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Ann Thorac Surg 2006;81:1585-1586
© 2006 The Society of Thoracic Surgeons

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Original article: Cardiovascular

Invited commentary

Toronto General Hospital, Room EN 13-219, 200 Elizabeth St, Toronto, Ontario, Canada M5G 2C4

(Email: tirone.david{at}uhn.on.ca).

	Introduction

Top Introduction Online Discussion Forum References

 
In this article [1] the authors compared the outcomes of two techniques of implantation of aortic valve homograft for aortic valve replacement (AVR) (ie, aortic root replacement [RR] with aortic root preservation [RP]. They included the techniques of subcoronary implantation (with or without preservation of the noncoronary aortic sinus of the homograft) and aortic root inclusion under the same group. I do not know enough biostatistics to judge Grunkemeier's methodology for a meta-analysis on 11 nonrandomized clinical reports of such complex, varied, and heterogeneous patient population as AVR with aortic valve homograft. Most of those reports came from centers where the surgeons do not use aortic valve homograft routinely for AVR. Also important is the fact that the techniques of implantation of aortic valve homograft are highly variable among surgeons, and I question the appropriateness of including subcoronary implantation and aortic root inclusion into a same group. Actually, when implanted in appropriate patients using the correct technique, the aortic root inclusion is more like an aortic root replacement than a subcoronary implantation. Finally, certain patients can have only RR because of altered aortic root anatomy. The authors claim that they were able to overcome most of these problems by measuring the "heterogeneity" on the reports, something that I find almost impossible to quantify because most studies were retrospective analyses of clinical outcomes of completely different methods of acquisition of the database.

Having expressed my concerns about the methodology of this study, I have to say that I agree with the conclusions reached by the authors. In those 11 clinical reports, the overall operative mortality was 7% (50 of 846) for RR and 3.8% (63 of 1667) for RP. Although these mortality rates are obviously different, the authors concluded that they were not so because of the heterogeneity on clinical reports. This is obvious by reading those 11 reports used in the meta-analysis that no quantification is needed. Patients who had RR were usually sicker, had more complex aortic root pathology, and many had active infective endocarditis and aortic root abscess. Therefore one would expect a higher operative mortality in the RR group.

Although the duration and method of follow-up in the 11 clinical reports were highly variable, the authors concluded that RR was associated with a lower reoperation rate than RP. The heterogeneity score among the 11 reports was very low for reoperation. Operative mortality rate is a hard end-point, whereas reoperation rate is not. It is well known that freedom from reoperation is lower than freedom from failure of the homograft after AVR [2]. A hidden bias on reoperation rate after AVR with homograft is the fact that surgeons are more reluctant to take on a patient who had RR than RP. The mortality rate for reoperation after RR is known to be high and in one report it was 25% [3].

Undoubtedly, the technique of aortic root replacement with aortic valve homograft is simpler and more predictable than the subcoronary implantation. The aortic annulus, the aortic cusps, the aortic sinuses, and the sinotubular junction function as a unit, and replacing one or two parts of it is far more complex than the whole thing. Surgical expertise plays a major role in the outcome when the technique of subcoronary implantation is used, and it is further complicated by the difficulty in matching the patient's aortic root to that of the donor aortic cusps. Because most patients who need AVR have abnormal aortic root, implantation of a stentless valve in the subcoronary position remains a formidable technical challenge that is easily overcome intraoperatively, but it may still fail with time [4].

	Online Discussion Forum

Top Introduction Online Discussion Forum References

 
Each month, we select an article from the The Annals of Thoracic Surgery for discussion within the Surgeon's Forum of the CTSNet Discussion Forum Section. The articles chosen rotate among the six dilemma topics covered under the Surgeon's Forum, which include: General Thoracic Surgery, Adult Cardiac Surgery, Pediatric Cardiac Surgery, Cardiac Transplantation, Lung Transplantation, and Aortic and Vascular Surgery.

Once the article selected for discussion is published in the online version of The Annals, we will post a notice on the CTSNet home page ( http://www.ctsnet.org ) with a FREE LINK to the full-text article. Readers wishing to comment can post their own commentary in the discussion forum for that article, which will be informally moderated by The Annals Internet Editor. We encourage all surgeons to participate in this interesting exchange and to avail themselves of the other valuable features of the CTSNet Discussion Forum and Web site.

For May, the article chosen for discussion under the Adult Cardiac Dilemma Section of the Discussion forum is:

Midterm Results of the Edge-to-Edge Technique for Complex Mitral Valve Repair

Derek R. Brinster, MD, Daniel Unic, MD, Michael N. D'Ambra, MD, Nadia Nathan, MD, and Lawrence H. Cohn, MD

Tom R. Karl, MD

The Annals Internet Editor

UCSF Children's Hospital

Pediatric Cardiac Surgical Unit

505 Parnassus Ave, Room S-549

San Francisco, CA 94143-0118

Phone: (415) 476-3501

Fax: (212) 202-3622

e-mail: mailto:karlt{at}surgery.ucsf.edu

	References

Top Introduction Online Discussion Forum References

 

1. Athanasiou T, Jones C, Jin R, Grunkemeier GL, Ross DN. Homograft implantation techniques in the aortic positionto preserve or replace the aortic root?. Ann Thorac Surg 2006;81:1578-1586.[Abstract/Free Full Text]
2. Lund O, Chandrasekaran V, Grocott-Mason R, et al. Primary aortic valve replacement with allografts over twenty-five yearsvalve-related and procedure-related determinants of outcome. J Thorac Cardiovasc Surg 1999;117:77-91.[Abstract/Free Full Text]
3. Kaya A, Schepens MA, Morshuis WJ, Heijmen RH, Brutel de la Riviere A, Dossche KM. Valve-related events after aortic root replacement with cryopreserved aortic homografts Ann Thorac Surg 2005;79:1491-1495.[Abstract/Free Full Text]
4. David TE, Ivanov J, Eriksson MJ, Bos J, Feindel CM, Rakowski H. Dilation of the sinotubular junction causes aortic insufficiency after aortic valve replacement with the Toronto SPV bioprosthesis J Thorac Cardiovasc Surg 2001;122:929-934.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Tirone E. David Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by David, T. E. Search for Related Content PubMed PubMed Citation Articles by David, T. E. Related Collections Related Article