Left Atrial Appendage Closure with the Watchman FLX System in a Patient with Hypertrophic Cardiomyopathy on Dialysis for End-stage Renal Failure

Abstract

Patients with hypertrophic cardiomyopathy (HCM) often have atrial fibrillation, and empiric anticoagulation is recommended in these patients, regardless of other risk factors. However, anticoagulation is not recommended for patients who require hemodialysis (HD) because of the high bleeding risk. We herein report a case of left atrial appendage closure (LAAC) using the Watchman FLX system for a dilated phase HCM patient complicated by persistent atrial fibrillation and requiring HD. LAAC with the Watchman FLX system may be an alternative to antithrombotic medications in patients with dilated HCM complicated by atrial fibrillation and requiring HD.

Introduction

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder, exhibiting remarkable genetic and clinical heterogeneity. Patients with HCM often have atrial fibrillation, and empiric anticoagulation is recommended in these patients, regardless of other risk factors, due to the unique embolic risk of stroke (1,2). Conversely, anticoagulation is not routinely recommended by global guidelines for patients who require hemodialysis (HD) due to the high bleeding risk (3). Furthermore, there is no consensus concerning the appropriateness of anticoagulation in patients with HCM complicated by atrial fibrillation and requiring HD.

Left atrial appendage closure (LAAC) has been noted as a safe alternative to anticoagulant therapy, and studies have shown its noninferiority to vitamin K antagonists (4). It has also been reported that LAAC can be performed safely and reliably in patients with HCM (5).

We herein report a case of LAAC performed with the Watchman FLX system (Boston Scientific, Marlborough, USA) for a dilated HCM patient complicated by atrial fibrillation and requiring HD.

Case Report

A 49-year-old man with hypertrophic cardiomyopathy developed atrial fibrillation and was referred to our hospital for anticoagulation therapy. He had received an implantable cardioverter defibrillator for primary prevention of sudden death due to HCM at 40 years old. He had always been a heavy drinker (130 g/day of alcohol) and recently fainted and suffered facial trauma after drinking.

Transthoracic echocardiography showed asymmetric hypertrophy; left ventricular end-diastolic and end-systolic dimensions of 46 and 42 mm, respectively; an ejection fraction of 39%; and a left atrial diameter of 59 mm, findings consistent with the dilated phase of HCM (D-HCM). Transesophageal echocardiography revealed no thrombus in the left atrium or left atrial appendage; however, spontaneous echo contrast (grade 3+) was observed. Left atrial appendage flow was 21.4 cm/s. Coronary computed tomography showed no coronary artery stenosis. According to a brain-heart conference (consisting of a cardiologist and neurologist), the patient had a high risk of stroke regardless of the CHADS₂ score (1 point: heart failure) and CHA₂DS₂-VASc score (1 point: heart failure) because of a dilated left atrium and dilated phase of HCM. He was also at high risk for bleeding based on the HAS-BLED score (2 points: abnormal renal function, alcohol), dialysis dependence, and risk of falls due to possible ventricular tachycardia. Our brain-heart team finally decided to perform LAAC instead of continuing anticoagulation therapy. We decided that he would not benefit from cardiac ablation or electrical cardioversion, considering the absence of palpitation and an enlarged left atrium.

LAAC was performed using the femoral vein approach with general anesthesia and transesophageal echocardiographic guidance. After transseptal puncture, a double-curved sheath was inserted into the left atrium. A 31-mm Watchman FLX system was selected based on the transesophageal echocardiographic measurements (Fig. 1). After confirming that the PASS criteria had been met to ensure procedural safety and efficacy, the device was deployed in the optimal position. The procedure was completed without complications, and the patient was discharged the following day. Antithrombotic therapy was administered based on the standard regimen (a combination of warfarin and aspirin for 45 days). Combination therapy was switched to aspirin and clopidogrel after transesophageal echocardiography at 45 days, confirming no obvious peridevice leak or left atrial thrombus (Fig. 2). From six months after LAAC, only aspirin was administered. Thereafter, no thrombotic events were detected. Two episodes of syncope and one fall with fracture were observed, but no significant bleeding events were noted.

Figure 1.

Diameter and depth of left atrial appendage on transesophageal echocardiography.

Figure 2.

Postoperative transesophageal echocardiography showing sealing of left atrial appendage with Watchman FLX. LA: left atrial, LAA: left atrial appendage

Discussion

The Watchman FLX system was able to be deployed safely and reliably, suggesting that LAAC can be an effective therapy for patients with dilated HCM complicated by atrial fibrillation and requiring HD.

LAAC can prevent thrombosis caused by atrial fibrillation without anticoagulation therapy. For HCM patients with atrial fibrillation, there is an increased risk of embolism regardless of other risk factors (1,2). In particular, patients with D-HCM have a larger left atrial diameter and a higher prevalence of atrial fibrillation than patients with dilated cardiomyopathy (DCM) (6). It has been reported that the risk of embolism rises with the increase in left atrial diameter (7). Compared with DCM, patients with D-HCM complicated by atrial fibrillation are a high-risk group for embolism, and anticoagulation therapy, such as vitamin K antagonists or direct oral anticoagulants, is necessary to prevent thrombosis; however, assessing the bleeding risk is crucial. In patients requiring HD, meta-analyses have shown that the risk of bleeding is increased with the administration of anticoagulation therapy (8). Mechanisms underlying increased bleeding risk in end-stage renal failure have been reported to be related to platelet dysfunction, coagulation system abnormalities, uremia, and uncontrolled hypertension (9). Globally, guidelines also suggest that anticoagulation should not be administered routinely (3). Thus, LAAC may be a very effective intervention in such cases where embolism prophylaxis is vital but, at the same time, anticoagulants are contraindicated due to the risk of bleeding.

LAAC with the Watchman FLX system is a safe alternative to anticoagulation medications. It has been reported to have similar results to vitamin K antagonists and to be a safe and effective alternative in primary and secondary stroke prevention in patients with HCM complicated by atrial fibrillation (4). A comparison of HD patients with atrial fibrillation who underwent LAAC and those who did and did not receive antithrombotic therapy showed a higher overall mortality in both the antithrombotic therapy group [hazard ratio (HR) 2.76 (95% confidence interval (CI) 1.31-5.86)] and the group not taking any antithrombotic therapy (HR 3.09 [95% CI 1.59-5.98]) than in patients undergoing LAA occlusion. This suggests that LAAC with the Watchman system is effective for patients with atrial fibrillation requiring HD (10). From a technical perspective, LAAC with the newest Watchman FLX device has been reported to be safer than that with conventional devices, allowing implantation at a shallower location in the LAA, with higher LAA coverage and lower device-related thrombosis (11). In the present case, LAAC was safely and successfully performed with the Watchman FLX system.

Patients with atrial fibrillation who have concomitant cardiomyopathy or require HD need to be carefully managed, including transcatheter interventions, despite risk scores for a better quality of life. A brain-heart conference is essential for making this decision. Particularly for patients with specific conditions in which the scoring system for predicting the risk of thrombosis/bleeding is ineffective, the intervention should be decided on a case-by case basis.

This is the first report of LAAC performed with the Watchman FLX system in a patient with dilated HCM complicated by atrial fibrillation and requiring HD. Although the best indication for LAAC remains controversial, LAAC is an attractive therapy for patients at high bleeding risk who require anticoagulation therapy. Following Watchman FLX, antiplatelet therapy should be instituted; if Watchman FLX allows for adequate closure of the left atrial appendage, in the future, antiplatelet therapy may also become minimized. LAAC would be more strongly considered in cases with a high risk of hemorrhaging. More studies with a larger number of patients are needed to establish definitive guidelines in this specific setting.

The authors state that they have no Conflict of Interest (COI).

Financial Support

This work was supported by a research grant from the Sakakibara Heart Institute.