Pulmonary hypertension (PH) is highly prevalent and linked to increased mortality and hospitalization among patients who underwent minimally invasive transcatheter mitral valve repair — the repair of the valve placed between the two chambers in the left side of the heart — according to a retrospective study.
The study, “Association of Pulmonary Hypertension With Clinical Outcomes of Transcatheter Mitral Valve Repair,” was published in the journal JAMA Cardiology.
The risk of death after undergoing traditional surgery for repairing the heart’s mitral valve is known to be higher in patients with PH. Defects in the mitral valve impair the pump of blood, and when the valve fails to close properly, the blood can flow back, a condition called regurgitation.
Currently, there are minimally invasive procedures for repairing the mitral valve, including the commercially available MitraClip, which uses a catheter to place a clip in the valve without requiring open-heart surgery.
However, it is still not clear if there is an association between clinical outcomes of transcatheter mitral valve repair using MitraClip and PH.
To address this, a team, led by researchers at the Massachusetts General Hospital, analyzed data from 4,071 patients who underwent mitral valve repair with the MitraClip system at more than 200 clinical sites in the U.S., part of the Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapy registry.
Specifically, they assessed how PH correlated with 30-day and one-year mortality after the procedure, and readmissions for heart failure.
The patients’ mean age was 81 years, and 1,885 (46.3%) were women and 2,186 (53.7%) men. They were categorized according to their mean pulmonary artery pressure (mPAP) into four groups: without PH (mPAP less than 25 mm Hg), with mild PH (mPAP between 25 and 34 mm Hg), moderate PH (mPAP between 35 and 44 mm Hg), and severe PH (mPAP above 45 mm Hg).
Within 30 days, the mortality and readmissions composite rate for heart failure increased progressively with the severity of PH — from 3.4% in the group without PH to 9% in the severe PH group. However, more severe PH showed no association with higher rates of hospitalization for heart failure, when comparing the more severe PH group with the control (no PH) group — 4.2% versus 2.8%.
The composite rate of one-year all-cause mortality and readmissions for heart failure was 33.6% in the overall group, but was higher among patients with more severe PH (45.2%) compared with the group without PH (27.8%).
More severe PH was associated with higher rates of readmission for heart failure at one year (27.9%), compared with the group without PH (17.7%).
Even in patients with severe PH, the valve repair was safe and resulted in improved functional capacity, as shown by improvements in the New York Heart Association functional classification, which evaluates the extent of heart failure, across the four groups.
These findings suggest that PH “was common and associated with increased mortality and readmissions for heart failure after transcatheter mitral valve repair for severe mitral regurgitation. However, even in patients with severe pulmonary hypertension, transcatheter mitral valve repair was safe and effective and resulted in improved functional capacity,” the researchers wrote.
Based on the results, the team suggested that mitral valve repair with MitraClip “should not be denied because of severe [PH].”
Nonetheless, they emphasized that further studies are needed to determine whether earlier intervention for mitral regurgitation, before PH develops, may result in improved clinical outcomes.