Delayed chronic type A dissection following CABG: implications for evolving techniques of revascularization
1Department of Cardiothoracic Surgery, Mount Sinai Medical Center, New York, New York 10029, USA. chagl@hotmail.com
Insights
Type A aortic dissection after coronary artery bypass grafting (CABG) often originates at the partial occlusion clamp site. This complication leads to significant morbidity and mortality, highlighting the need for careful surgical technique.
Area of Science:
- Cardiovascular Surgery
- Thoracic Surgery
- Vascular Surgery
Background:
- Aortic dissection is a serious complication following cardiac surgery, with manipulation of the aorta contributing to 3-5% of deaths.
- Chronic type A dissection after prior cardiac operations presents a significant clinical challenge.
Purpose of the Study:
- To investigate the etiology and outcomes of type A aortic dissection in patients with a history of coronary artery bypass grafting (CABG).
- To identify the specific sites of intimal tears and associated risk factors in post-CABG aortic dissection.
Main Methods:
- Review of 21 patients who underwent reoperation for type A aortic dissection after isolated CABG between 1987 and 1999.
- Analysis of surgical techniques, including clamp sites, aortic diameter, and type of aortic repair (Bentall procedure vs. supracoronary anastomosis).
Main Results:
- The intimal tear was most frequently located at the partial occlusion clamp site (57.1%).
- Severe atherosclerosis and cystic media necrosis were common comorbidities (47.6% and 9.5%, respectively).
- Hospital mortality was 9.5%, with a 14.3% rate of postoperative stroke; 85.7% freedom from cardiac or aorta-related mortality at follow-up.
Conclusions:
- The partial occlusion clamp site is a common origin for type A aortic dissection after CABG.
- This complication is associated with considerable morbidity and mortality.
- The potential for increased risk of iatrogenic dissections with off-pump coronary artery bypass (OPCAB) using partial occlusion clamps warrants further investigation.
Background:
Postoperative dissection in some patients is related to manipulation of the aorta and accounts for 3% to 5% of deaths after cardiac surgery.
Methods:
Between 1987 and 1999, 109 patients with previous cardiac operations were treated for chronic type A dissection. In 31 of the patients, the etiology was related to aortic manipulation. Twenty-one patients (17 men, 4 women; 67+/-13 years of age) had isolated coronary artery bypass grafting (CABG) as their first operation and were reviewed. The interval between operations was 52.9+/-47.3 months.
Results:
Reoperation was elective in 11 patients, urgent in 10 patients. Median maximal aortic diameter was 6.8+/-2.1 cm; 9 patients had major aortic insufficiency. The intimal tear was at the partial occlusion clamp site in 12 patients (57.1%), at the cross-clamping site in 4 patients (19.1%), and at the proximal anastomosis in 1 patient (4.8%); 4 patients (19.1%) had multiple tears at several sites. Cystic media necrosis was present in 9.5% of the patients, severe atherosclerosis in 47.6% of the patients, and 42.9% of the patients had both. Nine patients (42.9%) underwent a modified Bentall procedure, 12 patients (57.1%) underwent a supracoronary anastomosis, and all had open distal anastomosis. There were two (9.5%) hospital deaths and three (14.3%) postoperative strokes. Freedom from cardiac or aorta-related mortality was 85.7% at a mean follow-up of 49.3 months.
Conclusions:
In patients who develop type A dissection of the aorta after previous CABG, the intimal tear most often is at partial occlusion clamp site. This complication is associated with morbidity and mortality. It remains to be seen whether the use of partial occlusion clamps on the pulsating and often diseased aorta during off-pump coronary artery bypass (OPCAB) will increase the risk of delayed iatrogenic dissections.
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