Is skeletonized internal mammary harvest better than pedicle internal mammary harvest in coronary artery bypass grafting?

December 13, 2005

December 14, 2005

Behranwala A, Raja SG, Cardiothoracic Registrars (Department of Cardiothoracic Surgery, Alder Hey Hospital, Liverpool and Department of Cardiothoracic Surgery, James Cook University Hospital)

Joel Dunning, Department of Cardiothoracic Surgery, Alder Hey Hospital, Liverpool and Department of Cardiothoracic Surgery, James Cook University Hospital

In patients undergoing elective [coronary artery bypass grafting] does [skeletonised IMA] decrease [morbidity]?

You are performing coronary artery bypass grafting on a 49-year-old diabetic with triple vessel disease and normal left ventricular function. He is overweight with a body mass index of 35. You would like to give him the best possible long-term results without causing increase in morbidity. Your colleague suggests the use of bilateral skeletonised internal mammary artery, thus giving long term results due to use of internal mammary artery. You decide to use a skeletonised LIMA and two vein grafts in this high-risk case but resolve to look up the evidence after the case.

Medline 1966–Aug 2005 using the OVID interface.

[skeletoni$.mp] AND [exp Thoracic Arteries/OR exp Internal Mammary-Coronary Artery Anastomosis/OR exp Mammary Arteries/OR internal mammary.mp OR internal thoracic.mp].

One hundred and six papers were found of which 12 were selected

Skeletonisation of the internal mammary artery involves mobilization of the arterial trunk from the satellite veins and surrounding tissue, usually using a non-diathermy technique. Advocates of skeletonisation of the IMA cite preservation of sternal blood flow thereby reducing the incidence of complications, longer graft length, larger graft caliber, and greater graft flow.
Athanasiou et al. in 2004 published a systematic review and meta-analysis of studies comparing pedicled IMA harvest with skeletonised harvest. They identified a significantly increased level of free flow down skeletonised IMAs and good evidence for improved sternal vascularity, but failed to convincingly demonstrate a benefit in terms of mortality, morbidity, angiographic patency or respiratory complications for skeletonisation.

Calafiore et al. in 1999 performed 304 pedicled BIMA anastomoses and then changed to skeletonised BIMA and performed a further 842 operations. They demonstrated that the sternal wound infection rate was lower in the skeletonised group (2.5% vs. 1.7%, P<0.005) and for diabetics pedicled harvest caused a sternal infection rate of 10%. Furthermore, they showed that the angiographic patency was similar at one year, the event-free survival was similar or superior with skeletonised grafts and an extra 4 cm was gained for each graft allowing more BIMA anastomoses.

Cartier et al. reported their experience after a single surgeon changed from a pedicled to a skeletonised technique in 640 patients having off-pump CABG. There was no difference in sternal wound complications but more arterial anastomoses were possible with this technique. There was no difference in mortality and the skeletonising technique increased operative time by around 20 min.

Deja et al. assessed their experience changing from pedicled to skeletonised LIMA in 357 patients. They demonstrated that an extra 3 cm of LIMA was available, and the LIMA flow was significantly increased. There was no difference in sternal wound complications or clinical short-term outcomes.

Pevni et al. reported a sternal infection rate of only 2.2% in a consecutive cohort study of 1000 patients receiving skeletonised BIMA grafts. In particular there was no difference between diabetics and non-diabetics.

Matsa et al. compared 231 diabetic with 534 non-diabetics who received bilateral skeletonised IMAs. They found that the sternal wound infection rate was 2.6% in diabetics compared to 1.7% in non-diabetics which was a non-significant difference.

In a small retrospective study, Peterson et al. found that in 79 diabetics who received bilateral skeletonised IMAs, only one patient suffered a deep sternal wound infection (1.3%) compared to 11% of 36 diabetics who received pedicled BIMA

Lorberboym et al. performed single photon emission computed tomography (SPECT) to determine sternal vascularity post LIMA harvest. They demonstrated a significant difference between skeletonised and pedicled groups in a study of 33 patients.

Takami et al. prospectively evaluated patients receiving either a pedicled or skeletonised LIMA, using intraoperative LIMA flow after anastomosis and angiographic LIMA diameter 1 week post surgery. They found that the flow almost doubled in the LIMA graft and angiographically the LIMA diameter was slightly greater 1 week post-operatively.

Wendler et al. studied the difference in flow between 40 pedicled LIMAs and 40 skeletonied LIMAs. While no difference was initially seen after harvest, skeletonised LIMAs demonstrated 25% more flow after papaverine injection.

Sofer et al. published their findings after performing bilateral skeletonised IMAs in 545 patients. They found a sternal wound infection rate of only 1.7% with COPD and emergency operation but not diabetes increasing this risk.

Bical et al. reported their findings on 712 patients under 70 years old receiving skeletonised BIMA grafts, comparing their diabetic and non-diabetic patients. The incidence of sternal wound infection was similar, with diabetics suffering a 1.1% deep infection rate compared to a 1.2% rate in non-diabetics.

There is thus good evidence that flow and length is increased using a skeletonised technique. In addition, skeletonization is far superior to pedicled harvest for BIMA grafts in diabetics and reduces the sternal infection rate from 10% to around 2% in these patients. However, no significant differences in terms of sternal complications or vascular patency have been shown for LIMA harvest and consistently adds 15–20 min to the length of the operation.

Skeletonisation increases the length of conduit by around 3 cm and may also increase flow and conduit diameter. Skeletonisation should be the technique of choice for diabetics in whom BIMA harvest is desired, but at the expense of an extra 15–20 min per operation, no convincing outcome benefits have been shown for single IMA harvest.

1. Athanasiou T, Crossman MC, Asimakopoulos G et al.. Should the internal thoracic artery be skeletonised?
2. Calafiore AM, Vitolla G, Iaco AL et al.. Bilateral internal mammary artery grafting: midterm results of pedicled vs. skeletonised conduits.
3. Cartier R, Leacche M, Couture P.. Changing pattern in beating heart operations: use of skeletonised internal thoracic artery.
4. Deja MA, Wos S, Golba KS, Zurek P, Domaradzki W, Bachowski R, Spyt TJ.. Intraoperative and laboratory evaluation of skeletonised vs. pedicled internal thoracic artery.
5. Pevni D, Mohr R, Lev-Run O, Locer C, Paz Y, Kramer A, Shapira I.. Influence of bilateral skeletonised harvesting on occurrence of deep sternal wound infection in 1,000 consecutive patients undergoing bilateral internal thoracic artery grafting.
6. Matsa M, Paz Y, Gurevitch J, Shapira I, Kramer A, Pevny D, Mohr R.. Bilateral skeletonised internal thoracic artery grafts in patients with diabetes mellitus.
7. Peterson MD, Borger MA, Rao V, Peniston CM, Feindel CM.. Skeletonisation of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes.
8. Lorberboym M, Medalion B, Bder O, Lockman J, Cohen N, Schachner A, Cohen AJ.. 99 mTc-MDP bone SPECT for the evaluation of sternal ischaemia following internal mammary artery dissection.
9. Takami Y, Ina H.. Effects of skeletonization on intraoperative flow and anastomosis diameter of internal thoracic arteries in coronary artery bypass grafting.
10. Wendler O, Tscholl D, Huang Q, Schafers HJ.. Free flow capacity of skeletonised vs. pedicled internal thoracic artery grafts in coronary artery bypass grafts.
11. Sofer D, Gurevitch J, Shapira I, Paz Y, Matsa M, Kramer A, Mohr R.. Sternal wound infections in patients after coronary artery bypass grafting using bilateral skeletonised internal mammary arteries.
12. Bical OM, Khoury W, Fromes Y, Fischer M, Sousa UM, Boccara G, Deleuze PH.. Routine use of bilateral skeletonised internal thoracic artery grafts in middle-aged diabetic patients.