Clinical Trial: Clinical Value of Stress Echocardiography in Moderate Aortic Stenosis

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Observational

Official Title: Clinical Value of Stress Echocardiography in Moderate Aortic Stenosis

Brief Summary: The management of symptomatic patients with moderate Aortic Stenosis (AS) remains challenging and tests that would give more definitive answers are needed. The value of increase in Aortic Valve mean Gradient (AVMG), lack of change in Aortic Valve area (AVA) and calculation of valve compliance/resistance during stress echo (SE) in the symptomatic moderate AS population prognostication has to the investigators knowledge not been examined before. Similarly the additive value of myocardial blood flow reserve (MBFR), Computed Tomography (CT) calcium score, speckle tracking echocardiography, carotid ultrasonography, and N-Terminal pro B- type natriuretic peptide B (NT-proBNP) in the prognostication of this population group especially in combination with SE remains unclear.

Detailed Summary:

The prevalence of aortic valve stenosis (AS) has increased over the last few decades due to improvement in life expectancy and a growing elderly population. A wealth of data is available on patients with severe AS, whereas the risk stratification and management of patients with symptomatic moderate AS remains contentious.

Stress echocardiography (SE) is a recognised tool for the risk stratification of patients with asymptomatic severe AS. Exercise is the preferred mode of stress in this group, as it provides important prognostic information- such as presence of symptoms, overall exercise capacity and precipitation of hypotension. Significant increase in mean gradient (MG) (MG >20mmHg) is an independent predictor of valve intervention or cardiovascular death, similar to older age, diabetes and high resting gradient and this is recognised in international guidelines as a parameter to risk stratify asymptomatic severe AS. The increase in MG in the context of increasing transvalvular flow during exercise is usually accompanied by little or no change in aortic valve area (AVA). Thus, mechanistically, the increase in MG is associated with worse outcome because it reflects the intrinsic non-compliance of the aortic valve and hence resistance. A compliant valve will open to accommodate the increased flow during stress, whereas a fixed valve orifice will not, resulting in increased gradients. It is therefore advised that these patients with asymptomatic severe AS and significant increase in MG during exercise may be reasonably considered for aortic valve intervention.

In moderate AS current guidelines recommend Aortic Valve replacement (AVR) only when other cardiac surgery (coronary artery bypass grafting) is planned (class IIa). This is because patients with moderate AS are a heterogeneous group with regard to the risk of adver
Sponsor: London North West Healthcare NHS Trust

Current Primary Outcome:

  • Death (cardiovascular/all cause) [ Time Frame: between baseline and two years ]
  • Hospitalisation for heart failure [ Time Frame: between baseline and two years ]
  • Aortic valve replacement (TAVI or surgical AVR) [ Time Frame: between baseline and two years ]


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Change in AS severity (progression to severe) as measured by quantitive echocardiography [ Time Frame: Between baseline and one year ]
  • change in LV systolic function as measured by quantitive echocardiography [ Time Frame: Between baseline and one year ]


Original Secondary Outcome: Same as current

Information By: London North West Healthcare NHS Trust

Dates:
Date Received: May 19, 2016
Date Started: September 2016
Date Completion: July 2018
Last Updated: April 12, 2017
Last Verified: March 2017