Systolic anterior motion of the mitral valve after mitral valve repair: a method of prevention

Factors predisposing patients to systolic anterior motion of the mitral valve (SAM) with left ventricular outflow tract (LVOT) obstruction after mitral valve repair are the presence of a myxomatous mitral valve with redundant leaflets, a nondilated hyperdynamic left ventricle, and a short distance between the mitral valve coaptation point and the ventricular septum after repair. From December 1999 through March 2000, we used our surgical method in 6 patients with severely myxomatous regurgitant mitral valves who were at risk of developing SAM. Leaflets were markedly redundant in all 6. Left ventricular function was hyperdynamic in 4 patients and normal in 2. Triangular or quadrangular resection of the midportion of the posterior leaflet and posterior band annuloplasty were performed. To prevent SAM and LVOT obstruction, extra, posteriorly directed, mid-posterior-leaflet secondary chordae tendineae, which would otherwise have been resected, were transferred to the underside of the middle of the mid-anterior leaflet with a small piece of associated valve as an anchoring pledget. This kept the redundant anterior leaflet edge, which extended below the coaptation point, away from the LVOT No post-repair SAM or LVOT obstruction was observed on intraoperative or discharge echocardiography. All patients had no or trivial residual mitral regurgitation. We conclude that extra chordae tendineae, when available, can be used in mitral valve repair to tether the redundant anterior leaflet and thus prevent it from flipping into the LVOT. This will theoretically prevent SAM and LVOT obstruction in patients with risk factors for SAM.     

Validation of a decision-making strategy for systolic anterior motion following mitral valve repair

Low cardiac output syndrome and hypotension are dreadful consequences of systolic anterior motion (SAM) after a mitral valve (MV) repair. The management of SAM in the operating room remains controversial. We validate a recently suggested two-step management method and classification of this complication. This was a teaching hospital-based observational study. We validated a novel two-step conservative management method, consisting in intravascular volume expansion and discontinuation of inotropic drugs (step 1), and increasing the afterload by ascending aorta manual compression while administering esmolol e.v. (step 2). We also validate a novel classification of SAM: easy-to-revert (responding to step 1), difficult-to-revert (responding to step 2), or persistent. Fifty patients had an easy-to-revert while 26 had a difficult-to-revert SAM; 4 patients had a persistent condition (promptly diagnosed through our decisional algorithm) and underwent an immediate second pump run to repeat the mitral repair surgery. We confirmed that SAM after a repair of a degenerative MV is common and validated a simple two-step conservative management method that allows to clearly identify those few patients who require immediate surgical revision.     

Prevention of systolic anterior motion after mitral valve repair with an anterior leaflet valvuloplasty

BACKGROUND AND AIM OF THE STUDY: Mitral valve repair (MVR) is the preferred method of treatment of the complex floppy mitral valve. Immediate repair failure, due to systolic anterior motion (SAM), is related to excessive anterior mitral valve leaflet (AMVL) tissue and/or anterior displacement of the leaflet coaptation point by the posterior mitral valve leaflet (PMVL) with resultant left ventricular outflow tract (LVOT) obstruction. Herein are reported the authors' experience of the AMVL valvuloplasty, a simple alternative to the sliding technique, to prevent post-MVR SAM. METHODS: Between January 1996 and June 2003, elliptical excisions of the base of the AMVL and annuloplasty rings (nine Physio, 38 Seguin) were performed in 47 patients (mean age 66 years; range: 29-86 years). The surgical procedure included posterior mitral valve leaflet (PMVL) resection in 37 patients (80%), AMVL resection in 28 (61%), and transposition flaps in nine (19%). Four patients (8%) had a tricuspid valve repair, six (13%) had an aortic valve replacement, and nine (19%) had coronary bypass grafting. Intraoperative transesophageal echocardiography before and after MVR was performed to assess mitral valve anatomy, the presence and severity of mitral regurgitation (MR), and SAM. RESULTS: There was no postoperative SAM. The severity of MR was reduced to trace or mild in all 47 patients. The mean AMVL length was 3.0 cm before and 2.2 cm after MVR, a tissue reduction of 27%. In those patients with a PMVL resection, the mean length was decreased from 1.95 cm to 1.5 cm, a tissue reduction of 23%. The mean annulus diameter decreased from 3.9 cm to 3.0 cm. The mean AMVL:PMVL ratio decreased from 1.6 to 1.4. The proportional size reduction of the AMVL compared to the PMVL was 17%. The mean coaptation point to annulus distance (CPAD) decreased from 1.1 cm to 0.9 cm. There was no 30-day in-hospital mortality. CONCLUSION: The AMVL valvuloplasty eliminated postoperative SAM. There was both reduction of the AMVL surface area, limiting the excursion of the AMVL into the LVOT, and reduction of CPAD. This technique does not compromise the geometry of the mitral valve apparatus.     

Delayed systolic anterior motion after mitral valve repair

A rare case of systolic anterior motion (SAM) after mitral valve repair is described. A temporary postoperative left ventricular (LV) dysfunction protected against this complication during the early postoperative period. Only on day 9 postoperatively did the left ventricle recover and SAM develop, with significant obstruction of the LV outflow tract. Subsequently, mitral valve replacement was required. This case demonstrates the importance of the LV geometrical relationships that predispose to this complication.     

Echocardiographic predictors of left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve after mitral valve reconstruction for myxomatous valve disease

OBJECTIVE

To determine predictors of systolic anterior motion and left ventricular outflow tract obstruction (SAM/LVOTO) after mitral valve repair (MVRep) in patients with myxomatous mitral valve disease.

BACKGROUND

Mechanisms for the development of SAM/LVOTO after MVRep have been described; however, predictors of this complication have not been explored. We hypothesize that pre-MVRep transesophageal echocardiography (TEE) can predict postrepair SAM/LVOTO.

METHODS

Using TEE, the lengths of the coapted anterior (AL) and posterior (PL) leaflets and the distance from the coaptation point to the septum (C-Sept) were measured before and after MVRep in 33 patients, including 11 who developed SAM/LVOTO (Group 1) and 22 who did not (Group 2).

RESULTS

Group 1 patients had smaller AL/PL ratios (0.99 vs. 1.95, p < 0.0001) and C-Sept distances (2.53 vs. 3.01 cm, p = 0.012) prior to MVRep than those in Group 2. Resolution of SAM/LVOTO was associated with increases in AL/PL ratio and C-Sept distance. This reflects a more anterior position of the coaptation point in those who developed SAM/LVOTO.

CONCLUSIONS

These data suggest that TEE analysis of the mitral apparatus can identify patients likely to develop SAM/LVOTO after MVRep for myxomatous valve disease. The findings are consistent with the concept that SAM of mitral leaflets is due to anterior malposition of slack mitral leaflet portions into the LVOT. The position of the coaptation point of the mitral leaflets is dynamic and a potential target and end point for surgical designs to prevent SAM/LVOTO post MVRep.     

Systolic anterior motion (SAM): a rare cause of late failure in mitral valve repair

Systolic anterior motion (SAM) of the mitral valve is a rare complication of mitral valve repair. The treatment of the large majority of cases is purely medical. Nevertheless, an early degradation may require reoperation (revision of the repair or valve replacement). The authors report two cases of post-repair SAM with a poor outcome with medical therapy which required reoperation after several years. In both cases, an excess of bivalvular tissue with respect to the size of the mitral orifice was observed. A second repair was possible (sliding valvuloplasty associated with an oval resection of the anterior leaflet) with satisfactory long-term results. The identification of the risk factors and careful analysis of the lesions in cases of SAM after mitral valve repair may lead to a repeat repair and the avoidance of mitral valve replacement.     

Echocardiographic correlates of left ventricular outflow obstruction and systolic anterior motion following mitral valve repair

BACKGROUND AND AIM OF THE STUDY: Systolic anterior motion (SAM) of the mitral valve resulting in left ventricular outflow obstruction is a well-recognized complication of repair of the degenerative myxomatous mitral valve. A precise mechanism is unknown. A current approach consists of sliding annuloplasty of the posterior leaflet. It was postulated that excess tissue of the anterior mitral leaflet (AML) was as equally (or more) important as the excess posterior mitral leaflet (PML) tissue in the development of SAM subsequent to valve repair. METHODS: Thirty-two patients without post-repair SAM (No-SAM group) were compared with eight patients with SAM (SAM group). The AML and PML heights and the mitral annulus diameter were measured by TEE using mid-esophageal four-chamber and long-axis planes. RESULTS: Pre-repair TEE showed the AML height to be greater in the SAM group (p = 0.04), and that of the posterior leaflet tended to be greater (p = 0.08), whilst the annular dimensions were similar in both groups. In the post-repair status, the AML height was markedly greater (p = 0.005) and the annulus markedly smaller (p = 0.001) in the SAM group. Post-repair assessment showed the relative difference between AML height and annular dimension (AML - Ann) as well as the difference between combined leaflet heights and annular dimension (AML + PML - Ann) to be strikingly greater in the SAM group as compared with the No-SAM group (p = 0.001). CONCLUSION: A disparity between dimension of the annulus following mitral valve repair and combined heights of the two leaflets explains post-repair SAM. The AML height is a more important factor in the development of SAM. Thus, surgical techniques to reduce AML heights should be considered in patients with disproportionately large anterior leaflets in order to prevent SAM. Selection of size of the annuloplasty ring should take into consideration the height of the AML.     

Systolic anterior motion of the mitral valve after Carpentier ring valvuloplasty for mitral valve prolapse

Between July 1983 and March 1985, 45 patients with severe mitral regurgitation underwent mitral valvuloplasty with insertion of a semirigid Carpentier ring. No patient had echocardiographic evidence of systolic anterior motion (SAM) preoperatively, whereas 5 patients had this echocardiographic finding postoperatively. All 5 had mitral valve prolapse as their underlying disease process and SAM developed at varying intervals after valvuloplasty. The development of SAM is related to insertion of the semirigid ring, persistence of a redundant anterior mitral leaflet, narrowing of the left ventricular (LV) outflow tract and the Venturi effect. LV and aortic pressure measurements with simultaneous Doppler echocardiography have confirmed the presence of a significant LV outflow tract gradient in these patients. Although all 5 patients are functionally improved after mitral valvuloplasty, the long-term implications of SAM after valvuloplasty are unknown.     

Left ventricular outflow tract obstruction after mitral valve repair treated with alcohol septal ablation

Left ventricular outflow tract (LVOT) obstruction due to systolic anterior motion of the mitral valve (SAM) occurs in 4–5% of patients after mitral valve repair. If conservative treatment is unsuccessful, reoperation is indicated. Treatment options include repeated mitral valve repair or valve replacement and septal myectomy if hypertrophy is present. We report a case of a patient with pre‐operatively undiagnosed hypertrophic cardiomyopathy who suffered from progressive dyspnea post‐operation due to severe LVOT obstruction with SAM. This case was successfully treated with catheter‐based alcohol septal ablation. © 2013 Wiley Periodicals, Inc.     

Systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy. A cross-sectional echocardiographic study

Different cross-sectional echocardiographic patterns of systolicanterior motion of the mitral valve (SAM) have been observedin patients with hypertrophic cardiomyopathy. Chordae tendineaeand/or the free edge of the mitral valve were seen to be involvedin some: SAM(c). The body of the mitral valve encroached uponthe left ventricular outflow tract in this movement in a secondgroup: SAM(v). Other patients did not show SAM. A study of 27patients was performed to investigate the relationship of thesepatterns of SAM to the subaortic gradient as well as the prevalenceand degree of mitral re gurgitation. The absence of SAM correlatedwith no obstruction and 29% prevalence of mitral re gurgitation.In SAM(c), the mean gradient was 10±10 mmHg. (0–35mmHg), and mitral regurgitation involved 36% of the patients.In SAM(v) the mean gradient found was 81 ±37 mmHg (20–150),and 67% had mitral regurgitation. In situations where mitralregurgitation was most prevalent its degree was greatest. Inconclusion: (1) chordal or leaflet participation in SAM is relevantto the presence and degree of obstruction: (2) leaflet involvementusually implies severe obstruction: (3) distortion of the mitralvalve apparatus may contribute to the genesis of mitral.     

Severe left ventricular outflow tract obstruction as a complication of mitral valve repair: case report

Systolic anterior motion (SAM) is a postoperative complication of mitral valve repair, with an incidence of 5 to 10%. Early recognition of the signs and symptoms of SAM is essential for the management of these patients. This article focuses on the pathophysiology and dynamics of SAM and the treatment strategies described in the literature. The authors present a case study and echocardiographic images illustrating the clinical relevance of the mechanism involved, in order to clarify whether surgical reintervention is necessary.     

The significance of systolic anterior motion (SAM) on the mitral valve echo pattern in hypertrophic cardiomyopathy

The systolic anterior motion (SAM) of valve structures in the mitral echogram in hypertrophic cardiomyopathy (HCM) has previously been considered to be anterior motion and re-opening of mitral valve leaflets, causing left ventricular outflow tract (LVOT) obstruction and mitral regurgitation. Fifteen patients with HCM underwent cardiac catheterisation and were also examined by M-scan and mechanical real-time B-scan techniques. In all patients SAM was seen during M-scan echocardiography. The mitral valve leaflets were visualised during the entire cardiac cycle during real-time B-scanning without showing any re-opening in systole. Thickened papillary muscles have been observed in 12 patients and prominent chordae tendineae moving in the opposite direction to the anterior mitral valve leaflet in 10 patients. Four patients with SAM did not show mitral regurgitation during left ventricular angiography. In two patients without fixed haemodynamic obstruction, a complete SAM touching the interventricular septum was observed with prolonged apposition in one case. These findings suggest that SAM is due to the motion of chordae tendineae and/or papillary muscles traversing the single dimensional ultrasonic beam in systole, thus producing single linear or multiple spotty echoes within SAM. The mechanism of the upward motion of the subvalvular mitral valve apparatus in systole appears to be due to forceful contraction of the apical left ventricular posterior wall. The observation of SAM in patients without HCM also indicates that its presence during single dimensional echocardiography is neither diagnostic nor specific for HCM, LVOT obstruction or mitral regurgitation, and contradicts the assumption that the anterior mitral valve leaflet plays a significant role in the mechanism of LVOT obstruction. The salient feature of all conditions associated with abnormal mitral subvalvular motion is hyperkinetic contraction of the apical left ventricular posterior wall. Hyperkinetic left ventricular ejection appears to be the main factor in the complex development of an LVOT gradient in hypertrophic cardiomyopathy.     

二尖瓣前叶脱垂手术修复的疗效分析

目的 探讨治疗二尖瓣前叶脱垂的外科修复方法及治疗效果.方法 1998年11月至2007年10月对210例二尖瓣前叶脱垂患者行二尖瓣修复术,并在术前、术中、术后利用超声心动图对心脏结构及功能进行评价.结果 采用缘对缘技术修复二尖瓣前叶脱垂134例(63.8%).出院时心脏功能(纽约心脏病协会分级)Ⅰ级168例,Ⅱ级40例.随访1～150(25.7±29.0)个月,围术期死亡2例(0.95%).超声心动图检查显示,术前左心房舒张末径为(47.5±12.7)mm,术后1年减小为(37.7±9.2)mm(P＜0.05);术前左心室舒张末径为(67.7±10.3)mm,术后1年减小为(51.7±7.9)mm(P＜0.05);术前左心室射血分数为(52.2±6.4)%,术后1年提高为(62.2±3.2)%(P＜0.05);术前二尖瓣反流面积为(10.4±4.1)cm~2,术后1年减少为(4.1±1.7)cm~2(P＜0.01).结论 二尖瓣修复术治疗二尖瓣前叶脱垂可获得良好的手术效果.缘对缘技术修复二尖瓣前叶脱垂安全、有效.     

Genesis of systolic anterior motion (SAM) of the mitral valve in patients with aortic regurgitation

This study was performed to evaluate the incidence and genesis of systolic anterior motion (SAM) of the mitral valve apparatus in patients with aortic regurgitation (AR). The study population consisted of 44 patients with non-rheumatic AR, without significant aortic stenosis or mitral regurgitation. The presence and location of SAM in the short-axis view were determined by M-mode echocardiography guided by two-dimensional echocardiography. The extent and direction of the regurgitant jet were decided by pulsed or two-dimensional Doppler echocardiography. SAM was observed in 21 (48%) of the 44 patients, and it was more frequently observed in patients with an etiology of aortic valve prolapse or annuloaortic ectasia than in those of other etiology (10/14 vs 10/30; p less than 0.05). Twenty-eight patients whose regurgitant jet was directed posteriorly and impinged on the mitral valve apparatus had a significantly higher incidence of SAM than did the other 16 patients (18/28 vs 3/16; p less than 0.01). In eight of 10 patients in whom the direction of the regurgitant jet could be precisely observed by two-dimensional Doppler echocardiography. SAM was observed at the place where a regurgitant jet was directed along the anterior mitral valve in the short-axis view. M-mode measurements (LVDd, LVDs, %FS, LVDd-LVDs) of the patients with SAM had greater values than those of patients without SAM.(ABSTRACT TRUNCATED AT 250 WORDS)     

Status of mitral valve surgery

PURPOSE OF REVIEW: To review the evolution of mitral valve repair and outline currently favored repair techniques. RECENT FINDINGS: Chordal replacement with polytetrafluoroethylene sutures is an accepted and reproducible technique for repair of the anterior leaflet. Most posterior leaflet problems can be addressed with either a quadrangular resection or a sliding repair. SUMMARY: Mitral valve surgery has gradually evolved over the period of the last 50 years. Initially, most surgeons replaced the mitral valve in patients with regurgitant disease. It is now known, however, that long-term outcome for patients undergoing repair is superior to that for patients undergoing replacement. Mitral valve repair avoids the complications associated with the artificial valve and anticoagulation. The ability to reproducibly repair the mitral valve requires a detailed knowledge of the disease process and the reparative techniques. This article describes the current approach to mitral valve surgery and the important concepts necessary to achieve a durable repair.     

Simultaneous occurrence of mitral valve prolapse and systolic anterior motion in hypertrophic cardiomyopathy

This report describes the simultaneous occurrence of mitral valve prolapse (MVP) and systolic anterior motion (SAM) in hypertrophic cardiomyopathy (HC). In 25 patients (aged 7 to 62 years, mean 29), 15 (60%) of whom were male, distal portions of the anterior or posterior mitral leaflets approached or made midsystolic contact with the ventricular septum, whereas the proximal portion of the mitral leaflets showed marked cephalad excursion into the left atrium, 5 to 15 mm beyond the mitral annular plane. Three mitral valves that were available for gross visual inspection were not morphologically typical of patients with primary MVP. Clinical features and natural history (1 to 14 years [mean 6] of follow-up), cardiac dimensions, and distribution of left ventricular hypertrophy defined in the study patients did not appear to differ distinctly from those in the overall referral population of patients with HC evaluated at our institution. Hence, patients with HC may show a striking pattern of mitral valvular motion involving SAM into the left ventricular outflow tract, as well as MVP; this prolapse motion is probably due to anatomic disproportion between the mitral valve and the small left ventricular cavity rather than to the coexistence of 2 separate disease entities. Such patients further define the great diversity evident within the broad clinical spectrum of HC.     

Surgical timing for mitral valve regurgitation

Advances in diagnostic and surgical techniques in the management of mitral regurgitation have resulted in improved survival rates and clinical outcomes. Echocardiography is a valuable noninvasive diagnostic tool in the determination of the timing of surgical correction of mitral regurgitation. Improved surgical techniques, the growing role of mitral valve repair, low operative mortality rates, and improved long-term survival rates are important considerations for earlier surgical intervention in symptomatic patients and in asymptomatic patients with echocardiographic criteria of left ventricular dilatation. Intraoperative transesophageal echocardiography is very useful in mitral valve repair and valve replacement with preservation of chordal structures.     

Complicated mitral valve repairs

The standard of care for mitral regurgitation secondary to degenerative valvular disease is mitral valve repair whenever possible. Mitral valve repair is associated with better left ventricular function preservation, fewer complications, and improved survival as compared with mitral valve replacement. Most of the mitral valve pathology involves the posterior leaflet or annulus and usually can be repaired by using standard valve repair techniques. Difficulties may arise when trying to repair the somewhat uncommon anterior leaflet prolapse or calcified mitral annulus. This article reviews these more complex mitral valve repair techniques and their outcomes.     

Transient mitral regurgitation due to mitral valve prolapse accompanied by systolic anterior motion of the mitral valve

A grade 4/6 systolic murmur, systolic anterior motion of the mitral valve (SAM), and severe mitral regurgitation (MR) documented by two-dimensional Doppler echocardiography developed suddenly on the structurally normal heart of a patient with idiopathic portal hypertension. The patient did not have signs of congestive heart failure and the aforementioned phenomenon disappeared completely when the patient was in hepatic failure. This could be explained by a change in circulating blood volume either by gastrointestinal hemorrhage or hepatic failure.     

Mitral valve and its ring in hypertrophic cardiomyopathy--a mechanism creating surplus mitral leaflet involved in systolic anterior motion

A large surplus portion of the mitral leaflets appears to be involved in the systolic anterior motion (SAM) of the mitral valve in hypertrophic cardiomyopathy (HCM). To understand the exact features and the mechanism of the surplus leaflet, we studies the mitral valve and its ring quantitatively with two-dimensional echocardiography in 17 patients with HCM (5 with large SAM, 6 with small SAM and 6 without SAM) and 10 normal subjects. In the large SAM group, the surplus length of the anterior mitral leaflet (AML) increased but that of the posterior mitral leaflet (PML) did not increase when compared to the other 3 groups. In the large SAM group, the length of AML was greater than in the normal group and the length of PML was greater than in the other 3 groups. The mid-systolic anteroposterior diameter of the mitral ring did not differ among the 4 groups. The mid-systolic position of the coaptation was more anterior in the large SAM group than in the other 3 groups. In conclusion, the surplus size of AML is actually increased in the patients with HCM and large SAM, which is caused by the elongation of both AML and PML with anteriorly displaced coaptation and with no dilation of the mitral ring.