Revisiting the internal mammaries as recipient vessels in breast reconstruction: considerations in current practice

The internal mammary artery (IMA) has supplanted the thoracodorsal artery as the primary recipient vessel in autologous breast reconstruction. Additionally, the IMA continues to be the preferred bypass graft choice in patients undergoing coronary artery bypass grafting (CABG). However, practice patterns in breast reconstruction have evolved considerably since the adoption of the IMA for this application. The authors sought to evaluate the safety of IMA harvest for breast reconstruction in our current practice, given the possibility that patients may require CABG in the future.

The authors reviewed the prospective database of free flaps for breast reconstruction performed at their center from 2009 to 2017. Patients were divided into three groups (2009-2011, 2011-2013, 2014-2017) and compared on the basis of demographics, medical comorbidities, and laterality of reconstruction. Patients were further risk stratified for 10-year risk of cardiovascular events using the American College of Cardiology's atheroscletoric and cardiovascular disease (ASCVD) risk calculator.

There was a marked increase in the number of patients who underwent microsurgical breast reconstruction at our institution over the past three years (2009-2011, n = 55; 2012-2014, n = 50; 2015-2017, n = 145). The distribution of unilateral versus bilateral flaps changed meaningfully; however, they did not change statistically significantly over the study period (2009-2011 = 32.7%, 2012-2014 = 28.0%, 2015-2017 = 49.0%, p = 0.12). The rise in bilateral reconstructions over the study period is commensurate with the observed significant rise in contralateral prophylactic mastectomies (2009-2011 = 25.5%, 2012-2014 = 20.0%, 2015-2017 = 42.1%, p = 0.022). The mean 10-year risk of major cardiovascular events in the entire sample was 6.3 ± 7.1% (median 4.0%). The maximum individual risk score exceeded 25% in all three groups.

Given overall trends in breast reconstruction and the sometimes-elevated cardiac risk profiles of our patients, the authors recommend risk stratification of all patients using the proposed Breast Reconstruction Internal Mammary Assessment (BRIMA) scoring system and consideration of left internal mammary artery preservation in select cases.