Dive Brief:

• A retrospective cohort study has linked pulmonary hypertension to increased mortality and readmission for heart failure in patients treated with Abbott’s MitraClip.

• Writing in JAMA Cardiology Wednesday, U.S. cardiologists showed mortality rises in line with pulmonary arterial pressure.

• The finding sparked speculation that using MitraClip to treat mitral regurgitation earlier in disease progression — before pulmonary hypertension occurs —​ may improve outcomes.

Dive Insight:

Pulmonary hypertension is an established prognostic factor in conventional mitral valve surgery, with research linking the condition to increased short and long-term mortality. However, there is a lack of data on the association between pulmonary hypertension and outcomes in patients who undergo transcatheter mitral valve repair using Abbott's MitraClip.

To assess whether a link exists, cardiologists from institutions including Massachusetts General Hospital used the Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapy registry​ to analyze outcomes in more than 4,000 patients treated with MitraClip at 232 U.S. sites between 2013 and 2017. Those patients were put in four groups based on their pulmonary arterial pressure.

The one-year mortality rate in the patients who were free from pulmonary hypertension was 16.3%. In the subgroup with severe pulmonary hypertension, the one-year mortality rate was 27.8%. The mortality rate ticked up as the extent of pulmonary hypertension went from mild to moderate to severe.

A similar trend was observed when one-year mortality was combined with readmissions for heart failure in a composite endpoint. The rate of patients experiencing one of those outcomes rose from 27.8% in patients without pulmonary hypertension to 45.2% in their counterparts with a severe form of the condition.   

While the data suggest MitraClip is associated with worse outcomes in some patients than in others, the researchers see the findings as a reason to explore using the device differently, rather than limit its use. The researchers state the data show "transcatheter mitral valve repair was safe and effective and resulted in improved functional capacity" even in patients with severe pulmonary hypertension.

To ensure more people get MitraClip when it appears to be most effective, the researchers propose intervening sooner in the progression of mitral regurgitation when patients are less likely to have developed pulmonary hypertension. More research is needed to show if that proposal will lead to improved outcomes. 

The study comes weeks after another group of researchers published a research letter in JAMA Internal Medicine examining reports of injury and device malfunction linked to MitraClip in FDA's adverse event database. The analysis identified underreporting of deaths related to MitraClip. Among the 5,323 injury and malfunction reports, researchers found 97 reports describing patient deaths not grouped with the 295 properly identified cases of death.