How can we classify aortic stenosis in patients who underwent TAVR?

Courtesy of Dr. Carlos Fava.

Aortic stenosis can present different hemodynamic patterns, such as low flow and low gradient with reduced or preserved ventricular function. However, evidence on the evolution of different hemodynamic patterns after transcatheter aortic valve replacement (TAVR) is limited.

This study consisted in a retrospective analysis of 368 patients who underwent TAVR. The population was divided in 4 groups:

1. Normal ejection fraction, and high-gradient (NEF-HG): ejection fraction (EF) ≥50%, Vmax ≥4 m/s or Pmean ≥40 mmHg and aortic valve area (AVA) ≤1 cm2 or indexed AVA ≤0.6 cm2/m2.
2. Paradoxical low-flow and low-gradient (PLF-LG): EF  ≥50%, %, Vmax ≤4 m/s or Pmean ≤40 mmHg, AVA ≤1 cm2 or indexed AVA ≤0.6 cm2/m2 and systolic volume index <35 mL/m2.
3. Low ejection fraction and high-gradient (LEF-HG): EF <50%, Vmax ≥4 m/s or Pmean ≥40 mmHg and AVA ≤1 cm2 or indexed AVA ≤0.6 cm/m2.
4. Low ejection fraction and low-gradient (LEF-LG): EF <50%, Vmax <4 m/s or Pmean <40 mmHg and AVA ≤1 cm2 or indexed AVA ≤0.6 cm/m2.

One hundred and forty-seven of those 368 patients suffered from NEF-HG (37%), 63 from LEF-HG (16%), 77 from PLF-LG (19%), and 81 from LEF-LG (20%).

Mean patient age was 82 years old (most subjects were female). NEF-HG patients were the “healthiest,” while those in the other three groups presented more comorbidities and higher surgical risk scores (particularly LEF-LG patients).

Also read: “Low Gradient Aortic Stenosis Won’t Improve with TAVR.”

No difference was observed regarding procedure or type of anesthesia used. Total procedure time, fluoroscopy time, and volume of contrast medium were similar for all groups.

In-hospital mortality within the first 30 days was lowest for NEF-HG and highest for LEF-LG patients (8.2% in NEF-HG, 17% in PLF-LG, 13% in LEF-HG and 24% in LEF-LG patients, p = 0.01). Additionally, LEF-LG patients required CPR and ventilation more frequently, and presented longer hospital stays. There was an increase in left ventricular ejection fraction in both groups with reduced ejection fraction before TAVR.

One-year mortality was 26% in the total cohort, while NEF-HG patients presented the lowest mortality rate (14.3% in that subgroup; 31.2% in PLF-LG, 22.2% in LEF-HG, and 43.2% in LEF-LG (p < 0.0001).

Also read: “TAVR in Aortic Valve Stenosis with LOTUS”.

At 5 years, the rates for all-cause mortality, cardiovascular mortality, re-hospitalization, and major adverse cardiovascular and cerebrovascular events (MACCE) were higher in the LEF-LG, LEF-HG, and PLF-LG groups.

In multivariate analysis, LEF-LG status emerged as a predictor with the highest hazard ratio for all-cause mortality, cardiovascular mortality, and MACCE. Neither baseline ejection fraction nor systolic volume index <35 mL/m2 predicted these endpoints.

Conclusion

These findings suggest that an exclusive assessment of left ventricular ejection fraction alone for outcome prediction after TAVR is inadequate. The guideline-defined subtype of aortic stenosis is what determines outcome.

Editorial Comment

This analysis shows that we must start classifying patients who have been indicated TAVR not only using ejection fraction, which is a relative number (with all its limitations), but also according to other hemodynamic factors.

While LEF-LG patients did present more comorbidities, worse renal failure, and higher risk scores, the other two groups (compared with the NEF-HG segment) presented higher all-cause and cardiovascular mortality, particularly in the case of PLF-LG patients.

In consequence, it is important for physicians to start assessing ventricular function using the systolic volume index and analyzing hemodynamic conditions. That will allow them to, on the one hand, predict ventricular function with higher accuracy and, on the other, treat patients before ejection fraction drops.

Courtesy of Dr. Carlos Fava.

Original title: Long-Term Outcomes After TAVI in Patients with Different Types of Aortic Stenosis: The Conundrum of Low Flow, Low Gradient and Low Ejection Fraction.

Reference: Miriam Puls, et al. EuroIntervention 2017;13:286-293.

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