PCI for chronic total occlusion less successful after bypass surgery

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Michael Megaly
Michael Megaly

Patients who have a percutaneous coronary intervention (PCI) for chronic total occlusion following a coronary artery bypass graft (CABG) have worse outcomes than those without prior surgery, a meta-analysis published in JACC: Cardiovascular Interventions has found. The research was due to be presented at the now-cancelled American College of Cardiology’s Scientific Session Together with World Congress of Cardiology (ACC.20/WCC), which was scheduled to take place March 28–30 in Chicago, USA.

Michael Megaly (Minneapolis Heart Institute, Abbott Northwestern Hospital, and Hennepin Healthcare, Minneapolis, USA) et al recommend: “Given the higher complexity of CTO PCIs in prior CABG patients, these procedures should ideally be performed at experienced centres by seasoned CTO operators who can promptly treat complications should they arise.”

The authors conducted a meta-analysis of studies that compared in-hospital outcomes of CTO PCI between patients with and without prior CABG, calculating odds ratios (OR) or mean difference (MD) with 95% confidence intervals (CI). They compared categorical variables using the Chi-square test, and continuous variables using the two-sample t-test. Statistical heterogeneity was considered substantial for I2 >50%, and considerable for I2 >75%. Baseline characteristics and event rates were weighted according to sample size.

Four observational studies with a total of 8,131 patients (8,544 lesions) were included: 2,163 patients (2,236 lesions) had prior CABG and 5,968 patients (6,308 lesions) did not. Patients were enrolled between 1999 and 2018. Patients with previous bypass surgery were older (67.8±8.7 vs. 64.1±9.6 years, p<0.001), and had more comorbidities and more complex lesions (J-CTO score: 2.7±1.2 vs. 2±1.3, p<0.001). Their target CTO vessel was more likely to be the right coronary artery (RCA) (54.6% vs. 50.7%) or the circumflex artery (LCX) (26.8% vs. 19.2%, p<0.001). They were more likely to undergo retrograde CTO crossing attempts (34.7% vs. 21.9%, p<0.001).

The analysis found that prior CABG was associated with lower technical success (80.7% vs. 86.5%, OR for procedural failure 1.66, 95% CI 1.42–1.94, p<0.001, I2 24%), longer fluoroscopy time (MD 16.9 minutes, 95% CI 10.3–23.7, p<0.001, I2 95%), and higher contrast use (MD 16.4ml, 95% CI 7.5–25.3, p<0.001, I2 49%). Prior CABG patients had a higher incidence of in-hospital mortality (0.8% vs. 0.3%; OR 2.77, 95% CI 1.43–5.39, p=0.003, I2 0%), coronary perforation (7.3% vs. 4.9%; OR 2.07, 95% CI 1.49–2.86, p<0.001, I2 50%), and myocardial infarction (1.4% vs. 0.5%, OR 2.46, 95% CI 1.46–4.15, p<0.001, I2 1%), but a lower incidence of cardiac tamponade (0.1% vs. 0.8%; OR 0.19, 95% CI 0.04–0.87, p=0.03, I2 11%) compared to those without prior CABG. Both groups had a similar incidence of acute cerebrovascular events (0.3% vs. 0.3%, OR 1.51, 95% CI 0.49–4.66, p=0.47, I2 15%) and vascular complications (1.7% vs. 1.2%, OR 1.39, 95% CI 0.84–2.31, p=0.2, I2 0%).

Megaly and colleagues suggest that older age, more comorbidities and more complex lesions may explain the worse outcomes in prior CABG patients, adding: “CTOs in bypassed vessels were more calcified, leading to a higher risk of procedural failure. CTO crossing in prior CABG patients often required the use of the retrograde approach which could be associated with worse outcomes.” They acknowledge that the study was limited by the small number and observational nature of the included studies, but say that the findings have implications for clinical practice.

“In patients with multivessel disease, ensuring that lesions need bypass via invasive physiological or imaging assessment is strongly recommended. Because the longevity of saphenous venous grafts is not guaranteed, CTO PCI of the native vessel might be unavoidable, and is associated with worse outcomes. A consideration of full arterial grafts, or upfront PCI to the native RCA or LCX in combination with arterial grafting of the left anterior descending artery might be favourable solutions, and should be further studied.”


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