Mortality Risk High in TAVR Patients Who Require Mechanical Circulatory Support

Extremely high-risk patients who receive a mechanical circulatory support (MCS) device during TAVR have elevated risks of dying, particularly if such support is given in an emergent or bail-out rather than a planned fashion, a new study shows.

Among patients predominantly undergoing transapical TAVR, the in-hospital mortality rate was 11% for patients with planned use of MCS and 53% with emergency use of one of the support devices, lead author Vikas Singh, MD (Massachusetts General Hospital, Boston), and colleagues report in a study published online August 22, 2016, ahead of print in the Journal of Interventional Cardiology.

The overall 1-year mortality rate was 35%, with a substantially higher risk in emergency cases (71% vs 19%).

To TCTMD, senior author Mauricio Cohen, MD (University of Miami Miller School of Medicine, FL), noted that when MCS devices are used in emergency situations it is related to a particular complication. So the worse outcomes seen in emergency versus elective cases is “not determined by the device itself,” he said, “but it’s determined by the nature of the complication for which the device was needed.”

He pointed out that MCS is used during TAVR much less frequently in the current era than when the procedure was first being introduced. The thought in the early days was that transapical TAVR, particularly in patients who had already undergone CABG, was a high-risk procedure that required such support. At the time, an intra-aortic balloon pump (IABP) was the device of choice, which explains why 87% of patients in the current study received those devices.

That is no longer routine practice. Whereas 9.4% of TAVRs were performed with MCS in this study, which included patients treated between April 2008 and December 2015, Cohen estimated that less than 5% of procedures involve MCS now. That’s because the shrinking size of TAVR technology, the availability of valves that do not require rapid pacing, and a trend toward optimizing therapies to better prepare patients for TAVR allow for a more tailored approach to using support devices, he said.

“With the availability of more technologies, I think we can individualize treatment much better now,” Cohen said.

For the study, the investigators looked at data from 577 high-risk or inoperable patients undergoing TAVR at the University of Miami; 87% had multivessel CAD and 74% underwent a transapical procedure. Median STS score was 9.4.

Receipt of an MCS device was planned in 68.5% of supported patients and emergent in the rest. Elective patients were more likely to have multivessel CAD, compromised LV systolic function, transapical procedures, and concomitant use of balloon aortic valvuloplasty. Emergency patients were older and were more likely to undergo transaortic procedures.

Though IABPs were used in the vast majority of patients who received MCS, the Impella 2.5 device (Abiomed) and extracorporeal membrane oxygenation were each used in about 6%. Median duration of support was 1 day.

Device-related complications were infrequent (4%), but mortality was high. The most common cause of in-hospital mortality was cardiogenic shock, accounting for half of deaths. Mortality remained higher for emergency versus elective patients throughout follow-up (median 18.2 months).

The authors note, however, that despite the elevated mortality risks, in-hospital and 1-year death rates were lower in the current study than in MCS-treated patients in the PARTNER trial and continued access registry (29% in the hospital and 49% at 1 year).

The disparity in mortality between elective and emergency MCS cases “may reflect the higher-risk nature of this cohort (selection bias),” Singh et al point out.

It is clear, however, that is better to use MCS in a planned rather than a bail-out fashion, Cohen said, stressing the importance of detailed discussions among the heart team about the use of MCS for individual cases. “Decisions have to be made ahead of time so the team is prepared for the worst,” he said.

Even so, there are times when unforeseen complications, such as obstruction of the coronary ostium, ventricular perforation, or unanticipated hemodynamic instability, will necessitate use of MCS, he added.

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