Scar and Mortality in Severe Aortic Stenosis

Study Questions:

What is the prognostic significance of focal myocardial scar assessed on cardiac magnetic resonance (CMR) imaging in patients with severe aortic stenosis (AS) undergoing aortic valve replacement (AVR)?

Methods:

The authors conducted a prospective observational registry across six major centers in the United Kingdom. All subjects underwent contrast-enhanced CMR imaging using a standardized protocol. Images were centralized and analyzed using a carefully defined protocol to quantify ventricular geometry, function, and focal scar (as late gadolinium enhancement [LGE]). Patients were followed for a minimum of 2 years for a primary outcome of all-cause mortality and a secondary outcome of cardiovascular mortality.

Results:

Among 674 total subjects, focal left ventricular (LV) scar was common (present in 51% of subjects), and was more commonly noninfarct pattern (33%) than infarct pattern (18%). Men were more likely to have infarct, as were those with larger ventricles, and those with larger mass and lower ejection fraction (EF).

After a median follow-up of 3.6 years, 21.5% of patients died overall, 10.4% from cardiovascular causes. Using Cox regression, three independent predictors of mortality emerged: age (hazard ratio [HR], 1.5 per 10 years; p = 0.009), Society of Thoracic Surgeons (STS) score (HR, 1.1; p = 0.007), and scar presence (HR, 2.4; p = 0.001). For each 1% of the myocardium that was scarred, there was an 11% increased hazard of mortality. Similar results were found for cardiovascular death, with added predictors of female sex and reduced LVEF. Results were generally similar when patients who underwent surgical AVR versus transcatheter AVR (TAVR) were analyzed separately.

Conclusions:

LV scar in patients with severe AS is associated with substantially worse mortality regardless of surgical AVR or TAVR.

Perspective:

This is an important large multicenter study, which shows that LGE carries adverse prognosis in severe AS, similar to many other cardiac conditions. Critically, the degree of worsened prognosis is similar regardless of mode of AVR. Although a formal interaction analysis was not presented, these data do not support the use of LGE on CMR to select between surgical AVR and TAVR. The hypothesis that LGE on CMR can be used to select patients with severe though asymptomatic AS for TAVR is currently being evaluated in a randomized controlled trial.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Magnetic Resonance Imaging

Keywords: Aortic Valve Stenosis, Cardiac Surgical Procedures, Cicatrix, Diagnostic Imaging, Gadolinium, Heart Valve Diseases, Heart Valve Prosthesis, Magnetic Resonance Imaging, Myocardium, Stroke Volume, Transcatheter Aortic Valve Replacement


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