Right atrial appendage thrombus in a patient with a left atrial appendage occlusion device

Abstract

Management of right atrial appendage (RAA) thrombus is a clinical dilemma. We describe a case of incidentally found RAA thrombus in a patient with a left atrial appendage closure device (WATCHMAN). Options for the management of RAA thrombus include observation, anticoagulation, thrombolytics, or surgical extraction. Size, mobility, site of attachment of the thrombi, patient factors (e.g., bleeding risk), and other indications for anticoagulation may be used to guide management.

Management of right atrial thrombi is a clinical dilemma. Patients with suspected or proven right atrial thrombus are usually treated with anticoagulants, thrombolytics, or surgical thrombectomy, depending on thrombus morphology, risk of pulmonary thromboembolism, and patient-related factors (e.g., bleeding risk).^1–4 We describe a case of incidentally found right atrial appendage (RAA) thrombus in a patient with a left atrial appendage (LAA) occlusion device (WATCHMAN) and subsequent management.

CASE PRESENTATION

An 80-year-old man with known hyperlipidemia, type 2 diabetes mellitus, hypertension, coronary artery disease, chronic heart failure with reduced ejection fraction, permanent atrial fibrillation (AF), WATCHMAN device placement 8 months earlier, chronic kidney disease stage 3, and recurrent gastrointestinal bleeding episodes presented to the emergency department with dyspnea that had started 1 week earlier, as well as orthopnea, paroxysmal nocturnal dyspnea, and leg swelling bilaterally. His blood pressure was 162/103 mm Hg, pulse was 104 beats/minute, and oxygen saturation was 97% on 1 L oxygen by nasal cannula. His jugular vein was distended, a grade 3/6 holosystolic precordial murmur was audible, diffuse crackles were heard in all the lung fields, and ascites and pitting edema of the legs were present. His electrocardiogram showed atrial fibrillation without any acute ST/T wave changes. Chest radiograph was concerning for cardiomegaly and pulmonary edema. He was started on intravenous diuresis. Computed tomographic pulmonary angiography did not show any evidence of pulmonary embolism. A transthoracic echocardiogram showed a left ventricular ejection fraction of 25% to 30%. A transesophageal echocardiogram revealed a 3.4 × 1.7 cm thrombus in the RAA (Figure 1a). The LAA occlusion device was well seated with no significant peri-device leak (Figure 1b). Anticoagulation was held off during acute hospitalization. He was started on warfarin on a subsequent outpatient visit. The patient had finished the post-WATCHMAN warfarin course 7 months before the RAA thrombus discovery.

Figure 1.

(a) Transesophageal echocardiogram in midesophageal bicaval view with thrombus in the right atrial appendage (arrow). IVC indicates inferior vena cava; LA, left atrium; RA, right atrium; RAA, right atrial appendage; SVC, superior vena cava; TV, tricuspid valve. (b) Transesophageal echocardiogram three-dimensional image showing the left atrial appendage occlusion device.

The patient was seen in the clinic 9 days after discharge, and a shared decision was made to start anticoagulation. He did not have any further episodes of gastrointestinal bleeding or pulmonary embolism. Over the next few months, he had recurrent hospitalizations for heart failure exacerbations. He passed away 4 months later from a cardiac arrest, the etiology of which is likely from pulmonary edema secondary to heart failure exacerbation. An autopsy was not performed as per family wishes.

DISCUSSION

The WATCHMAN is an LAA occlusion device used in patients who have contraindications to anticoagulation and can allow the discontinuation of anticoagulation in such patients. Right heart thrombi often develop on injured endothelium, foreign bodies such as tumors, and indwelling devices.⁵ Intrinsically, they can be seen in AF and pulmonary hypertension.⁶ They are classified based on morphology. Type A thrombi are highly mobile, worm-like, can cross the tricuspid valve, and originate from the deep veins of the pelvis/legs. Type B thrombi are small and attached to the chamber wall and originate in association with structurally abnormal chambers or foreign bodies.¹ Among patients with AF, the reported range of incidence of RAA thrombus is 0.4% to 7.5%, and for LAA thrombus, 3% to 24%.⁷ Compared to the LAA, the RAA is shallower and does not exhibit remodeling with AF, which may explain the lower incidence of thrombus formation in the RAA.⁸ Type A thrombi have worse outcomes⁶ and are more likely to cause serious events like pulmonary embolism and cardiac dysfunction.

Management of RAA thrombi depends on thrombus morphology, presence/risk of pulmonary thromboembolism, and hemodynamic status. For Type A thrombus, thrombolytics or surgical thrombectomy is recommended, while Type B thrombi are managed with anticoagulation. Patient factors such as bleeding risk and hemodynamic instability are also used to guide management.^2–4

In conclusion, discontinuing anticoagulation is often a major motivation for patients to get LAA occlusion devices. However, thrombosis may occur at other sites and necessitate the resumption of anticoagulation. This may result in the futility of the LAA occlusion procedure. Such a scenario should always be discussed prior to the procedure.