Intermediate-term outcome of mitral reconstruction in cardiomyopathy

Outcome after mitral valve operations with depressed left ventricular function

We retrospectively investigated 42 patients (27 men, 15 women; mean age, 67 years) with severe mitral valve incompetence and endstage cardiomyopathy (ejection fraction<30%) who were operated on between January 2002 and March 2009. Of these, 14 were in New York Heart Association class IV, and 27 were in class III. The etiology was ischemic in 18 patients and idiopathic dilated in 24. Mitral valve repair was performed in 25 patients, and 17 had mitral valve replacement. The mean logistic EuroSCORE was 33.41. The mean follow-up was 44.52 months. There were no perioperative deaths. Three patients died within 30 days postoperatively. Thirty-day mortality was lower than predicted by EuroSCORE (7.14% vs. 33.41%). The median functional class improved from 3 to 2 during follow-up. Ejection fraction improved from 24% to 42% at 6 weeks, then decreased to 33%. The midterm survival rate was 86%, and 81% after 1 and 2 years. Freedom from reoperation at 2 years was 85%; 6 patients needed reoperation for recurrent mitral regurgitation. Despite high operative risk, mitral valve surgery can be performed successfully with acceptably low mortality in patients with endstage cardiomyopathy. Patients experience substantial clinical improvement and a moderate recovery of left ventricular function.

Mitral valve surgery for dilated cardiomyopathy: current status and future roles

There are a large number of patients with functional mitral regurgitation resulting from dilated cardiomyopathy. The decision between surgical correction and medical management of severe mitral regurgitation in heart failure can be difficult. The data regarding long-term benefits and mortality after surgical intervention are contradictory. Recent data suggest that mitral regurgitation can be surgically corrected in heart failure with symptomatic improvements and beneficial reverse remodeling. Contrary to prior beliefs, mitral valve repair can be performed safely with minimal postoperative mortality. Data from multi-institutional, randomized prospective trials will help to elucidate many of the questions and concerns regarding repair of severe functional mitral regurgitation.

Left ventricular mechanics following restrictive mitral annuloplasty for functional mitral regurgitation: two-dimensional speckle tracking echocardiographic study

BACKGROUND

Restrictive mitral annuloplasty (RMA) is widely employed for patients with functional mitral regurgitation (MR). Its improvement of left ventricular (LV) function has been demonstrated by only a gradual increase in LV ejection fraction (EF) in the chronic phase. However, the detailed evaluation of changes in LV function has not been fully elucidated in functional MR patients before and after RMA. Therefore, we performed two-dimensional speckle tracking echocardiography (2D-STE), which enables accurate evaluation of myocardial deformation and rotation that are undetectable by conventional echocardiography.

METHODS

We studied 13 patients (mean age 61 ± 10 years) with functional MR associated with cardiomyopathy undergoing RMA. In addition to conventional echocardiographic measurements, 2D-STE was performed to measure peak systolic radial (RS), circumferential (CS), and longitudinal (LS) strains and twist before and 4 ± 2 weeks after surgery. LV twist was defined as the difference between the apical and basal rotations.

RESULTS

After RMA, EF and LS remained unchanged, but RS and CS were significantly improved at the mid-LV (RS, 20.6 ± 10.8 vs 24.5 ± 11.6%; CS, -9.6 ± 5.2 vs -12.8 ± 5.6%) and at the apex (RS, 15.0 ± 12.2 vs 18.7 ± 8.6%; CS, -4.4 ± 3.0 vs -7.8 ± 4.8%). RS and CS were unchanged at the base. The apical and basal rotations changed significantly, from 3.5°± 0.7° to 9.2°± 2.1°, and -2.1°± 0.7° to -3.8°± 1.0°, respectively. Consequently, the LV twist increased significantly, from 5.6°± 1.0° to 13.0°± 1.9°.

CONCLUSIONS

Radial and circumferential strains and LV twist increased significantly in the early postoperative period in functional MR patients after RMA and concomitant procedures.

Surgical treatment of functional mitral regurgitation

Incidence of functional mitral regurgitation (FMR) is increasing due to aging and better survival after acute myocardial infarction, the most frequent cause of FMR. At the basis of FMR there is a displacement of one of both papillary muscle(s) and/or annular enlargement, which can be primitive or, more often, secondary. There is general agreement that its natural history is unfavorable, as witnessed by a considerable body of evidences. However, even if there is no clear evidence that surgical treatment of FMR changes consistently the outcome of patients with this disease, at least in terms of survival, there are some studies which show that function improves, as well as the global quality of life. The guidelines reflect this uncertainty, providing no clear indications, even in the gradation of severity of the FMR. Surgical techniques are variable and are mainly addressed to the annulus (restrictive annuloplasty), which is only a part of the anatomic problem related to FMR. Insertion of a prosthesis inside the native valve is appearing more and more a valuable option rather than a bail out procedure. On the other side, techniques addressed to modify the position of the papillary muscles appear to be still under investigation and not yet in the armamentarium of surgical treatment of FMR. Even after many years, rules are not established and results are fluctuating, but how and when to treat FMR is becoming more and more a topic of interest in cardiac surgery.

Successful postoperative activation of an adjustable annuloplasty ring (MiCardia) in recurrent ischemic mitral valve regurgitation

We report the case of a 73-year-old patient with severe ischemic mitral regurgitation (MR). She subsequently underwent combined coronary artery revascularization and mitral valve annuloplasty using the adjustable enCorSQ device (MiCardia Corporation, Irvine, CA). Three months later she experienced recurrent symptomatic severe MR. Accessing the subcutaneous lead, activation and downsizing of the device within 45 seconds resulted in trace MR. The result was unchanged 1 month later.

Another multidisciplinary look at ischemic mitral regurgitation

Ischemic mitral regurgitation (IMR) continues to challenge surgeons and scientists alike. This vexing clinical entity frequently complicates myocardial infarction and carries a poor prognosis both in the setting of coronary disease and idiopathic dilated cardiomyopathy. Ischemic mitral regurgitation encompasses a difficult patient population that is characterized by high operative mortality, poor long term outcomes, and frequent recurrent insufficiency after standard surgical repair. Yet optimal surgical repair and improved clinical outcomes can only be achieved with better knowledge of the pathophysiology of IMR which is still incompletely understood. The causative mechanism of IMR appears to lie in the annular and subvalvular frame of the valve rather than leaflet or chordal structure leading to such labels as "ischemic," "functional," "non-organic," and "cardiomyopathy associated" being applied in the clinical literature. Although ischemic mitral regurgitation is a prevailing clinical entity, it has not been consistently defined in the literature, contributing to considerable confusion and contradictory results of clinical studies. As the mechanisms of pathophysiology have been better elucidated, novel surgical and interventional strategies have been developed recently to provide better treatment for this difficult patient population. In this review, we undertake a multidisciplinary update of the pathophysiology, classification, and surgical and interventional treatment of ischemic mitral regurgitation in today's clinical practice.

Mitral replacement or repair for functional mitral regurgitation in dilated and ischemic cardiomyopathy: is it really the same?

BACKGROUND

This was a study to compare the results of mitral valve (MV) repair and MV replacement for the treatment of functional mitral regurgitation (MR) in advanced dilated and ischemic cardiomyopathy (DCM).

METHODS

One-hundred and thirty-two patients with severe functional MR and systolic dysfunction (mean ejection fraction 0.32 ± 0.078) underwent mitral surgery in the same time frame. The decision to replace rather than repair the MV was taken when 1 or more echocardiographic predictors of repair failure were identified at the preoperative echocardiogram. Eighty-five patients (64.4%) received MV repair and 47 patients (35.6%) received MV replacement. Preoperative characteristics were comparable between the 2 groups. Only ejection fraction was significantly lower in the MV repair group (0.308 ± 0.077 vs 0.336 ± 0.076, p = 0.04).

RESULTS

Hospital mortality was 2.3% for MV repair and 12.5% for MV replacement (p = 0.03). Actuarial survival at 2.5 years was 92 ± 3.2% for MV repair and 73 ± 7.9% for MV replacement (p = 0.02). At a mean follow-up of 2.3 years (median, 1.6 years), in the MV repair group LVEF significantly increased (from 0.308 ± 0.077 to 0.382 ± 0.095, p < 0.0001) and LV dimensions significantly decreased (p = 0.0001). On the other hand, in the MV replacement group LVEF did not significantly change (from 0.336 ± 0.076 to 0.31 ± 0.11, p = 0.56) and the reduction of LV dimensions was not significant. Mitral valve replacement was identified as the only predictor of hospital (odds ratio, 6; 95% confidence interval, 1.1 to 31; p = 0.03) and overall mortality (hazard ratio, 3.1; 95% confidence interval, 1.1 to 8.9; p = 0.02).

CONCLUSIONS

In patients with advanced dilated and ischemic cardiomyopathy and severe functional MR, MV replacement is associated with higher in-hospital and late mortality compared with MV repair. Therefore, mitral repair should be preferred whenever possible in this clinical setting.

The effect of mitral annuloplasty shape in ischemic mitral regurgitation: a finite element simulation

BACKGROUND

Undersized mitral annuloplasty (MA) is the preferred surgical treatment for chronic ischemic mitral regurgitation. However, the preferred shape of undersized MA is unclear.

METHODS

A previously described finite element model of the left ventricle with mitral valve based on magnetic resonance images of a sheep with chronic ischemic mitral regurgitation after posterolateral myocardial infarction was used. Saddle-shape (Edwards Physio II) and asymmetric (IMR ETlogix) MA rings were digitized and meshed. Virtual annuloplasty was performed using virtual sutures to attach the MA ring. Left ventricular diastole and systole were performed before and after virtual MA of each type.

RESULTS

Both types of MA reduced the septolateral dimension of the mitral annulus and abolished mitral regurgitation. The asymmetric MA was associated with lower virtual suture force in the P2 region but higher force in P1 and P3 regions. Although both types of MA reduced fiber stress at the left ventricular base, fiber stress reduction after asymmetric MA was slightly greater. Neither type of MA affected fiber stress at the left ventricular equator or apex. Although both types of MA increased leaflet curvature and reduced leaflet stress, stress reduction with saddle-shape MA was slightly greater. Both MA types reduced stress on the mitral chordae.

CONCLUSIONS

The effects of saddle-shape and asymmetric MA rings are similar. Finite element simulations are a powerful tool that may reduce the need for animal and clinical trials.

Assessment of Mitral Valve Complex by Three-Dimensional Echocardiography: Therapeutic Strategy for Functional Mitral Regurgitation

The mitral valve complex is consisted of annulus, leaflets, chordae tendineae, papillary muscle (PMs) and surrounding left ventricle. Functional mitral regurgitation (MR) results from left ventricular remodeling such as dilatation or distortion, which displaces the PMs and then tethers the mitral leaflets, restricting leaflet coaptation. Undersized annuloplasty, which has been widely accepted as a simple and effective procedure for functional MR, sometimes worsens the tethering of posterior leaflet and induces recurrent MR. In order to overcome such problems, several additional procedures to the simple annuloplasty have been produced. Three dimensional echocardiography plays an essential role to understand the geometry of mitral valve complex and contributes greatly to decision making of the surgical strategy in functional MR and its postoperative assessment.

Percutaneous Techniques for the Treatment of Patients with Functional Mitral Valve Regurgitation

Percutaneous approaches to mitral regurgitation remain largely investigational. In the last decade, novel percutaneous strategies have opened new options in the treatment of valvular heart disease. Several studies are currently underway to determine the benefits of transcatheter mitral valve repair therapy. Transcatheter chordal procedures are being developed, including chordal cutting and chordal implantation. Transcatheter valve implantation in the mitral position might offer a desirable alternative in selected patients and has been accomplished in a compassionate fashion on rare occasions in patients who are not candidates for surgical valve repair or replacement.

Does stringent restrictive annuloplasty for functional mitral regurgitation cause functional mitral stenosis and pulmonary hypertension?

BACKGROUND

It remains controversial whether restrictive mitral annuloplasty (RMA) for functional mitral regurgitation (MR) can induce functional mitral stenosis (MS) that may cause postoperative residual pulmonary hypertension (PH).

METHODS AND RESULTS

One hundred eight patients with left ventricular (LV) dysfunction and severe MR underwent RMA with stringent downsizing of the mitral annulus. Systolic pulmonary artery pressure (PAP) and mitral valve performance variables were determined by Doppler echocardiography prospectively and 1 month after RMA. Fifty-eight patients underwent postoperative hemodynamic measurements. Postoperative echocardiography showed a mean pressure half-time of 92 ± 14 ms, a transmitral mean gradient of 2.9 ± 1.1 mm Hg, and a mitral valve effective orifice area of 2.4 ± 0.4 cm(2), consistent with functional MS. Doppler-derived systolic PAP was 32 ± 8 mm Hg, which correlated weakly with the transmitral mean gradient (ρ=0.23, P=0.02). Postoperative cardiac catheterization also showed significant improvements in LV volume and systolic function, pulmonary capillary wedge pressure, cardiac index, and systolic PAP; the latter was associated with LV end-diastolic pressure [standardized partial regression coefficient (SPRC)=0.51], pulmonary vascular resistance (SPRC=0.47), cardiac index (SPRC=0.37), and transmitral pressure gradient (SPRC=0.20). In a multivariate Cox proportional hazard model, postoperative PH (systolic PAP >40 mm Hg), but not mitral valve performance variables, was strongly associated with adverse cardiac events.

CONCLUSIONS

RMA for functional MR resulted in varying degrees of functional MS. However, our data were more consistent with the residual PH being caused by LV dysfunction and pulmonary vascular disease than by the functional MS. The residual PH, not functional MS, was the major predictor of post-RMA adverse cardiac events.

Cardiac Resynchronization Therapy as a Therapeutic Option in Patients With Moderate-Severe Functional Mitral Regurgitation and High Operative Risk

Background—

Functional mitral regurgitation (MR) is a common finding in heart failure patients with dilated cardiomyopathy and has important prognostic implications. However, the increased operative risk of these patients may result in low referral or high denial rate for mitral valve surgery. Cardiac resynchronization therapy (CRT) has been shown to have a favorable effect on MR. Aims of this study were to (1) evaluate CRT as a therapeutic option in heart failure patients with functional MR and high operative risk and (2) investigate the effect of MR improvement after CRT on prognosis.

Methods and Results—

A total of 98 consecutive patients with moderate-severe functional MR and high operative risk underwent CRT according to current guidelines. Echocardiography was performed at baseline and 6-month follow-up; severity of MR was graded according to a multiparametric approach. Significant improvement of MR was defined as a reduction ≥1 grade. All-cause mortality was assessed during follow-up (median 32 [range 6.0 to 116] months). Thirteen patients (13%) died before 6-months follow-up. In the remaining 85 patients, significant reduction in MR was observed in all evaluated parameters. In particular, 42 patients (49%) improved ≥1 grade of MR and were considered MR improvers. Survival was superior in MR improvers compared to MR nonimprovers (log rank P <0.001). Mitral regurgitation improvement was an independent prognostic factor for survival (hazard ratio 0.35, confidence interval 0.13 to 0.94; P =0.043).

Conclusions—

Cardiac resynchronization therapy is a potential therapeutic option in heart failure patients with moderate-severe functional MR and high risk for surgery. Improvement in MR results in superior survival after CRT.

Surgical Therapy of End-Stage Heart Failure: Understanding Cell-Mediated Mechanisms Interacting with Myocardial Damage

Worldwide, cardiovascular disease results in an estimated 14.3 million deaths per year, giving rise to an increased demand for alternative and advanced treatment. Current approaches include medical management, cardiac transplantation, device therapy, and, most recently, stem cell therapy. Research into cell-based therapies has shown this option to be a promising alternative to the conventional methods. In contrast to early trials, modern approaches now attempt to isolate specific stem cells, as well as increase their numbers by means of amplifying in a culture environment. The method of delivery has also been improved to minimize the risk of micro-infarcts and embolization, which were often observed after the use of coronary catheterization. The latest approach entails direct, surgical, transepicardial injection of the stem cell mixture, as well as the use of tissue-engineered meshes consisting of embedded progenitor cells.

Management-oriented classification of mitral valve regurgitation

Mitral regurgitation (MR) has previously been classified into rheumatic, primary, and secondary MR according to the underlying disease process. Carpentier's/Duran functional classifications are apt in describing the mechanism(s) of MR. Modern management of MR, however, depends primarily on the severity of MR, status of the left ventricular function, and the presence or absence of symptoms, hence the need for a management-oriented classification of MR. In this paper we describe a classification of MR into 4 phases according to LV function: phase I = MR with normal left ventricle, phase II = MR with normal ejection fraction (EF) and indirect signs of LV dysfunction such as pulmonary hypertension and/or recent onset atrial fibrillation, phase III = EF ≥ 30%-< 50% and/or mild to moderate LV dilatation (ESID 40-54 mm), and phase IV = EF < 30% and/or severe LV dilatation (ESDID ≥ 55 mm). Each phase is further subdivided into three stages: stage "A" with an effective regurgitant orifice (ERO) < 20 mm, stage "B" with an ERO = 20-39 mm, and stage "C" with an ERO ≥ 40 mm. Evidence-based indications and outcome of intervention for MR will also be discussed.

Papillary muscle approximation and relocation with a loop technique for mitral complex repair

Undersized mitral annuloplasty alone is not always sufficient to repair functional mitral regurgitation resulting from left ventricular enlargement; the repair requires a three-dimensional approach to the mitral complex. We introduce a surgical procedure that combines papillary muscle approximation to correct lateral shift and papillary muscle relocation using the loop technique to correct the apical shift with accuracy and technical ease.

Surgical treatment of functional mitral regurgitation in dilated cardiomyopathy

Functional mitral regurgitation is a significant complication of end-stage cardiomyopathy. Dysfunction of one or more components of the mitral valve apparatus occurs in 39-74% and affects almost all heart failure patients. Survival is decreased in subjects with more than mild mitral regurgitation irrespective of the aetiology of heart failure. The goal of treating functional mitral regurgitation is to slow or reverse ventricular remodelling, improve symptoms and functional class, decrease the frequency of hospitalization for congestive heart failure, slow progression to advanced heart failure (time to transplant) and improve survival. This article reviews the role of mitral valve surgery in patients with heart failure and dilated cardiomyopathy.

Mitral valve repair for ischemic mitral regurgitation using the Carpentier-McCarthy-Adams IMR ETlogix® ring: medium-term echocardiographic findings

The aims of this study were to review the principles underlying use of the Carpentier-McCarthy-Adams IMR ETlogix® asymmetric annuloplasty ring for the treatment of chronic ischemic mitral regurgitation and to report medium-term clinical outcomes observed at our center. The in-hospital mortality rate was 2.8%. Echocardiography at hospital discharge confirmed the absence of mitral regurgitation in 88.8% of patients. Patients underwent clinical and echocardiographic follow-up (median duration, 23 months; range, 12-44 months). Late follow-up echocardiography demonstrated the recurrence of moderate mitral regurgitation in 5.7% of patients and of moderate-to-severe mitral regurgitation in 2.9%. The rate of survival free from recurrence of ≥grade-2 mitral regurgitation was 95.2% at 15 months and 88.9% at 25 months. Mitral valve repair using the asymmetric Carpentier-McCarthy-Adams IMR ETlogix® ring in patients with chronic ischemic mitral regurgitation enabled regurgitation to be effectively corrected by producing asymmetric changes in the morphology of the mitral ring. Medium-term outcomes, with regard to the degree of mitral valve competence, were excellent.

Is there a role for surgeons in transcatheter mitral valve procedures?

PURPOSE OF REVIEW

The rapid advancement in transcatheter therapies seeks to provide less invasive options compared with conventional surgery in the treatment of acquired valvular heart disease. A number of transcatheter mitral valve devices using a variety of approaches for the treatment of mitral regurgitation are under development or in early clinical application. Although yet to be clearly defined, there is no doubt that transcatheter mitral valve procedures will have a significant role alongside conventional surgery. The question is: will surgeons, who have led the treatment of mitral valve disease for the past 30 years, have a role in these procedures?

RECENT FINDINGS

In order to answer this question, this review discusses key understanding of mitral valve anatomy, function and disorder required to perform transcatheter mitral valve interventions. It assesses the potential role of transcatheter therapies with particular reference to percutaneous edge-to-edge repair using the Mitraclip system (Abbott Vascular Devices, California, USA). The new era in collaboration between surgeons and cardiologists is discussed and the potential role of the surgeon in percutaneous mitral valve procedures is examined.

SUMMARY

Transcatheter mitral valve procedures demand increasing collaboration between cardiologists and surgeons in order to achieve optimal outcomes. Interventional cardiologists will require dedicated training in the specialized field of transcatheter interventions in acquired structural heart diseases. As the delivery of such therapies brings the interface between interventional cardiology and cardiac surgery ever closer, there is the potential for a niche area in cardiac surgery to develop comprising minimally invasive surgical and transcatheter skills.

Restrictive mitral annuloplasty for functional mitral regurgitation: acute hemodynamics and serial echocardiography

BACKGROUND

Long-term effects of restrictive mitral annuloplasty (RMA), especially on hemodynamics and left ventricular (LV) function in patients with functional mitral regurgitation (MR), have not been fully investigated.

METHODS AND RESULTS

From 1999 to 2008, 44 patients with refractory heart failure and functional MR underwent RMA with stringent downsizing of the mitral annulus. Serial echocardiography was performed to evaluate LV function (reverse remodeling), estimated systolic pulmonary artery pressure (PAP) and mitral valve geometry at baseline and at discharge, and annually thereafter. Cardiac catheterization was performed at baseline, and at discharge to evaluate acute hemodynamic change. There were 3 early deaths, and the 5-year survival rate was 78 ± 8%. In 41 survivors the clinical symptoms, stratified according to New York Heart Association class, significantly improved after surgery. Postoperative cardiac catheterization showed significant unloading for left ventricle, as well as improvement in LV systolic function. Serial echocardiography showed that improvements in LV function and systolic PAP were sustained in the majority of patients. Multivariate Cox regression analysis identified preoperative pulmonary hypertension (systolic PAP>60 mm Hg) as the significant predictor for postoperative adverse cardiac events.

CONCLUSIONS

RMA for functional MR resulted in sustained improvement of hemodynamics and LV function over time. Additional studies are needed to define the negative impact of preoperative pulmonary hypertension in patients with this condition.

Ischaemic mitral regurgitation: pathophysiology, outcomes and the conundrum of treatment

Ischaemic mitral regurgitation is a frequent complication of left ventricular global or regional pathological remodelling due to chronic coronary artery disease. It is not a valve disease but represents the valvular consequences of increased tethering forces (papillary muscles displacement leading to a more apical position of the leaflets and their coaptation point) and reduced closing forces (reduced contractility, dyssynchrony of the papillary muscles, intra-left ventricular dyssynchrony). Although mitral regurgitation has an unloading effect and reduces impedance, the volume overload begets further left ventricular dilatation, increases ventricular wall stress leading to worsened performance. Ischaemic mitral regurgitation is characteristically dynamic: its severity may vary with haemodynamic conditions. Both the severity of ischaemic mitral regurgitation and its dynamic component worsen prognosis. There are numerous possible treatment modalities, but the management of the individual patient remains difficult. Medical therapy is mandatory; revascularization procedures are frequently not sufficient to reduce mitral regurgitation; the role of combined surgical therapy by mitral valve repair is not yet defined in the absence of large randomized trial. Some patients are good candidates for cardiac resynchronization therapy that may reduce the amount of regurgitation. New therapeutic targets are under investigation.

Surgical Ventricular Restoration: An Operation to Reverse Remodeling - Clinical Application (Part II)

The first part of the article dealt with the basic science behind the evolution of ventricular restoration procedures and the rationale for the use of novel surgical techniques. The second part describes the preoperative workup of patients in advanced heart failure, the core information required to determine the surgical approach and the essential principles and techniques of ventricular restoration. It then examines the effects of ventricular restorative procedures on pump function and clinical outcomes, the results of the worldwide experience with ventricular restoration and concludes with more recent advances in this field.

Progress in the treatment of severe mitral regurgitation

Organic mitral regurgitation (MR) is prevalent in the general population. Disease progression, involving potentially irreversible left ventricular dysfunction, implies a poor prognosis for patients who do not receive appropriate treatment. Immediate rescue surgery is indicated in those with severe MR in whom subclinical left ventricular dysfunction is suggested by echocardiographic measurements or the presence of symptoms, however minor. Patients whose symptomatology is unclear should be evaluated by exercise testing. Not all forms of severe organic MR are the same: the presence of risk factors in patients with severe asymptomatic MR and preserved ventricular function indicates a suboptimal prognosis over the medium-to-long term and should prompt early mitral repair if there is a low surgical risk and the probability of a successful repair is >90-95%. The patient should be referred to a specialized surgical center if necessary. Appropriate training of surgeons in mitral repair is essential. Ischemic MR carries a worse prognosis and the risk of surgery is higher. Consequently, treatment decisions must be patient-specific and take into account the possibility of repair, the risk of surgery, and the need for concomitant surgical revascularization. New percutaneous approaches to mitral repair are being developed for selected patient groups.

Surgical options of ischemic mitral regurgitation

Mitral regurgitation after a myocardial infarction is common. It can occur acutely or chronically, and its presence portends a poor prognosis. The focus of this article will be on chronic ischemic mitral regurgitation. We will discuss the current concepts of its pathophysiology, the benefits of revascularization, along with the surgical, and percutaneous therapeutic options.

Assessment of changes in mitral valve configuration with multidetector computed tomography: impact of papillary muscle imbrication and ring annuloplasty

BACKGROUND

The optimal surgical procedures in functional mitral regurgitation remain controversial. We applied papillary muscle imbrication (PMI) combined with undersized mitral annuloplasty (UMAP). Multidetector computed tomography (MDCT) provides images of different phases of the cardiac cycle, allowing an assessment of the geometry. In the present study, we evaluated the mitral valve configuration and subvalvular apparatus before and after UMAP and/or PMI using MDCT imaging.

METHODS AND RESULTS

We studied 26 patients with functional mitral regurgitation (3+ to 4+) with an ejection fraction ≥35% who underwent diagnostic MDCT examinations before and early after the operation. Of these, 15 underwent UMAP and PMI (UMAP+PMI group) and 11 underwent UMAP (UMAP group). The annular anteroposterior diameter, tenting height, tenting area, and interpapillary muscle distance at end-systole were quantified. The annular anteroposterior diameter, tenting height, and tenting area were significantly decreased after the operation in both groups. Whereas the average change in annular anteroposterior diameter, tenting area, and interpapillary muscle distance did not differ between the 2 groups, the average change in tenting height was greater in the UMAP+PMI group than in the UMAP group (5.1±1.3 versus 3.8±2.3 mm, P=0.036). There was a significant correlation between the change in interpapillary muscle distance and the change in tenting height in the UMAP+PMI group (r=0.788, P=0.0005).

CONCLUSIONS

Our results examined with MDCT indicated that UMAP combined with PMI improved leaflet tethering compared with UMAP, reflecting differences in the effects of the surgical procedures used, and suggested that concomitant PMI might be beneficial in some cases.

Percutaneous mitral valve repair using the edge-to-edge technique in a high-risk population

Background. Percutaneous mitral valve (MV) repair using the edge-to-edge clip technique might be an alternative for patients with significant mitral regurgitation (MR) and an unacceptably high risk for operative repair or replacement. We report the short-term safety and efficacy of this new technique in a high-risk population.Methods. All consecutive high-risk patients who underwent percutaneous MV repair with the Mitraclip(®) between January and August 2009 were included. All complications related to the procedure were reported. Transthoracic echocardiography for MR grading and right ventricular systolic pressure (RVSP) measurement were performed before, and at three and 30 days after the procedure. Differences in NYHA functional class and quality of life (QoL) index were reported. Results. Nine patients were enrolled (78% male, age 75.9±9.0 years, logistic EuroSCORE 33.8±9.0%). One patient developed inguinal bleeding. In one patient partial clip detachment occurred, a second clip was placed successfully. The MR grade before repair was ≥3 in 100%, one month after repair a reduction in MR grade to ≤2 was present in 78% (p=0.001). RVSP decreased from 43.9±12.1 to 31.6±11.7 mmHg (p=0.009), NYHA functional class improved from median 3 (range 3 to 4) to 2 (range 1 to 4) (p=0.04), and QoL index improved from 62.9±16.3 to 49.9±30.7 (p=0.12). Conclusion. In high-risk patients, transcatheter MV repair seems to be safe and a reduction in MR can be achieved in most patients, resulting in a short-term improvement of functional capacity and QoL. (Neth Heart J 2010;18:437-43.).

Echocardiographically based treatment of chronic ischemic mitral regurgitation

OBJECTIVES

We evaluated results of an echocardiographically based strategy combining mitral annuloplasty with other procedures to treat chronic ischemic mitral regurgitation.

METHODS

From March 2006 to February 2009, 147 patients underwent mitral valve surgery for chronic ischemic mitral regurgitation. Mean effective regurgitant orifice was 36 ± 11 mm(2), and ejection fraction was 35% ± 9%. On the basis of echocardiographic findings, in 10 cases a prosthesis was inserted and mitral annuloplasty was performed in 137 cases, isolated in 83, associated with chordal cutting in 12 cases (in 5 anterior leaflet was augmented with pericardial patch), and with exclusion of anteroseptal (n = 35) or inferior (n = 7) scars in 42.

RESULTS

Thirty-day mortality was 4.8%; 3-year survival was 86% ± 3%. None of the 126 survivors were in New York Heart Association functional class III or IV. Among 117 survivors of mitral valve repair, after 18 ± 6 months mean effective regurgitant orifice reduced from 34.1 ± 10.2 mm(2) to 2.3 ± 0.4 mm(2) (P < .001). Nine patients showed residual effective regurgitant orifice 10 to 19 mm(2). Reverse remodeling was present in 69 patients (59.0%), no remodeling in 40 (34.1%), and continuous remodeling in 8 (6.9%). Ejection fraction changed from 37% ± 10% to 43% ± 10% (P < .001), improving in 47, remaining unchanged in 63, and worsening in 7.

CONCLUSIONS

Echocardiographically based strategy contributed to reduced postoperative mitral regurgitation persistence (effective regurgitant orifice ≥ 10 mm(2) in 7.7% of cases, with no patients showing effective regurgitant orifice ≥ 20 mm(2)). All patients remained in New York Heart Association functional class I or II, but more than mitral annuloplasty was performed in close to 40%.

Persistent and recurrent ischemic mitral regurgitation

BACKGROUND

Ischemic mitral regurgitation (IMR) is a consequence of coronary artery disease and the main underlying mechanism is augmented leaflet tethering due to outward displacement of the papillary muscles. Although mitral annuloplasty combined with coronary revascularization is usually effective in the treatment of IMR, occasionally the regurgitation can persist or recur and this can affect patient prognosis.

METHODS

We searched Medline and Google scholar database for articles published since 1996 to June 2009. Search terms included ischemic mitral regurgitation, recurrent mitral regurgitation, persistent mitral regurgitation and annuloplasty failure.

CONCLUSION

This article reviews current knowledge about IMR, the reasons and mechanisms of persistent and recurrent mitral regurgitation. We review clinic and echocardiographic predictive factors associated with persistence a recurrence of mitral regurgitation after annuloplasty.

First finite element model of the left ventricle with mitral valve: insights into ischemic mitral regurgitation

BACKGROUND

Left ventricular remodeling after posterobasal myocardial infarction can lead to ischemic mitral regurgitation. This occurs as a consequence of leaflet tethering due to posterior papillary muscle displacement.

METHODS

A finite element model of the left ventricle, mitral apparatus, and chordae tendineae was created from magnetic resonance images from a sheep that developed moderate mitral regurgitation after posterobasal myocardial infarction. Each region of the model was characterized by a specific constitutive law that captured the material response when subjected to physiologic pressure loading.

RESULTS

The model simulation produced a gap between the posterior and anterior leaflets, just above the infarcted posterior papillary muscle, which is indicative of mitral regurgitation. When the stiffness of the infarct region was reduced, this caused the wall to distend and the gap area between the leaflets to increase by 33%. Additionally, the stress in the leaflets increased around the chordal connection points near the gap.

CONCLUSIONS

The methodology outlined in this work will allow a finite element model of both the left ventricle and mitral valve to be generated using noninvasive techniques.

Functional mitral stenosis after surgical annuloplasty for ischemic mitral regurgitation: importance of subvalvular tethering in the mechanism and dynamic deterioration during exertion

OBJECTIVE

Diastolic subvalvular mitral leaflet tethering by left ventricular remodeling that restricts leaflet opening in the presence of annular size reduction by surgery for ischemic mitral regurgitation potentially causes functional mitral stenosis in the absence of organic leaflet lesions. Exercise, known to worsen systolic tethering and ischemic mitral regurgitation, might also dynamically exacerbate such mitral stenosis by increasing tethering. This study evaluates the mechanism and response of such mitral stenosis to exercise.

METHODS

We measured the diastolic mitral valve area, annular area, and peak and mean transmitral pressure gradient by echocardiography in 20 healthy individuals and 31 patients who underwent surgical annuloplasty for ischemic mitral regurgitation.

RESULTS

Although the mitral valve area and annular area did not significantly differ in healthy individuals (4.7 +/- 0.6 cm(2) vs 5.2 +/- 0.6 cm(2), not significant), mitral valve area was significantly smaller than the annular area in patients after annuloplasty (1.6 +/- 0.2 cm(2) vs 3.3 +/- 0.5 cm(2), P < .01). The mitral valve area was less than 1.5 cm(2) only after the surgery (P < .01) and was significantly correlated with restricted leaflet opening (r(2) = 0.74, P < .001), left ventricular dilatation (r(2) = 0.17, P < .05), and New York Heart Association functional class (P < .05). Exercise stress echocardiography of 12 patients demonstrated dynamic worsening in functional mitral stenosis (mitral valve area: 2.0 +/- 0.5 cm(2) to 1.4 +/- 0.2 cm(2), P < .01; mean pressure gradient: 1.5 +/- 0.9 mm Hg to 6.0 +/- 2.2 mm Hg, P < .01).

CONCLUSIONS

Persistent subvalvular leaflet tethering in the presence of annular size reduction by surgery in ischemic mitral regurgitation frequently causes functional mitral stenosis at the leaflet tip level, which is related to heart failure symptoms and can be dynamic with significant exercise-induced worsening.