DAPT improves patency of saphenous vein graft at 1 year post-CABG
DACAB - Efficacy and Safety of Dual Acetylsalicylic Acid plus Ticagrelor or Ticagrelor Alone Antiplatelet Strategy after Coronary Artery Bypass Surgery at 12 months: Randomized Multicentre Trial
Presented at ACC.17 Scientific Sessions in Anaheim, CA, USA by Qiang Zhao (Ruijin Hospital, Shanghai)
The saphenous vein graft (SVG) is still the most commonly used graft in CABG, despite its failure rate of 10-25% at 1 year and 50% at 10 years post-CABG. Dual antiplatelet therapy (DAPT) reduces MACE in patients with ACS who undergo CABG, but data regarding SVG patency is limited.
DACAB evaluated the effects of DAPT consisting of ticagrelor plus aspirin on graft patency in a small pilot study, which was terminated early because of low recruitment. The objective of this study was to compare the efficacy and safety of the combination of ticagrelor (90 mg bid) plus aspirin (100 mg qd) (T+A) with ticagrelor (90 mg bid) monotherapy (T) with aspirin (100 mg qd) monotherapy (A) on SVG patency 1 year after elective CABG. Patients between 18 and 80 years old undergoing CABG were randomized to one of these treatments in a 1:1:1 fashion, all restarted within 24 hours post CABG. The primary outcome was SVG patency by MSCTA/CAG at 1 year (ITT), and secondary outcomes included SVG patency at 7d, MACE at 1 year, recurrence of angina within 1 year, atrial fibrillation within 7 days and bleeding (TIMI criteria) within 1 year.
- SVG patency (Fitzgibbon A) was seen in 88.7% of T+A patients (P vs. A= 0.0006), 82.8% of T-treated patients (P vs. A= 0.096), and in 76.5% of A-treated patients.
- Non-occlusion (Fitzgibbon A+B) was seen in 89.9% of T+A patients (P vs. A= 0.006), 86.1% of T-treated patients (P vs. A= 0.096), and in 80.6% of A-treated patients.
- Overall, MACE was seen in 1.8% of T+A patients, in 2.4% of T-treated patients and in 5.4% of A-treated patients. CV death was observed in 0.6%, 0% and 1.2% respectively, MI in 1.2%, 1.2% and 1.8% respectively and stroke in 0%, 1.2% and 2.4%.
- CABG-related bleeding events were rare, with only 1 case in T+A- and 1 in T-treated patients.
- Non-CABG-related bleedings were more common, with 51/168 observed in the T+A group (30.4%), 20/166 (12.1%) with T alone and 15/166 (9.0%) with A alone. The majority of these bleedings were considered minimal (28.6%, 11.4% and 7.8% of patients in the respective groups).
Combination therapy with ticagrelor plus aspirin significantly improves SVG patency 1 year after CABG when compared with aspirin monotherapy, without excess risk of major bleeding.
During the press conference, discussant John Alexander (Duke Clinical Research Institute, NC, USA) wondered out loud whether the objective was relevant, which he answered with yes, as ticagrelor is used in over 20% of patients. When considering whether the trial design was appropriate, he noted that in US practice, it is a little unusual that most patients were off-CBP during CABG. With SVG patency assessed in 90-95% of patients/grafts, he thought the trial was well conducted. More information could have been given on study drug compliance and concomitant therapy. Indeed the study showed significantly more patent vein grafts with T+A vs. A, and numerically fewer MACE were see with T+A vs. T and A, although very few events were seen, and the study was underpowered. More bleeding events and numerically more major bleeding were observed with T+A. Thus, Alexander concluded that the effect of ticagrelor on SVG patency as noted in DACAB is compelling, but will be insufficient to drive changes in practice. Thus far, the effects on MACE and bleeding trade-off are not adequately addressed. Clinical trials of DAPT post-CABG with clinical outcomes are needed, to get more insight into the relationship between SVG failure and subsequent outcomes, and to assess whether ticagrelor has benefits beyond SVG patency. Several such trials are underway, in the Netherlands and in USA and Canada (effect of ticagrelor on VG patency), in Germany (effect of ticagrelor on MACE) and one in Brazil is planned (prasugrel on MACE).
- Our reporting is based on the information provided at the AHA 2017 congress -