MD Cecilia Linde
email: cecilia.linde@ki.se

MD Claude Daubert

MD William T Abraham

Martin St

MD John Sutton

MD Stefano Ghio

MD Christian Hassager

MD John M Herre

PhD Tracy L Bergemann

MD Michael R Gold

Impact of Ejection Fraction on the Clinical Response to Cardiac Resynchronization Therapy in Mild Heart Failure

Keywords: Clinicaltrials.gov identifier NCT00271154 Cardiac resynchronization therapy, Heart failure, Electrical dyssynchrony, Mortality CCS= clinical composite score CRT= Cardiac resynchronization therapy ECG= electrocardiogram

établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

INTRODUCTION

Cardiac Resynchronization Therapy (CRT) is well established for patients with severe left ventricular systolic dysfunction and ventricular conduction delay in advanced heart failure (HF) [1][START_REF] Abraham | Multicenter InSync Randomized Clinical Evaluation. Cardiac resynchronization in chronic heart failure[END_REF][3][4][START_REF]LV mass is n=202[END_REF][6][7] . More recently, the benefit of CRT was expanded to patients with mild HF, with improved functional status and reductions in hospitalization and mortality observed [8][9][START_REF] Daubert | Prevention of Disease Progression by Cardiac Resynchronization Therapy in Patients with Asymptomatic or Mildly Symptomatic Left Ventricular Dysfunction. Insight from the European cohort of the REVERSE trial[END_REF][START_REF] Moss | Cardiac-resynchronization therapy for the prevention of heart-failure events[END_REF][START_REF] Tang | Resynchronization-Defibrillation for Ambulatory Heart Failure Trial Investigators. Cardiac-Resynchronization Therapy for Mild-to-Moderate Heart Failure[END_REF] . The most consistent response was noted in subgroups with left bundle branch block (LBBB) and more prolonged baseline QRS duration [START_REF] Zareba | Effectiveness of cardiac resynchronization therapy by QRS morphology in the multicenter automatic defibrillator implantation trial -Cardiac resynchronization therapy (MADIT-CRT)[END_REF][START_REF] Gold | The Effect of QRS Duration and Morphology on Cardiac Resynchronization Therapy Outcomes in Mild Heart Failure: Results from the Resynchronization reVErses Remodeling in Systolic left vEntricular dysfunction (REVERSE) Study[END_REF] . However, the effect of left ventricular ejection fraction (LVEF) on CRT outcomes is less clear. Based on these results, current guidelines recommend CRT as a Class I indication for subjects with mild heart failure, LBBB and LVEF < 35 [START_REF] Stevenson | From the Heart Failure Society of America Guideline Committee. Indications for cardiac resynchronization therapy: 2011 update from the Heart Failure Society of America guideline committee[END_REF][START_REF] Tracy | ACCF/AHA/HRS Focused Update of the 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines[END_REF] or 30% [START_REF] Mcmurray | ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2012: The Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2012 of the European Society of Cardiology. Developed in collaboration with the Heart Failure Association (HFA) of the ESC[END_REF] with LVEF criteria based on the inclusion criteria in the studies [START_REF] Stevenson | From the Heart Failure Society of America Guideline Committee. Indications for cardiac resynchronization therapy: 2011 update from the Heart Failure Society of America guideline committee[END_REF][START_REF] Tracy | ACCF/AHA/HRS Focused Update of the 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines[END_REF][START_REF] Mcmurray | ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2012: The Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2012 of the European Society of Cardiology. Developed in collaboration with the Heart Failure Association (HFA) of the ESC[END_REF] .

Of the three multicenter, randomized trials of CRT in mild HF, only REVERSE included subjects with EF > 30%. To determine whether CRT is effective in less severe left ventricular systolic dysfunction, the impact of EF on outcomes in REVERSE was studied. Specifically, we hypothesized that the benefit from CRT would be similar in patients with moderate LV dysfunction (LVEF > 30%) as in those with severe LV dysfunction (LVEF < 30%).

METHODS

Study design and data collection:

REVERSE was a prospective, randomized, double-blind, parallel-controlled study designed to determine whether CRT limited the progression of heart failure compared to optimal medical therapy alone. The study included ACC/AHA stage C, NYHA Class I or II heart failure patients with QRS ≥ 120ms, and LVEF ≤ 40% on optimal medical therapy. Patients were implanted with a CRT device with (CRT-D) or without (CRT-P) defibrillator and randomized 2:1 to CRT ON versus CRT OFF. Devices were then programmed as randomized through 12 months in North America and through 24 months in Europe. The rationale of the REVERSE study has been published previously [START_REF] Linde | Rationale and design of a randomized controlled trial to assess the safety and efficacy of cardiac resynchronization therapy in patients with asymptomatic left ventricular dysfunction with previous symptoms or mild heart failure--the REsynchronization reVErses Remodeling in Systolic left vEntricular dysfunction (REVERSE) study[END_REF] . For the present analysis, patients were grouped by LVEF > 30% or < 30%, by core lab evaluation.

Outcomes:

The primary endpoint of the REVERSE main study was the percentage of patients at 12 months with a worsened HF clinical composite score [START_REF] Packer | Proposal for a new clinical end point to evaluate the efficacy of drugs and devices in the treatment of chronic heart failure[END_REF] (CCS), which scores patients as improved, unchanged, or worsened. The prospectively powered secondary endpoint was LV end-systolic volume index (LVESVi). Other secondary endpoints were hospitalization for worsening HF and mortality and additional measures of reverse remodeling. Quality of life was measured by the Minnesota Living with Heart Failure Questionnaire (MLHFQ) [START_REF] Rector | Patient's self-assessment of their congestive heart failure. Part 2: content, reliability, and validity of a new measure, The Minnesota Living with Heart Failure questionnaire[END_REF] and the Kansas City Cardiomyopathy questionnaire (KCCQ) [START_REF] Green | Development and evaluation of the Kansas City Cardiomyopathy Questionnaire: a new health status measure for heart failure[END_REF] . During the blinded period patients were evaluated every 6 months, by blinded staff collecting NYHA class, 6-minute hall walk, quality of life, echocardiographic data, HF-related hospitalizations and mortality data. Heart failure hospitalizations were adjudicated for heart failure relatedness by the endpoint adjudication committee blinded to CRT assignment. This committee also adjudicated causes of death.

Likewise, echocardiograms were assessed by two core labs blinded to CRT assignment, one in the US and one in Europe [START_REF] Linde | Rationale and design of a randomized controlled trial to assess the safety and efficacy of cardiac resynchronization therapy in patients with asymptomatic left ventricular dysfunction with previous symptoms or mild heart failure--the REsynchronization reVErses Remodeling in Systolic left vEntricular dysfunction (REVERSE) study[END_REF] .

Statistical methods:

Statistical analyses followed the intent-to-treat principle. All p-values reported are two-sided and do not adjust for multiple comparisons. The primary endpoint was tested with a Fisher's exact test that compared the full distribution of clinical composite scores at 12 months by randomization group. The same testing procedure was used to assess NYHA class at 12 months. Kaplan-Meier curves were estimated for the combined endpoint of time to death or first HF hospitalization. Time 0 was the date of randomization. Since the length of the randomization period in the study differed by geography (12 months in North America and 24 months in Europe), patients without an observed event were censored at the end of their randomization period. Kaplan-Meier curves are truncated when fewer than 20 patients are at risk for a time point. A log-rank test compared survival curves between randomization groups. To assess CRT effects on time to death or HF hospitalization modified by LVEF subgroup, a Cox model was fit with main effects for CRT and LVEF subgroup and an interaction effect between them. The Cox model was then adjusted for other potentially confounding variables such as of age, intrinsic QRS duration, LVESVi, ischemic heart disease, and blood pressure at baseline. There were 43 patients with missing values for confounding factors that were discarded from the multivariable analysis. Within LVEF subgroup, changes between baseline and 12 months in LVEDVi, LVESVi, LVEF, LVEDD, LV mass, MLWHF, KCCQ and the 6-minute hall walk were compared between randomization groups with a two-sample t-test assuming unequal variances.

Finally, regression towards the mean [START_REF] Barnett | Regression to the mean: what it is and how to deal with it[END_REF] is a real concern in subgroup analysis where patients are divided into high and low groups. To adjust for this effect, an ANCOVA model was fit for each echo parameter where the outcome was the difference over time, the independent variable was CRT and the confounding variable was the baseline value of the echo parameter. Statistical analyses were conducted in R (http://www.r-project.org) and SAS 9.2 (SAS Institute, Cary, North Carolina).

RESULTS

Patient Characteristics:

The baseline characteristics of the entire cohort and the main results were reported previously 9,[START_REF] Daubert | Prevention of Disease Progression by Cardiac Resynchronization Therapy in Patients with Asymptomatic or Mildly Symptomatic Left Ventricular Dysfunction. Insight from the European cohort of the REVERSE trial[END_REF][START_REF] Barnett | Regression to the mean: what it is and how to deal with it[END_REF] 12. Patients with LVEF > 30% were significantly older, more often had ischemic etiology, worse renal function and higher systolic blood pressure. Nonetheless, they were more often in NYHA I, and had smaller LV dimensions and volumes and lower LV mass than those with LVEF < 30%. Moreover, quality of life both by the MLHFQ score and KCCQ and six minute walk distance tended to be better in the LVEF > 30% group. Although QRS duration was significantly shorter in the LVEF > 30% group than in the LVEF < 30% group (147±20.4 ms vs 155.7 ± 22.2 ms; p<0.0001), the presence of LBBB was comparable between subgroups (58% vs 62%, respectively, p= 0.31). Both subgroups were well treated medically with most patients receiving both beta blockers and ACE inhibitors or angiotensin receptor blocker agents at baseline.

Echocardiographic Measurements:

The echocardiographic results are summarized in Figure 2 and in Table 3. Overall the magnitude of improvement was smaller in the LVEF > 30% group than in the LVEF < 30% group. A significant decrease of LVESVi after 12 months of CRT was observed in both LVEF subgroups compared to CRT OFF. A trend toward significant reduction in LVEDVi by CRT ON was observed in the LVEF > 30% group (-11.2 ± 27.0 ml/m 2 vs -4.3 ± 22.9 ml/m 2 in CRT OFF; p=0.12). A statistically significant decrease of LVEDVi and a significant increase in LVEF was only observed in the LVEF < 30% group. Adjusting for the potential effect of regression to the mean did not affect the interpretation of the reverse remodeling results (Table 4).

Clinical Measurements:

The clinical results at 12 months are shown in Table 3 andFigure 3. In the LVEF > 30% group the distribution of the CCS was better in CRT ON compared to OFF (p=0.06) but did not reach statistical significance. A statistically significant improvement was observed in the LVEF ≤ 30% group and in the full study group. In the overall group there was a significant improvement in NYHA class with CRT-ON (p=0.04). Although the numerical trends in the EF subgroups were in the same direction it did not reach statistical significance in either group.

Effect of CRT on time to first HF hospitalization or death in EF<=30 versus >30:

Time to first HF hospitalization or death was tracked through 12 months (North America) or 24 months (Europe) and is shown in Figure 4. Overall the composite morbidity and mortality rate was nearly twice as high in the LVEF < 30% group; Death occurred in 3.7% of patients and 11.8% experienced the composite endpoint of HF hospitalization or death during the randomization period. Comparatively, in the LVEF > 30% group, 1.7% of patients died and 6.8% of patients experienced a HF hospitalization or death during the randomization period.

There were significant prolonged time to first hospitalization for HF or death for CRT ON vs CRT OFF in both the LVEF ≤ 30% (p= 0.047, hazard ratio=0.58) and > 30% group (p=0.012, hazard ratio=0.26) with curves for CRT ON and OFF separating early within the first months (Figure 4).

In the LVEF < 30% group there were 16 deaths: 6 /141 patients in CRT OFF due to progressive HF, arrhythmia, stroke, electromechanical dissociation, renal cancer and by cause unknown and 10 /290 patients in CRT ON due to progressive HF (n=3), arrhythmia, bradyarrhythmia, pulmonary fibrosis, stroke, prostate cancer, and by cause unknown (n=2). In the LVEF > 30% group there were 3 deaths: 1/50 patients in CRT OFF (gastrointestinal bleeding) and 2/127 patients in CRT ON (gastrointestinal bleeding and pulmonary fibrosis). The effect of the interaction between CRT and LVEF subgroup on time to death or HF hospitalization was also assessed.

As there were some baseline differences between the two LVEF subgroups, a multivariable analysis was performed to adjust for potential confounding factors (Table 5). After adjusting for important covariates, the main effect for CRT assignment remained independently associated (p=0.035, hazard ratio=0.54) with improved outcomes among patients assigned to CRT ON.

There was no statistically significant interaction between CRT and LVEF indicating that there was no evidence that the benefit of CRT varied with LVEF. Baseline LVESVi (p=0.0002) and QRS duration (p=0.003) were also independently associated with hospitalization for HF or death with better outcome in subjects with smaller left ventricular size and longer QRS duration. The etiology of heart disease (i.e. ischemic vs nonischemic) was not associated with outcome in this analysis.

DISCUSSION

The primary results of the present analysis show that the beneficial effect of CRT-ON on ventricular function and on time to death or first hospitalization occurs across the full spectrum of LVEF studied in REVERSE, with no sign that it is weaker in patients with LVEF>30 than those with LVEF<=30. These findings are strengthened by the randomized design of the study, with blinded comparison against CRT-OFF, and the rigorous exclusion of regression to the mean as a contributing factor.

Sub-studies of CRT results by different ejection fractions

In previous sub-studies of randomized controlled studies, no apparent difference in CRT benefit was observed in patients with LVEF > 20% or < 20% in moderate to severe 4,[START_REF]LV mass is n=202[END_REF] and mild [START_REF] Moss | Cardiac-resynchronization therapy for the prevention of heart-failure events[END_REF][START_REF] Tang | Resynchronization-Defibrillation for Ambulatory Heart Failure Trial Investigators. Cardiac-Resynchronization Therapy for Mild-to-Moderate Heart Failure[END_REF] heart failure. Similar observations were made in a retrospective analysis of the PROSPECT study evaluating less severe LV dysfunction and an analysis of single center data [START_REF] Chung | Cardiac resynchronization therapy may benefit patients with left ventricular ejection fraction > 35%: a PROSPECT trial sub-study[END_REF][START_REF] Foley | Cardiac resynchronization therapy in patients with mildly impaired left ventricular function[END_REF] . PROSPECT [START_REF] Chung | Results of the predictors of response to CRT (PROSPECT) trial[END_REF] was an open-label study which included patients with NYHA class III-IV, QRS > 130 ms and LVEF < 35%. CRT induced similar benefit among patients with LVEF < 35% or LVEF > 35% with regard to reverse remodeling and the percentage improved by the CCS. Importantly, a recently published post hoc analysis of MADIT-CRT [START_REF] Kutyifa | The influence of left ventricular ejection fraction on the effectiveness of cardiac resynchronization therapy: MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy)[END_REF] of NYHA I-II patients also indicated a benefit of CRT in the subjects with LVEF > 30% in the study. As in our study and in PROSPECT [START_REF] Chung | Results of the predictors of response to CRT (PROSPECT) trial[END_REF] , core lab evaluation resulted in some subects with higher LVEF than allowed by the study inclusion criteria. In agreement with our findings, the clinical benefit for time to HF hospitalizations or death was greater for the patients with LVEF > 30% compared to the other LVEF groups [START_REF] Kutyifa | The influence of left ventricular ejection fraction on the effectiveness of cardiac resynchronization therapy: MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy)[END_REF] . However, in contrast to our findings, the extent of reverse remodeling defined as decrease of LVESVi was higher for the LVEF > 30% patients [START_REF] Kutyifa | The influence of left ventricular ejection fraction on the effectiveness of cardiac resynchronization therapy: MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy)[END_REF] than for the other groups in spite of smaller baseline LV. The reason for this discrepancy is not clear, although subjects with less severe LV dysfunction were included in REVERSE.

Results in the present study with regard to LVEF

To our knowledge, only REVERSE included patients with LVEF < 40%. In fact 12.2% (n=74) of our patients had LVEF > 35%, i.e. with LVEFs beyond the current guideline recommendations in the US [START_REF] Stevenson | From the Heart Failure Society of America Guideline Committee. Indications for cardiac resynchronization therapy: 2011 update from the Heart Failure Society of America guideline committee[END_REF][START_REF] Tracy | ACCF/AHA/HRS Focused Update of the 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines[END_REF] . In contrast, a smaller fraction of patients in the MADIT CRT sub-study had LVEF > 35%. Our results show some signs of significant reverse remodeling benefits by CRT at 12 months regardless of whether baseline LVEF was below or above 30%. In this study the patients with higher LVEF were more often older, had more ischemic heart disease and worse renal function implying negative prognostic impact. However, they were more often in NYHA I functional class and had smaller baseline LV volumes than patients with LVEF < 30%.

Moreover, multivariate analysis indicated that a smaller LVESVi at baseline was linked to greater magnitude of response to CRT which also suggests earlier intervention with CRT than indicated in present guidelines [START_REF] Stevenson | From the Heart Failure Society of America Guideline Committee. Indications for cardiac resynchronization therapy: 2011 update from the Heart Failure Society of America guideline committee[END_REF][START_REF] Tracy | ACCF/AHA/HRS Focused Update of the 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines[END_REF][START_REF] Mcmurray | ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2012: The Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2012 of the European Society of Cardiology. Developed in collaboration with the Heart Failure Association (HFA) of the ESC[END_REF] . The magnitude of reverse remodeling in the higher LVEF group was less than observed in patients with severe heart failure and with worse LV function in the post hoc analysis of PROSPECT [START_REF] Chung | Cardiac resynchronization therapy may benefit patients with left ventricular ejection fraction > 35%: a PROSPECT trial sub-study[END_REF] . One contributing factor for this observation may be that patients in this group more often had underlying ischemic heart disease and shorter QRS duration which is known to be linked to less extensive reverse remodeling 6,14,28,29 . In the MIRACLE trial, the extent of reverse remodeling was half the magnitude in patients with ischemic etiology as in those with dilated cardiomyopathy [START_REF] Sutton | Sustained reverse left ventricular structural remodelling with cardiac resynchronisation therapy at one year is a function of etiology: quantitative Doppler echocardiographic evidence from the Multicentre InSync Randomized Clinical Evaluation (MIRACLE)[END_REF] . Similar findings were made in the CARE-HF trial despite similar clinical benefit [START_REF] Wikström | The effects of aetiology on outcome in patients treated with cardiac resynchronisation therapy in the CARE-HF trial[END_REF] . We have previously reported that ischemic heart failure patients in REVERSE had three times less reverse remodeling than patients with dilated cardiomyopathy [START_REF] Linde | behalf of the REVERSE study group. Cardiac resynchronization therapy in asymptomatic or mildly symptomatic heart failure patients in relation to etiology: results from the REVERSE (Resynchronization reVErses Remodeling in Systolic Left vEntricular Dysfunction) study[END_REF] and that the magnitude of the QRS duration is an independent predictor of the extent of reverse remodeling [START_REF] Gold | The Effect of QRS Duration and Morphology on Cardiac Resynchronization Therapy Outcomes in Mild Heart Failure: Results from the Resynchronization reVErses Remodeling in Systolic left vEntricular dysfunction (REVERSE) Study[END_REF] . The effect of QRS duration and etiology of heart failure on reverse remodeling has also been noted in studies of advanced HF [START_REF] Ellenbogen | Primary results from the SmartDelay determined AV optimization: a comparison to other AV delay methods used in cardiac resynchronization therapy (SMART-AV) trial: a randomized trial comparing empirical, echocardiography-guided, and algorithmic atrioventricular delay programming in cardiac resynchronization therapy[END_REF] . Thus, the greater proportion of patients with ischemic etiology and shorter mean QRS duration in the LVEF > 30% group may partly explain the smaller reverse remodeling.

Nonetheless, CRT in LVEF > 30% was associated with significant clinical improvement as assessed by the time to mortality or hospitalizations for heart failure as in the LVEF < 30% group over a follow up period of 12-24 months. In fact, the relative risk reduction was 74% in the LVEF > 30% group compared to 42% in the LVEF < 30% group suggesting a greater benefit. CRT was independently associated with outcome independent of LVEF. Age or baseline ischemic heart disease and diabetes were not independent predictors of clinical outcome.

Electrical dyssynchrony is critical for CRT induced improvements with the response increasing with longer intrinsic QRS duration and in particular left bundle branch morphology [START_REF] Zareba | Effectiveness of cardiac resynchronization therapy by QRS morphology in the multicenter automatic defibrillator implantation trial -Cardiac resynchronization therapy (MADIT-CRT)[END_REF][START_REF] Gold | The Effect of QRS Duration and Morphology on Cardiac Resynchronization Therapy Outcomes in Mild Heart Failure: Results from the Resynchronization reVErses Remodeling in Systolic left vEntricular dysfunction (REVERSE) Study[END_REF] . Our patients all had wide QRS (155.7 ± 22.2 ms in the LVEF < 30% and 147±20.4 ms in the LVEF > 30% group) and LBBB was present in about 60% of patients within each subgroup. These study results indicate that the benefits of CRT may be present for patients with QRS prolongation and mild HF with less severe left ventricular dysfunction than previously studied.

Presence of electrical dyssynchrony in HF patients with reduced and preserved LVEF

Approximately one third of HF patients have conduction disturbances evidenced by QRS duration > 120 ms [START_REF] Baldasseroni | Italian Network on Congestive Heart Failure Investigators. Left bundle-branch block is associated with increased 1-year sudden and total mortality rate in 5517 outpatients with congestive heart failure: a report from the Italian network on congestive heart failure[END_REF][START_REF] Lund | Prevalence, correlates and prognostic significance of QRS prolongation in heart failure with reduced and preserved ejection fraction[END_REF][START_REF] Schneider | Newly acquired left bundle-branch block: the Framingham study[END_REF] . Although electrical dyssynchrony is more common in HF patients with reduced LVEF it is prevalent over a wide range of ejection fractions [START_REF] Lund | Prevalence, correlates and prognostic significance of QRS prolongation in heart failure with reduced and preserved ejection fraction[END_REF] and linked to worse prognosis [START_REF] Lund | Prevalence, correlates and prognostic significance of QRS prolongation in heart failure with reduced and preserved ejection fraction[END_REF][START_REF] Schneider | Newly acquired left bundle-branch block: the Framingham study[END_REF] . In a recent report from the Swedish heart failure registry 33 39% of patients with LVEF< 40% , 25% with LVEF 40-49% and 18% of patients with LVEF > 50% had QRS duration > 120 ms that was associated with risk for mortality regardless of ejection fraction.

Similar observations were made in the CHARM studies also including mild heart failure patients [START_REF] Hawkins | Prevalence and prognostic impact of bundle branch block in patients with heart failure; evidence from the CHARM program[END_REF] . These observations indicate that electrical dyssynchrony is present in HF patients with mild to moderate reduction in ventricular function and potentially might be influenced by CRT.

The findings in the present analysis of HF patients with LVEF 31-40% are encouraging.

Limitations:

The study should be interpreted in light of certain methodological limitations. This was a posthoc subgroup analysis that was not powered during study design and randomization was not stratified based on EF. There were also some important clinical differences between subgroups, although multivariate analysis indicated that EF was not an independent predictor of response.

Conclusions:

In this analysis of REVERSE study patients with LVEF > 30%, CRT produced improvements in time to death or heart failure related hospitalizations and were associated with significant reduction in left ventricular end-systolic volume index and left ventricular mass consistent with reverse remodeling. These findings warrant further prospective validation. 3 Sample sizes for LVEDD and LVESD are n=298 (LVEF < 30%) and n=114 (LVEF > 30%) 4 Sample sizes for LV mass are n=281 (LVEF < 30%) and n=94 (LVEF > 30%) [START_REF]LV mass is n=202[END_REF] Sample sizes for MLWHF are n=420 (LVEF < 30%) and n=164 (LVEF > 30%) 6 Sample sizes for KCCQ are n=374 (LVEF < 30%) and n=146 (LVEF > 30%)

7 Sample sizes for 6-min hall walk are n=425 (LVEF < 30%) and n=176 (LVEF > 30%)

5 .Figure 1 .

 51 Figure 1. Distribution of center lab (top) and core lab (bottom) baseline left ventricular ejection

Figure 2 .

 2 Figure 2. Left ventricular reverse remodeling of LVESVi and LVEF with baseline LVEF > 30%

Figure 3 .

 3 Figure 3. Clinical composite response distribution in patients with baseline LVEF < 30% or >

Figure 4 .

 4 Figure 4. Time to death or hospitalization for heart failure in patients with baseline LVEF < 30%

baseline is shown in Figure 1. Consistent with clinical practice, the centers tended to report LVEF values in multiple of 5 (61.2%) or 10 (33.4%). Baseline characteristics grouped by LVEF are shown in Tables

  . LVEF was available in 608 of the 610 randomized patients, in 565 subjects by

	core lab measurement and in 43 by implanting center measurement. Of this cohort 431 patients
	(76.3%) had LVEF ≤ 30% and the remaining 177 patients (23.7%) had LVEF > 30%, including
	12.2% (n=74) with LVEF > 35%, reflecting the LVEF inclusion criterion of REVERSE. The
	mean center LVEF (26.7±7.0) did not differ from core lab LVEF (27.0±6.6). The distribution of
	LVEF measurements at

Table 1 . Baseline clinical characteristics divided by LVEF < 30% and > 30%.

 1

		LVEF < 30%	LVEF > 30%	p-value 1
		(n=431)	(n=177)
	Clinical Characteristics
	Age, yrs	61.8 ± 11.3	64.2 ± 10.0	0.01
	Gender, male n (%)	336 (78)	142 (80)	0.59
	Ischemic, n (%)	222 (52)	110 (62)	0.02
	Hypertension, n(%)	216 (50)	98 (55)	0.25
	Diabetic, n (%)	93 (22)	43 (24)	0.46
	ACE inhibitors or ARBs, n (%)	416 (97)	172 (97)	0.81
	Beta-blockers, n (%)	405 (94)	173 (98)	0.06
	Intrinsic QRS width (ms)	155.7 ± 22.2	147.3 ± 20.4	< 0.0001
	QRS morphology
	LBBB 2 , n (%)	266 (62)	102 (58)	0.31
	IVCD 2 , n (%)	127 (30)	54 (31)
	RBBB 2 , n (%)	35 (8)	21 (12)
	Glomerular filtration rate( ml/min)	87.6 ± 34.1	82.0 ± 30.3	0.048
	Supine systolic BP, mm Hg	122.9 ± 18.1	129.1 ± 19.8	0.0003
	Supine diastolic BP, mm Hg	71.7 ± 10.9	73.2 ± 11.8	0.16
	CRT-ICD implanted, n (%)	361 (84)	145 (82)	0.63
	1 p-values were calculated using a t-test (assuming unequal variances) for continuous variables and Fisher's exact test for categorical variables
	2 Sample sizes for QRS morphology are n=428 (LVEF < 30%) and n=177 (LVEF > 30%)

Table 2 . Baseline functional characteristics and echocardiographic data divided by LVEF <

 2

	30% and > 30%.
		LVEF < 30%	LVEF > 30%	p-value 1
		(n=431)	(n=177)
	Functional Characteristics
	NYHA class II, n (%)	369 (86)	133 (75)	0.003
	LVEF(center), %	25.0 ± 6.8	30.7 ± 5.9	< 0.0001
	LVEF (core) 2 , %	23.6 ± 4.1	35.1 ± 3.9	< 0.0001
	LVEDD 3 , cm	7.1 ± 0.9	6.5 ± 0.9	< 0.0001
	LVESD 3 , cm	6.0 ± 1.0	5.2 ± 1.0	< 0.0001
	LV mass 4 , g	276.7 ± 75.9	253.6 ± 75.9	0.01
	LVESVi 2 , ml/m 2	110.6 ± 37.6	74.5 ± 23.0	< 0.0001
	LVEDVi 2 , ml/m 2	143.8 ± 43.7	114.3 ± 33.0	< 0.0001
	MLHFQ 5 , (0-105)	28.6 ± 20.8	25.0 ± 20.0	0.06
	KCCQ 6 , (0-100)	71.8 ± 20.2	75.3 ± 19.3	0.06
	6-min hall walk 7 , m	390.8 ± 128.2	409.5 ± 124.3	0.10

1 p-values were calculated using a t-test (assuming unequal variances) for continuous variables and Fisher's exact test for categorical variables

[START_REF] Abraham | Multicenter InSync Randomized Clinical Evaluation. Cardiac resynchronization in chronic heart failure[END_REF]

Sample sizes for core lab LVEF, LVEDVi and LVESVi are n=399 (LVEF < 30%) and n=166 (LVEF > 30%)

Table 3 . Changes in functional and echocardiographic variables from the baseline visit to the 12 month follow-up divided by LVEF < 30% and > 30% at baseline.

 3

		LVEF < 30%		LVEF > 30%			Full study
		CRT OFF	CRT ON	p-value	CRT OFF	CRT ON	p-value CRT OFF	CRT ON	p-value 1
		(n=141)	(n=290)		(n=50)	(n=127)		(n=191)	(n=419)
	CCR
	% improved	43	57		30	48		40	54
	% unchanged	34	27	0.02	54	36	0.06	39	30	0.003
	% worsened	23	16		16	16		21	16
	NYHA class 2
	% improved	22	33.5		20	28		22	32
	% unchanged	64	56.5	0.055	72	59	0.31	66	57	0.04
	% worsened	14	10		8	13		12	11
	LVEF (core) 3 , %	2.5 ± 5.4	6.6 ± 9.2	< 0.0001 -3.8 ± 7.4	-0.1 ± 7.5	0.007	0.8 ± 6.6	4.6 ± 9.3	< 0.0001
	LVEDD 4 , cm	0.0 ± 0.6	-0.3 ± 0.8	0.002	-0.1 ± 0.7	-0.2 ± 0.7	0.63	-0.1 ± 0.6	-0.3 ± 0.8	0.005
	LVEDVi 3 , (ml/m 2 )	-0.5 ± 29.6	-22.9 ± 33.8 < 0.0001 -4.3 ± 22.9	-11.2 ± 27.0 0.12	-1.5 ± 27.9 -19.3 ± 32.2 < 0.0001
	LVESVi 3 , (ml/m 2 )	-2.9 ± 25.2	-23.5 ± 30.4 < 0.0001 2.1 ± 17.6	-6.7 ± 21.1	0.01	-1.6 ± 23.4 -18.3 ± 28.9 < 0.0001
	LV mass 5 , g	-10.9 ± 49.9 -14.3 ± 53.4 0.65	5.0 ± 42.4	-20.6 ± 50.5 0.04	-7.6 ± 48.6 -16.0 ± 52.6 0.19
	MLHFQ 6 , (0-105)	-7.4 ± 16.7	-9.0 ± 17.6	0.35	-4.7 ± 13.3	-6.7 ± 15.8	0.43	-6.7 ± 15.9 -8.4 ± 17.1	0.25

Table 4 . ANCOVA models for echocardiographic parameters to adjust for regression to the mean

 4

		LVEF < 30%	LVEF > 30%
		CRT ON -CRT OFF p-value	CRT ON -CRT OFF	p-value
	LVEF (core) 3 , %	4.4 ± 0.9	< 0.0001 3.7 ± 1.3	0.003
	LVEDD 4 , cm	-0.3 ± 0.1	0.003	-0.1 ± 0.2	0.63
	LVEDVi 3 , (ml/m 2 )	-22.7 ± 3.5	< 0.0001 -7.3 ± 4.3	0.09
	LVESVi 3 , (ml/m 2 )	-20.9 ± 3.2	< 0.0001 -9.0 ± 3.5	0.01
	LV stroke volume index, (ml/m 2 )	-1.4 ± 0.9	0.16	1.6 ± 1.7	0.33
	LV mass 5 , g	-7.1 ± 7.1	0.32	-26.6 ± 12.0	0.03

ACKNOWLEDGEMENTS

We would like to acknowledge Inge Kuippers, Verla Laager, Aimee Laechelt, and Lynn Landborg of Medtronic, Inc., CRDM Clinical Research for clinical study management, and Harrison Hudnall of Medtronic, Inc., CRDM Clinical Research for technical support of the manuscript.

FUNDING SOURCES

The REVERSE study was sponsored and funded by Medtronic, Inc., Minneapolis, MN. The study was designed and conducted in collaboration between physician experts and the Medtronic Clinical Research Department.

DISCLOSURES

Dr. Linde reports research grants, speaker honoraria, and consulting fees from Medtronic, and speaker honoraria and consulting fees from St. Jude Medical. Dr. Daubert reports speaker honoraria and consulting fees from Medtronic and St. Jude Medical. Dr. Abraham reports research grants, speaker honoraria, and consulting fees from Medtronic, St. Jude Medical, and Biotronik. Dr. St. John Sutton reports research grant support, speaker honoraria, and consulting fees from Medtronic as well as research support from Paracore. Dr. Ghio reports consulting fees from Medtronic. Dr Herre reports consulting fees from Medtronic and research grants from St Jude Medical, Boston Scientific and Medtronic. Dr. Bergemann is employed at Medtronic as a principal statistician. Dr. Gold reports consulting fees from Medtronic and Boston Scientific and lecture fees and research grants from Medtronic, Boston Scientific, and St. Jude Medical.


Christophe Blay

Dan Cristian Chiforeanu

Eveline Boucher

Florian Cabillic

Romain Desgrippes

Bérengère Leconte

Christophe Perrin

Sylvain Manfredi

Bernard Meunier

Dancristian Chiforeanu

Incidence of brain metastases in HER2+ gastric or gastroesophageal junction adenocarcinoma

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

To the editor, Gastric or gastroesophageal junction (GEJ) adenocarcinoma represents a major health issue, being the 3rd cause of death by cancer in the world. In industrialized countries, the incidence of GEJ cancers continues to rise, while gastric cancers have declined over the past few decades.

The human epidermal growth factor 2 (HER2) gene is a well-described proto-oncogene. HER2 gene amplification and protein overexpression have been mostly studied in breast cancer, where HER2 overexpression was reported in 15-20% of cases.

In breast cancer, HER2 overexpression is associated with a higher risk of brain metastases and significantly worse survival [START_REF] Altaha | Increased risk of brain metastases in patients with HER-2/neu-positive breast carcinoma[END_REF].

The prognostic value of HER2 overexpression in gastric and GEJ adenocarcinomas remains controversial. A recently published systematic review was inconclusive in patients after curative surgery [START_REF] Chua | Clinicopathologic factors associated with HER2-positive gastric cancer and its impact on survival outcomes--a systematic review[END_REF]. The standard of care in advanced gastric carcinoma patients has changed recently, with the results of the ToGa phase III trial adding trastuzumab to chemotherapy in patients with HER2 overexpression [START_REF] Bang | Trastuzumab in combination with chemotherapy versus chemotherapy alone for treatment of HER2-positive advanced gastric or gastro-oesophageal junction cancer (ToGA): a phase 3, open-label, randomised controlled trial[END_REF]. The study indicated that this subgroup of patients benefit from trastuzumab with a three months improvement of overall survival.

The aim of this study was to seek if the correlation between HER2 overexpression and brain metastases exists in gastric or GEJ adenocarcinomas, where brain metastases are uncommon.

Materials and methods

Patients

We collected retrospectively clinical and histological data on patients treated between 2007 and 2011 for metastatic gastric, GEJ or lower third esophageal adenocarcinoma from hospital medical charts of our institution. Data included location of the primary tumor, TNM staging, histological subtype, adjuvant chemotherapy and/or radiotherapy, time to recurrence, site of metastases, treatment of metastatic disease, occurrence of cerebral localization, chemotherapy regimens, response to treatment, time to tumor progression and overall survival. Immunohistochemistry IHC were assayed on 4 µm sections of formalin-fixed paraffin-embedded tumor tissues using primary polyclonal antibody A085 (Dako) using standard methodology. Cases were considered positive if scored 3+, negative if scored 0 to 1+, FISH was performed in cases scored 2+ by IHC [START_REF] Ruschoff | HER2 testing in gastric cancer: a practical approach[END_REF].

Fluorescent in situ hybridization

Interphase FISH analysis was performed on 4 µm sections of formalin-fixed paraffin-embedded tumor tissues using the PathVysion HER-2 DNA Probe Kit (Abbott Molecular, Rungis, France).

Cases were considered positive if the ratio HER2 (17q11.2-12) / CEP17 (17p11.1-q11.1 Alpha Satellite DNA) was superior to 2.2 [START_REF] Ruschoff | HER2 testing in gastric cancer: a practical approach[END_REF].

Statistical methodology

We compared the frequency of brain metastases from two groups, one HER2+ and the other HER2-, with Fisher's exact test. Survival analysis was performed by the Kaplan-Meier method for overall survival (OS) and progression-free survival (PFS).

Results

Between 2007 and 2011, 74 patients were treated for metastatic gastric or GEJ adenocarcinoma at our institution, and HER 2 status could be analyzed in 63. Eleven patients were excluded for missing histopathological data.

Demographic and clinical characteristics of patients are summarized in Table I.

Eleven (18%) specimens were HER2-positive (HER2+). Status were obtained by immunohistochemistry in 58 patients, FISH in 5. The median age was 62 years (range: 22-81), there were 52 men (83%) and 11 women (18%). Thirty-six patients (57%) had a gastric tumor, 27 (43%) tumor of the GEJ. After a median follow up of 9.4 months, 52 patients showed progression, and 38 patients died. All patients had chemotherapy either initially or at the time of metastatic evolution.

Median PFS was 5.3 months and median OS was 15.9 months. Thirty-eight patients (60%) had liver metastases, 32 (51%) lymph node metastases, 20 (32%) peritoneal carcinomatosis, 12 (19%) lung metastases and 3 (5%) brain metastases.

Two patients HER2+ did not receive trastuzumab because their treatment was performed before the result of the TOGA study. In the 11 patients HER2+, 3 (27%) had brain metastases, versus 0 (0%) in the 52 HER2-patients (Fisher's exact test p = 0.004). Brain metastases were all discovered after appearance of neurological symptoms (motor deficit, headache, and stroke). One occurred during treatment with trastuzumab. The control of brain metastases was obtained in all 3 patients with a multimodal treatment (surgery for one patient, radiotherapy for 3 patients and chemotherapy associated with trastuzumab for 3 patients). One of the patients was polymetastatic, and the other two had either lymph node or liver metastases. The response to treatment of brain lesions was heterogeneous with one partial response, and two stable disease. Moreover, peritoneal carcinomatosis was diagnosed in 20 of the 52 (39%) HER2-patients versus 0 of 11 (0%) HER2+ patients (p = 0.013). There was no association between HER2 status and other sites of metastases, and no association between brain or peritoneal carcinomatosis and other factors (gender, age, T and N stage).

We studied PFS and OS as an exploratory analysis, due to small numbers. PFS was significantly better among HER2 + patients treated with trastuzumab than in patients with HER2-: median 9.4 months against 5.0 months (p = 0.041) (Figure 1). The respective median OS was not reached and 10.9 months, but the difference was not statistically significant (p = 0.057) (Figure 1).

Discussion

The prognostic value of HER2 gene amplification and protein overexpression in gastric adenocarcinoma is not as clear as in breast cancer. The largest study to date with 900 cases found that HER2 expression in gastric cancer was not correlated to prognosis. In this study less than 10% of all gastric cancer expressed HER2 [START_REF] Grabsch | HER2 expression in gastric cancer: Rare, heterogeneous and of no prognostic value -conclusions from 924 cases of two independent series[END_REF]. In a review of the 35 studies reporting the impact of HER2 overexpression on survival, 44% of patients had TNM stage I/II, and 56% had TNM stage III/IV disease. Twenty studies (57%) reported no difference in overall survival, two studies (6%) reported significantly longer overall survival in patients with HER2 overexpression and 13 studies (37%) reported significantly poorer overall survival in patients with HER2 overexpression [START_REF] Chua | Clinicopathologic factors associated with HER2-positive gastric cancer and its impact on survival outcomes--a systematic review[END_REF]. Overall it appears difficult to determine to the prognostic value of HER2 overexpression.

In breast cancer, HER2+ patients had an increased risk of brain metastases [START_REF] Minisini | Risk factors and survival outcomes in patients with brain metastases from breast cancer[END_REF][START_REF] Ahn | Clinical implication of Time To Brain Metastasis (TTBM) according to breast cancer subtypes[END_REF], and the development of central nervous system (CNS) metastases in breast cancer is associated with poor prognosis [START_REF] Minisini | Risk factors and survival outcomes in patients with brain metastases from breast cancer[END_REF]. However, to date similar data on HER2+ gastric adenocarcinoma and brain metastases are still lacking. In this retrospective single-center series, we tried to offer some preliminary data. We showed increased incidence of brain metastases in patients with HER2+ gastric or GEJ adenocarcinomas. Three HER2+ patients had cerebral metastases, as compared with HER2-(p = 0.004). Another previously unreported finding of this study is the less frequent peritoneal carcinomatosis in the HER2+ group. This could be related to the fact that HER2 overexpression is less frequent for diffuse type gastric cancer [START_REF] Chua | Clinicopathologic factors associated with HER2-positive gastric cancer and its impact on survival outcomes--a systematic review[END_REF]. Diffuse-type gastric cancer have been associated with more frequent peritoneal carcinomatosis. These differences in pattern of metastases are probably under the dependence of different biological behavioral, which may gain importance in the next years for decision-making.

Limits of our study are clearly its monocentric nature and the small number of patients. Our results should be replicated by other group. However, in the current study, all histological specimens were assessed for HER2 status as recommended by Rüschoff et al, with initial IHC testing and FISH/silver in situ hybridization to re-evaluate samples with an IHC score of +2 [START_REF] Ruschoff | HER2 testing in gastric cancer: a practical approach[END_REF].

In conclusion, in this single-center retrospective study, we showed an increased incidence of brain metastases in patients with HER2 + gastric or GEJ adenocarcinomas, and a decreased incidence of peritoneal carcinomatosis. The prognosis of patients HER2 + treated with trastuzumab seems better than that of patients HER2-. These results should be confirmed in a multicenter study. The possible consequence in this population would be the necessity of a systematic search for brain metastases.

Conflicts of interest: none to declare

Figure 1 :

 1 Figure 1: Progression-free survival (A) and overall survival (B) for patients treated with and without trastuzumab