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Transcatheter aortic valve replacement (TAVR) offers immediate and lasting benefit to patients with severe left ventricular (LV) dysfunction at an acceptable mortality risk, according to an observational study published online April 10, 2012, ahead of print in Circulation: Cardiovascular Interventions.
Chiara Fraccaro, MD, of the University of Padova (Padova, Italy), and colleagues reviewed prospectively collected data on all 384 patients with symptomatic aortic valve stenosis who underwent TAVR at 2 Italian centers between June 2007 and December 2010. All were considered inoperable or at high surgical risk. Among them, 50 (13%) had an LVEF of 35% or lower, which was accompanied by high prevalence of comorbidity and disease history.
Compared with the 334 patients (87%) with LVEF > 35%, those with severe dysfunction showed a trend toward worse device success and experienced significantly increased risk of aortic regurgitation greater than 2+/4 after TAVR. Both in-hospital and 30-day mortality were increased in this group (table 1).
Table 1. TAVR Outcomes According to LV Dysfunction
LVEF ≤ 35%(n = 50)
LVEF > 35%(n = 334)
At 1-year follow-up in 278 eligible patients, all-cause death was 29% in those with severe LV dysfunction vs. 12% in those with LVEF > 35% (P = 0.012), while cardiovascular death was similar in both groups at 10% and 6% (P = 0.434). Kaplan-Meier analysis estimated 2-year survival to be 52% in the patients with impaired LV function and 76% in the remainder (log rank P = 0.012). Predictors of late mortality were congestive heart failure, logistic EuroSCORE, and moderate-to-severe periprosthetic leakage after TAVR.
Although LVEF remained higher in the patients with superior function at baseline, only those with LVEF ≤ 35% derived significant benefit from TAVR (table 2).
Table 2. Changes in LVEF Over Follow-up
27.7 ± 6.0%
35.4 ± 11.0%a
43.6 ± 13.7%
56.5 ± 8.7%
55.9 ± 9.2%b
56.3 ± 15.0%
a P < 0.0001 vs. baseline.
b P = 0.24 vs. baseline.
Moreover, among patients with severe LV dysfunction, the greatest changes occurred in the subgroup with low-flow, high-gradient (≥ 40 mm Hg) vs. low-flow, low-gradient (< 40 mm Hg) aortic stenosis.
“The take home message for clinicians is that the presence of severe left ventricular dysfunction is not to be considered a contraindication to TAVR,” Dr. Fraccaro told TCTMD in an e-mail communication.
Worth the Risk
In a telephone interview with TCTMD, Josep Rodés-Cabau, MD, of Laval University (Quebec City, Canada), said the results confirm his own findings from an earlier study that showed patients with LV dysfunction derive early improvement after TAVR (Clavel MA. Circulation. 2010;122:1928-1936). “This [phenomenon] is quite remarkable,” he said.
Low ejection fraction has historically been a prominent reason for refusing patients surgery, Dr. Rodés-Cabau said, commenting that “honestly, it was probably a mistake, because most of these patients improve their ejection fraction. Here [in TAVR] it is also clearly demonstrated that, as a cohort of patients, they merit treatment.”
Philippe Généreux, MD, of Columbia University Medical Center (New York, NY), called the findings “striking” in an interview with TCTMD. “This is very good news that when we target a population with low LVEF, we will improve [their function],” he said, also drawing parallels to Dr. Rodés-Cabau’s results.
But while it is reasonable to treat this population with TAVR, future research including greater numbers of patients will hopefully stratify who stands to gain the most, Dr. Rodés-Cabau added. Both he and Dr. Généreux suggested that those with low flow but high gradient stenosis might fit the bill.
Dr. Généreux also said that patients treated via femoral access, which is the least injurious to the heart muscle, will have the best results. Three-quarters of patients in the current study were treated transfemorally.
How to Optimize Outcomes
Dr. Rodés-Cabau pointed out that the paper unfortunately does not detail the causes of death, but he said the observed mortality rates in the low LVEF group were unsurprising given their poor baseline characteristics. Moreover, “[t]hese patients are fragile in terms of hemodynamics. If you have any complications [during the procedure] or immediately thereafter, their tolerance is much lower as compared to patients with normal ejection fraction,” he said.
In particular, “residual regurgitation is not a good thing after TAVR,” and it may be even more important in these patients, Dr. Rodés-Cabau commented. “Meaning, you have to obtain the most perfect result possible, because the left ventricle is not going to tolerate [anything less].”
Pacemaker implantation also was unusually high at 26% in this subgroup, he suggested, which may have worsened outcomes.
Dr. Fraccaro similarly observed that periprosthetic leak would be poorly tolerated by patients with severe LV dysfunction, noting that even moderate leakage was shown to predict mortality in the PARTNER trial. “So every effort should be made to prevent it,” she said, by using multimodality imaging including multidetector CT to accurately size the device and by careful valve deployment.
Being more aggressive with postdilatation might also help prevent leakage, Dr. Généreux added.
To optimize prognosis, Dr. Généreux advised that only experienced, high-volume centers should attempt TAVR in patients with low LVEF. “You need to do the procedure [quickly, especially during transapical access and] limit the pacing runs, and to be in an environment supportive of any kind of collapse, with hemodynamic support around” as well as surgical backup, he said.
According to Dr. Fraccaro, in-hospital mortality could be minimized by proper patient selection. “First of all, it is of crucial importance to establish if the patient presents with true aortic stenosis instead of a pseudostenosis. Secondly, [evaluating] contractile reserve by dobutamine echo could help in stratifying the operative risk and the prognosis,” she said.
Use of transfemoral access when possible might also decrease mortality, Dr. Fraccaro suggested. “Finally, care should be taken to maintain a good blood pressure level during the critical procedural phase by a proper use of inotropic drugs,” she said.
Compared with those who had LVEF > 35%, those with severe LV dysfunction were significantly younger and had lower body mass index, but they also were more likely to have diabetes, prior MI, end-stage kidney disease requiring dialysis, permanent pacemaker placement, and multivessel CAD. Their procedural risk was also higher.
The choice of device, whether Sapien or Sapien XT (Edwards Lifesciences, Irvine, CA) or CoreValve (Medtronic, Minneapolis, MN), depended on availability and vessel characteristics.
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