Identification of right atrial thrombi using transoesophageal echocardiography

Acute transvenous pacemaker lead thrombosis early after implantation: A rare clinical scenario

Symptomatic thrombus formation due to a permanent pacemaker (PM) lead is a rare complication. It could be associated with serious outcome and should be suspected in patients who present with unexplained right heart failure, dyspnea, or syncope following dual-chamber PM implantation. A timely decision to perform an echocardiographic examination, followed by medical, thrombolytic, or surgical treatment can be necessary. We describe the case of an 84-year-old man who presented with syncope and hypotension a few days after PM implantation. A transesophageal echocardiography revealed a mobile mass in the right atrium attached to the pacemaker lead. Intravenous heparin allowed a complete resolution of the thrombus.

Right atrial pacemaker lead thrombosis causing tricuspid inflow obstruction

A 75-year-old man was admitted to our hospital with a complaint of progressive dyspnea with effort. The patient had a permanent pacemaker that was implanted 16 years ago. Transesophageal echocardiography revealed a large, mobile mass in the right atrium attaching to the insertion site of the atrial lead at the tricuspid valve level. Because of the size, mobility, and location of the mass, urgent surgical removal was considered. The mass was successfully removed. Histologic examination of the mass demonstrated a partially organized thrombus. The postoperative course was uneventful and the patient's symptoms improved remarkably after operation.

What to do with an atrial thrombus?

This case report is about an 84-year-old woman admitted with right atrial thrombus attached to a pacemaker lead, diagnosed by transesophageal echocardiography. Surgical treatment was rejected due to the high operative risk, and percutaneous stenting was performed with success; unfortunately, the outcome was fatal and the patient died. We review here the clinical features of right atrial thrombi, including the epidemiology, clinical manifestations, diagnosis, and treatment, which is sometimes controversial.

Treatment of right heart thromboemboli

BACKGROUND

The presence of right heart thromboemboli complicating pulmonary thromboemboli carries with it an increased mortality rate compared to pulmonary thromboemboli alone, but little is known about the optimal management of this difficult clinical situation. This fact is highlighted in the case study of a patient with a 19-cm right atrial thrombus complicating bilateral pulmonary thromboemboli.

STUDY OBJECTIVES

We sought to determine the effects of anticoagulation therapy, thrombolysis, and surgical embolectomy on mortality rate in patients with right heart thromboemboli.

DESIGN

Retrospective analysis of all reported cases in the English language literature (1966 to 2000) of right heart thromboembolism in which age, sex, therapy, and outcome were reported.

MEASUREMENTS AND RESULTS

We analyzed 177 cases of right heart thromboembolism. Pulmonary thromboembolism was present in 98% of the cases. The patients were evenly divided by gender with an average age of 59.8 years (SD, 16.6 years) years. Dyspnea (54.2%), chest pain (22.6%), and syncope (17.5%) were the most common presenting symptoms. The treatments administered were none (9%), anticoagulation therapy (35.0%), surgical procedure (35.6%), or thrombolytic therapy (19.8%). The overall mortality rate was 27.1%. The mortality rate associated with no therapy, anticoagulation therapy, surgical embolectomy, and thrombolysis was 100.0%, 28.6%, 23.8%, and 11.3%, respectively. Using multivariate modeling with survival as the primary outcome, age and gender were not associated with mortality rate, but thrombolytic therapy was associated with an improved survival rate (p < 0.05) when compared either to anticoagulation therapy or surgery.

CONCLUSION

The presence of right heart thromboemboli may have diagnostic and therapeutic implications in pulmonary thromboembolism patients. A well-designed prospective, randomized trial is needed to determine the optimal treatment of right heart thromboemboli.

Atrial thrombus and central venous dialysis catheters

A native arteriovenous fistula is the first choice for hemodialysis access. Despite improved catheter designs and the use of internal jugular veins, thrombotic complications still occur when tunneled central venous catheters are used as an alternative. Although right atrial thrombus (RAT) is a well-characterized complication of long-term central venous cannulation, particularly when used for parenteral nutrition and chemotherapy in pediatric practice, only 9 reported cases previously have been associated with the long-term use of central venous catheters for hemodialysis. We report five cases of RAT seen at our unit between 1994 and 1998 in patients who had been dialyzed using tunneled catheters. In four of five cases, the diagnosis was made during the investigation of hemoptysis or dyspnea. In the fifth case, a screening transthoracic echocardiogram revealed the thrombus. Three of five of the patients suffered pulmonary emboli, and a fourth patient had an unexplained electromechanical dissociation cardiac arrest without definite evidence of pulmonary embolus. Our experience suggests that anticoagulated patients with RAT remain at risk of pulmonary embolism. One of our patients successfully underwent atrial thrombectomy. In four of five of our cases and four of nine cases in the literature, the central venous catheter tip was within the right atrium. Positioning of the central venous catheter tip low down in the superior vena cava or in the right atrium has been advocated to improve dialysis adequacy and to reduce the incidence of catheter thrombosis. However, placement of the catheter tip within the right atrium may be associated with an increased risk of RAT.

The role of transesophageal echocardiography in the diagnosis and treatment of right atrial thrombi

Twenty patients with right atrial thrombi were identified through the use of transthoracic and transesophageal echocardiography. Transesophageal echocardiography identified right atrial thrombi in all 20 cases. Transthoracic echocardiography showed definite thrombi in only 6 (30%) cases and suggested thrombus in another 2 (10%) patients. Thus transthoracic echocardiography results were false-negative for right atrial thrombus in 60% of cases. All 3 thrombi found within the right atrial appendage and 2 of 3 thrombi on pacemaker wires were missed by transthoracic echocardiography. There was no significant difference in the mean size between those thrombi seen (1.37 +/- 0.6 cm) and those missed (1.5 +/- 0.9 cm) by transthoracic echocardiography. Transesophageal echocardiography also significantly affected treatment. Anticoagulation was initiated or amplified in 13 patients. In 8 of these 13, thrombi were seen only by transesophageal echocardiography. Surgery was performed to remove thrombi in 7 cases, and in 3 (43%) cases it was because of thrombi seen only by transesophageal echocardiography. This study suggests that transesophageal echocardiography should be performed whenever right atrial thrombi are suspected. Transesophageal echocardiography has a significant effect on the diagnosis and management of patients with right atrial thrombi.