Severe Aortic Stenosis: Flow-Gradient Patterns after Aortic Valve Replacement

MedicalResearch.com Interview with:
Mackram Eleid, MD
Division of Cardiovascular Diseases and Internal Medicine

MedicalResearch.com: What are the main findings of the study?

Dr. Eleid: Our study investigated the characteristics, outcomes and impact of aortic valve replacement in a large series of 1704 patients with severe aortic stenosis (aortic valve area < 1 cm2) and preserved ejection fraction (EF > 50%) according to the flow-gradient classification that incorporates both stroke volume index and mean aortic valve gradient. The primary findings were that patients with low flow, low gradient AS have lower survival than other flow-gradient patterns (a 3.2-fold increase risk of mortality compared to normal flow, low gradient), and their survival is improved with aortic valve replacement. Conversely, patients with normal flow and low gradient had a favorable survival with medical management, suggesting a less advanced stage of disease compared to the other groups. Additionally, a novel observation from this study is that patients with low flow had a higher prevalence of atrial fibrillation and previous heart failure events compared to other groups.

MedicalResearch.com: Were any of the findings unexpected?

Dr. Eleid: The high prevalence of atrial fibrillation and heart failure in patients with low flow has not been previously recognized. This group of patients also had a lower ejection fraction (although by current criteria still considered “normal”) compared to other groups. Additionally, the prevalence of low flow, low gradient pattern in this study was lower than expected, at only 3%. This may be due to exclusion of patients with concomitant valve lesions and differences in stroke volume measurement.

MedicalResearch.com: What should clinicians and patients take away from your report?

Dr. Eleid: The presence of atrial fibrillation and previous heart failure in a patient with low gradient aortic stenosis may serve as a potential marker of the syndrome of paradoxical low flow, low gradient aortic stenosis. The present study provides confirmation of results from previous studies in a large consecutive group of patients, that low flow low gradient AS is a marker of high risk and that these patients derive benefit from AVR. On the other hand, patients with normal flow, low gradient AS are a heterogeneous group that require a careful assessment to further refine assessment of AS severity and exclusion of other confounding factors such as uncontrolled hypertension and inconsistencies in severity criteria due to small body size.


MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Dr. Eleid: Future studies should further explore the interaction between atrial fibrillation and heart failure on prognosis in patients with paradoxical low flow, low gradient aortic stenosis. Additionally, more data is needed to determine optimal management strategies in patients with both normal flow and low flow low gradient aortic stenosis.

Citation:

Flow-Gradient Patterns in Severe Aortic Stenosis with Preserved Ejection Fraction: Clinical Characteristics and Predictors of Survival

Mackram F. Eleid, Paul Sorajja, Hector I. Michelena, Joseph F. Malouf, Christopher G. Scott, and Patricia A. Pellikka

Circulation. 2013;CIRCULATIONAHA.113.003695published online before print September 18 2013, doi:10.1161/CIRCULATIONAHA.113.003695