Mitral valve repair in heart failure

Surgery of secondary mitral insufficiency in patients with impaired left ventricular function

BACKGROUND

Secondary mitral insufficiency (SMI) is an indicator of a poor prognosis in patients with ischemic and dilated cardiomyopathies. Numerous studies corroborated that mitral valve (MV) surgery improves survival and may be an alternative to heart transplantation in this group of patients.The aim of the study was to retrospectively analyze the early and mid-term clinical results after MV repair resp. replacement in patients with moderate-severe to severe SMI and left ventricular ejection fraction (LVEF) below 35%.

METHODS

We investigated 40 patients with poor LVEF (mean, 28 +/- 5%) and SMI who underwent MV repair (n = 26) resp. replacement (n = 14) at the University Hospital Muenster from January 1994 to December 2005. All patients were on maximized heart failure medication. 6 pts. had prior coronary artery bypass grafts (CABG). Twenty-seven patients were in New York Heart Association (NYHA) class III and 13 were in class IV. Eight patients were initially considered for transplantation. During the operation, 14 pts had CABG for incidental disease and 8 had tricuspid valve repair. Follow-up included echocardiography, ECG, and physician's examination and was completed in 90% among survivors. Additionally, the late results were compared with the survival after orthotope heart transplantation (oHTX) in adults with ischemic or dilated cardiomyopathies matched to the same age and time period (148 patients).

RESULTS

Three operative deaths (7.5%) occurred as a result of left ventricular failure in one and multiorgan failure in two patients. There were 14 late deaths, 2 to 67 months after MV procedure. Progress of heart failure was the main cause of death. 18 patients who were still alive took part on the follow-up examination. At a mean follow-up of 50 +/- 34 (2-112) months the NYHA class improved significantly from 3.2 +/- 0.5 to 2.2 +/- 0.4 (p < 0.001). The LVEF improved significantly from 29 +/- 5% to 39 +/- 16 (p < 0.05). There were no differences in survival after MV repair or replacement. The 1-, 3-, 5-year survival rates in the study group were 80%, 58% and 55% respectively. In the group of patients after oHTX the survival was accordingly 72%, 68%, 66% (p > 0.05).

CONCLUSION

High risk mitral valve surgery in patients with cardiomyopathy and SMI offers a real mid-term alternative method of treatment of patients in drug refractory heart failure with similar survival in comparison to heart transplantation.

Mechanisms of valve competency after mitral valve annuloplasty for ischaemic mitral regurgitation using the Geoform ring: insights from three-dimensional echocardiography

AIMS

Left ventricular remodelling leads to functional mitral regurgitation resulting from annular dilatation, leaflet tethering, tenting, and decreased leaflet coaptation. Mitral valve annuloplasty restores valve competency, improving the patient's functional status and ventricular function. This study was designed to evaluate the mechanisms underlying mitral valve competency after the implantation of a Geoform annuloplasty ring using three-dimensional (3D) echocardiography.

METHODS AND RESULTS

Seven patients (mean age of 65 years) with ischaemic mitral regurgitation underwent mitral valve annuloplasty with the Geoform ring and coronary artery bypass surgery. Pre- and post-operative 3D echocardiograms were performed. Following mitral annuloplasty, mitral regurgitation decreased from 3.4+/-0.2 to 0.9+/-0.3 (P-value<0.0001), mitral valve tenting volume from 13+/-1.7 to 3.2+/-0.3 mL (P-value<0.001), annulus area from 12.6+/-1.0 to 3.3+/-0.2 cm2 (P-value<0.0001), valve circumference from 13+/-0.5 to 7.3+/-0.3 cm (P-value<0.0001), septolateral distance from 2.1+/-0.1 to 1.4+/-0.06 cm (P-value<0.01) and intercommissural distance from 3.4+/-0.1 to 2.7+/-0.03 cm (P-value<0.03). There was significant decrease in the septolateral distance at the level of A2-P2 with respect to other regions. These geometric changes were associated with the improvement in the NYHA class from 3.1+/-0.3 to 1.3+/-0.3 (P-value<0.002).

CONCLUSION

The mitral valve annuloplasty with the Geoform ring restores leaflet coaptation and eliminates mitral regurgitation by effectively modifying the mitral annular geometry.

Mitral insufficiency and morbidity and mortality in left ventricular dysfunction

BACKGROUND

Mitral insufficiency is known to occur in a substantial proportion of patients with heart failure. Its relationship with morbidity and mortality is poorly described.

METHODS

The mortality and hospitalization for heart failure were retrospectively examined in patients who underwent baseline echocardiography in the Studies Of Left Ventricular Dysfunction (SOLVD) treatment and prevention trials. The presence and grade of mitral insufficiency was assessed, and patients with and without mitral insufficiency were compared.

RESULTS

Patients with left ventricular dysfunction and mitral insufficiency had greater than twofold increased risk of death or admission for heart failure over two years (RR 2.38, 95% CI 1.43 to 3.97). This excess risk persisted after adjustment for the severity of heart failure, etiology and differences in treatment (RR 1.82, 95% CI 1.04 to 3.17; P=0.04). The presence of moderate mitral insufficiency versus no insufficiency was associated with even greater independent risk (RR 2.20, 95% CI 1.01 to 4.80; P=0.05). Results were consistent with binary and ordinal analysis of mitral insufficiency.

CONCLUSION

The presence of mitral insufficiency in patients with left ventricular dysfunction is independently associated with adverse outcomes, including death and hospitalization for heart failure. This has potentially important clinical implications for the assessment and management of patients with heart failure.

Changes in Left Ventricular Function and Dimension After Surgical Ventricular Restoration With or Without Concomitant Mitral Valve Procedure

BACKGROUND

An association of mitral regurgitation (MR) with ischemic cardiomyopathy (I-CMP) increases the risk of heart failure and its surgical management remains controversial.

METHODS AND RESULTS

Between July 2001 and June 2006, a total of 49 patients with I-CMP underwent surgical ventricular restoration (SVR) and coronary revascularization with or without concomitant mitral annuloplasty (MAP). The mean age was 59.8 years, and all patients had New York Heart Association (NYHA) class III or IV heart failure (mean left ventricular ejection fraction (LVEF) = 24.8%). Nineteen patients had MR >grade 3 (MR group). SVR and coronary artery bypass grafting were performed in all patients, and concomitant MAP was performed in the MR group. Echocardiography was performed preoperatively, postoperatively, and at mean of 19 months after operation. Preoperative left ventricular (LV) end-diastolic and end-systolic dimensions, left atrial volume index, and MR grade were statistically significantly increased in the MR group. On the early postoperative echocardiogram, mean LVEF was significantly improved, with reduction of LV dimensions, in both groups; however, at follow up, these parameters were more significantly improved in the MR group, but unchanged in non-MR group, reaching almost the same levels as the non-MR group.

CONCLUSION

In patients with I-CMP, MR increases early and late mortality; however, after SVR and concomitant MAP, LV function seems to continuously improve with more significant reduction in the LV dimensions than in the non-MR group.

Mitral valve stiffening in end-stage heart failure: evidence of an organic contribution to functional mitral regurgitation

OBJECTIVE

Mitral regurgitation is a complication for many patients with congestive heart failure. Although this regurgitation is considered purely functional, we hypothesize that the alterations in cardiac geometry and function induce dysfunctional remodeling of the mitral valve, which can be demonstrated by alterations in the material behavior of the leaflets and chordae.

METHODS

Mitral leaflets and chordae from 23 valves from transplant recipient hearts (11 with dilated and 12 with ischemic cardiomyopathy) and from 21 normal valves (from autopsy) were mechanically tested.

RESULTS

Radially oriented anterior mitral leaflet strips from failing hearts were 61% stiffer and 23% less viscous on average than those from autopsy control hearts. The mean stiffness of circumferentially oriented anterior leaflet strips was 50% higher than that of control hearts. Leaflet extensibility was reduced 35% overall. Likewise, the failing heart chordae were an average of 16% stiffer (all P < or = .05).

CONCLUSIONS

Mitral valves in congestive heart failure have significantly altered mechanics that suggest that the tissue is permanently distended and fibrotic and might be unable to stretch sufficiently to cover the valve orifice. These material changes in the valve tissues accompany the biochemical alterations in extracellular matrix composition that we have previously reported. Our finding of leaflet and chordal remodeling suggests that mitral regurgitation in patients experiencing heart failure might not be purely functional and that these mitral valves should not be considered normal. Moreover, there are implications for strategies of mitral valve surgery or percutaneous approaches in this patient population.

Mitral regurgitation in patients with advanced systolic heart failure

BACKGROUND

Mitral regurgitation (MR) may develop in patients with advanced systolic congestive heart failure (CHF) without organic mitral valve disease and contribute to worsening symptoms and survival. Surgical mitral annuloplasty improves symptoms in patients with advanced CHF, and percutaneous approaches to mitral annuloplasty are being developed. Our objective was to define the prevalence, clinical correlates, and prognostic implications of functional MR and the use of mitral annuloplasty in patients with advanced systolic CHF evaluated in a heart failure clinic.

METHODS AND RESULTS

We reviewed clinical, echocardiographic, and survival data from all patients with advanced systolic CHF (New York Heart Association class III or IV; ejection fraction </=35%) resulting from ischemic or idiopathic cardiomyopathy who were evaluated at our heart failure clinic between January 1996 and September 2001. Of 716 patients with advanced CHF, 558 had satisfactory baseline echocardiograms performed at our institution. Among these patients, MR was severe in 24 (4.3%), moderate-severe in 70 (12.5%), moderate in 122 (21.9%), mild-moderate in 66 (11.8%), mild in 218 (39.1%), and absent or present as only a trace in 58 (10.4%). The severity of MR was confirmed by quantitative analysis in 72% of patients with hemodynamically significant MR (more than moderate). The severity of MR correlated with the severity of systolic dysfunction (P <.001), ventricular dilatation (P <.03), atrial dilatation (P <.001), diastolic dysfunction (P <.001), and pulmonary hypertension (P <.001). Coexistent severe or moderate-severe tricuspid regurgitation was present in 25% of patients with hemodynamically significant MR. Patients with hemodynamically significant MR had higher mortality (P=.03) but not when controlling for age, sex, cause, New York Heart Association class, and ejection fraction (P=.95). Only 3 patients subsequently underwent mitral valve repair.

CONCLUSION

Among patients with advanced CHF, hemodynamically significant MR is common. The severity of MR did not provide independent prognostic information in this group recognized to have uniformly high mortality.

Partial left ventriculectomy and mitral valve repair: favorable short-term results in carefully selected patients with advanced heart failure due to dilated cardiomyopathy

BACKGROUND

Because of the scarcity of donor hearts, surgical alternatives to heart transplantation, such as partial left ventriculectomy (PLV), were introduced for treatment of advanced heart failure. Here, we report our experience with this procedure performed in combination with mitral valve repair.

METHODS

Twelve patients with dilated cardiomyopathy (DCM), New York Heart Association (NYHA) class exceeding III on maximal medical therapy, cardiac index of 2.5 liter/min/m2 or less, VO2max of 14 ml/kg/min or less, left ventricular end-diastolic diameter (LVEDD) of 7.0 cm or more, and grade II or greater mitral incompetence, were selected for PLV and mitral valve reconstruction (MVR). Echocardiography, hemodynamics, spiroergometry, and clinical assessment were performed before and 1 year after the operation.

RESULTS

One-year survival was 83.3%. All 10 surviving patients were free from failure of the procedure 1 year post-operatively. From pre-operatively to 1 year post-operatively, NYHA functional class improved from 3.3 +/- 0.3 to 1.9 +/- 0.2 (p < 0.001), cardiac index increased from 2.0 +/- 0.2 liter/min/m2 to 2.9 +/- 0.2 liter/min/m2 (p < 0.001), stroke volume index from 25.9 +/- 4.8 ml/m2 to 40.3 +/- 7.3 ml/m2 (p = 0.008), and VO2max from 10.9 +/- 2.4 ml/kg/min to 16.0 +/- 3.6 ml/kg/min (p = 0.016), whereas LVEDD decreased from 8.4 +/- 0.6 cm to 6.6 +/- 0.3 cm (p < 0.001), left ventricular end-systolic diameter from 6.8 +/- 0.8 cm to 5.3 +/- 0.5 cm (p < 0.001), and mitral incompetence from 2.4 +/- 0.6 to 0.9 +/- 0.6 (p < 0.001). Pulmonary pressures and fractional shortening did not change significantly (p > 0.05). Four patients received an implantable cardioverter/defibrillator as a result of their pathologic electrophysiologic examination.

CONCLUSIONS

In carefully selected patients, PLV combined with MVR achieves short-term results comparable to that after heart transplantation. However, long-term results and multicenter evaluation will be needed to define its place in the treatment of advanced heart failure.

Surgical therapies for heart failure

A variety of invasive procedures have been utilized to reduce the burden on the left ventricle in order to slow or reverse the progressive changes of structural remodeling. These include mitral valve repair, left ventricular assist devices, left ventricular chamber reduction surgery, endovascular patchplasty, dynamic cardiomyoplasty, and a variety of prosthetic implants designed to inhibit remodeling either by constraining chamber enlargement or reducing wall stress to inhibit further growth. Resynchronization therapy also may favorably affect remodeling. The potential of these procedures to slow the progression of heart failure needs to be confirmed in prospective studies.

Advances in heart failure surgery

Heart failure is a major public health problem in the USA and in most Western countries. Nearly 5 million patients in the USA have heart failure with approximately 500,000 patients being diagnosed for the first time each year. Medical therapy is the first-line treatment, and surgery is considered when medical therapy fails or a clear mechanical cause of heart failure is identified and deemed correctable. Current surgical options include coronary revascularization, surgical correction of mitral regurgitation, left ventricular reconstruction, transmyocardial laser revascularization, ventricular assist devices, passive ventricular restraint devices, and cardiac transplantation. While a full discussion of cardiac transplantation is beyond the scope of this article, the other commonly performed procedures will be reviewed.

Apparently normal mitral valves in patients with heart failure demonstrate biochemical and structural derangements

OBJECTIVES

This study assessed apparently normal mitral valves from patients with congestive heart failure (CHF) using biochemical and echocardiographic measures of extracellular matrix (ECM) and anatomy.

BACKGROUND

Mitral regurgitation (MR) is frequently found in patients with CHF. This MR is considered purely functional, yet animal studies suggest that altered left ventricular (LV) function leads to increased cellularity and fibrosis of the mitral valve. Therefore, we hypothesized that patients with CHF might have partly organic MR, via dysfunctional valvular remodeling.

METHODS

Mitral valves from transplant recipient hearts of patients with CHF (23 dilated, 14 ischemic) were analyzed for deoxyribonucleic acid (DNA), collagen, glycosaminoglycan (GAG), and water concentrations and compared with autopsy controls. Cardiac dimensions and functional parameters (measured from recent echocardiograms) were compared with biochemical parameters using a repeated measures generalized linear model.

RESULTS

The mitral valves in CHF had up to 78% more DNA (p <0.03), 59% more GAGs (p <0.02), and 15% more collagen (p <0.007), but 7% less water (p <0.05) than normal. The absence of anterior leaflet redundancy was associated with these deranged biochemical measures (p <0.03). Associations were found between leaflet thickness and DNA concentration (+, p=0.003), annular diameter and chordal collagen (+, p=0.03), and water concentration and both left atrial diameter (-, p=0.008) and LV collagen concentration (-, p=0.04).

CONCLUSIONS

Mitral valves in CHF are biochemically different from normal, with ECM changes that are influenced by the altered cardiac dimensions. This remodeling suggests that MR in patients with CHF may not be purely functional, and that these valves are not "normal."

Feasibility of arresting the process of remodeling

Heart failure (HF) is a massive public health issue. Ventricular remodeling is pivotal to the pathophysiology/progression of HF and an attractive target for intervention. It currently is believed that interdicting the natural history of ventricular remodeling will be crucial to controlling the HF epidemic. This article reviews the current data on the feasibility of arresting this process. This review is not meant to be exhaustive but provides a brief overview of the approaches being contemplated in this field.

Reverse Remodeling of the Failing Ventricle: Surgical Intervention With the Acorn Cardiac Support Device

Preclincial studies have shown that an innovative meshlike cardiac support device (CorCap, Acorn Cardiovascular, Inc., St. Paul, MN) can provide end diastolic support to reduce mechanical stress, improve function, and reverse cardiac remodeling. The CorCap device has been implanted worldwide in more than 130 patients with dilated cardiomyopathy (idiopathic or ischemic), with or without concomitant cardiac surgery. A series of 48 patients was implanted in initial safety and feasibility studies (33 received concomitant cardiac surgery, 15 patients received the CorCap device only). At implant, 33 patients were in New York Heart Association functional class III, 11 in class II, and four in class IV. There were no device-related intraoperative complications, deaths, or adverse events. Eight early and nine late deaths occurred during follow-up extending to 18-24 months. During follow-up, chamber dimensions decreased, and ejection fraction and New York Heart Association functional class improved. The CorCap device is correlated with improvements in patient functional status. Randomized clinical trials are underway in Europe, Australia, and North America.

Catheter-Based Approach to Mitral Regurgitation

Mitral Regurgitation (MR) is a common medical problem. MR is also a prognostic factor; patients with severe symptomatic MR have a poor prognosis with an annual mortality rate of 5% without surgical intervention. An anatomic understanding of the normal and regurgitant mitral valve is essential in order to evaluate appropriately the severity and impact of MR. We briefly discuss mitral complex anatomy, MR evaluation, and treatment options (surgical and catheter-based alternatives) according to the type of lesion found. In particular, our group has shown temporal percutaneous annuloplasty and definitive percutaneous edge-to-edge mitral valve repair to be a feasible technique. Recently a study evaluating endovascular mitral valve edge-to-edge repair was successfully initiated by our group. Acute and chronic ischemic mitral regurgitation and special situations, such as paravalvular leaks, hypertrophic obstructive cardiomyopathy, and mixed lesions are also discussed. Future directions may include the percutaneous transcatheter implantation of a bioprosthetic valve in mitral position.

Surgical Remodeling in Ischemic Cardiomyopathy

Ischemic cardiomyopathy has a very poor prognosis, despite significant advances in pharmacologic therapy in the past decade. Orthotopic heart transplantation is an option for only a small minority of patients. Due to donor shortage and a finite outcome after transplant, nontransplant surgical intervention should be intensively investigated. Coronary artery bypass grafting improves survival in patients with demonstrated myocardial viability. Despite this, patients with the greatest left ventricular volumes do not show an improvement in outcomes. Surgical remodeling results in an improved stress-strain relationship and favorable myocardial remodeling. This may lead to improved survival, improvement in ventricular anatomy, and better quality of life. Surgical remodeling is often combined with revascularization, valve repair, and cardiac resynchronization therapy, along with optimal pharmacologic regimens, to provide a comprehensive therapeutic strategy for patients with this infirmity.

Surgical therapy in advanced heart failure

Congestive heart failure (CHF) affects about 1% of adults in the United States and is a contributing factor in >250,000 deaths per year. In an increasingly elderly population, the surgical treatment of CHF made great progress during the past 3 decades, consuming enormous health care resources. Heart transplantation is still the most effective therapy for end-stage heart disease, with the 10-year survival rate after transplantation approaching 50%. Efforts to increase the supply of donor organs have failed to improve the shortage, underscoring the crucial need for alternatives to cardiac allotransplantation. Alternative surgical options to end-stage heart transplantation are rapidly evolving. Left ventricular assist devices have been used as a bridge to heart transplantation for patients who otherwise might die awaiting a new heart. There is also continued interest in the use of these devices either to bridge patients to full recovery or to destination therapy, without the need for heart replacement. Left ventricular reconstruction, including the Batista and Dor procedures, along with mitral valve repair, cardiomyoplasty, and extreme coronary artery bypass graft surgery, are now being increasingly performed as alternative options. The history, status, and personal experience of surgical treatment of end-stage heart disease are discussed.

New surgical therapies for heart failure

A growing number of patients present with heart failure. Some of them may qualify for surgical correction of their cardiac condition. Since heart transplantation will always be available to only a small number of patients, several new surgical techniques have been developed for approval in heart failure patients. Classic interventions such as revascularization, valve repair, or valve replacement have been improved and modified to meet the need of heart failure patients. Several of these techniques are currently under investigation in large clinical trials. These trials will definitely have an impact on the development of surgical treatment of patients with heart failure.

Papillary muscle sling: a new functional approach to mitral repair in patients with ischemic left ventricular dysfunction and functional mitral regurgitation

BACKGROUND

In patients with ischemic left ventricular dysfunction (LVD) and functional mitral regurgitation (FMR), restoring a more normal alignment between mitral annulus and laterally displaced papillary muscles (PM) may be beneficial in terms of mitral repair and regional dynamics.

METHODS

Ten patients, 29 to 78 years old, with an ejection fraction of 25% to 45%, pulmonary hypertension greater than 60, and New York Heart Association Class III-IV, had their PMs drawn together by a tightly encircling loop using a 4-mm Gore-Tex tube. Associated mitral annuloplasty rings were only moderately undersized. Efficiency was essentially evaluated on reversal of mitral tenting and control of FMR.

RESULTS

Postoperative echocardioraphy revealed changes in "tenting effect" from 14 +/- 2.8 mm to 4 +/- 1.41 mm. Regurgitation is none to trivial in 9 patients, and mild in 1 patient. The posterior left ventricular wall between the PMs is shortened as a result of the surgical remodeling and may be beneficial on local dynamics.

CONCLUSIONS

Joining the PM side-by-side has an obvious immediate effect on mitral leaflet mobility by suppressing the tethering due to displacement of the PM. An eventual result on local ventricular dynamics needs confirmation.

Nontransplant surgical options for congestive heart failure

A wide array of surgical options are currently available for the treatment of congestive heart failure ranging from traditional coronary artery bypass grafting to total artificial heart implantation. The indications for each procedure depend on the severity of disease and the individual patients desires. Some surgical options are indicated for patients with moderate disease and prevent worsening heart failure, whereas other procedures are limited to patients who will only survive with high-risk surgery. Ongoing technologic advances are increasing the number of patients that benefit from the reparative surgical treatment of congestive heart failure.

Hospitalizations for valvular heart disease in chronic dialysis patients in the United States

BACKGROUND

Valvular heart disease has not been studied in a national population of end stage renal disease patients.

METHODS

327,993 dialysis patients in the United States Renal Data System initiated from 1 January 1992 to 30 June 1997 were analyzed in a historical cohort study of patients hospitalized for valvular heart disease (ICD9 Code 424.x, excluding endocarditis, and 394.x-397.x).

RESULTS

2,778 dialysis patients were hospitalized for VHD (incidence rate, 3.57 per 1,000 person years), and dialysis patients had an age-adjusted incidence ratio for valvular heart disease of 5.06 (95% confidence interval, 4.00-6.42) compared to the general population in 1996. In Cox regression analysis, time to hospitalization for valvular heart disease was associated with earlier year of first dialysis, increased age, congestive heart failure and use of erythropoietin prior to dialysis, while African-American race (AHR 0.62, 0.52-0.74) was associated with decreased risk of hospitalization for valvular heart disease. Patients hospitalized for valvular heart disease had increased mortality compared to all other dialysis patients (adjusted hazard ratio by Cox regression 1.35, 95% CI, 1.25-1.46).

CONCLUSIONS

Dialysis patients were at increased risk for hospitalizations for valvular heart disease compared to the general population, which substantially decreased patient survival. The reasons for the decreased risk of African-Americans on chronic dialysis for this complication should be the subject of future trials.

Myosplint implant and shape-change procedure: intra- and peri-operative safety and feasibility

BACKGROUND

In patients with dilated cardiomyopathy (DCM), the heart enlarges, leading to a corresponding increase in ventricular wall stress. To reduce the stress, transventricular tension members (Myosplint, Myocor, Inc.) were implanted to change the left ventricle (LV) effective radius and to reduce the LV wall stress by 20%. We conducted this study to evaluate the intra- and peri-operative safety and feasibility of LV-shape change therapy.

METHODS

In 7 patients, all diagnosed with DCM, Myosplints were implanted. New York Heart Association class ranged from III-IV, and LV end-diastolic diameter ranged from 70 to 102 mm. Mitral valve regurgitation was classified as mild in 3 and moderate in 4 cases. Four patients underwent mitral valve annuloplasty.

RESULTS

We observed no significant device-related complications, such as thromboembolism, bleeding, device instability, or vascular damage, at 90 days. Early indications in a small patient population demonstrate some improvements in clinical parameters.

CONCLUSIONS

From this initial experience, one may conclude that placement of the Myosplint devices can be safely performed without early, significant adverse events. In patients with significant mitral valve incompetence, concomitant mitral valve repair is indicated to realize the full benefit of the procedure. This study also suggests that Myosplints can be safely implanted in combination with mitral valve repair. The long-term effect of each procedure on cardiac function and survival will require further evaluation.

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.

Surgical management of heart failure: an overview

Cardiac transplantation remains the gold standard of surgical therapies for advanced and end-stage heart failure. However, this very limited option trades one disease for another and can benefit only a small minority of patients. Heart failure is currently considered secondary to a structural increase in ventricular chamber volume or remodeling. Surgical therapies formerly contraindicated for the failing heart, as well as new therapies, can successfully affect ventricular remodeling and improve cardiac function. Surgical revascularization for patients with ejection fractions <20% is becoming common. Mitral valve repair is being explored, with surprisingly low operative mortality and encouraging intermediate results. Direct surgical approaches to restoring normal geometry and size to failing hearts, such as left ventricular reduction (Batista procedure), endoventricular patch plasty (Dor procedure), cardiomyoplasty, and prosthetic external constraints are under clinical investigation. Developments in mechanical assist therapy and a new generation of implantable intracorporeal assist devices are also discussed.

Coronary bypass in left heart failure

Clinical experience is accumulating that coronary artery bypass grafting is of great benefit in patients with advanced ischemic cardiomyopathy. At Yale University, we have analyzed short- and long-term results in 188 consecutive patients with an ejection fraction (EF) of 30% or less undergoing coronary artery bypass grafting by a single surgeon. This experience permits the following conclusions: (1) Surgery can be performed safely (mortality 2.8% in elective patients); (2) Major improvement in left ventricular (LV) function is objectively demonstrable (EF change from 23.3% to 33.2%); (3) Symptomatic improvement is noted by patients (NYHA class change from 3.1 to 1.4); and (4) Good long-term survival is realized, relative to expectations with medical management alone (88%, 77%, and 60% at 1, 3, and 5 years). If coronary artery disease is severe and proximally situated and there are adequate target arteries, we do not deny patients surgery based on EF or LV size criteria, nor do we require objective demonstration of reversible ischemia. In fact, hearts in the largest size range (left ventricular end-systolic volume index > 100 mL) actually showed beneficial reverse remodeling subsequent to coronary artery bypass grafting. Surgical revascularization is recommended strongly for patients with advanced ischemic cardiomyopathy. Results rival those of transplantation.

Passive constraint and new shape-change devices for heart failure

Lessons learned from ventricular remodeling procedures have shown that Laplace mechanics, whereby mural tension is related to ventricular diameter, may be beneficially applied to the left ventricle (LV). Recently developed devices, predicated on the Law of Laplace, are directed at interrupting the heart-failure cascade without removing functioning myocardium. The Acorn cardiac support device is a polyester-mesh jacket placed snugly around the heart to provide end-diastolic support and prevent LV dilation. The Myosplint device uses transmural tension members to bisect the dilated LV to create a bilobed LV with decreased mural tension in each cavity. Preclinical and early clinical data with both devices appears promising and may offer a new surgical alternative for patients with worsening heart failure.