CAD Common in MitraClip Patients, but When and If to Fix Are Unclear – TCTMD

Among a series of 2,500 patients with mitral regurgitation (MR) treated with the MitraClip (Abbott) in the United States, nearly two-thirds had preexisting CAD, and this was associated with an increased risk of in-hospital acute myocardial infarction, a new analysis suggests.

But patients who underwent PCI for their CAD during the same index hospitalization had higher in-hospital morbidity and mortality, write Kristina Gifft, DO (University of Missouri Hospital, Columbia), and colleagues in Catheterization and Cardiovascular Interventions this week.

Findings in this subgroup of patients raise questions about the appropriate management of severe CAD and timing in MitraClip candidates, they write.

Whether to look for and treat significant coronary disease has long been debated in the setting of transcatheter aortic valve replacement. Just last week, the long-running ACTIVATION study concluded that, in the absence of significant angina, treating stenoses 70% or greater prior to TAVR increased bleeding risks without improving outcomes. ACTIVATIONs lead investigator stressed that in most cases treating the aortic stenosis itself will likely lead to symptom improvement.

Less is known about the effects of concomitant disease and any impact of treatment in the setting of MR and percutaneous repair, the authors of the current analysis point out.

Moreover, said study co-author Jad Omran, MD (Zavaro Cardiovascular Institute, El Cajon, CA), there is a lot of variation in practice, particularly in the United States, which was a key motivator for doing this study. In our practice, we typically perform angiograms to address the coronary arterial disease in all people who are undergoing MitraClip, before the procedure, he told TCTMD. But in other places people will address the mitral valve as one indication, and then will wait and see if their patient develops any clinical indications such as chest pain or acute coronary syndromes, and they will address that after the clip is in.

Mitral Regurgitation and CAD

Their retrospective analysis looked at patients included in the Nationwide Readmissions Database, drawing on ICD-10-CM/PCS codes for MitraClip, preexisting CAD, and postprocedure complications including in-hospital all-cause mortality, cardiogenic shock, acute myocardial infarction, acute kidney injury, stroke, acute respiratory failure, as well as length of hospital stay and 30-day readmission.

In all, 62.3% of patients discharged with a MitraClip also had a history of CAD. After propensity matching, a prior CAD diagnosis was associated with a higher risk of acute MI (1.6% vs 0.4%; P < 0.01). Other in-hospital endpoints, length-of-stay, and 30-day readmissions, however, were similar between groups.

Just 40 patients (1.6%) underwent PCI during the same hospitalization as their MitraClip procedure32 of whom had a prior CAD diagnosis. In PCI-treated patients, in-hospital mortality, cardiogenic shock, acute MI, acute kidney injury, stroke, and acute respiratory failure were all significantly higher, and length-of-stay was longer.

The importance [of the findings] for the community is that obviously those patients who have coronary disease do represent a higher risk group, said Steven Bailey, MD (UT Health San Antonio, TX), who commented on the paper for TCTMD. That's not earth-shattering, but I think it's confirmatory.

The presence of CAD in MR is a little more important than in aortic stenosis, he continued, because it can play a causative role. A significant number of patients with mitral regurgitation due to CAD, have both LV dilatation secondary to myocardial dysfunction [and] also either tethering of the leaflet, typically the posterior leaflet, or ischemic malapposition of the leaflets. So a primary mechanism of mitral regurgitation can be due to the myocardial ischemia itself, and it can help drive worsening during that acute hospitalization, he explained. Lack of revascularization could impact the result itself.

The current series is retrospective, subject to all of the limitations of such an approach, and notably could not distinguish between type 1 and type 2 myocardial infarction, Bailey pointed out. Still, it offers a timely reminder that the risk of concomitant PCI, the benefits of intervening, and the timing of that intervention in an era of rapidly increasing MitraClip procedures are all unknown.

To TCTMD, Omran also highlighted the limitations of the analysis, stressing the need for a randomized trial, but said for now the numbers help confirm that concomitant CAD is common in patients undergoing MitraClip. And the finding of worse outcomes among patients who underwent PCI during their MitraClip hospitalization does raise questions about the timing of the management of coronary arterial disease in patients with MitraClip, he stressed.

Given the potential for obstructive disease to be a key driver of MR, many operators would prefer to revascularize first and see whether this has an impact on MV function before proceeding with the MitraClip, Bailey pointed out.

For many of us, if we find that there is significant ischemia, particularly in the inferolateral distribution, we actually will do that, said Bailey. He stressed that concomitant or staged PCI/MitraClip procedures havent been studied prospectively, and this database wasn't set up to really look at that question. This study at least suggests that revascularization may be more important, while hammering home the point that patients with CAD are also a higher-risk group.

Its hypothesis-generating, said Bailey, but I think its a hypothesis that is worth following up on in future studies.

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CAD Common in MitraClip Patients, but When and If to Fix Are Unclear - TCTMD