Long-term effects of surgical ventricular restoration with additional restrictive mitral annuloplasty and/or coronary artery bypass grafting on left ventricular function: Six-month follow-up by pressure–volume loops

Clinical and hemodynamic outcomes of the Dor procedure in adults with ischemic cardiomyopathy

Ischemic cardiomyopathy continues to be a major contributor to congestive heart failure, which places a significant burden on our healthcare system. Improving medications and different coronary revascularization strategies are the mainstays in the management of ischemic cardiomyopathy. Although medications and mechanical circulatory support are playing an ever-increasing role, cardiac transplantation remains the gold standard for treating advanced heart failure. Given the small number of available and suitable donor hearts, transplantation is limited for the majority of patients. Surgical ventricular restoration has repeatedly been suggested as a viable alternative in managing heart failure in select patients, as it is believed that surgically returning the ventricle to its original dimensions is possible and associated with favorable outcomes. The purpose of this manuscript is to comprehensively review the current literature on various surgical strategies for ventricular restoration. We also contextualize the published data with respect to ventricular function, volume, structure, arrhythmias, mitral regurgitation, and clinical outcomes.

Long-Term Results of Hybrid Left Ventricular Reconstruction in the Treatment of Ischemic Cardiomyopathy

The evidence supporting surgical aneurysmectomy in ischemic heart failure is inconsistent. The aim of the study was to describe long-term effect of minimally invasive hybrid transcatheter and minithoracotomy left ventricular (LV) reconstruction in patients with ischemic cardiomyopathy. Twenty-three subjects with transmural anterior wall scarring, LV ejection fraction 15–45%, and New York Heart Association class ≥ II were intervened using Revivent TC anchoring system. LV end-systolic volume index was reduced from 73.2 ± 27 ml at baseline to 51.5 ± 22 ml after 6 months (p < 0.001), 49.9 ± 20 ml after 2 years (p < 0.001), and 56.1 ± 16 ml after 5 years (p = 0.047). NYHA class improved significantly at 5 years compared to baseline. Six-min walk test distance increased at 2 years compared to the 6-month visit. Hybrid LV reconstruction using the anchoring system provides significant and durable LV volume reduction during 5-year follow-up in preselected patients with ischemic heart failure.

Surgical ventricular restoration-meta-analysis of observational studies

Background

Technique of surgical ventricular restoration (SVR) may impact its outcomes. Therefore, we conducted a meta-analysis of studies on SVR performed by using different techniques and studied outcomes.

Methods

Scientific databases were searched for studies on SVR. End points assessed were NYHA class, left ventricular ejection fraction (LVEF), end-systolic volume index (ESVI), sphericity index, apical rotations, mortality, and re-admissions for heart failure.

Results

Circular patch use showed significant increases in LVEF by 9.53% (7.62, 11.45), decreases in ESVI by - 35.16 ml (- 44.97, - 25.34), improvements in NYHA class by - 1.29 (- 1.45, - 1.13), and decreases in sphericity index by - 0.04 (- 0.08, 0.00) . In studies using rectangular patch, the LVEF showed an increase by 5.75% (3.52, 7.98,), the NYHA class improved by - 2.45 (- 2.59, - 2.32). The decrease in ESVI was - 40.36 ml (- 62.2, - 18.52). The apical rotation increased by 3.45 ⁰ (0.62, 6.29,). Re-admission for heart failure and mortality was less.When the magnitude of ESVI decrease were compared within studies using rectangular patch, the greatest decrease in ESVI was notedwith use of a rectangular patch. (- 59 ml versus - 40 ml a very narrow patch and - 22 ml use of oval patch) The improvements in sphericity index at 2 years in use of rectangular patch study was - 0.78 ± 0.11 versus 0.00 ± 0.03 in use of oval patch study.

Conclusions

Rectangular patch use resulted in maximal decreases in ESVI and sphericity index. Mortality and re-admissions for heart failure were also significantly less at mid-term after SVR.

Right and left ventricular 24-segment sphericity index is abnormal in small-for-gestational-age fetuses

OBJECTIVE

Fetuses with growth restriction have been reported to have an abnormal sphericity index (SI), which is indicative of the shape of the ventricular chambers of the heart. Our aim was to evaluate the SI for 24 transverse segments distributed from base to apex of the right (RV) and left (LV) ventricles to determine whether, in small-for-gestational-age (SGA) fetuses, the SI is abnormal at locations other than the basal segment.

METHODS

We evaluated 30 SGA fetuses between 25 and 37 weeks of gestation. SI was computed for both ventricles by dividing the end-diastolic mid-basal-apical length by each of 24 end-diastolic transverse segmental widths, from base (Segment 1) to apex (Segment 24). For each ventricle, the Z-score and centile for the SI from each of the 24 segments were computed using the mean and SD from published equations. The 24-segment method, defining abnormal SI as values < 10^th centile or > 90^th centile, was compared with that of using only the basal segment by chi-square analysis to determine the number of fetuses identified with an abnormal SI.

RESULTS

In 23 of the 30 (77%) SGA fetuses, at least one of the 24 transverse segments in one or both ventricles had an abnormal SI; in 17% of cases, both ventricles were affected, in 23% of cases only the RV was involved and in 37% of cases only the LV was involved. Compared with the 24-segment model, significantly fewer fetuses with an abnormal SI were identified using only basal Segment 1, from the RV base (58%, 7/12; P < 0.01) or only Segment 12, in the mid portion of the RV (50%, 6/12; P < 0.005). Combining measurements of Segment 1 and Segment 12 from the RV identified 83% of fetuses with at least one abnormal SI and was not significantly different from using the 24-segment model. Similarly, significantly fewer fetuses with an abnormal SI were identified using only LV basal Segment 1 (63%, 10/16; P < 0.006) or only Segment 12, in the mid portion of the LV (75%, 12/16; P < 0.03), when compared with the 24-segment model. Combining measurements of both LV Segment 1 and Segment 12 identified 81% (13/16) of fetuses with an abnormal SI and was not significantly different from using the 24-segment model.

CONCLUSION

The 24-segment SI of RV and LV provides a comprehensive method with which to examine the shape of the ventricular chambers and identifies more SGA fetuses with an abnormal SI than are identified using only the basal segment SI. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

24-segment sphericity index: a new technique to evaluate fetal cardiac diastolic shape

OBJECTIVE

Because of parallel circulation in the fetus and the differential effect that various disease states may have on the shape of the right and left ventricles, this study was conducted to evaluate the sphericity index (SI) of 24 transverse segments distributed from the base to the apex of each of the ventricular chambers.

METHODS

Two hundred control fetuses were examined between 20 and 40 weeks of gestation. The displacement of the ventricular endocardium during the cardiac cycle was computed using offline speckle-tracking software. From the ASCII output of the analysis, we analyzed 24 end-diastolic transverse segments, distributed from the base to the apex of each ventricle, as well as the end-diastolic mid-basal-apical length. The SI was computed for each of the 24 segments by dividing the mid-basal-apical length by the transverse length for each segment. Regression analysis was performed against biometric measurements and gestational age according to last menstrual period and ultrasound. Eight fetuses, in which the four-chamber view appeared subjectively to demonstrate chamber disproportion, were evaluated as examples to demonstrate the utility of this technology.

RESULTS

The SI for each segment was independent of gestational age and fetal biometric measurements. The SI of the right ventricle was significantly (P < 0.001) lower than that of the left ventricle for segments 1-18, suggesting that the right ventricle was more globular in shape than was the left ventricle at the base, mid and a portion of the apical segments of the chamber. Fetuses with various cardiac structural abnormalities and abnormal fetal growth had abnormal SI values that reflected either a more globular or a more flattened ventricular chamber.

CONCLUSION

Determination of SI for each of 24 segments of the fetal right and left ventricles provides a comprehensive method to examine the shape of the ventricular chambers. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Abnormal Fetal Findings Associated With a Global Sphericity Index of the 4-Chamber View Below the 5th Centile

OBJECTIVES

The purpose of this study was to evaluate the global sphericity index (GSI) of the 4-chamber view and correlate the results with abnormal ultrasound findings.

METHODS

The epicardial end-diastolic basal-apical length (BAL) and transverse length (TL) of the 4-chamber view were measured to compute the GSI (BAL/TL) in 200 control fetuses between 20 and 40 weeks' gestation. Three hundred study fetuses were prospectively examined between 17 and 39 weeks' gestation. The GSI, Z score, and centile were computed for each of the fetuses.

RESULTS

The GSI (1.233; SD, 0.0953) in the control fetuses was independent of gestational age. Eighteen percent of the study fetuses (55 of 300) had a GSI below the 5th centile (<1.08), of whom 96% (53 of 55) had additional abnormal ultrasound findings. Fetuses with an estimated fetal weight below the 10th centile had a significantly (P < .05) higher rate of an umbilical artery Doppler pulsatility index above the 95th centile (27% versus 17.7%), a middle cerebral artery Doppler pulsatility index below the 5th centile (27% versus 0%), an abnormal cerebroplacental ratio (27% versus 4.5%), and an amniotic fluid index of less than 5 cm (36% versus 9%). The TL was significantly increased compared with the BAL in fetuses with cardiac dysfunction, irrespective of the estimated fetal weight.

CONCLUSIONS

An abnormal GSI below the 5th centile is associated with abnormal fetal ultrasound findings.

Outcome of left ventricular surgical remodelling after the STICH trial

OBJECTIVES

After the publication of the Surgical Treatment for Ischaemic Heart Failure (STICH) trial, surgical indications to left ventricular surgical remodelling (LVSR) have become more restrictive. The experience we report reflects the changes in the real world after the publication of STICH trial.

METHODS

From May 2009 to July 2014, 113 patients underwent LVSR, targeted mainly to the left anterior descending territory (89.4%). Of these, 18 patients (15.9%) were operated on an emergency basis. Early and mid-term outcomes were assessed to identify clinical and echocardiographic risk factors.

RESULTS

Most patients (90.3%) had chronic ischaemic mitral regurgitation (CIMR) and were in New York Heart Association (NYHA) class III/IV (77.9%). The median ejection fraction (EF) was 26% [95% confidence interval (CI): 26, 28] and scarred areas were akinetic (86.7%) in most cases. Severe left ventricular diastolic dysfunction (LVDD) was found in 33.6% of patients. Mitral valve surgery was performed in 84.1% of patients. Five patients (4.4%) died while in hospital, all from cardiac causes. Risk factors were abnormal bilirubin and emergency status. After a median follow-up of 12 (95% CI: 6, 18) months, 22 patients died, 17 from cardiac causes. Five-year freedom from death any from cause was 73 ± 5%, emergency status and MR Grade 4 being the only risk factors. Five-year freedom from death from any cause and NYHA class III/IV was 61 ± 6%. Severe LVDD and emergency status were risk factors, along with high bilirubin and diabetes mellitus on insulin. Five-year freedom from death from any cause and non-fatal cardiovascular events (rehospitalization, reoperation and stroke) was 55 ± 6%. LVDD and atrial fibrillation were found to be risk factors. After a median follow-up of 31 (95% CI: 19, 38) months, 91 patients underwent postoperative echocardiography. EF increased by 20%, but stroke volume remained unchanged. Postoperatively, patients with severe LVDD had lower EF and higher end-systolic volumes than patients without LVDD.

CONCLUSIONS

Our findings show that patients, who are candidates for LVSR, have mostly akinetic areas and CIMR requiring surgical correction and are severely symptomatic. Severe LVDD is common and, along with emergency status, is the most important risk factor for early and late outcome.

Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops

Introduction

The American Heart Association (AHA)/American College of Cardiology (ACC) guidelines for the classification of heart failure (HF) are descriptive but lack precise and objective measures which would assist in categorising such patients. Our aim was two fold, firstly to demonstrate quantitatively the progression of HF through each stage using a meta-analysis of existing left ventricular (LV) pressure-volume (PV) loop data and secondly use the LV PV loop data to create stage specific HF models.

Methods and Results

A literature search yielded 31 papers with PV data, representing over 200 patients in different stages of HF. The raw pressure and volume data were extracted from the papers using a digitising software package and the means were calculated. The data demonstrated that, as HF progressed, stroke volume (SV), ejection fraction (EF%) decreased while LV volumes increased. A 2-element lumped parameter model was employed to model the mean loops and the error was calculated between the loops, demonstrating close fit between the loops. The only parameter that was consistently and statistically different across all the stages was the elastance (Emax).

Conclusions

For the first time, the authors have created a visual and quantitative representation of the AHA/ACC stages of LVSD-HF, from normal to end-stage. The study demonstrates that robust, load-independent and reproducible parameters, such as elastance, can be used to categorise and model HF, complementing the existing classification. The modelled PV loops establish previously unknown physiological parameters for each AHA/ACC stage of LVSD-HF, such as LV elastance and highlight that it this parameter alone, in lumped parameter models, that determines the severity of HF. Such information will enable cardiovascular modellers with an interest in HF, to create more accurate models of the heart as it fails.

Understanding the need of ventricular pressure for the estimation of diastolic biomarkers

The diastolic function (i.e., blood filling) of the left ventricle (LV) is determined by its capacity for relaxation, or the decay in residual active tension (AT) generated during systole, and its constitutive material properties, or myocardial stiffness. The clinical determination of these two factors (diastolic residual AT and stiffness) is thus essential for assessing LV diastolic function. To quantify these two factors, in our previous work, a novel model-based parameter estimation approach was proposed and successfully applied to multiple cases using clinically acquired motion and invasively measured ventricular pressure data. However, the need to invasively acquire LV pressure limits the wide application of this approach. In this study, we address this issue by analyzing the feasibility of using two kinds of non-invasively available pressure measurements for the purpose of inverse mechanical parameter estimation. The prescription of pressure based on a generic pressure-volume (P-V) relationship reported in literature is first evaluated in a set of 18 clinical cases (10 healthy and 8 diseased), finding reasonable results for stiffness but not for residual active tension. We then investigate the use of non-invasive pressure measures, now available through imaging techniques and limited by unknown or biased offset values. Specifically, three sets of physiologically realistic synthetic data with three levels of diastolic residual active tension (i.e., impaired relaxation capability) are designed to quantify the percentage error in the parameter estimation against the possible pressure offsets within the physiological limits. Maximum errors are quantified as 11 % for the magnitude of stiffness and 22 % for AT, with averaged 0.17 kPa error in pressure measurement offset using the state-of-the-art non-invasive pressure estimation method. The main cause for these errors is the limited temporal resolution of clinical imaging data currently available. These results demonstrate the potential feasibility of the estimation diastolic biomarkers with non-invasive assessment of pressure through medical imaging data.

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."

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.

Influence of baseline left ventricular function on the clinical outcome of surgical ventricular reconstruction in patients with ischaemic cardiomyopathy

AIMS

The Surgical Treatment for Ischemic Heart Failure (STICH) trial demonstrated no overall benefit when surgical ventricular reconstruction (SVR) was added to coronary artery bypass grafting (CABG) in patients with ischaemic cardiomyopathy. The present analysis was to determine whether, based on baseline left ventricular (LV) function parameters, any subgroups could be identified that benefited from SVR.

METHODS AND RESULTS

Among the 1000 patients enrolled, Core Lab measures of baseline LV function with adequate quality were obtained in 710 patients using echocardiography, in 352 using cardiovascular magnetic resonance, and in 344 using radionuclide imaging. The relationship between LV end-systolic volume index (ESVI), end-diastolic volume index, ejection fraction (EF), regional wall motion abnormalities, and outcome were first assessed only by echocardiographic measures, and then by 13 algorithms using a different hierarchy of imaging modalities and their quality. The median ESVI and EF were 78.0 (range: 22.8-283.8) mL/m2 and 28.0%, respectively. Hazard ratios comparing the randomized arms by subgroups of LVESVI and LVEF measured by echocardiography found that patients with smaller ventricles (LVESVI <60 mL/m2) and better LVEF (≥33%) may have benefitted by SVR, while those with larger ventricles (LVESVI >90 mL/m(2)) and lower LVEF (≤25%) did worse with SVR. Algorithms using all three imaging modalities found a weaker relationship between LV global function and the effects of SVR. The extent of regional wall motion abnormality did not influence the effects of SVR.

CONCLUSIONS

Subgroup analyses of the STICH trial suggest that patients with less dilated LV and better LVEF may benefit from SVR, while those with larger LV and poorer LVEF may do worse. Clinical Trial Registration #: NCT00023595.