Acceleration time/ejection time ratio may stratify risk in asymptomatic aortic stenosis
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Among patients with asymptomatic aortic valve stenosis, elevated acceleration time/ejection time ratio was associated with increased CV mortality and morbidity, according to data published in Circulation: Cardiovascular Imaging.
“In patients with asymptomatic, presumably mild-moderate aortic valve stenosis free from diabetes and known cardiovascular disease participating in the SEAS study, higher acceleration time/ejection time ratio was associated with increased risk of death and HF hospitalization in the total study sample and in patients with low-gradient severe aortic valve stenosis,” Eigir Einarsen, MD, PhD, of the department of clinical science at the University of Bergen, Norway, and colleagues wrote.
For this analysis, researchers evaluated the association of increased acceleration time/ejection time ratio on prognosis in 1,530 asymptomatic participants (38% women; mean age, 67 years) from the SEAS study, with presumably mild to moderate aortic valve stenosis, normal ejection fraction and no known diabetes or CVD. Researchers grouped patients according to optimal acceleration time/ejection time ratio threshold to predict CV death and HF hospitalization. Patients were identified as having low-gradient severe aortic valve stenosis if they had a combined valve area of 1 cm2 or less and mean gradient of less than 40 mm Hg.
Researchers observed that patients with an acceleration time/ejection time ratio of 0.32 or greater were younger (P = .018), had lower prevalence of hypertension (P < .001), lower systolic BP (P < .001) and more severe aortic valve stenosis by all conventional measures compared with those who had acceleration time/ejection time ratio less than 0.32.
Prognostic value
“The present post hoc analysis within the prospective SEAS study is the first to document the prognostic significance of higher acceleration time/ejection time ratio in a large cohort of asymptomatic patients with presumably mild to moderate aortic valve stenosis,” the researchers wrote. “In the total study sample, acceleration time/ejection time 0.32 was significantly associated with higher risk of cardiovascular death and HF hospitalization, independent of well-known prognosticators in aortic valve stenosis. In patients with low-gradient severe aortic valve stenosis, acceleration time/ejection time ratio > 0.32 significantly improved identification of subjects at higher risk of cardiovascular death and HF hospitalization,” the researchers wrote. “In consistently graded moderate aortic valve stenosis, acceleration time/ejection time ratio > 0.37 was found to be the optimal cutoff.”
In the low-gradient severe aortic valve stenosis subgroup, an acceleration time/ejection time ratio greater than 0.32 was associated with major CV events (HR = 1.46; 95% CI, 1.08-1.97), CV death and HF hospitalization (HR = 2.15; 95% CI, 1.22-3.77) and all-cause death (HR = 1.85; 95% CI, 1.07-3.21).
In the consistently graded moderate aortic valve stenosis subgroup, an acceleration time/ejection time ratio greater than 0.37 was associated with major CV events (HR = 2.31; 95% CI, 1.59-3.35), CV death and HF hospitalization (HR = 2.41; 95% CI, 1.04-5.59) and all-cause death (HR = 1.04; 95% CI, 0.41-2.65).
“As recommended by the guidelines, aortic valve stenosis severity, and probably acceleration time/ejection time ratio, should be reassessed when systolic blood pressure is normalized,” the researchers wrote. “However, antihypertensive treatment may often fail to normalize arterial compliance or blood pressure in elderly subjects despite appropriate treatment. An important finding is, therefore, that acceleration time/ejection time ratio > 0.32 among patients with low-gradient severe aortic valve stenosis seems to improve risk stratification independent of systolic blood pressure, low flow or hypertension. Consequently, aortic valve stenosis patients with hypertension and high acceleration time/ejection time ratio may be a particular high-risk group.”
Interpret reproducibility with caution
“Einarsen et al report good reproducibility of this parameter, as have previous reports. Such reproducibility should be interpreted with caution, as measurements were performed offline on previously acquired Doppler tracings,” Sylvestre Maréchaux, MD, PhD, of the department of cardiology at Lille Catholic University, France, and Christophe Tribouilloy, MD, PhD, of the department of cardiology at the Amiens University Hospital, France, wrote in a related editorial. “A specific test-retest reproducibility study may be more straightforward. Nevertheless, the maximal aortic flow jet velocity may be difficult to obtain using a multiview approach, even in experienced hands.
“Calculation of the acceleration time/ejection time ratio, although obtained by Doppler, has the advantage of being potentially angle independent,” the editorial authors wrote. “This parameter may be particularly helpful to confirm the aortic stenosis severity in patients with preserved EF, low-flow, low-gradient, and apparently severe aortic stenosis, and may raise the possibility that the gradients have been underestimated.”
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