This article is more than 5 years old. Information may no longer be current.
Operator experience plays key role in optimizing outcomes with transcatheter mitral valve repair
SAN FRANCISCO — Greater operator experience with transcatheter mitral valve repair using the MitraClip was associated with improvements in procedural success, time and complications, according to new research presented at TCT 2019.
“A potential learning curve does exist for transcatheter mitral valve repair with MitraClip. These findings have important implications as to the level of training and experience necessary to achieve optimal outcomes in this challenging patient population,” Adnan K. Chhatriwalla, MD, medical director of structural intervention at Saint Luke’s Mid America Heart Institute, said at a press conference.
Chhatriwalla and colleagues used data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (TVT) Registry to identify 14,923 MitraClip (Abbott) procedures performed from November 2013 to March 2018.
In total, 562 operators at 290 U.S. sites performed the procedures. For the purpose of this study, operators were classified by case number performed during the study period, with 116 operators performing more than 50 cases, 230 performing 26 to 50 cases and the remainder performing 25 cases or fewer.
The impact of operator experience was particularly evident when considering the goal of “optimal” mitral regurgitation (MR) reduction — or, mild or less residual MR, Chhatriwalla said.
Optimal procedural success was defined as 1+ residual MR, without death or cardiac surgery. Optimal procedural success rose with increasing operator experience, from 63.9% in the group with 1 to 25 cases to 68.4% in the group with 26 to 50 cases to 75.1% in the group with more than 50 cases (P < .001), according to a simultaneous publication in the Journal of the American College of Cardiology.
“Acceptable” procedural success, defined as 2+ residual MR, without death or cardiac surgery, also increased with experience, but to a smaller degree (91.4%, 92.4% and 93.8%, respectively; P < .001), according to the researchers.
Procedure time was reduced among operators with greater MitraClip experience, from an average of 145 minutes per procedure in the lowest-case group to 99 minutes per procedure in the highest-case group (P < .001). Radiation exposure was also significantly reduced with more experience (578 mGy, 475 mGy and 383 mGy, respectively; P < .001).
In addition, procedural complications were lowest in procedures performed by the most-experienced operators. The overall rate of composite procedural complications was 9.7% in the group that had performed 1 to 25 cases, 8.1% in the group that had performed 26 to 50 cases and 7.3% in the group that had performed more than 50 cases (P < .001). There was less frequent cardiac perforation (1%, 1.1%, 0.4%, respectively; P < .001) and blood transfusion (9.6%, 8.6%, 6.5%, respectively; P < .001) in procedures performed by the operators with the highest volume. Rates of stroke (P = .26), single leaflet device attachment (P = .11), transseptal complications (P = .25), urgent cardiac surgery (P = .42) and in-hospital mortality (P = .55) were not significantly different.
Of note, “the learning curve for MitraClip appears to flatten after approximately 50 cases. However, the overall duration of the learning curve may exceed 200 cases,” Chhatriwalla said.
In other results, the researchers observed a change in patient selection with increasing experience. For example, the operators with the greatest experience were more likely to perform urgent cases and less likely to treat patients with preexisting mitral stenosis or those who require home oxygen, according to the data.
The patients included in the study were elderly (mean age, 81 years), were predominantly white (89%) and had a high prevalence of comorbidities including diabetes, prior MI, and prior PCI and/or CABG. Most patients had grade 3+ or 4+ MR (93%) and degenerative mitral disease (86%). The median STS predicted risk of mortality (STS-PROM) was 5.7% for mitral valve repair and 8.7% for replacement, according to the results.
“As transcatheter mitral valve repair becomes more prevalent in the U.S., it may be prudent for less-experienced operators to be cognizant of where they sit on the ‘learning curve’ and to pay particular attention to case selection early in their early experience, considering that more complex patients may be referred to more experienced operators for treatment when prudent,” Chhatriwalla and colleagues wrote in JACC.
References:
Chhatriwalla AK. Late-Breaking Science 2. Presented at: TCT Scientific Symposium; Sept. 25-29, 2019; San Francisco.
Chhatriwalla AK, et al. J Am Coll Cardiol. 2019;doi:10.1016/j.jacc.2019.09.014.
Disclosure: Chhatriwalla reports he is a proctor for Edwards Lifesciences and Medtronic and is on the speakers bureau for Abbott Vascular, Edwards Lifesciences and Medtronic. Please see the study for the other authors’ relevant financial disclosures.
Perspective
Back to Top
As a general rule of thumb, the more complex the procedure, the greater the volume-outcome relationship. In other words, for a simple procedure, it is not as strong a relationship, and there is no a reason to travel across the country or across the state to be able to go to a tertiary center of care. Transcatheter mitral valve repair is a more complex procedure than transcatheter aortic valve replacement, and the volume-outcome relationship is stronger here than it is with TAVR. It is not just the operator; it’s the patient selection, it’s the type of etiology of the valve disease that is being treated and it is the intraprocedural imaging that is absolutely critical to getting this done.
This is a superb analysis. I do believe the findings; I think they are real. There are four MitraClip programs in our health care system and we are seeing issues that are related to early experience in low-volume programs.