Usefulness of a novel "response score" to predict hemodynamic and clinical outcome from cardiac resynchronization therapy

Risk scores in cardiac resynchronization therapy-A review of the literature

Cardiac resynchronization therapy (CRT) for selected heart failure (HF) patients improves symptoms and reduces morbidity and mortality; however, the prognosis of HF is still poor. There is an emerging need for tools that might help in optimal patient selection and provide prognostic information for patients and their families. Several risk scores have been created in recent years; although, no literature review is available that would list the possible scores for the clinicians. We identified forty-eight risk scores in CRT and provided the calculation methods and formulas in a ready-to-use format. The reviewed score systems can predict the prognosis of CRT patients; some of them have even provided an online calculation tool. Significant heterogeneity is present between the various risk scores in terms of the variables incorporated and some variables are not yet used in daily clinical practice. The lack of cross-validation of the risk scores limits their routine use and objective selection. As the number of prognostic markers of CRT is overwhelming, further studies might be required to analyze and cross-validate the data.

Coronary Sinus Lead Positioning

Although cardiac resynchronization therapy improves morbidity and mortality in patients with cardiomyopathy, heart failure, and electrical dyssynchrony, the rate of nonresponders using standard indications and implant techniques is still high. Optimal coronary sinus lead positioning is important to increase the chance of successful resynchronization. Patient factors such as cause of heart failure, type of dyssynchrony, scar burden, coronary sinus anatomy, and phrenic nerve capture may affect the efficacy of the therapy. Several modalities are under investigation. Alternative left ventricular lead implantation strategies are occasionally required when the transvenous route is not feasible or would result in a suboptimal lead position.

Coronary Sinus Lead Positioning

Although cardiac resynchronization therapy improves morbidity and mortality in patients with cardiomyopathy, heart failure, and electrical dyssynchrony, the rate of nonresponders using standard indications and implant techniques is still high. Optimal coronary sinus lead positioning is important to increase the chance of successful resynchronization. Patient factors such as cause of heart failure, type of dyssynchrony, scar burden, coronary sinus anatomy, and phrenic nerve capture may affect the efficacy of the therapy. Several modalities are under investigation. Alternative left ventricular lead implantation strategies are occasionally required when the transvenous route is not feasible or would result in a suboptimal lead position.

Circulating MicroRNA-30d Is Associated With Response to Cardiac Resynchronization Therapy in Heart Failure and Regulates Cardiomyocyte Apoptosis: A Translational Pilot Study

BACKGROUND

Biomarkers that predict response to cardiac resynchronization therapy (CRT) in heart failure patients with dyssynchrony (HFDYS) would be clinically important. Circulating extracellular microRNAs (miRNAs) have emerged as novel biomarkers that may also play important functional roles, but their relevance as markers for CRT response has not been examined.

METHODS AND RESULTS

Comprehensive miRNA polymerase chain reaction arrays were used to assess baseline levels of 766 plasma miRNAs in patients undergoing clinically indicated CRT in an initial discovery set (n=12) with and without subsequent echocardiographic improvement at 6 months after CRT. Validation of candidate miRNAs in 61 additional patients confirmed that baseline plasma miR-30d was associated with CRT response (defined as an increase in left ventricular ejection fraction ≥10%). MiR-30d was enriched in coronary sinus blood and increased in late-contracting myocardium in a canine model of HFDYS, indicating cardiac origin with maximal expression in areas of high mechanical stress. We examined the functional effects of miR-30d in cultured cardiomyocytes and determined that miR-30d is expressed in cardiomyocytes and released in vesicles in response to mechanical stress. Overexpression of miR-30d in cultured cardiomyocytes led to cardiomyocyte growth and protected against apoptosis by targeting the mitogen-associated kinase 4, a downstream effector of tumor necrosis factor. In HFDYS patients, miR-30d plasma levels inversely correlated with high-sensitivity troponin T, a marker of myocardial necrosis.

CONCLUSIONS

Baseline plasma miR-30d level is associated with response to CRT in HFDYS in this translational pilot study. MiR-30d increase in cardiomyocytes correlates with areas of increased wall stress in HFDYS and is protective against deleterious tumor necrosis factor signaling.

A new baseline scoring system may help to predict response to cardiac resynchronization therapy

INTRODUCTION

The PROSPECT trial reported no single echocardiographic measurement of dyssynchrony is recommended to improve patient selection for cardiac resynchronization therapy (CRT).

MATERIAL AND METHODS

In 100 consecutive patients who received CRT, we analyzed 27 ECG and echocardiographic variables to predict a positive response to CRT defined as a left ventricular (LV) end systolic volume decrease of ≥ 15% after CRT.

RESULTS

Right ventricular (RV) pacing-induced left bundle branch block (LBBB), time difference between LV ejection measured by tissue Doppler and pulsed wave Doppler (T(TDI-PW)), and wall motion score index (WMSI) were significantly associated with positive CRT response by multivariate regression. We assigned 1 point for RV pacing-induced LBBB, 1 point for WMSI ≤ 1.59, and 2 points for T(TDI-PW) > 50 ms. Overall mean response score was 1.79 ±1.39. Cutoff point for response score to predict positive response to CRT was > 2 by receiver operating characteristic (ROC) analysis. Area under ROC curve was 0.97 (p = 0.0001). Cardiac resynchronization therapy responders in patients with response score > 2 and ≤ 2 were 36/38 (95%) and 7/62 (11%, p < 0.001), respectively. After age and gender adjustment, the response score was related to CRT response (OR = 45.4, p < 0.0001).

CONCLUSIONS

A response score generated from clinical, ECG and echocardiographic variables may be a useful predictor for CRT response. However, this needs to be validated.

A patient selection score for cardiac resynchronization therapy

BACKGROUND

We hypothesized a patient selection score (PSS) may improve patient selection for cardiac resynchronization therapy (CRT).

METHODS

Of 136 patients who received CRT, group A included 100 study patients and group B 36 patients for validation. A positive response to CRT was a left ventricular (LV) end-systolic volume decrease of ≥15% and survival from heart failure at end of follow-up.

RESULTS

Of 100 group A patients, 37 (37%) were CRT responders during 14-month follow-up. A 7-point PSS was generated based on six variables. The cutoff point for PSS to predict a positive response to CRT was >4 by receiver operating characteristic (ROC) analysis. The area under the ROC curve (AUC) for PSS to predict CRT response was 0.94 (P = 0.0001). CRT responders in patients with a PSS > 4 and ≤4 were 33/40 (83%), and 4/60 (7%), respectively (P < 0.001). Multivariate Cox proportional regression analysis showed that PSS was related to CRT response (hazard ratio = 10.3, P < 0.0001). The CRT response rate in patients with a PSS > 4 in Group B was also significantly higher compared to a PSS ≤ 4 (88% vs. 16%, P < 0.001). The AUC for PSS to predict a CRT response in Group B was 0.91 (P = 0.0001).

CONCLUSIONS

Patients with a PSS >4 are the most likely to respond to CRT. Using this score system, a PSS score >4 can predict the probability of a CRT response up to 88% in patients with heart failure and a wide QRS duration.

Maximum derivative of left ventricular pressure predicts cardiac mortality after cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) has been reported to improve cardiac performance. However, CRT in patients with advanced heart failure is not always accompanied by an improvement in survival rates. We investigated the association between hemodynamic studies and long-term prognosis after CRT.

METHODS

A total of 68 consecutive patients receiving CRT devices due to advanced heart failure were assessed by hemodynamic study and long-term outcome after implantation of the device. Hemodynamic parameters were measured both with the CRT on and off.

RESULTS

Patients demonstrated significant improvement in the maximum first derivative of left ventricular (LV) pressure (LV dP/dt(max) ) and QRS duration after periods with the CRT on. During the follow-up period of 34.9 ± 17.6 months, basal LV dP/dt(max) and isovolemic LV pressure half-time (T½), but not percent change in LV dP/dt(max) , were independent predictors of cardiac mortality or hospitalization due to heart failure after multivariate Cox regression analysis. The Kaplan-Meier survival analysis revealed that patients in the lowest basal LV dP/dt(max) tertile or the longest basal T½ tertile exhibited a significantly higher cardiac-caused mortality or heart failure hospitalization.

CONCLUSIONS

Lower LV dP/dt(max) or longer T½ independently predicts cardiac mortality or heart failure hospitalization in patients receiving CRT. The assessment of the basal LV dP/dt(max) and T½ could provide useful information in long-term prognosis after CRT.

Novedades en estimulación cardiaca 2006

This article summarizes progress in cardiac pacing that has taken place in the last year, such as the incorporation of navigation technology into programmers, systems for monitoring hemodynamic parameters, and new developments in patient follow-up, principally home monitoring and the use of treatment guidelines. In addition, the article covers recent findings in resynchronization therapy, paroxysmal atrial fibrillation, and the management of patients with pacemakers who need to undergo magnetic resonance imaging.