Clinical anatomy of the coronary venous system and relevance to retrograde cardioplegia and cardiac electrophysiological interventions.

Anomalies of coronary venous system, the valve of the coronary sinus (Thebesian valve) and other cardiac malformations may make interventions through the coronary sinus difficult. These variants may pose a challenge in cannulating the coronary sinus for retrograde cardioplegia and for interventions performed through the coronary sinus by cardiac electrophysiologist/interventional cardiologist. Retrograde cardioplegia is an established method of myocardial protection with advantages, indications, and complications. A good knowledge of the anatomy of the coronary sinus and its variants is important in understanding the difficulties encountered while cannulating the coronary sinus for the delivery of retrograde cardioplegia, cardiac resynchronization therapy, treatment of arrhythmias, and percutaneous mitral valve annuloplasty.

One-Year Outcomes After MitraClip for Functional Mitral Regurgitation.

BACKGROUND: Secondary mitral regurgitation (SMR) occurs in the absence of organic mitral valve disease and may develop as the left ventricle dilates or remodels or as a result of leaflet tethering with impaired coaptation, most commonly from apical and lateral distraction of the subvalvular apparatus, with late annular dilatation. The optimal therapy for SMR is unclear. This study sought to evaluate the 1-year adjudicated outcomes of all patients with SMR undergoing the MitraClip procedure in the EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) Investigational Device Exemption program, which is comprised of the randomized clinical trial, the prospective High-Risk Registry, and the REALISM Continued Access Registry (Multicenter Study of the MitraClip System). METHODS: Patients with 3+/4+ SMR enrolled in EVEREST II were stratified by non-high surgical risk (non-HR) and high surgical risk (HR) status (defined as Society of Thoracic Surgeons risk of mortality ≥12% or predefined risk factors). Clinical, echocardiographic, and functional outcomes at 1 year were evaluated. RESULTS: A total of 616 patients (482 HR, 134 non-HR; mean age, 73.3±10.5 years; Society of Thoracic Surgeons risk, 10.2±6.9%) with SMR underwent the MitraClip procedure. At baseline, 80.5% of patients were in New York Heart Association class III/IV. Major adverse events at 30 days included death (3.6%), stroke (2.3%), and renal failure (1.5%). At discharge, 88.8% had MR ≤2+. At 1 year, there were 139 deaths, and the Kaplan-Meier estimate of freedom from mortality was 76.8%. The majority of surviving patients (84.7%) remained with MR ≤2+ and New York Heart Association class I/II (83.0%). Kaplan-Meier survival at 1 year was 74.1% in HR patients and 86.4% in non-HR patients ( P=0.0175). At 1 year, both groups achieved comparable MR reduction (MR ≤2+, 84.0% versus 87.0%) and improvement in left ventricular end-diastolic volume (-8.0 mL versus -12.7 mL), whereas New York Heart Association class I/II was found in 80.1% versus 91.8% ( P=0.008) of HR and non-HR patients, respectively. In HR patients, the annualized rate of heart failure hospitalizations decreased from 0.68 to 0.46 in the 12 months before to 12 months after the procedure ( P<0.0001). CONCLUSIONS: Transcatheter mitral valve repair with the MitraClip in patients with secondary MR is associated with acceptable safety, reduction of MR severity, symptom improvement, and positive ventricular remodeling. CLINICAL TRIAL REGISTRATION: https://www.clinicaltrials.gov . Unique identifiers: NCT00209274, NCT01940120, and NCT01931956.

Anatomical relationship between mitral valve annulus and circumflex artery and its surgical implications.

BACKGROUND: Performing surgical procedures around the mitral valve (MV) annulus can cause iatrogenic lesions on the circumflex artery (Cx). The risk of this iatrogenesis comes from the proximity between this vessel and the MV annulus. OBJECTIVE: To evaluate the relation between the MV annulus and the Cx at different spots of its path and highlight the risks of its damage. METHODS: Fifty cadaveric adult human hearts were studied. Each heart was categorized depending on coronary dominance, and Cx was classified in type 1 (Cx giving off only the left posterior ventricular artery) and type 2 (Cx reaching the crux cordis and giving off the posterior interventricular branch). Three reference spots were chosen: A- when Cx begins to run across the coronary sulcus; B- immediately before the left posterior ventricular artery emerges and C- in the midpoint of the two previous points; to measure the diameter of the Cx and the MV annulus. Values of P<0.05 were considered significant. RESULTS: A total of 43 (86%) hearts were classified in type 1. These hearts showed that the diameter of the Cx in spot A is bigger than in the B and C spots (P=0.001). The 7 hearts (14%) classified in type 2 did not exhibit a difference in the diameter of the Cx in the A, B and C spots (NS). Also, the thickness of the fibrous annulus, in type 1 and type 2 hearts were not different between the three spots (NS). CONCLUSION: The present study showed that the diameter of the Cx varies depending on the heart type. This knowledge might improve the success rate of cardiac surgeries and decrease the rates of iatrogenic Cx lesions.

[Cardioband®: Where do we stand, who are suitable patients?] / Cardioband®: Wo stehen wir, was sind geeignete Patienten?

Functional mitral regurgitation (FMR) is characterized by a dilatation of the mitral valve annulus resulting in an insufficient adaptation of the anterior and posterior mitral valve leaflets and/or severe tethering of the leaflets due to dilatation of the left ventricle. The Cardioband® system was introduced in 2015 and is a catheter-based direct mitral valve annuloplasty procedure for treatment of FMR. In the European CE approval study 60 patients with moderate or severe FMR were analyzed per protocol. There were no device or procedure-related deaths. The technical success rate of the procedure, defined as successful implantation and tightening was 97%. At 1 year, the overall survival and survival free of hospital readmission for heart failure were 87% and 66%, respectively. Currently, various interventional treatment procedures are available, such as the edge-to-edge technique as well as direct and indirect annuloplasty. In summary, patients with FMR as a result of a dilatation of the mitral valve annulus appear to be suitable for direct annuloplasty with the Cardioband® system.

Mechanical properties of a new thermally deformable mitral valve annuloplasty ring and its effects on the mitral valve.

Ideally, an annuloplasty ring's shape should be changed intraoperatively if mitral valve repair is unsuccessful because of a short coaptation length or systolic anterior motion. Several post-implantation adjustable rings have been developed, but they are not freely deformable and are unsuitable for asymmetric repair of the valvular annulus. We developed a novel thermally deformable mitral annuloplasty ring to address these problems and assessed the ring's mechanical properties and its effect on the mitral valve anatomy. This ring was made of polycaprolactone. Tensile and bending tests were performed to evaluate the ring's mechanical properties. The ratio of the transverse and septal-lateral length was determined as 4:3. Using 10 pig hearts, we measured the post-deformation coaptation length and minimum distance from the coaptation to the ventricular septum, which is a factor of abnormal systolic anterior motion of the mitral valve. In the mechanical tests, the ring's yield point was greater than the deformation force of the annulus in humans. In pigs with deformation from "4:3" to "4:2", the coaptation length was significantly increased in each mitral valve part. In pigs with deformation from "4:3" to "4:4", the minimum distance from the coaptation to the ventricular septum was significantly increased. Asymmetrical ring deformation increased the coaptation length only at the deformed area. In conclusion, this new thermally deformable mitral annuloplasty ring could be "order-made" to effectively change the coaptation length in all parts of the mitral valve and the distance from the coaptation to septum post-deformation via intraoperative heating.

Mitral valve annuloplasty versus no intervention for mild-to-moderate secondary mitral regurgitation in severe aortic regurgitation: a propensity-score matched analysis.

BACKGROUND: The management strategy for secondary mitral regurgitation (MR) during aortic valve surgery for aortic regurgitations (ARs) remains controversial. This study aimed to compare the outcomes between mitral valve annuloplasty (MVP) and no intervention for managing 2+ or 3+ MR among severe patients with AR. METHODS: Eighty-seven eligible patients with complete echocardiographic follow-up were included, with 51 patients in the MVP group and 36 in the No-MVP group. The MVP group had a larger left atrial (LA) diameter (44.2 ± 6.6 vs 49.4 ± 7.6 mm; P = .001) and a higher proportion of 3+ MR (33.3% vs 76.5%; P < .001) than the No-MVP group. After 1:1 propensity-score matching, the patients treated with and without MVP were balanced on 14 preoperative characteristics. RESULTS: There was one in-hospital death in each group. In the propensity-score matched cohort, there was no statistically significant difference between the two groups in the cumulative incidence of residual 2+ MR during a follow-up of 26.4 ± 14.8 months (P = .64). The No-MVP group was associated with a more significant change in the left ventricular end-diastolic dimension (18.1 ± 7.9 vs 13.7 ± 8.7 mm; P = .02), while the changes in the LA diameter, left ventricular end-systolic dimension, and left ventricular ejection fraction were similar between the two groups. CONCLUSIONS: The severity of MR and the LA size may impact surgeons' decisions. MVP does not seem to add extra benefits to the outcomes, and it may be associated with worse left ventricular remodeling.

Antithrombotic therapy after mitral valve repair: VKA or aspirin?

The optimal antithrombotic therapy following mitral valve repair (MVr) is still a matter of debate. Therefore, we evaluated the rate of thromboembolic and bleeding complications of two antithrombotic prevention strategies: vitamin K antagonists (VKA) versus aspirin. Consecutive patients who underwent MVr between 2004 and 2016 at three Dutch hospitals were evaluated for thromboembolic and bleeding complications during three postoperative months. The primary endpoint was the combined incidence of thromboembolic and bleeding complications to determine the net clinical benefit of VKA strategy as compared with aspirin. Secondary objectives were to evaluate both thromboembolic and bleeding rates separately and to identify predictors for both complications. A total of 469 patients were analyzed, of whom 325 patients (69%) in the VKA group and 144 patients (31%) in the aspirin group. Three months postoperatively, the cumulative incidence of the combined end point of the study was 9.2% (95%CI 6.1-12) in the VKA group and 11% (95%CI 6.0-17) in the aspirin group [adjusted hazard ratio (HR) 1.6, 95%CI 0.83-3.1]. Moreover, no significant differences were observed in thromboembolic rates (adjusted HR 0.82, 95%CI 0.16-4.2) as well as in major bleeding rates (adjusted HR 1.89, 95%CI 0.90-3.9). VKA and aspirin therapy showed a similar event rate of 10% during 3 months after MVr in patients without prior history of AF. In both treatment groups thromboembolic event rate was low and major bleeding rates were comparable. Future prospective, randomized trials are warranted to corroborate our findings.

Pulmonary arterial pressure detects functional mitral stenosis after annuloplasty for primary mitral regurgitation: An exercise stress echocardiographic study.

INTRODUCTION: The restrictive mitral valve annuloplasty (RMA) is the treatment of choice for degenerative mitral regurgitation (MR), but postoperative functional mitral stenosis remains a matter of debate. In this study, we sought to determine the impact of mitral stenosis on the functional capacity of patients. METHODS: In a cross-sectional study, 32 patients with degenerative MR who underwent RMA using a complete ring were evaluated. All participants performed treadmill exercise test and underwent echocardiographic examinations before and after exercise. RESULTS: The patients' mean age was 50.1 ± 12.5 years. After a mean follow-up of 14.1 ± 5.9 months (6-32 months), the number of patients with a mitral valve peak gradient >7.5 mm Hg, a mitral valve mean gradient >3 mm Hg, and a pulmonary arterial pressure (PAP) ≥25 mm Hg at rest were 50%, 40.6%, and 62.5%, respectively. 13 patients (40.6%) had incomplete treadmill exercise test. All hemodynamic parameters were higher at peak exercise compared with at rest levels (all P < .05). The PAP at rest and at peak exercise as well as peak transmitral gradient at peak exercise were higher in patients with incomplete exercise compared with complete exercise test (all P < .05). The PAP at rest (a sensitivity and a specificity of 84.6% and 52.6%, respectively; area under the curve [AUC] = .755) and at peak exercise (a sensitivity and a specificity of 100% and 47.4%, respectively; AUC = .755) discriminated incomplete exercise test. CONCLUSION: The RMA for degenerative MR was associated with a functional stenosis and the PAP at rest and at peak exercise discriminated low exercise capacity.

Impact of Left Ventricular to Mitral Valve Ring Mismatch on Recurrent Ischemic Mitral Regurgitation After Ring Annuloplasty.

BACKGROUND: In ischemic mitral regurgitation (IMR), ring annuloplasty is associated with a significant rate of recurrent MR. Ring size is based on intertrigonal distance without consideration of left ventricular (LV) size. However, LV size is an important determinant of mitral valve (MV) leaflet tethering before and after repair. We aimed to determine whether LV-MV ring mismatch (mismatch of LV size relative to ring size) is associated with recurrent MR in patients with IMR after restrictive ring annuloplasty. METHODS: Patients with moderate or severe IMR from the 2 Cardiothoracic Surgical Trials Network IMR trials who received MV repair were examined at 1 year after surgery. Baseline LV size was assessed by LV end-diastolic dimension and LV end-systolic dimension (LVESd). LV-MV ring mismatch was calculated as the ratio of LV to ring size (LV end-diastolic dimension/ring size and LVESd/ring size). RESULTS: At 1 year after ring annuloplasty, 45 of 214 patients with MV repair (21%) had moderate or greater MR. In univariable logistic regression analysis, larger LVESd (P=0.02) and LVESd/ring size (P=0.007) were associated with recurrent MR. In multivariable models adjusted for age, sex, baseline LV ejection fraction, and severe IMR, only LVESd/ring size (odd ratio per 0.5 increase, 2.20; 95% confidence interval, 1.05-4.62; P=0.038) remained significantly associated with 1-year MR recurrence. CONCLUSIONS: LV-MV ring size mismatch is associated with increased risk of MR recurrence. This finding may be helpful in guiding choice of ring size to prevent recurrent MR in patients undergoing MV repair and in identifying patients who may benefit from MV repair with additional subvalvular intervention or MV replacement rather than repair alone. CLINICAL TRIAL REGISTRATION: URL:http://clinicaltrials.gov. Unique identifiers: NCT00806988 and NCT00807040.