Mechanical Prosthetic Valve Thrombosis: Case Report and Review of the Literature

Mechanical prosthetic valve thrombosis is a life-threatening complication necessitating immediate intervention. The presenting signs and symptoms of this illness are somewhat variable, but physical examination and transesophageal echocardiography enable rapid diagnosis. To avoid catastrophic complications, valve replacement or debridement, or thrombolysis in the correct setting, must be performed without delay. It is not entirely clear which therapy is superior. For any given patient, the risks of thrombolytic therapy, including bleeding, systemic embolism, and failure to restore valvular function, must be weighed against the risks of surgical intervention. Once the decision is made to operate, the choice of valve replacement versus debridement is one best made intraoperatively, upon visual inspection of the valve apparatus. Despite aggressive therapy, morbidity and mortality from prosthetic valve thrombosis and its treatment are not trivial. Fortunately, with current prosthetic devices and aggressive prophylactic anticoagulation, the incidence of prosthetic valve thrombosis remains low. Antiplatelet therapy may offer additional benefit to patients being prophylaxed with warfarin. This report details the case of a woman with aortic and mitral prosthetic valves who presented with heart failure and evidence of severe aortic prosthetic dysfunction after a period of suboptimal anticoagulation. She successfully underwent debridement of the mitral prosthesis and replacement of the aortic valve. The relevant literature is reviewed.     

全蝎纯化液对实验性动脉血栓形成t-PA、PAI-1的影响

目的观察全蝎纯化液对新西兰白兔颈总动脉血栓形成组织型纤溶酶原激活物(t-PA)、纤溶酶原活化物抑制剂(PAI-1)、血小板计数(Pt)的变化。方法将50只健康新西兰白兔随机分成5组:空白组、模型组、全蝎纯化液大剂量组(20mg/kg)、全蝎纯化液中剂量组(10mg/kg)和全蝎纯化液小剂量组(5mg/kg)。耳缘静脉注射药物(空白组、模型组注射同等体积的生理盐水)后,采用H2O2损伤新西兰白兔颈总动脉制备血栓模型,造模2h后,采血并取血栓,酶联免疫吸附法(ELISA法)检测血浆t-PA、PAI-1的含量。结果与空白组比较,模型组t-PA明显降低,PAI-1明显升高,差异有统计学意义(P<0.01);与模型组相比,全蝎纯化液各剂量组能明显抑制PAI-1活性,增加t-PA活性,差异均有统计学意义(P<0.01),而各组的血小板计数差异无统计学意义(P>0.05)。结论全蝎纯化液各剂量组可明显促进血浆t-PA的分泌,抑制血浆PAI-1活性,提示全蝎纯化液抗血栓作用机制可能与其促纤溶作用有关。     

构建重组组织纤溶酶原激活物基因质粒预防换机械瓣术后血栓

目的探讨构建的组织纤溶酶原激活物(tissueplaminogenactivator,t-PA)基因质粒对预防机械瓣膜置换术后血栓形成的作用。方法人工构建t-PA基因表达质粒,用阳离子质脂体包裹并制备成基因缝线。选择18只猪随机分为实验组和对照组,每组9只,行三尖瓣膜置换术的同时将基因缝线缝合于心肌组织,以超声波辅助转导心脏细胞产生高活性t-PA,观察术后瓣膜血栓形成、凝血功能和纤溶降解产物D-二聚体含量以及动物生存状况。结果成功构建了t-PA基因质粒并获得在心脏中表达。在对照组,于术后第1周血D-二聚体含量达高峰,平均(1.7±0.8)mg/L,于第2周明显下降接近术前;实验组于术后1周明显增高达(1.8±0.8)mg/L,与对照组差异无统计学意义(P>0.05);此后观察各期仍维持较高状态,术后2,4,8和12周检测值分别为(1.3±0.5)mg/L、(1.2±1.0)mg/L、(1.8±1.2)mg/L和(1.9±0.8)mg/L,比对照组均显著增高(P<0.01)。对照组瓣口和瓣周血栓形成率9/9,而实验组仅1/9(P<0.01)。结论构建的t-PA基因质粒可预防机械瓣膜置换术后血栓形成。     

Medium-Term Follow-Up of Early Leaflet Thrombosis After Transcatheter Aortic Valve Replacement

Objectives

The aim of this study was to investigate medium-term outcomes in patients with leaflet thrombosis (LT).

Evaluation of Platelet Kinetics following Porcine and Mechanical Valve Replacement

Because thromboembolic pathogenesis in mechanical prosthetic valves (MP) might involve selective MP platelet consumption with consequent reduced platelet survival, it has been suggested that lowered platelet half-life (T_1/2) detection provides identification of postoperative thrombotic risk. Porcine heterografts (PH) possess less thromboembolic hazards than MP; thus, comparative evaluation of PH versus MP platelet T_1/2 is germane to the test's thrombotic predictive value, yet platelet kinetics in PH require elucidation. Accordingly, ₅₁chromium platelet T1/2 was determined in 16 patients with substituted valves (10 PH and 6 MP). Average platelet T1/2 in PH (2.9±0.6 d) was similar (p>0.05) to MP (3.2±0.6 d), and both were considerably lower (p<0.05) than platelet T1/2 in normal subjects (NL, 5.1±0.5 d). Furthermore, platelet T1/2 was below the lowest NL platelet T_1/2 (4.0 d) in seven PH and three MP patients. Thus, frequency and extent of decreased platelet survival in PH are common and equal to MP. These results indicate that platelet half-life does not afford thromboembolic predictability in patients with mechanical valves and, instead, favors prosthetic-induced physical trauma causing abnormal platelet survival.     

Management of Nonobstructive Thrombosis of Prosthetic Mitral Valve in Asymptomatic Patients in the Early Postoperative Period: A Study in 20 Patients

The purpose of the present study was to determine the optimal management of nonobstructive thrombi in the early postoperative period after mitral valve replacement. Twenty cases of early thrombi were revealed by systematic transesophageal echocardiography (TEE) performed 9 days after surgical implantation of 229 St. Jude prostheses. Patients were prospectively randomized into two groups: the first group received oral anticoagulants (fluindione), and the second group was treated with a combination of oral anticoagulants and aspirin. The impact of the different therapies on prosthetic thrombi was assessed by systematic TEE at 5 months. All thrombi were nonobstructive and disappeared without fibrinolytic agents or surgery. Seven large (≥ 5 mm) thrombi disappeared: in two patients after reintroduction of intravenous heparin and in five patients with an optimized oral treatment (anticoagulants alone in one patient, anticoagulants associated with aspirin in four patients). In the 13 small (< 5 mm) thrombi, 11 disappeared with an optimized oral treatment: anticoagulants alone in nine patients and anticoagulants associated with aspirin in two patients. The other two small thrombi treated with heparin alone initially persisted and finally disappeared with heparin associated with aspirin. In the group with large thrombi, we recorded a 43% rate of thromboembolic events, with more deaths and severe cerebral embolic events than in the patients with small thrombi. Embolic events were associated with mobile thrombi. An optimized oral anticoagulation therapy with correction of the parameters of Virchow et al. is effective in the treatment of small prosthetic thrombi. For large thrombi, the high rate of thromboembolic events would appear to require a more aggressive approach such as an association of heparin with aspirin and TEE follow-up.     

非瓣膜性心房颤动患者凝血-纤溶系统活性的变化及临床意义

目的:探讨非瓣膜性心房颤动患者凝血-纤溶系统改变及其意义.方法:选择慢性非瓣膜性心房颤动患者(心房颤动组)54例,其中男28例,女26例,平均年龄(58.4±12.3)岁;存在相同心血管疾病(高血压或冠心病)的窦性心律者(窦性心律组)40例,男20例,女20例,平均年龄(57.6±11.7)岁;健康体检者35例为对照组,其中男17例,女18例,平均年龄(52.4±18.5)岁.测定以上3组患者血浆纤维蛋白原、D-二聚体、组织纤溶酶原激活剂、组织纤溶酶原抑制剂水平及凝血酶原时间、凝血酶时间和部分凝血活酶时间.结果:非瓣膜性心房颤动患者血浆纤维蛋白原、D-二聚体和组织纤溶酶原抑制剂水平显著升高,血浆组织纤溶酶原激活剂水平显著降低.凝血酶原时间、凝血酶时间和部分凝血活酶时间则无显著变化.结论:非瓣膜性心房颤动患者存在高凝和低纤溶状态.     

核素心室造影对保留二尖瓣的二尖瓣替换术临床疗效的初步评价

目的：评价保留二尖瓣的二尖瓣替换术临床效果。方法：采用平衡法核素心室造影，对１３例二尖瓣病变患者术前术后进行心功能测定。测定参数：左心室射血分数、局部射血分数、右心室射血分数及舒张末期与收缩末期的径线缩短率。结果：保留二尖瓣组（ｎ＝７）左心室射血分数术前术后无明显变化，左心室侧壁、下壁心尖部局部射血分数明显改善。不保留二尖瓣组（ｎ＝６），左心室射血分数于术前术后无明显变化，仅左心室侧壁局部射血分数改善。结论：保留二尖瓣的二尖瓣替换术对术后心功能的改善具有良好的效果，核素心室造影对评价手术疗效是一种有价值的无创性方法。     

心脏瓣膜置换术中心脏复跳前主动脉根部 灌注腺苷对心肌的保护作用

摘要: 目的 研究在心脏瓣膜置换术中心脏复跳前主动脉根部灌注腺苷对心肌的保护作用。 方法 42例行心脏瓣膜置换术患者随机分为两组,腺苷组在心脏瓣膜置换完成后,心脏复跳前主动脉根部灌注入外源性腺苷,对照组心脏复跳前不灌注外源性腺苷,按照常规处理。术前、主动脉开放后4h、12h、24h采集患者桡动脉血,测心肌型肌酸激酶同工酶(CK-MB)、肌钙蛋白I(cTn-I)。观察心脏停跳情况,术后机械通气时间及术后正性肌力药物的应用情况,心肌超微结构的改变。 结果 腺苷组的肌酸激酶同工酶水平在主动脉开放后4h、12h,肌钙蛋白I水平在主动脉开放后4h、12h、24h较对照组低。透射电镜见腺苷组心肌损伤较对照组明显减轻。 结论　在心瓣膜置换术中心脏复跳前主动脉根部灌注腺苷能显著提高心肌保护效果。     

脑血栓形成病人血浆及脑脊液t-PA及其PAI-1含量的观察

目的：研究动脉粥样硬化性脑血栓形成病人血浆及脑脊液组织型纤溶酶原激活物（t-PA)及其抑制物（PAI-1）含量的变化及其临床意义。方法：采用双抗体夹心固相酶联免疫吸附法（ELISA）检测35例脑血栓形成病人血浆和其中31例病人脑脊液t-PA及PAI-1抗原含量，与35例正常对照组血浆和其中20例对照组脑脊液进行比较。结果；脑血栓形成组血浆t-PA含量高于对照组，PAI-1含量显著高于对照组；其脑脊液t-PA,PAI-1含量均显著高于对照组，脑脊液中t-PA,PAI-1的含量分别与血浆中t-PA,PAI-1的含量，分别与血浆中t-PA,PAI-1的含量呈正相关；脑血栓形成组病人神经功能缺损评分与血浆及脑脊液t-PA,PAI-1抗原含量呈正相关。结论：脑血栓形成病人纤溶活性明显下降，t-PA及PAI-1参与了脑血栓形成之病理过程；t-PA及PAI-1抗原含量是反映体内纤溶活性的两个重要指标；可用血浆或脑脊液t-PA,PAI-1的含量作为判断病情的参考指标之一。     

重度主动脉瓣狭窄瓣膜置换术后左室舒张功能的超声评价

目的应用常规超声心动图及斑点追踪二维应变技术研究EF正常的单纯重度主动脉瓣狭窄患者,评价瓣膜置换术后左室重构与左室舒张功能改善的情况并进行相关性分析。方法20例单纯重度主动脉瓣狭窄患者于手术前、术后平均7．5个月行经胸超声心动图检查。比较术前与术后左室舒张末期容积指数（LVEDVI）、左室心肌质量指数（LVMI）、室壁相对厚度（RWT）、左室充盈压（E／E’m）、等容舒张期左室整体应变率（SRIVRT）、舒张早期左室整体应变率（SRE）及其变化的相关性。结果主动脉瓣置换术后LVEDVI、LVMI、LVMI／LVEDVI均较术前减低（P均〈0．05）,SRIVRT、SRE均较术前升高（P均〈0．05）;RWT、E／E’m较术前改变不显著（P均〉0.05）。SRIVRT与SRE正相关（r=0．403,P〈0．05）,术前的SRIVRT与E／Em’及LVMI／LVEDVI呈负相关（P均〈0．05）。结论EF正常的单纯主动脉瓣狭窄患者在主动脉瓣置换术后左室重构的主要变化为左室容量减小,左室壁心肌质量下降,虽然左室充盈压无明显下降,但SRIVRT和SRE在术后有所升高,可作为补充指标更敏感地反映左室整体舒张功能的变化。     

急性心肌缺血氧自由基与血液高凝状态的实验研究

本文研究急性心肌缺血氧自由基及其清除剂对抗凝血酶及纤溶系统的影响。结果表明:心肌缺血4小时引起血浆丙二醛(MDA)增高,血浆抗凝血酶Ⅲ(AT-Ⅲ)及组织型纤溶酶原激活剂(t-PA)活性降低。纤溶酶原激活剂抑制物(PAI)活性增高。MDA与AT-Ⅲ呈负相关,与PAI呈正相关。自由基清除剂超氧化物歧化酶(SOD)及过氯化氢酶(CAT)可降低自由基,升高AT-Ⅲ与t-PA活性,降低PAI活性。作者认为氧自由基可能对急性心肌缺血产生高凝状态起重要作用。     

Transcatheter Aortic Valve Replacement for Residual Lesion of the Aortic Valve Following “Healed” Infective Endocarditis

ObjectivesThis study aimed to evaluate the safety and mid-term efficacy of transcatheter aortic valve replacement (TAVR) in the setting of aortic valve (AV) infective endocarditis (IE) with residual lesion despite successful antibiotic treatment.BackgroundPatients with AV-IE presenting residual lesion despite successful antibiotic treatment are often rejected for cardiac surgery due to high-risk. The use of TAVR following IE is not recommended.MethodsThis was a multicenter retrospective study across 10 centers, gathering baseline, in-hospital, and 1-year follow-up characteristics of patients with healed AV-IE treated with TAVR. Matched comparison according to sex, EuroSCORE, chronic kidney disease, left ventricular function, prosthesis type, and valve-in-valve procedure was performed with a cohort of patients free of prior IE treated with TAVR (46 pairs).ResultsAmong 2,920 patients treated with TAVR, 54 (1.8%) presented with prior AV-IE with residual valvular lesion and healed infection. They had a higher rate of multivalvular disease and greater surgical risk scores. A previous valvular prosthesis was more frequent than a native valve (50% vs. 7.5%; p < 0.001). The in-hospital and 1-year mortality rates were 5.6% and 11.1%, respectively, comparable to the control cohort. After matching, the 1-year III to IV aortic regurgitation rate was 27.9% (vs. 10%; p = 0.08) and was independently associated with higher mortality. There was only 1 case of IE relapse (1.8%); however, 18% of patients were complicated with sepsis, and 43% were readmitted due to heart failure.ConclusionsTAVR is a safe therapeutic alternative for residual valvular lesion after successfully healed AV-IE. At 1-year follow-up, the risk of IE relapse was low and mortality rate did not differ from TAVR patients free of prior IE, but one-fourth presented with significant aortic regurgitation and >50% required re-admission.