Doppler Mean Gradient Is Discordant to Aortic Valve Calcium Scores in Patients with Atrial Fibrillation Undergoing Transcatheter Aortic Valve Replacement

Outcomes among patients undergoing transcatheter aortic valve replacement with very low baseline gradients

Background

While there is evidence that patients with low-flow, low-gradient aortic stenosis (AS) benefit from transcatheter aortic valve replacement (TAVR), data are lacking regarding outcomes of patients with a very low gradient (VLG).

Methods

In this retrospective, single-center study of patients with severe AS who underwent TAVR, three groups were defined using baseline mean aortic valve gradient: VLG (≤25 mmHg), low gradient (LG, 26-39 mmHg), and high gradient (HG, ≥40 mmHg). The primary outcome was the composite of Kansas City Cardiomyopathy Questionnaire (KCCQ)-12 of <45, decrease in KCCQ-12 of ≥10 compared with baseline, or death at 1 year.

Results

One-thousand six patients were included: 571 HG, 353 LG, and 82 VLG. The median age was 82.1 years [interquartile range (IQR) 76.3-86.9]; VLG patients had more baseline comorbidities compared with the other groups. The primary outcome was highest at 1 year in the VLG group (VLG, 46.7%; LG, 29.9%; HG, 23.1%; p = 0.002), with no difference between groups after adjustment for baseline characteristics. At baseline, <30% of VLG patients had an excellent or good (50-100) KCCQ-12, whereas more than 75% and 50% had an excellent or good KCCQ-12 at 30-day and 1-year follow-up, respectively.

Conclusion

Although patients with VLG undergoing TAVR have a higher rate of poor outcomes at 1 year compared with patients with LG and HG severe AS, this difference is largely attributable to baseline comorbidities. Patients with severe AS undergoing TAVR have significant improvement in health status outcomes regardless of resting mean gradient.

Impact of Atrial Fibrillation on Outcomes in Very Severe Aortic Valve Stenosis

The prevalence and impact of atrial fibrillation (AF) versus sinus rhythm (SR) on outcomes in very severe aortic stenosis (vsAS) of the native valve is unknown. The aim of the study was to determine the prognostic significance of AF in vsAS. A total of 563 patients with vsAS (transaortic valve peak velocity ≥5 m/s) and left ventricular ejection fraction ≥50% were identified retrospectively. Patients were divided by rhythm at the time of index transthoracic echocardiogram (AF: n = 50 [9%] vs SR: n = 513 [91%]). Patients with AF were older (83.1 ± 7.5 vs 72.5 ± 12.2 y, p <0.001) and had no difference in gender distribution (p = 0.49) but had a higher Charlson co-morbidity index (2 [1,3] vs 1 [0,2], p = 0.01). There was no difference in transaortic peak velocity (5.3 ± 0.3 m/s vs 5.4 ± 0.4 m/s, p = 0.13) and left ventricular ejection fraction was comparable (63 ± 7 vs 66 ± 7%, p = 0.01). Age-, gender-, Charlson co-morbidity index-, and time-dependent aortic valve replacement (AVR)-adjusted overall mortality at 5 years was significantly higher in patients with AF than patients with SR (hazard ratio [HR] 1.88 [1.23 to 2.85], p = 0.003). AVR was associated with improved survival (HR = 0.30 [0.22 to 0.42], p <0.001), with no statistically significant interaction of AVR and rhythm (p = 0.36). Outcomes were also compared in the 2 SR:1 AF propensity-matched analyses (100 SR: 50 AF), with matching done according to age, gender, clinical co-morbidities, and year of echocardiogram. In the propensity-matched analysis, age-, gender-, and time-dependent AVR-adjusted all-cause mortality was higher in AF (HR 2.32 [1.41 to 3.82], p <0.001). In conclusion, AF was not uncommon in vsAS and identified a subset of patients at a much higher risk of mortality without AVR.

Valvular Heart Disease: New Concepts in Pathophysiology and Therapeutic Approaches

This review discusses recent advancements in the field of valvular heart disease. Topics covered include recognition of the impact of atrial fibrillation on development and assessment of valvular disease, strategies for global prevention of rheumatic heart disease, understanding and management of secondary mitral regurgitation, the updated classification of bicuspid aortic valve disease, recognition of heightened cardiovascular risk associated with moderate aortic stenosis, and a growing armamentarium of transcatheter therapies.

Underestimation of Aortic Stenosis Severity by Doppler Mean Gradient during Atrial Fibrillation: Insights from Aortic Valve Weight

BACKGROUND

Doppler mean gradient (MG) can underestimate aortic stenosis (AS) severity when obtained during atrial fibrillation (AF) compared with sinus rhythm (SR). Aortic valve weight (AVW) is a flow-independent measure of AS severity. The objective of this study was to determine whether AVW or AVW/MG ratio was increased in AF versus SR in patients with AS.

METHODS

Excised native aortic valves from 495 consecutive patients (median age, 77 years; interquartile range [IQR], 71-82 years; 40% women), with left ventricular ejection fractions ≥50% who underwent surgical aortic valve replacement for native valve severe AS (aortic valve area ≤ 1 cm² or indexed aortic valve area ≤ 0.6 cm²/m²) were weighed. Excised AVW/MG ratios were compared in AF versus SR in patients with high-gradient AS (aortic peak velocity ≥ 4 m/sec or MG ≥ 40 mm Hg) and low-gradient AS (aortic peak velocity < 4 m/sec and MG < 40 mm Hg) in sex-specific analyses.

RESULTS

AF was present in 51 patients (10%; 11 of 51 [22%] had low-gradient AS) and SR in 444 (90%; 23 of 444 [5%] had low-gradient AS). There was no difference in sex distribution between AF and SR. Aortic valve area was not different, but forward stroke volume index and transaortic valve flow rate were lower in AF (P ≤ .002 for all); MG was lower in AF versus SR (median, 46 mm Hg [IQR, 37-50 mm Hg] vs 50 mm Hg [IQR, 44-61 mm Hg]; P < .0001). Overall AVW was not different (median, 2,290 mg [IQR, 1,830-3,063 mg] vs 2,140 mg [IQR, 1,530-2,958 mg]; P = .31), but overall AVW/MG ratio was higher in AF (median, 55 [IQR, 41-67] vs 42 [IQR, 30-55]; P = .001). In sex- and MG-specific analyses, the AVW/MG ratio was higher in AF compared with SR in men with high-gradient AS (median, 58 [IQR, 41-75] vs 51 [IQR, 39-61]; P = .03), but the differences were not statistically significant between AF and SR in other groups.

CONCLUSIONS

AVW was discordant to Doppler MG in AF compared with SR in men with high-gradient AS. Additional studies of the relationship of MG to other measures of AS severity, such as leaflet fibrosis, are needed.