• Heart Failure
• Interventional Techniques & Devices Clinical Trials

Results from the Surgical Treatment of Ischemic Heart Failure STICH trial (NCT00023595) showed no mortality benefit from coronary artery bypass grafting (CABG) in addition to intensive guideline-based medical therapy compared with medical therapy alone. Results of the trial were presented by Eric J. Velazquez, MD, Duke University, Durham, North Carolina, USA.

The STICH trial comprised 1212 patients (median age 59 years) with coronary artery disease who were amenable to CABG and had an ejection fraction <35%. Subjects were randomly assigned to medical therapy alone (n=602) or medical therapy plus CABG (n=610). The primary study outcome was all-cause mortality. Major secondary outcomes included the rates of death from cardiovascular (CV) causes and death from any cause plus hospitalization for CV causes.

After a median follow-up of 56 months, there was no significant difference in the primary endpoint of death from any cause between those who were randomized to CABG compared with those who were randomized to medical therapy only (36% vs 41%; HR, 0.86; 95% CI, 0.72 to 1.04; p=0.12). CABG was associated with an early risk of death from any cause that persisted through 2 years. A significance level of p<0.04 was required to meet statistical significance for the primary outcome in order to compensate for interim treatment comparisons.

Secondary outcomes showed fewer deaths from CV causes in the combination group versus the medical therapy-only group (28% vs 33%; HR, 0.81; 95% CI, 0.66 to 1.00; p=0.05). Death from any cause or hospitalization for CV causes was also lower in the combination group (58% vs 68%; HR, 0.74; 95% CI, 0.64 to 0.85; p<0.001; Table 1).

Almost all (91%) of the patients who were assigned to the combination group underwent CABG, and 17% of patients in the medical therapy-only group crossed over and also underwent CABG, primarily due to progressive symptoms (40%), followed by acute decompensation (27%), patient's or family's decision (28%), and physician's decision (5%).

Two exploratory analyses were performed—one using the as-treated population (592 with medical therapy-only and 620 patients who underwent CABG during year 1 of follow-up) and the other using the per-protocol population, excluding patients who crossed over during the first year (537 medical therapy-only patients who did not cross over to CABG during the first year of follow-up and the 555 patients who were assigned to the combination group who actually underwent CABG). Results of these analyses showed a reduction in mortality in the patients who received CABG (as-treated HR, 0.70; 95% CI, 0.58 to 0.84; p<0.001; per-protocol HR, 0.76; 95% CI, 0.62 to 0.92; p=0.005). The as-treated comparison was analyzed using the Cox model, in which CABG was treated as a time-dependent covariate.

The STICH trial was originally designed with a sample size of approximately 2000 patients with an anticipated follow-up of approximately 3 years. With this design, the study would have had 90% power to detect a 25% reduction in mortality with CABG as compared with medical therapy-alone, assuming a 3-year mortality of 25% in the medical therapy-only group. Because enrollment was slower than expected, the design was modified, with a reduced sample size of 1200 and an extended follow-up of 5 years.

Overall, this important randomized trial showed no significant difference between CABG with medical therapy versus medical therapy alone. This neutral result may be in part due to inadequate power to detect differences within the range that was observed (16% reduction in hazard). While secondary and exploratory analyses suggest a benefit with CABG, these results must be interpreted with caution in this overall neutral trial.

• © 2011 MD Conference Express