Continuous monitoring of left atrial (LA) pressure during MitraClip placement was telling of how well the patient did after the procedure, one center reported.
Among 50 patients with continuous direct left-sided heart pressure measurements, clip implantation generally resulted in immediate decreases in LA v-wave pressure, LA mean pressure, and left ventricular (LV) end-diastolic pressure (including when LA pressures were indexed to LV pressures to account for changes in afterload). In contrast, LV systolic pressure tended to go up.
On multivariable analysis, an unfavorable intraprocedural increase in LA mean pressure index was a predictor of heart failure rehospitalization (HR 3.377, 95% CI 3.180-3.585) and the persistence of New York Heart Association class III-IV symptoms over follow-up (HR 1.497, 95% CI 1.006-2.102), according to Francesco Maisano, MD, of University Heart Center Zurich in Switzerland, and colleagues.
Grade 2+ residual mitral regurgitation (MR) by transesophageal echocardiography, on the other hand, was not of prognostic value in these patients, they wrote online in JACC: Cardiovascular Interventions.
“This study demonstrates the value of real-time monitoring of LA pressure during MitraClip therapy to predict clinical outcomes. An increase in LA mean pressure was predictive of worse clinical outcomes at short-term follow-up, independent from echocardiographic findings,” the authors concluded.
They suggested a decrease in LA mean pressure index as the “best procedural indicator to predict improvements in functional status.”
This is a key metric during MitraClip therapy, agreed Patrice Guérin, MD, PhD, of University Hospital of Nantes, France, in an accompanying editorial.
“Indeed, in case of residual MR after implantation of a clip, operators have to decide between clip repositioning or implantation of an additional clip… The question is what is the best and what is the worst between residual MR and residual mitral stenosis in terms of clinical outcomes for a given patient?”
Based on these findings, “if the indexed LA mean pressure increases during an additional clip implantation, we may have to remove it and probably to respect the residual MR. If not, an additional clip could be implanted to limit the degree of residual MR,” Guérin said.
Most patients in the study got at least two clips, and degenerative MR was the main target of treatment. Almost all patients (94%) achieved residual MR ≤1+ at discharge, with a better MR grade observed with every additional clip implant (up to five clips).
Real-time left heart monitoring was performed with two guidewires advanced through a transseptal sheath into the left upper pulmonary vein. These guidewires were introduced before MitraClip guide catheter insertion.
Adding arterial access to the procedure resulted in one patient with an arterial hematoma requiring conservative therapy after procedure, the operators reported.
They acknowledged that the study was limited by its single-center nature and short-term follow-up.
Future studies on primary vs secondary MR are also needed, Guérin said.
He suggested that procedural LA pressure monitoring could have made the MITRA-FR trial more favorable to MitraClip therapy in secondary MR and reduced ejection fraction. Notably, the bigger COAPT trial did show better outcomes in a similar population.
Maisano and Guérin disclosed relevant relationships with Abbott.