Multiple studies support the use of an early invasive approach in high risk patients with non-ST elevation acute coronary syndrome (NST ACS). This benefit of an invasive strategy over the expected management has been shown in randomized studies and meta-analysis. Patients with a history of cardiac artery bypass graft (CABG) represent approximately 10% of ACS cases. This is a high risk subgroup because of their comorbidities and older age. However, these patients have often been excluded from the large studies assessing treatment strategies, such as the TIMI IIIB, REISC II and RITA 3.

Observational data show ACS + CABG patients receive fewer diagnostic studies or angioplasty procedures. This reflects higher risks associated with coronary angiograms, seeing the larger number of vessels to be assessed, the variable location of grafts and the scarce information on prior surgical procedures. The same happens when assessing revascularization, with native disease progression and the difficulty inherent to graft angioplasty, given embolization risk. 

Prior subgroup studies, with meta-analysis data, have shown patients at very high risk, of advanced age and those with chronic kidney disease, do not benefit from a routine invasive approach.  

The aim of this study was to determine whether a routine invasive approach is superior to a selective invasive or conservative approach, conducting a systematic review and meta-analysis in patients with CABG and NST ACS.

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It included 19 studies (including TACTICS-TIMI, CABG-ACS, LIPSIA-NSTEMI), with 12 eligible studies after exclusions, with a total 897 patients with NST ACS randomized to routine invasive approach (n=477) or selective/conservative (n=420). 97.4% of routine approach patients, 45.4% of the conservative, and 19.3% in the selective group received in-hospital angiographies. 

When looking at mortality, there was high heterogeneity, with average 18.7% morality for the invasive strategy and 12.9% for the conservative. There was no reduction in all-cause mortality (RR 1.12; 95% CI 0.97–1.29; P = .12), and sensitivity analysis excluding elderly patients showed the same results. 

As regards cardiac mortality, 25.2% of patients in the invasive strategy group presented this outcome vs 19.3% in the conservative management, with no significant changes in cardiac mortality risk between the strategies (RR 1.05; 95% CI 0.70–1.58; P = .81).

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When looking at acute MI, the invasive strategy patients presented 15.5% vs el 16.4%, with no significant differences (RR 0.90; 95% CI 0.65–1.23, P = .49). Some patients presented new cardiac rehospitalization, with no changes for the invasive strategy patients (19.2%) vs conservative patients (17.7%) (RR 1.05; 95% CI 0.78–1.40, P = .77).   

Conclusions

This meta-analysis of randomized studies on routine invasive strategies in patients with NST ACS and CABG (high risk subgroup) showed a routine invasive approach did not modify all-cause mortality, cardiovascular mortality, acute MI hospitalizations or cardiac hospitalizations, suggesting a lack of benefit. However, specific randomized studies are needed to confirm these findings. 

Dr. Omar Tupayachi.
Member of the Editorial Board of SOLACI.org.

Original Title: Non-ST-elevation acute coronary syndromes with previous coronary artery bypass grafting: a meta-analysis of invasive vs. conservative management.

Reference: Matthew Kelham, Rohan Vyas, Rohini Ramaseshan, Krishnaraj Rathod, Robbert J de Winter, Ruben W de Winter, Bjorn Bendz, Holger Thiele, Geir Hirlekar, Nuccia Morici, Aung Myat, Lampros K Michalis, Juan Sanchis, Vijay Kunadian, Colin Berry, Anthony Mathur, Daniel A Jones, Non-ST-elevation acute coronary syndromes with previous coronary artery bypass grafting: a meta-analysis of invasive vs. conservative management, European Heart Journal, 2024;, ehae245, https://doi.org/10.1093/eurheartj/ehae245.

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