Functional impact of transmitral gradients at rest and during exercise after restrictive annuloplasty for ischemic mitral regurgitation

Predictors of mitral valve haemodynamics after mitral valve repair for degenerative mitral regurgitation

OBJECTIVE

Intraoperative predictors of functional mitral valve (MV) stenosis after surgical repair of mitral regurgitation (MR) caused by prolapse remain poorly characterised. This study evaluated the effect of annuloplasty size on postoperative MV haemodynamics during exercise and evaluated predictors of MV hemodynamics.

METHODS

104 patients were randomly assigned to leaflet resection or preservation for surgical repair of MR in the Canadian Mitral Research Alliance CardioLink-2 study. In this post hoc analysis, we compared MV haemodynamics between the two surgical groups and examined the relationship between annuloplasty size and MV haemodynamics 1 year after repair in the combined groups. Echocardiograms were performed at baseline and intraoperatively. Exercise transthoracic echocardiography was performed 1 year postoperatively. Multivariable linear regression analysis was used to identify predictors of exercise MV gradients at follow-up.

RESULTS

Mean age of participants was 65±10 years, and 83% were male. Median annuloplasty size was 34 (IQR 32-36). Dividing by the median, 48 (46%) had annuloplasty size of <34 mm and 56 (54%) had ≥34 mm. Mean and peak exercise gradients at 1 year were 11±5 mm Hg and 22±9 mm Hg in <34, and 6±3 mm Hg and 14±5 mm Hg in ≥34 (p<0.001). Rate of residual MR was similar in both groups. In multivariable analyses, annuloplasty size of ≥34 mm was associated with lower mean and peak exercise gradients at 12 months, after adjustment for repair type, age, sex, heart rate and body surface area (β -4.1, 95% CI -6 to -3, p<0.001, and β -7 95% CI -10 to -4, p<0.001, respectively). Intraoperative mean and peak MV gradients by transesophageal echocardiography independently predicted mean and peak resting and exercise gradients at follow-up (p<0.001). Similar results were obtained in both leaflet resection and preservation.

CONCLUSION

Annuloplasty size of ≥34 mm is associated with a 4 and 7 mm Hg reduction in mean and peak exercise MV gradients, respectively, 1 year post MV repair regardless of the repair strategy used. Intraoperative TEE MV gradients predict exercise MV gradients 1 year post repair.

TRIAL REGISTRATION NUMBER

NCT02552771.

Mitral stenosis in a teenager after rheumatic mitral valve regurgitation valve repair: A case report

Introduction

Mitral stenosis (MS) is a widely known complication of mitral valve repair for non-rheumatic mitral regurgitation (MR). Few reports are available on the occurrence of MS after mitral valve repair for rheumatic MR in young populations.

Case summary

A 14-year-old girl presented with orthopnea, abdominal distension, and bilateral lower-limb edema. She was cachectic, with a high-pitched holosystolic murmur best heard at the cardiac apex, bilateral basal crackles, tender hepatomegaly, pitting pedal edema, and jugular venous distension. Antistreptolysin O (ASO) titer was elevated. Transthoracic echocardiography (TTE) revealed the loss of central coaptation of the mitral valve with leaflet restriction and MR, annular dilatation of the tricuspid valve, and tricuspid regurgitation (TR). She had AHA/ACC stage D mitral and TR s. Tricuspid annuloplasty and mitral valve repair for rheumatic MR were performed using Carpentier Edwards numbers 30 and 34, respectively. Following surgery, the weight and body mass index (BMI) rapidly normalized. The patient also developed progressive MS.

Discussion

Previous studies in adults have described the etiopathogenesis of MS after non-rheumatic mitral valve repair. There is a paucity of reports describing the development of MS over the span of months after rheumatic MR valve repair in early pubescent children.

Conclusion

Growth spurts during puberty can potentially affect MR repair, as the mitral valve prosthesis based on the preoperative Body Surface Area (BSA) is outgrown. There is a need for research on planning, prognostication, and development of an optimal, individualized, and adaptable approach to MR intervention in early pubescence.

Flow adjusted transmitral pressure gradient as a modified indicator of functional mitral stenosis after repair for degenerative mitral regurgitation

Background and Aim

After repair of degenerative mitral regurgitation (DMR), the focus is on functional mitral stenosis (FMS) when there is a decline of mitral hemodynamics. Yet, the clinical impacts and a standardized definition are still undecided. Since common mitral hemodynamic parameters are influenced by transmitral flow, the aim of this study is to seek the impact of flow adjusted transmitral pressure gradient (TMPG) by left ventricular stroke volume (LVSV) on the midterm outcomes.

Methods

Three hundred one patients who had undergone isolated mitral valve repair for degenerative lesions with annuloplasty prosthesis between October 2012 and June 2019 were included. Postoperative adverse events occurred in 20 patients (6.6%). Flow adjusted TMPG was defined as TMPG/LVSV.

Results

Common mitral hemodynamic parameters were not associated with adverse events. By multivariable analysis, patients’ age, left ventricular ejection fraction (LVEF) and mean TMPG/LVSV were isolated as independent predictors (adjusted hazard ratio: 1.05, 0.95, and 1.16; p = .037, .005, and .035). Flow adjusted TMPG was significantly higher in the full ring group compared to the partial band group (0.051 mmHg/ml, [0.038–0.068] vs. 0.041 mmHg/ml, [0.031–0.056]; p < .001) and had a significantly negative correlation with the size of the annuloplasty prosthesis (r = −0.37, p < .001).

Conclusions

Conventional mitral hemodynamic parameters were not associated with adverse cardiac events after repair for DMR. Adjustment by flow has a potential to advance pressure gradient to a more sensitive indicator of FMS associated with clinical outcomes.

Effect of Mitral Valve Gradient After MitraClip on Outcomes in Secondary Mitral Regurgitation: Results From the COAPT Trial

OBJECTIVES

The authors sought to evaluate the association between mean mitral valve gradient (MVG) and clinical outcomes among patients who underwent MitraClip treatment for secondary mitral regurgitation (SMR) in the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial.

BACKGROUND

In the COAPT trial, patients with heart failure (HF) and severe SMR who remained symptomatic despite guideline-directed medical therapy had marked 2-year reductions in mortality and HF hospitalizations after treatment with MitraClip.

METHODS

MitraClip-treated patients were divided into quartiles (Q) based on discharge echocardiographic MVG (n = 250). Endpoints including all-cause mortality, HF hospitalization, and health status measures at 2 years were compared between quartiles.

RESULTS

Mean MVG after MitraClip was 2.1 ± 0.4 mm Hg, 3.0 ± 0.2 mm Hg, 4.2 ± 0.5 mm Hg, and 7.2 ± 2.0 mm Hg in Q1 (n = 63), Q2 (n = 61), Q3 (n = 62), and Q4 (n = 64), respectively. There was no difference across quartiles in the 2-year composite endpoint of all-cause mortality or HF hospitalization (43.2%, 49.2%, 40.6%, and 40.9%, respectively; p = 0.80), nor in improvements in New York Heart Association functional class, Kansas City Cardiomyopathy Questionnaire score, or 6-min walk time. Results were similar after adjustment for baseline clinical and echocardiographic characteristics, post-procedure MR grade, and number of clips (all-cause mortality or HF hospitalization Q4 [44.6%] vs. Q1 to Q3 [40.3%]; adjusted hazard ratio: 1.23, 95% confidence interval: 0.60 to 2.51; p = 0.57).

CONCLUSIONS

Among HF patients with severe SMR, higher MVGs on discharge did not adversely affect clinical outcomes following MitraClip. These findings suggest that in select patients with HF and SMR otherwise meeting the COAPT inclusion criteria, the benefits of MR reduction may outweigh the effects of mild-to-moderate mitral stenosis after MitraClip.

Lessons from reoperations for mitral stenosis after mitral valve repair

BACKGROUND

The durability of mitral valve repair (MVr) is usually defined by the absence of recurrent significant mitral regurgitation. Postrepair mitral stenosis (MS) is a less frequent and less studied mode of failure of MVr. We analyzed our experience in patients who underwent reoperation for postrepair MS to characterize mechanisms resulting in MS and to summarize reoperative surgical strategies and mid-term outcomes.

METHODS

Using a prospective database, we retrospectively analyzed data on 35 consecutive patients who underwent reoperation for symptomatic moderate to severe MS between January 1, 2011, and February 1, 2020.

RESULTS

The mean patient age was 61.4 ± 11.4 years, and 69% were female. The median annuloplasty ring size used at the initial repair was 28 mm (interquartile range, 26-30 mm). Additional repair techniques at the initial operation included leaflet resection in 12 patients (34%) and commissuroplasty or edge-to-edge repair in 6 patients (18%). At reoperation, the most common mechanism of MS was pannus ingrowth in 20 patients (57%), leaflet calcification in 12 (34%), commissural fusion in 5 (14%), and tunnel effect (functional MS) in 3 (9%). Twenty-two patients (63%) underwent valve replacement, and 13 (37%) underwent valve re-repair. In patients who underwent re-repair, annuloplasty revision was performed in all patients, with 6 patients (46%) converted from complete ring to band, 4 (11%) converted from ring to pericardial annuloplasty, 2 (6%) converted to no annuloplasty, and 1 (8%) with annuloplasty ring upsizing. There were no in-hospital or 1-year mortalities. Survival at the 5-year follow-up was 93.9%.

CONCLUSIONS

MS causing late failure of MVr is frequently associated with smaller ring sizes and inflammatory or calcific changes in the valve. Highly selected patients may be good candidates for mitral valve re-repair.

Clinical Impact of Flow Adjusted Transmitral Pressure Gradient After Surgical Annuloplasty for Functional Mitral Regurgitation

Downsizing of mitral annulus due to mitral annuloplasty for ischemic functional mitral regurgitation (FMR) raises a new issue, functional mitral stenosis (FMS), defined as a decline of mitral hemodynamics. However, common mitral hemodynamic parameters are influenced by transmitral flow, therefore, the clinical impacts are still controversial. The aim of this study is to seek mitral hemodynamic indices (including transmitlra pressure gradient [TMPG] adjusted by left ventricular stroke volume [LVSV]) relevant to the mid-term outcomes after annuloplasty for ischemic functional mitral regurgitation (FMR). This study is a retrospective evaluation of mitral valve hemodynamic status by resting echocardiogram at several weeks after surgery. Eighty-one patients underwent mitral annuloplasty for ischemic FMR between September 2012 and June 2019. Postoperative adverse events occurred in 28 patients (34.6%), and the overall 5-year freedom from adverse events rate was 55.9%. Common mitral hemodynamic parameters were not associated with adverse events, but flow adjusted TMPG can be a correlative factor. By multivariable analysis, postoperative systolic pulmonary artery pressure and peak TMPG/LVSV were detected as independent predictors (adjusted hazard ratio 1.07 and 1.08, P < 0.001 and < 0.001). Additionally, risk stratification by peak TMPG (cut-off: 10 mm Hg) and LVSV (cut-off: 35 mL/m²) reflected the mid-term outcomes, perceptively (P = 0.007). Conventional mitral hemodynamic parameters were not associated with adverse cardiac events after annuloplasty for ischemic FMR. However, flow adjusted TMPG was identfied as an independent predictor, and risk stratification by peak TMPG and LVSV reflected the mid-term outcomes, perceptively.

Persistent reduction of mitral regurgitation by implantation of a transannular mitral bridge: durability and effectiveness of the repair at 2 years-results of a prospective trial†

OBJECTIVES

Ring annuloplasty reduces the septal-lateral diameter (SLD) indirectly by circumferential annular cinching and frequently results in the recurrence of mitral regurgitation (MR) in patients with functional MR (FMR). Our goal was to report the results from the trial and the 2-year post-trial surveillance data. We evaluated whether direct reduction of the SLD with a transannular mitral bridge could achieve significant and durable MR reduction in patients with FMR.

METHODS

In a prospective trial, 34 consecutive patients with FMR had a mitral bridge implanted surgically. Primary end points were MR ≤1+ at 1, 3 and 6 months postimplant and freedom from subsequent surgical mitral valve repair or replacement.

RESULTS

Thirty-two of 34 (94.1%) patients met the primary end points with MR ≤1+ at 6 months. At 2 years, there were no strokes or device-related adverse events. At 2 years, MR was reduced from 3.32 ± 0.47 to 0.50 ± 0.83 (P ≤ 0.001) with ≤1+ MR in 33/34 patients, including 4 reinterventions for periprosthetic recurrent MR ≥3 without mitral bridge explants or conventional mitral repair or replacement. At 2 years, the mean mitral gradient was 2.15 ± 0.82 mmHg; the mitral annular SLD decreased from 40.4 ± 2.91 mm to 28.9 ± 1.55 mm (P ≤ 0.001). The left ventricular ejection fraction increased (57.9 ± 10.4-62.4 ± 9.7%; P ≤ 0.001). The New York Heart Association functional class improved (2.19 ± 0.76-1.41 ± 0.61; P ≤ 0.001).

CONCLUSIONS

The single-centre trial data indicate that direct reduction in the SLD with a mitral bridge is feasible, safe and efficacious in patients with FMR. Validation in a larger population of patients and comparison to conventional annuloplasty ring are necessary.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03511716.

Surgical intervention for ischemic mitral regurgitation: how can we achieve better outcomes?

Ischemic mitral regurgitation (MR) is a common complication of myocardial infarction. Left ventricular (LV) dysfunction and distortion of the subvalvular apparatus are the main contributors to ischemic MR. Coronary artery bypass grafting alone, mitral valve replacement, and mitral valve repair, with or without subvalvular procedures, have been performed for moderate-to-severe ischemic MR. Several randomized studies on the surgical treatment of ischemic MR have been performed; however, the optimal surgical strategy remains controversial because none have demonstrated a clear survival benefit. Since the mechanisms of ischemic MR are complex and multifactorial, comprehensive preoperative assessment of LV function and geometry (both global and regional), mitral valve configuration, viability testing, and exercise echocardiography are needed. A better understanding of this complicated disease and of the advantages and limitations of each procedure may help us devise more effective patient-specific surgical treatment strategies and achieve better outcomes.

Functional mitral stenosis following mitral valve repair

PURPOSE OF REVIEW

This review summarizes the evidence describing functional mitral stenosis (MS) following surgical mitral valve repair.

RECENT FINDINGS

Functional MS is an evolving concept and has been implicated in the repair of functional and organic mitral regurgitation. Following repair of functional mitral regurgitation, an elevation in peak transmitral gradient and pulmonary artery pressure has been observed under physiologic stress. These changes have been associated with worse functional status early after restrictive annuloplasty. Following repair of organic mitral regurgitation, functional MS has also been observed and appears associated with worse functional status late after surgery.

SUMMARY

Because repair of functional mitral regurgitation commonly involves restrictive annuloplasty, the issue of functional MS must be weighed against the benefits and durability of repair. Functional MS following repair of degenerative mitral regurgitation, however, may be modifiable. Research evaluating various repair techniques and their impact on functional MS following repair of organic is ongoing.

Predicting functional mitral stenosis after restrictive annuloplasty for ischemic mitral regurgitation

BACKGROUND

Although it has been realized that restrictive mitral valve annuloplasty (MVA) may re-sult in clinically significant functional mitral stenosis (MS), it still cannot be predicted. The purpose of this study was to identify risk factors for clinically significant functional MS following restrictive MVA surgery for chronic ischemic mitral regurgitation (CIMR).

METHODS

One hundred and fourteen patients who underwent restrictive MVA with coronary artery bypass grafting (CABG) for treatment of CIMR were retrospectively reviewed. Clinically significant functional MS was defined as resting transmitral peak pressure gradient (PPG) ≥ 13 mmHg.

RESULTS

During the follow-up period (range 6-12 months), 28 (24.56%) patients developed clinically significant functional MS. The PPG at follow-up was significantly higher than that measured in the early postoperative stage (3-5 days after surgery). Moreover, there was a linear correlation between the two measurements (r = 0.398, p < 0.001). Annuloplasty size ≤ 27 mm and early postoperative PPG ≥ 7.4 mmHg could predict clinically significant functional MS at 6-12 months postoperatively.

CONCLUSIONS

Chronic ischemic mitral regurgitation patients treated with restrictive MVA and CABG have significant increases in PPG postoperatively. Annuloplasty size ≤ 27 mm and early postopera-tive PPG ≥ 7.4 mmHg can predict clinically significant functional MS at 6-12 months after surgery.

Reference Values for Physical Stress Echocardiography in Asymptomatic Patients after Mitral Valve Repair

Background

Clinical decision-making in symptomatic patients after mitral valve (MV) repair remains challenging as echocardiographic reference values are lacking. In native MV disease intervention is recommended for mean transmitral pressure gradient (TPG) >15 mmHg or systolic pulmonary artery pressure (SPAP) >60 mmHg at peak exercise. Insight into standard stress echo parameters after MV repair may therefore aid to clinical decision-making during follow-up.

Hypothesis

Stress echocardiography derived parameters in asymptomatic patients after successful MV repair differ from current guidelines for native valves.

Material and methods

In 25 patients (NYHA I) after MV repair stress echocardiography was performed on a semi-supine bicycle. Doppler flow records and MV related hemodynamics at rest and peak were obtained. Linear regression analysis was performed for mean TPG and SPAP at peak, using predetermined variables and confounders.

Results

Mean TPG at rest (3.2 ± 1.4 mmHg) significantly increased at peak (15.0 ± 3.4 mmHg) but was always <25 mmHg. Mean SPAP at rest (21.4 ± 3.8 mmHg) significantly increased at peak (41.8 ± 8.9 mmHg) but was never >57 mmHg. Only the indexed MV ring diameter was inversely correlated to mean TPG at peak in a multivariable model.

Conclusion

In contrast to current recommendations in native MV disease, our data indicate that the standard value for mean TPG during stress echocardiography in asymptomatic patients after successful MV repair was above the guideline threshold of 15 mmHg in >50%, but always <25 mmHg. For SPAP, patients never reached the guideline cutoff (60 mmHg). Long-term follow-up data are needed to provide insight in clinical consequences. Baseline stress echocardiography may indicate individual reference values to compare with during follow-up.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT02371863?term=chamuleau+AND+Mitral&rank=1.

Relation of Residual Mitral Regurgitation Despite Elevated Mitral Gradients to Risk of Heart Failure Hospitalization After MitraClip Repair

Achieving minimal residual mitral regurgitation (MR) after percutaneous MitraClip repair is limited by iatrogenic mitral stenosis. It is unknown whether allowing moderately elevated postprocedural mean mitral gradients (MMGs) to achieve < moderate residual MR is preferable to moderate residual regurgitation. Patients with less-than-moderate residual MR but a MMG of ≥5 mm Hg (Group 1) were compared with patients with moderate residual MR (Group 2). The primary end point was heart failure hospitalization. Secondary end points included mortality, subsequent mitral valve surgery, and MR at 1 year. Seventy-eight patients were included in the study. Group 1 included 48 patients (median MMG 6, interquartile range 5-6 mm Hg). Group 2 included 30 patients (median MMG 3.5, interquartile range 2-5 mm Hg). Age, baseline MR severity, and type of MR were not different between groups. Freedom from heart failure hospitalization at 1 year was 91.2 ± 4.2% in Group 1 versus 70.8 ± 8.7% in Group 2 (p = 0.021). Achieved differences in MR reduction between groups persisted at 1 year (p = 0.007). Survival was not different (p = 0.402), and subsequent mitral valve surgery occurred in 4 of 48 (8%) and in 4 of 30 patients (13%) in Group 1 and Group 2, respectively (p = 0.476). By multivariate Cox regression analysis, less-than-moderate residual MR, despite moderately elevated mitral gradients, was associated with a hazard ratio of 0.21 (95% confidence interval 0.04 to 0.96) for subsequent heart failure hospitalization (p = 0.044). In conclusion, patients with less-than-moderate residual MR despite a MMG of ≥5 had a 79% reduction in hazard for subsequent heart failure hospitalization compared with patients with moderate residual MR.

The value of adding sub-valvular procedures for chronic ischemic mitral regurgitation surgery: a meta-analysis

Background:

The most performed repair technique for the treatment of chronic ischemic mitral regurgitation in patients referred for bypass grafting remains restricted annuloplasty. However, it is associated with a high rate of failure, especially if severe tenting exists.

Objectives:

To understand if adjunctive sub-valvular mitral procedures may provide better repair performance.

Methods:

A systematic literature review identified six studies of which five fulfilled the criteria for meta-analysis. Outcomes for a total of 404 patients (214 had adjunctive sub-valvular procedures and 190 restricted annuloplasty) were meta-analyzed using random effects modeling. Heterogeneity and subgroup sensitivity analysis were assessed. Primary endpoints were: late recurrence of moderate mitral regurgitation, left ventricle remodeling and coaptation depth at follow-up. Secondary endpoints were: early mortality, mid-term survival and operative outcomes.

Results:

Sub-valvular procedure technique was associated with a significantly lower late recurrence of mitral regurgitation (Odds ratio (OR) 0.34, 95% Confidence Interval (CI) [0.18, 0.65], p=0.0009), smaller left ventricle end-systolic diameter (Weighted Mean Difference (WMD) -4.06, 95% CI [-6.10, -2.03], p=0.0001) and reduced coaptation depth (WMD -2.36, 95% CI [-5.01, -0.71], p=0.009). These findings were consistent, even in studies that included patients at high risk for repair failure (coaptation depth >10 mm and tenting area >2.5 cm2). A low degree of heterogeneity was observed. There was no difference in terms of early mortality and mid-term survival; sub-valvular technique was associated with prolonged cardiopulmonary and cross-clamp time.

Conclusions:

Adding sub-valvular procedures when repairing ischemic chronic mitral valve regurgitation may be associated with better durability, even in the case of the presence of predictors for late failure.

Perspective:

Surgical sub-valvular adjunctive procedures have to be considered in the case of the presence of echocardiographic predictors for late failure.

A Comparison of 2 Mitral Annuloplasty Rings for Severe Ischemic Mitral Regurgitation: Clinical and Echocardiographic Outcomes

Controversies regarding the choice of annuloplasty rings for treatment of ischemic mitral regurgitation still exist. Aim of the study is to compare early performance of 2 different rings in terms of rest and exercise echocardiographic parameters (transmitral gradient, systolic pulmonary artery pressure, and mitral valve area), clinical outcomes, and recurrence of mitral regurgitation. From January 2008 till December 2013, prospectively collected data of patients who underwent coronary artery bypass grafting and undersizing mitral valve annuloplasty for severe chronic ischemic mitral regurgitation at our Institution were reviewed. A total of 93 patients were identified; among them 44 had semirigid Memo 3D ring implanted (group A) whereas 49 had a rigid profile 3D ring (group B). At 6 months, recurrent ischemic mitral regurgitation, equal or more than moderate, was observed in 4 and 6 patients in the group A and B, respectively (P = 0.74). Group A showed certain improved valve geometric parameters such as posterior leaflet angle, tenting area, and coaptation depth. Transmitral gradient was significantly higher at rest in the group B (P < 0.0001). During exercise, significant increase of transmitral gradient and systolic pulmonary artery pressure was observed in group B (P < 0.0001). Mitral valve area was not statistically significantly smaller at rest in between groups (P = 0.09); however, it significantly decreased with exercise in group B (P = 0.01). At midterm follow-up, patients in group B were more symptomatic. In patients with chronic ischemic mitral regurgitation, use of semirigid Memo 3D ring when compared to the rigid Profile 3D may be associated with early improved mitral valve geometrical conformation and hemodynamic profile, particularly during exercise. No difference was observed between both groups in recurrent mitral regurgitation.

Mitral Valve Stenosis after Open Repair Surgery for Non-rheumatic Mitral Valve Regurgitation: A Review

Mitral stenosis (MS) after mitral valve (MV) repair is a slowly progressive condition, usually detected many years after the index MV surgery. It is defined as a mean transmitral pressure gradient (TMPG) >5 mmHg or a mitral valve area (MVA) <1.5 cm(2). Pannus formation around the mitral annulus or extending to the mitral leaflets is suggested as the main mechanism for developing delayed MS after MV repair. On the other hand, early stenosis is thought to be a direct result of an undersized annuloplasty ring. Furthermore, in MS following ischemic mitral regurgitation (MR) repair, subvalvular tethering is the hypothesized pathophysiology. MS after MV repair has an incidence of 9-54%. Several factors have been associated with a higher risk for developing MS after MV repair, including the use of flexible Duran annuloplasty rings versus rigid Carpentier-Edwards rings, complete annuloplasty rings versus partial bands, small versus large anterior leaflet opening angle, and anterior leaflet tip opening length. Intraoperative echocardiography can measure the anterior leaflet opening angle, the anterior leaflet tip opening dimension, the MVA and the mean TMPG, and may help identify patients at risk for developing MS after MV repair.

Mitral valve area during exercise after restrictive mitral valve annuloplasty: importance of diastolic anterior leaflet tethering

BACKGROUND

Restrictive mitral valve annuloplasty (RMA) for secondary mitral regurgitation might cause functional mitral stenosis, yet its clinical impact and underlying pathophysiological mechanisms remain debated.

OBJECTIVES

The purpose of our study was to assess the hemodynamic and clinical impact of effective orifice area (EOA) after RMA and its relationship with diastolic anterior leaflet (AL) tethering at rest and during exercise.

METHODS

Consecutive RMA patients (n = 39) underwent a symptom-limited supine bicycle exercise test with Doppler echocardiography and respiratory gas analysis. EOA, transmitral flow rate, mean transmitral gradient, and systolic pulmonary arterial pressure were assessed at different stages of exercise. AL opening angles were measured at rest and peak exercise. Mortality and heart failure readmission data were collected for at least 20 months after surgery.

RESULTS

EOA and AL opening angle were 1.5 ± 0.4 cm(2) and 68 ± 10°, respectively, at rest (r = 0.4; p = 0.014). EOA increased significantly to 2.0 ± 0.5 cm(2) at peak exercise (p < 0.001), showing an improved correlation with AL opening angle (r = 0.6; p < 0.001). Indexed EOA (EOAi) at peak exercise was an independent predictor of exercise capacity (maximal oxygen uptake, p = 0.004) and was independently associated with freedom from all-cause mortality or hospital admission for heart failure (p = 0.034). Patients with exercise EOAi <0.9 cm(2)/m(2) (n = 14) compared with ≥0.9 cm(2)/m(2) (n = 25) had a significantly worse outcome (p = 0.048). In multivariate analysis, AL opening angle at peak exercise (p = 0.037) was the strongest predictor of exercise EOAi.

CONCLUSIONS

In RMA patients, EOA increases during exercise despite fixed annular size. Diastolic AL tethering plays a key role in this dynamic process, with increasing AL opening during exercise being associated with higher exercise EOA. EOAi at peak exercise is a strong and independent predictor of exercise capacity and is associated with clinical outcome. Our findings stress the importance of maximizing AL opening by targeting the subvalvular apparatus in future repair algorithms for secondary mitral regurgitation.