Eur J Cardiothorac Surg 2009;35:747-748. doi:10.1016/j.ejcts.2008.12.031
Copyright © 2009, European Association for Cardio-thoracic Surgery. Published by Elsevier. All rights reserved.
Is the use of at least one internal thoracic artery (ITA) directly associated with increased long-term cardiac-specific survival?
Efstratios Apostolakisa,
Karolina Akinosogloub,*
a Department of Cardiothoracic Surgery, University Hospital of Patras, Patras, Greece
b Faculty of Natural Sciences and Medicine, Imperial College London, South Kensington Campus, Sir Alexander Fleming Building 6th Floor, SW7 2AZ London, UK
Received 6 October 2008;
accepted 19 December 2008.
* Corresponding author. (Email: k.akinosoglou07{at}imperial.ac.uk).
Key Words: CABG • Internal thoracic artery • Internal mammary artery • Bilateral internal thoracic arteries • Late survival • Comorbidity
Even though, the study by Mohammadi et al. [1] comes up with significant conclusions as to the use of at least one ITA (only as far as the late outcome is considered), it seems to be lacking the liability of a perspective randomized study.
Retrospective examination of results of a non-designed study suffers major flaws as the element of early outcome is absent. And it is these early outcomes that identify and strictly differ between the 3 subgroups of NITA, SITA or BITA patients and eventually determine the surgeon's decision. Clinical experience has shown that NITA subgroup of patients suffer from more severe coronary heart disease comparing to the other two (SITA and BITA) [2,3]. Specifically:
- (A) In the population of cardiac-death, sudden as well as unknown death is included. This inevitably bears a high index of error. A patient with chronic renal failure, who will most possibly suffer a sudden death (due to hyperkalemic arrest or pulmonary edema), will, according to the author's methodology, be falsely included in cardiac related death.
- (B) As shown by Fig. 1, late survival of 3 totally inconsistent groups is compared, as far as preoperational clinical findings are concerned (Table 1, data related to age, chronic renal failure severity, DM, COPD, etc.). As a result, a not so careful study of Fig. 1 will lead to the conclusion that NITA group has a worse survival rate comparing to the BITA one. Nevertheless, high comorbidity of the former group will still remain, and gradually get worse, even after the surgery. Which is actually the true rate of non-cardiac related death for all groups during their follow-up?
- (C) According to Table 2, it is concluded that SITA contrary to NITA, is not included in the predictors of long-term cardiac-death. The same thing is shown for BITA in comparison to SITA for some subgroups of ages, such as >65 years.
However, these patients usually suffer the highest incidence of comorbidity. Thus, it would be interesting to compare the perioperative data (as you did on the Table 1) for the patients above and under 65 years.
- (D) According to other studies [3,4], there seems to be no significant difference relation to the graft patency between vein or arterial grafts after the first 5 years postoperatively, where coronary vessels >2 mm diameter are concerned, combined with early administration of anti-coagulant factors. As a result, since survival directly depends on vessel permeability [2], survival curves in this study should be almost consistent with each other, especially since average follow-up is 5.7 ± 3.7 years. On the contrary, the latter is observed only for the SITA and BITA subgroups, but not the NITA, at least for the first 5 years. Should there perhaps be a survival subgrouping according to survival (1–5 years, 5–10 years and >10 years)?
Footnotes
The authors of the original paper [1] were invited to reply to this Letter to the Editor but they did not respond.
References
- Mohammadi S, Dagenais F, Doyle D, Mathieu P, Baillot R, Charboneau J, Perron J, Voisine P. Age cut-off for the loss of benefit from bilateral internal thoracic artery grafting. Eur J Cardiothorac Surg 2008;33:977-982.[Abstract/Free Full Text]
- Goldman S, Zadina K, Moritz T, Ovitt T, Sethi G, Copeland J, Thottapurathu L, Krasnicka B, Ellis N, Anderson R, Henderson W, the VA Cooperative Study Group Long-term patency of saphenous vein and left mammary artery grafts after coronary artery bypass surgery. JAAC 2004;44:2149-2156.
- Goldman S, Zadina K, Krasnicka B, Moritz T, Sethi G, Copeland J, Ovitt T, Henderson W, VA Cooperative Study Group #297 Predictors of graft patency 3 years after coronary artery bypass surgery. J Am Coll Cardiol 1997;29:1563-1568.[Abstract]
- Buxton B, Tatoulis J. Conduits for coronary surgery. In: Wheatley D, editor. Surgery of coronary artery disease. 2nd ed.. London: Arnold; 2003. pp. 266.
