Edmilson Cardoso dos Santos FilhoI; Fernando Ribeiro de Moraes NetoII; Ricardo Augusto Machado e SilvaIII; Carlos Roberto Ribeiro de MoraesIV
DOI: 10.1590/S0102-76382009000200011
ABSTRACT
Objective: To assess, by scintillography, the effect of using bilateral internal thoracic arteries (BITAs) - prepared by two different techniques - on the sternal perfusion. Method: 35 patients undergone coronary artery bypass grafting (CABG) were divided into two groups: Group A (18) had both ITA's dissected using skeletonization technique and group B (17) as pedicle preparation. There was no difference in the two groups relating gender, age and demographic characteristics. On the 7th postoperative day the patients underwent bone scintillography. The statistical analysis was performed using the Student's t test with 95% significance. Results: Group A (skeletonized ITA) showed higher perfusion (11.5%) of the sternum as a mean, than Group B (pedicled ITA) patients; however this was not statistically significant (P = 0.127). On the other hand, comparing the diabetic population, seven in each group, there was a marked 47.4% higher perfusion of the sternum in Group A patients (skeletonized ITA) comparing to Group B (pedicled ITA) and this difference reached statistical significance (P = 0.004). Conclusions: 1- Sternal perfusion is not affected significantly apart from the dissection technique used for both internal thoracic arteries in the general population when assessed by bone scintillography. 2 - In the diabetic subgroup, a significant preservation of the sternal perfusion was observed in patients undergone skeletonized dissection of the internal thoracic arteries. Although these findings should be confirmed in a greater number of cases, diabetic patients should have the internal thoracic arteries dissected using skeletonization techinque.RESUMO
OBJETIVO: Avaliar o impacto na vascularização do esterno, por cintilografia óssea, da utilização de ambas as artérias torácicas internas (ATIs), preparadas por duas técnicas diferentes. MÉTODOS: Trinta e cinco pacientes coronarianos foram divididos em dois grupos: Grupo A - 18 pacientes tiveram as duas ATIs dissecadas de forma esqueletizada; Grupo B - 17 pacientes tiveram as duas ATIs dissecadas pela técnica pediculada. Não houve diferença nos dois grupos com relação a gênero, idade e características demográficas. Realizou-se cintilografia óssea 7 dias após a cirurgia. A análise estatística foi realizada utilizando-se o teste de t de Student. com significância estabelecida em 95%. RESULTADOS: No grupo A (ATI esqueletizada), o nível de captação do esterno foi de 11,5% mais alto em comparação com a média dos 17 pacientes do grupo B (ATI pediculada), mas essa diferença não foi estatisticamente significante (P = 0,127). Entretanto, a média dos níveis de captação do esterno nos sete pacientes diabéticos do Grupo A (ATI esqueletizada) foi 47,4% mais alta em comparação à média dos sete pacientes diabéticos do grupo B (ATI pediculada), e esta diferença foi estatisticamente significante (P = 0,004). CONCLUSÃO: 1- A forma de dissecção das ATIs não altera de maneira estatisticamente significativa a perfusão esternal, avaliada por cintilografia óssea, no conjunto geral da população estudada. 2- No subgrupo de pacientes diabéticos, observou-se melhor perfusão do esterno nos pacientes submetidos à dissecção esqueletizada. Embora a confirmação desse achado num maior número de casos seja necessária, pacientes diabéticos devem ter as artérias torácicas internas dissecadas de forma esqueletizada.INTRODUCTION
The use of two internal thoracic arteries (ITA) in coronary artery bypass grafting seems to result in better survival and reduced need for late reoperation [1-4]. However, this technique is not yet performed as a current practice, by arguing that the use of ITA would be associated with more morbidity, increased need for hemotransfusion [5], increasing probability of transoperative myocardial infarction [6] and, in particular, sternal osteomyelitis [7-10].
A retrospective study, analyzing a series of 2,594 patients undergoing CABG, showed, among other factors, the use of ITAs as a major risk factor for sternal infection [9]. A prospective, non-randomized study, in a series of 2,356 patients, identified through multivariate analysis, as a risk factor for sternal infection, the use of ITAs in the presence of diabetes mellitus [7].
An anatomic study suggested that the dissection of ITAs could lead to complete devascularization of the sternum [11], which would provide greater incidence of infections, especially in diabetic patients.
The dissection of internal thoracic artery (ITA) in a skeletonized manner, described by Keeley [12] in 1987, consisted of only obtaining the artery, without the adjacent tissues. This proposal aimed at the possible solution to problems associated with the use of ITA, such as low blood flow [13], improper length of the graft [14] and infection of the sternum [15,16], as observed recently in our country [17].
The study of sternal perfusion after dissection of the ITA, both through a pediculated or skeletonized technique, has already been object of several experimental studies [18,19] and clinical trials through the bone scintigraphy [20-22]. However, some results are conflicting.
The use of bone scintigraphy to assess the perfusion of the sternum was performed initially by purely visual analysis of the uptake of radioactive tracer [20]. After, it was established a quantitative analysis, by comparing the uptake of radioactive tracer by the sternum with another bone structure chosen as reference [23]. Other studies used the same principle for the evaluation of sternal perfusion, but using different methods [21,22,24].
This study was designed to assess the impact on sternal vascularization, by bone scintigraphy, of the use of ITAs dissected by two different techniques: pedicled and skeletonized. The study was performed in coronary patients and those with diabetes mellitus were not excluded.
METHODS
In the period between June 2005 and July 2006, 566 patients underwent CABG surgery at the Heart Institute of Pernambuco (Real Hospital Português de Beneficência in Pernambuco). Of these, 35 were prospectively selected for this study by establishing the following inclusion criteria:
1. Patients of both genders, aged less than or equal to 18 years with symptoms of stable angina and angiographic diagnosis of obstructions in at least two branches of the left coronary artery with indication for surgical treatment;
2. Patients with severe left ventricular dysfunction;
3. First heart surgery;
4. Patients who did not need associated procedures.
The 35 patients were divided into two groups:
REFERENCES
1. Puig LB, França Neto L, Rati M, Ramires JA, da Luz PL, Pileggi F, et al. A technique of anastomosis of the right internal mammary artery to the circumflex artery and its branchs. Ann Thorac Surg. 1984;38(5):533-4. [MedLine]
2. Lytle BW, Blackstone EH, Loop FD, Houghtaling PL, Arnold JH, Akhrass R, et al. Two internal thoracic artery grafts are better than one. J Thorac Cardiovasc Surg. 1999;117(5):855-72. [MedLine]
3. Lytle BW, Blackstone EH, Sabik JF, Houghtaling P, Loop FD, Cosgrove DM. The effect of bilateral internal thoracic artery grafting on survival during 20 postoperative years. Ann Thorac Surg. 2004;78(6):2005-12.
4. Taggart DP, D'Amico R, Altman DG. Effect of arterial revascularisation on survival: a systematic review of studies comparing bilateral and single internal mammary arteries. Lancet. 2001;358(9285):870-5. [MedLine]
5. Cosgrove DM, Lytle BW, Loop FD, Taylor PC, Stewart RW, Gill CC, et al. Does bilateral internal mammary artery grafting increase surgical risk? J Thorac Cardiovasc Surg. 1988;95(5):850-6. [MedLine]
6. Buxton BF, Tatoulis J, McNeil JJ, Fuller JA. Internal mammary artery grafting: is this a benign procedure? J Cardiovasc Surg (Torino). 1988;29(6):633-8. [MedLine]
7. Tavolacci MP, Merle V, Josset V, Bouchart F, Litzler PY, Tabley A, et al. Mediastinitis after coronary artery bypass graft surgery: influence of the mammary grafting for diabetic patients. J Hosp Infect. 2003;55(1):21-5. [MedLine]
8. Lepelletier D, Perron S, Bizouarn P, Caillon J, Drugeon H, Michaud JL, et al. Surgical-site infection after cardiac surgery: incidence, microbiology, and risk factors. Infect Control Hosp Epidemiol. 2005;26(5):466-72. [MedLine]
9. Diez C, Koch D, Kuss O, Silber RE, Friedrich I, Boergermann J. Risk factors for mediastinitis after cardiac surgery: a retrospective analysis of 1700 patients. J Cardiothorac Surg. 2007;2:23. [MedLine]
10. Pevni D, Mohr R, Lev-Run O, Locer C, Paz Y, Kramer A, et al. Influence of bilateral skeletonized harvesting on occurrence of deep sternal wound infection in 1,000 consecutive patients undergoing bilateral internal thoracic artery grafting. Ann Surg. 2003;237(2):277-80. [MedLine]
11. Arnold M. The surgical anatomy of sternal blood supply. J Thorac Cardiovasc Surg. 1972;64(4):596-610. [MedLine]
12. Keeley SB. The skeletonized internal mammary artery. Ann Thorac Surg. 1987;44(3):324-5. [MedLine]
13. Takami Y, Ina H. Effects of skeletonization on intraoperative flow and anastomosis diameter of internal thoracic arteries in coronary artery bypass grafting. Ann Thorac Surg. 2002;73(5):1441-5. [MedLine]
14. Deja MA, Wo's S, Golba KS, Zurek P, Domaradzki W, Bachowski R, et al. Intraoperative and laboratory evaluation of skeletonized versus pedicled internal thoracic artery. Ann Thorac Surg. 1999;68(6):2164-8. [MedLine]
15. De Paulis R, de Notaris S, Scaffa R, Nardella S, Zeitani J, Del Giudice C, et al. The effect of bilateral internal thoracic artery harvesting on superficial and deep sternal infection: the role of skeletonization. J Thorac Cardiovasc Surg. 2005;129(3):536-43. [MedLine]
16. Peterson MD, Borger MA, Rao V, Peniston CM, Feindel CM. Skeletonization of bilateral internal thoracic artery gafts lowers the risk of sternal infection in patients with diabetes. J Thorac Cardiovasc Surg. 2003;126(5):1314-9. [MedLine]
17. Milani R, Brofman PR, Guimarães M, Barboza L, Tchaick RM, Meister Filho H, et al. Dupla artéria torácica esqueletizada versus convencional na revascularização do miocárdio sem CEC em diabéticos. Rev Bras Cir Cardiovasc. 2008;23(3):351-7. [MedLine] View article
18. Parish MA, Asai T, Grossi EA, Esposito E, Galloway AC, Colvin SB, et al. The effects of different techniques of internal mammary artery harvesting on sternal blood flow. J Thorac Cardiovasc Surg. 1992;104(5):1303-7. [MedLine]
19. Fokin AA, Robicsek F, Masters TN, Fokin A Jr, Reames MK, Anderson JE Jr. Sternal nourishment in various conditions of vascularization. Ann Thorac Surg. 2005;79(4):1352-7. [MedLine]
20. Carrier M, Grégoire J, Tronc F, Cartier R, Leclerc Y, Pelletier LC. Effect of internal mammary artery dissection on sternal vascularization. Ann Thorac Surg. 1992;53(1):115-9. [MedLine]
21. Cohen AJ, Lockman J, Loberboym M, Bder O, Cohen N, Medalion B, et al. Assessment of sternal vascularity with single photon emission computed tomography after harvesting of the internal thoracic artery. J Thorac Cardiovasc Surg. 1999;118(3):496-502. [MedLine]
22. Korbmacher B, Schmitt HH, Bauer G, Hoffmann M, Vosberg H, Simic O, et al.. Change of sternal perfusion following preparation of the internal thoracic artery: a scintigraphical study. Eur J Cardiothorac Surg. 2000;17(1):58-62. [MedLine]
23. Rivas LF, Hawkins T, Morritt GN, Behl RP, Griffin SC, Brown AH. Radiopharmaceutical uptake as a marker of sternal blood supply following internal mammary artery harvesting. Cardiovasc Surg. 1994;2(2):203-6. [MedLine]
24. Boodhwani M, Lam BK, Nathan HJ, Mesana TG, Ruel M, Zeng W, et al. Skeletonized internal thoracic artery harvest reduces pain and dysesthesia and improves sternal perfusion after coronary artery bypass surgery: a randomized, double-blinded, within-patient comparison. Circulation. 2006;114(8):766-73. [MedLine]
25. Jesus RA, Acland RD. Anatomic study of the collateral blood supply of the sternum. Ann Thorac Surg. 1995;59(1):163-8. [MedLine]
Article receive on Thursday, October 9, 2008