George Chrysant gives an overview of combined revascularisation interventions for coronary and carotid disease, arguing that “carotid artery stenting and coronary artery bypass grafting as a combination appears to be significantly safer and associated with better outcomes.”
Atherosclerosis affects multiple beds in multiple people. The combination of significant coronary and carotid disease represents a small, but problematic group of patients. Significant carotid stenosis (>80%) is found in 6-12% of patients undergoing open heart surgery.1 Neurologic events occur in approximately 2% of open heart operations.1,2 Decision-making is very complicated regarding revascularisation. Symptomatic status is important. Risk of each procedure individually as well as in combination must be considered. The timing and order of revascularisation have been examined by several well-done studies. Most patients have asymptomatic carotid disease. This is important in terms of risk. Symptomatic carotid disease poses a fourfold risk of stroke. Asymptomatic disease risk is associated with degree of stenosis (Table 1).3-9
Early studies by Mackey et al and Schwartz et al showed that when compared to carotid endarterectomy (CEA) alone, the combination of CEA and coronary artery bypass grafting (CABG) carried a higher perioperative mortality and stroke rate. Mortality in the CABG group was 8% compared to 1.8% in the CEA group (p=0.035).10 Rates of stroke were 9% and 2.6% respectively for CABG compared to CEA (p=0.05).10 Of note, 57% of the patients had symptomatic carotid disease with 28% of patients having a contralateral occlusion. In a series of 582 patients undergoing CABG and CEA, the in-hospital stroke and death rate was 6.2%. All of the strokes occurred in patients with at least 80% stenosis. No strokes occurred in the patients with 50-79% stenosis.3 Therefore, both degrees of stenosis as well as symptomatic status are important considerations. In a study by Timaran et al, CEA in addition to CABG was associated with a 62% increased risk for postoperative stroke. This was a study of 27,084 patients and was weighted heavily toward the combination of CEA and CABG vs. carotid artery stenting (CAS) and CABG.11 Death and stroke as well as in-hospital death were also compared (Table 2). The SHARP study demonstrated a 7% composite event rate at 12 months in a series of 101 patients who underwent CABG immediately after CAS.12 In a study of symptomatic carotid artery disease and need for CABG where CABG was staged weeks CAS, the 30-day death and stroke rate was 3.5% with a rate of myocardial infarction of 1.5%. At five years, the percentage of patients free of all death, strokes, and MI was approximately 57%.13 The same institution demonstrated significant differences between their asymptomatic carotid patients and symptomatic patients. There was no difference in death and MI. There was a significant difference in stroke (8.8% vs. 3.1%, p=0.05). The FRIENDS study was very interesting and complex. It compared pure surgical combination revascularisation with a hybrid approach (both CAS with CABG and CEA with coronary percutaneous intervention [PCI]) and a pure endovascular approach (CAS with PCI). The results favoured a pure endovascular approach, but showed favourable outcomes for pure surgical revascularisation versus a hybrid approach where bleeding was a significant issue (Table 3).14 The purely endovascular strategy was superior to the hybrid approach for both primary and secondary outcomes (p<0.007 and p<0.001, respectively). The purely endovascular approach was superior to the purely surgical strategy for secondary outcome (p<0.006).
A comparison of staged revascularisation in 350 patients undergoing open heart surgery (92% CABG) was performed by Shishehbor et al. Carotid revascularisation was performed within a window of 90 days to open heart surgery. In 45 patients, CEA was performed followed by staged CABG. The combination of CABG and CEA was performed in 195 patients. Staged CAS after CABG was performed in 110 patients. In the first year of follow-up, CEA and staged CABG carried a composite event rate (death, stroke, MI) of 40%, driven largely by a 24% rate of myocardial infarction (p=0.001). In the longer-term follow-up period (greater than one year), the strategy of CABG with staged CAS proved to be safer than either CEA with staged open heart surgery or combination surgical revascularisation (p=0.01 and p=0.003, respectively).15 This resulted from significantly less death, rather than stroke or MI.
These studies demonstrate some of the difficulty associated with this combined disease process. Symptomatic status and degree of stenosis are important. The revascularisation strategy is also important. When evaluating the risk, studies show that the combination of CABG and CEA carries more risk than CEA alone. Data also points to worse clinical outcomes with the combination of CABG and CEA as compared to CABG and CAS. CAS and CABG as a combination appears to be significantly safer and associated with better outcomes. Therefore, it would appear that CEA and CABG should be avoided if possible in favour of CAS and CABG.
George Chrysant is chief scientific officer at INTEGRIS Hear Hosptial/INTEGRIS Cardiovascular Physicians in Oklahoma City, USA.