Figura 1. Digital angiography of the left internal mammary artery (LIMA), showing absence of distal...

Figura 2. Deployment of Terumo HydroCoils Azur. Final angiography showing the embolized high pectora...

Introduction

Several meta-analyses have documented a clear benefit of using the skeletonized left internal mammary artery (LIMA) compared with the pedicled technique, especially in a population of diabetic patients1, 2. In this group, which often presents with multivessel coronary artery disease, surgical revascularization has shown better outcomes than percutaneous intervention3. However, selecting the optimal technique between skeletonized and pedicled grafts remains a challenge. The skeletonized LIMA offers significant advantages: higher flow, better caliber, and greater length compared with the pedicled technique4. In addition, it is associated with a lower incidence of sternal wound infections. Myocardial revascularization with arterial grafts has demonstrated clinical benefits, improved survival, and lower reintervention rates in the short, medium, and long term compared with venous grafts5. In this context, the radial artery has also shown higher patency than the saphenous vein, which supports its preferential use. The success of this technique depends on the experience and skill of each surgeon.

Clinical case

We present the case of a 61-year-old patient with a history of arterial hypertension and insulin-dependent diabetes, with ischemic heart disease due to multivessel disease, who underwent myocardial revascularization surgery. An internal LIMA graft was placed to his left anterior descending artery and sequentially to the circumflex artery. Six months after the procedure, the patient reported recurrent episodes of exertional angina. An electrocardiogram recorded a ventricular arrhythmia. Doppler echocardiography showed diameters, thicknesses, and chamber function within normal parameters, and so did laboratory tests. However, during the stress test, he experienced non-sustained ventricular tachycardia (NSVT) at 5.4 METS, accompanied by chest angina, for which hospitalization was decided due to progressive unstable angina. Cardiac catheterizacion revealed two-vessel disease and a large-caliber LIMA graft, but with a large unligated high pectoral branch of the left LIMA (Figure 1), which was causing coronary steal. Endovascular resolution was chosen by means of selective embolization of the high pectoral branch.

Material and methods

In the cath lab, under aseptic and antiseptic conditions, the left radial artery was accessed by puncture with a No. 20 Abbocath device, which was then exchanged for a 6-Fr hemostatic introducer. 5000 IU of sodium heparin were administered. A 6-Fr Judkins guidewire catheter (JR 3.0) was advanced for selective cannulation of the LIMA. Through it, a Progreat (Terumo) microcatheter with a 0.014˝ hydrophilic guidewire was introduced and positioned distally. Subsequently, HydroCoils Azur (Terumo) coils were sequentially deployed until complete occlusion of the unligated pectoral branch was achieved. This type of embolic material was chosen because of its easily controlled deployment, its hydrogel coating and solid core, and because it provides effective vessel sealing, thus preventing the formation of microchannels. The final image showed flow and caliber recovery, significantly restoring coronary perfusion, particularly in the circumflex artery (Figure 2). The patient evolved without angina or arrhythmia in subsequent follow-up check-ups.

Discussion

The LIMA is widely used in myocardial revascularization surgery due to its favorable histological and physiological properties. Current evidence from retrospective studies supports that the skeletonization technique in myocardial revascularization is a safe technique, mainly in diabetic patients6. However, this technique is still subject to potential complications, among which the “steal phenomenon” represents a significant challenge7. Therefore, when skeletonization is not complete, the rate of postoperative complications increases8. Its clinical consequences manifest as recurrent angina, and its electrical consequences as the development of complex arrhythmias, as evidenced in this case9. The therapeutic approach was discussed within a multidisciplinary team, and two strategies were considered. The first consisted of surgical reintervention for direct ligation of the collateral branch, an option that was ruled out due to the patient’s high surgical risk and comorbidities. The second alternative, which was less invasive and offered encouraging results, was selective percutaneous embolization of the branch through the placement of metallic material (coils). This technique proved effective and safe, especially in this patient with high surgical risk and favorable anatomy for endovascular intervention. The embolic material was selected based on its characteristics and operator experience. The coils used allowed for controlled deployment, which facilitated complete closure of the affected vessel, preventing the formation of microchannels and achieving the objective of redirecting flow toward the coronary artery. During the planning and case analysis stage, the consideration of using diagnostic imaging tools, such as preoperative angiography and intraoperative Doppler, emerged as a relevant aspect. These techniques could provide precise information about the anatomy of the LIMA and its branches, which would be very useful for optimizing the surgical strategy. However, to date, there is insufficient bibliographic evidence to conclusively support their routine implementation in this context.

Conclusion

In this case, the cause of coronary steal was a high unligated pectoral branch, which was successfully resolved through selective embolization. After the procedure, there was a clear improvement in myocardial perfusion, and the patient remained asymptomatic during the six-month follow-up period.

1. Farkouh ME, Domanski M, Sleeper LA, et al. Strategies for multivessel revascularization in diabetic patients. N Engl J Med. 2012; 367(25):2375–2384.

2. Sá MP, Cavalcanti PE, de Andrade Costa Santos HJ, Soares, R.G. Albuquerque Miranda AF, Araújo ML, et al. Skeletonized versus pedicled bilateral internal mammary artery grafting: An analysis of outcomes and concerns through a meta-analytical approach. Int J Surg., 16 (2015), pp. 146-152

3. Di Mauro M, Iacò AL, Acitelli A, et al. Bilateral internal mammary artery for myocardial revascularization: Long-term follow-up of pedicled vs skeletonized conduits. Eur J Cardiothorac Surg. 2015; 47:698-702.

4. Benedetto U, Altman DG, Gerry S, et al. Pedicled and skeletonized internal thoracic artery grafts and sternal wound complications: Insights from the Arterial Revascularization Trial. J Thorac Cardiovasc Surg. 2016; 152:270-276.

5. Loop FD, Lytle BW, Cosgrove DM, et al. Influencia del injerto de arteria mamaria interna en la supervivencia a 10 años y eventos cardíacos. N Engl J Med. 1986; 314(1):1–6.

6. Jones EL, Craver JM, Guyton RA, et al. Importance of completeness of revascularization: long-term survival and symptomatic status in patients with triple-vessel disease. Ann Thorac Surg. 1983;36(6):574-578.

7. Jesús R, Ribeiro CN, Navas HR, et al. Arteria torácica interna esqueletizada versus pediculada: metaanálisis. Rev Bras Cir Cardiovasc. 2011; 26(3):384–390.

8. Peterson MD, Borger MA, Rao V, Feindel CM, Cohen G. Skeletonization of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes. J Thorac Cardiovasc Surg. 2003;126(5):1314-1319.

9. Pomar JL. Papel de la cirugía en la revascularización miocárdica de los pacientes con angina inestable en la era de la cardiología intervencionista. Rev Esp Cardiol. 1999; 52 (Supl 1):141-147.

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Coronary flow steal from an unligated pectoral branch during myocardial revascularization and its endovascular treatment

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