In this feature interview we speak with investigator and lead author of the EXCLUDE clinical trial, Gorav Ailawadi, MD, about the use of the AtriClip™ (AtriCure, Inc., West Chester, OH) for left atrial appendage exclusion. Dr. Gorav Ailawadi is an Assistant Professor of Surgery at the University of Virginia in Charlottesville, Virginia. Dr. Ailawadi recently presented initial results from the EXCLUDE trial at the 2011 American Association for Thoracic Surgery (AATS) meeting. In this article he also discusses his participation in the DEEP AF Feasibility Trial, which is evaluating the safety and efficacy of a dual epicardial/endocardial procedure (DEEP) for atrial fibrillation.
Describe the AtriClip Gillinov-Cosgrove LAA Exclusion System and how it works.
The AtriClip is a clip made of two parallel rigid titanium tubes with elastic nitinol springs covered with a knit-braided polyester sheath. The AtriClip is placed epicardially around the left atrial appendage and compresses the appendage at its base, excluding blood from entering the appendage. Animal studies have also documented that the appendage atrophies once the clip is placed.
Tell us about how the AtriClip is different from other LAA exclusion methods or products.
Other existing methods to remove the appendage involve suture ligation and stapler excision. However, suture methods often recanalize, leading to a higher risk of stroke in some studies. Stapler methods can also be dangerous, as the staple must compress the left atrial tissue to allow for closure with the potential for left atrial appendage tears or bleeding. Neither method is well suited for performance in a minimally invasive approach. Endocardial approaches, in which a device is transseptally delivered via a catheter, are under investigation. Preliminary studies from these trials suggest inadequate exclusion or procedural risks of stroke due to catheters in the appendage.1,2
Discuss the use of the AtriClip LAA Exclusion Device in the EXCLUDE trial. What EXCLUDE trial data was presented at the 2011 AATS annual meeting?
The EXCLUDE clinical trial (Exclusion of Left Atrial Appendage with AtriClip Exclusion Device in Patients Undergoing Concomitant Cardiac Surgery) was a nonrandomized, prospective multicenter IDE trial in the United States designed to assess the safety and efficacy of this novel clip. In this 71-patient, eight-center trial, the AtriClip was placed in adult patients undergoing elective coronary artery bypass grafting, valve surgery, or maze procedures with a history of atrial fibrillation or a CHADS score ≥2 via a median sternotomy. The trial demonstrated an excellent safety profile with no left atrial appendage injuries or bleeding. In addition, >95% of patients had successful exclusion of their appendage at CTA or TEE imaging at three-month follow-up.
In what other ways is the EXCLUDE trial significant?
The EXCLUDE trial is important because it supported the approval of the first surgical device specifically designed to surgically exclude the appendage and did so with zero complications and with an ability to treat 100% of those attempted.
Tell us about the recent FDA approval to use the device for minimally invasive surgical LAA exclusion for the totally thoracoscopic surgical portion of the FDA feasibility trial DEEP AF. What was the aim of the DEEP AF study?
Recently, the FDA approved the use of the AtriClip in the dual epicardial/endocardial procedure (DEEP) to treat atrial fibrillation. In the DEEP AF feasibility trial, atrial fibrillation patients without history of cardiac surgery are eligible for a combined/hybrid epicardial ablation via a totally thoracoscopic method and an endocardial ablation. This utilizes the strengths of both approaches. With the epicardial approach, lesions can be created extensively and efficiently, while the endocardial approach allows for excellent testing for gaps and mapping for other potential foci. During the procedure, the left atrial appendage is excluded. Traditionally, this has been performed using a stapler. However, this portion of the procedure can be dangerous due to appendage injuries. Therefore, the ability to use the AtriClip in this setting provides a much safer approach to performance of left atrial appendage exclusion.
Is enrollment for the DEEP AF trial complete? When will first results be available?
The enrollment for the DEEP trial is nearly half complete. The primary endpoint is atrial fibrillation at one year. We anticipate having results from this trial in 2012.
How could this investigational hybrid ablation procedure impact EP practices and the treatment of atrial fibrillation?
Certain populations of patients — specifically, patients with persistent or longstanding persistent atrial fibrillation — have poor outcomes with catheter ablation. Patients are seeking a more effective approach to treatment of their atrial fibrillation. The population of these patients in the U.S. is astronomical, and we have no good treatment option for these patients. A hybrid approach may lead to the most efficacious outcomes in these patients and provide an effective therapy.
Is there anything else you’d like to add?
The EXCLUDE trial efficacy endpoint was exclusion of the left atrial appendage at three months. Long-term studies are required to document a reduction in risk of stroke with the AtriClip or with any left atrial occlusion methods.
- Gillinov AM, Pettersson G, Cosgrove DM. Stapled excision of the left atrial appendage. J Thorac Cardiovasc Surg 2005;129:679–680.
- Kanderian AS, Gillinov AM, Pettersson GB, et al. Success of surgical left atrial appendage closure: Assessment by transesophageal echocardiography. J Am Coll Cardiol 2008;52:924–929.