Many Heart Failure Patients Reap QoL Gain From TAVR Despite High Mortality
Patients with severely depressed LVEF who undergo TAVR often have good hemodynamic results and reap functional benefits, but they also face substantially increased early mortality compared with those without heart failure, according to a registry study published online December 17, 2014, ahead of print in the American Journal of Cardiology. 
Though the overall findings are encouraging, a future task will be to identify the subset of patients for whom the mortality risk is so high that they may not be candidates for the procedure, said Josep Rodés-Cabau, MD, of the Quebec Heart and Lung Institute (Quebec City, Canada), in a telephone interview with TCTMD.
For the study, investigators led by Ulrich Schaefer, MD, of University Heart Center Eppendorf (Hamburg, Germany), analyzed data from 1,432 consecutive patients with severe aortic stenosis who underwent TAVR between 2009 and 2010 and were enrolled in the German Transcatheter Aortic Valve Interventions-Registry. The cohort was divided into those with LVEF ≤ 30% (n = 169) and those with an LVEF > 30% (n = 1,263).
Most patients were transfemorally implanted with the CoreValve bioprosthesis (Medtronic). Logistic EuroSCORE and the prevalence of preprocedural cardiogenic shock were almost twofold higher in those with vs without depressed LVEF (both P < .0001). In addition, low-LVEF patients were more likely to be in worse NYHA functional and American Society of Anesthesiologists operative-risk classes (both P < .0001).
Hemodynamic Success Similar
Overall procedural success was high (about 96% for both groups), and the rate of severe procedural complications was low and similar between the study arms. However, vascular complications were relatively common, occurring in about 1 in 5 of all patients.
Post-TAVR mean gradient was comparably low in both the group with low LVEF (6.0 ± 7.1 mm Hg) and the group with normal LVEF (5.9 ± 6.9 mm Hg; P = .75), although the incidence of moderate residual regurgitation was almost twice as high in patients with depressed ventricular function at baseline (23.2% vs 12.3%; P < .0001).
Moreover, patients with lower LVEF fared worse postprocedurally, with a twofold higher incidence of low cardiac output syndrome than their counterparts with a higher LVEF (P < .01). Need for resuscitation (P < .05), acute kidney failure requiring hemodialysis (P < .05), and ICD implantation (P < .0001) were also greater.
In the low-LVEF group, 30-day mortality was almost twice that of normal-LVEF patients, as were rates of death/MI and of death, MI, and stroke. The pattern of worse outcomes with low LVEF persisted at 1 year (table 1).
Post-TAVR functional status improved in both groups. At 30 days, the proportion of low-LVEF patients in NYHA class I or II rose to 80% from about 10% at baseline. Moreover, the distribution of patients in the NYHA classes became similar between the groups, with no difference in rehospitalization. Improvement in quality of life over baseline, as assessed by the EQ-5D questionnaire, was greater in patients with lower compared with higher LVEF (0.19 ± 0.3 vs 0.05 ± 0.3; P < .01). Unlike at baseline, self-assessment of health condition was now similar between the groups (P = .95), and about 84% of both were independent of any level of care.
The NYHA class distribution remained comparable for the LVEF groups at 1 year, while the gain in EQ-5D score stayed markedly higher in the low-LVEF arm compared with the higher-LVEF arm (0.22 ± 0.34 vs 0.05 ± 0.3; P < .01).
On multivariate analysis, independent predictors of 1-year mortality among low-LVEF patients were male sex, severity of baseline mitral regurgitation, and periprocedural MI or stroke.
Higher Mortality Reflects Sicker Patients
According to the authors, the data show that TAVR is both feasible and safe in patients with a depressed LVEF.
They suggest that the higher mortality in this group may be explained by the fact that the low-LVEF patients:
- Were sicker, as indicated by a higher logistic EuroSCORE and a greater likelihood of being bed-bound and having had prior aortic balloon valvuloplasty
- More frequently underwent emergent TAVR, with a much higher prevalence of cardiogenic shock and low-flow/low-gradient aortic stenosis, suggesting poor contractile reserve
Nonetheless, the investigators say, low-LVEF patients who had worse mobility, general physical capacity, and self-care ability at baseline experienced greater clinical benefit than those with normal LVEF.
Moreover, Dr. Schaefer and colleagues note, several studies have shown a larger improvement in LVEF with TAVR than surgery, which is associated with myocardial injuries that can lead to additional loss in contractile function.
When Does High Risk Become Prohibitive?
The high rate of early mortality in low-LVEF group is striking, Dr. Rodés-Cabau said, “but that’s the reality with these patients.” He added that although the researchers did not explore the connection, reduced LVEF is often accompanied by functional mitral regurgitation and pulmonary hypertension, which exacerbate the mortality risk.
He reported that other researchers are leveraging baseline and echocardiographic data from a multicenter registry to better define which low-LVEF patients are at the highest risk. “Other studies have shown that a significant proportion of these patients will increase their ejection fraction, but a significant proportion will not,” he said. “Is there a group with prohibitive risk that should not be treated? That is what we will have to focus on in the near future.”
Low flow in the presence of a low gradient—common among aortic stenosis patients with heart failure—may be an even more important mortality predictor than LVEF, Dr. Rodés-Cabau noted.
For patients with depressed LVEF who have low cardiac output syndrome following TAVR, he suggested that minimizing the number of procedural steps and rapid pacing runs may reduce not only that complication but potentially mortality.
Achieving good hemodynamic results and avoiding residual paravalvular leakage is crucial in this high-risk group, Dr. Rodés-Cabau emphasized. Hemodynamically fragile patients, especially those who are older or have no contractile reserve, have little margin of safety in handling complications, he said.
On the other hand, when these patients do respond well to TAVR and their ejection fraction increases, “they improve a lot,” Dr. Rodés-Cabau said, and this study underlines that many patients who were previously denied surgery can now be treated with TAVR.
“Hopefully in the future we will see fewer TAVR candidates with low LVEF because they will be referred earlier,” he concluded.
Source:
Schaefer U, Zahn R, Abdel-Wahab M, et al. Comparison of outcomes of patients with left ventricular ejection fractions ≤ 30% versus > 30% having transcatheter aortic valve implantation (from the German Transcatheter Aortic Valve Interventions-Registry). Am J Cardiol. 2014;Epub ahead of print.
Disclosures:
- Dr. Schaefer reports no relevant conflicts of interest.
- Dr. Rodés-Cabau reports receiving research grants from Edwards Lifesciences and St. Jude Medical.
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