Mitral valve pressure gradient after percutaneous mitral valve repair: every beat counts

Long-term clinical and haemodynamic results after transcatheter annuloplasty for secondary mitral regurgitation

AIMS

The study sought to investigate the long-term outcome after transcatheter mitral valve annuloplasty for secondary mitral regurgitation (MR).

METHODS AND RESULTS

Consecutive patients with symptomatic secondary MR undergoing transcatheter mitral valve annuloplasty with the Carillon device at Leipzig University Hospital between 2012 and 2018 were studied prospectively. Left ventricular (LV) function and MR severity were quantified by standardized echocardiography. 33 patients were included. Mean age was 75 ± 10 years, and 20 patients were women. A Society of Thoracic Surgeons score of 8.1 ± 7.2% indicated high-risk status. In 24 patients, MR resulted from LV remodelling and dysfunction, eight suffered from left atrial dilatation, and one patient had MR due to combined primary and secondary aetiology. LV ejection fraction at baseline was (median) 38% [inter-quartile range (IQR) 30-49%]. During the mean follow-up time of 45 ± 20 months, 17 patients died, two patients withdraw consent, and four patients were lost. Of the remaining patients, four were hospitalized for decompensated heart failure. Two of these patients underwent additional transcatheter edge-to-edge mitral valve repair. At follow-up, New York Heart Association (NYHA) functional class improved from 95% in Class III/IV at baseline to 70% in Class I/II with no patients in NYHA Class IV (P < 0.0001). Mitral regurgitant volume was reduced from 27 mL (IQR 25-42 mL) to 8 mL (IQR 3-17 mL) (P = 0.018) and regurgitant fraction from 42% (IQR 34-54%) to 11% (IQR 8-24%) (P = 0.014). LV end-diastolic volume index [92 mL/m2 (IQR 74-107 mL/m2 ) vs. 67 mL/m2 (IQR 46-101 mL/m2 ), P = 0.065] and end-systolic volume index [50 mL/m2 (IQR 44-69 mL/m2 ) vs. 32 mL/m2 (IQR 20-53 mL/m2 ), P = 0.037] decreased. Total stroke volume remained unchanged [38 mL/m2 (IQR 33-43 mL/m2 ) vs. 33 mL/m2 (IQR 26-44 mL/m2 ), P = 0.695], while LV ejection fraction increased [43% (IQR 35-49%) vs. 54% (IQR 46-57%), P = 0.014]. Forward stroke volume, heart rate, and forward cardiac output were not significantly altered.

CONCLUSIONS

Among high-risk patients undergoing transcatheter mitral valve annuloplasty for symptomatic secondary MR, mortality was ~50% at 4 years. In the surviving patients, reduced MR severity was associated with reduced NYHA functional class, reverse LV remodelling, and improved LV function.

Gradient over Melody valve in left AV valve position reduces with beta blockade

The Melody valve, designed for implantation into the pulmonary outflow tract, can also be used to treat the pathology of atrioventricular (AV) valves. Increasing gradients are seen as an indication for re-dilating the valve. Our case demonstrates the heart rate dependency of the gradient across a Melody implanted in the left AV valve position in an infant. Beta blockers were used to lower both heart rate and gradient.

Effect of Atrial Fibrillation and Mitral Valve Gradients on Response to Percutaneous Mitral Valve Repair With the MitraClip System

Both pre-existing atrial fibrillation (AF) and mitral valve pressure gradients (MVPG) created by MitraClip implantation have demonstrated predictive power for unfavorable outcomes. Therefore, we aimed to assess the impact of MVPG following MitraClip on outcomes in patients with and without AF. A total of 200 patients who underwent MitraClip implantation in our institution were enrolled. Echocardiography was obtained before and after the procedure. The primary endpoint of the study was all-cause mortality 1-year after MitraClip implantation. Secondary end points were clinical improvements in NYHA functional class and reduction in MR severity after MitraClip implantation. Two hundred patients (74 ± 10 years, left ventricular ejection fraction 41% ± 14%, logistic EuroSCORE I 21 ± 15) were enrolled into the final analysis. One hundred twelve patients (56%) had pre-existing AF. One-year all-cause mortality was 17% without any differences between patients with or without pre-existing AF. Comparing postprocedural MVPG of surviving and deceased patients, deceased patients with pre-existing AF exhibited significantly elevated postprocedural MVPG compared with surviving patients without AF (4.8 ± 2.1 mm Hg vs 3.6 ± 1.8 mm Hg; p = 0.010). ROC analysis and Kaplan-Meier survival curves identified significantly reduced survival in AF patients with postprocedural MVPG above 4.0 mm Hg (p = 0.011). After MitraClip, a MVPG above 4.0 mm Hg in patients with pre-existing AF was a significant outcome predictor in univariate and multivariate analysis. In conclusion, we identified a high-risk cohort characterized by postprocedural MVPG above 4.0 mm Hg and pre-existing AF predicting poor long-term outcome.

Impact of simulated MitraClip on forward flow obstruction in the setting of mitral leaflet tethering: An in vitro investigation

OBJECTIVES

We aimed to evaluate diastolic leaflet tethering as a factor that may cause mitral stenosis (MS) after simulated MitraClip implantation, using an in vitro left heart simulator.

BACKGROUND

Leaflet tethering commonly seen in functional mitral regurgitation may be a significant factor affecting the severity of MS after MitraClip implantation.

METHODS

A left heart simulator with excised ovine mitral valves (N = 6), and custom edge-to-edge clip devices (GTclip) was used to mimic implantation of MitraClip in a variety of positions. Anterior mitral leaflet (AML) tethering severity was varied for each case (leaflet excursion of 75°, 60°, and 45°, consistent with mild, moderate and severe tethering), and the baseline mitral annular area (MAA) was varied across samples (3.6-4.8 cm² ). The resulting mitral valve area (MVA), and peak/mean mitral valve gradient (MVG) were measured in each case.

RESULTS

AML tethering severity was a highly significant factor increasing MVG and decreasing MVA (P < 0.001). When GTclip placement was simulated with severe AML tethering, mean MVG >5 mmHg resulted more frequently than with GTclip placement alone (46% vs. 4%, respectively). However, severe AML tethering alone significantly reduced baseline MVA to 3.6 ± 0.2 cm² , and increased baseline MVG to 3.0 ± 0.4 mmHg. At MAA above 4.7 cm² , severe AML tethering did not cause moderate MS, even with placement of two GTclips (95% confidence).

CONCLUSIONS

Our results show that diastolic AML tethering may predispose to MS after clip placement, however, MS was not observed when baseline MVA was above 4.0 cm² . Severity of AML tethering may be an important criterion in selecting patients for edge-to-edge repair.

Mitral valve interventions in heart failure

Secondary mitral regurgitation (MR) results from left ventricular dilatation and dysfunction. Quantification of secondary MR is challenging because of the underlying myocardial disease. Clinical and echocardiographic evaluation requires a multi‐parametric approach. Severe secondary MR occurs in up to one‐fourth of patients with heart failure with reduced ejection fraction, which is associated with a mortality rate of 40% to 50% in 3 years. Percutaneous edge‐to‐edge mitral valve repair (MitraClip) has emerged as an alternative to surgical valve repair to improve symptoms, functional capacity, heart failure hospitalizations, and cardiac haemodynamics. Further new transcatheter strategies addressing MR are evolving. The Carillion, Cardioband, and Mitralign devices were designed to reduce the annulus dilatation, which is a frequent and important determinant of secondary MR. Several transcatheter mitral valve replacement systems (Tendyne, CardiAQ‐Edwards, Neovasc, Tiara, Intrepid, Caisson, HighLife, MValve System, and NCSI NaviGate Mitral) are emerging because valve replacement might be more durable compared with valve repair. In small studies, these interventional therapies demonstrated feasibility and efficiency to reduce MR and to improve heart failure symptoms. However, neither transcatheter nor surgical mitral valve repair or replacement has been proven to impact on the prognosis of heart failure patients with severe MR, which remains high with a mortality rate of 14–20% at 1 year. To date, the primary indication for treatment of secondary severe MR is the amelioration of symptoms, reinforcing the value of a Heart Team discussion. Randomized studies to investigate the treatment effect and long‐term outcome for any transcatheter or surgical mitral valve intervention compared with optimized medical treatment are urgently needed and underway.

Mitral valve pressure gradient after percutaneous mitral valve repair: every beat counts

A patient presented with symptoms of decompensated heart failure 2 months after percutaneous mitral valve (MV) repair. Echocardiography demonstrated impaired left ventricular function with elevated MV pressure gradients and pulmonary pressures during rapid atrial fibrillation. Heart rate control was achieved by implantation of a biventricular pacemaker with subsequent His‐bundle ablation because atrial fibrillation was refractory to medical treatment. During biventricular pacing at different rates (50–110 b.p.m.), heart rate correlated positively with both MV mean pressure gradient and global longitudinal strain and negatively with stroke volume. MV pressure gradients directly translated into elevated pulmonary pressures. Thus, rate control and biventricular pacing improved cardiac haemodynamics.