Incomplete surgical ligation of the left atrial appendage-time for a new look at an old problem

Different Techniques of Surgical Left Atrial Appendage Closure and Their Efficacy: A Systematic Review

Background

Atrial fibrillation has been identified as an independent risk factor for thromboembolic events. Since 1948 different surgical techniques have described the feasibility and the rationale of left atrial surgical appendage closure. The aim of this systematic review is to evaluate the reported patency rates of different surgical techniques.

Methods

This systematic review was conducted according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Two independent investigators searched the PubMed, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, and OVID® (Wolters Kluwer, Alphen aan den Rijn, Netherlands) to identify relevant studies. Consecutively, a PICO (Population, Intervention, Comparison and Outcomes) strategy assessment of literature was performed to search eventual other relevant studies that may have been ignored.

Results

A total of 42 studies were included in our analysis. The total number of patients who underwent surgical left atrial appendage closure was 5671, and in 61.2% an imaging follow up was performed, mostly with transesophageal echocardiographic evaluation. Success rate for the different techniques was: Clip deployment 98%; Lariat procedure 88%; Surgical amputation 91%; Endocardial suture 74.3%, Epicardial suture 65%; Left atrial appendage closure (LAAC) ligation 60.9%; Stapler technique with excision of left atrial appendage (LAA) 100%; Stapler without excision 70%.

Conclusions

To date, data on surgical left atrial appendage closure are poor and not standardized, even if reported rates are acceptable and comparable to transcatheter procedures. If validated on large-scale non-retrospective and multicentric studies, these promising developments may offer a valuable alternative for patients with atrial fibrillation (AF) and ineligible for oral anticoagulation therapy.

Left atrial appendage occlusion with Watchman device after incomplete surgical ligation

Non-valvular atrial fibrillation (NVAF) is the most common cause of cardioembolic stroke. The left atrial appendage (LAA) is the major source of cardiac emboli in patients with NVAF. Anticoagulation (AC) is the standard of care for stroke prevention in atrial fibrillation (AF), but many patients are intolerant of AC. Surgical exclusion of the LAA may result in incomplete closure and is associated with an increased risk of embolism. We report a case of a woman in her 50s with a history of persistent AF, mitral valve prolapse s/p repair with surgical LAA exclusion, and multifocal haemorrhagic stroke presented for elective LAA closure who underwent a Watchman placement successfully. This case demonstrates that a percutaneous approach for occlusion of the LAA when surgical exclusion was incomplete may be feasible with appropriate planning. Clinical outcome data for this patient group are needed.

Thermally responsive hydrogel for atrial fibrillation related stroke prevention

Atrial fibrillation induced stroke accounts for up to 15% of all strokes. These strokes are caused approximately 90% of the time by clot formation in the left atrial appendage (LAA). To prevent these clots, the most common approach is to administer blood thinners. However, contraindications prevent some people from being able to have blood thinners. Devices have been developed to seal the LAA to prevent clot formation in these patients. Current devices, such as the LARIAT® tie off the LAA theoretically preventing blood from entering the LAA. These have had limited clinical success mainly due to failure to completely close the LAA leaving holes and orifices for thrombi to form. To overcome this lack of complete closure, many surgeons use off-label approaches, classically filling the LAA filamentous coils, to cover these holes. Although this usually helps largely cover the holes, placement is challenging, the coils can migrate, the holes are not fully closed as there is space within and around the coils that don't fully mold to the LAA geometry. Furthermore, the coils can develop device related thrombi defeating their purpose. Therefore, these are not fully sufficient to complement the closure techniques in closing the LAA. To address limitation of the closure devices and coil sealing of remaining holes, we developed a thermally responsive hydrogel (Thermogel) that solidifies once injected into the LAA to uniformly and fully close off the LAA thus preventing clot formation and device related thrombi. This Thermogel consists of three portions: 1) a structural component composed of thiolated Pluronic F127 for gel to solid transition following injection, 2) Heparin for anticoagulation, and 3) Dopamine for adhesion to the surrounding endothelium in the turbulent flow encountered in cardiovascular applications. Here we have demonstrated that Thermogel, in conjunction with the LARIAT®, is capable of filling the defects in small and large animals through catheter injection. Thermogel was biocompatible and led to atrophy of the LAA at 5 weeks in a large animal model. Given the advantages of this Thermogel for sealing this defect and ability to be delivered through an endovascular approach, Thermogel presents a viable adjuvant to current occlusion-based treatments for sealing cardiovascular defects.

Surgical left atrial appendage closure: Success rate and its relationship with cerebrovascular accident

Background: Several surgical procedures such as excision or exclusion are recommended for the closure of the left atrial appendage (LAA). This study was conducted with the aim to evaluate the success rate of different surgical techniques for LAA closure, their respective complications, and the rate of post-surgical cerebrovascular accident (CVA). Methods: This retrospective study included 150 consecutive patients who underwent LAA closure most commonly after mitral valve surgery within 3 to 6 months after surgery. An expert echocardiographic fellow collected the data on patients' surgical LAA closure methods and history of CVA, types of prosthetic valves, mortality, and bleeding. Results: The failure rate for complete LAA closure was 36.7% (55 patients) in our study. The greatest success rate of complete LAA closure was seen in purse-string method (75.5%), followed by resection method (71.4%), while the lowest success rate (≈ 33.3%) was observed in ligation method. A significant relationship was observed between clots on the surface of metallic valve and postoperative CVA (P = 0.001; likelihood ratio: 32).In multivariate analysis, there was also no statistically significant relationship between partial LAA closure and the incidence of post-surgical CVA (P > 0.050). Conclusion: We observed the highest success rate of complete LAA closure in purse-string method followed by resection method. Interestingly, our results showed that despite the higher rate of residual LAA clot in cases of partial LAA closure, the occurrence of post-surgical CVA was mostly related to the presence of clots on the surface of metallic mitral prostheses rather than the presence of partial LAA closure.

Incidence and clinical relevance of left atrial appendage membranes: a new congenital heart disease?

AIMS

Left atrial appendage (LAA) membranes are rare congenital anomalies. Those involving the appendage orifice may obstruct its emptying flows, thus promoting blood stasis and clot formation. However, the epidemiology of LAA membranes has never been studied and a correlation with appendage thrombosis has never been proved. Very few case reports described LAA membranes, therefore, their frequency and clinical significance are not known. Moreover, their presence and degree are of crucial importance in planning LAA percutaneous closure, a procedure whose indication is evolving, and whether their presence can represent technical issues during the device implantation is not known. This study aimed to evaluate the incidence and the clinical significance of LAA membranes.

METHODS AND RESULTS

A population of 6030 consecutive transoesophageal echo (TOE) studies has been retrospectively reviewed in order to find those patients in whom an LAA membrane has been found. A literature research has been performed to review previous described cases. Among 6030 TOE cases, an LAA membrane has been described in 6 (prevalence of 1/1000). In one case, the membrane was associated to a severe LAA hypoplasia and in another case to an LAA thrombus (these represent the first cases ever described). All patients had an atrial fibrillation (AF) history and two were in AF during the TOE exam.

CONCLUSION

LAA membranes are rare congenital abnormalities occasionally discovered during a TOE exam, frequently in patients affected by AF. In half of the cases, they obstruct the LAA flow, thus theoretically pre-disposing to clot formation. They may be rarely associated to an appendage hypoplasia. During a TOE exam, cardiac imagers should always rule out their presence.

The cessation of oral anticoagulation following left atrial appendage surgery

Atrial fibrillation is associated with a significantly increased risk of stroke, and oral anticoagulation is the mainstay of preventative treatment. Scenarios arise where the risks of treatment with oral anticoagulation may outweigh the benefits, most commonly when there is an elevated risk of bleeding. Studies of percutaneous closure of the left atrial appendage have strongly implicated this structure in the etiology of stroke in atrial fibrillation, and provide some rationale for the discontinuation of oral anticoagulation following percutaneous closure device implantation. A common clinical concern is the safety of cessation of oral anticoagulation after surgical closure of the left atrial appendage in patients with a history of atrial fibrillation. Here, we review the evidence guiding this management decision and draw comparison with data on percutaneous closure.

Catheterization Laboratory: Structural Heart Disease, Devices, and Transcatheter Aortic Valve Replacement

The cardiac catheterization laboratory is advancing medicine by performing procedures on patients who would usually require sternotomy and cardiopulmonary bypass. These procedures are done percutaneously, allowing them to be performed on patients considered inoperable. Patients have compromised cardiovascular function or advanced age. An anesthesiologist is essential for these procedures in case of hemodynamic compromise. Interventionalists are becoming more familiar with transcatheter aortic valve replacement and the device has become smaller, both contributing to less complications. Left atrial occlusion and the endovascular edge-to-edge mitral valve repair devices were approved. Although these devices require general anesthesia, an invasive surgery and cardiopulmonary bypass machine are not necessary for deployment.

The clot thickens: an incompletely ligated left atrial appendage

Our patient presented with known mechanical mitral valve endocarditis documented by 2D transesophageal echocardiogram (TOE) from a recent hospitalization at an outside facility. On admission to our center, there was no prior knowledge of an incompletely ligated left atrial appendage (LAA) according to patient- or family-reported history, review of outside records or the outside facility’s 2D TOE report. A 3D TOE performed at our center to assess her pathology, since a month had passed from her prior hospitalization, revealed a LAA ligation with evidence of communication to the left atrium and with clot present in the appendage. This case report highlights the common finding of incomplete closure of the LAA following surgical ligation, thus making it inadequate for stroke prevention in patients with atrial fibrillation, and that 3D TOE plays a valuable role in assessing the durability of LAA ligation.