Ann Thorac Surg 1995;60:1111-1112
© 1995 The Society of Thoracic Surgeons
Case Reports
Paradoxical Embolism in the Presence of Right-to-Left Shunt Due to Tricuspid Occlusion
Calin Vicol, MD,
Vladimir Danov, MD,
Eberhard Struck, MD
Department of Cardiac Surgery, Central Hospital Augsburg, Augsburg, Germany
Accepted for publication April 11, 1995.
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Abstract
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The case of a 33-year-old woman suffering from a paradoxical peripheral embolism in the presence of a right-to-left shunt at the level of an ostium secundum defect is presented. A functional stenosis of the tricuspid valve due to obstruction through a thrombotic atrial mass was found to be responsible for the right-to-left shunt. Treatment consisted of peripheral embolectomy, removal of the atrial mass, and closure of the atrial septum defect.
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Introduction
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Paradoxical embolism results from the transportation of embolic material into the peripheral arterial circulation through a connection between the venous and the arterial systems. In most cases this connection is a patent foramen ovale, and only in rare cases is it a ventricle septal defect or a persisting arterial duct. The question of the mechanism that enables the embolus to pass from the right heart into the left seems to be significant. Normally right atrial pressure values are only half the left atrial value. In the presence of an atrial septal defect blood flows from left to right. An inversion of these conditions may result from a chronic or acute increase in pressure in the pulmonary circulation. A chronic increase in pressure occurs after severe pulmonary stenosis, pulmonary hypertension of different origin, Ebstein's anomaly, isolated hypoplastic right ventricle, and tricuspid stenosis or atresia. An acute increase in pressure results from a massive pulmonary embolism. Even under normal conditions an acute transitory increase in right atrial pressure and, consequently, the outcome of a hemodynamically effective right-to-left shunt may be evoked by Valsalva's maneuver. In this situation a venous thrombus may pass through a patent foramen ovale [1]. An increase in right-to-left shunt as well as an increased risk of paradoxical embolism is observed in the presence of masses (thrombus or tumor) in the right atrium [2]. Obstructions in the tricuspid valve area, leading to an increase in pressure in the right atrium, due to a functional valve stenosis and a subsequent right-to-left shunt are rare. Obstruction materials may come from tumors [3] or thrombi [4]. Paradoxical embolisms as a consequence of this pathologic state are rare also [5].
A 33-year-old woman showing signs of acute ischemia of the left lower limb was received in the emergency room. An intracranial hemorrhage due to a ruptured aneurysm had been treated surgically 4 years ago. For 2 years the patient had been suffering from a chronical bronchitis. A progressive cyanosis had been recently diagnosed. The initial examination in our hospital showed a patient who seemed to be seriously ill, and generally in poor health. A marked cyanosis of the acra, dyspnea at rest, and tachypnea were observed. The investigation of the lungs and the heart did not reveal any pathologic findings except a diastolic murmur at the lower left sternal border. There was a rhythmic pulse of 100 beats/min. The patient was complaining of pain and a numb sensation in the left foot. Comparing both sides, there was a significantly delayed filling of the capillaries on the left side. The femoral pulse was not palpable. Concerning laboratory values, an increased hematocrit by 60% was striking. The hemoglobin content was significantly increased to 187 g/L. The electrocardiogram showed a sinus tachycardia of 108 beats/min, a left preponderance, and a widened P wave in terms of a left atrial dilatation; apart from these, the findings were normal. Chest radiograph and abdominal sonography did not show any pathologic findings. Angiography confirmed the suspected occlusion of the left iliac artery.
With these conditions a transfemoral embolectomy of the left side was performed. In doing so, thrombotic material could be removed from the iliac and femoral arteries. To clarify the marked cyanosis and the respiratory symptoms of suspected paradoxical embolism, we performed transthoracic and subsequent transesophageal echography 1 day postoperatively. A tumor of 4 x 5 cm was found in the right atrium, attached to the lateral wall and prolapsing into the tricuspid valve, in the presence of a high-grade functional tricuspid stenosis with a lumen of approximately 1 cm2. Additionally, an atrial septal defect with a marked right-to-left shunt was diagnosed (Fig 1
). For further clarification cardiac catheterization was performed, revealing the atrial septum defect already known with a marked right-to-left shunt. Oxygen saturation in the aorta was very low (65%). On the basis of the oxymetric data, a right-to-left shunt of 75% could be calculated. There was no pulmonary hypertension.
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Fig 1. . Pediculate mass of homogenous structure prolapsing through the tricuspid valve. (ASD = atrial septal defect; LA = left atrium; P = pedicle; RA = right atrium; RV = right ventricle; T = thrombus; TV = tricuspid valve.)
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As a result of these conditions, the indication for removal of the atrial mass and closure of the atrial septal defect was made. We performed this procedure after the cardiac catheterization. The operation was carried out using extracorporeal circulation and cardioplegic protection of the myocardium. On this occasion, a pediculate mass the size of a tangerine was removed from the right atrium. Histologic investigation revealed an organized thrombus. In the septum secundum area a defect 2 cm in diameter was found. The defect was directly closed. After operation, the patient did not complain of dyspnea anymore. The cyanosis disappeared immediately after the operation. The patient was discharged 34 days postoperatively after the infected (embolectomy) inguinal wound had healed. The follow-up carried out 3 months later showed good preliminary postoperative results; the clinical investigation did not reveal any pathologic findings.
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Comment
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Paradoxical embolism evoking cerebral and extremity ischemia have met with an increasing interest in recent years. This is due to the great number of cerebral infarctions [6] and acute peripheral ischemias [7] to be classified as embolic. Our case presents a functional tricuspid stenosis owing to a big thrombus prolapsing into the tricuspid valve. The pressure increase in the right atrium due to the tricuspid obstruction led to a right-to-left shunt at the level of the atrial septum defect, leading to a highly progressive cyanosis. The polyglobulism that had developed at the same time suggested that the shunt had become substantial. Under these conditions it resulted in a fragmentation of the thrombus and subsequent paradoxical peripheral embolism.
In the event of arterial embolism and concomitant cyanosis paradoxical embolism should be taken into consideration. A transesophageal echocardiography is the method of choice to diagnose masses in the right atrium. These patients have to undergo operation as soon as possible due to the risk of complete occlusion of the tricuspid valve, or fulminant pulmonary or cerebral embolism. Owing to the symptoms of ischemia of the extremity coming to the fore and their clinical importance, the symptoms of a right-to-left shunt are often overlooked. As a consequence of such a ``wrong diagnosis'' these patients are placed in an acute life-threatening condition.
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Footnotes
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Address reprint requests to Dr Vicol, Herzchirurgische Klinik, Zentralklinikum Augsburg, Stenglinstr 2, 86156 Augsburg, Germany.
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References
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- Langholz D, Louie EK, Konstadt SN, Rao TLK, Scanlon PJ. Transesophageal echocardiographic demonstration of distinct mechanisms for right to left shunting across a patent foramen ovale in the absence of pulmonary hypertension. J Am Coll Cardiol 1991;18:1112–7.[Abstract]
- Lee JJ, McKenzie FN, Novick R. Right atrial myxoma with cyanosis due to right-to-left shunting. Can J Cardiol 1990;6:262–4.[Medline]
- Grollier G, Montecot L, Galateau F, et al. Shunt droit-gauche secondaire a un sarcome de l'oreillette droite. Arch Mal Coeur 1990;83:1007–10.
- Singh A, Fein S, Daudiss K, Lombardo D, Biddle T. Passage of mobile right heart thrombus to the left cardiac chambers: echocardiographic detection and surgical removal. J Clin Ultrasound 1988;16:592–4.[Medline]
- Goldschlager A, Popper R, Goldschlager N, Gerbode F, Prozan G. Right atrial myxoma with right-to-left shunt and polycytemia presenting as congenital heart disease. Am J Cardiol 1972;30:82–6.[Medline]
- Hart RG. Cardiogenic embolism to the brain. Lancet 1992;339:589–94.[Medline]
- AbuRahma AF, Lucente FC, Boland JP. Paradoxical embolism: an under-estimated entity. J Cardiovasc Surg 1990;31:685–92.[Medline]
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Abstract
Introduction
