Edmilson Cardoso dos Santos FilhoI; Fernando Ribeiro de Moraes NetoII; Ricardo Augusto Machado e SilvaIII; Carlos Roberto Ribeiro de MoraesIV
1. Master's Degree in Surgery at the Federal University of Pernambuco; Cardiovascular Surgeon of the Heart Institute of Pernambuco; Substitute Professor of the Surgery Department of the Health Sciences Center - Federal University of Pernambuco. 2. Full Professor at the Paulista Medical School; Cardiovascular Surgeon of the Heart Institute of Pernambuco; Adjunct Professor of the Surgery Department of the Health Sciences Center - Federal University of Pernambuco. 3. Residency in Nuclear Medicine at the Federal University of Campinas; Nuclear Physician of the Cardiac Emergency Room of Pernambuco (PROCAPE); Nuclear Physician of the Nuclear Medicine and Endocrinology Institute of Recife (CERPE) - Real Hospital Português de Beneficência of Pernambuco. 4. Titular Professor of the Thoracic Surgery Discipline at the Federal University of Pernambuco; Head Surgeon.
This study was carried out at the Heart Institute of Pernambuco (Real Hospital Português de Beneficência of Pernambuco), Recife, PE, Brazil.Correspondence To:
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.
Keywords Sternum. Mammary arteries. Tomography, emission-computed.
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.
Palavras-Chave Esterno. Artéria torácica interna. Tomografia computadorizada de emissão.
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 , increasing probability of transoperative myocardial infarction  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 . 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 .
An anatomic study suggested that the dissection of ITAs could lead to complete devascularization of the sternum , 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  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 , improper length of the graft  and infection of the sternum [15,16], as observed recently in our country .
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 . After, it was established a quantitative analysis, by comparing the uptake of radioactive tracer by the sternum with another bone structure chosen as reference . 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.
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:
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Article received on october 9, 2008.
Article accepted on march 24, 2009.