Coronary bypass in left heart failure

Cardiac remodelling - Part 2: Clinical, imaging and laboratory findings. A review from the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology

In patients with heart failure, the beneficial effects of drug and device therapies counteract to some extent ongoing cardiac damage. According to the net balance between these two factors, cardiac geometry and function may improve (reverse remodelling, RR) and even completely normalize (remission), or vice versa progressively deteriorate (adverse remodelling, AR). RR or remission predict a better prognosis, while AR has been associated with worsening clinical status and outcomes. The remodelling process ultimately involves all cardiac chambers, but has been traditionally evaluated in terms of left ventricular volumes and ejection fraction. This is the second part of a review paper by the Study Group on Biomarkers of the Heart Failure Association of the European Society of Cardiology dedicated to ventricular remodelling. This document examines the proposed criteria to diagnose RR and AR, their prevalence and prognostic value, and the variables predicting remodelling in patients managed according to current guidelines. Much attention will be devoted to RR in patients with heart failure with reduced ejection fraction because most studies on cardiac remodelling focused on this setting.

Coronary bypass in left ventricular dysfunction and differential cardiac recovery

Background

We aimed to examine the efficacy of surgical revascularization with respect to improvement in ventricular function and survival in patients with ischemic cardiomyopathy and poor left ventricular function.

Methods

We retrospectively analyzed the data of 429 patients (median age 64.6 years, 81.1% male) with ejection fractions <40% undergoing isolated primary coronary artery bypass grafting from 2000 to 2016. Techniques included on-pump cardioplegic arrest ( n = 312), off-pump ( n = 75), and on-pump beating heart ( n = 42). Propensity matching was performed to compare the cardioplegic arrest group ( n = 114) with the combined off-pump and beating heart groups ( n = 114).

Results

Postoperatively, ejection fraction increased by 10.1% ± 13.1% (from 31.4% ± 7.1% to 41.6% ± 13.6%; p < 0.001) and mitral regurgitation grade improved ( p < 0.001) but right ventricular function on echocardiographic assessment worsened over time ( p = 0.04). No difference in ejection fraction improvement was seen in the time periods <1 (9.8% ± 11.2%), 1–5 (11.6% ± 14.5%), and >5 (8.8% ± 14.2%) years ( p = 0.442). Following propensity matching, there was no significant difference between the combined off-pump/beating heart and cardioplegic arrest groups with respect to survival or postoperative complications.

Conclusions

Patients with moderate to severe left ventricular dysfunction experience long-term improvement in left ventricular ejection fraction after coronary artery bypass. However, right ventricular function often continues to decline, contributing to persistent or worsening heart failure symptoms and late mortality. No difference in survival was seen between the 2 techniques.

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.

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: an operation to reverse remodeling - the basic science (part I)

Congestive heart failure as a consequence of ischemic heart disease is an increasing medical problem. Notwithstanding the huge advances in the medical and conventional surgical management of heart failure, eventual outcomes remain suboptimal. This 2 part article outlines the magnitude of the problem, the limitations of conventional therapies as they exist, and the use of newer procedures that directly address the restoration of ventricular pump function.

The first part of the article deals with the pathology of different facets of the remodeling process, and the unique anatomy, geometry and flow dynamics as they pertain to ventricular function in the normal as well as the failing heart. It then details the limitations of conventional therapy, thereby laying the basis for the need and evolution of newer surgical procedures and ends with the selection of patients for ventricular restoration procedures and the pitfalls in the choice of patients for such newer techniques.

Early results with cardiac support device implant in patients with ischemic and non‐ischemic cardiomyopathy

OBJECTIVE

To evaluate the possible beneficial echocardiographic, functional and quality of life improving effects of passive containment surgery using the CorCap Cardiac Support Device in heart failure patients with dilated cardiomyopathy.

DESIGN

Eight patients with dilated cardiomyopathy subjected to cardiac surgery received the Cardiac Support Device. Patients with ischemic cardiomyopathy (n = 4) underwent coronary artery bypass surgery receiving one to three bypass grafts. In the idiopathic cardiomyopathy group (n = 4) mitral valve plasty was performed in two patients while two patients received the Cardiac Support Device only.

RESULTS

All patients survived the surgery and were discharged to home. There was a gradual, sustained improvement in cardiac dimensions (left ventricular end-diastolic diameter, left ventricular end-systolic diameter) and functional improvement (ejection fraction, 6-min walk, NYHA functional class) as well as quality of life. These beneficial effects developed more rapidly and more extensively in the idiopathic cardiomyopathy group.

CONCLUSION

Addition of the Cardiac Support Device to conventional cardiac surgery, or applied alone, is safe and simple. The device seems to reverse ventricular dilatation and improve functional capacity and well-being of heart failure patients with dilated cardiomyopathy. Further studies will delineate what patient population will best benefit from passive containment surgery using the CorCap Cardiac Support Device.

Early and mid-term impacts of cardiopulmonary bypass on coronary artery bypass grafting in patients with poor left ventricular dysfunction: a propensity score analysis

BACKGROUND

Cardiopulmonary bypass may exacerbate myocardial damage in compromised left ventricles. Early and mid-term outcomes of off-pump coronary artery bypass grafting (OPCAB) vs on-pump coronary artery bypass grafting (On-pump CABG) were compared in patients with poor left ventricular dysfunction, using an analysis of a propensity score matching.

METHODS AND RESULTS

Between December 2000 and November 2005, 1,473 patients underwent isolated coronary artery bypass grafting in our institute and 153 patients who had a left ventricular ejection fraction (LVEF) lower than 35% were enrolled. The OPCAB group contained 100 patients and the On-pump CABG group contained 53 patients. Preoperative risk factors were compared and 50 patients in each group were matched. The mean follow-up time was 35.5+/-17.3 months. Three deaths (3.0%) occurred in the matched cohort, with no significant difference between 2 groups. The operation time, ventilation time, intensive care unit admission time and occurrence of respiratory failure were significantly lower in the OPCAB group. The mean LVEF of the 2 groups improved significantly. The overall 6-year actuarial survival rates of the OPCAB and On-pump CABG group were 88.2% and 72.4% (p=0.2), respectively, and there were no significant differences in 6-year rates of freedom from major adverse cardiac and cerebrovascular events (p=0.97).

CONCLUSIONS

Coronary artery bypass grafting in patients with poor left ventricular dysfunction improved myocardial function. Postoperative respiratory failure was significantly related to the cardiopulmonary bypass for surgical myocardial revascularization. Off-pump and On-pump surgical revascularization resulted in equivalent mid-term outcomes.

Surgical left ventricular remodeling in heart failure

The high mortality and morbidity of patients in terminal heart failure are a therapeutic challenge to modern medicine. Surgically, cardiac transplantation is an excellent treatment for many patients. However, lack of donors combined with an increasing number of patients has led to the search for other surgical strategies. Patients with symptomatic large left ventricular aneurysms have been treated with resection of the aneurysm and closure of the left ventricle either directly (linear closure, first reported by Cooley) or by implantation of a patch (endoventricular patch plasty or Dor procedure). Akinetic areas of the left ventricle have also been successfully treated by the latter method. According to the law of Laplace, large dilated ventricles have increased wall tension and thus increased oxygen consumption. Based on this fact, Batista and coworkers have reduced the volume of enlarged left ventricles in patients in terminal heart failure by removing a wedge of myocardium from the apex of the heart towards the base of the left ventricular free wall. Although a favorable outcome has been reported in selected patients, this method is currently not recommended for treatment of heart failure because of high surgical failure rates. The present paper reviews some of the relevant literature regarding surgical left ventricular remodeling in heart failure. Two new techniques (Myosplint and CorCap cardiac support device) are also briefly described.

Surgical Ventricular Restoration: The RESTORE Group Experience

Congestive heart failure may be caused by late left ventricular (LV) dilation following anterior infarction. Early reperfusion prevents transmural necrosis, and makes the infarcted segment akinetic rather than dyskinetic. Surgical ventricular restoration (SVR) reduces LV volume and creates a more elliptical chamber by excluding scar in either akinetic or dyskinetic segments. The international RESTORE group applied SVR in a registry of 1198 post-infarction patients between 1998 and 2003. Early and late outcomes were examined and risk factors identified.Concomitant procedures included coronary artery bypass grafting in 95%, mitral valve repair in 22%, and mitral valve replacement in 1%. Overall 30-day mortality after SVR was 5.3% (8.7% with mitral repair vs. 4.0% without repair, p < .001) Perioperative mechanical support was uncommon (< 9%). Global systolic function improved postoperatively, as ejection fraction increased from 29.6 +/- 11.0% to 39.5 +/- 12.3% (p < .001) and left ventricular end systolic volume index decreased from 80.4 +/- 51.4 ml/m(2) to 56.6 +/- 34.3 ml/m(2) (p < .001). Overall 5-year survival was 68.6 +/- 2.8%, Logistic regression analysis identified EF < or = 30%, LVESVI > o = 80 ml/m(2), advanced NYHA functional class, and age > or =75 years as risk factors for death. Five-year freedom from hospital readmission for CHF was 78%. Preoperatively, 67% of patients were class III or IV, and postoperatively 85% were class I or II.SVR improves ventricular function and is highly effective therapy in the treatment of ischemic cardiomyopathy with excellent 5-year outcome.

Reversal of ventricular dilatation in aortic regurgitation after valve replacement and cardiac support implant surgery using the CorCap cardiac support device

The effects of combined aortic valve replacement, coronary bypass surgery, and passive containment surgery in a patient with long-standing aortic regurgitation and marked ventricular dilatation are described. After surgery there was a rapid decrease in left ventricular size and maintained ventricular function.

Long-term outcome of isolated coronary artery bypass surgery in patients with severe left ventricular dysfunction

BACKGROUND

Coronary artery bypass grafting (CABG) is indicated in patients with coronary artery disease and impaired ventricular function. However, earlier studies have suggested that prognosis of patients with severe left ventricular dysfunction is extremely poor. We used the APPROACH registry to derive contemporary estimates of prognosis associated with CABG for this high-risk patient population.

METHODS AND RESULTS

The study group consisted of 7841 patients who had isolated CABG in the province of Alberta, Canada between 1996 and 2001. Patients with markedly reduced left ventricular function (ejection fraction [EF] <30%, Lo EF, n =430) were compared with those with moderate reduction in ventricular function (EF 30% to 50%, Med EF, n =2581) and those with normal left ventricular function (EF >50%, normal [Nl] EF, n=4830). The operative mortality was higher in the patient group with Lo EF (4.6%) compared with Med EF and Nl EF groups (3.4% and 1.9%, respectively, P<0.001). At 5 years, survival was 77.7% for Lo EF patients compared with 85.5% and 91.2% for Med EF and Nl EF patients, respectively (P<0.001). After controlling for other independent variables, the adjusted hazard ratio for death was 1.98 (95% CI, 1.49 to 2.62) for Lo EF relative to Nl EF. The mortality rate at 1 year was significantly lower for Lo EF patients who underwent CABG than it was for nonrevascularized Lo EF patients (risk-adjusted odds ratio, 0.36; 95% CI, 0.24 to 0.55).

CONCLUSIONS

In the modern era of cardiac surgery, CABG can be performed in Lo EF cases with an acceptable perioperative mortality risk. Our estimate of 5-year survival in this high-risk group is better than previously reported in the literature from earlier periods.

Revascularization and ventricular restoration in patients with ischemic heart failure: the STICH trial

PURPOSE OF REVIEW

As techniques for the management of patients with ischemic heart failure have evolved, controversy has arisen with respect to the roles of revascularization and ventricular restoration procedures. This review addresses current thinking on the management of these patients and describes a prospective randomized trial that will have an impact on future treatment selection.

RECENT FINDINGS

Although the basis for improved survival with coronary artery bypass grafting lies in the viability of ischemic myocardium, nuclear medicine studies and stress echocardiography have failed to adequately select for tissues that are capable of recovery. Recent studies have suggested an additional benefit to combining ventricular restoration with bypass surgery. However, the role for these techniques has not been definitively established.

SUMMARY

The currently enrolling Surgical Treatment for Ischemic Heart Failure (STICH) trial promises to address these issues and thereby improve the management of patients with this disease.

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

OBJECTIVES

The purpose of this study was to test how surgical ventricular restoration (SVR) affects early and late survival in a registry of 1,198 post-anterior infarction congestive heart failure (CHF) patients treated by the international Reconstructive Endoventricular Surgery returning Torsion Original Radius Elliptical shape to the left ventricle (RESTORE)team.

BACKGROUND

Congestive heart failure may be caused by late left ventricular (LV) dilation after anterior infarction. The infarcted segment is often akinetic rather than dyskinetic because early reperfusion prevents transmural necrosis. Previously, only dyskinetic areas were treated by operation. Surgical ventricular restoration reduces LV volume and creates a more elliptical chamber by excluding scar in either akinetic or dyskinetic segments.

METHODS

The RESTORE group applied SVR to 1,198 post-infarction patients between 1998 and 2003. Early and late outcomes were examined, and risk factors were identified.

RESULTS

Concomitant procedures included coronary artery bypass grafting in 95%, mitral valve repair in 22%, and mitral valve replacement in 1%. Overall 30-day mortality after SVR was 5.3% (8.7% with mitral repair vs. 4.0% without repair; p < 0.001). Perioperative mechanical support was uncommon (<9%). Global systolic function improved postoperatively. Ejection fraction (EF) increased from 29.6 +/- 11.0% preoperatively to 39.5 +/- 12.3% postoperatively (p < 0.001). The left ventricular end-systolic volume index (LVESVI) decreased from 80.4 +/- 51.4 ml/m(2) preoperatively to 56.6 +/- 34.3 ml/m(2) postoperatively (p < 0.001). Overall five-year survival was 68.6 +/- 2.8%. Logistic regression analysis identified EF <or=30%, LVESVI >or=80 ml/m(2), advanced New York Heart Association (NYHA) functional class, and age >or=75 years as risk factors for death. Five-year freedom from hospital readmission for CHF was 78%. Preoperatively, 67% of patients were NYHA functional class III or IV and postoperatively, 85% were class I or II.

CONCLUSIONS

Surgical ventricular restoration improves ventricular function and is highly effective therapy in the treatment of ischemic cardiomyopathy with excellent five-year outcome.

Nontransplant surgical options for congestive heart failure

Although advanced heart failure has been considered the main indication for heart transplantation, the increasing number of candidates and shortage of organs for transplantation, with accumulating waiting lists, has originated another look into more conventional surgery, previously considered of prohibitive risk. In fact, many cases are a result of anatomic lesions that can be corrected by conventional surgery, and in the past decade many surgical groups have obtained good and even excellent results in the treatment of aortic stenosis with low output, and in aortic and mitral regurgitation with severe left ventricular (LV) dysfunction. Also, ischemic and idiopathic dilated cardiomyopathy have been successfully treated by several types of LV remodeling surgery, with or without coronary grafting. Many of these procedures achieved excellent operative, medium-, and long-term results and survival, which match well those observed with cardiac transplantation, most often with advantages in the quality of life and, not unimportantly, in financial costs. For operated patients, especially those with ischemic cardiomyopathy, close follow-up for cardiac failure is extremely important in order to detect the right moment for heart transplantation, if it becomes necessary.

Reading tarot cards

In some patients acute myocardial infarction and/or infarct expansion induces progressive left ventricular dilatation that eventually leads to heart failure and death. The five year mortality after onset of heart failure is 50%. Chronically stretched viable myocardium adjacent to or remote from an expanding infarction initiates a myopathic process that leads to progressive myocyte apoptosis and adverse postinfarction remodeling. Revascularization of stunned or hibernating myocardium restores contractility and benefits patients in heart failure; however, revascularization does not restore contractility to myopathic, remodeling myocardium. Contemporary operations for heart failure temporarily reduce ventricular wall stress, but fail to reverse stretch induced myocyte apoptosis, which may not be reversible. Logically, prevention of this myopathic process after acute infarction seems required to extend survival. It follows that surgeons should operate before adverse postinfarction left ventricular remodeling occurs, using new operations, rather than afterwards.

The potential role of ventricular compressive therapy

Early infarct expansion is associated with progressive ventricular dilatation and contractile dysfunction, and heralds a poor long-term prognosis. The pathophysiology of ventricular remodeling leading to CHF is hypothesized to begin with infarct expansion, which causes increased stress in the myocardium adjacent to the infarct. Increased stress in normally perfused border zone myocardium results in the production of cytokines and ROS, which in turn stimulate myocyte apoptosis, disruption of the ECM, and fibrosis. The value of ventricular compressive therapy in established CHF with the Acorn CSD is unclear. Early clinical and laboratory studies indicate that the device can be placed safely using standard surgical techniques, and that constrictive physiology is surprisingly rare. In the few patients who have received the device, however, the clinical benefit has not been dramatic. A final assessment awaits a well-designed clinical trial comparing isolated CSD placement with optimal medical management, the primary end points being death or the need for organ replacement. In contrast, the value of early ventricular compressive therapy (ie, the prophylactic prevention of infarct expansion) has been demonstrated experimentally: early ventricular restraint dramatically ameliorates remodeling. This strategy probably represents the best application of ventricular compressive therapy. Future work must ascertain the best timing for such an intervention.

Surgical management of heart failure

This article introduces the mechanisms and theories behind the surgical treatments for heart failure; however, heart failure is a complex problem and requires multiple solutions. Surgery offers treatment strategies that target underlying physiologic changes and may provide both quality of life and survival benefit to patients who have specific clinical characteristics consistent with the aims of the procedure. Nurses must include surgical treatment early in their hierarchy of treatment plans, especially when coronary artery occlusion, hibernating myocardium, or mitral valve regurgitation is the cause of heart failure. In addition, newer investigational surgical therapies must also be considered for patients with advanced heart failure who have already been optimized on medical and cardiac resynchronization therapies and who require a novel approach to potentially improve individual outcomes.

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.

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.

Revascularization alone (without mitral valve repair) suffices in patients with advanced ischemic cardiomyopathy and mild-to-moderate mitral regurgitation

BACKGROUND

Whether or not to perform adjunctive mitral repair in patients undergoing coronary artery bypass grafting (CABG) for advanced ischemic cardiomyopathy with moderately severe mitral regurgitation (MR) remains controversial.

METHODS

We examine the clinical and echocardiographic outcome after isolated CABG in 49 patients with ischemic cardiomyopathy and 1+ to 3+ MR undergoing surgical revascularization. The patients were identified for analysis of mitral valve-related issues from a larger series of 183 patients with ischemic cardiomyopathy (MUGA ejection fraction < or = 30%) undergoing CABG by a single surgeon from 1986 to 1996. Patient age was 66.3 years (mean, range 45 to 83 years). There were 5 women (10.2%) and 44 men (89.8%). Mean ejection fraction was 22.4% with a range of 10% to 30%. Thirty-four patients had preoperative congestive heart failure (70%) and 12 (25%) had pulmonary edema. Number of grafts was 2.8 (mean, range 1 to 5). The MR was 1+ in 18 patients (37.5%), 2+ in 26 (52%) and 3+ in 5 patients (10.5%).

RESULTS

Hospital mortality was 2.0% (1 of 49 patients). Ejection fraction improved from 22.0% to 31.5% (p < 0.05) after CABG. Mean degree of MR improved with CABG alone from 1.73 to 0.54 (p < 0.05) as measured at a mean interval of 36.9 months from CABG. New York Heart-Association congestive heart failure class improved from 3.3 to 1.8 (p < 0.05). Long-term survival was 88%, 65%, and 50% at 1, 3, and 5 years postoperatively. No patient required subsequent mitral valve operation or heart transplantation in long-term follow-up.

CONCLUSIONS

We conclude that, in patients with advanced ischemic cardiomyopathy and mild-to-moderate MR, isolated CABG (without mitral valve, repair) suffices, producing dramatic improvement in ejection fraction, in congestive heart failure, and in degree of MR, with excellent (relative) long-term survival. The improvement in MR likely results from improved left ventricular function and size consequent upon revascularization.

Synergistic approaches in the surgical treatment of heart failure: complex solutions for complex problems

In the current era, with a high incidence and prevalence of heart failure, cardiologists are developing a wide range of medical therapies for this population. Working in synergy with pharmacologic therapies, surgeons are developing several innovative surgical procedures to address mechanical problems in heart failure patients that will stabilize and reverse the complex problem of heart failure.