CABG effects better reductions in study’s primary endpoint, but not secondary composite endpoint

In reducing the 1-year incidence of a composite of death, myocardial infarction (MI), stroke, or repeat revascularization, fractional flow reserve (FFR)-guided PCI was not non-inferior to CABG in patients with three-vessel coronary artery disease, according to a recent noninferiority study in The New England Journal of Medicine.

But researchers found that rehospitalization within 30 days, major bleeding, arrhythmias, and acute kidney injury, were more frequent in patients undergoing CABG.

“FFR is an index measured with a coronary pressure wire that provides more accurate assessment of the hemodynamic significance of a coronary stenosis than does an angiogram alone. FFR-guided PCI results in better short-term and long-term outcomes than does angiography-guided PCI or medical therapy alone. We sought to evaluate FFR-guided PCI performed with current-generation drug-eluting stents as compared with CABG with respect to the incidence of major adverse cardiac or cerebrovascular events among patients with three-vessel coronary artery disease,” wrote William F. Fearon, MD, of the Division of Cardiovascular Medicine and Stanford Cardiovascular Institute, and fellow researchers.

To do so, they randomized 1,500 patients to either FFR-guided PCI or CABG.

“All patients assigned to undergo PCI first underwent FFR assessment with a coronary pressure wire (Abbott Vascular) and intravenous or intracoronary adenosine. The protocol specified that only stenoses with an FFR of 0.80 or lower were to be treated with PCI, which was performed with durable polymer zotarolimus-eluting stents (Resolute Integrity or Resolute Onyx, Medtronic),” explained the authors.

Intravascular imaging was performed as decided by treating physicians, and all patients in both groups received aspirin and a high-dose statin, along with guideline-directed medical therapy. Those randomized to PCI received a second antiplatelet agent for at least 6 months after PCI.

The mean age of patients was 65.2 years, 81.4% were male, 93.9% were white. Most patients were hypertensive (71.2%) and dyslipidemia (68.9%). Over one-third were previous smokers (39.2%), had a previous MI (33.3%), and had been hospitalized with non–ST-segment elevation acute coronary syndrome (39.7%; NSTE-ACS). Thirteen percent had undergone previous PCI.

The primary endpoint of the study was the 1-year occurrence of a major adverse cardiac or cerebrovascular event including any-cause death, MI, stroke, or repeat revascularization. Secondary endpoints included a composite of death, MI, or stroke.

“Noninferiority of FFR-guided PCI to CABG was prespecified as an upper boundary of less than 1.65 for the 95% confidence interval of the hazard ratio,” the authors noted.

The mean number of lesions was 4.3, 22% of patients had at least one vessel with chronic total occlusion, and 68% had at least one bifurcation lesion. Those undergoing PCI received a mean of 3.7 stents, and those who underwent CABG, a mean of 3.4 distal anastomoses.

In patients randomized to FFR-guided PCI, the 1-year incidence of the composite primary end point was 10.6%, compared with 6.9% in those undergoing CABG (HR: 1.5; 95% CI: 1.1-2.2; P for noninferiority=0.35). In the incidence of the composite secondary endpoint (death, MI, or stroke), there was no significant differences between the FFR-guided PCI and CABG groups (7.3% versus 5.2%, respectively; HR: 1.4; 95% CI: 0.9-2.1). Taken separately, these endpoints were as follows:

  • Death: 1.6% versus 0.9%, respectively.
  • MI: 5.2% versus 3.5%.
  • Stroke: 0.9% versus 1.1%.

Researchers observed, however, that the incidence of the following were higher with CABG compared with FFR-guided PCI:

  • Bleeding Academic Research Consortium (BARC) type 3-5 bleeding (severe bleeding): 3.8% versus 1.6% (P˂0.01).
  • Atrial fibrillation of clinically significant arrhythmia: 14.1% versus 2.4% (P˂0.001).
  • Acute kidney injury: 0.9% versus 0.1% (P˂0.04).
  • Rehospitalization within 30 days: 10.2% versus 5.5% (P˂0.001).

“CABG resulted in a lower incidence of the composite of death, myocardial infarction, stroke, or repeat revascularization at 1 year than FFR-guided PCI in which current-generation zotarolimus-eluting stents were used. The incidence of the secondary composite end point of death, myocardial infarction, or stroke and of each individual component of the primary end point did not differ significantly between the two groups. Incidences of procedural complications such as major bleeding, acute kidney injury, arrhythmia, and rehospitalization within 30 days were higher and the mean length of hospital stay longer among the patients randomly assigned to undergo CABG,” wrote Fearon and fellow researchers.

They noted that “Among the patients assigned to undergo CABG, the better outcomes in our trial may be due to improvements in operative techniques or more effective medical therapy.”

Other limitations include the short follow-up, lack of information on quality of life and cost-efficacy, that FFR was not routinely measured in patients randomized to CABG, the use of intravascular imaging in only 12% of patients treated with PCI, failure to analyze the completeness of revascularization in both groups, and the underrepresentation of women and people of color.

  1. At 1 year, fractional flow reserve- (FFR) guided percutaneous coronary intervention (PCI) was not found to be noninferior to coronary-artery bypass graft (CABG) in lowering the incidence of a composite of death, myocardial infarction, stroke, or repeat revascularization in patients with three-vessel coronary artery disease.

  2. Rehospitalization within 30 days, major bleeding, arrhythmias, and acute kidney injury, however, were more frequent in patients undergoing CABG.

Liz Meszaros, Deputy Managing Editor, BreakingMED™

Supported by grants from Medtronic and Abbott Vascular.

Fearon has received grants from Abbott Vascular, Boston Scientific Corporation, and Medtronic USA, Inc., and has served as a consultant for CathWorks, Inc. and Siemens, and holds stock options in HeartFlow Inc.

Cat ID: 223

Topic ID: 74,223,730,223,306,308,358,5,914,192,925,492,222