Surgical ventricular restoration in the treatment of congestive heart failure due to post-infarction ventricular dilation

Cardiac tissue engineering: renewing the arsenal for the battle against heart disease

The development of therapies that lead to the regeneration or functional repair of compromised cardiac tissue is the most important challenge facing translational cardiovascular research today.

Surgical options for the management of ischemic cardiomyopathy

OPINION STATEMENT

Novel surgical alternatives and the refinement of conventional surgical therapies for the treatment of ischemic cardiomyopathy are in constant evolution. Current approaches involve the determined application of the appropriateness criteria for CABG surgery, the extension of mitral valve repair to complex patients with ischemic cardiomyopathy, finding appropriate patients who might benefit from surgical ventricular reconstruction, and surgical attempts to regenerate lost or damaged myocardium with transplanted stem cells. The refinement of surgical techniques and the medical optimization of candidates for surgery remain a cornerstone of management for patients with complex heart disease like ischemic cardiomyopathy. The horizon is bright for patients suffering from this condition and concentrated research efforts by groups such as the NHLBI-sponsored Cardiothoracic Surgery Network will have a major impact on the future of patients with heart disease.

Coronary artery bypass grafting in patients with left ventricular dysfunction: predictors of long-term survival and impact of surgical strategies

BACKGROUND

In the surgical management of ischemic cardiomyopathy, factors associated with long-term prognosis after coronary artery bypass grafting (CABG) in patients with severe left ventricular (LV) dysfunction are poorly understood. This study aimed to determine predictors of clinical outcomes in patients with severe LV dysfunction undergoing CABG.

METHODS

Out of 6084 patients who underwent CABG between 1997 and 2011, 476 patients (aged 62.6 ± 9.3 years, 100 females) were identified as having severe LV dysfunction (ejection fraction ≤ 35%), preoperatively. All-cause mortality and adverse cardiac events (myocardial infarction, repeat revascularization, stroke and hospitalization due to cardiovascular causes) were evaluated during a median follow-up period of 55.2 months (inter-quartile range: 26.4-94.8 months).

RESULTS

During the follow-up, 187 patients (39.3%) died and 126 cardiac events occurred in 104 patients (21.8%). Five-year survival and event-free survival rates were 72.1 ± 2.2% and 61.3 ± 2.4%, respectively. On Cox-regression analysis, old age (P < 0.001), recent MI (P < 0.001), history of coronary stenting (P = 0.023), decreased glomerular filtration rate (P < 0.001), and presence of mitral regurgitation (≥moderate) (P = 0.012) or LV wall thinning (P = 0.007) emerged as significant and independent predictors of death. After adjustment for important covariates affecting outcomes, none of the pump strategy (off-pump vs. on-pump), concomitant mitral surgery or surgical ventricular reconstruction (SVR) affected survival or event-free survival (P = 0.082 to >0.99).

CONCLUSIONS

Long-term survival following CABG in patients with severe LV dysfunction was affected by age, renal function, recent MI, prior coronary stenting, and presence of mitral regurgitation or LV wall thinning. Neither concomitant mitral surgery nor SVR, however, had significant influence on clinical outcomes.

Analysis of patient-specific surgical ventricular restoration: importance of an ellipsoidal left ventricular geometry for diastolic and systolic function

Surgical ventricular restoration (SVR) is a procedure designed to treat heart failure by surgically excluding infarcted tissues from the dilated failing left ventricle. To elucidate and predict the effects of geometrical changes from SVR on cardiac function, we created patient-specific mathematical (finite-element) left ventricular models before and after surgery using untagged magnetic resonance images. Our results predict that the postsurgical improvement in systolic function was compromised by a decrease in diastolic distensibility in patients. These two conflicting effects typically manifested as a more depressed Starling relationship (stroke volume vs. end-diastolic pressure) after surgery. By simulating a restoration of the left ventricle back to its measured baseline sphericity, we show that both diastolic and systolic function improved. This result confirms that the increase in left ventricular sphericity commonly observed after SVR (endoventricular circular patch plasty) has a negative impact and contributes partly to the depressed Starling relationship. On the other hand, peak myofiber stress was reduced substantially (by 50%) after SVR, and the resultant left ventricular myofiber stress distribution became more uniform. This significant reduction in myofiber stress after SVR may help reduce adverse remodeling of the left ventricle. These results are consistent with the speculation proposed in the Surgical Treatment for Ischemic Heart Failure trial (20) for the neutral outcome, that "the lack of benefit seen with surgical ventricular reconstruction is that benefits anticipated from surgical reduction of left ventricular volume (reduced wall stress and improvement in systolic function) are counter-balanced by a reduction in diastolic distensibility."

LEFT VENTRICULAR REMODELLING AND MITRAL VALVE REMODELLING IN CORONARY HEART DISEASE PATIENTS WITH POST-SURGERY PROGRESSION OF MITRAL REGURGITATION

The progression of ischemic mitral regurgitation (MR) after coronary arty bypass graft (CABG) surgery remains one of the most complex and still unresolved problems in the treatment of coronary heart disease (CHD).

Aim. To study myocardial function, left ventricular (LV) remodelling, and mitral valve (MV) remodelling in CHD patients with MR progression after isolated CABG or CABG combined with LV reconstructive surgery.

Material and methods. In total, 101 CHD patients after CABG were included in the analysis.

Results. The mechanisms of MR progression after isolated CABG differ from those after CABG and LV reconstructive surgery. After the former, LV remodelling progresses both locally and globally, while after the latter, the LV remodelling progression is predominantly global. The patients with post-surgery MR progression differ from their peers without MR in terms of all key parameters of MV geometry.

Conclusion. The leading mechanism of MR progression is local and global LV remodelling, which leads to papillary muscle dislocation and MV leaflet tension and restricted motion. The categories of patients with a high risk of post-surgery MR progression are defined. 

Medical management is the way to go for ventricular reconstruction post STICH?

Ventricular remodeling is a complex process mediated by pathogenic factors all of which interact at the cellular, ventricular and systemic levels to cause progressive left ventricular dilation and subsequently a heart failure syndrome. Remodeling is a well-characterized response to insult or injury and is initiated early on by neurohormonal activation. Neurohormonal antagonists have formed the foundation of therapy to alter the progression of remodeling and concomitantly improve outcomes. Surgical ventricular reconstruction was designed as a surgical means to reduce the ventricular radius and in principal decrease ventricular wall stress as defined by the Law of Laplace. Despite optimistic initial results from case series, the Surgical Treatment for Ischemic Heart Failure Trial (STICH) trial, a large randomized trial of ventricular reconstruction in addition to coronary artery bypass surgery (CABG) therapy for management of patients with heart failure with a reduced ejection fraction showed no clinical benefit. We will summarize the evidence that demonstrates the foundational role of neurohormonal blockade in improving outcomes in patients with heart failure with a reduced ejection and the evidence behind its role in "medical ventricular reconstruction".

Surgical ventricular restoration for the treatment of heart failure

Heart failure (HF) is an emerging epidemic affecting 15 million people in the USA and Europe. HF-related mortality was unchanged between 1995 and 2009, despite a decrease in the incidence of cardiovascular disease. Conventional explanations include an aging population and improved treatment of acute myocardial infarction and HF. An adverse relationship between structure and function is the central theme in patients with systolic dysfunction. The normal elliptical ventricular shape becomes spherical in ischemic, valvular, and nonischemic dilated cardiomyopathy. Therapeutic decisions should be made on the basis of ventricular volume rather than ejection fraction. When left ventricular end-systolic volume index exceeds 60 ml/m², medical therapy, CABG surgery, and mitral repair have limited benefit. This form-function relationship can be corrected by surgical ventricular restoration (SVR), which returns the ventricle to a normal volume and shape. Consistent early and late benefits in the treatment of ischemic dilated cardiomyopathy with SVR have been reported in >5,000 patients from various international centers. The prospective, randomized STICH trial did not confirm these findings and the reasons for this discrepancy are examined in detail. Future surgical options for SVR in nonischemic and valvular dilated cardiomyopathy, and its integration with left ventricular assist devices and cell therapy, are described.

The future of heart transplantation

The field of heart transplantation has seen significant progress in the past 40 years. However, the breakthroughs in long-term outcome have seen stagnation in the past decade. Through advances in genomics and transcriptomics, there is hope that an era of personalized transplant therapy lies in the future. To see where heart transplantation truly fits into the long term, searching for and understanding the alternative approaches for heart failure therapy is both important and inevitable. The application of mechanical circulatory support has contributed to the largest advancement in treatment of end stage heart failure. It has already been approved for destination therapy of heart failure, and greater portability and ease of use of the device will be the future trend. Although it is still not prime time for stem cell therapy, clinical experiences have already suggested its potential therapeutic effects. And finally, whole organ engineering is on the horizon as new techniques have opened the way for this to proceed. In the end, progress on alternative therapies largely depends on our deeper understanding of the mechanisms of heart failure and how to prevent it.

Insights from the STICH trial: change in left ventricular size after coronary artery bypass grafting with and without surgical ventricular reconstruction

OBJECTIVE

The present analysis of the Surgical Treatment for Ischemic Heart Failure randomized trial data examined the left ventricular volumes at baseline and 4 months after surgery to determine whether any magnitude of postoperative reduction in end-systolic volume affected survival after coronary artery bypass grafting alone compared with bypass grafting plus surgical ventricular reconstruction.

METHODS

Of the 1000 patients randomized, 555 underwent an operation and had a paired imaging assessment with the same modality at baseline and 4 months postoperatively. Of the remaining 455 patients, 424 either died before the 4-month study or did not have paired imaging tests and were excluded, and 21 were not considered because they had died before surgery or did not receive surgery.

RESULTS

Surgical ventricular reconstruction resulted in improved survival compared with coronary artery bypass grafting alone when the postoperative end-systolic volume index was 70 mL/m(2) or less. However, the opposite was true for patients achieving a postoperative volume index greater than 70 mL/m(2). A reduction in the end-systolic volume index of 30% or more compared with baseline was an infrequent event in both treatment groups and did not produce a statistically significant survival benefit with ventricular reconstruction.

CONCLUSIONS

In patients undergoing coronary artery bypass grafting plus surgical ventricular reconstruction, a survival benefit was realized compared with bypass alone, with the achievement of a postoperative end-systolic volume index of 70 mL/m(2) or less. Extensive ventricular remodeling at baseline might limit the ability of ventricular reconstruction to achieve a sufficient reduction in volume and clinical benefit.

Treatment options in end-stage heart failure: where to go from here?

Chronic heart failure is a major healthcare problem associated with high morbidity and mortality. Despite significant progress in treatment strategies, the prognosis of heart failure patients remains poor. The golden standard treatment for heart failure is heart transplantation after failure of medical therapy, surgery and/or cardiac resynchronisation therapy. In order to improve patients’ outcome and quality of life, new emerging treatment modalities are currently being investigated, including mechanical cardiac support devices, of which the left ventricular assist device is the most promising treatment option. Structured care for heart failure patients according to the most recent international heart failure guidelines may further contribute to optimal decision-making. This article will review the conventional and novel treatment modalities of heart failure.

CMR imaging assessing viability in patients with chronic ventricular dysfunction due to coronary artery disease: a meta-analysis of prospective trials

OBJECTIVES

The purpose of this study was to compare the diagnostic accuracy of cardiac magnetic resonance (CMR) assessing myocardial viability in patients with chronic left ventricular (LV) dysfunction due to coronary artery disease using 3 techniques: 1) end-diastolic wall thickness (EDWT); 2) low-dose dobutamine (LDD); and 3) contrast delayed enhancement (DE).

BACKGROUND

CMR has been proposed to assess myocardial viability over the past decade. However, the best CMR strategy to evaluate patients being contemplated for revascularization has not yet been determined. Some centers advocate DE CMR due to its high sensitivity to identify scar, whereas others favor the use of LDD CMR for its ability to identify contractile reserve.

METHODS

A systematic review of MEDLINE, Cochrane, and Embase for all the prospective trials assessing myocardial viability in subjects with chronic LV dysfunction using CMR was performed using a standard approach for meta-analysis for diagnostic tests and a bivariate analysis of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

A total of 24 studies of CMR evaluating myocardial viability with 698 patients fulfilled the inclusion criteria. Eleven studies used DE, 9 studies used LDD, and 4 studies used EDWT. Our meta-analysis indicates that among CMR methods, DE CMR provides the highest sensitivity as well as the highest NPV (95% and 90%, respectively) for predicting improved segmental LV contractile function after revascularization, followed by EDWT CMR, whereas LDD CMR demonstrated the lowest sensitivity/NPV among all modalities. On the other hand, LDD CMR offered the highest specificity and PPV (91% and 93%, respectively), followed by DE CMR, whereas EDWT showed the lowest of these parameters.

CONCLUSIONS

DE CMR provides the highest sensitivity and NPV, whereas LDD CMR provides the best specificity and PPV. In light of these findings, integrating these 2 methods should provide increased accuracy in evaluating patients with chronic LV dysfunction being considered for revascularization.

Myoblast sheet can prevent the impairment of cardiac diastolic function and late remodeling after left ventricular restoration in ischemic cardiomyopathy

BACKGROUND

Impairment of diastolic function and late remodeling are concerns after left ventricular restoration (LVR) for ischemic cardiomyopathy. This study aims to evaluate the effects of combined surgery of myoblast sheets (MS) implantation and LVR.

METHODS

Rat myocardial infarction model was established 2 weeks after left anterior descending artery ligation. They were divided into three groups: sham operation (n=15; group sham), LVR by plicating the infracted area (n=15; group LVR), and MS implantation with LVR (n=15; group LVR+MS).

RESULTS

Serial echocardiographic study revealed significant LV redilatation and decrease of ejection fraction 4 weeks after LVR in group LVR. MS implantation combined with LVR prevented those later deteriorations of LV function in group LVR+MS. Four weeks after the operation, a hemodynamic assessment using a pressure-volume loop showed significantly preserved diastolic function in group LVR+MS; end-diastolic pressure (LVR vs. LVR+MS: 9.0±6.6 mm Hg vs. 2.0±1.0 mm Hg, P<0.05), end-diastolic pressure-volume relationship (LVR vs. LVR+MS 42±23 vs. 13±6, P<0.05). Histological examination revealed cellular hypertrophy and LV fibrosis were significantly less and vascular density was significantly higher in group LVR+MS than in the other two groups. Reverse transcription polymerase chain reaction demonstrated significantly suppressed expression of transforming growth factor-beta, Smad2, and reversion-inducing cysteine-rich protein with Kazal motifs in group LVR+MS.

CONCLUSIONS

MS implantation decreased cardiac fibrosis by suppressing the profibrotic gene expression and attenuated the impairment of diastolic function and the late remodeling after LVR. It is suggesting that MS implantation may improve long-term outcome of LVR for ischemic heart disease.

Repair of left ventricular aneurysm with acellular dermis graft: A case report

We report the use of a novel graft material in cardiac surgery, acellular human dermis graft, to repair a left ventricular aneurysm in a patient undergoing surgical ventricular restoration. We also describe the postoperative magnetic resonance imaging characteristics of the dermis graft. We conclude that acellular dermis graft has material handling properties that allow it to be used in left ventricular aneurysm repair. On magnetic resonance imaging, there is no gadolinium enhancement of the graft and the graft is akinetic.

Management of mitral regurgitation during left ventricular reconstruction for ischemic heart failure

OBJECTIVE

Remodeling of the left ventricle (LV) in ischemic cardiomyopathy frequently leads to functional mitral regurgitation (MR). The indication for correcting MR in patients undergoing LV reconstruction (LVR) is unclear. In this study, we evaluated our strategy of correcting MR≥grade 2+ by restrictive mitral annuloplasty (RMA) during LVR.

METHODS

We studied 92 consecutive patients (76 men, mean age 61±10 years) who underwent LVR for ischemic heart failure (IHF). RMA was performed in all patients with MR≥grade 2+ on preoperative echocardiography and in patients who showed increased MR to ≥grade 2+ immediately after LVR. Patients were attributed to a RMA and no-RMA group, depending on whether or not concomitant RMA had been performed. Mean clinical and structured echocardiographic follow-up was 47±20 months and was 100% complete.

RESULTS

In 38 out of 40 patients (95%) with preoperative MR≥grade 2+, concomitant RMA was planned and performed. In 17 out of 52 patients (33%) with MR<grade 2+ preoperatively, MR increased after LVR to ≥grade 2+ leading to additional RMA during a second period of aortic cross-clamping. Early mortality in the RMA group (n=55) was 12.7% and survival at 36 months 78.2±11.2%. Early mortality in the no-RMA group (n=37) was 5.4% and survival at 36 months 81.1±12.8%. Patients in the RMA group had significantly more reduced LV function with greater LV dimensions and volumes preoperatively. Echocardiography demonstrated sustained improvement in LVEF with reduction of LV volumes in both patient groups. Recurrence of MR at late follow-up was observed in 2 patients (1 patient per group).

CONCLUSIONS

Patients with IHF eligible for LV reconstruction have MR≥grade 2+ in 44% of cases. In one-third of IHF patients with MR<grade 2+ preoperatively, MR increases to ≥grade 2+ after LVR. Concomitant mitral valve repair for MR≥grade 2+, on either preoperative echocardiography or immediately after LVR, results in favorable late clinical and echocardiographic outcome that proved to be similar to patients without concomitant mitral valve repair, despite more advanced disease.

Percutaneous left ventricular partitioning in patients with chronic heart failure and a prior anterior myocardial infarction: Results of the PercutAneous Ventricular RestorAtion in Chronic Heart failUre PaTiEnts Trial

OBJECTIVES

The aim of this study was to assess the feasibility, safety, and preliminary efficacy of a novel percutaneous left ventricular partitioning device (VPD) in patients with chronic heart failure (HF) and a prior anterior myocardial infarction.

BACKGROUND

Anterior myocardial infarction is frequently followed by left ventricular remodeling, HF, and increased long-term morbidity and mortality.

METHODS

Thirty-nine patients were enrolled in a multinational, nonrandomized, longitudinal investigation. The primary end point was an assessment of safety, defined as the successful delivery and deployment of the VPD and absence of device-related major adverse cardiac events over 6 months. Secondary (exploratory) efficacy end points included changes in hemodynamics and functional status and were assessed serially throughout the study.

RESULTS

Ventricular partitioning device placement was not attempted in 5 (13%) of 39 subjects. The device was safely and successfully implanted in 31 (91%) of the remaining 34 patients or 79% of all enrolled patients. The 6-month rate of device-related major adverse cardiac event occurred in 5 (13%) of 39 enrolled subjects and 5 (15%) of 34 treated subjects, with 1 additional event occurring between 6 and 12 months. For patients discharged with the device to 12 months (n = 28), New York Heart Association class (2.5 ± 0.6 to 1.3 ± 0.6, P < .001) and quality-of-life scores (38.6 ± 6.1 to 28.4 ± 4.4, P < .002) improved significantly; however, the 6-minute hall walk distance (358.5 ± 20.4 m to 374.7 ± 25.6 m, P nonsignificant) only trended toward improvement.

CONCLUSIONS

The left VPD appears to be relatively safe and potentially effective in the treatment for patients with HF and a prior anterior myocardial infarction. However, these limited results suggest the need for further evaluation in a larger randomized controlled trial.

The renewed concept of the Batista operation for ischemic cardiomyopathy: maximum ventricular reduction

OBJECTIVES

The reconstruction of the left ventricle (LV) is effective in the treatment of ischemic cardiomyopathy with large akinetic or dyskinetic areas. However, late survival outcomes are related to the remnant left ventricular cavity size, thus eliminating intracavitary patch placement provides additional LV reduction. The aim of this study was to analyze the results with left ventricular reconstruction surgery using the concept of maximum ventricular reduction, with systematic patch abolition.

METHODS

Seventy-six consecutive patients with ischemic heart disease (age 30-78 years, mean 57.6 ± 10.1), evolving in functional class III and IV underwent surgical ventricular reconstruction with no use of intracavitary patches or Teflon strips for closing the left ventriculotomy.

RESULTS

The left ventricular end-systolic diameter decreased from 52.3 ± 5.4 in the preoperative period to 45.2 ± 6.9 mm in the postoperative period. LV ejection fraction increased from 34.2% ± 10.4% to 45.5% ± 9.4%. Associated CABG was performed in 75/76 patients with a mean of 2.4 grafts per patient. The 30-day mortality was 3/76 (3.9%). At an average follow up of 39 months, the majority of the patients (91.4%) remain in functional class I and II.

CONCLUSION

The concept of maximizing LV reduction with systematic patchless reconstruction is feasible, safe and effective, the early and late outcomes comparing favorably to previous series reported in the medical literature. Additionally, the concept meets the contemporary pathophysiologic basis of heart failure.

Dilated phase of hypertrophic cardiomyopathy caused by two different sarcomere mutations, treated with surgical left ventricular reconstruction and cardiac resynchronization therapy with a defibrillator

We herein report the case of a 61-year-old woman with dilated phase of hypertrophic cardiomyopathy (D-HCM) who had been diagnosed with HCM 17 years previously. On admission, her left ventricle (LV) had marked dilation, dyssynchrony with diffuse severe hypokinesis, and ventricular tachycardia. She had two mutations in the cardiac myosin binding protein-C gene, which were suspected to be the causes of the D-HCM. We performed LV reconstruction surgery and cardiac resynchronization therapy with a defibrillator for her drug-resistant severe heart failure. After surgery, her New York Heart Association class dramatically improved, and she has not been re-hospitalized since these treatments.

Reverse remodeling in heart failure--mechanisms and therapeutic opportunities

Heart failure (HF) involves changes in cardiac structure, myocardial composition, myocyte deformation, and multiple biochemical and molecular alterations that impact heart function and reserve capacity. Collectively, these changes have been referred to as 'cardiac remodeling'. Understanding the components of this process with the goal of stopping or reversing its progression has become a major objective. This concept is often termed 'reverse remodeling', and is successfully achieved by inhibitors of the renin-angiotensin-aldosterone system, β-blockers, and device therapies such as cardiac resynchronization or ventricular assist devices. Not every method of reverse remodeling has long-lasting clinical efficacy. However, thus far, every successful clinical treatment with long-term benefits on the morbidity and mortality of patients with HF reverses remodeling. Reverse remodeling is defined by lower chamber volumes (particularly end-systolic volume) and is often accompanied by improved β-adrenergic and heart-rate responsiveness. At the cellular level, reverse remodeling impacts on myocyte size, function, excitation-contraction coupling, bioenergetics, and a host of molecular pathways that regulate contraction, cell survival, mitochondrial function, oxidative stress, and other features. Here, we review the current evidence for reverse remodeling by existing therapies, and discuss novel approaches that are rapidly moving from preclinical to clinical trials.

Cardiac regeneration therapy: connections to cardiac physiology

Without heart transplantation, a large number of patients with failing hearts worldwide face poor outcomes. By means of cardiomyocyte regeneration, cardiac regeneration therapy is emerging with great promise as a means for restoring loss of cardiac function. However, the limited success of clinical trials using bone marrow-derived cells and myoblasts with heterogeneous constituents, transplanted at a wide range of cell doses, has led to disagreement on the efficacy of cell therapy. It is therefore essential to reevaluate the evidence for the efficacy of cell-based cardiac regeneration therapy, focusing on targets, materials, and methodologies. Meanwhile, the revolutionary innovation of cardiac regeneration therapy is sorely needed to help the millions of people who suffer heart failure from acquired loss of cardiomyocytes. Cardiac regeneration has been used only in limited species or as a developing process in the rodent heart; now, the possibility of cardiomyocyte turnover in the human heart is being revisited. In the pursuit of this concept, the use of cardiac stem/progenitor stem cells in the cardiac niche must be focused to usher in a second era of cardiac regeneration therapy for the severely injured heart. In addition, tissue engineering and cellular reprogramming will advance the next era of treatment that will enable current cell-based therapy to progress to "real" cardiac regeneration therapy. Although many barriers remain, the prevention of refractory heart failure through cardiac regeneration is now becoming a realistic possibility.

Myocardial regeneration in heart failure: integrated development of biological therapeutic approaches

Heart failure currently constitutes one of the greatest health problems in the Western world. Its incidence, far from diminishing or even remaining stable, is actually still increasing in association with the aging of the population and its lifestyle. A better knowledge of physiopathological mechanisms has allowed for the development of new therapeutic focal points and lines of research. Nevertheless, its treatment is complex and encompasses a multidisciplinary approach. Patients in an advanced stage still have a very high mortality rate in spite of receiving optimum medical care. The development of new therapeutic techniques that afford a better prognosis has therefore been essential. Of these, and leaving aside surgical treatments, myocardial regeneration by means of cellular therapy, new concepts in tissue engineering and their results, and the applications of new advances in the field of immunomodulation have all recently experienced development. In this article, the aim is to bring the latest concepts in the physiopathology and humoral response of cardiac failure up to date as well as doing the same with the therapeutic approaches in this area.

Surgical ventricular restoration to reverse left ventricular remodeling

Heart failure is one of the major health care issues in the Western world. An increasing number of patients are affected, leading to a high rate of hospitalization and high costs. Even with administration of the best available medical treatment, mortality remains high. The increase in left ventricular volume after a myocardial infarction is a component of the remodeling process. Surgical Ventricular Restoration (SVR) has been introduced as an optional therapeutic strategy to reduce left ventricular volume and restore heart geometry. So far, it has been established that SVR improves cardiac function, clinical status, and survival in patients with ischemic, dilated cardiomyopathy and heart failure. Since its first description , SVR has been refined in an effort to standardize the procedure and to optimize the results. This review will discuss the rationale behind surgical reversal of LV remodeling, the SVR technique, its impact on cardiac function and survival, and future expectations.

Computational finite element model of cardiac torsion

PURPOSE

A novel finite-element model of ventricular torsion for the analysis of the twisting behavior of the left human ventricle was developed, in order to investigate the influence of various biomechanical parameters on cardiac kinematics.

METHODS

The ventricle was simulated as a thick-walled ellipsoid composed of nine concentric layers. Arrays of reinforcement bars were embedded in each layer to mimic physiological myocardial anisotropy. The reinforcement bars were activated through an artificial combination of thermal and mechanical effects in order to obtain a contractile behavior which is similar to that of myocardial fibers. The presence of an incompressible fluid inside the ventricular cavity was also simulated and the ventricle was combined with simple lumped-parameter hydraulic circuits reproducing preload and afterload. Changes to a number of cardiac parameters, such as preload, afterload and fiber angle orientation were introduced, in order to study the effects of these changes on cardiac torsion.

RESULTS

The model is able to reproduce a similar torsional behavior to that of a physiological heart. The results of the simulations showed that there was sound correspondence between the model outcomes and available data from the literature. Results confirmed the importance of symmetric transmural patterns for fiber orientation.

CONCLUSIONS

This model represents an important step on the path towards unveiling the complexity of cardiac torsion. It proves to be a practical and versatile tool which could assist clinicians and researchers by providing them with easily-accessible, detailed data on cardiac kinematics for future diagnostic and surgical purposes.

Low-risk profile for malignant ventricular arrhythmias and sudden cardiac death after surgical ventricular reconstruction

BACKGROUND

Although it has been recently demonstrated that there was no significant difference in total survival and clinical outcomes between patients who underwent coronary artery bypass grafting (CABG) with or without surgical ventricular reconstruction (SVR), the question of whether or not SVR decreases the arrhythmic risk profile in this population has not been clarified yet.

OBJECTIVE

To determine the real incidence of sudden cardiac death (SCD) and sustained ventricular tachycardia/ventricular fibrillation (sustained VT/VF) in patients following CABG added to SVR and to define their clinical and echocardiographic parameters predicting in-hospital and long-term arrhythmic events (SCD + sustained VT/VF).

METHODS

Pre- and postoperative clinical and echocardiographic values as well as postoperative electrocardiogram Holter data of 65 patients (21 female, 63 ± 11 years) who underwent SVR + CABG were retrospectively evaluated.

RESULTS

 Mean follow-up was 1,105 ± 940 days. At 3 years, the SCD-free rate was 98% and the rate free from arrhythmic events was 88%. Multivariate logistic analysis identified a preoperative left ventricular end-systolic volume index (LVESVI) > 102 mL/m(2) (odds ratio [OR] 1.4, confidence interval [CI] 1.073-1.864, P = 0.02; sensitivity 100%, specificity 94%) and a postoperative pulmonary artery systolic pressure (PASP) > 27 mmHg (OR 2.3, CI 1.887-4.487, P = 0.01; sensitivity 100%, specificity 71%) as independent predictors of arrhythmic events.

CONCLUSIONS

Our and previous studies report a low incidence of arrhythmic events in patients following SVR added to CABG, considering the high-risk profile of the study population. A preoperative LVESVI > 102 mL/m(2) and a postoperative PASP > 27 mmHg had a good sensitivity and specificity in predicting arrhythmic events.

The impact of volume reduction on early and long-term outcomes in surgical ventricular restoration for severe heart failure

BACKGROUND

Recent published results suggest no additive benefit to surgical ventricular restoration (SVR) when combined with coronary artery bypass grafting. However, there may still be a subgroup of patients with severe heart failure who can benefit from this procedure. We reviewed our institutional experience with SVR to determine early and late outcomes based on volume reduction.

METHODS

We retrospectively reviewed our SVR patients (January 2002 to April 2008) with follow-up to March 2009. Baseline comorbidities, operative data, and postoperative outcomes were assessed by chart review, phone calls, and mailings. Survival was modeled using the Kaplan-Meier method. Cardiac magnetic resonance imaging, myocardial perfusion scans, and echocardiography assessed cardiac function, candidacy for SVR, and volume reduction.

RESULTS

We reviewed 87 consecutive SVR patients (69 men). Mean age at operation was 61.1 years. Preoperatively, all patients had congestive heart failure, with 80 (92%) at New York Heart Association III/IV. All patients underwent preoperative viability studies. Three-vessel occlusion exceeding 50% was present in 69 (79%). After SVR, ejection fraction improved from 0.236 to 0.332 (p<0.001). Preoperative and postoperative magnetic resonance imaging in 26 patients (30.0%) showed a 30.8% reduction in left ventricular end systolic volume index. At follow-up, 51 of 66 (77%) improved to New York Heart Association I/II. One intraoperative death occurred. Preoperative left ventricular end systolic volume index of 80 to 120 was associated with improved survival (73% at 3 years).

CONCLUSIONS

SVR is a surgical option for appropriately selected patients with severe congestive heart failure. In these high-risk patients, SVR successfully increased ejection fraction and decreased symptoms. A left ventricular end systolic volume index of 80 to 120 may be the ideal range for SVR procedures.