MADRID — Implanting a cardiac resynchronization therapy (CRT) device at the time of coronary artery bypass grafting in patients with ischemic heart failure improves outcomes over CABG alone, a small, randomized trial showed.
The addition of CRT improved left ventricular systolic function, reduced signs of dyssynchrony, and ultimately reduced mortality through 18 months of follow-up (P<0.05 for all), according to Alexander Romanov, MD, of the Novosibirsk State Research Institute of Circulation Pathology in Russia.
Also, patients who received CRT had significantly greater improvements in NYHA functional class, six-minute walk test, and quality of life (P<0.05 for all), Romanov reported here at EUROPACE, the meeting of the European Heart Rhythm Association.
“Our data demonstrate that we don’t need to wait if patients have indications for surgery and indications for CRT,” he said. “We need to do it concomitantly.”
In a previous study of patients with ischemic heart failure, those who had left ventricular dyssynchrony before CABG tended to have dyssynchrony after surgery, showing that CABG alone was not sufficient to resynchronize the left ventricular contraction pattern in most patients, according to Romanov.
Post-CABG dyssynchrony was associated with poorer long-term outcomes.
To see whether adding epicardial CRT at the time of CABG improved outcomes, Romanov and his colleagues randomized 178 consecutive patients with severe ischemic heart failure (NYHA class III or IV) and left ventricular dyssynchrony to CABG alone or CABG plus CRT at the time of surgery.
All of the patients had indications for both CABG and CRT.
The study was conducted at three centers — one each in Russia, Poland, and Slovenia.
Dyssynchrony was defined as the presence of at least one of the following criteria: a QRS duration greater than 120 milliseconds (ms), an aortic pre-ejection delay greater than 140 ms, an interventricular mechanical delay greater than 40 ms, delayed activation of the posterolateral left ventricular wall, and tissue tracking and tissue synchronization image on tissue Doppler imaging.
The patients in the two groups were well matched at baseline, with a mean age of 62.8, a mean left ventricular ejection fraction of 29%, and a mean QRS duration of 139 ms.
Short-term postoperative outcomes were better in the group that received CRT, illustrated by a shorter average stay in the intensive care unit (2.5 versus 3.9 days) and a better cardiac index on the second day after the operation (P<0.001 for both).
Long-term outcomes through an average follow-up of 18.4 months were better in the patients who received CRT, as well.
In the CABG alone group, left ventricular ejection fraction improved slightly by three months but then returned to baseline levels. In the CABG plus CRT group, ejection fraction increased through about six months and then leveled out.
Thus, at 18 months, ejection fraction was significantly greater in the CABG plus CRT group (42% versus 28%, P=0.0001).
Measures of left ventricular dyssynchrony on tissue Doppler imaging — which was associated with all-cause death and heart failure hospitalization (HR 2.60, 95% CI 1.20 to 5.75) — improved more in the CABG plus CRT group.
Through follow-up, there were 32 deaths overall.
Four of the five that occurred in the early postoperative period were in the CABG alone group. One patient died because of ventricular fibrillation four days after the operation and three patients died because of progression of heart failure.
One patient died of postoperative MI in the CABG plus CRT group.
During the entire follow-up period, the mortality rate was significantly higher in the CABG alone group (26.4% versus 9.9%, P=0.006).
All but three of the observed deaths were cardiac — 16 pump failure deaths, 12 sudden cardiac deaths, and one death resulting from a cardiac procedure.
Three-quarters of the sudden cardiac deaths occurred in the patients who did not receive a CRT device.
Romanov reported receiving speaking honoraria from Medtronic and Biosense Webster.