AMSTERDAM, The Netherlands—In patients with intermediate stenoses, adding fractional flow reserve (FFR) to angiography to guide CABG surgery is associated with the need for fewer grafts and a lower rate of on-pump procedures than surgery dictated by angiography alone.

The registry findings were presented September 3, 2013, at the European Society of Cardiology Congress and published online ahead of print in Circulation.

Gabor Toth, MD, and colleagues from the Cardiovascular Center Aalst (Aalst, Belgium) looked retrospectively at 627 stable or unstable patients with at least 1 intermediate stenosis (50%-70%) by coronary angiography who underwent CABG surgery at their institution. In 429 patients, surgery was based solely on angiography, while in 198 at least 1 intermediate stenosis was grafted after an FFR measurement of ≤ 0.80 or deferred with an FFR > 0.80.

FFR ‘Downgrades’ Stenosis in Some

After initial angiography, similar proportions of both angiographically guided and FFR-guided groups were assessed as having multivessel disease (94.2% and 93.9%, respectively), but after FFR assessment the proportion in the that group was downgraded to 86.4% (P = 0.002).

Fewer total anastomoses per patient were required in the FFR-guided group compared with the angiographically guided group (median of 3 [2-3] vs. 3 [2-4]; P < 0.001).

In addition, the percentage of patients with 4 or more anastomoses was higher in the angiographic group (39.6% vs. 23.2%), while the percentage with only 1 was higher in the FFR group (9.8% vs. 19.7%). Multivariable analysis showed that FFR guidance was associated with the number of anastomoses performed (Beta -0.20; 95% CI - 0.74 to - 0.33; P < 0.001).

Also, on-pump surgery was performed less frequently in the FFR-guided group compared with the angiographically guided group (49% vs. 69%; P < 0.001).

Angina Lower, Graft Patency Higher with FFR

At 36 months, there was no difference between the angiography and FFR groups in MACE (primary endpoint; all-cause death, MI, and TVR) at 12% vs. 11% (P = 0.908). While baseline rates of angina were identical between the groups (88%), at follow-up the FFR group had less Canadian Cardiovascular Society (CCS) class II-IV angina than angiographic group (31% vs. 47%; P < 0.001).

Moreover, in a subgroup of patients who underwent clinically indicated angiographic follow-up, graft patency was higher in the FFR-guided group (21% vs. 5% in the angiographic group; P = 0.031).

While acknowledging the study’s limitations, including the absence of Syntax scores and follow-up functional testing, Dr. Toth observed that FFR showed its value in term of reduced grafts. Despite this, he added, there were “no excess events after FFR-guided CABG, nor increases in CCS class at follow-up.”

Conventional Surgical Wisdom Overturned

Noting that the findings challenge conventional surgical wisdom, moderator Nawwar Al-Attar, MD, of the University of Glasgow (Glasgow, United Kingdom), said he expected the study to become a landmark. “We, as surgeons, have that ocular stenotic reflex,” he said. “We see something that is stenosed, we have the chest open, we have the grafts ready—and we just graft. We know that incomplete revascularization is associated with poor outcomes. [This study] now shows us the opposite.”

Asked by co-moderator Sigmund Silber, MD, of Cardiology Practice and Hospital (Munich, Germany), about the association of FFR with reduced angina, Dr. Toth said his hypothesis is that the occluded grafts, especially venous grafts, seen in the angiography group may embolize to the distal vessel and cause angina. “I don’t want to emphasize the difference in symptoms, but rather that there is no risk of more symptoms despite the fact that the patients have fewer grafts,” he added.

Study Details

FFR patients were younger (65 years vs. 69 years; P < 0.001). They were also more likely to be men (P = 0.010) and to have had prior PCI (P < 0.001).