Flow capacity of the human retrograde internal mammary artery: surgical considerations

Prevalence and Utilization of Obturator Artery Anatomic Variant in Autologous Breast Reconstruction

BACKGROUND

 The objective of this study is to quantify the prevalence and describe the utilization of an anatomic vascular variant in which the obturator artery (OA) arises from the trunk of the deep inferior epigastric artery (DIEA) in stacked/dual-pedicled autologous breast reconstruction. When this variant is identified preoperatively on computed tomography angiography (CTA), it may be utilized in a "flow-through" fashion to direct antegrade internal mammary artery (IMA) flow into a second free flap to facilitate anastomotic arrangement and optimize perfusion.

METHODS

 Preoperatively obtained abdomen/pelvis CTA imaging of 121 autologous breast reconstruction patients were retrospectively reviewed for the unilateral or bilateral presence of the OA branch arising from the DIEA (OA variant). The results were analyzed using descriptive statistics.

RESULTS

 Our analysis revealed the presence of the OA variant in 60 of the 121 (49.6%) breast reconstruction candidates, either unilaterally or bilaterally. Out of these patients, the variant was present unilaterally in 33 (55%) and bilaterally in 27 (45%) patients. Of the unilateral variants, 12 (36.4%) patients demonstrated right-sided laterality, while 21 (63.6%) patients demonstrated left-sided laterality. Clinically, this anatomic variant has been utilized in several cases of autologous breast reconstruction with flap survival in all cases.

CONCLUSION

 Utilization of this anatomic variant in stacked or dual-pedicled autologous breast reconstruction results in antegrade IMA perfusion of both primary and secondary flaps, as well as improved size match compared with other anastomotic options. Knowledge of the vascular anatomy and variations in the inferior epigastric system is crucial to both preventing complications and optimizing flap planning and outcome.

Salvage of a TRAM breast reconstruction flap using the retrograde internal mammary artery system

Background:

Free tissue transfer provides an optimal means for breast reconstruction in creating an aesthetically natural appearance that is durable over time. The choice of donor vessels vary from surgeon to surgeon, but the internal mammary axis is one of the most popular choices together with the thoracodorsal vessels.

Aims and Results:

We present the case of a salvaged free transverse rectus abdominis myocutaneous breast reconstruction in which end-to-end antegrade anastomosis to the internal mammary artery (IMA) was not possible due to frail vessel walls, but retrograde anastomosis to the IMA and antegrade anastomosis of internal mammary vessel resulted in a perfused and viable flap.

Conclusion:

We suggest the use of the retrograde internal mammary arterial system for microsurgical anastomosis when the anterograde flow is not adequate, the vessel wall is friable, and when other more common options are not available.

Mid-term patency of the inverted left internal thoracic artery conduit

In order to expand the revascularization of the left anterior descending coronary artery, we have applied the inverted left internal thoracic artery (left internal thoracic artery [LITA] transected near its origin, thus supplied by retrograde flow from superior epigastric and musculophrenic arteries) in carefully selected cases (four patients). The 64-slice multidetector row computed tomographic scans performed postoperatively (range, 6 to 40 days), as well as the scans performed in the follow-up period (range, 18 to 35 months) showed preserved inverted LITA conduits with thrombolysis in myocardial infarction (TIMI) 3 flow in all patients.

Coronary artery surgery in a patient with grossly emphysematous lung

The pedicled left internal thoracic artery graft is the mandatory conduit in coronary artery bypass surgery. A grossly emphysematous lung may sometimes present a significant problem for positioning of the pedicled left internal thoracic artery conduit. An inverted pedicled left internal thoracic artery graft (internal thoracic artery transected near its origin, thus supplied by retrograde flow from superior epigastric and musculophrenic arteries) might occasionally be the conduit of choice for those patients.

Retrograde internal mammary artery as coronary bypass. A prospective study with postoperative angiographic evaluation

Although the internal mammary artery (IMA) as a coronary graft offers better long-term patency than the saphenous vein, a factor limiting its use has been the length of the artery's pedicle. In an attempt to overcome this limitation, we evaluated the use of retrograde right IMA in a prospective study. In ten patients scheduled for routine coronary artery bypass surgery, bilateral IMA grafting was used, the left IMA in routine fashion, but the right IMA dissected from the level of the first rib, cut there and placed as an inverted graft. Three months postoperatively the patients were clinically evaluated with stress exercise test (n = 10) and coronary angiography (n = 9). No patient had recurrence of angina. Angiography revealed patency of the retrograde right IMA graft in six of nine patients. On the basis of these data we do not recommend routine use of retrograde IMA.

Physiologic characteristics of coronary artery bypass grafts

To investigate the hemodynamic characteristics of arterial grafts for coronary artery bypass grafting, we measured phasic pressure and flow patterns in three types of grafts in a canine model (n = 18). A graft from the ascending aorta (AAG), a graft from the descending aorta at the first lumbar level (DAG), analogous to a right gastroepiploic artery, and an internal thoracic artery (ITA) were anastomosed to each other. The composite graft was anastomosed to the left anterior descending coronary artery, and then the left anterior descending coronary artery was ligated. Before grafting, the AAG showed high sustained diastolic pressure, but the ITA and DAG showed rapid fall of diastolic pressures. Mean diastolic pressures were 83 +/- 2, 72 +/- 3, and 57 +/- 2 mm Hg in the AAG, ITA, and DAG (p < 0.05). Free flow in the AAG was markedly greater than in the ITA or the DAG. After grafting to the left anterior descending coronary artery, no changes were observed in diastolic pressures compared with the pregrafting values. Total blood flows were 72 +/- 6, 80 +/- 7, 57 +/- 7, and 44 +/- 6 mL/min in the left anterior descending coronary artery, AAG, ITA, and DAG, respectively. There were no differences in systolic graft flow between the three types of grafts. Diastolic blood flow in the ITA (29 +/- 4 mL/min) and DAG (18 +/- 3 mL/min) was smaller than in the AAG (48 +/- 4 mL/min) (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Right gastroepiploic artery used as a pedicled graft in a retrograde fashion

The right gastroepiploic artery is currently regarded as a most valuable arterial conduit for myocardial revascularization. We have documented a particular case wherein the proximal (pyloric) part of the right gastroepiploic artery could not be freed and was damaged because of previous cholecystectomy. The pedicle was divided at the pyloric side and raised up to be anastomosed to the posterior descending artery in a retrograde fashion. The purpose of this report is to emphasize the fact that a previous abdominal operation does not necessarily hamper the use of the gastroepiploic artery as a pedicled graft. It is also pointed out that retrograde flow in the pedicle was sufficient in this case to provide good revascularization.