The double ligation is achieved in three steps (Fig. 2).12 The first is to isolate the LAA and place a PDS II endoloop around the base, making sure to position the knot on the lateral aspect of the appendage. This way, the surgeon is able to engage and retain the endoloop on the medial aspect of the LAA. Next, the endoloop is tightened while making sure that the suture is tied without sliding it out of position. The suture is kept as low as possible, maximizing the amount of LAA excluded. It should be emphasized that caution in tightening the suture is imperative because excessive force could potentially injure the tissue. The endoloop has two purposes: first, to define the level of ligation, and second, to reduce the pressure within the LAA during the second stage of the technique. Next, a 4-0 polypropylene purse-string suture supported with multiple Teflon pledgets is placed slightly distal to the endoloop. This suture achieves complete exclusion of the appendage. Placement of the suture at this point can be accomplished without bleeding because the endoloop reduces the pressure in the LAA even when it is not completely occlusive. The four pledgets not only reinforce the closure and protect the atrial tissue but also, when these come together after tying, provide the surgeon initial tactile confirmation that the LAA has been completely ligated. Lastly, the LAA is opened to ensure complete ligation from the left atrium. We expect that by evacuating the appendage, the remaining atrial tissue will scar down. After evacuation, two large hemoclips are placed at the tip for safety. Further corroboration of complete ligation is achieved by immediate postoperative TEE assessment. A short video of the LLAA, Supplemental Digital Content 1, is available online at http://links.lww.com/INNOV/A35.
A follow-up TEE was done in 56 of the double ligation patients. Transesophageal echocardiography was performed by independent cardiologists for the following indications: precardioversion for arrhythmia (n = 32), to check valvular and cardiac function (n = 11), to explore for emboli/thrombi (n = 8), or to detect vegetation (n = 1). Other reasons include documenting an intracardiac shunt (n = 1) and ruling out tamponade (n = 1) and endocarditis (n = 2) (Table 2). The studies were performed on the Philips ie33 ultrasound machine (Koninklijke Philips Electronics N.V., Andover, MA USA). Evaluation of TEEs was performed by a single independent qualified echocardiographer. Studies used evaluated the LAA in multiple views, with color Doppler across the LAA to assess any residual flow into the appendage. Transesophageal echocardiography has long been used to investigate the blood flow of and detect thrombi in the LAA.13 The LAA was considered successfully ligated if its obliteration was observed on two-dimensional imaging, with no remnant stump greater than 1 cm remaining, and as long as absence of color flow by Doppler was also documented.
Overall, the ligated group had a higher rate of comorbidities. Despite this, the ligated group had a trend of less postoperative AF (19.4% vs 22.9%, P = 0.07) and an overall significantly lower in-hospital mortality (0.7% vs 3.0%, P < 0.001) and lower 30-day mortality (0.7% vs 3.4%, P < 0.0001) (Table 3). Of the 808 patients in the ligated group, 496 (61.4%) had off-pump surgery performed. There was a significantly higher incidence of reoperation for bleeding in the patients receiving the ligation on pump (5.1% vs 1.4%, P = 0.00). None of the re-explorations for bleeding involved the LAA as the source. Otherwise, there were no differences in surgical outcome based on performing the double ligation technique on or off pump.
There were 56 patients who underwent LAA ligation and had a TEE postoperatively (Table 2). The mean ± SD age of this subgroup was 70 ± 11 years. A total of 76.8% of these patients were men. Fifty-three (94.7%) of 56 closures were successful (Fig. 3), with three patients with persistent flow in the LAA. Although four patients showed remnant LAA, none of them had a remnant that exceeded a depth of 0.6 cm. Two (3.6%) of the 56 TEE patients had a CVA; however, neither of them had a remnant or Doppler flow into the LAA by TEE criteria.
The efficacy of LAA elimination has long been debated. This study represents the largest study since 2008 and includes contemporary patients. The safety of the technique is demonstrated by a low incidence of complications and significantly reduced rates of in-hospital and 30-day mortality, despite the fact that the ligated patients were sicker preoperatively. The subanalysis of the patients with follow-up TEE results revealed that double LAA ligation (LLAA) was successful in 94.7% of attempts. This figure is comparable with our previously established 96% (27/28) success rate of double ligation seen when using intraoperative TEE and postoperative transthoracic echocardiography using Definity (Bristol-Myers Squibb Medical Imaging, North Billerica, MA USA) contrast.12 The success of the double ligation technique is likely due to the fact that the endoloop precisely defines the base of the LAA, allowing for a very aggressive exclusion of most of the LAA tissue. This is reinforced by running the 4-0 Prolene suture above the loop. Final success is confirmed by opening the appendage, even during off-pump cases.
Complete ligation of the LAA using this combined technique has a much greater success rate than other surgical techniques. The reported success of LAA excision and suture exclusion is 73% and 23%, respectively.8 Prior studies have shown surgeon experience to be a significant factor in procedure success. Successful occlusion rates double after a surgeon has performed four cases.10 Our previous analysis demonstrated that the double ligation technique does not add significant time to the operation, taking only an additional 5 ± 3 minutes to perform.12 In addition, the results displayed in Table 4 indicate that the double ligation technique can be performed safely off pump, with comparable results with those patients receiving the procedure on pump.
The success rate of LAA closure found in our TEE subgroup suggests that most of the larger cohort had successful LAA exclusion. The overall incidence of CVA or TIA in the 1777 patients was found to be 1.3% (n = 23), approximately half of the national average.14 The frequency of CVA in the ligated group was half of that seen in the nonligated group, although this did not reach statistical significance in this series (0.7% vs 1.4%, P = 0.16). The ligated LAA could have contributed to this lower rate of permanent and transient stroke; however, it is important to stress that the causes of stroke are multifactorial and are well beyond the scope of this study. The frequency of stroke in the follow-up TEE subgroup is three times less than that reported in similar studies (3.6% vs 13%).8
Unsuccessful LAA occlusion could potentially have disastrous consequences. Thrombi have been shown to develop in 41% of partially closed LAA.8 This is believed to be the result of stagnant blood trapped in a partially closed appendage. However, the link between partial LAA ligation and increased risk for stroke has not been confirmed. Nevertheless, this theoretical risk combined with the prevalence of stroke in patients with ligated LAA suggests that patients who qualify should continue anticoagulation medication to provide the maximum protection from a CVA or TIA.
There are several devices designed to percutaneously occlude the LAA. The most commonly used is the WATCHMAN LAA occlusion device, which has been shown to have a successful implantation rate of 82%.4 In addition, the LARIAT device uses a catheter-based approach to successfully ligate the LAA in 96% of patients.15 Several devices are still in the early testing phase but have promising results.4,11 A 3-month follow-up of AtriClip, recently approved by the Food and Drug Administration, showed the device to successfully occlude the LAA in 67 (95.7%) of 70 patients.16 These three devices all have similar success rates to double ligation; however, these devices cost between $2000 (AtriClip) and $6600 (WATCHMAN) for a single device versus the cost of double ligation of $117.
This study has a few potential limitations. There may be a selection bias stemming from the fact that this was a retrospective study looking at patients with a TEE after LAA ligation. Because these patients required a TEE, these patients may be sicker than the rest of the population, as demonstrated by the higher incidence of stroke in the TEE group versus the entire ligated group (3.6% vs 0.82%). Multiple surgeons performed the surgeries, and this nonrandomized study does not account for the variability between surgeon skill, experience, and technique. This study aimed to show the safety and the success rate of the double ligation technique; therefore, the causes of CVA were not investigated. This study was conducted at a medium-sized, nonacademic hospital that serves a large, affluent population with the resources and the knowledge to maintain healthier lifestyles. These characteristics may infer an overall different experience than what may occur at a large academic or small community hospital.
Safe and reliable surgical ligation of the LAA can be achieved using the double ligation technique on and off pump. A subset analysis of patients with TEE follow-up demonstrated a 94.7% success rate, which is higher than any previously reported surgical method and is comparable with the highest percutaneous techniques. The double ligation technique also carries with it the added benefit of being relatively inexpensive compared with other modalities of LAA occlusion.
Double ligation was associated with lower incidences of stroke, bleeding complications, and myocardial infarctions as well as a trend for lower rates of AF than in nonligated patients 30 days after surgery. Interestingly, there were significantly lower rates of in-hospital and 30-day mortality in the patients receiving double ligation than those who did not. The high success rate, low cost, and low complication rate seen in this series suggest that the double ligation technique is a reliable, effective, and safe method of LLA ligation. Although stroke has a multifactorial etiology, successful LLAA removes one potential source of thrombi perioperatively and in the long-term.
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This is an interesting retrospective case series of 108 patients who underwent ligation of their left atrial appendage using a simple technique developed by the authors. In the 56 patients who underwent postoperative transesophageal echocardiography, the left atrial appendage was successfully occluded in 53 (95%) of patients. The authors noted a lower in-hospital and 30-day mortality in the ligated group, but this was likely due to selection basis and would need to be confirmed by a prospective trial.
This study suggests that the double ligation technique is able to successfully exclude the left atrial appendage. Further prospective studies are needed to determine whether this technique would be associated with any differences in late stroke or mortality. The low cost of this technique is attractive.
Left atrial appendage; Epicardial surgical technique; Transesophageal echocardiography; Atrial fibrillation
Supplemental Digital Content
©2013 by the International Society for Minimally Invasive Cardiothoracic Surgery