HEART FAILURE COUNCIL

HEART FAILURE COUNCIL

STICHES: Coronary Bypass Surgery in Patients with Left Ventricular Dysfunction  The STICH Extension Study (STICHES) now published in the New England Journal of Medicine has reported on nearly ten years of follow-up from the original study. Over the extended follow-up period a significant survival benefit was seen in the group randomised to medical therapy plus

STICHES: Coronary Bypass Surgery in Patients with Left Ventricular Dysfunction 

The STICH Extension Study (STICHES) now published in the New England Journal of Medicine has reported on nearly ten years of follow-up from the original study. Over the extended follow-up period a significant survival benefit was seen in the group randomised to medical therapy plus CABG. Rate of death was 16% lower in those assigned to surgical treatment with an absolute difference at 10 years on Kaplan-Meier analysis of 8%.

 

Ischaemic heart disease is the most common cause of heart failure in the industrialised world. Whilst the role of coronary artery bypass grafting (CABG) in angina is established, the role of revascularisation for ischaemic cardiomyopathy is not clear. Landmark CABG trials conducted in the 1970s and ‘80s excluded patients with severe left ventricular systolic dysfunction (LVSD) and few patients had a heart failure syndrome [1-3]. Whilst these important early studies demonstrated the safety of CABG, a survival advantage in those with either normal or impaired (LVEF 40-50%) left ventricular function was not seen. Though there are clear theoretical benefits in restoring blood flow to dysfunctional myocardium, assuming that myocardial injury is not irreversible, there were no randomised data to support this hypothesis.

The ‘Surgical Treatment for Ischaemic Heart Failure’ (STICH) [4] study was conducted to determine if medical therapy plus surgical revascularisation versus medical therapy alone would offer a survival advantage in ischaemic cardiomyopathy with severe left ventricular systolic impairment (LVEF <35%). The five year results of the study did not find survival benefit with CABG (HR 0.86, 95% confidence interval 0.72-1.04,  p=0.12). The early mortality in the CABG arm probably outweighed an apparent late survival benefit. However, as an intention to treat analysis treatment arm crossover rates of 17% may have obscured potential survival benefit of CABG.

The STICH Extension Study (STICHES) [5] now published in the New England Journal of Medicine has reported on nearly ten years of follow-up from the original study. Over the extended follow-up period a significant survival benefit was seen in the group randomised to medical therapy plus CABG. Rate of death was 16% lower in those assigned to surgical treatment with an absolute difference at 10 years on Kaplan-Meier analysis of 8%. Median survival in those assigned to surgical revascularisation was 7.73 vs 6.29 years in the medical arm demonstrating that with sufficient time the surgical risk of CABG, in this study 3.6% at 30 days, is more than offset by ten years. Therefore providing compelling evidence that patients with severe LVSD and coronary disease amenable to surgical revascularisation should now be offered CABG.

However an important caveat is the characteristics of the initial study population. Whilst the mean LVEF was 26% it should be remembered that patients were young (mean age 60 years), had predominantly NYHA class II heart failure and low rates of advanced renal disease and prior cerebrovascular accident, and as such may not be representative of a general ischaemic cardiomyopathy population. Subsequently the risk of surgical treatment in a non-study population may differ from that reported in STICHES. Therefore the cardiologist, surgeon and patient should carefully consider the short and long term outcomes of CABG prior to embarking upon surgical revascularisation with regard to each patient’s risk.

Another point of interest will be the role of viability testing in patient selection for surgical treatment. The initial viability sub-study of STICH [6] did not suggest that viability is of use in determining treatment strategy. However STICHES extended follow-up data may also clarify this important issue once presented.

 

References

  1. Coronary artery surgery study (CASS): a randomized trial of coronary artery bypass surgery. Quality of life in patients randomly assigned to treatment groups. Circulation, 1983. 68(5): p. 951-60.
  2. Eleven-year survival in the Veterans Administration randomized trial of coronary bypass surgery for stable angina. The Veterans Administration Coronary Artery Bypass Surgery Cooperative Study Group. N Engl J Med, 1984. 311(21): p. 1333-9.
  3. Yusuf, S., et al., Effect of coronary artery bypass graft surgery on survival: overview of 10-year results from randomised trials by the Coronary Artery Bypass Graft Surgery Trialists Collaboration. Lancet, 1994. 344(8922): p. 563-70.
  4. Velazquez, E.J., et al., Coronary-artery bypass surgery in patients with left ventricular dysfunction. N Engl J Med, 2011. 364(17): p. 1607-16.
  5. Velazquez, E.J., et al., Coronary-Artery Bypass Surgery in Patients with Ischemic Cardiomyopathy. N Engl J Med, 2016. 374(16): p. 1511-20.
  6. Bonow, R.O., et al., Myocardial viability and survival in ischemic left ventricular dysfunction. N Engl J Med, 2011. 364(17): p. 1617-25.

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