Reply to the Editor

Abstract

We appreciate the response of Drs Stöllberger, Schneider, and Finsterer to our work1Kamohara K. Popović Z.B. Daimon D.M. Martin M. Ootaki Y. Akiyama M. et al.Impact of left atrial appendage exclusion on left atrial function.J Thorac Cardiovasc Surg. 2007; 130: 1639-1644Abstract Full Text Full Text PDF Scopus (21) Google Scholar and thank them for their comments. Here are our responses to their specific questions:1The left atrial appendage (LAA) area was not included when measuring the left atrial (LA) area. Slight changes in LA area and volume measurements might be expected due to the effect of the LA body shape change caused by occlusion of the LAA orifice. However, we have not detected any statistically significant decreases in the LA area or volume after LAA exclusion.2Although we did not measure the size of the LAA in this series, we did measure it in a more recent series of 16 dogs. The width and thickness of the LAA orifice were 27.1 ± 4.8 mm (mean ± standard deviation) and 12.2 ± 4.3 mm, respectively. As indicated by relatively small standard deviations, there is not a great variation in the LAA size in dogs.3Although we did not measure natriuretic peptide levels in this series, we did measure atrial natriuretic peptide and B-type natriuretic peptide levels in a more recent series. There were no significant changes in atrial natriuretic peptide level (32 ± 20 pg/mL at baseline and 41 ± 34 pg/mL after 30 days, P = .60) or B-type natriuretic peptide level (always <5 pg/mL). We did not observe any weight gain caused by fluid retention.4The investigated dogs were all killed on the day of the terminal study. During our follow-up period, we did not observe any significant decrease in stroke volume.5The effects of LAA occlusion on hemodynamics in patients with heart disease and in atrial fibrillation have to be carefully investigated in the future. We disagree with their conclusion that hemodynamically LAA occlusion might even do harm and should therefore not be performed in patients with atrial fibrillation. There is no solid evidence to suggest that exclusion of the LAA in patients with atrial fibrillation does harm. In fact, there is good evidence suggestive to the contrary2Johnson W.D. Ganjoo A.K. Stone C.D. Srivyas R.C. Howard M. The left atrial appendage: our most lethal human attachment! Surgical implications.Eur J Cardiothorac Surg. 2000; 17: 718-722Crossref PubMed Scopus (218) Google Scholar, 3García-Fernández M.A. Pérez-David E. Quiles J. Peralta J. García-Rojas I. Bermejo J. et al.Role of the left atrial appendage obliteration in stroke reduction in patients with mitral valve prolapse: a transesophageal echocardiographic study.J Am Coll Cardiol. 2003; 42: 1253-1258Abstract Full Text Full Text PDF PubMed Scopus (264) Google Scholar; much of this has been gathered from patients undergoing mitral valve surgery or surgical ablation. However, it is also clear that surgical LAA ligation with current techniques and technology is sometimes incomplete. Such incomplete ligation might be responsible for an increased risk of thromboembolic events after attempted ligation.4Katz E.S. Tsiamtsiouris T. Applebaum R.M. Schwartzbard A. Tunick P.A. Kronzon I. Surgical left atrial appendage ligation is frequently incomplete: a transesophageal echocardiographic study.J Am Coll Cardiol. 2000; 36: 468-471Abstract Full Text Full Text PDF PubMed Scopus (293) Google Scholar Our focus is on the development of a method for reliable, complete, and simple occlusion of the LAA. With such an approach, we will have the ability to study the clinical effects of LAA exclusion. At this time, we believe that such effects have not been fully elucidated. Leave the left atrial appendage untouched for stroke prevention!The Journal of Thoracic and Cardiovascular SurgeryVol. 134Issue 2PreviewWe read the article by Kamohara and collesgues1 regarding the short-term and midterm effects of left atrial appendage (LAA) occlusion on left atrial (LA) function with great interest. An atrial exclusion device was applied by means of thoracotomy in 19 mongrel dogs in sinus rhythm, and hemodynamic, as well as echocardiographic, data were recorded immediately and after 7 and 90 days. The authors found that LAA exclusion might affect LA reservoir function. We would like to congratulate the authors for their important study. Full-Text PDF