Internal mammary hypoperfusion syndrome--diagnosis and treatment

The use of the internal mammary artery (IMA) in coronary artery bypass surgery has increased substantially over the past 20 years, being at present the conduit of choice for most patients. Complications associated with its use occur occasionally and include life-threatening postoperative ischemia or the revascularized myocardium. We reviewed the records of 1,971 consecutive patients who underwent coronary artery bypass grafting over a 5-year period. All operations included an IMA graft to the left anterior descending coronary artery. Twenty-eight of these patients (1.4%) underwent additional placement of a vein graft on the same region as a salvage maneuver for suspected hypoperfusion as a result of IMA failure. All 28 patients showed life-threatening hemodynamic compromise. Twenty-two of the 28 patients (79%) survived. This was the result of immediate surgical correction, which reversed their hemodynamic instability. IMA hypoperfusion was found more frequently in reoperations and in women and diabetic patients. This syndrome is the result of an imbalance between IMA flow and myocardial demand, causing sudden and unexpected myocardial failure. Its detection and expeditious treatment can successfully modify a serious and potentially lethal clinical situation.