Diagnosis of an Intraoperative Aortic Dissection by Transesophageal Echocardiography During Routine Coronary Artery Bypass Grafting Surgery

Iatrogenic Aortic Dissection Associated With Cardiac Surgery: A Narrative Review

Iatrogenic aortic dissection (iAD) is a relatively rare but a life-threatening complication associated with cardiac surgery. All members of the team caring for cardiac surgical patients (surgeons, perfusionists, and anesthesiologists) must be familiar with this complication to minimize its incidence and improve outcome. The present narrative review focuses on iAD occurring intraoperatively and during the early postoperative period (within 1 month) of cardiac surgery. The review also addresses iAD that occurs late (beyond 1 month) after cardiac surgery and iAD associated with other procedures. iAD occurs in about 0.06% of cases when the ascending aorta is the site of arterial cannulation, in about 0.6% when the femoral or iliac arteries are used, and in about 0.5% when the axillary or subclavian arteries are used. Mortality is estimated to be 30% but is more than double if not recognized until the postoperative period. Site of origin of dissection is most commonly the arterial inflow cannula (∼33%). Other common sites are the aortic cross-clamp or partial occlusion clamp (∼29%) and the proximal saphenous vein anastomosis site (14%). Sixty percent of cases occur during coronary artery bypass graft (CABG) surgery and 17% during aortic valve surgery with or without CABG. iAD may be somewhat less common in off-pump versus on-pump CABG but is still not very rare. Risk factors, presentation, diagnosis, and management are reviewed in detail as is the key role of the use of echocardiography in the early diagnosis of iAD and for guiding its management.

The evolving role of the modern perfusionist: insights from transesophageal echocardiography

Transesophageal echocardiography is a relatively non-invasive, mobile, safe imaging technique that is ideal for providing real-time information on cardiac anatomy and function during heart surgery. The technology has evolved from two-dimensional to real-time three-dimensional imaging during cardiac procedures, which has significantly benefited preoperative planning, intraoperative guidance, evaluation, and postoperative follow-up. Transesophageal echocardiography may serve the clinical perfusionist by providing imaging guidance for identifying potential problems before cardiopulmonary bypass, guiding the proper placement of cannulas, monitoring cardiac performance on cardiopulmonary bypass, and providing useful feedback during weaning from cardiopulmonary bypass. Although the perfusionist should be able to understand all echocardiographic images and measurements in depth, perfusion-related echocardiographic information can or should be used to optimize the clinical practice of the modern perfusionist. Vice versa, whenever the perfusionist suspects a problem, the surgical team including the sonographer should verify this "clinical treat" by echocardiography whenever possible.

Thrombogenic Side-Effects of Recombinant Factor VIIa after use in Coronary Artery Bypass Surgery

Recombinant activated factor VII (rFVIIa) has been used ‘off licence’ to successfully treat bleeding and reduce transfusion requirements in complex cardiac surgery. However, concerns over thrombogenic side-effects have limited but not excluded its use in patients undergoing coronary artery bypass surgery (CABG).

We present two cases of CABG (one ‘on pump’ and one ‘off pump’) which were complicated by intraoperative aortic dissection and severe bleeding. In both cases the bleeding was successfully treated with rFVIIa. However the first case suffered from severe postoperative arrhythmias, myocardial infarction, cardiac arrest and worsening left ventricular dysfunction, suggesting graft patency may have been impaired, whereas the second case remained symptom-free suggesting graft patency was unaffected by the use of rFVIIa. If rFVIIa is needed to treat bleeding during CABG surgery, it may be more appropriate to administer smaller, repeated doses to minimize the risk of thrombosis and early graft failure.

Eight-year experience of intraoperative aortic dissection

Aortic dissection is a rare but devastating complication of cardiac operations. The purpose of this investigation was to assess the occurrence of aortic dissection during elective cardiac operations and the usefulness of intraoperative transesophageal echocardiography for the diagnosis and management of this complication. Data of consecutive adult patients undergoing elective cardiac surgery with transesophageal echocardiographic monitoring during an 8-year period were studied retrospectively. Aortic dissection was identified in 7 (0.13%) of 5,247 patients, and diagnosed immediately by transesophageal echocardiography in 5 of them; 2 were diagnosed later by transesophageal echocardiography. All aortic dissections were type A and they occurred after completion of the primary procedure. Two patients treated conservatively died within 5 days. Four of the 5 patients who underwent immediate reoperation survived with serious postoperative complications. Transesophageal echocardiography should be carried out when there is a risk of aortic dissection during cardiac operations, especially in the posterior wall of the ascending aorta, to avoid missing the diagnosis and delaying treatment.