Mitral valvuloplasty is superior to valve replacement for preservation of left ventricular function: an intraoperative two-dimensional echocardiographic study

[Physiopathology and etiology of mitral insufficiency]

Mitral regurgitation has a complex pathophysiology. It should be assessed from the study of factors influencing regurgitant volume and the evaluation of hemodynamics effects downstream (impact on left ventricular function) and upstream (level of left atrial compliance and pulmonary pressure). The regurgitant volume is larger when the regurgitation time is longer, the regurgitant orifice is bigger and the magnitude of the left ventrico-atrial systolic gradient higher. The study of left ventricular function is difficult, especially in chronic mitral regurgitation where the apparently normal left ventricular systolic function can hide a significant worsening in myocardiacs fibres contractile abilities. With the increase in life expectancy and with the decrease in the incidence of rheumatic fever, aetiologies of mitral regurgitation have changed in the past 30 years. They are now dominated by dystrophic mitral regurgitation and infective endocarditis while rheumatic fever becomes less frequent.

Mitral annuloplasty in patients with ischemic versus dilated cardiomyopathy

OBJECTIVE

Mitral regurgitation is a frequent finding in patients with end-stage cardiomyopathy predicting poor survival. Conventional treatment consists medical treatment or cardiac transplantation. However, despite severely decreased left ventricular function, mitral annuloplasty may improve survival and reduce the need for allografts.

METHODS

From January 1996 to July 2002, 121 patients with severe end-stage dilated (DCM) or ischemic cardiomyopathy (ICM), mitral regurgitation > or =2, and left ventricular ejection fraction < or =30% underwent mitral valve annuloplasty using a flexible posterior ring. DCM was diagnosed in 30 patients (25%), whereas ICM was found in 91 patients (75%). Concomitant tricuspid valve repair was performed in 14 (46.6%) patients in the DCM, and in 11 (12%) in the ICM group (P=0.0001), coronary artery bypass grafting in three (10%) in the DCM, and in 78 patients (86%) in the ICM group (P<0.00001). The mean follow-up time was 567+/-74 days in the DCM and 793+/-63 days in the ICM group (ns).

RESULTS

Early mortality was 6.6% (8/121), and was equal for both groups. Improvement in NYHA class (DCM 3.3+0.1-1.8+/-0.16; ICM from 3.2+0.04 to 1.7+/-0.07) were equal between groups after 1 year. Seventeen (15%) late deaths occurred during the follow-up period. There was no difference in the 2-year actuarial survival between groups (DCM/ICM 0.93/0.85). Risk factors for mitral reconstruction failure, defined as regurgitation > or =2 after 1 year, were preoperative NYHA IV in the DCM group (P=0.03), a preoperative posterior infarction (P=0.025), decreased left ventricular function (P=0.043), larger ring size (P=0.026) and preoperative renal failure (P=0.05) in the ICM group. Risk factors for death were larger ring size (P=0.02) and an increased LVEDD (P=0.027) in the DCM group and the postoperative use of IABP (P=0.002), renal failure (P=0.001), and a larger preoperative LVESD (P=0.035) in the ICM group.

CONCLUSION

Mitral reconstruction with a posterior annuloplasty using a flexible ring is effective in patients with severely depressed left ventricle function and has an acceptable operative mortality. Mid-term results are superior to medical treatment alone and comparable to cardiac transplantation.

The long-term outcome of mitral valve repair for mitral valve prolapse

The rationale of early surgery for severe chronic mitral regurgitation (MR) due to mitral valve prolapse (MVP) has been developed over the past decade on the basis of the understanding of the natural history of this disease and the predictors of outcomes after surgical correction of MR. The important decrease in operative mortality associated with the advancements in myocardial preservation, and more importantly the improved reparability of the myxomatous mitral valve, were an additional incentive to develop the concept of early surgery. Previous studies showed that mitral valve repair offers a survival advantage at short- and 10-year follow-up, and therefore suggested that it should be the treatment of choice for severe MR due to MVP. Moreover, very recent data provided new insight on the very long-term follow up, ie, beyond the usual first 10 years in which the initial survival benefit of repair may be negated by a late deterioration.

Surgical alternatives for heart failure

Heart failure is one of the leading causes of hospitalization in the United States. Congestive heart failure is a chronic, progressive disease and its central element is remodeling of the cardiac chamber associated with ventricular dilation. Secondary mitral regurgitation is a complication of end-stage cardiomyopathy and is associated with poor prognosis. Historically, these patients were not considered operative candidates because of their high morbidity and mortality. Heart transplantation is now considered standard treatment for select patients with end-stage heart disease; however, it is applicable only to a small number of patients. In an effort to address this problem, newer and alternative surgical approaches are evolving, including mitral valve annuloplasty, the Batista procedure, and other left ventricular shape changing technologies. Using these operative techniques to alter the shape of the left ventricle, in combination with optimal medical management for heart failure, improves survival, and patients may avoid or postpone transplantation.

Effect of mitral valve surgery on exercise capacity, ventricular ejection fraction and neurohormonal activation in patients with severe mitral regurgitation

OBJECTIVES

The purpose of this study was to prospectively investigate the effects of surgical correction of mitral regurgitation (MR) on exercise performance, cardiac function and neurohormonal activation.

BACKGROUND

Little is known about the effect of surgical correction of MR on functional status or on neurohormonal activation.

METHODS

Cardiopulmonary exercise test, radionuclide angiography and blood samples for assessment of neurohormonal status were obtained in 40 patients with nonischemic MR before and within one year (216+/-80 days) after surgery. Twenty-four patients underwent mitral valve repair (MVr), and 16 underwent valve replacement (VR) with anterior chordal transection.

RESULTS

Despite an improvement in New York Heart Association functional class, exercise performance did not change (peak oxygen consumption: 19.3+/-6.1 to 18.5+/-5.6 ml/kg/min, percentage of maximal predicted oxygen consumption: 79.5+/-18.2% to 76.8+/-16.9%). After surgery, left ventricular (LV) ejection fraction (EF) decreased (64.2+/-10.3% to 59.9+/-11.4%, p = 0.003) while right ventricular (RV) EF increased (41.4+/-9.6% to 44.7+/-9.5%, p = 0.03). Left ventricular EF did not change after MVr (64.3+/-11.5% to 61.5+/-12.2%), but RVEF improved (40.4+/-9.2% to 46.0+/-10.0%, p = 0.02). In contrast, VR was associated with an impairment of LV function in the apicolateral area and a decrease in LVEF (64.1+/-8.5% to 57.4+/-10.0%, p = 0.01), whereas RVEF did not change (42.9+/-10.3% to 42.8+/-8.6%). Moreover, there was only a slight decrease in neurohormonal activation after surgery.

CONCLUSIONS

Despite an improvement in symptomatic status, exercise performance was not improved seven months after either MVr or VR for MR, and neurohormonal activation persisted. Compared with MVr, VR resulted in a significant impairment of cardiac function in this study.

Mitral valve repair in heart failure

Mitral regurgitation (MR) is a frequent complication of end-stage heart failure. Historically, these patients were either managed medically or with mitral valve replacement, both associated with poor outcomes. Mitral valve repair via an 'undersized' annuloplasty repair is safe and effectively corrects MR in heart-failure patients. All of the observed changes contribute to reverse remodeling and restoration of the normal left-ventricular geometric relationship. Mitral valve repair offers a new strategy for patients with MR and end-stage heart failure.

Mitral valve surgery in patients with severe left ventricular dysfunction

OBJECTIVES

The objectives of this study were to determine (1) survival, (2) functional status and freedom from readmission for heart failure and (3) change in postoperative left ventricular (LV) dimensions and function following mitral valve repair or replacement in patients with severe LV dysfunction and mitral regurgitation.

PATIENTS AND METHODS

Between 1990 and 1998, 44 patients with mitral regurgitation and a LV ejection fraction <35% (mean+/-SD, 28+/-6%) underwent isolated mitral repair (n=35) or replacement (n=9). The etiology of regurgitation was valvular in 18 (40%) patients, ischemic in 13 (30%) patients and dilated idiopathic cardiomyopathy in 13 (30%) patients. Every patient had been hospitalized one to six times for symptoms of heart failure (mean+/-SD, 2.3+/-1.5). All patients were receiving maximal drug therapy with 15 (34%) in New York Heart Association (NYHA) class III and 12 (27%) in class IV. Seven (16%) patients were initially referred for consideration of transplantation. The mean+/-SD duration of follow-up was 40+/-21 months.

RESULTS

One (2.3%) patient died 9 days postoperatively of acute bronchopneumonia. The mean+/-SD duration of ICU and hospital stay was 41+/-34 h and 9+/-3 days, respectively. The 1-, 2- and 5-year survival rates were 89, 86 and 67%, respectively. Heart failure and sudden death accounted for 62% of the late deaths. The NYHA class improved for survivors from 2.8+/-0.8 preoperatively to 1. 2+/-0.5 at follow-up (P<0.0001). Freedom from readmission for heart failure was 88, 82 and 72% at 1, 2 and 5 years, respectively. No patient has been listed for transplantation.

CONCLUSIONS

Mitral valve surgery offers symptomatic improvement and survival benefit in patients with severe LV dysfunction and mitral regurgitation. More liberal use of this surgery for cardiomyopathy patients is warranted.

Surgical approaches to dilated cardiomyopathy

Heart failure is one of the leading causes of hospitalization in the United States today. Congestive heart failure is a chronic progressive disease with the common central element being the remodeling of the cardiac chamber associated with ventricular dilation. Secondary mitral regurgitation is a complication of end-stage cardiomyopathy and is associated with a poor prognosis. Historically, these patients were not considered operative candidates due to the high morbidity and mortality in this patient population. Heart transplantation is now considered the standard of treatment for select patients with end-stage heart disease, however, it is only applicable to a small number of patients. In an effort to address this problem, newer and alternative surgical approaches are evolving, including mitral valve annuloplasty, the Batista myoplasty, and cardiomyoplasty. When these operative techniques that alter the shape of the left ventricle are utilized, in combination with optimal medical management for heart failure, survival is improved and patients can avoid or postpone transplantation.

Effects of mitral valve replacement on regional left ventricular systolic strain

BACKGROUND

Mitral valve replacement (MVR) with chordal excision impairs left ventricular (LV) systolic function, but the responsible mechanisms remain incompletely characterized. Loss of normal annular-papillary continuity also adversely affects LV torsional deformation, possibly due to changes in myocardial fiber contraction pattern.

METHODS

Twenty-seven dogs underwent insertion of LV myocardial markers and a sham procedure (cardiopulmonary bypass, no MVR, n = 6), conventional MVR with chordae tendineae excision (n = 7), or chordal-sparing MVR with reattachment of the anterior leaflet chordae to the anterior annulus (n = 7) or to the posterior annulus (n = 7). In the anterior, lateral, posterior, and septal LV regions, linear chords were constructed from each region's central marker to its surrounding markers. Percent systolic shortening (regional LV strain) was calculated for each chord, and the chords were assigned to one of four angular groups: I, left-handed oblique (subepicardial fiber direction); II, circumferential (midwall); III, right-handed oblique (subendocardial); or IV, longitudinal. Regional LV strain data were compared before and after MVR.

RESULTS

Sham and anterior chordal-sparing MVR had minimal effects on regional LV strain. With posterior chordal-sparing MVR: anteriorly, left-oblique (I) strain fell (31%, p<0.05), as did circumferential (II) and right-oblique (III) strains (by 49% and 51%, respectively; p<0.01). Laterally, left-oblique (I) strain fell by 36% (p<0.05), as did longitudinal (IV) strain (54% decline, p<0.01). Conventional MVR with chordal excision disrupted regional fiber shortening diffusely, affecting oblique fibers (I and III) in the anterior and septal regions and impairing longitudinal (IV) strain in all regions (45% to 68% fall, p<0.05).

CONCLUSIONS

Sham and anterior chordal-sparing MVR did not substantially alter regional LV strain; however, loss of normal anatomic valvular-ventricular integrity (conventional MVR) or posterior chordal-sparing MVR resulted in pronounced alterations in LV strain, most notably in the longitudinal and oblique fiber directions. These findings demonstrate that the deleterious effects of chordal excision are associated with perturbed internal myocardial systolic deformation, which suggests that chordal disruption distorts myofiber architecture or regional systolic loading.

Management of mitral regurgitation. Optimal timing for surgery

Chronic mitral regurgitation is a progressive disorder that can produce myocardial dysfunction in the absence of symptoms. Improvements in surgical techniques have resulted in earlier intervention, at times in asymptomatic patients. This article discusses the factors that influence prognosis, reviews the evidence supporting earlier intervention and provides guidelines for the management of patients with this lesion.

Treatment of chronic mitral regurgitation

BACKGROUND

Chronic, severe mitral regurgitation is a common clinical entity that can lead to progressive, irreversible left ventricular dysfunction. New information on the natural history of this condition, coupled with advances in surgical technique, have changed the roles of medical and surgical therapies.

METHODS

The current medical and surgical literature regarding chronic mitral regurgitation is critically reviewed.

RESULTS

There is no well-defined role for medical therapy in chronic mitral regurgitation. The goal of the treating physician is therefore to choose the optimal timing for surgical intervention. This process begins with noninvasive quantification of the degree of regurgitation. If severe, a careful search for signs or symptoms of impending left ventricular dysfunction should follow. Recent advances in surgical techniques for mitral valve repair allow for correction of the valvular defect with minimal mortality risk and improved preservation of ventricular function and are an impetus for early operative intervention. Mitral valve repair may also be beneficial in the setting of severe dilated cardiomyopathy.

CONCLUSIONS

The development of techniques for mitral valve repair has altered the treatment paradigm for severe mitral regurgitation. Surgical intervention before the onset of left ventricular dysfunction is recommended.

Clinical evaluation of the Physio annuloplasty ring

STUDY OBJECTIVES

Prospective evaluation of a selectively flexible annuloplasty ring was undertaken to assess its safety and efficacy.

PATIENTS

Between December 1992 and November 1996, 190 patients with mitral regurgitation underwent mitral valve repair using an annuloplasty ring (Carpentier-Edwards Physio; Baxter-Edwards CVS Laboratories; Irvine, Calif). Ninety-four were in New York Heart Association class I or II. Etiology was degenerative in 74% of the patients.

RESULTS

Four patients died early for a hospital mortality of 2.1%, and one late death occurred. Two patients with systolic anterior motion required early valve replacement. Two transient episodes of hemiparesis occurred during the first postoperative month. There were no late thromboembolic complications, no late reoperation, and no endocarditis. Mean follow up of 23+/-13 months was complete in 99% of the patients. Seventy-seven patients (40.5%) have had Doppler echocardiography > 1 year after surgery: 61 (80%) of them have no residual regurgitation, 15 have grade 1+/4+ mitral regurgitation, while 1 has grade 2+/4+ insufficiency. Left ventricular end-diastolic volume index (mL/lm2) decreased from 107.4+/-35.5 preoperatively to 74.2+/-24.4 at last control (p<0.001).

CONCLUSION

The physio annuloplasty ring provided reliable and stable results at medium-term follow-up with a very low incidence of valve-related complications.

Comparison of outcomes of percutaneous mitral valvuloplasty versus mitral valve replacement after resolution of left atrial appendage thrombi by warfarin therapy

This study assesses the efficacy of oral anticoagulation in resolving left atrial appendage (LAA) thrombi and evaluates clinical outcomes of percutaneous mitral valvuloplasty after resolution of LAA thrombi compared with mitral valve replacement. Warfarin therapy is successful in resolving LAA thrombi; percutaneous mitral valvuloplasty after resolution of LAA thrombi is an effective alternative to surgical treatment.

Continuous transoesophageal echocardiography monitoring during weaning from cardiopulmonary bypass in children

The purpose of this study was to evaluate the effectiveness of transoesophageal echocardiography monitoring during weaning from cardiopulmonary bypass after intracardiac repair in children. The left ventricular ejection fraction, left ventricular end-diastolic volume and left ventricle wall motion were monitored continuously by transoesophageal echocardiography in controls weaned easily from cardiopulmonary bypass (group A, n = 25), and those weaned with difficulty from cardiopulmonary bypass after mechanically assisted circulation (group B, n = 16). In group A, left ventricular ejection fraction and left ventricle wall motion were within normal range, and did not change significantly during weaning after cardiopulmonary bypass when compared with pre-bypass data. In contrast, left ventricular ejection fraction, left ventricular end-diastolic volume and left ventricle wall motion in group B during the first trial of weaning from bypass were significantly worsened. Hence, assisted circulation was performed until the data obtained via transoesophageal echocardiography improved with regard to maintenance of fluid balance, catecholamine dosage and assisted pump flow. All cases in group B were weaned safely from cardiopulmonary bypass despite their critical condition. In conclusion, continuous transoesophageal echocardiography monitoring may be a useful tool in children with severe heart failure for safe weaning from cardiopulmonary bypass after intracardiac repair.

Role of cAMP in modulating relaxation kinetics and the force-frequency relation in mitral regurgitation heart failure

The report is a discussion of previously published and newly analyzed results concerning the association between heart diseases and alterations in the force-frequency relation (FFR). The optimum stimulation frequency of the FFR is measured and compared in isolated left ventricular myocardium from non-failing hearts with atrial septal defect, coronary artery disease (without and with insulin dependent diabetes mellitus) and from failing hearts with mitral regurgitation, or idiopathic dilated cardiomyopathy. Specifically, we examine the role of altered control of the excitation-contraction coupling system in blunting the force-frequency relation. We use the percent slope of the FFR as a measure of changes in the frequency sensitivity of this control. Our finding of a linear, direct relation between optimum stimulation frequency and % slope across all disease types suggests both parameters are coupled to the same underlying mechanism. To investigate the possible role of altered control of the calcium pump in this mechanism, we analyzed the detailed relation between isometric twitch relaxation kinetics and stimulation frequency in mitral regurgitation myocardium (MR). In the presence of 0.5 microM forskolin the depressed slope and optimum frequency of the FFR and the prolonged half-time of twitch relaxation were all restored to values found in non-failing myocardium. We use the kinetics of isometric twitch relaxation as an index of changes in pumping rate that occur in response to changes in stimulation frequency or in intracellular cyclic adenosine monophosphate concentration. A mathematical model based on the Hill relations for calcium pump uptake rate and for isometric tension as a function of intracellular pCa is developed to simulate isometric twitch relaxation in MR and non-failing myocardium. The success of this model in simulating non-failing and failing twitch relaxation supports a proposed mechanism for the prolonged relaxation time and depressed FFR in MR involving depressed protein kinase-A activity (due to lowered cAMP or to a defect in the Ser16 site of phospholamban) as a mechanism of altered control of the calcium pump in MR heart disease.

Nonreplacement operations for mitral valve regurgitation

Mitral valve reconstruction offers patients an important alternative to the traditional method for treating severe mitral regurgitation--mitral valve replacement. Over the last 15 years, surgical techniques have evolved for treating mitral regurgitation occurring from various anatomic mechanisms--annular dilatation, abnormal leaflet motion due to a variety of causes, or leaflet perforation. Currently, over 90% of regurgitant mitral valves of varying etiologies are amenable to nonreplacement therapy by reconstruction, with good intermediate- and long-term results. Reconstruction obviates the need for long-term anticoagulation, and thus, there has evolved a trend toward reconstruction earlier in the course of this disease, before fixed atrial fibrillation and ventricular dilatation occur.

Reoperation after valve repair for mitral regurgitation: early and intermediate results

To better understand late outcomes of mitral valve repair, we reviewed the cases of 49 consecutive patients who underwent reoperation between January 1974 and May 1992 for recurrent valve dysfunction after previous valvuloplasty for mitral regurgitation. There were 27 men (55%) and 22 women, with a median age of 63 years (range 20 to 84 years). Original procedures included annuloplasty and posterior leaflet repair in 15 patients (31%), annuloplasty and anterior leaflet repair in 15 (31%), commissural plication in 13 (27%), and complex bileaflet repairs in six (12%). Median time between initial mitral repair and reoperation was 2.4 years (range 2 months to 25.3 years). Indications for reoperation included recurrent severe mitral regurgitation in 34 patients (70%), hemolytic anemia from mitral regurgitation in seven (14%), mixed mitral regurgitation and stenosis in seven (14%), and isolated mitral stenosis in one (2%). Before reoperation, 36 patients were in New York Heart Association functional class III and 11 were in class IV. Initial repairs were intact at the second operation in 32 patients (65%), and the etiology of recurrent mitral regurgitation in these patients was fibrosis or calcification of the anulus or leaflets in 22 patients, newly ruptured chordae in seven, and perforated leaflets in three. The causes of mitral regurgitation in the 17 patients whose initial repair had failed included dehiscence of commissural repairs in nine patients, dehiscence of ring annuloplasty in four, and break-down of chordal or leaflet repair in four. Patients with original repairs involving the anterior leaflet had a significantly shorter time between operations (p = 0.006). In eight patients (16%), the mitral valve was repaired again; in the remaining 41 patients (84%), prosthetic replacement was performed. Operative mortality rate was 4% (two patients). All eight patients who underwent mitral valve rerepair had no mitral regurgitation, trivial regurgitation, or mild regurgitation at discharge from the hospital. Follow-up was 100% complete at a mean of 5.1 years (range 1 to 19 years). Forty-one patients (87% were in New York Heart Association functional class I or II, and survival at 5 years was 75.3%. Of the eight patients who underwent a second repair, seven had no regurgitation, trivial regurgitation, or mild regurgitation at a median of 4 years' follow-up. The low mortality associated with reoperation supports an aggressive approach toward mitral regurgitation with initial repair. A second repair can be performed in selected patients with durable results at 4 years.

Mitral valve repair is superior to valve replacement for the early preservation of cardiac function: relation of ventricular geometry to function

The immediate effect or mitral valve repair (MVP) or replacement (MVR) on cardiac function was compared in patients with mitral regurgitation in relation to the changes in left ventricular (LV) function and geometry by using intraoperative transesophageal echocardiography in 29 patients with MVP and 21 patients with MVR, before and immediately after cardiopulmonary bypass. The LV volumes, ejection fraction, and long-axis and short-axis lengths and eccentricity index (ratio of long axis to short axis) at end-systole and end-diastole were measured. After both MVP and MVR, there were significant decreases in LV end-diastolic volume (p < 0.0001). However, the ejection fraction did not change after MVP, whereas it decreased after MVR (p < 0.0001). After MVP, there was an increase in eccentricity index at end-systole (p < 0.0001). After MVR, there was no decrease in end-systolic volume, and the eccentricity index was lower than that after MVP (p < 0.0001). The change in LV ejection fraction correlated with the changes in eccentricity index at end-systole (r = 0.55; p < 0.0001) and end-diastole (r = 0.42; p < 0.0003). Immediate intraoperative LV function is preserved after MVP but is depressed after MVR for mitral regurgitation. The changes in ejection fraction correlate with changes in ventricular geometry.

Transesophageal echocardiographic evaluation of native valvular disease and repair

Surgery for valvular heart disease corrects systolic or diastolic dysfunction of the mitral, aortic, or tricuspid valves. The intraoperative echocardiographic assessment of the native heart valve is aimed at defining the pathology of valve disease, determining the mechanism of valve dysfunction, and quantitating the degree (grade) of valvular stenosis or insufficiency.

Extensive calcification of the mitral valve anulus: pathology and surgical management

Extensive calcification of the mitral valve anulus is a pathologic entity frequently associated with degenerative valvular disease. The calcification process remains localized to the anulus in 77% of the cases. It may extend, however, to the underlying myocardium. Whenever an operation is necessary for an associated valve insufficiency, the question arises whether it is preferable to repair or to replace the valve and how to manage the calcification. In the first part of this paper the pathology of this disease is studied, and in the discussion a mechanism is proposed to explain the development of the process of calcification. In the second part, a new operation is described, which comprises the temporary detachment of the leaflets, en bloc resection of the calcium deposit, annular reconstruction, and valve repair. For patients in whom the calcification extends to the myocardium a "sliding atrioplasty" of the left atrium is described, which allows the area of exposed muscular fibers to be covered. Between 1986 and 1994, among 68 patients with extensive calcification of the anulus and severe mitral valve insufficiency, 67 benefited from these repair techniques. Ages ranged from 18 to 82 years (mean 62 years). Thirty-two patients had a billowing mitral valve (Barlow), 27 a fibroelastic deficiency, and two Marfan's disease. The calcification involved more than one third of the anulus in 88% of the patients, the posterior anulus in 10.5%, and the whole anulus in 1.5%. The calcification process extended to the myocardial wall in 12% of the patients and to the papillary muscles in 4.5%. In the group of 67 valve repairs, there were two hospital deaths (2.9%), no instances of anulus dehiscence, and no early reoperations. The follow-up period extended from 4 months to 8 years (mean 3 years 8 months). There were two late deaths, 2 and 17 months after the operations, for an actuarial survival of 93% at 7 years. Late reoperation (6 to 62 months) was necessary in four patients (6.4%) for residual mitral valve incompetence (n=2), hemolysis (n=1), or endocarditis (n=1). In one of these patients a new repair was possible, whereas the three other patients required a valve replacement. All patients but one survived the reoperation. Actuarial freedom from reoperation was 87% at 7 years. All 60 patients with valve repair were reviewed for this study by clinical examination and echocardiography. All but one were in functional class I or II. There was no incompetence or trivial residual mitral valve incompetence in 55 patients and moderate incompetence in five. Two thromboembolic events have been recorded for a linearized rate of 1%/pt-yr. This study shows that complete anulus decalcification and valve repair can be done safely in patients with mitral valve insufficiency and extensive calcification of the anulus, even when the calcification process deeply involves the myocardium. It also demonstrates that an initially good result remained stable up to 7 years.

Preservation of left ventricular function in mitral valve surgery

Surgery for degenerative mitral regurgitation has become complex. Preservation of annulo-ventricular continuity through the chordae tendineae is an important determinant of operative survival, postoperative left ventricular function, long-term survival, and quality of life. Some cardiologists believe that NYHA I function is never achieved after conventional mitral replacement with chordal transection. Valve repair is the procedure of choice but when valve replacement is inevitable every effort should be made to preserve the posterior leaflet and its chordal attachments. Valve replacement with preservation of the subvalvar apparatus provides a functional outcome similar to that after valve repair but usually leads to life long anti-coagulation.

Enhanced regional deformation at the anterior papillary muscle insertion site after chordal transsection

BACKGROUND

Clinical and experimental studies of mitral valve replacement have shown a depression of ventricular function after chordal transsection; most recent studies have proposed that this is secondary to a depression of local function near the papillary muscle insertion site. However, there is no direct experimental evidence for changes in local fiber shortening in the wall of the left ventricle overlying the papillary muscle. Accordingly, we investigated the effect of chordal transsection on left ventricular shape and on three-dimensional regional deformation of the myocardium near the insertion of the anterior papillary muscle.

METHODS AND RESULTS

In six open-chest dogs, two sets of three transmural columns of radiopaque markers were implanted in the anterior wall, one set at the tip of the papillary muscle (basal) and one at the site of papillary muscle fiber insertion (apical). A Björk-Shiley mitral valve was placed in the left atrium adjacent to the native valve. Markers were then tracked with biplane cineradiography, and deformation was quantified with the use of finite strain analysis. Chordal transection resulted in reduced left ventricular end-systolic pressure and slowed relaxation. After chordal transsection, outward displacement of the ventricular wall and transverse shearing deformation were observed in the area of the papillary muscle during isovolumic contraction. Circumferential and radial strains during ejection were maintained at our basal site and enhanced on our apical site.

CONCLUSIONS

Chordal transsection led to enhanced local shortening and wall thickening and regional strain nonuniformity. These results indicate that chordal transsection induces an unloading of myocardium at the papillary muscle insertion site and that the resulting heterogeneity of regional function is the mechanism for the reduced global function and slowed ventricular relaxation.

Mitral valve reconstruction in elderly, ischemic patients

The role of mitral valve reconstruction is controversial in elderly patients with concurrent ischemic heart disease owing to technical difficulty, prolonged operative times, high mortality, and possible residual mitral regurgitation. However, mitral reconstruction could be most beneficial in this age group due to preservation of left ventricular function, avoidance of anticoagulation, or repeat operation for bioprosthetic degeneration. We studied the outcome of mitral valve reconstruction in 100 consecutive elderly ischemic patients 65 years or older (mean = 73 years; range, 65 to 86 years) operated on between October 1990 and May 1995. Preoperatively all patients were New York Heart Association (NYHA) class III or IV with an ejection fraction of 32 +/- 2%. All patients underwent primary coronary bypass grafting (2.7 +/- 0.2 grafts) and had a flexible mitral annuloplasty ring inserted. Additionally, 54 patients required further complex mitral repairs. All patients had 4+ mitral regurgitation by transesophageal echocardiography prior to operation. After mitral reconstruction, no patient had more than 1+ regurgitation, while most had none and no systolic anterior leaflet motion was noted. There were 4 early (30 day) deaths (4%) and 6 late deaths (6%) at a mean follow-up of 25 months. Patient morbidity has included episodes of mild congestive heart failure (nine), transient ischemic attack (one), endocarditis (one), and respiratory failure (five). There have been one early and two late reoperations for mitral valve replacement. All remaining patients are in NYHA class I or II. While longer-term follow-up is mandatory, coronary bypass grafting and mitral valve reconstruction in the elderly can be accomplished with acceptable surgical mortality and morbidity, yielding reliable improvement in symptoms and quality of life.

A comparison of transesophageal and transthoracic echocardiographic assessment of left ventricular function in pediatric patients with congenital heart disease

OBJECTIVE

To determine the quantitative utility of transesophageal echocardiographic assessments of left ventricular function in pediatric patients with congenital heart disease by evaluating the variability between observers and between echocardiographic windows.

DESIGN

Retrospective, blinded analysis.

SETTING

University-associated pediatric hospital.

PARTICIPANTS

Transthoracic and transesophageal echocardiographic images of 25 pediatric patients with congenital heart disease were reviewed.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

End-diastolic area, end-systolic area, and fractional area change were measured from short-axis images of the left ventricle at the midpapillary level by two separate investigators. These measurements were compared by the method of Bland and Altman and Sheiner and Beal. Significant differences in measurements of end-diastolic and end-systolic area by different observers were noted, but they were systematic. A similar situation was noted for the comparison of transthoracic and transesophageal measurements of end-diastolic and end-systolic area. In the comparison of fractional area change between observers or windows, bias and absolute prediction error were lower, with 95% confidence limits of bias or absolute prediction error of 10% or less.

CONCLUSIONS

The potential error in the measurement of fractional area change in 10% under optimal conditions. This would suggest that the assessment of ventricular function in the operating room or intensive care unit, under less than optimal conditions, should be viewed as a qualitative, rather quantitative, measurement. There may be significant interobserver and interwindow variability.

Congestive heart failure after surgical correction of mitral regurgitation. A long-term study

BACKGROUND

In patients with mitral regurgitation, surgical intervention produces immediate improvement in symptoms, but the long-term incidence and significance of postoperative congestive heart failure are unknown.

METHODS AND RESULTS

The long-term outcome of 576 operative survivors of surgical correction of pure mitral regurgitation performed between 1980 and 1989 was analyzed. Survival was 77 +/- 2% and 56 +/- 3% at 5 and 10 years, respectively. Cumulative incidence of congestive heart failure was 23 +/- 2%, 33 +/- 3%, and 37 +/- 3% at 5, 10, and 14 years, respectively. Survival after the first episode of congestive heart failure was dismal, 44 +/- 4% at 5 years. Cause of congestive heart failure was left ventricular dysfunction in two thirds of the patients and valvular dysfunction in the other third. With multivariate analysis, the independent predictors of postoperative heart failure were preoperative ejection fraction (P = .0001), coronary artery disease (P = .0017), and New York Heart Association functional class (P = .012), with borderline value for atrial fibrillation (P = .10). The performance of valve repair was independently predictive of a lower incidence of the combined end point of death and heart failure (P = .001), compared with valve replacement.

CONCLUSIONS

Congestive heart failure frequently occurs late after surgical correction of mitral regurgitation and portends dismal prognosis. This complication is due most often to left ventricular dysfunction; its main determinant is decreased left ventricular function preoperatively. These data should lead to earlier indication of surgical correction of mitral regurgitation, before left ventricular dysfunction occurs.

Early improvement in congestive heart failure after correction of secondary mitral regurgitation in end-stage cardiomyopathy

Mitral regurgitation frequently complicates dilated cardiomyopathy, aggravates volume overload of the left ventricle, and contributes to symptoms of congestive heart failure. This study was performed to assess the impact of mitral valve reconstruction in nine consecutive patients with severe mitral regurgitation resulting from end-stage dilated cardiomyopathy. Clinical and echocardiographic follow-up were obtained 17 +/- 5 and 16 +/- 6 weeks after surgery, respectively. There were no operative or early deaths. All patients noted symptomatic improvement postoperatively, and there was a decrease of at least one New York Heart Association functional class (3.9 +/- 0.3 to 1.7 +/- 0.5, p < 0.001). Quantitative echocardiography/Doppler demonstrated a small but significant decrease in left ventricular end-diastolic volume (317 +/- 111 ml to 291 +/- 105 ml, p = 0.04) and increases in ejection fraction (18 +/- 5% to 24 +/- 9%, p = 0.02) and forward cardiac output (3.1 +/- 1.0 to 4.6 +/- 0.8 L/min, p < 0.01) on follow-up. Mitral valve reconstruction for the correction of mitral regurgitation in patients with end-stage dilated cardiomyopathy results in improved symptomatic status on early follow-up accompanied by evidence of improvement in left ventricular performance.

Early outcome of mitral valve reconstruction in patients with end-stage cardiomyopathy

Uncontrollable severe mitral regurgitation is a frequent complication of end-stage cardiomyopathy, significantly contributing to heart failure in these patients, and predicts a poor survival. Although elimination of mitral valve regurgitation could be most beneficial in this group, corrective mitral valve surgery has not been routinely undertaken in these very ill patients because of the presumed prohibitive operative mortality. We studied the early outcome of mitral valve reconstruction in 16 consecutive patients with cardiomyopathy and severe, refractory mitral regurgitation operated on between June 1993 and April 1994. There were 11 men and five women, aged 44 to 78 years (64 +/- 8 years) with left ventricular ejection fractions of 9% to 25% (16% +/- 5%). Preoperatively all patients were in New York Heart Association class IV, had severe mitral regurgitation (graded 0 to 4+ according to color flow Doppler transesophageal echocardiography) and two were listed for transplantation. Operatively, a flexible annuloplasty ring was implanted in all patients. Four patients also had single coronary bypass grafting for incidental coronary disease. In four patients the operation was performed through a right thoracotomy because of prior coronary bypass grafting, and four patients also underwent tricuspid valve reconstruction for severe tricuspid regurgitation. No patient required support with an intraaortic balloon pump. There were no operative or hospital deaths and mean hospital stay was 10 days. There were three late deaths at 2, 6, and 7 months after mitral valve reconstruction, and the 1-year actuarial survival has been 75%. At a mean follow-up of 8 months, all remaining patients are in New York Heart Association class I or II, with a mean postoperative ejection fraction of 25% +/- 10%. There have been no hospitalizations for congestive heart failure, and a decrease in medications required has been noted. For patients with cardiomyopathy and severe mitral regurgitation, mitral valve reconstruction as opposed to replacement can be accomplished with low operative and early mortality. Although longer term follow-up is mandatory, mitral valve reconstruction may allow new strategies for patients with end-stage cardiomyopathy and severe mitral regurgitation, yielding improvement in symptomatic status and survival.

Valve repair improves the outcome of surgery for mitral regurgitation. A multivariate analysis

BACKGROUND

Mitral valve repair has been suggested as providing a better postoperative outcome than valve replacement for mitral regurgitation, but this impression has been obscured by differences in baseline characteristics and has not been confirmed in multivariate analyses.

METHODS AND RESULTS

The outcomes in 195 patients with valve repair and 214 with replacement for organic mitral regurgitation were compared using multivariate analysis. All patients had preoperative echocardiographic assessment of left ventricular function. Before surgery, patients with valve repair were less symptomatic than those with replacement (42% in New York Heart Association functional class I or II versus 24%, respectively; P = .001), had less atrial fibrillation (41% versus 53%; P = .017), and had a better ejection fraction (63 +/- 9% versus 60 +/- 12%, P = .016). After valve repair, compared with valve replacement, overall survival at 10 years was 68 +/- 6% versus 52 +/- 4% (P = .0004), overall operative mortality was 2.6% versus 10.3% (P = .002), operative mortality in patients under age 75 was 1.3% versus 5.7% (P = .036), and late survival (in operative survivors) at 10 years was 69 +/- 6% versus 58 +/- 5% (P = .018). Late survival after valve repair was not different from expected survival. After surgery, ejection fraction decreased significantly in both groups but was higher after valve repair (P = .001). Multivariate analysis indicated an independent beneficial effect of valve repair on overall survival (hazard ratio, 0.39; P = .00001), operative mortality (odds ratio, 0.27; P = .026), late survival (hazard ratio, 0.44; P = .001), and postoperative ejection fraction (P = .001).

CONCLUSIONS

Valve repair significantly improves postoperative outcome in patients with mitral regurgitation and should be the preferred mode of surgical correction. The low operative mortality is an incentive for early surgery before ventricular dysfunction occurs.

Mitral valve replacement with complete retention of native leaflets

Although both mitral leaflets contribute equally to the preservation of left ventricular function after mitral valve replacement, most surgeons routinely excise the anterior mitral leaflet. Possible disadvantages of leaflet retention are left ventricular outflow tract obstruction and interference with prosthetic valve motion. In 31 patients undergoing mitral valve replacement, all mitral valvular and subvalvular tissue was completely retained using a technique that involved reefing the native leaflets into the valve sutures. Fifteen Carpentier-Edwards porcine and 16 St. Jude Medical valves were implanted. Two patients died of causes unrelated to this technique. In the others, echocardiography demonstrated either no or an insignificant left ventricular outflow tract gradient, and, in most, no valvular tissue could be seen in the left ventricular outflow tract. No interference with prosthetic leaflet mobility occurred. The salutary results of mitral valve replacement with complete leaflet retention recommend its use.

Regression of left ventricular mass after mitral valve repair of pure mitral regurgitation

To evaluate the effect of mitral valve repair on the regression of left ventricular mass, we studied 50 consecutive patients with severe, pure mitral regurgitation undergoing mitral valve repair. Two-dimensional echocardiograms were recorded a mean 2.5 +/- 2.0 weeks before and 6.5 +/- 2.5 months after valve operation. Postoperative significant mitral regurgitation was present in 3 patients. After mitral valve repair there were significant decreases in left ventricular end-diastolic volume index (133 +/- 39 mL/m2 to 79 +/- 35 mL/m2; p < 0.001), end-systolic volume index (44 +/- 26 mL/m2 to 30 +/- 26 mL/m2; p < 0.001), stroke volume index (89 +/- 29 mL/m2 to 49 +/- 19 mL/m2; p < 0.001), and mass index (211 +/- 82 g/m2 to 134 +/- 52 g/m2; p < 0.001). There also were significant decreases in left atrial dimension (47 +/- 9 mm to 38 +/- 9 mm; p < 0.001), left ventricular end-diastolic dimension (61 +/- 8 mm to 48 +/- 7 mm; p < 0.001), and end-systolic dimension (39 +/- 8 mm to 32 +/- 7 mm; p < 0.001). Left ventricular ejection fraction decreased slightly from 0.69 +/- 0.12 to 0.64 +/- 0.12; p < 0.01) after repair. Thus, correction of pure mitral regurgitation leads to reduction of the cardiac chamber size and left ventricular volumes as well as regression of the left ventricular mass.

Echocardiographic prediction of left ventricular function after correction of mitral regurgitation: results and clinical implications

OBJECTIVES

This study attempted to determine the incidence, prognosis and predictability of postoperative left ventricular dysfunction in patients undergoing correction of mitral regurgitation.

BACKGROUND

Left ventricular function in patients with mitral regurgitation is altered by loading conditions and is difficult to assess. Predictive value of preoperative variables on postoperative left ventricular function and the role of echocardiography are uncertain.

METHODS

In 266 patients undergoing correction of mitral regurgitation between 1980 and 1989, left ventricular function was echocardiographically assessed preoperatively (within 6 months) and postoperatively (within 1 year).

RESULTS

After correction of mitral regurgitation, left ventricular ejection fraction decreased significantly ([mean +/- SD] 50% +/- 14% vs. 58% +/- 13%, p < 0.0001). Postoperative left ventricular dysfunction (ejection fraction < 50%) was frequent (41% of patients) and carried a poor prognosis (at 8 years survival, 38% +/- 9% vs. 69% +/- 8%, p < 0.0001). Four preoperative echocardiographic variables showed good correlation with postoperative ejection fraction: preoperative ejection fraction (r = -0.70), systolic diameter (r = -0.63), diameter/thickness ratio (r = -0.64) and end-systolic wall stress (r = -0.62) (all p < 0.0001). With multivariate analysis, ejection fraction (p = 0.0001) and systolic diameter (p = 0.0005) were independent predictors of postoperative ejection fraction, and angiographic variables provided no incremental predictive power. In addition to echocardiographic variables, recent regurgitation, functional class and coronary artery disease were also independent predictors of postoperative ejection fraction.

CONCLUSIONS

After surgical correction of mitral regurgitation, left ventricular dysfunction is frequent and carries a poor prognosis. Postoperative ejection fraction can be predicted by echocardiographic preoperative ejection fraction and systolic diameter. Recent onset of regurgitation, mild or no symptoms, and absence of coronary artery disease are independent and favorable predictors of postoperative ejection fraction. These results should lead to consideration of surgical correction at an earlier stage.

Morphology of the mitral valve as displayed by multiplane transesophageal echocardiography

This study was performed to (1) describe how multiplane transesophageal echocardiography (TEE) facilitates imaging of the entire mitral valve apparatus, and (2) prospectively compare the morphology of the different segments of the mitral apparatus as determined by multiplane TEE and direct surgical inspection. The study consisted of 30 consecutive patients examined by multiplane TEE less than 24 hours before mitral valve surgery. The mitral valve was displayed in transgastric and transesophageal views with the imaging planes specifically aligned to demonstrate continuity between the papillary muscles, chordae tendineae, and leaflet edges. The character and location of morphologic abnormalities identified by findings of preoperative TEE were highly concordant with surgical inspection of the valve (p < 0.0001). Thus multiplane TEE offers the ability to visualize the entire mitral apparatus as a functional unit and to identify morphologic abnormalities of the valve correctly.

Natural history of the asymptomatic/minimally symptomatic patient with severe mitral regurgitation secondary to mitral valve prolapse and normal right and left ventricular performance

The natural history of patients with severe nonischemic mitral regurgitation (MR) from mitral valve prolapse, who are asymptomatic or minimally symptomatic and have normal right ventricular (RV) and left ventricular (LV) performance, has not been evaluated previously. To define natural history in this population and to determine if any objective variables could predict disease progression, 31 patients were followed annually with severe MR due to prolapse, who at entry were asymptomatic or minimally symptomatic and had normal RV and LV performance at rest by radionuclide cineangiography. Average follow-up in patients not reaching surgical end point was 4.7 years. The Kaplan-Meier product limit estimates were used to determine the rate of progression to either "operable" symptoms or to previously defined "high risk" ventricular performance descriptors, if the latter occurred first. Univariate comparisons of Kaplan-Meier curves and multivariate Cox proportional hazards analyses were used to define prognostically important variables measured at entry. Fourteen patients developed symptoms warranting referral for operation; none developed high-risk ventricular performance descriptors. The annual end point risk was 10.3%. Of all covariates, only change in RV ejection fraction from rest to exercise was significantly associated with disease progression. Annual risk of progression to surgical end point was 4.9% in the subgroup in which this parameter increased with exercise and 14.7% in the subgroup without an increase (p = 0.04). Patients with severe MR due to mitral valve prolapse, who are asymptomatic or minimally symptomatic with normal ventricular performance, can be expected to progress to surgical indications at an annual rate of 10.3%.(ABSTRACT TRUNCATED AT 250 WORDS)