An interventional study of NICaS guided CRT optimization in Congestive Heart Failure, sponsored by Sheba Medical Center. Completed at 1 site in Israel. Open to participants aged 18 Years to 90 Years. Per ClinicalTrials.gov, last updated 2015-08-06.
Sponsored by Sheba Medical Center · Not applicable, Interventional, and Treatment
This proposal aims to evaluate the added clinical and echocardiographic benefit of using the non-invasive impedance-based cardiac output measurement system (NICaS) for optimizing atrio-ventricular and inter-ventricular delays in chronic (more than 6 months) CRT recipients.
Introduction
Cardiac resynchronization therapy (CRT) is an efficient treatment in heart failure (HF) patients with left ventricular (LV) systolic dysfunction and wide QRS. It is associated with improved exercise capacity, quality of life and left ventricular ejection fraction, as well as reverse remodeling, mitral regurgitation reduction, and mortality reduction.
Predicting response to CRT is important as 30% of patients have no or minimal clinical improvement following CRT. Several parameters have been shown to influence response following implantation. Some relate to patients' characteristics including underlying heart disease, comorbidities and arrhythmias, type and severity of conduction disorder, presence and degree of dyssynchrony, presence and extent of scar tissue and functional myocardial reserve. Others are associated with technical aspects, including electrical and anatomical positioning of LV lead, programming mode and percentage of effective bi-ventricular pacing.
Optimization of the atrio-ventricular (AV) delay and inter-ventricular (VV) delays can be used for maximizing CRT benefit, but is not routinely recommended by current guidelines. Standard optimization is performed under echocardiography guidance - a time and resource consuming method. Other non-invasive methods, such as impedance cardiography, can be used for AV delay optimization.
Rationale for CRT optimization using NICaS
The non-invasive cardiac system (NICaS) is a whole-body bioimpedance measurement method allowing real-time cardiac output (CO) assessment. It has been FDA approved for assisting in the diagnosis, monitoring and care management of patients with congestive heart failure as well as for cardiac pacemaker optimization. Clinical trials have shown its utility for the follow-up of outpatient monitoring chronic heart failure, for monitoring patients with heart failure and pulmonary hypertension.
NICaS is sensitive enough for detecting real-time small changes in CO. Based on NICaS measured CO changes following AV and VV delays modifications, small series support its use for CRT optimization in a clinical setting, suggesting it may be associated with a reduction in non-responder rate.
Hypothesis
We hypothesize that the use of NICaS for optimization of AV and VV delays in chronic (more than 6 months) CRT recipients may result in an added clinical and echocardiographic benefit.
Specific Aims
I. At Inclusion
I.A. Baseline assessment. Patients included in the study will benefit from the following at baseline assessment, performed in an outpatient setting:
Clinical evaluation:
I.B. NICaS protocol for optimal AV and VV delays assessment. After baseline assessment is completed, patients will benefit from NICaS hemodynamic assessment and CRT programming according to NICaS guided optimal AV and VV delays. (for NICaS protocol for optimal AV and VV delays measurements - see Interventions)
I.C. After NICaS guided CRT programming, patients will perform a 6MWT
II. At 6 months follow-up. At 6 months, patients will benefit from the following evaluations:
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This study's enrollment of 42 is below the median of 72 across 3,736 interventional studies indexed under Heart Failure.
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Exclusion Criteria:
For each subject, we will determine a set of AV and VV delays values, for which the NICaS measured CO will be maximum. In each patient, the CRT device will then be programmed according to these values.
Other: NICaS guided CRT optimization
1. Baseline CO measurement by NICaS 2. AV delay optimization: 1. AV delay will be changed (increase and decrease) by 30 ms steps , and for each new AV value, the CO will be real-time measured by NICaS 2. The AV delay yielding the maximal CO, will be considered the optimal AV delay 3. The device will be programmed using the optimal AV delay 3. VV delay optimization: 1. After Step 2, the baseline VV delay will be changed (increase and decrease; meaning that we will be pacing alternatively the LV before the RV, then the RV before the LV), by 30 ms steps, and for each new VV value, the CO will be real-time measured by NICaS 2. The VV delay yielding the maximal CO, will be considered the optimal VV delay 3. The device will be programmed using the optimal VV delay
Predictors for significant cardiac output improvement
Using logistic regression, we will look for predictors (clinical, ECG, echocardiographic, hemodynamic) of significant (at least 20%) acute cardiac output improvement (as assessed by NICaS), after NICaS guided AV and VV delays optimization.
Time frame: Within the first year after beginning of study
Acute six-minute walk test changes after NICaS optimization
After NICaS guided AV and VV delays optimization, each patient will perform a six-minute walk test, which will be compared to the baseline (before NICaS optimization) six-minute walk test. A 10% change will be considered significant.
Time frame: Within the first 24 hours after enrollment
Reverse remodeling
Each patient will undergo routinely a 6-month echocardiography which will be compared to the baseline (inclusion day) echocardiography. A relative reduction of 10% of the left ventricular end-systolic volume will be considered as positive reverse remodeling.
Time frame: At 6 months after enrollment
Hospitalization rate for heart failure
Hospitalization rate for acute heart failure during the first 6 months following NICaS guided CRT optimization
Time frame: Within the first 6 months after enrollment
Supraventricular arrhythmia occurrence
CRT device measurement of the total time spent in auto-mode switch during the first 6 months following NICaS guided CRT optimization, and comparison to the 6 months prior to the optimization.
Time frame: At 6 months after enrollment
Clinical improvement
Clinical improvement at 6 months after CRT optimization will be assessed using a composite score combining NYHA class, QoL and the 6MWT. Each will be classified as improved (+1), stable (0) or worsened (-1) and the three components will be summed. The patient will be considered improved if he will have had ≥1 class reduction in his NYHA class, worsened if he will have had ≥1 class increase and unchanged if he will have had no change in his baseline NYHA class. Similar definitions will be used for absolute variation (improvement or deterioration) of 10 points in QoL, or relative 10%change in six-minute walk distance. A clinical improvement will be considered in the presence of a summed score ≥+1 without death during the first 6 months of follow-up after CRT optimization.
Time frame: At 6 months after enrollment
This study is completed, as verified in Aug 2015. You cannot join it, but the record below documents what was studied.
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