with systemic anticoagulation and those who have had a normal transthoracic echocardiographic study.     

Use of transoesophageal echocardiography to detect left atrial thrombi before percutaneous balloon dilatation of the mitral valve: a prospective study.

OBJECTIVE--Systemic emboli related to atrial thrombi are a well known complication of percutaneous balloon dilatation of the mitral valve. The presence of left atrial thrombi therefore, is believed to be a contraindication to balloon dilatation. The purpose of this study was to determine the frequency of left atrial thrombi in patients referred for balloon dilatation of the mitral valve, the added benefit of pre-procedural transoesophageal echocardiography, and to identify factors that predicted left atrial thrombi. DESIGN--Prospective study over a 14 month period of 20 consecutive patients by cross sectional transthoracic echocardiography 24-48 hours before balloon dilatation of the mitral valve and by transoesophageal echocardiography immediately before the procedure. RESULTS--One patient had a left atrial thrombus detected by transthoracic study. Two patients (10%) had left atrial thrombi identified by transoesophageal echocardiography. In both valve dilatation was not attempted and the thrombi were confirmed at surgery. The remaining 18 patients all underwent successful balloon dilatation of the mitral valve without clinical evidence of an embolic event. No association was found between patient age, mitral valve area, transmitral gradient, left atrial size, presence of atrial fibrillation, severity of mitral regurgitation, cardiac output, or the presence of left atrial swirling and an increased prevalence of atrial thrombi. CONCLUSION--Left atrial thrombi are often seen despite long term systemic anticoagulation in patients referred for balloon dilatation of the mitral valve. The frequency of unsuspected left atrial thrombi detected by transoesophageal echocardiography was similar to the reported frequency of embolic events after balloon dilatation of the mitral valve. Transoesophageal echocardiography for the identification of left atrial thrombi is strongly recommended in all patients before balloon dilatation of the mitral valve including those treated with systemic anticoagulation and those who have had a normal transthoracic echocardiographic study.     

Role of transoesophageal echocardiography in the diagnosis and management of aortic root abscess.

OBJECTIVE--To assess and compare the roles of transthoracic and transoesophageal echocardiography in the diagnosis and management of an aortic root abscess. DESIGN--To select patients with echocardiographic diagnosis of aortic valve endocarditis with and without an aortic root abscess and correlate this with a retrospective review of surgical and necropsy data. SETTING--Tertiary referral centre at a university teaching hospital. PATIENTS AND METHODS--34 patients with confirmed aortic valve endocarditis were treated over a four and a half year period. All patients underwent both transthoracic and transoesophageal echocardiography with 17 patients having biplane or multiplane imaging. RESULT--11 patients (32%) had an aortic root abscess. Transthoracic echocardiography identified four cases of aortic root abscess whereas transoesophageal echocardiography correctly detected all 11 cases and also detected complications including mitral aortic intervalvar fibrosa fistula in two patients and right atrial involvement in another two patients. Only biplane imaging was able to show an anterior aortic root abscess in one patient and the circumferential involvement of the aortic annulus in another two patients. All patients with an aortic root abscess were treated surgically after transoesophageal echocardiographic diagnosis. After operation, prosthetic aortic regurgitation was present in seven patients and a repeat operation was performed in three patients. Only transoesophageal echocardiography detected a postoperative aorto-right atrial fistula in two patients and recurrence of the root abscess in another. There were five deaths in hospital (45%). CONCLUSIONS--Compared with transthoracic echocardiography, transoesophageal echocardiography was more sensitive and more specific for the early diagnosis of aortic root abscess and its complications and facilitated both the preoperative and postoperative management of these patients. Biplane and multiplane imaging provide additional diagnostic information. All patients with suspected aortic valve endocarditis should have an early transoesophageal echocardiographic study.     

Incidence and predictive factors of mitral insufficiency in surgically treated aortic stenosis. Transthoracic and transesophageal ultrasonographic evaluation

Mitral regurgitation is common in adults with aortic stenosis. When severe, it may aggravate the clinical condition and pose an additional therapeutic problem. The authors studied 40 consecutive patients with severe surgical aortic stenosis prospectively by transthoracic echocardiography and pre-operative transoesophageal echocardiography to determine the incidence, mechanism and degree of mitral regurgitation and its eventual relationship to the aortic stenosis. Mitral regurgitation was detected in all cases when both investigations were taken into consideration. It was usually mild, evaluated grade 2 by measuring the surface of the colour Doppler regurgitant jet, or mild to minimal of transoesophageal echocardiography in 35/40 patients (87.5% of cases). Rarely, a case of significant, autonomous mitral regurgitation (2 cases of valvular dystrophy, 1 pure severe mitral stenosis). On the other hand, calcification of the mitral annulus is common (14/40 patients, 35% of cases). The severity of the regurgitation in univariate analysis was significantly correlated mainly to the age of the patients (p = 0.027). The severity of the aortic stenosis (p = 0.0082) and the parameters related to the effects of stenosis, such as ventricular wall thickness and left atrial size. In multivariate analysis, the severity of the aortic stenosis and of its consequences were confirmed to play a role in the genesis of mitral regurgitation, the severity of which was correlated on transthoracic echocardiography to the aortic valve surface area and the left ventricular ejection fraction and, on transoesophageal echocardiography, to the transvalvular pressure gradient.     

Doppler echocardiography assessment of prosthetic heart valves

Transthoracic Doppler echocardiography is an accurate noninvasive method for the evaluation of prosthetic valve function. The flow characteristics and pressure gradients of normally functioning mechanical and bioprosthetic valves have been, in general established. Normal functioning mitral valve prostheses have a valve area > 1.8 cm² with the St. Jude valve having the largest effective valve area and normally functioning aortic prosthetic valves have a peak instantaneous gradient of < 45 mmHg, with the Starr-Edwards valves (Starr-Edwards, Irvine CA) showing the highest gradients. The incidence of minimal or mild regurgitation is approximately 15% to 30% in the mitral position and 25% to 50% in the aortic position, with the higher incidence of regurgitation seen with mechanical compared to bioprosthetic valves. Transthoracic Doppler echocardiography can accurately detect patients with prosthetic valvular stenosis. The presence of prosthetic aortic regurgitation can also generally be accurately assessed, except in the presence of both prosthetic aortic and mitral valves. Assessment of prosthetic mitral regurgitation remains limited due to significant attenuation of the ultrasound beam by the prosthesis and the frequent underestimation of severity of regurgitation. Other limitations of transthoracic studies include assessment of leaflet morphology, detection of vegetations and valve abscesses, and differentiation between valvular and paravalvular regurgitation.