Mechanism of higher incidence of ischemic mitral regurgitation in patients with inferior myocardial infarction: quantitative analysis of left ventricular and mitral valve geometry in 103 patients with prior myocardial infarction

OBJECTIVE: The mechanism of higher incidence of ischemic mitral regurgitation in patients with inferior compared with anterior myocardial infarction despite less global left ventricular remodeling and dysfunction is controversial. We hypothesized that inferior myocardial infarction causes left ventricular remodeling, which displaces posterior papillary muscle away from its normal position, leading to ischemic mitral regurgitation. METHODS: In 103 patients with prior myocardial infarction (61 anterior and 42 inferior) and 20 normal control subjects, we evaluated the grade of ischemic mitral regurgitation on the basis of the percentage of Doppler jet area, left ventricular end-diastolic and end-systolic volumes, midsystolic mitral annular area, and midsystolic leaflet-tethering distance between papillary muscle tips and the contralateral anterior mitral annulus, which were determined by means of quantitative echocardiography. RESULTS: Global left ventricular dilatation and dysfunction were significantly less pronounced in patients with inferior myocardial infarction (left ventricular end-systolic volume: 52 +/- 18 vs 60 +/- 24 mL, inferior vs anterior infarction, P<.05; left ventricular ejection fraction: 51% +/- 9% vs 42% +/- 7%, P <.0001). However, the percentage of mitral regurgitation jet area and the incidence of significant regurgitation (percentage of jet area of 10% or greater) was greater in inferior infarction (percentage of jet area: 10.1% +/- 7.5% vs 4.4% +/- 7.0%, P =.0002; incidence: 16/42 (38%) vs 6/61 (10%), P <.0001). The mitral annulus (area = 8.2 +/- 1.2 cm2 in control subjects) was similarly dilated in both inferior and anterior myocardial infarction (9.7 +/- 1.7 vs. 9.5 +/- 2.3 cm2, no significant difference), and the anterior papillary muscle-tethering distance (33.8 +/- 2.6 mm in control subjects) was also similarly and mildly increased in both groups (35.2 +/- 2.4 vs 35.2 +/- 2.8 mm, no significant difference). However, the posterior papillary muscle-tethering distance (33.3 +/- 2.3 mm in control subjects) was significantly greater in inferior compared with anterior myocardial infarction (38.3 +/- 4.1 vs 34.7 +/- 2.9 mm, P =.0001). Multiple stepwise regression analysis identified the increase in posterior papillary muscle-tethering distance divided by body surface area as an independent contributing factor to the percentage of mitral regurgitation jet area (r2 = 0.70, P <.0001). CONCLUSIONS: It is suggested that the higher incidence and greater severity of ischemic mitral regurgitation in patients with inferior compared with anterior myocardial infarction can be related to more severe geometric changes in the mitral valve apparatus with greater displacement of posterior papillary muscle caused by localized inferior basal left ventricular remodeling, which results in therapeutic implications for potential benefit of procedures, such as infarct plication and leaflet or chordal elongation, to reduce leaflet tethering.     

Ischemia in three left ventricular regions: Insights into the pathogenesis of acute ischemic mitral regurgitation

BACKGROUND: Acute posterolateral left ventricular ischemia in sheep results in ischemic mitral regurgitation, but the effects of ischemia in other left ventricular regions on ischemic mitral regurgitation is unknown. METHODS: Six adult sheep had radiopaque markers placed on the left ventricle, mitral annulus, and anterior and posterior mitral leaflets at the valve center and near the anterior and posterior commissures. After 6 to 8 days, animals were studied with biplane videofluoroscopy and transesophageal echocardiography before and during sequential balloon occlusion of the left anterior descending, distal left circumflex, and proximal left circumflex coronary arteries. Time of valve closure was defined as the time when the distance between leaflet edge markers reached its minimum plateau, and systolic leaflet edge separation distance was calculated on the basis of left ventricular ejection. RESULTS: Only proximal left circumflex coronary artery occlusion resulted in ischemic mitral regurgitation, which was central and holosystolic. Delayed valve closure (anterior commissure, 58 +/- 29 vs 92 +/- 24 ms; valve center, 52 +/- 26 vs 92 +/- 23 ms; posterior commissure, 60 +/- 30 vs 94 +/- 14 ms; all P <.05) and increased leaflet edge separation distance during ejection (mean increase, 2.2 +/- 1.5 mm, 2.1 +/- 1.9 mm, and 2.1 +/- 1.5 mm at the anterior commissure, valve center, and posterior commissure, respectively; P <.05 for all) was seen during proximal left circumflex coronary artery occlusion but not during left anterior descending or distal left circumflex coronary artery occlusion. Ischemic mitral regurgitation was associated with a 19% +/- 10% increase in mitral annular area, and displacement of both papillary muscle tips away from the septal annulus at end systole. CONCLUSIONS: Acute ischemic mitral regurgitation in sheep occurred only after proximal left circumflex coronary artery occlusion along with delayed valve closure in early systole and increased leaflet edge separation throughout ejection in all 3 leaflet coaptation sites. The degree of left ventricular systolic dysfunction induced did not correlate with ischemic mitral regurgitation, but both altered valvular and subvalvular 3-dimensional geometry were necessary to produce ischemic mitral regurgitation during acute left ventricular ischemia.     

Papillary muscle sling and overlapping cardiac volume reduction with aortic valve replacement for valvular cardiomyopathy

A 63-year-old male was admitted to our hospital because of severe aortic regurgitation. The left ventricle was extremely dilated and mild functional mitral regurgitation was detected because of outward displacement of papillary muscles. We used a papillary muscle sling with aortic valve replacement to correct the widened distance between the papillary muscles. A papillary muscle sling when used for reducing tethering at the mitral valve also reduces the posterior left ventricular volume. As well, a transmural longitudinal incision along the left anterior descending artery in the left ventricular free wall was sutured by an overlapping method to reduce the anterior left ventricular volume. The combination of papillary muscle sling and the overlapping method does not need any resection of the cardiac muscle and so would be beneficial for end-stage valvular cardiomyopathy.     

The effects of mitral annuloplasty rings on mitral valve complex 3-D geometry during acute left ventricular ischemia.

OBJECTIVE: Annuloplasty rings are used to treat ischemic mitral regurgitation (IMR), but their exact effects on 3-D geometry of the overall mitral valve complex during acute left ventricular (LV) ischemia remain unknown. METHODS: Radiopaque markers were sutured to the mitral leaflet edges, annulus, papillary muscle tips, and ventricle in three groups of sheep. One group served as control (n = 5), and the others underwent Duran (n = 6) or Physio (n = 5) ring annuloplasty. One week later, 3-D marker coordinates at end-systole were obtained before and during balloon occlusion of the circumflex artery. RESULTS: In all control animals, acute LV ischemia was associated with: (i) septal-lateral separation of the leaflet edges, which was predicted by lateral displacement of the lateral annulus during septal-lateral mitral annular dilatation; (ii) apical restriction of the posterior leaflet edge, which was predicted by displacement of the lateral annulus away from the non-ischemic anterior papillary muscle; (iii) displacement of the posterior papillary muscle, which was not predictive of either septal-lateral leaflet separation or leaflet restriction; and (iv) mitral regurgitation. In the Duran group during ischemia, the posterior leaflet edge shifted posteriorly due to posterior movement of the lateral annulus, but no IMR occurred. In the Physio group during ischemia, neither the posterior leaflet edge nor the lateral annulus changed positions, and there was no IMR. In both the Duran and Physio groups, displacement of the posterior papillary muscle did not lead to IMR. CONCLUSIONS: Either annuloplasty ring prevented the perturbations of mitral leaflet and annular--but not papillary muscle tip--3-D geometry during acute LV ischemia. By fixing the septal-lateral annular dimension and preventing lateral displacement of the lateral annulus, annuloplasty rings prevented systolic septal-lateral leaflet separation and posterior leaflet restriction, and no acute IMR occurred. The flexible ring allowed posterior displacement of the posterior leaflet edge and the lateral annulus, which was not observed with a semi-rigid ring.     

Restoring papillary muscle dimensions during restoration in dilated hearts

Left ventricular papillary muscle geometry is distorted in dilated non-ischemic hearts, and following anterior infarction caused by a wrap around left anterior descending artery occlusion. Loss of the apex creates a spherical left ventricular (LV) chamber, and subsequent dilation causes secondary mitral insufficiency by stretching the annulus, altering tethering of the chords and widening the dimension between the bases of papillary muscles to impair leaflet coaptation. This report will describe an intraventricular way to narrow the widened inter papillary muscle distance toward normal.     

Annuloplasty ring selection for chronic ischemic mitral regurgitation: lessons from the ovine model

BACKGROUND: Chronic ischemic mitral regurgitation (CIMR) is poorly understood and repair operations are often unsatisfactory. This study elucidates the mechanism of CIMR in an ovine model. METHODS: Sonomicrometry array localization measured the three-dimensional geometry of the mitral annulus and subvalvular apparatus in five sheep before and 8 weeks after a posterior infarction of the left ventricle that produced progressive severe CIMR. RESULTS: End systolic annular area increased from 647 +/- 44 mm(2) to 1,094 +/- 173 mm(2) (p = 0.01). Annular dilatation occurred equally along the anterior (47.0 +/- 5.6 mm to 60.2 +/- 4.9 mm, p = 0.001) and posterior (53.8 +/- 3.1 mm to 68.5 +/- 8.4 mm, p = 0.005) portions of the annulus. The tip of the anterior papillary muscle moved away from both the anterior and posterior commissures by 5.2 +/- 3.2 mm (p = 0.021) and 7.3 +/- 2.2 mm (p = 0.002), respectively. The distance from the tip of the posterior papillary muscle to the anterior commissure increased by 11.0 +/- 5.7 mm (p = 0.032) while the distance from the tip of the posterior papillary muscle to the posterior commissure remained constant. CONCLUSIONS: Progressive dilatation of both the anterior and posterior mitral annuli, increased annular area, and asymmetric ventricular dilatation combine to cause CIMR by distortion of mitral valve geometry and tethering of leaflet coaptation. Therefore complete ring annuloplasty may be superior to partial annuloplasty in the treatment of CIMR.     

Surgical treatment of left ventricular aneurysm associated with mitral regurgitation

The purpose of this study is to analyze the early and late results of left ventricular aneurysmectomy in patients with mitral regurgitation secondary to myocardial infarction. Twenty patients who had left ventricular aneurysm combined with mitral regurgitation underwent the isolated or combined aneurysmectomy during the last 10 years. There were 18 male cases and 2 female cases, and their age ranged from 31 to 64 (mean age 52.6 years). In 19 cases, the left ventricular aneurysm were caused secondary to antero-septal infarction due to the occlusion of the left anterior descending coronary artery. In one case, the coronary spasm of circumflex artery provoked the posterolateral myocardial infarction and the tendon rupture of posterior papillary muscle. The isolated left ventricular aneurysmectomy were performed in 6 cases and the combined operations were coronary artery bypass grafting in 11 cases, mitral annuloplasty in 1 case, mitral annuloplasty and bypass grafting in 1 case, and mitral replacement in 1 case. There were no operative death cases. The preoperative mean functional class (NYHA classification) was 2.9 and the postoperative class was 1.4. The preoperative mitral regurgitation of grade 1 in Sellers' classification was observed in 11 cases. Grade 2 regurgitation was observed in 6 cases, grade 3 in 2 and grade 4 in 1. After surgery, mitral regurgitation more than grade 2 was recognized in 3 cases (group A) and regurgitation less than grade 1 was seen in 17 cases (group B).(ABSTRACT TRUNCATED AT 250 WORDS)     

Annular or subvalvular approach to chronic ischemic mitral regurgitation?

OBJECTIVE: We sought to investigate whether annular or subvalvular interventions corrected chronic ischemic mitral regurgitation differently. METHODS: Sheep underwent placement of markers on the left ventricle, mitral annulus, papillary muscles (anterior and posterior), and both leaflet edges. A transannular suture (septal-lateral annular cinching) was anchored to the midseptal mitral annulus and externalized through the midlateral mitral annulus. Another suture (papillary muscle repositioning) from the posterior papillary muscle was passed through the mitral annulus near the posterior commissure and externalized. After 7 days, 3-dimensional marker data were obtained before inducing posterolateral myocardial infarction. After 7 weeks, animals in whom chronic ischemic mitral regurgitation developed (n = 10) were restudied before and after pulling septal-lateral annular cinching or papillary muscle repositioning sutures. End-systolic septal-lateral annular diameter and 3-dimensional displacement of the papillary muscles and leaflet edges were computed. RESULTS: Infarction increased mitral regurgitation (0.6 +/- 0.5 to 2.3 +/- 1.1); mitral annular septal-lateral dilation (4 +/- 1 mm); posterior papillary muscle displacement laterally (4 +/- 2 mm), posteriorly (9 +/- 3 mm), and toward the annulus (2 +/- 1 mm); posterior mitral leaflet apical tethering (3 +/- 1 mm); and interleaflet separation (+3 +/- 1 mm, P < .05 baseline vs chronic ischemic mitral regurgitation). Septal-lateral annular cinching reduced septal-lateral dimension (-9 +/- 3 mm), corrected lateral posterior papillary muscle displacement (4 +/- 1 mm) and septal-lateral interleaflet separation (-4 +/- 2 mm), and decreased mitral regurgitation (0.6 +/- 0.6, P < .05 septal-lateral annular cinching vs chronic ischemic mitral regurgitation) without affecting posterior leaflet restriction. Papillary muscle repositioning reduced septal-lateral diameter (-4 +/- 1 mm), moved the anterior papillary muscle closer to the annulus (2 +/- 1 mm), and relieved posterior leaflet apical restriction (2 +/- 1 mm, P < .05 papillary muscle repositioning vs chronic ischemic mitral regurgitation) but did not change lateral posterior papillary muscle displacement or decrease mitral regurgitation (1.9 +/- 1.2). CONCLUSIONS: Septal-lateral annular cinching moved the lateral annulus and the posterior papillary muscle closer to the septum and reduced mitral regurgitation unlike posterior papillary muscle repositioning, and thus the key mitral subvalvular repair component must correct posterior papillary muscle lateral displacement.     

Changes in mitral annular and left ventricular dimensions and left ventricular pressure-volume relations after off-pump treatment of mitral regurgitation with the Coapsys device.

OBJECTIVE: The objective of this study was to evaluate the changes in mitral annular and left ventricular dimensions and left ventricular pressure-volume relations produced by the Myocor Coapsys device that has been developed to treat functional mitral regurgitation (MR) off-pump. METHODS: The Coapsys device, which consists of anterior and posterior epicardial pads connected by a sub-valvular chord, was implanted in seven dogs with functional MR resulting from pacing induced cardiomyopathy. The Coapsys device was then sized by drawing the posterior leaflet and annulus toward the anterior leaflet. During sizing, MR grade was assessed using color flow Doppler echocardiography. Final device size was selected when MR was eliminated or minimized. Following implantation, heart failure was maintained by continued pacing for a period of 8 weeks. Mitral annular and left ventricular dimensions and left ventricular pressure-volume relations were evaluated by two-dimensional echocardiography and a conductance catheter, respectively, at pre-sizing, post-sizing, and after 8 weeks. RESULTS: All implants were performed on beating hearts without cardiopulmonary bypass. Mean MR grade was reduced from 2.9+/-0.7 at pre-sizing to 0.7+/-0.8 at post-sizing (P<0.001), and was maintained at 0.8+/-0.8 after 8 weeks (P<0.01). The septal-lateral dimensions were significantly reduced at both mitral annular level [2.4+/-0.2 cm at pre-sizing, 1.5+/-0.3 cm at post-sizing (P<0.001) and 1.8+/-0.3 cm after 8 weeks (P<0.05)] and mid-papillary level [4.1+/-0.4 cm at pre-sizing, 2.4+/-0.2 cm at post-sizing (P<0.001) and 3.3+/-0.4 cm after 8 weeks (P<0.001)]. The end-systolic pressure-volume relation shifted leftward at post-sizing with a significantly steeper slope (P=0.03). There was a significant (P=0.03) leftward shift of the end-diastolic pressure-volume relation at post-sizing. After 8 weeks, these changes in pressure-volume relations tended to return to pre-sizing relations. CONCLUSIONS: The Coapsys device significantly reduced MR by treating both the mitral annular dilatation and the papillary muscle displacement. Despite these significant dimensional changes, the Coapsys device did not negatively affect the left ventricular pressure-volume relations.     

Left ventricular function in subacute and chronic mitral regurgitation. Effect on function early postoperatively

Quantitative analysis of biplane ventriculograms, including calculation of the end-systolic pressure/volume ratio, was used to define left ventricular systolic performance in 10 normal subjects, 10 patients with symptomatic subacute (less than 6 months' duration) mitral regurgitation, and 18 patients with symptomatic chronic mitral regurgitation. Left ventricular volume, mass, and systolic function were similar for patients with subacute and with chronic mitral regurgitation, suggesting that some patients with recent-onset nonischemic mitral regurgitation have partial adaptation to chronic valve insufficiency prior to their symptomatic event. Rate of development of left ventricular wall stress in early systole was increased in subacute mitral regurgitation compared with chronic mitral regurgitation and normal subjects. Duration of symptoms did not correlate with degree of ventricular adaptation to mitral regurgitation, and end-systolic indices of left ventricular performance did not predict early postoperative clinical response to valve replacement or repair.     

Ischemic cardiomyopathy treated with overlapping ventriculoplasty

A 58-year-old man was admitted due to congestive heart failure. Left ventriculography showed end-diastolic volume index (EDVI) of 172 ml/m2 and ejection fraction (EF) of 16%. Coronary angiography showed severe double vessel disease (the left anterior descending artery and the right coronary artery). Echocardiography showed dilated heart [left ventricular end-diastolic diameter (LVDd) of 74 mm] and severe mitral regurgitation due to tethering of the leaflets. The patient underwent our original left ventricular volume reduction operation, termed overlapping ventriculoplasty (OLVP) combined with mitral annuloplasty, papillary muscles plication (PMP) and coronary artery bypass grafting (CABG). The postoperative course was excellent. Postoperatively, the EDVI decreased to 96 ml/m2, the LVDd diminished to 67 mm, and the EF improved to 34%. This case implies the role of left ventricular remodeling procedure of OLVP and PMP in the ischemic cardiomyopathy with ischemic mitral regurgitation.     

Partial Left Ventriculectomy in Patients with Dilated Failing Ventricle

BACKGROUND: While partial left ventriculectomy (PLV) improves left ventricular energetic efficiency, concomitant reduction in mitral regurgitation may improve ventricular function. METHODS: Two hundred ninety-five patients undergoing lateral ventricular wall excision between the papillary muscles (lateral PLV) and 101 patients with an additional excision of papillary muscles and mitral valve replacement (extended PLV) were compared with 65 patients undergoing excision of anterior wall or ventricular aneurysm (anterior PLV). RESULTS: All patients had reduced functional capacity, New York Heart Association (NYHA) Class III to IV (3.62+/-0.49). Etiologies were cardiomyopathy (37.3%), coronary artery disease (32.3%), valvular disease (19.7%), Chagas' disease (7.8%), and others (2.8%). Patients undergoing lateral and extended PLV had cardiomyopathy as the primary cause of heart failure, while a majority of anterior PLV patients had ischemic disease. Associated procedures included mitral valvuloplasty or replacement (lateral PLV 67%, extended PLV 100%, anterior PLV 40%) and tricuspid annuloplasty (67%, 76%, 28%, respectively.) In each group after surgery, end-systolic dimension decreased more than end-diastolic dimension despite reduced mitral regurgitation. Although extended PLV resulted in greater volume reduction and less mitral regurgitation, these patients had delayed recovery and poor survival. Patients with valvular disease had the most advanced myocardial hypertrophy with the best survival, while those with Chagas' disease had more severe myocarditis, interstitial fibrosis, and the poorest survival. CONCLUSION: Lateral PLV improved hemodynamics and functional capacity as much as aneurysmectomy by reducing ventricular volume and mitral regurgitation. Inclusion and exclusion criteria have to be sought to make PLV safer and more effective.     

Surgical ventricular reconstruction and mitral regurgitation: what have we learned from 10 years of experience?

Ischemic mitral regurgitation is functional, and caused predominantly by ventricular dilatation, with secondary functional changes related to annular dilatation, tethering of leaflets from distension, and intraventricular widening between papillary muscles, in the absence of chordal rupture. The treatment includes dealing with the mitral-ventricular interaction by combining surgical ventricular restoration and coronary bypass grafts (CABGs) to alter fiber orientation and muscle nourishment, with annuloplasty, decreasing left ventricle (LV) cavitary volume to reduce abnormal lengthening for tethering, and narrowing the distance between papillary muscles to restore a more normal transverse diameter. These interventions are performed during surgical ventricular restoration (SVR), and the annuloplasty is performed within the ventricle. The cavitary size after SVR must not be restrictive, and methods of patch angulation to restore an elliptic chamber, and interventions to avoid too small a LV cavity are discussed as we summarize 10 years of experience with SVR in 924 patients, and analyze interventions for mitral insufficiency in a recent 3-year subset of 363 patients. The integrated response to the vessel, ventricle, and valve are the central themes of management.     

Surgical treatment for ischemic mitral regurgitation: strategy for a tethered valve.

Recently, ischemic mitral regurgitation (IMR) has been shown to be an individual risk factor for ischemic heart disease. The main mechanism of IMR is tethering of the leaflet secondary to left ventricular (LV) dilatation. In this situation, surgical treatment for IMR has been limited to ring annuloplasty with varying degrees of effectiveness. However, mid-term follow-up studies have shown that the results obtained with this approach are not satisfactory. Therefore, there has been a need to develop additional techniques to achieve more secure repair of IMR. The characteristics of the mitral leaflet configuration in IMR are apical displacement of the leaflets relative to the annulus, concavity of the leaflets, and a dilated annulus. Our basic strategy for a tethered mitral valve is rigid ring annuloplasty and inward correction of the outwardly displaced papillary muscle. For the latter correction, we employ the overlapping method or septal anterior ventricular exclusion (SAVE) procedure for LV volume reduction in cases of broad antero-septal infarction, or elevate the posterior papillary muscle by folding the LV wall at the root of the posterior papillary muscle via a small incision in the inferior wall in cases of infero-posterior infarction. An additional procedure is chordal cutting in combination with rigid ring annuloplasty and papillary muscle imbrication in combination with LV volume reduction. We have successfully combined these methods with the aid of detailed echocardiographic studies in individual patients. However, long-term follow-up will be necessary before this approach can be routinely adopted.     

Mobilization of the anterior mitral leaflet for excision of a left ventricular myxoma.

Left ventricular myxomas are extremely rare. We report use of a left atrial approach with mobilization of the anterior mitral valve leaflet to enhance exposure of the subvalvar region and facilitate excision of a left ventricular myxoma entangled within the chordal apparatus, lying between the anterolateral papillary muscle and the left ventricular wall. The detached mitral leaflet was reattached to the annulus with a continuous suture. The tumor was completely excised, thus avoiding a separate transventricular or transaortic approach.     

Papillary muscle approximation combined with ventriculoplasty in patients with ischemic cardiomyopathy and functional mitral regurgitation: effects on mitral valve and LV shape

Recent studies define functional mitral regurgitation (MR) and worsened left ventricular (LV) systolic indices as the widening of the dimension between papillary muscle heads; consequently, narrowing this distance may improve the mitral valve and LV function. Thirty (22 males; mean age: 57+/-7 years) candidates for CABG underwent ventriculoplasty and in 50% of them papillary muscle approximation was also performed (group 1). All the patients had grade 3 to grade 4 MR with an interpapillary muscle distance of more than 2.5 cm. In group 1 the papillary muscles were drawn together by an encircling loop using a 4-mm Gore-Tex tube or umbilical tape. Mitral annuloplasty and Dor procedures were performed in all the patients. Postoperative echocardiography revealed significant changes in systolic and diastolic sphericity indices in the PMA group. There was one hospital death in each group, and within a short mean follow-up period of 9 months, there were no late deaths. Improvement of NYHA class and MR were significantly better in the PMA group. Papillary muscle approximation in selected patients has a clear effect on the mitral valve and LV shape by reducing tethering and sphericity due to the displacement of the papillary muscles.     

Effect of local annular interventions on annular and left ventricular geometry

OBJECTIVE: Etiology-specific annular interventions and annuloplasty rings are now commercially available for the treatment of different types of mitral regurgitation; however, knowledge concerning the effects of local annular alterations on annular and left ventricular (LV) geometry is limited. METHODS: Seven adult sheep underwent implantation of eight radiopaque markers around the mitral annulus (MA) and eight markers on the LV (four each on two levels: basal and apical), and one on each papillary muscle tip. Trans-annular septal-lateral (SL) sutures were placed between the corresponding markers on the septal and lateral annulus at valve center (CENT) and near anterior (ACOM) and posterior (PCOM) commissures and externalized. Hemodynamic parameters and 4D marker coordinates were measured before and during SL annular cinching ('SLAC'; suture tightening 3-5 mm for 20s) at each suture location. Mitral annular SL diameter, annular area (MAA), and distance from the mid-septal annulus to the LV markers and papillary muscle tips were determined from marker coordinates every 17ms. RESULTS: End-systolic MAA decreased from 5.93+/-1.27 to 5.23+/-1.29(*)cm(2), 5.98+/-1.16 to 5.33+/-1.31(*)cm(2), and 6.30+/-1.65 to 5.61+/-1.37(*)cm(2) for SLAC(ACOM), SLAC(CENT), and SLAC(PCOM), respectively ((*)p<0.05 vs pre-cinching). Each SLAC intervention reduced the SL diameter at all three locations, while both SLAC(ACOM) and SLAC(CENT) affected ventricular geometry, and SLAC(PCOM) only slightly altered valvular-subvalvular distance. Only SLAC(CENT) altered papillary muscle position. CONCLUSIONS: Local annular SL reduction influences remote annular SL dimensions and affects LV geometry. The effect of local annular interventions on global annular geometry and LV remodeling should be considered in surgical or interventional approaches to mitral regurgitation and the design of new annular prostheses as well as supra-annular and sub-annular catheter interventions.     

Surgical treatment of ischemic mitral valve regurgitation.

In cases of old myocardial infarction, the presence of mitral valve regurgitation is one of the predicting factors of long-term prognosis. The mechanism of ischemic mitral regurgitation consists of mitral annular dilatation, left ventricular (LV) dilatation followed by tethering of the mitral valve, etc. Since long-term prognosis of the patients in whom the degree of mitral valve regurgitation is 2+ or more is typically poor, the mitral valve procedure should be considered at the time of coronary artery bypass grafting (CABG) or more. In this type of surgery, the treatment essentially involves the use of an artificial ring implantation as the basic technique. In the chronic stage, a significant degree of mitral regurgitation persists in approximately 20% of the cases if they have been treated by ring annuloplasty alone. Additional surgical procedures that reduce or eradicate the tethering are essential for the control of the regurgitation completely in cases with strong tethering. We recently employed two new surgical techniques, namely, cutting the secondary chordae to the anterior mitral valve leaflet and the anterior and posterior papillary muscle reapproximation. The surgical results of the acute phase appear to be promising; however, the long-term results of such new methods are yet to be determined. If the mitral valve regurgitation cannot be controlled even by various operative techniques of mitral valve repair, mitral valve replacement should be considered. This is because the long-term survival rate of the suboptimal repair surgical patients is lower when compared with that of mitral valve replacement patients.     

Surgical management of ventricular septal defects and mitral regurgitation complicating acute myocardial infarction

Sixteen patients were studied subsequent to the development of acute ventricular septal rupture in 7 and severe mitral regurgitation in 9. These lesions occurred within two weeks of acute myocardial infarctions. Intraaortic balloon assistance was initiated when cardiovascular deterioration occurred, and hemodynamic improvement was obtained in all patients. Shunting through a ventricular septal perforation was reduced during balloon assistance, and mitral regurgitation, when present, was decreased. These effects were short-lived, and the patients were subsequently studied with coronary angiography and ventriculography.Two of 3 patients with anterior ventricular septal defect underwent successful surgical correction. Three patients had attempted closure of inferior ventricular septal defect without success. The fourth patient with an inferior ventricular septal defect died of his lesion without any attempt at surgical repair.Four patients with rupture of the papillary muscle were long-term surgical survivors. Coronary artery bypass grafting was carried out when indicated in these patients. Two of 5 patients with papillary muscle dysfunction who underwent operation during the acute period of their infarction were long-term survivors.The findings suggest that the mechanical lesions of mitral regurgitation and ventricular septal perforation are amenable to surgical intervention if a sufficient amount of residual functional muscle can be preserved in the left ventricle. Intraaortic balloon assistance allows a period of time to stabilize the condition of patients with these lesions, to reduce myocardial ischemia, and to carry out studies to determine the degree of associated coronary artery disease and the extent of irreversible myocardial damage. Based on the findings from these studies, surgical procedures may be selected.     

Ischemic mitral regurgitation: intraventricular papillary muscle imbrication without mitral ring during left ventricular restoration

OBJECTIVES: Functional mitral regurgitation in ischemic cardiomyopathy carries a poor prognosis, and its surgical management remains problematic and controversial. The aim of this study was to report the results of our surgical approach to patients who have had myocardial infarctions and have ventricular dilatation, mitral regurgitation, reduced pump function, pulmonary hypertension and coronary artery disease. This surgical approach consists of endoventricular mitral repair without prosthetic ring, ventricular reconstruction with or without patch, and coronary artery bypass grafting. PATIENTS: Forty-six patients (aged 64 +/- 10 years) with previous anterior transmural myocardial infarction and mitral regurgitation comprised the study group. Indication for surgery was heart failure in 93% of cases; 25 patients were in New York Heart Association functional class IV and 17 were in class III. Mitral regurgitation was moderate to severe in 32 cases (69%). RESULTS: All patients underwent coronary artery bypass grafting, with a mean of 3.2 +/- 1.3 grafts. Associated aortic valve replacement was performed in 4 cases. Global operative mortality rate was 15.2%. End-diastolic and end-systolic volumes significantly decreased after surgery (from 140 +/- 40 to 98 +/- 36 mL/m(2) and from 98 +/- 32 to 63 +/- 22 mL/m(2), respectively, P =.001). Systolic pulmonary pressure decreased significantly (from 55 +/- 13 to 43 +/- 16 mm Hg, P =.001). Ejection fraction did not change significantly. Postoperative mitral regurgitation was absent or minimal in 84% of cases; 1 patient had severe mitral regurgitation necessitating valve replacement. New York Heart Association functional class significantly improved. The mean preoperative functional class was 3.4 +/- 0.6 (median 3, range 2-4); after the operation, this decreased to 1.9 +/- 0.7 (median 2, range 1-3, P <.001). Cumulative survival at a 30-month follow-up was 63%. CONCLUSIONS: Our aggressive, combined surgical approach is aimed at correcting the three components of ischemic cardiomyopathy: relieving ischemia, reducing left ventricular wall tension by decreasing left ventricular volumes, and reducing volume overload and pulmonary hypertension by repairing the mitral valve. Despite a relatively high perioperative mortality rate, surviving patients benefitted from the operation, with improved clinical functional class and thus quality of life.