Post-TAVR Myocardial Injury Linked to Mortality

Myocardial injury after TAVR affects 2 out of every 3 patients and increases the odds that patients will die, a multicenter registry study reports.

Much like periprocedural MI after stenting or surgery, post-TAVR myocardial injury “is not good,” Josep Rodés-Cabau, MD, of Quebec Heart and Lung Institute, Laval University (Quebec City, Canada), told TCTMD. However, it is unclear exactly what should be done to prevent it or deal with its negative consequences, he said.

For the study, published in the November 10, 2015, issue of the Journal of the American College of Cardiology, Dr. Rodés-Cabau and colleagues enrolled 1,131 consecutive TAVR patients at 13 centers in North America, South America, and Europe between March 2007 and December 2014. Both balloon-expandable (58%) and self-expanding devices (42%) were implanted, including:

• CoreValve (Medtronic) in 40.5%
• Sapien XT (Edwards Lifesciences) in 33.6%
• Sapien (Edwards Lifesciences) in 23.1%
• Sapien 3 (Edwards Lifesciences) in 1.2%
• Portico (St. Jude Medical) in 1.1%
• Inovare (Braile Biomedical, São Paulo) in 0.2%
• Lotus (Boston Scientific) in 0.1%

CK-MB levels were within normal ranges for 92.0% of patients at baseline. Two-thirds (66%) of the cohort had a rise in CK-MB (peak value of 1.6-fold; interquartile range, 0.9- to 2.8-fold) demonstrating “some degree of myocardial injury” at 12 to 24 hours post-TAVR, the paper notes. Values returned to baseline by 72 hours.

The prevalence of CK-MB levels above the upper normal values was higher in patients who had transapical compared with other access routes including transfemoral, transaortic, and trans-subclavian (97.3% vs 54.4%), as were peak median values (2.2- vs 1.2-fold; P < .001 for both).

Multivariable analysis found numerous factors predicting the overall degree of CK-MB increase between baseline and after TAVR. Among them were:

• Transapical approach
• Early TAVR experience (ie, first one-half of patients treated at each center)
• Procedural complications (eg, valve embolization/need for a second valve)
• Major/life-threatening bleeding
• Conversion to open-heart surgery

Additionally, in the patients treated with approaches other than transapical, use of a self-expanding device was linked to a slightly though significantly greater rise in CK-MB (P < .001).

The overall mortality rate was 5.7% at 30 days. Between 30 days and the end of follow-up (median, 21 months post-TAVR), an additional 29% of the original cohort had died. In all 16.9% of patients died of cardiac causes. Elevations in CK-MB independently predicted each of the mortality endpoints on multivariable analysis (table 1).

“Any increase in CK-MB levels was associated with poorer clinical outcomes, and there was a stepwise rise in late mortality according to the various degrees of CK-MB increase after TAVR,” the researchers note. They add that rises in CK-MB also had a “weak but significant impact” on LVEF changes between baseline and follow-up, while patients who had either steady or lower LVEF at 6 to 12 months compared with baseline showed greater CK-MB levels (P < .001 and = .004, respectively).

Little That is ‘Modifiable’

In an accompanying editorial, William F. Fearon, MD, and Alan C. Yeung, MD, of Stanford University Medical Center (Stanford, CA), praised the paper for providing a “real-world” perspective but emphasized that patients were not randomized to a particular TAVR approach or valve type. Moreover, it does not include the most recently available TAVR devices.

“It is not obvious why a self-expanding valve would be associated with increased myocardial injury,” they write. “Perhaps the longer procedure duration, potentially involving more manipulation of the valve within the annulus before deployment and more balloon post-dilation after deployment results in greater stress on the heart and greater opportunity for microembolization of debris down the coronary arteries.

“It is perhaps a bit discouraging that no other modifiable predictors of myocardial injury after TAVR, such as the presence of coronary disease, bore out as a factor in this study,” the editorialists add.

Asked about what can be done to limit injury, Rodés-Cabau told TCTMD that avoiding complications is the first step.

Also, “it’s clear that the transapical approach with the catheter going through the ventricular apex is clearly associated with a higher degree of myocardial injury,” he said. While it is not always possible to avoid transapical, “in particular cases, where losing myocardial muscle could be very important, [such as in] patients with very low ejection fraction or a specific cardiovascular condition, using alternative approaches (transaortic, transcarotid, subclavian) may be advisable.”

VARC-2 recommends the evaluation of biomarkers, preferably CK-MB, within 72 hours after TAVR. “But do we have specific advice regarding the different degrees of injury? The response is no,” Rodés-Cabau noted, emphasizing that “any increase” in CK-MB appears harmful. “It is difficult to say, do this or do that. But maybe closer follow-up to see the evolution of left ventricular ejection fraction, etc, is probable advisable in some of these patients. We don’t have proof yet that implementation of a treatment [like] beta-blockers or ACE inhibitors, as we use in [spontaneous MI], is useful. This has to be tested in future studies.”

Lower-profile and repositionable TAVR devices may prove helpful, he suggested. “I am convinced that with… these better devices and increasing experience of the centers, the procedures will be shorter and shorter [with] less ischemic times, less need for a second valve, less problems with embolization, etc. I think these will translate into a lower rate of myocardial injury, or at least lower degrees that are not clinically meaningful.”

Sources: 
1. Ribeiro HB, Nobela-Franco L, Muñoz-García AJ, et al. Predictors and impact of myocardial injury after transcatheter aortic valve replacement: a multicenter registry. J Am Coll Cardiol. 2015;66:2075-2088.
2. Fearon WF, Yeung AC. Clinical relevance of myocardial injury after transcatheter aortic valve replacement [editorial]. J Am Coll Cardiol. 2015;66:2089-2091.

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