Patients with a combination of left ventricular dysfunction and low aortic valve gradient, or reduced force of blood flow through the aortic valve, have higher mortality rates and a greater risk of recurrent heart failure after transcatheter aortic valve replacement (TAVR), with low aortic valve gradient the driving force behind their poor outcomes.
Patients with this profile, however, should still be considered for TAVR, especially since research on similar patients who had surgical valve replacement found that they could withstand the procedure, Suzanne J. Baron, M.D., M.Sc., the study’s lead author, said.
Low aortic valve gradient is a result of aortic stenosis, a narrowing of the opening of the aortic valve. This condition results in restricted blood flow from the left ventricle to the aorta. Stenosis can also lead to impaired left ventricular ejection fraction, meaning that the heart pumps an inadequate amount of blood with each beat.
To treat aortic stenosis, physicians typically replace the aortic valve, either through open heart surgery or through TAVR. During TAVR, a new valve is delivered to the heart through arteries in the leg or chest. For patients at high risk of surgical complications, TAVR has been shown to be at least as effective as open heart surgery.
Previous studies of valve replacement through surgery have shown that patients with impaired left ventricular ejection fraction and low aortic valve gradient do not do as well as those with better cardiac function and blood flow. In this study, researchers set out to determine the roles that left ventricular dysfunction and low aortic valve gradient play in rates of death and recurrent heart failure following this less invasive procedure.
Since left ventricular dysfunction and low aortic valve gradient are oft en seen together, researchers aimed to determine which of these factors was the driving force behind the poor clinical outcomes. Aft er adjusting for several clinical factors, including age, sex, previous cardiovascular bypass grafting, and previous angioplasty, only the presence of a low aortic valve gradient was associated with higher mortality rates and recurrent heart failure. The effect of left ventricular ejection fraction was no longer significant.
Baron, a cardiologist at Saint Luke’s Mid America Heart Institute, University of Missouri-Kansas City, in Kansas City, Missouri, said the finding that left ventricular dysfunction was not independently associated with long-term mortality after adjusting for clinical factors "provides important reassurance regarding the benefits of TAVR, even in patients with severe left ventricular dysfunction." The study results also suggest that patients with a low aortic valve gradient may be a subset of aortic stenosis patients who have less long-term benefit from this procedure, although the majority of these patients who were still alive one year after the procedure had improved quality of life. Baron concludes that "neither severe left ventricular dysfunction nor low aortic valve gradient alone or in combination provide sufficient prognostic discrimination to preclude treatment with TAVR in the absence of other adverse prognostic factors."
The American College of Cardiology http://tinyurl.com/zw28rc4