Reverse remodeling of tricuspid valve morphology and function in chronic thromboembolic pulmonary hypertension patients following pulmonary thromboendarterectomy: a cardiac magnetic resonance imaging and invasive hemodynamic study.

BACKGROUND: To investigate changes in tricuspid annulus (TA) and tricuspid valve (TV) morphology among chronic thromboembolic pulmonary hypertension (CTEPH) patients before and 12 months after pulmonary thromboendarterectomy (PEA) and compare these findings to normal control subjects. METHODS: 20 CTEPH patients and 20 controls were enrolled in the study. The patients were examined with echocardiography, right heart catherization and cardiac magnetic resonance imaging prior to PEA and 12 months after. RESULTS: Right atrium (RA) volume was significantly reduced from baseline to 12 months after PEA (30 ± 9 vs 23 ± 5 ml/m2, p < 0.005). TA annular area in systole remained unchanged (p = 0.11) and was comparable to controls. The leaflet area, tenting volume and tenting height in systole were significantly increased at baseline but decreased significantly with comparable values to controls after 12 months (p < 0.005). There was correlation between the changes of right ventricular-pulmonary artery coupling and changes of TV tenting height (r = - 0.54, p = 0.02), TV tenting volume (r = - 0.73, p < 0.001) and TV leaflet area (- 0.57, p = 0.01) from baseline to 12 months after PEA. Tricuspid regurgitation jet area/RA area was significantly (p < 0.01) reduced from baseline (30 ± 13%) to 12 months after PEA (9 ± 10%). CONCLUSION: In CTEPH patients selected for PEA, TV tenting height, volume and valve area are significantly increased whereas annulus size and shape are less affected. The alterations in TV morphology are fully reversed after PEA and correlates to improvements of right ventricular-pulmonary arterial coupling.

Long-term changes of resting and exercise right ventricular systolic performance in patients with chronic thromboembolic pulmonary hypertension following pulmonary thromboendarterectomy - A two-dimensional and three-dimensional echocardiographic study.

AIMS: To characterize right ventricular (RV) geometry and function in chronic thromboembolic pulmonary hypertension (CTEPH) patients at rest and during exercise before pulmonary thromboendarterectomy (PEA), and at 3 and 12 months after PEA using two-dimensional and three-dimensional echocardiography with reference to clinical performance and exercise capacity. METHODS AND RESULTS: Forty subjects (20 CTEPH patients and 20 controls) were enrolled between December 2014 and January 2017. Three-dimensional echocardiography demonstrated a significant reduction and normalization of end-diastolic and end-systolic RV volumes in CTEPH patients 12 months after PEA. RV systolic function improved after PEA; however, tricuspid annular plane systolic excursion (TAPSE) (baseline 18 ± 6 mm vs 15 ± 3 mm at 12 months after PEA, P < .05) and tricuspid lateral annular systolic velocity (RV-S') (baseline -8.3 ± 2.1 cm/s vs -7.2 ± 1.3 cm/s at 12 months after PEA, P < .05) declined significantly after PEA. Tricuspid regurgitation gradient was 64 ± 21 mm Hg at baseline, 40 ± 14 mm Hg at 3 months, and 30 ± 13 at 12 months, P < .00001. RV free-wall longitudinal strain at peak exercise was significantly increased from baseline (-10.6 ± 5.5%) to 12 months of follow-up (-15.8 ± 5.2%), P < .005. Physical exercise capacity, measured as peak oxygen uptake, was significantly increased and correlated directly with improvement of resting and exercise-induced RV-EF. CONCLUSION: Improvement of RV geometry and systolic function, along with the reduction of systolic pulmonary pressure, can be expected following PEA in CTEPH patients during long-term follow-up. Improvement of RV myocardial contractility after PEA was only revealed at peak exercise over time. Importantly, physical exercise capacity was significantly increased and was found to be directly correlated with improvement of resting and exercise-induced RV-EF.

Current status of transcatheter mitral valve repair therapies - From surgical concepts towards future directions.

Transcatheter mitral valve (MV) intervention has emerged as an effective treatment option for symptomatic severe mitral regurgitation (MR) in patients considered to be inoperable or at high operative risk for surgical MV surgery. In primary mitral regurgitation, surgical repair is the standard of care. Transcatheter edge-to-edge MV repair with the MitraClip system has the largest clinical experience to date and offers a sustained clinical benefit in selected surgical high-risk patients. Surgery for secondary MR remains a challenge. Indications and the preferred surgical procedure remain controversial, mainly because of high recurrence rate of MR and the absence of evidence for survival benefit after surgery. Secondary MR is currently the most common indication for MitraClip use in Europe. Many registries show the safety of this procedure and improvements in patient symptoms and quality of life after 1 year, but most patients still have considerable residual MR. Other transcatheter MV repair devices are still in their early experiences. However, durability, safety, and possible damage of adjacent cardiac structures remain important concerns. Future directions for treatment of patients with secondary MR will depend on outcomes from the clinical trials in progress, whatever the use of transcatheter techniques is expected to expand substantially in the next years. This review aims to provide an overview of transcatheter MV interventions, emerging from surgical concepts, including leaflet repair, chordal replacement, and annuloplasty, and to discuss the challenges they face and future directions in achieving successful clinical application.

Comparison of aortic valve repair techniques with single- and double-ring annuloplasties.

OBJECTIVES: For patients with isolated aortic regurgitation, a double sub- and supravalvular annuloplasty has been shown to reduce recurrent aortic regurgitation after aortic valve repair compared with a single subvalvular annuloplasty. The objective of this study was to compare the geometrical and dynamic properties of single- and double-ring annuloplasties in an in vitro model. METHODS: Eighteen aortic roots from 80 kg pigs were randomized into a control, single-ring and double-ring group. Experiments were conducted in a pulsatile in vitro model. Hydrodynamics, radial force measurements at annular and sinotubular level and 2D echographic imaging were obtained. RESULTS: Both the single- and double-ring annuloplasties downsized the aortic annulus and sinotubular junction (STJ) significantly and increased the coaptation height. The double-ring annuloplasty showed an additional significant increase in coaptation height compared with the single ring [8.5 (0.9)-9.8 (0.8) mm, P < 0.01]. The single-ring annuloplasty reduced radial forces at both levels, whereas the double-ring annuloplasty showed the greatest force reduction of the STJ. CONCLUSIONS: By treating the whole functional aortic annulus, encompassing both the aortic annulus and the STJ, a greater force reduction is observed. A subvalvular annuloplasty alone is efficient in reducing aortic annulus diameter and increasing coaptation height, however, by treating the STJ as well, an additional effect is observed on coaptation height, creating a more efficient stabilization. Reduction of annular force-distensibility ratio with the double-ring annuloplasty compared with the native controls indicates a sustained stabilizing effect.

Long-term changes of exercise hemodynamics and physical capacity in chronic thromboembolic pulmonary hypertension after pulmonary thromboendarterectomy.

BACKGROUND: A substantial number of chronic thromboembolic pulmonary hypertension (CTEPH) patients experience dyspnea on exertion and limited exercise capacity despite surgically successful pulmonary endarterectomy (PEA). We sought to prospectively evaluate resting and peak exercise hemodynamics before, 3 and 12 months after PEA in consecutive CTEPH-patients and correlate it to physical functional capacity. METHODS AND RESULTS: Twenty consecutive CTEPH-patients were examined. Twelve months after PEA, 75% of patients with severely increased pre-PEA mean pulmonary arterial pressure (mPAP) at rest had normal or mildly increased mPAP. However, mPAP reduction was less pronounced during exercise where only 45% had normal or mildly increased mPAP at 12 months. Hemodynamic changes during exercise were tested using the pressure-flow relationship (i.e. mPAP/cardiac output (CO) slope). The average mPAP/CO slope was 7.5 ± 4.2 mm Hg/L/min preoperatively and 3.9 ± 3.0 mm Hg/L/min at 12 months (p < .005). CO reserve (CO increase from rest to peak exercise) was increased (5.7 ± 2.9 L/min) 12 months after PEA compared with pre-PEA (2.5 ± 1.8 L/min), p < .0001. However, 12 months after PEA, the CO reserve was only 49% of that of healthy controls, p < .0001. Changes in cardiac output (∆CO), calculated as the difference between CO before PEA and 12 months later, were significantly correlated with six-minute-walk-test and peak oxygen uptake (VO2), both at rest and peak exercise. CONCLUSION: Invasive exercise hemodynamic examination in CTEPH-patients demonstrates that after otherwise successful PEA surgery, >50% of patients have a significant increase in exercise mPAP, and the CO reserve remains compromised 12 months after PEA. Improvement in physical capacity is correlated with ∆CO.

Long-term changes of right ventricular myocardial deformation and remodeling studied by cardiac magnetic resonance imaging in patients with chronic thromboembolic pulmonary hypertension following pulmonary thromboendarterectomy.

BACKGROUND: Right ventricular (RV) afterload in patients with chronic thromboembolic pulmonary hypertension (CTEPH) is associated with reduced myocardial contractility and ventriculoarterial coupling. The impact of increased afterload on RV myocardial deformation was assessed by comparing the characteristics of CTEPH patients to healthy controls at baseline, and by comparing characteristics of CTEPH patients before and 12 months after pulmonary endarterectomy (PEA). METHODS: Cardiac deformation and function of CTEPH patients (n = 20) and healthy controls (n = 20) were assessed by cardiac magnetic resonance (CMR). CTEPH patients were also examined with right heart catheterization before and 12 months after PEA. RESULTS: PEA resulted in significant improvement of invasive hemodynamics and normalization of RV hypertrophy and right atrial, RV and left ventricular dimensions and volumes. RV ejection fraction improved from 30 ±â€¯13% at baseline to 44 ±â€¯10% at 12 months (p < 0.0001) but remained decreased compared with control subjects (54 ±â€¯4%, p < 0.05). RV global circumferential strain (GCS) normalized 12 months after PEA, but RV global longitudinal strain (GLS) remained significantly lower in CTEPH patients than controls (baseline -12.9 ±â€¯3.3% vs. -16.5 ±â€¯3.6% at 12 months p < 0.01, vs. controls -19.3 ±â€¯3.2%, p < 0.05). RV mass changes were significantly correlated with RV-ejection fraction, RV-GLS, and RV-GCS. RV-pulmonary arterial coupling with the volume method improved at 12 months (0.49 ±â€¯0.30 vs. 0.84 ±â€¯0.31, p < 0.0005), but remained significantly reduced compared with healthy controls (1.19 ±â€¯0.20, p < 0.0005). CONCLUSION: RV global longitudinal and circumferential myocardial three-dimensional strain by CMR improved significantly in CTEPH patients 12 months after PEA. Improvements in myocardial deformation were associated with regression of RV hypertrophy and decrease in pulmonary artery pressure.

Altered stresses and dynamics after single and double annuloplasty ring for aortic valve repair.

OBJECTIVES: Aortic valve repair procedures for the treatment of isolated aortic valve insufficiency may be improved by stabilizing the functional aortic annulus using a double annuloplasty ring at the aortic annulus and sinotubular junction (STJ). The objective of this study was to compare the geometrical changes and aortic root stress distribution when using a single subvalvular ring and a double sub- and supravalvular ring in vivo. METHODS: Both the single- and double-ring procedures were performed successively in nine 80-kg pigs. Measurements were performed intraoperatively using sonomicrometry crystals in the aortic root to evaluate geometrical changes and annular and STJ force transducers measuring the segmental radial stress distribution. RESULTS: The total force in the STJ was significantly reduced after the double-ring procedure from 1.7 ± 0.6 to 0.04 ± 1.1 N (P = 0.001). The double-ring procedure significantly reduced the STJ area from 234.8 ± 37.6 to 147.5 ± 31.8 mm2 (P = 0.001) and expansibility from 17 ± 6% to 8 ± 3% (P = 0.001). With the single-ring procedure, the STJ shape was circular but became more oval with the double-ring procedure. The double-ring procedure did not affect stress distribution or geometry in the aortic annulus. CONCLUSIONS: The double-ring procedure stabilized the whole aortic root by reducing radial stress distribution in the STJ more efficiently than the single-ring procedure. Both area and expansibility were reduced with the double-ring procedure. These results confirm the importance of addressing the entire functional aortic annulus for optimal aortic valve repair procedures.

The prevalence of moderate mitral regurgitation in patients undergoing CABG.

OBJECTIVE: The aim of this study was to determine the prevalence of moderate ischemic mitral regurgitation (IMR) in the contemporary CABG population. We also aimed to correlate the effective regurgitant orifice area (ERO) of any regurgitant mitral valve in patients with coronary artery disease with the semiquantitative integrated scale of IMR. DESIGN: From March 15 through June 15, 2006, 510 consecutive CABG patients in three tertiary centres were included in the study. All patients showing any sign of mitral regurgitation (MR) at the referring hospital underwent a preoperative transthoracic echocardiographic estimation of the degree of MR using the integrated scale (1-4) and ERO. RESULTS: IMR was found in 141 patients (28%). The prevalence of moderate 2+ or worse IMR was 4% (95% CI; 2.5-6.1%) and the ERO corresponding to 2+ IMR or more ranged from 5 to 30 mm(2). Fourteen patients had an ERO between 15-30 mm(2). CONCLUSIONS: According to our study, patients with moderate IMR, defined as an ERO between 15-30 mm(2), account for only 2.7% (95% CI; 1.5-4.7%) of a non-emergency CABG population.

A catheter based chronic porcine model of post-infarct dilated heart failure.

OBJECTIVES: New surgical treatments for post-infarct antero-septal myocardial akinesia have been developed but evaluation of their mode of function is hampered by absence of suitable large animal heart failure models. We aimed to develop and evaluate a human compatible model for chronic post-infarct left ventricular (LV) remodeling. DESIGN: Fourteen female 50 kg pigs underwent catheter-based coronary artery occlusion (one hour) distal to the first LAD diagonal. Eight weight- and age-matched healthy animals served as controls. LV geometry and function were assessed after 6 weeks with cardiovascular MRI. RESULTS: All animals recovered from interventions. Three animals died during follow-up. All intervention animals had antero-septal akinetic infarcts (mean 26.5% of LV myocardium). Intervention animals had significantly increased end-diastolic and end-systolic volumes, and decreased stroke volume, ejection fraction and cardiac output. Detailed functional analysis showed significant systolic- and diastolic-dysfunction in intervention animals. CONCLUSIONS: We have established a feasible model of post-infarct LV remodeling, which accurately simulates human pathogenesis and pathophysiology. The model may be suitable for evaluation of novel surgical alleviations for heart failure.

Moderate mitral regurgitation in patients undergoing CABG--the MoMIC trial.

BACKGROUND: The presence of mild to moderate ischemic mitral regurgitation (IMR) marks a significantly reduced long-term survival and increased hospitalizations due to heart-failure. However, it is common practice in many institutions to refrain from repairing the mitral valve in these patients. There are no available conclusive data to support this practice, and thus there is a need for an adequately powered randomized trial. STUDY DESIGN: The Moderate Mitral Regurgitation In Patients Undergoing CABG (MoMIC) trial is the first international multi-center, large-scale study to clarify whether moderate IMR in CABG patients should be corrected. A total of 550 CABG patients with moderate IMR are to be randomized to treatment of either CABG alone or CABG plus mitral valve correction. The primary end point is a composite end point of mortality and rehospitalization for heart failure at five years. The inclusion and randomization of patients started in February 2008. IMPLICATION: If correction of moderate IMR in CABG patients proves to be the superior strategy, most patients should be treated accordingly.

Comparison of Dacron ring and suture annuloplasty for aortic valve repair-a porcine study.

BACKGROUND: A subvalvular annuloplasty is often used for aortic valve repair in patients with isolated aortic regurgitation with aortic annulus dilatation. Our aim was to characterize and compare annulus geometry and dynamics of the Dacron ring and suture annuloplasty and compare it with the native aortic annulus under standardized conditions. METHODS: We randomized 29 pigs of 80 kg into a Dacron ring group, a suture annuloplasty group and a native control group. The assessment was performed using sonomicrometry crystals for evaluation of dynamic geometry, and pressure measurements and echocardiography to evaluate valve performance. RESULTS: Aortic annulus area (AAA) was significantly reduced in the Dacron and Suture group compared with the Native group. Expansibility was similar and within normal physiologic limits in all three groups (Native: 12%±7%; Dacron: 11%±3%; Suture: 10%±4%). The largest segmental expansion was observed at the right coronary sinus (RC) in the Native and Dacron group but in the Suture group there was no significant difference between segments. The aortic annulus was primarily oval in systole and became more circular in diastole in the Native and Dacron group, however, in the Suture group, the sphericity remained relatively unchanged throughout the cardiac cycle. CONCLUSIONS: This study is the first to describe and compare detailed segmental geometry of the Dacron ring and suture annuloplasty in a standardized porcine model. The two annuloplasties effectively downsized the aortic annulus, while expansibility was maintained. Each annuloplasty had its own geometrical characteristics, but the Dacron ring was more similar to the native aortic annulus than the suture annuloplasty. This study suggests that the Dacron ring offers a more physiological and standardized support by mimicking the geometry and dynamics of the native aortic annulus and thus is a preferable choice over the suture annuloplasty for valve-sparing aortic root procedures.

Asymmetric Dynamics of the Native Aortic Annulus Evaluated by Force Transducer and Sonomicrometry in a Porcine Model.

PURPOSE: With new repair techniques of the aortic root and valve emerging, a detailed understanding of the dynamics of the aortic annulus and valve is required for optimal results. The objective of this study was to characterize geometrical changes and force distribution of the native porcine aortic annulus throughout the cardiac cycle. METHODS: Measurements were performed in an acute 80 kg porcine model (n = 7) using sonomicrometry crystals in the aortic annulus for evaluation of geometry and dynamics, annular force transducer evaluating force distribution, and pressure measurements and echocardiography evaluating valve performance. RESULTS: Overall, segmental force distribution and geometrical changes differed between different segments of the aortic annulus. The highest force development was found at the left/right interleaflet triangle (2.87 ± 2.1 N) and the largest segmental expansion was observed at the right-coronary and left-coronary sinus. The aortic annulus changed configuration throughout the cardiac cycle and became more oval in systole. CONCLUSIONS: This study is the first to describe detailed segmental dynamics and force distribution of the native aortic annulus in a porcine model in vivo. The heterogenous behavior of the aortic annulus suggests that different segments demand different support for repair of the aortic root and valve.

Chronic ischemic mitral regurgitation induced in pigs by catheter-based coronary artery occlusion.

BACKGROUND AND AIM OF THE STUDY: Ischemic mitral regurgitation (IMR) appears in 20-50% of patients after acute myocardial infarction, and entails an increased long-term mortality. In order to compensate for the diversified pathology in humans, this disease entity has been developed in pigs in order to allow investigations of therapeutic options against IMR. METHODS: The left circumflex coronary artery was occluded using catheter-based intracoronary coil deployment in 24 female pigs (body weight 50 kg). This was followed by a rapid pacing protocol. The left ventricular (LV) volumes at end-diastole and end-systole were assessed with multi-slice, short-axis cardiovascular magnetic resonance imaging. From these image sequences the mitral regurgitant volume (MRV) was quantified by subtracting the aortic flow volume from the LV stroke volume. The extension of myocardial infarction was quantified using a delayed contrast (gadolinium) enhancement technique. Five pigs served as controls. RESULTS: During the procedure, seven animals died due to intractable ventricular fibrillation and technical problems. Eleven of the remaining 17 pigs fitted with coils survived the six-week follow up period. Of these animals, nine had a transmural inferior-lateral LV wall infarction and significant IMR (MRV = 10.5 +/- 6.3 ml). None of the control pigs had IMR. There was a positive correlation between the size of the myocardial infarction and the mitral regurgitant volume. CONCLUSION: A catheter-based porcine model has been established for chronic IMR which balances between an adequate infarct size and acceptable mortality. The model provides a platform for further investigations of the geometric and hemodynamic features of chronic IMR in order to identify potential geometric targets of the disease. The model also allows the evaluation of innovative surgical approaches to reverse LV remodeling.

Semi-rigid mitral annuloplasty rings improve myocardial stress adaptation compared to rigid rings: insights from in vitro and in vivo experimental evaluation.

OBJECTIVES: Investigate myocardial stress adaptation and remodelling capacity of a rigid and semi-rigid mitral annuloplasty ring. METHODS: The annuloplasty rings were characterized in vitro in a mechanical setup with tensile and compressive forces from 0 to 3 N. The rings were tested with and without fixation of the ring to imitate the effect of annular implantation. In vivo measurements were performed with 21 porcine animals randomized into: A no ring group, a rigid ring group (Classic Annuloplasty Ring TM , Edwards Lifesciences) and a semi-rigid ring group (Physio I Annuloplasty Ring, Edwards Lifesciences). The rings were implanted together with a force transducer and sonomicrometry was used for geometry measurements. RESULTS: The flexibility range of the semi-rigid ring was 7.6 and 2.4 mm in the septal-lateral and commissural direction, respectively. With fixation the flexibility was reduced to 1.0 and 0.6 mm, similar to the rigid ring without fixation. In vivo measurements indicated that the rigid and semi-rigid rings equally restrict the annular movement. Septal-lateral flexibility of the semi-rigid ring was not observed. Both rings induced force absorption in the ring and sutures due to the annular fixation. The absorbed forces were significantly lower for the semi-rigid ring in the posterior segment and septal-lateral direction. CONCLUSIONS: This study demonstrates the importance of correct fixation when characterizing annuloplasty rings. The annular movement of the semi-rigid ring was similar to the rigid ring when implanted at the mitral annulus as confirmed in vitro . Despite this the semi-rigid ring demonstrated a favourable stress adaptation which could potentially decrease the risk of ring dehiscence.

The effect of different mitral annuloplasty rings on valve geometry and annular stress distribution†.

OBJECTIVES: To characterize the remodelling effects and deformational forces of normosized rigid, semirigid and flexible mitral annuloplasty rings after implantation in healthy pigs. METHODS: Measurements were performed in vivo with 80-kg porcine animals. Twenty-eight animals were randomized into a no ring group, a flexible ring group (Duran AnCore Ring, Medtronic, Minneapolis, MN, USA), a rigid ring group (Carpentier-Edwards Classic annuloplasty ring, Edwards Lifesciences, Irvine, CA, USA) and a semirigid ring group (Carpentier-Edwards Physio I annuloplasty ring, Edwards Lifesciences). Sonomicrometry crystals were implanted together with an annuloplasty ring and a dedicated mitral annular force transducer. The mitral annuloplasty rings were compared with respect to annular geometry and mitral annular forces. RESULTS: Cyclic changes in the mitral annulus (MA) circumference were significantly lower for all ring groups (flexible: 7 ± 3 mm, semirigid: 4 ± 2 mm and rigid: 2 ± 1 mm) compared to the no ring group (11 ± 5 mm), implying the remodelling capacity of all annuloplasty rings. The cyclic change of the MA area and the septa-lateral and inter-commissural distances were equal in the semirigid and rigid ring groups and significantly lower compared to the no ring and flexible ring groups, suggesting a stronger and equal remodelling effect in the semirigid and rigid ring groups. Forces measured in the transducer reflected the remodelling capacity of the annuloplasty rings and were in general lower for the semirigid and rigid ring groups compared to the no ring and flexible ring groups. Especially the forces in the inter-commissural direction were significantly reduced for the semirigid and rigid ring groups (semi-rigid: 1.4 ± 0.8 N, rigid: 1.2 ± 0.8 N) compared to the no ring and flexible ring groups (no ring: 3.0 ± 1.1 N, flexible: 3.4 ± 1.6 N). CONCLUSIONS: This study is the first to describe different remodelling effects and deformational forces of normosized mitral annuloplasty rings in vivo . Insights into the relationship between the remodelling effects and the accumulated forces of different mitral annuloplasty rings may have implications for ring selections in an aetiology-based mitral valve repair strategy. We propose the application of such a biomechanical approach for quantitative comparison of mitral annuloplasty rings and for future innovations on a rational basis.

Perforation of the Anterior Mitral Leaflet After Impella LP 5.0 Therapy in Cardiogenic Shock.

A 52-year old man was admitted with out-of-hospital cardiac arrest, and he was resuscitated after 100 minutes. The initial hemodynamic condition was critical due to cardiogenic shock (left ventricular ejection fraction 10 % and mean arterial pressure 60 mmHg on inotropics). Acute coronary angiography did not reveal any new lesions. Due to persistent hemodynamic instability, mechanical support with Impella LP 5.0 was decided. The surgical procedure guided by fluoroscopy and transesophageal echocardiography was uncomplicated. The hemodynamic improved subsequently and after 17 days of intensive care, and additional 30 days of hospitalization, the patient was ready for discharge. Routine echocardiography prior to discharge revealed severe mitral regurgitation due to perforation of anterior mitral leaflet, a finding not observed in the previous echocardiograms. The patient was discharged to close follow up of the severe mitral regurgitation and future surgical intervention is likely. Therefore, close monitoring of mitral valve is necessary and explanation may be required if valve dysfunction is observed, as repositioning of the Impella system is not possible.

Durability after aortic valve replacement with the Mitroflow versus the Perimount pericardial bioprosthesis: a single-centre experience in 2393 patients.

OBJECTIVES: This study compares the durability and risk of reoperation in patients undergoing aortic valve replacement (AVR) with either a Mitroflow or a Carpentier-Edwards (CE) pericardial bioprosthesis. Since AVR with bioprosthetic valves has increased progressively in recent years as compared to mechanical valves, especially in patients aged 60-70 years, there has been renewed interest in the long-term durability of current pericardial bioprostheses. METHODS: We compared 440 AVR with Mitroflow valves with 1953 AVR with CE pericardial valves implanted from 1999 to 2014 with regard to reoperation, reoperation for structural valve deterioration (SVD) and all-cause mortality. RESULTS: Ten-year freedom from explant of any cause was higher for CE Perimount (98 ± 0.7%) than for Mitroflow (95 ± 1.4%, P < 0.01). Reasons for explant for CE Perimount were SVD (n = 2), endocarditis (n = 8) and paraprosthetic leak (n = 10). The reasons for explant for Mitroflow were SVD (n = 11), endocarditis (n = 3) SVD and pericarditis (n = 1) and paraprosthetic leak (n = 2). Ten-year freedom from explant due to SVD was higher for CE Perimount (100%) than for Mitroflow (96%) (P < 0.01). In small aortic annuli (bioprosthesis size 19-21 mm), freedom from SVD at 10 years for CE Perimount and Mitroflow was 100 versus 96%, respectively. By multivariate analysis, it was found that bioprosthesis size was not a risk factor for SVD. The choice of valve type could not be demonstrated to influence long-term survival. CONCLUSIONS: The Mitroflow pericardial bioprosthesis provides less than optimal mid- and long-term durability compared with the CE Perimount pericardial valve, especially for small aortic diameter implants (19 and 21 mm). This study hereby confirms the existence of a real risk of valvular deterioration of the Mitroflow valve that might compromise the prognosis of the patients.

New mitral annular force transducer optimized to distinguish annular segments and multi-plane forces.

Limited knowledge exists about the forces acting on mitral valve annuloplasty repair devices. The aim of this study was to develop a new mitral annular force transducer to measure the forces acting on clinically used mitral valve annuloplasty devices. The design of an X-shaped transducer in the present study was optimized for simultaneous in- and out-of-plane force measurements. Each arm was mounted with strain gauges on four circumferential elements to measure out-of-plane forces, and the central parts of the X-arms were mounted with two strain gauges to measure in-plane forces. A dedicated calibration setup was developed to calibrate isolated forces with tension and compression for in- and out-of-plane measurements. With this setup, it was possible with linear equations to isolate and distinguish measured forces between the two planes and minimize transducer arm crosstalk. An in-vitro test was performed to verify the crosstalk elimination method and the assumptions behind it. The force transducer was implanted and evaluated in an 80kg porcine in-vivo model. Following crosstalk elimination, in-plane systolic force accumulation was found to be in average 4.0±0.1N and the out-of-plane annular segments experienced an average force of 1.4±0.4N. Directions of the systolic out-of-plane forces indicated movements towards a saddle shaped annulus, and the transducer was able to measure independent directional forces in individual annular segments. Further measurements with the new transducer coupled with clinical annuloplasty rings will provide a detailed insight into the biomechanical dynamics of these devices.

Influence of anterior mitral leaflet second-order chordae tendineae on left ventricular systolic function.

BACKGROUND: The contribution of anterior mitral leaflet second-order ("strut") chordae tendineae to left ventricular (LV) systolic mechanics is debated; we measured the in vivo contribution of anterior chordae tendineae (ACT) and posterior chordae tendineae (PCT) to regional and global LV contractile function. METHODS AND RESULTS: Eight sheep had radiopaque markers implanted in the LV epicardium, partitioning the ventricle into 12 regions. Microminiature force transducers and snares were sutured to anterior leaflet "strut" chordae originating from ACT and PCT papillary muscles. Chordal tension, marker images, and hemodynamic data were acquired before and after (CUT) severing ACT and PCT. Fractional area shrinkage and slope of the regional end-diastolic area-regional stroke work relation (r-PRSW) were computed for each LV region. CUT did not affect global LV systolic function but reduced FAS in LV segments near the PCT insertion site: equatorial posterior lateral (19+/-2% versus 16+/-2%, P<0.05), apical posterior lateral (23+/-4% versus 19+/-4%, P<0.05), and posterior medial LV segments (16+/-2% versus 13+/-2%, P<0.05). r-PRSW fell near both the ACT (equatorial anterior medial [84+/-8 versus 62+/-11 mm Hg, P<0.05] and lateral [73+/-7 versus 53+/-9 mm Hg, P<0.05]) and PCT (apical posterior medial [91+/-12 versus 67+/-17 mm Hg, P<0.05] and lateral [72+/-8 versus 59+/-9 mm Hg, P<0.05]) LV insertion sites. Maximum tension in PCT was higher than in ACT (0.81+/-0.1 versus 0.52+/-0.08N, P<0.01). CONCLUSIONS: Dividing anterior leaflet strut chordae in sheep was associated acutely with regional LV systolic dysfunction near the chordal insertion sites. Caution is necessary when embarking on procedures that cut second-order chordae to treat ischemic mitral regurgitation, since this may compromise LV systolic function in ventricles that are already impaired.

Imbalanced chordal force distribution causes acute ischemic mitral regurgitation: mechanistic insights from chordae tendineae force measurements in pigs.

BACKGROUND: Ischemic mitral regurgitation is caused by an imbalance of the entire mitral-ventricular complex. This interaction is mediated through the chordae tendineae force distribution, which may perturb several elements of the mitral valve apparatus. Our objective was to investigate the association between the mitral valvular 3-dimensional geometric perturbations and chordae tendineae force redistribution in a porcine model of acute ischemic mitral regurgitation. METHODS: In 9 pigs, acute ischemic mitral regurgitation was induced by repeated microembolization of the left circumflex coronary artery. Mitral leaflet coaptation geometry was determined by 2-dimensional echocardiography and reconstructed 3-dimensionally. Leading edge chordal forces were measured by dedicated miniature force transducers at control and during ischemic mitral regurgitation. RESULTS: During acute ischemic mitral regurgitation, there was a decreased tension of the primary chorda from the ischemic posterior left ventricular wall to the anterior leaflet (0.295 +/- 0.063 N vs 0.336 +/- 0.071 N [control]; P < .05). The tension of the chorda from the nonischemic anterior left ventricular wall to the anterior leaflet increased (0.375 +/- 0.066 N vs 0.333 +/- 0.071 N [control]; P < .05). In accordance, relative leaflet prolapse was observed at the ischemic commissural side, whereas there was an increase in the leaflet surface area at the nonischemic commissural side, indicating localized leaflet tethering. CONCLUSIONS: Acute ischemic mitral regurgitation due to posterior left ventricular wall ischemia was associated with focal chordal and leaflet tethering at the nonischemic commissural portion of the mitral valve and a paradoxical decrease of the chordal forces and relative prolapse at the ischemic site of the anterior mitral valve leaflet.