• „ Original article

Long-term outcomes in patients after left atrial appendage occlusion: The results from the LAAO SILESIA registry

13rd Department of Cardiology, Silesian Center for Heart Diseases, Zabrze, Poland

2Department of Cardiology, Congenital Heart Diseases and Electrotherapy, Division of Medical Sciences in Zabrze, Medical University of Silesia, Zabrze, Poland

3Department of Cardiology and Structural Heart Diseases, 3rd Division of Cardiology, Medical University of Silesia, Katowice, Poland

43rd Department of Cardiology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, Katowice, Poland

5Department of Biostatistics, School of Health Sciences in Bytom, Medical University of Silesia, Katowice, Poland

ABSTRACT Background: The benefits of oral anticoagulation (OAC) therapy are undeniable. However, such treatment is contraindicated in 2%–10% of patients. According to the latest guidelines, percutaneous left atrial appendage occlusion (LAAO) may be considered in stroke prevention. Aims: We analyzed the data of patients from the Polish population, who had undergone LAAO procedures in the Silesian Province based on limited reports. Methods: The data from the SILCARD database of all patients who underwent LAAO between 2006 and 2019, and the data from the databases of the centers performing the procedures in the Silesian Province were included in the LAAO SILESIA registry. We analyzed the efficacy and safety of the procedure and its relationship with the occurrence of stroke and bleeding in the post-hospital follow-up. Results: We analyzed 649 patients with the mean values of CHA2DS2-VASc and HAS-BLED scores of 4.1 and 3.2, respectively. The predominant indication for LAAO was a history of bleeding during OAC. The most frequent in-hospital major adverse cardiac events were anemia, which required blood transfusion (5.5%), and pericardial effusion, which was treated either conservatively (0.9%) or interventionally (1.2%). During hospitalization, stroke was detected in 4 patients and three patients died of any cause. LAAO reduced the annual risk of stroke by 84% and the annual risk of bleeding by 27%. Conclusions: Based on a “real-life” cohort of patients from the Silesian Province, we concluded that LAAO is related to low in-hospital major cardiovascular adverse events. In the long-term follow-up, LAAO reduced the rates of stroke and bleeding. Key words: atrial fibrillation, left atrial appendage occlusion, stroke

INTRODUCTION

Atrial fibrillation (AF) is the predominant cardiac arrhythmia whose prevalence increases with age. In addition to clinical symptoms, a diagnosis of AF is associated with a higher risk of stroke and a poorer prognosis [1, 2]. Many papers and study results demonstrate that anticoagulant therapy is effective in reducing the risk of ischemic stroke and overall mortality in patients with AF [3, 4]. Although the benefits of oral anticoagulation (OAC) therapy are undeniable, such treatment is contraindicated in 2%–10% of patients [5, 6]. In the light of the above, according to the latest guidelines of the European Society of Cardiology (ESC) and the 2016 and 2020 guidelines of the Polish Cardiac Society, percutaneous left atrial appendage occlusion (LAAO) may be considered in stroke prevention [3, 4].

Since the introduction of the first LAAO procedures in the early 2000s, clinical experience and knowledge in this field have increased [7–9]. Various studies have shown that LAAO is associated with good short- and mid-term results regardless of the type of device used [8, 10–17].

Among these studies, the analyses based on patient data from the Polish population are limited. This prompted us to analyze patients undergoing LAAO in the Silesian Province using the unique methodology of the SILCARD registry completed with data from centers performing such procedures. The specific aim of our study was to analyze the efficacy and safety of the procedure and its relationship with the occurrence of stroke and bleeding in the post-hospital follow-up in a “real-life” cohort of patients.

METHODS

Data source

The data utilized in our registry were collected as part of the Silesian Cardiovascular Database (SILCARD) (ClinicalTrials.gov identifier, NCT02 743 533; https://clinicaltrials.gov/ct2/show/NCT02743533). General information on SILCARD was previously reported [18]. Briefly, the database contains records from all hospitals (n = 310) in the Silesian Province, which is a large administrative region in southern Poland with a population of 4.57 million people (approximately 12% of the total population of Poland), including 3.80 million adults. The Silesian Province provides a well-developed hospital network with two tertiary cardiology hospitals, three cardiac surgery departments, and 20 catheterization laboratories. The National Health Fund (NHF), which is the only public health care provider in Poland, has supplied all data to the database since 2006. The inclusion criteria were as follows: each hospitalization in the departments of cardiology, cardiac surgery, diabetology, or vascular surgery and hospitalization with a cardiovascular diagnosis in the department of internal medicine or intensive care. The exclusion criteria were hospitalizations of patients living outside of the Silesian Province and patients younger than 18 years on admission. The collected data included information on initial hospitalization with a diagnosis of cardiovascular disease (CVD) with a potential transfer to another department or hospital, other hospitalizations, and data from outpatient visits. If the patient was rehospitalized for CVD within 24 hours, both hospitalizations were considered one admission. According to the applicable rules, hospitals are obliged to report to the NHF on the principal diagnosis with up to two comorbidities defined by the International Classification of Disease, 10th Revision (ICD-10), and on medical procedures defined by the ICD-9 classification. CVD was defined as R52, J96, or any “I” code based on the ICD-10. The hospital registry number and the national identification number (PESEL) were used to match the information on each patient. All data were anonymized. The SILCARD registry was approved by the local Bioethics Committee.

The selected parameters of baseline characteristics and in-hospital course were completed from the databases of the centers performing the procedures (Silesian Center for Heart Diseases in Zabrze; Upper-Silesian Medical Center in Katowice; American Heart of Poland — Medical Center in Bielsko-Biała).

Study population

The analysis included all patients from the SILCARD database from January 1, 2006 to December 31, 2019 with atrial flutter or atrial fibrillation coded according to the ICD-10 as I48 who underwent percutaneous LAAO with the principal procedure coded according to the ICD-9 (international classification system for surgical, diagnostic, and therapeutic procedures, 9th Revision) as 37.4901. The exclusion criteria included residency outside of the Silesian Province and age under 18 years at the time of LAAO. As a result, the patient registry became known as the LAAO SILESIA.

Study data

Data available from the NHF included the total number of patients who had undergone percutaneous LAAO, their sex, age, comorbidities, hospitalization, and mortality. Screening for comorbidities was performed in hospital settings. Data were reported to the NHF using the ICD-10 and ICD-9 codes as primary or coexisting diagnoses. For the study, variables were defined as indicated in Table 1. Based on these baseline characteristics, stroke risk was calculated using the CHA2DS2-VASc clinical risk scale.

From the databases of the centers performing the procedures, the additional detailed in-hospital data were included (1) the major bleeding risk score according to the HASBLED score; (2) a history of bleeding during oral anticoagulation therapy without a reversible cause; (3) periprocedural successful implant deployment; and (4) the anti-platelet/anti-thrombotic drugs at the discharge.

The following follow-up data were collected: (1) bleeding, including the need for blood transfusion; (2) transient ischemic attack (TIA), stroke, including fatal and non-fatal stroke; (3) systemic embolism; and (4) all-cause mortality.

Statistical analysis

Continuous variables were summarized using the arithmetic mean with standard deviation (SD) for normal distribution or the median with interquartile range (IQR) for non-normal distribution. Normality of distribution was verified using the Shapiro-Wilk test. Categorical variables were summarized using frequency tables.

The event-free survival probability (stroke and bleeding) after discharge was presented using the Kaplan-Meier method. The time to occurrence of the event (i.e. stroke and bleeding) was calculated after the discharge. If the events did not occur until February 1, 2020, this date was considered the end of the follow-up for all patients.

The patient annual risk of stroke was recorded based on the subject’s CHA2DS2-VASc score, and then the average risk score for the study population was calculated. The annual risk of stroke and bleeding was then extrapolated from the published literature [19] and related to risk score estimation to determine the influence of LAAO on risk reduction in the analyzed group.

The calculations were performed using STATISTICA PL version 10 (StatSoft, Inc., Tulsa, OK, US).

RESULTS

The group we analyzed, included 649 patients. The number of procedures per year reached 25 in 2011, 6 in 2012, 8 in 2013, 62 in 2014, 71 in 2015, 92 in 2016, 116 in 2017, 124 in 2018, and 145 in 2019. The following number of LAAO procedures was performed per center in the analyzed period: (1) Silesian Center for Heart Diseases in Zabrze — 325; (2) Upper-Silesian Medical Center in Katowice — 208; (3) American Heart of Poland — Medical Center in Bielsko-Biała — 116.

Baseline characteristics

The mean (SD) age of patients eligible for LAAO was 73 (8) years. The mean (SD) values of CHA2DS2-VASc and HAS-BLED scores were 4.1 (1.9) and 3.2 (1.0), respectively. A history of bleeding on OAC without a reversible cause was the main indication for the LAAO procedure (81% of patients). In 17% of patients, a contraindication to OAC therapy was listed as an indication for LAAO. However, it was not specified. In addition, the ineffectiveness of long-term optimal anticoagulation in 9 patients and hematological disorders in 3 patients were reported. In most patients, chronic coronary syndrome, chronic heart failure, and hypertension were diagnosed. Baseline characteristics are listed in Table 2.

In-hospital course

The deployment of the occluder was successfully performed in 99.1% of patients. Postprocedural dual anti-platelet therapy with aspirin and clopidogrel was the primary treatment. Table 3 shows other important in-hospital course data, including the in-hospital need for blood transfusion in 36 patients (5.5%).

In 8 patients, interventional or surgical treatment was necessary due to pericardial effusion, and stroke was reported in 4 patients. Two adverse events were reported in 3 patients, whereas 3 adverse events were observed in one patient during an in-hospital stay. In a 71-year-old female, pericardiocentesis followed by surgical treatment was necessary due to periprocedural tamponade. During hospitalization, 3 patients died of any cause. Pericardial effusion and multiorgan failure leading to death were observed in a 74-year-old male on day 29 after LAAO. On the first day after the procedure, a 77-year-old female died due to a stroke. After successful surgical removal of the occluder directly after LAAO in a 51-year-old female, multiorgan failure developed, which resulted in the patient’s death on the same day.

Follow-up data

In a long-term follow-up with a median (interquartile range, [IQR]) of 777 (339–1324) days, TIA was diagnosed in 9 (1.4%) patients and stroke in 14 (2.2%) patients, including one subject who died due to a stroke. Among patients with stroke, 13 subjects were diagnosed with ischemic stroke and 1 with hemorrhagic stroke. Bleeding was reported in 25 patients (3.9%), including 9 patients (1.4%) who required blood transfusion. Systemic embolism was observed in 4 patients.

In a 12-month follow-up, ischemic stroke was reported in 5 patients (0.8%), whereas bleeding in 14 patients (2.2%). Considering the above and based on CHA2DS2-Vasc and HASBLED scores, LAAO reduced the annual risk of stroke by 84% and the annual risk of bleeding by 27% (Figure 2). Among the group of patients discharged from the hospital, 132 (20.4%) subjects died of any cause in the long-term follow-up (Table 4).

DISCUSSION

The presented data of patients who underwent percutaneous LAAO were obtained from a large regional registry. We analyzed baseline characteristics, selected in-hospital and long-term follow-up parameters, and information related to adverse events and death of any cause. Based on the results, we can presume that LAAO is safe and is associated with promising long-term efficacy to prevent stroke in AF patients with poor compliance to OAC.

LAAO was performed mainly in elderly patients (mean age, 73 years) with a high risk of stroke estimated by the CHA2DS2-Vasc scale — 4.1 (1.9). Both outcomes were similar to most results obtained from available registries [12, 16, 20, 21]. In a few registries, such as in the multicenter Amplatzer Cardiac Plug (ACP) registry [11], the mean age of patients who underwent the procedure was even higher, and the percentage of patients >75 years of age constituted 55% of the group. In addition, patients were usually affected by multiple diseases, including chronic coronary syndrome, chronic heart failure, and hypertension. Compared to the above registries, a significant difference in the collected data was related to a high percentage of heart failure (42.2%) and a proportionally low percentage of patients with chronic kidney disease (8.3%). It can be related to an increasing number of patients with heart failure in the Polish population [22] or the exclusion of this group of patients from the previous analyses [8, 10, 23, 24]. The obtained results may also be affected by the registry restriction, arising from a limited number of diagnoses reported to the NHF.

Notably, the predominant indication for LAAO in the Silesian population was bleeding related to OAC, which was reported in 80.9% of cases (including the incidence rates of hemorrhage or hemorrhagic shock, hemorrhagic stroke, or ocular hemorrhage). These indications are consistent with the consensus document prepared by the Association of Cardiovascular Interventions and the Heart Rhythm Section of the Polish Cardiac Society [25]. It is a rather high percentage compared to other European registries, where bleeding was the indication for LAAO in 42%–80% of patients [11, 16, 17, 20, 21]. These discrepancies are even greater when compared with the results of the analyses based on German registries. In the prospective LAARGE [17] registry, the frequency of major bleeding was low and occurred in 28.9% (bleeding was defined as severe in the case of transfusions, surgical treatment, intracranial hemorrhage, and/or hemodynamically unstable patients requiring urgent medical support) and was even lower (18%) in a study based on a single-center registry published by Kleinecke et al. [26]. Therefore, it may suggest that more different indications for LAAO are considered in the above-mentioned countries.

Interestingly, the percentage of successful implant deployment during LAAO was high and reached 99.1% in our population. The high percentage of successful implantations was previously reported [7, 10], and it increased with the experience of operators. Their expertise has an impact on the reduction of adverse events [8], particularly pericardial effusion and the need for blood transfusion. These data were confirmed by the Italian registry [27]. In our observation, the in-hospital prevalence of pericardial effusion depending on the treatment strategy (conservative or interventional) affected 6 (0.9%) and 8 (1.2%) patients, respectively. This percentage of pericardial effusion is comparable to the previous data from the ACP registry [11] where tamponade was diagnosed in 1.24% of patients or in the LAARGE registry [17] where pericardial effusion requiring intervention was reported in 2.3% of cases.

Interpretation of the comparative analysis of bleeding is difficult due to the dissimilarity of selected definitions of major bleeding for each study. In our analysis, the major bleeding was defined as the in-hospital need for blood transfusion and affected 36 patients (5.5%). The LAARGE prospective registry [17] reported the incidence of major in-hospital bleeding at 1.1% (seven patients). On the other hand, in the EWOLUTION registry [12], major bleeding occurred in 11% of patients within 30 days of the procedure.

Unfortunately, 3 patients (0.5%) died in the in-hospital period in the analyzed group. Two patients developed multiorgan failure after interventional treatment of peri­cardial effusion, and another patient died of a stroke. The risk of in-hospital death related to LAAO was low in the available registry data and ranged between 0.2% and 0.7% [12, 17, 20, 21]. In the ACP registry [11], three periprocedural deaths were reported. They were due to intracranial bleeding, cardiac tamponade, and embolization with a device, respectively. Other deaths occurred postoperatively due to arrhythmia, cardiac tamponade leading to multiorgan failure, an acute ST-elevation myocardial infarction (STEMI), device embolization on day 6 after the procedure, and pneumonia. In turn, Betts et al. [16] reported one death related to pericardial tamponade after transseptal puncture and advancement of the delivery sheath into the LAA. In the EWOLUTION registry [12]and long-term patient outcomes, including bleeding and incidence of stroke/transient ischemic attack (TIA) three deaths were reported, none of which was directly related to the procedure (right ventricular failure on the day of the procedure, respiratory insufficiency on day 4, and cardiac death on day 6 postoperatively).

The possibility for cessation of OAC without increasing thromboembolic complications is the essence of the LAAO procedure. In our database, in a long-term follow-up of 777 days, TIA and stroke occurred in 9 (1.4%) and 14 patients (2.2%), respectively. Bleeding was reported in 25 patients (3.9%), 9 (1.4%) of whom required blood transfusion (Figure 1).

Based on the above findings, an 84% reduction in the incidence of ischemic stroke and a 27% reduction in the incidence of bleeding were observed compared to the estimated value [19] (Figure 2). As we mentioned above, a detailed comparison of the prevalence of TIA, stroke, and bleeding episodes is problematic due to differences in reporting methods [11, 14, 17, 20, 21, 28]. However, the confirmed reduction of the occurrence of these adverse events should be indicated. The above registries report the annual risk of stroke after LAAO at 1.2%–2.2% [17, 20, 21, 28] ranging from 0.9% (ACP registry) [11] during a 13-month follow-up to 4.2% (Korean study) [14] during a 21.9-month follow-up. In large registries, the annual risk of major bleeding was estimated at 0.4-2.0% [17, 21, 28]. In turn, in the analysis of Kleinecke et al. [26], bleeding with varying degrees of severity occurred in 8 patients, which constituted 16% of the observed group.

In our cohort of patients, after a median follow-up of 777 days, more than 20% of patients died of any cause. This percentage seems to be high. As we mentioned above, patients undergoing LAAO represented the elderly Silesian population, often with many comorbidities that increase the risk of death. Compared to the international registries, the percentage of deaths increased with a higher mean age of patients and ranged from 5.2% during a 21.9-month follow-up to 11.5% during a one-year follow-up of the prospective registry [14, 17, 29]. Notably, the risk of death was independent of the type of occluder used for LAAO [21].

Limitations of the study

The above analysis was retrospective, with the typical limitations of this method. The LAAO-SILESIA registry based on the electronic database of a single healthcare provider is limited to core variables, coded according to ICD-9 and ICD-10, such as demographic data, comorbidities, in-hospital events (need for blood transfusion, TIA/stroke, in-hospital death, pericardial effusion depends on the method of treatment) and major cardiac events in a follow-up (death, bleeding, TIA/stroke). It does not cover data on laboratory results, echocardiographic parameters, fluoroscopy data, or the cause of death during the follow-up, which represents a major limitation of the study. The quality of data may be challenged by differences in the quality of data reported by different centers. The study does not account for patients who moved to another Province.

CONCLUSIONS

Based on a “real-life” cohort of patients from the Silesian Province, we conclude as follows:

The LAAO procedure is related to low in-hospital major adverse cardiac events.

LAAO reduced the rates of stroke and bleeding in a long-term follow-up.

Article information

Conflict of interest: None declared.

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