Isolated Thrombus Producing Tricuspid Stenosis: An Unusual Presentation in Primary Antiphospholipid Syndrome

Saibal Mukhopadhyay, Satish Suryavanshi, Jamal Yusuf, Chandrashekhar,
Vishal Rastogi, Vijay Trehan, UA Kaul

Department of Cardiology, GB Pant Hospital, New Delhi

We report the case of a female patient who presented with signs and symptoms of tricuspid stenosis. Echocardiography revealed a sessile mass on the tricuspid valve. A diagnosis of primary cardiac tumor was made but histopathologic examination revealed the mass to be an organized thrombus. Subsequent serological tests showed elevated titers of anticardiolipin antibodies in the absence of any associated disease. This case highlights an unusual presentation of the primary antiphospholipid syndrome. (Indian Heart J 2004; 56: 61–63)  

Key Words: Thrombus, Tricuspid stenosis, Antiphospholipid syndrome

Tricuspid stenosis (TS) is almost always rheumatic in origin. Other rare reported causes of TS include right atrial tumor, carcinoid syndrome, vegetation on the tricuspid valve, and pacemaker lead. We report a case in which a sessile mass on the septal leaflet of the tricuspid valve detected by echocardiography was responsible for the signs and symptoms of TS. Although initially we had provisionally ascribed the mass to be a tumor,histopathologic examination, later, proved it to be an organized thrombus. Subsequent investigation for a hypercoagulable state revealed elevated titers of anticardiolipin antibodies in the absence of any associated disease. Thus, the patient was diagnosed as a case of primary antiphospholipid syndrome (PAPS) presenting with an intracardiac thrombus on the tricuspid valve producing TS.

Case Report

A 23-year-old unmarried female presented with a history of undue fatiguability, swelling over the feet and abdomen, decreased appetite, and pain in the right upper abdomen of 6 months duration. There was no history of prolonged fever or painful swelling of the limbs prior to the onset of symptoms. There was no history suggestive of recurrent arterial or venous thrombosis, and no clinical features of connective tissue disorders. There was also no history of any drug intake predisposing to a hypercoagulable state.

Physical examination revealed a pulse rate of 90/min, regular in rhythm, blood pressure of 100/70 mmHg, raised jugular venous pressure with a prominent "a" wave, and bilateral pitting edema of the lower limbs. Examination of the cardiovascular system revealed no abnormality except a grade II/VI mid-diastolic murmur best audible in the left lower parasternal area, which increased in intensity on inspiration. Per abdomen examination showed tender hepatomegaly along with ascites.  

On transthoracic echocardiography (TTE), the inferior vena cava appeared dilated, with minimal variation in the diameter with respiration, and presence of spontaneous echogenic contrast but no thrombus. The atrioventricular and semilunar valves were normal, but a well-defined sessile, hyperechoic mass with specks of calcification was seen on the atrial side of the septal leaflet of the tricuspid valve (Fig. 1). The mass measuring 3 cm×1.6 cm was prolapsing into the right ventricular cavity during diastole, and swinging back into the right atrium during systole. Color Doppler revealed a turbulent flow across the tricuspid valve in diastole with continuous-wave Doppler revealing an E/A ratio of <1 with an E-wave velocity of around 1.5 m/s, and calculated peak/mean gradient across the tricuspid valve of 16/8 mmHg.

As the site of the attachment of the mass was not clear on TTE, transesophageal echocardiography (TEE) was done. This showed the mass to be attached to the atrial surface of the tricuspid valve free from the atrial septum, which had a small (6 mm) ostium secundum atrial septal defect (ASD) (Fig. 2). No other mass was present in the atria, ventricles or pulmonary arteries, and the pericardium was normal. In view of the absence of any history suggestive of a hypercoagulable state predisposing to thrombus formation or of infective endocarditis, a probable diagnosis of a primary cardiac tumor was made, and the patient was referred for surgical removal of the tumor. At surgery, the mass was successfully removed without any damage to the underlying leaflet, and the ASD closed by direct suture. The patient had an uneventful recovery, and showed symptomatic improvement. But, to our surprise, histopathologic examination reported the mass to be an

organized fibrin thrombus with foci of calcification. So we undertook a detailed investigation to detect an underlying hypercoagulable state before initiating anticoagulant therapy.  

Hematology results were normal, apart from mild thrombocytopenia (platelet count 120×109/L). Bleeding time, prothrombin time, and activated partial thromboplastin time were normal. Tests for lupus anticoagulant, rheumatoid factor, antinuclear antibody, and antidouble-stranded DNA were negative. Tests for complement revealed normal C3, C4, and CH50 levels. Serum levels of homocysteine, proteins C and S, and antithrombin 3 were also normal. To rule out PAPS, sera were sent for assessing the levels of the anticardiolipin antibodies (ACLA), and the result showed raised levels of both IgG (24 µ/ml; normal <10 µ/ml) and IgM (14 µ/ml; normal <10 µ/ml) ACLA. Since the definitive diagnosis of PAPS requires demonstrating an elevated level of ACLA on two or more occasions at least 6 weeks apart, with the likelihood of a thrombotic complication occurring in the absence of other identifiable causes of a hypercoagulable state, a probable diagnosis of PAPS was made, and the patient put on a combination of aspirin (150 mg/day) and low-molecular weight heparin (5000 units/day) to prevent future formation of thrombi, as these patients often fail to respond to warfarin therapy. 

Discussion

The antiphospholipid syndrome (APS) is the most common acquired blood protein defect associated with either venous or arterial thrombosis or both, recurrent miscarriage, and thrombocytopenia in decreasing order of prevalence.1 The antibodies responsible for the pathologic manifestations are the lupus anticoagulant or the ALCA directed against the negatively charged phospholipids. Although initially detected in patients with systemic lupus erythematosus, 90% of patients who develop the antiphospholipid thrombosis syndrome are otherwise healthy individuals with no other associated medical illnesses—they are designated as having PAPS.2  

The cardiac pathology associated with PAPS includes valvular abnormalities and intracardiac thrombus. The valvular abnormality detected in up to 36% of patients with PAPS includes irregular thickening of the mitral and aortic valves, small vegetations < 10 mm in diameter on the atrial side of the valve along the line of leaflet coaptation, or both, resulting in mild valvular regurgitation.3 Histologic examination of these vegetations has revealed inflammation with cellular infiltration and fibrosis. Though thrombi have been reported in all four chambers of the heart in patients with PAPS, valvular thrombi are rare.4 Till now, there are only three case reports of thrombi developing on structurally normal valves in patients with PAPS—two on the mitral valve,5,6 and one on the tricuspid valve.7 The patients reported by Mottram et al.6 and Ebato et al.7 had presented with symptoms of cerebral embolism and pulmonary embolism, respectively, secondary to large mobile thrombi on the mitral and tricuspid valves detected subsequently by echocardiography. Nickele et al.5 described a fixed 1–2 cm thrombus adherent to the mitral valve mimicking a tumor (very similar to our patient) which, having a broad base, necessitated valve excision, and replacement with a prosthetic valve.  

The case reported here is interesting as the patient had an unusual presentation—features of tricuspid valve stenosis secondary to an isolated organized thrombus on the valve without any past evidence of venous or arterial thrombi. Such a presentation secondary to intracardiac thrombus in PAPS has not yet been reported in the world literature. Secondly, a diagnosis of PAPS with thrombotic complications is very important as warfarin is often ineffective in preventing future thrombus formation in this condition,3 although high-dose warfarin therapy (with high INR >3) is still considered a treatment option by many physicians. The current recommendation is to use a fixed dose of subcutaneous unfractionated heparin (approximately 5000 U every 12 hours), or a fixed dose of low-molecular weight heparin (approximately 5000 U every 24 hours), and aspirin or clopidogrel for at least 6 months after ALCA is persistently negative, when heparin therapy may be discontinued.

Correspondence: 

Dr Saibal Mukhopadhyay, 
Senior Research Associate,
Department of Cardiology,
GB Pant Hospital, 
New Delhi 110002.
e-mail: saibal_mukherjee@hotmail.com

References

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