Cardiac myxoma following transcatheter closure of an atrial septal defect

Abstract

To date, no significant association has been reported between atrial septal defects (ASD) and cardiac myxomas. This study reports a 56-year-old woman with cardiac myxoma following transcatheter closure of ASD. She presented with a 3-month history of recurrent dizziness, vertigo, palpitations, and generalized weakness after undergoing ASD occlusion a year earlier. Echocardiography and cardiac computed tomography scans identified a large, mobile mass (7.2 cm × 2.8 cm) in the left atrium, protruding through the mitral valve. The patient underwent median sternotomy and pericardiotomy, and the histopathological examination confirmed the diagnosis of atrial myxoma. The current case illustrates the challenges in determining whether an atrial mass is a benign myxoma or a dangerous thrombus. While there is no definitive link between the implantation of an ASD closure device and the formation of a myxoma, the emergence of this tumor is a potential occurrence.

CASE SUMMARY

A 56-year-old woman presented at an outpatient clinic with a 3-month history of recurrent episodes of dizziness, vertigo, dyspnea upon moderate exertion, and palpitations. She also reported generalized weakness. She had a past medical history of insulin-dependent diabetes mellitus and hypertension. Two months prior to the presentation, the patient experienced an episode of elbow dislocation during a fainting spell. The dislocation was managed conservatively. She had also undergone transcatheter closure of a 25 mm atrial septal defect (ASD) with an Amplatzer Septal Occluder (size 30 mm) 2 years before the presentation. Additionally, coronary angiography had been performed at the same time. On physical examination, her blood pressure was 190/90 mm Hg, her heart rate was 120 beats/minute, and her temperature was 37 °C. Blood work revealed mild anemia and a slight elevation in blood urea levels. Her body measurements were as follows: weight 95 kg, height 175 cm, body surface area 2.18 m², and cardiac output 5.232 L/min.

Echocardiography demonstrated a normal left ventricular function without any clear hypokinetic areas. However, it revealed a large mobile mass, measuring 6.7 cm, attached to the posterior wall of a dilated left atrium. This mass was protruding through the mitral valve into the left ventricle and was associated with moderate mitral valve stenosis (Supplementary Video 1). Cardiac computed tomography (CT) with contrast corroborated these findings, showing an ill-defined hypodense lesion at the mitral valve area. The lesion, measuring 7.2 cm in length and 2.8 cm in width, was suspected to be a cardiac myxoma or a vegetation (Figure 1). Brain CT scan revealed multiple foci of diminutive density, each approximately 3 mm in size, located in the deep white matter. The carotid Doppler study indicated a mild, bilateral increase in the intimal wall thickness of both carotid arteries. However, the flow direction was found to be triphasic, and the systolic velocity fell within the normal range. A subsequent coronary angiogram was performed, which revealed a feeding branch (collateral) leading to a mass in the left atrium, situated near the Amplatzer Septal Occluder (Figure 2). Importantly, no critical lesions were detected in the coronary arteries.

Figure 1.

Cardiac computed tomography showing an ill-defined hypodense lesion at the mitral valve area.

Figure 2.

Coronary angiogram revealing a feeding branch (collateral) leading to a mass in the left atrium, near the Amplatzer Septal Occluder.

Upon the patient’s admission to the ward, a regimen of anticoagulants, specifically heparin infusion, was initiated. Additionally, beta-blockers were administered for rate control, alongside antihypertensive medications. The decision was made to perform median sternotomy and pericardiotomy for the patient under general anesthesia. Following the insertion of aortic and bicaval cannulas and cardioplegia, the Amplatzer Septal Occluder was carefully dissected and removed. The mass was also excised, and the inter-ASD was closed using a synthetic Dacron patch (Figure 3). The total cardiopulmonary bypass time was 81 minutes, and the cross-clamp time was 50 minutes. Gross examination of the excised specimen consisted of aggregated tissue pieces, collectively measuring 7 cm in size. The tissue appeared gray and brown, demonstrating a soft, fragile consistency with a gelatinous and glistening surface. Histological analysis revealed a large hemorrhagic region within hypocellular tissue. The tissue was characterized by myxoid and hyalinized components. Spindle cells were scattered throughout, accompanied by edema and vascular congestion. Additionally, foci of chronic inflammatory cell reaction were observed. These findings confirmed the diagnosis of an atrial myxoma (Figure 4).

Figure 3.

Intraoperative photo showing the Amplatzer Septal Occluder with the mass.

Figure 4.

Histological analysis shows hypocellular tissue, characterized by myxoid and hyalinized components. Spindle cells were scattered throughout, accompanied by edema and vascular congestion.

The patient had an uneventful postoperative course and was discharged on the fifth postoperative day, with scheduled follow-up appointments.

CLINICAL QUESTIONS

1. The differential diagnosis of cardiac masses found after interatrial septal occluder insertion for ASD can help to identify the underlying cause of the mass and determine the appropriate treatment plan. Which of the following should be considered in the differential diagnosis?

   1. Thrombus

   2. Infection

   3. Cardiac myxoma

   4. All of the above

2. Regarding surgical consideration of removal of a cardiac mass found in a patient who had a history of interatrial septal occluder insertion for ASD, which of the following statements are true?

   1. It is considered an urgent procedure, particularly if the patient had a history of embolism or syncope.

   2. A left atrial approach is difficult; a trans right atrial approach is preferred.

   3. Very large tumors may have to be removed piecemeal.

   4. All of the above.

Answers are provided at the end of the article.

DISCUSSION

The diagnosis and management of cardiac masses are fraught with complexities, often requiring a multimodal diagnostic approach and nuanced treatment strategies. Our case, a 56-year-old woman with a significant atrial mass, brings forth an uncommon but critical issue in cardiovascular medicine. This diagnostic dilemma—whether the atrial mass was a myxoma or a thrombus—is reminiscent of challenges highlighted in some other studies. For example, Ruge et al described a patient who developed a left atrial thrombus on an occlusion device used for patent foramen ovale closure, identified as the source of cerebral emboli 3 years postprocedure.¹ Additionally, Bac et al presented the case of a 62-year-old patient who developed a left atrial myxoma 2 years following successful ASD device occlusion, emphasizing the indispensable role of echocardiography in diagnosis and treatment planning.² Li et al reported a similar case of a 72-year-old patient who presented with previous ASD closure, exertional dyspnea, and hemoptysis, which was later found to be due to myxoma.³ Mastrangelo et al reported a case involving a 71-year-old man who was hospitalized for atrial fibrillation. He was found to have an ostium secundum ASD and was treated with a closure device. During follow-up, a mass was found attached to the closure device. Although initially suspected to be a thrombus, the mass was later confirmed to be a myxoma.⁴

Cardiac masses can have a range of origins: benign tumors, malignant tumors, or thrombi. Accurate diagnosis, therefore, necessitates a multifaceted imaging approach. For instance, cardiac myxoma on echocardiography shows slightly lobar and varied echodensity, typically movable, with or without a stalk. On CT, it presents with the absence of contrast enhancement, and potential calcification may be present. However, clots exhibit differently on echocardiography depending on the time; in the acute phase, they exhibit low echodensity, and in the chronic phase, they exhibit high echodensity. CT scan of clots reveals no enhancement with contrast agents, indicating a lack of perfusion.⁵ Advanced imaging techniques such as 3D echocardiography can further aid in ascertaining the mass’s tissue characterization and its potential hemodynamic impact.⁶ Li et al emphasized the role of both transthoracic and transesophageal echocardiography alongside CT angiography in providing a comprehensive view of the mass.³

Currently, transcatheter device closure of ASD type II is considered the preferred treatment approach.⁷ In a comprehensive study by Krumsdorf et al examining 1000 consecutive patients who underwent ASD type II device occlusion, transesophageal echocardiography was utilized for postprocedural evaluation at both 4-week and 6-month intervals. They concluded that the incidence of thrombus formation on closure devices is relatively low and that these thromboses often resolve spontaneously when treated with anticoagulation therapy.⁸ Understanding the pathological aspects is essential not only for definitive diagnosis but also for evaluating the risks of complications such as embolization or systemic dissemination.

Given that myxomas are often prone to embolize or cause obstruction, timely surgical intervention is crucial.⁹ Traditional surgical techniques like median sternotomy were employed in this case, but it’s essential to mention the emerging role of minimally invasive approaches such as robotic-assisted cardiac surgery, which have shown promising results.¹⁰ Special attention was given to the patient’s preexisting ASD occluder, a foreign body that poses risks of embolization and infection if not handled carefully during surgical procedures. The finding in the case by Li et al that the atrial mass and an associated pulmonary embolus were both identified as myxoma further complicates the clinical scenario.³ This raises questions about the role of anticoagulation therapy, especially considering that Krumsdorf et al found thromboses often resolve spontaneously when treated with anticoagulants.⁸

Following successful mass excision, postoperative care involved vigilant monitoring to detect any signs of complications like arrhythmias, embolization, or infection. The long-term prognosis for atrial myxomas is generally favorable following surgical excision, but there exists a nonnegligible risk of recurrence, emphasizing the need for regular follow-up imaging.¹¹

A point to be drawn from this case is the potential association of cardiac myxoma with transcatheter closure of ASD and the importance of echocardiography and follow-up for such patients in clinical practice, as more similar cases have been brought to attention recently in the scientific literature.^2–4 One plausible explanation is when the Amplatzer Septal Occluder device is inserted to close the ASD, the endothelialization that occurs over time may increase the rate of generation of a mass; although no clear relationship exists between the implantation of an ASD closure device and a myxoma, the development of this tumor is a possible occurrence. In addition, this case underscores the vital role of a multidisciplinary team involving cardiologists, cardiac surgeons, and radiologists in managing complex cardiovascular conditions. Furthermore, the patient’s coexisting comorbidities, such as diabetes mellitus and hypertension, necessitated an integrated approach to management to minimize perioperative risks.

In conclusion, our case enriches the medical literature on the complexity of diagnosing and managing cardiac masses, particularly in the presence of previous cardiac interventions like ASD closure devices. The advancements in imaging modalities and surgical techniques bring forth new horizons for patient care, although these also come with their own sets of challenges that require ongoing research and clinical acumen.

ANSWERS TO CLINICAL QUESTIONS

Question 1, d. (a) Thrombus formation is a known complication of interatrial septal occluder implantation. (b) Infection is another possible complication of interatrial septal occluder implantation. The incidence of infection after interatrial septal occluder implantation is 0.5%, and the most common causative organism is Staphylococcus aureus. Although the incidence of infection after interatrial septal occluder implantation is low, it is important to be aware of this potential complication and to monitor patients closely for signs of infection. (c) Even though there isn’t any direct information yet on the incidence of myxoma formation after interatrial septal occluder implantation, more cases are being reported in the literature regarding the possible association between these two entities.

Question 2, d. (a) Myxomas may obstruct pulmonary or systemic venous drainage or may impair flow across the atrioventricular valves, with the likelihood of these events greater with larger tumors. The obstruction is characteristically progressive. When obstruction is intermittent, syncope, often related to postural change, or sudden death may occur. This happens in less than one-fourth of patients with left atrial myxoma. (b) Because the stiffness of the interatrial septal occluder makes it difficult to retract the left atrium and put in a retractor, we should remove the septal occluder using a transseptal approach and close it with a synthetic surgical patch. (c) Very large tumors may have to be removed piecemeal, although every attempt is made to keep the tumor intact and to avoid tumor embolization.

Supplementary video

Echocardiography showing a large mobile mass, attached to the posterior wall of a dilated left atrium, protruding through the mitral valve into the left ventricle.

DISCLOSURE STATEMENT

All in control of content for this article report no financial relationships with ineligible companies. The authors report no funding. The patient consented to the publication of this report.