‘Striking’ Rise in TAVR Among Patients With Previous CABG

Transcatheter aortic valve replacement has outstripped surgical valve replacement as the treatment of choice for patients who need intervention but have already undergone a previous CABG, but this group is not universally acknowledged in guidelines.

The growing predilection for TAVR in these patients may not surprise surgeons and interventionalists working in this space, but the magnitude of this shift is “quite striking,” Tanush Gupta, MD (Montefiore Medical Center, Bronx, NY), told TCTMD. “Once we saw that this was happening, we wanted to compare outcomes to make sure that it’s justified that TAVR is [preferentially] being used,” he added.

Gupta, who first presented these results at the TCT 2017 meeting has now published the results with co-lead investigator Sahil Khera, MD (Massachusetts General Hospital, Boston), and colleagues online in Circulation: Cardiovascular Interventions.

As previously reported by TCTMD, Gupta et al reviewed the National Inpatient Sample databases to identify adults with prior CABG who underwent isolated aortic valve replacement (AVR) between 2012 and 2014. That number was 15,055 out of 147,395, representing 10% of the entire population of patients undergoing AVR over this period.

They found that the number of prior-CABG patients treated with TAVR increased threefold, from 1,615 to 4,400, while the number undergoing SAVR went in the opposite direction, falling from 2,285 in 2012 to 1,895 in 2014. In a new analysis, published as a supplement to their paper, the authors repeated their calculations in patients without prior CABG; they found that while TAVR has increased over time in these patients, surgical replacement remains the dominant choice, used in nearly 70% of patients overall.

TAVR, SAVR Outcomes

To examine outcomes in patients with prior CABG treated via a transcatheter versus surgical approach, Gupta et al zeroed in on a propensity-matched subgroup of 3,880 paired patients within their data set. In this matched cohort, TAVR was associated with similar in-hospital mortality to SAVR (2.3% vs 2.4%), but with a lower incidence of myocardial infarction, stroke, bleeding complications, acute kidney injury. Vascular complications were similar in both groups, but—not unexpectedly—pacemaker implantations were more common in TAVR-treated patients. Length of stay was shorter in the TAVR group and, among survivors, more TAVR patients were able to leave hospital after their procedures without the need for home health services or transfer to a nursing facility.

The stroke findings are out of step with findings from randomized trials, Gupta acknowledged: 2.7% in the SAVR group versus 1.4% in the TAVR group (P < 0.001). To TCTMD, Gupta pointed out that the overall rate of cerebrovascular events in this analysis was lower than what has been seen in contemporary TAVR studies.

“These data come from administrative coding, so there could be some element of undercoding,” he speculated. “We did see lower stroke rates in the TAVR arm, but it would be premature to say that TAVR is superior in terms of stroke. Biologically, it’s hard to explain that.”

In an accompanying editorial, Homam Ibrahim, MD, and Frederick GP Welt, MD (University of Utah, Salt Lake City), summarize the “take-home messages” from the study, most notably that older patients with multiple comorbidities are typically being treated with TAVR, while relatively younger patients are being treated with surgery, “with excellent outcomes.” A key point, they add, is that the growth in TAVR in patients with prior CABG is not occurring at the expense of worse outcomes, “but in fact, with favorable outcomes.”

Doing the math, Ibrahim and Welt note that the number of patients now undergoing TAVR is far greater than the number of patients disappearing from surgery’s ranks. “This may indicate that aortic valve replacement is being offered to patients who, in the absence of TAVR—would not have otherwise received a durable treatment for their disease,” they suggest.

What the Guidelines Say

Current guidelines for the management of severe aortic stenosis are mixed when it comes to advice in patients who’ve had prior CABG. The American Heart Association/American College of Cardiology 2017 update to the 2014 valvular heart disease guidelines makes no specific mention of prior cardiac bypass surgery, but they do recommend that heart teams rely on STS scores, which include prior cardiac interventions in their calculation. Other research has suggested, however, that the STS score overestimates riskiness of AVR in patients who have had previous CABG. The 2017 European Society of Cardiology/European Association for Cardio-Thoracic Surgery guidelines, on the other hand, specify that in a patient who has had previous cardiac surgery, a transcatheter approach is “favored.”

Prior CABG is something that hasn’t always been singled out by guidelines for special consideration but is “there in the back of the minds of physicians,” Gupta said. “I think what we can get from this study is that in spite of not being a formal part of the guidelines, physicians are already using TAVR as a preferred modality, and our study shows that it’s a safe practice to do so. We can say that they have similar in-hospital mortality rates and lower in-hospital complications—all of this supports the use of TAVR over SAVR.”

Commenting on the study for TCTMD, Gilbert Tang, MD (Mount Sinai Health System, New York, NY), called it “timely,” pointing to several recent studies looking at coronary access following TAVR and the widely anticipated expansion of TAVR to lower-risk patients.

I think that the paper highlights the fact that TAVR is safe and is associated with a shorter length of stay, but the opposite message would be that surgery in this group is still relatively safe and in moderate-risk patients should not be excluded from the heart team discussion. Gilbert Tang

In Gupta et al’s analysis, propensity matching could not completely erase the fact that patients undergoing CABG were both younger and sicker, with more comorbidities and more renal disease, which could have influenced outcomes, Tang noted.

In younger patients with previous CABG, surgical valve replacement may be the better option, given the need to preserve coronary access in case of future bypass graft failure, CAD progression, or prosthetic valve failure, Tang suggested. Valve-in-TAVR procedures could, in theory, further complicate coronary access. For a prior-CABG patient at intermediate surgical risk whose grafts fail or who develop other stenoses, it’s reasonable to consider a second open-chest procedure that combines a second CABG with valve replacement, Tang told TCTMD. Finally, he continued, the long-term effects of pacemaker implantation and mild paravalvular leaks in younger patients remains unknown.

“I think that the paper highlights the fact that TAVR is safe and is associated with a shorter length of stay, but the opposite message would be that surgery in this group is still relatively safe and in moderate-risk patients should not be excluded from the heart team discussion,” Tang concluded.