Treatment of mechanical valve thrombosis during pregnancy

Pregnant patients with mechanical valves require anticoagulation. The risk of bleeding and embryopathy associated with oral anticoagulation must be weighed against the risk of valve thrombosis. In the presence of a mechanical valve thrombosis, an appropriate treatment modality must be selected, as it is critical for the health of mother and fetus. In this review, we present a pregnant patient with mechanical valve thrombosis (MVT) who underwent thrombolytic therapy, subsequent anticoagulation according to available guidelines, and delivered a healthy baby at full term.     

Thrombolysis is superior to heparin for non-obstructive mitral mechanical valve thrombosis

BACKGROUND AND AIM OF THE STUDY: Non-obstructive prosthetic valve thrombosis (PVT) is a unique subset that features clinical presentation without heart failure, and may be asymptomatic. Thrombolysis has been accepted for obstructive PVT, but treatment strategies of non-obstructive PVT are controversial. This study compared the efficacy and safety of thrombolysis and heparin treatment in these patients. METHODS: Between 1993 and 1998, 20 consecutive patients were found by multiplane transesophageal echocardiography (TEE) to have non-obstructive PVT. TEE was performed for peripheral embolism in two patients, stroke or transient ischemic attack in six, stroke and fever in two, fever in one patient, as a routine postoperative examination in two patients, and for other reasons in seven. Patients were allocated to two groups: group I (n = 8) received streptokinase-mediated fibrinolysis; group II (n = 12) received intravenous heparin by infusion. Treatment was monitored using TEE. RESULTS: There was no difference between patient groups with regard to sex, age, type of prosthesis and time since operation, though anticoagulant status was more often inadequate in group II. By TEE, valve motion was normal in all patients. In group I, all thrombi were mobile and 5-13 mm in diameter; in group II, all thrombi but three were mobile and 3-18 mm in diameter. In group I, thrombolysis was successful in all patients, without complications, within 6-72 h. In group II, heparin treatment was successful in six patients in 3-32 days. In one patient, seven days' of unsuccessful heparin was followed by two months' successful coumarin therapy. Among five unsuccessful cases, the thrombus size increased in four (three became obstructive in 7-35 days); all four patients were switched to fibrinolysis, which was successful without complications in 12-60 h. The fifth patient developed a stroke after nine days of heparin treatment and was subsequently operated on. CONCLUSIONS: Non-obstructive PVT may be asymptomatic in one-third of patients. Thrombolysis is an efficient and safe treatment, and may be first-line therapy if there is no contraindication. Heparin treatment was successful in about one-half of our cases in the presence of sessile or small thrombi and inadequate anticoagulant status. In unsuccessful cases, thrombi became obstructive or caused stroke during heparin therapy, the adequate duration of which remains unclear.     

Delayed aortic dissection and valve thrombosis after transcatheter aortic valve implantation

We report a case of a 78‐year‐old female who presented with type A aortic dissection 22 months following transcatheter aortic valve implantation (TAVI). In addition, preoperative echocardiogram showed high gradients across the aortic prosthesis which was found to be thrombosed. At surgery, the intimal tear appeared to be non‐acute and anatomically related to the rim of the valve cage. The thrombosed valve was not replaced and the patient received anticoagulation therapy following surgery with significant improvement in valve gradients.     

Spontaneous native aortic valve thrombosis

Spontaneous thrombosis of a native aortic valve is an uncommon event that usually follows local trauma, such as cardiac surgery or left heart catheterization, or occurs as a complication of bacterial endocarditis. We report the case of a 65-year-old woman with a history of retinal artery occlusion and severe aortic valve stenosis, in whom transesophageal echocardiography revealed a mobile mass attached to the ventricular surface of the aortic valve. There was no evidence of any hypercoagulable state or infection process. Surgery was performed and a severely stenotic valve resected; a partially organized and firmly adherent free-floating thrombotic mass was observed on the ventricular surface of the aortic valve. Histologic examination demonstrated an organized thrombus. Eleven months after surgery the patient is doing well.     

Safety of coronary stenting with eptifibatide and ultra-low-dose heparin

With the advent of multiple potent antiplatelet and anticoagulation agents in percutaneous coronary intervention (PCI), the risk of bleeding complications has increased. The optimal dose of unfractionated heparin in this setting is unclear. This study was designed to determine the feasibility and safety of PCI with an ultra-low-dose weight-adjusted unfractionated heparin regimen (30 IU/kg bolus, maximum 3,000 IU) in combination with aspirin, clopidogrel, and eptifibatide. We enrolled 83 patients who underwent nonemergency PCI of native coronary arteries. At 30 days, all patients were free of the primary clinical outcomes defined as a composite of death, myocardial infarction, or repeat target vessel revascularization, and there were no major bleeding complications.     

Recurrent thrombosis of an aortic valve prosthesis in a pregnant woman. Treatment with urokinase

A 36 year old woman developed two thromboses on aortic valve prosthesis. The first thrombus at the 14th week of pregnancy was treated with urokinase (2,000 U/kg/h) plus heparin (700-1,000 U/h) over 24 hours and normal wing kinetics were obtained. The second thrombus developed at the 36 th week of pregnancy when the patient was receiving calciparin, and only transient improvement was obtained with similar doses of urokinase hourly over 72 hours. Progressive worsening resulted in higher doses (4,000 U/kg/h) being given without heparin and the thrombus then resolved. The use of urokinase for the first time in this indication allowed therefore, on two occasions and without hemorrhagic complications the cure of this recurrent thrombosis on aortic prosthesis, and the birth, by caesarean, of a healthy baby.     

Mechanolytic management of transcatheter aortic valve thrombosis

Data on the incidence, characteristics, and treatment of thrombosis of a transcatheter aortic valve implantation (TAVI) implant are scarce. We report a challenging case of a TAVI thrombosis occurring 6 months after the procedure. Initial anticoagulation using low-molecular-weight heparin followed by thrombolytic therapy failed to both relieve symptoms and alleviate thrombosis. However, the condition of the patient deteriorated rapidly, necessitating the use of balloon valvuloplasty followed by low-dose thrombolysis. The uniqueness of the case can be summarized as follows: (1) first report of balloon valvuloplasty to manage a case of TAVI thrombosis; (2) thrombolytic therapy after balloon valvuloplasty was successful to further reduce gradient from valve thrombosis.     

Successful percutaneous treatment of suspected embolic left main thrombosis in a patient with a mechanical aortic valve

Left main coronary artery thrombosis is a rare but potentially fatal phenomenon. We present the unusual case of total occlusion of the left main coronary artery suspected to be secondary to embolized thrombus from a patient's mechanical, prosthetic aortic valve resulting in an anterior wall ST elevation myocardial infarction and cardiogenic shock. The acute interventional management and review of literature of left main thrombosis is described.     

Transcatheter aortic valve implantation in patients with a mechanical mitral valve

Many patients with severe aortic stenosis never undergo surgical treatment for various reasons. Apart from the standard risks, some patients face an additional problem: their carrying of a mechanical mitral valve. In these patients, transcatheter aortic valve implantation is a therapeutic option. The literature contains only few reports of this procedure being performed (usually transapically) in such patients. This paper reports the cases of 3 patients with severe aortic stenosis, all carrying a mechanical mitral valve and at high surgical risk, all of whom were implanted by transcatheter aortic valve implantation with an Edwards aortic valve prosthesis. All procedures were successful with no complications encountered.Full English text available from: www.revespcardiol.org     

经导管主动脉瓣置换术后瓣膜血栓的研究进展

随着经导管主动脉瓣置换术适应证向外科手术中、低危人群拓展,经导管主动脉瓣置换术后瓣膜血栓逐渐引起人们的关注。瓣膜血栓形成的机制尚不明确。瓣膜血栓的预防、检测及治疗仍在探索阶段。本文将对瓣膜血栓的发生率及潜在机制、检测手段、临床表现、不良结局、预防及治疗等进行综述。     

Fulminant thrombosis of mechanical mitral valve prosthesis

In patients with prosthetic heart valves non-cardiac surgery may require temporary discontinuation of oral anticoagulation. Although the risk of valve related thromboembolic complications may generally be only slightly increased during the short perioperative period, in the presence of certain risk factors, replacement of oral anticoagulation with heparin is recommended. In the presented patient, unusually fulminant and finally fatal thrombosis of a mechanical mitral valve prosthesis developed within only 48 hours after non-cardiac surgery despite heparin treatment. The thrombosis was triggered by clinical conditions favouring a hypercoagulable state. This report dramatically shows that despite improvements in prosthetic heart valve design and in the management of anticoagulation, thrombosis remains one of the most dangerous complications after valve replacement with a mechanical prosthesis.


Keywords: complications; mitral valve; mechanical prosthesis; thrombosis     

Spontaneous thrombosis of a transcatheter aortic valve replacement-induced aortic root pseudoaneurysm

Aortic annulus rupture or aortic root perforation is a rare complication of transcatheter aortic valve replacement (TAVR), requiring emergent cardiac surgery and carrying a high intraoperative mortality. Few cases can be managed conservatively, provided a strict clinical follow-up. This study describes the case of a 78-year-old patient with a degenerated bicuspid aortic valve stenosis who presented with a late aortic root perforation following TAVR, which was successfully managed applying a “watchful waiting” approach. Cardiac computed tomography imaging played a pivotal role in the diagnosis and subsequent decision on treatment and clinical follow-up.     

Papillary fibroelastoma in association with thrombosis on a mechanical valve

A patient with a thrombosed mechanical valve underwent valve re-replacement during which a tumor of the left ventricular outflow tract with the typical macroscopic and microscopic characteristics of a papillary fibroelastoma was successfully removed surgically. The 60-year-old woman had undergone isolated mitral valve replacement with a St Jude Medical 29-mm valve for mitral regurgitation 15 years ago. The present admission was for investigation of dyspnea on exertion. Two-dimensional transthoracic echocardiography demonstrated a posteroseptal, pedunculated mass, measuring 1.3x1.0 cm, in the outflow tract of the left ventricle, mild mitral regurgitation and slight aortic stenosis.     

Treatment of left intraventricular thrombosis with low molecular weight heparin

Following the discovery of a left intra ventricular thrombus (LIVT), the classical approach consists of treatment with non-fractionated heparin (NFH) followed by oral anticoagulants. The use of NFH for this indication has only been evaluated in one open, non randomised study of 23 patients with no control group. Low molecular weight heparins (LMWH) have not been the object of any study although they are routinely used by certain teams. The objective of this study was to evaluate the feasibility of the use of LMWH in the treatment of left intra ventricular thrombus. This was an open, non randomised prospective study. All patients having a newly diagnosed LIVT between September 2000 and September 2002 were treated with enoxaparine (100 IU/kg twice daily) for an average duration of 13 days; replacement with fluindione was started on the fifth day. The progression of the LIVT was followed using twice weekly transthoracic echocardiography for 3 weeks. RESULTS: 19 LIVT were discovered in 2 years (13 complicating an anterior infarct and 6 with a dilated cardiomyopathy). The average area was between 2.64 +/- 0.41 cm2 and 0.43 +/- 0.21 cm2 (p < 0.0001). Thirteen out of 19 thrombi disappeared with treatment (68.5%). There was no thrombocytopenia or haemorrhage. One transient ischaemic attack was noted. CONCLUSION: This preliminary work shows that LMWH are well tolerated and effective to make a thrombus disappear or to reduce its size.     

Early non-obstructive thrombosis of mechanical mitral valve prostheses

Transoesophageal echocardiography has shown a high incidence on non-obstructive thrombosis after mitral valve replacement with a mechanical prosthesis. The unpredictable outcome and the period during which the complication arises make treatment difficult. The aim of this study was to assess the tolerance and efficacy of the association of long-term heparin and oral anticoagulation, as recommended in this indication. All patients undergoing mitral valve replacement with a mechanical prosthesis between June 1999 and July 2001 were systematically included and studied by transoesophageal echocardiography in the immediate postoperative period. Those with non-obstructive thrombosis at least 5 mm in size were treated by heparin and oral coagulation until the thrombus disappeared on transoesophageal echocardiography. One hundred and fourteen patients undergoing 120 mitral valve replacements (6 reoperations) underwent transoesophageal echocardiography and non-obstructive thrombi measuring at least 5 mm were found on 26 occasions (21.7%). The association of heparin and oral coagulation was maintained for 7 to 115 days (average 20 days). No thromboembolic or haemorrhagic complications and no deaths were observed during this period. Two patients were treated with danaparoid and oral anticoagulation because of heparin-induced thrombocytopenia before the diagnosis. None of the patients died during follow-up (average 49 months); there were 4 recurrent non-obstructive thromboses, three of which were complicated by thromboembolic events with no sequellae in the first 8 months, again treated effectively with the association of heparin and oral anticoagulants; two cerebral embolic events without sequellae were observed without a demonstrable non-obstructive thrombus on transoesophageal echocardiography. The authors conclude that the association of heparin and oral anticoagulants seems well tolerated and effective in this small population and this would justify a large scale clinical trial.     

Subclinical leaflet thrombosis following transcatheter aortic valve replacement

Since the inception of transcatheter aortic valve replacement (TAVR), there have been significant reductions in complications due to improvements of transcatheter heart valve (THV) designs and technologies. Given expanding TAVR applications, reducing complications further and better understanding THV durability has become a focus within the structural heart space. Recently, dedicated cardiac computed tomographic angiography (CTA) performed at 1 month post‐TAVR has identified subclinical leaflet thrombosis (SLT), with rates as high as 40%. From the SLT imaging hallmarks of hypoattenuated leaflet thickening (HALT) to hypoattenuation affecting motion (HAM), a postulated timeline of THV thrombosis advancing to clinical symptoms can be recognized. This review article focuses on leaflet thrombosis particularly following TAVR explaining the spectrum of this disease process, its diagnosis, current treatment options, and future directions in the field.