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Free internal mammary artery graft in myocardial revascularization
R Verhelst1, P Y Etienne, G El Khoury
1Department of Cardiovascular and Thoracic Surgery, Université Catholique de Louvain, Belgium.
Insights
Free internal mammary artery (FIMA) grafts offer a viable alternative when pedicled grafts are unavailable. However, FIMA mid-term patency rates are lower than pedicled IMA, suggesting restricted use.
Area of Science:
- Cardiovascular Surgery
- Thoracic Surgery
- Vascular Surgery
Background:
- Coronary artery bypass grafting (CABG) is a critical intervention for ischemic heart disease.
- Internal mammary artery (IMA) grafts, particularly pedicled IMA (PIMA), are associated with superior long-term patency rates.
- Free internal mammary artery (FIMA) grafts represent an alternative when PIMA is not feasible.
Purpose of the Study:
- To evaluate the outcomes and patency rates of FIMA grafts in myocardial revascularization.
- To compare FIMA graft performance with PIMA and saphenous vein grafts.
- To determine the indications and limitations for FIMA graft utilization.
Main Methods:
- Retrospective analysis of 124 patients undergoing myocardial revascularization with at least one FIMA graft between 1986 and 1993.
- Data collection included patient demographics, preoperative conditions, surgical details, and postoperative outcomes.
- Angiographic assessment of graft patency was performed in a subset of patients.
Main Results:
- Hospital mortality was 5.6%, with cardiac-related mortality at 3.2%.
- Mid-term follow-up showed 106 out of 113 survivors (93.8%) were symptom-free.
- Global FIMA graft patency was 86.4%, with variations based on anastomosis technique and target artery. PIMA patency was 100%.
Conclusions:
- FIMA grafts can be successfully employed in myocardial revascularization, particularly when PIMA is unavailable.
- FIMA graft patency rates are favorable but inferior to PIMA grafts.
- The use of FIMA grafts should be reserved for specific situations where pedicled arterial grafts cannot be utilized.
Abstract:
Between August 1986 and March 1993, 124 patients (102 men; mean age of 59 years) underwent myocardial revascularization with the use of at least one free internal mammary artery (FIMA). This group represents 4.5% of the 2725 coronary bypasses performed during the same period. Seventy-six patients (61%) had suffered from at least one previous myocardial infarction. Forty-five patients (36%) had unstable angina; three-vessel disease was found in 100 cases (80.5%) and a left ventricular ejection fraction lower than 0.4 in 22 (17.7%). There were 18 (14.5%) redo procedures and 90 (72.5%) bilateral internal mammary artery (IMA) grafts. The reasons for using a FIMA were: too short an internal mammary artery pedicle in 83 patients, IMA injury at harvesting in 30 patients and post-bypass ischaemia in areas grafted with pedicled IMA (PIMA) in 11 patients. Cardiopulmonary bypass, moderate hypothermia (30 degrees C) and crystalloid anterograde and retrograde cardioplegia were used in all cases. Sixty-seven FIMA grafts were anastomosed directly to the ascending aorta; 57 were sutured via a saphenous hood using a running suture of polypropylene 7/0 and three were anastomosed end-to-end to a PIMA graft. FIMA grafts were directed to the left anterior descending (34%), the circumflex (37%) and the right coronary artery (29%). In total, 179 anastomoses were constructed using 127 FIMA, 136 using PIMA and 158 using saphenous veins (3.8 anastomoses per patient). Hospital mortality and postoperative myocardial infarction rates were 5.6% (seven patients) and 3.2% (four patients), respectively. Cardiac-related mortality was 3.2% (four patients); three of these four patients had been operated on for evolving infarction and one underwent a redo procedure. Four of the 117 survivors died later on; in two, it was cardiac-related and a result of global heart failure at 9 and 12 months. Of the 113 remaining patients, 106 are symptom free after a mean follow-up of 28.2 (range 3-84) months. Fifty-nine patients (50.4%) were restudied by angiography at a mean interval of 15 months. Patency rates of FIMA anastomosed either directly to the aorta or via a saphenous hood were 82.8 or 89.7%, respectively. Patency rates of FIMA directed to the left anterior descending, the circumflex and the right coronary artery were 85.7, 88 and 83.3%, respectively. Global FIMA patency was 86.4%, while global PIMA patency was 100%. The FIMA mid-term patency rates compare unfavourably with those of PIMA: FIMA should therefore be restricted to the cases where PIMA or other pedicled arterial grafts are unavailable.