Influence of diabetes on left ventricular systolic and diastolic function and on long-term outcome after cardiac resynchronization therapy

What Have We Learned in the Last 20 Years About CRT Non-Responders?

Although cardiac resynchronization therapy (CRT) has become well established in the treatment of heart failure, the management of patients who do not respond after CRT remains a key challenge. This review will summarize what we have learned about non-responders over the last 20 years and discuss methods for optimizing response, including the introduction of novel therapies.

Reverse Cardiac Remodeling Following Initiation of Sacubitril/Valsartan in Patients With Heart Failure With and Without Diabetes

OBJECTIVE

This study sought to determine whether patients with heart failure and reduced ejection fraction (HFrEF) with type 2 diabetes mellitus (T2DM) have similar reverse cardiac remodeling with sacubitril/valsartan as patients without T2DM.

BACKGROUND

Sacubitril/valsartan promotes reverse cardiac remodeling and improves outcomes in patients with HFrEF. Patients with HFrEF with T2DM have worse prognosis than those without T2DM.

METHODS

In this post hoc analysis of PROVE-HF (Prospective Study of Biomarkers, Symptom Improvement, and Ventricular Remodeling During Sacubitril/Valsartan Therapy for Heart Failure), we examined changes in N-terminal pro-b-type natriuretic peptide (NT-proBNP), measures of cardiac remodeling, and Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS) scores from baseline to 12 months following initiation of sacubitril/valsartan between patients with HFrEF with and without T2DM. Using latent growth curve modeling, we evaluated the longitudinal association between changes in NT-proBNP, left ventricular ejection fraction, and KCCQ-OS.

RESULTS

Among 794 patients enrolled, 361 (45.5%) had T2DM. NT-proBNP concentrations were modestly higher at baseline among patients with T2DM but were reduced after initiation of sacubitril/valsartan. Cross-sectional improvement was observed in left ventricular ejection fraction (T2DM: 28.3% at baseline and 37% at 12 months vs. non-T2DM: 28.1% at baseline and 38.3% at 12 months) and KCCQ-OS (T2DM: 71 at baseline and 83 at 12 months vs. non-T2DM: 76 at baseline and 88 at 12 months). Similar changes were also observed for other echocardiographic measures. In longitudinal analyses, the average NT-proBNP change was similar in patients with T2DM (-5.6% vs. -7.1% per 90-day interval; p = 0.64), whereas improvements in KCCQ-OS scores were slightly smaller (2.1 vs. 3.46 per 90-day interval; p = 0.07).

CONCLUSIONS

Sacubitril/valsartan favorably affects natriuretic peptide levels, reverse cardiac remodeling, and health status in patients with HFrEF with and without T2DM. (Effects of Sacubitril/Valsartan Therapy on Biomarkers, Myocardial Remodeling and Outcomes [PROVE-HF]; NCT02887183).

Differential effect of cardiac resynchronization therapy in patients with diabetes mellitus: a long-term retrospective cohort study

AIMS

Cardiac resynchronization therapy (CRT) has become an important therapy in patients with heart failure with reduced left ventricular ejection fraction (LVEF). The effect of diabetes on long-term outcome in these patients is controversial. We assessed the effect of diabetes on long-term outcome in CRT patients and investigated the role of diabetes in ischaemic and non-ischaemic cardiomyopathy.

METHODS AND RESULTS

All patients undergoing CRT implantation at our institution between November 2000 and January 2015 were enrolled. The study endpoints were (i) a composite of ventricular assist device (VAD) implantation, heart transplantation, or all-cause mortality; and (ii) reverse remodelling (improvement of LVEF ≥ 10% or reduction of left ventricular end-systolic volume ≥ 15%). Median follow-up of the 418 patients (age 64.6 ± 11.6 years, 22.5% female, 25.1% diabetes) was 4.8 years [inter-quartile range: 2.8;7.4]. Diabetic patients had an increased risk to reach the composite endpoint [adjusted hazard ratio (aHR) 1.48 [95% CI 1.12-2.16], P = 0.041]. Other factors associated with an increased risk to reach the composite endpoint were a lower body mass index or baseline LVEF (aHR 0.95 [0.91; 0.98] and 0.97 [0.95; 0.99], P < 0.01 each), and a higher New York Heart Association functional class or creatinine level (aHR 2.14 [1.38; 3.30] and 1.04 [1.01; 1.05], P < 0.05 each). Early response to CRT, defined as LVEF improvement ≥ 10%, was associated with a lower risk to reach the composite endpoint (aHR 0.60 [0.40; 0.89], P = 0.011). Reverse remodelling did not differ between diabetic and non-diabetic patients with respect to LVEF improvement ≥ 10% (aHR 0.60 [0.32; 1.14], P = 0.118). However, diabetes was associated with decreased reverse remodelling with respect to a reduction of left ventricular end-systolic volume ≥ 15% (aHR 0.45 [0.21; 0.97], P = 0.043). In patients with ischaemic cardiomyopathy, survival rates were not significantly different between diabetic and non-diabetic patients (HR 1.28 [0.83-1.97], P = 0.101), whereas in patients with non-ischaemic cardiomyopathy, diabetic patients had a higher risk of reaching the composite endpoint (HR 1.65 [1.06-2.58], P = 0.027). The latter effect was dependent on other risk factors (aHR 1.47 [0.83-2.61], P = 0.451). The risk of insulin-dependent patients was not significantly higher than in patients under oral antidiabetic drugs (HR 1.55 [95% CI 0.92-2.61], P = 0.102).

CONCLUSIONS

Long-term follow-up revealed diabetes mellitus as independent risk factor for all-cause mortality, heart transplantation, or VAD in heart failure patients undergoing CRT. The detrimental effect of diabetes appeared to weigh heavier in patients with non-ischaemic compared with ischaemic cardiomyopathy.

Distinct Myocardial Targets for Diabetes Therapy in Heart Failure With Preserved or Reduced Ejection Fraction

Noncardiac comorbidities such as diabetes mellitus (DM) have different outcomes in heart failure with preserved ejection fraction (HFpEF) compared with heart failure with reduced ejection fraction (HFrEF). These different outcomes are the result of distinct myocardial effects of DM on HFpEF and HFrEF, which relate to different mechanisms driving myocardial remodeling in each heart failure phenotype. Myocardial remodeling is driven by microvascular endothelial inflammation in HFpEF and by cardiomyocyte cell death in HFrEF. Evidence consists of: different biomarker profiles, in which inflammatory markers are prominent in HFpEF and markers of myocardial injury or wall stress are prominent in HFrEF; reduced coronary flow reserve with microvascular rarefaction in HFpEF; and upregulation of free radical-producing enzymes in endothelial cells in HFpEF and in cardiomyocytes in HFrEF. As biopsies from patients with diabetic cardiomyopathy reveal, DM affects failing myocardium by phenotype-specific mechanisms. In HFpEF, DM mainly increases cardiomyocyte hypertrophy and stiffness, probably because of hyperinsulinemia and microvascular endothelial inflammation. In HFrEF, DM augments replacement fibrosis because of cardiomyocyte cell death induced by lipotoxicity or advanced glycation end products. Because DM exerts distinct effects on myocardial remodeling in HFpEF and HFrEF, the heart failure phenotype is important for DM therapy.

Effect of Diabetes Mellitus on Cardiac Resynchronization Therapy and to Prognosis in Heart Failure (from the Prospective Evaluation of Asian With Cardiac Resynchronization Therapy for Heart Failure Study)

The association of diabetes mellitus (DM) with cardiac resynchronization therapy (CRT) response and cardiovascular outcomes in Asian patients with heart failure (HF) is unclear. This study aims to investigate the effects of DM on CRT response and cardiovascular outcomes in Asian HF patients. Consecutive Asian HF patients receiving CRT were enrolled in the Prospective Evaluation of Asian with CRT for Heart Failure (PEACH) study from 2011 to 2017. CRT response and super-response were defined as decrease in end-systolic volume index ≥15% and ≥30%, respectively. Primary endpoint was time to composite of HF-hospitalization and all-cause mortality. Among 161 patients followed for 3.3 ± 1.5 years (age 66.7 ± 11.2 years, 22% females, mean QRS duration 154.3 ± 22.4 ms, 83% left bundle branch block), 84 (52%) were CRT responders and 57 (35%) were super-responders. Of 82 (51%) patients with DM (100% type 2, mean HbA1c 7.3 ± 1.9%), 35 (43%) were responders. DM attenuated reverse remodeling (CRT response: AOR 0.44, 95% confidence interval [CI] 0.20 to 0.98, p < 0.05; super-response: AOR 0.42, 95% CI 0.18 to 0.97, p <0.05), and DM increased HF-hospitalization and all-cause mortality (AHR 1.68, 95% CI 1.00 to 2.82, p = 0.05). The extent of CRT-response correlates with higher event-free survival (CRT response: AHR 0.5, 95% CI 0.30 to 0.81, p = 0.005; super-response: AHR 0.27, 95% CI 0.14 to 0.52, p < 0.001). In conclusion, the extent of reverse remodeling post-CRT is the strongest predictor of event free survival. However, DM is detrimental to the CRT recipient by attenuating reverse remodeling, inducing end organ dysfunction and is independently associated with worsened clinical outcomes among Asian HF patients.

Left ventricular reverse remodelling predicts long-term outcomes in patients with functional mitral regurgitation undergoing MitraClip therapy: results from a multicentre registry

AIMS

To explore whether left ventricular reverse remodelling (LVRR) is a predictor of outcomes in patients with functional mitral regurgitation (FMR) undergoing MitraClip procedure.

METHODS AND RESULTS

We analysed 184 consecutive patients with FMR who underwent successful MitraClip procedure. LVRR was defined as a reduction in left ventricular end-systolic volume ≥ 10% from baseline to 6 months. LVRR was observed in 79 (42.9%) patients. Compared with non-LVRR, LVRR patients were more likely to be females, less likely to have an ischaemic aetiology of mitral regurgitation or a prior (<6 months) heart failure (HF) hospitalization, and had smaller left ventricular dimensions. New York Heart Association class improved from baseline up to 1-year follow-up in both groups. Higher rates of overall survival (87.3% vs. 75.2%, P = 0.039), freedom from HF hospitalization (77.2% vs. 60%, P = 0.020), and freedom from the composite endpoint (cardiovascular mortality or HF hospitalization) (74.7% vs. 55.2%; P = 0.012) were observed in LVRR vs. non-LVRR patients at 2-year follow-up. LVRR was associated with a significant reduction of the adjusted relative risk of mortality, HF hospitalization and composite endpoint [hazard ratio (HR) 0.44; 95% confidence interval (CI) 0.20-0.96, P = 0.040; HR 0.55; 95% CI 0.32-0.97, P = 0.038; and HR 0.54; 95% CI 0.32-0.92, P = 0.023, respectively]. Female gender, absence of diabetes, freedom from prior HF hospitalization, non-ischaemic aetiology of mitral regurgitation, and left ventricular end-diastolic diameter < 75 mm were found to be independent predictors of LVRR.

CONCLUSIONS

Left ventricular reverse remodelling is associated with better long-term outcomes in patients with FMR successfully treated with MitraClip. A careful patient selection may be useful as specific baseline features predict favourable left ventricular remodelling. [Correction added on 17 January 2019, after online publication: the preceding sentence has been changed.].

Usefulness of the CRT-SCORE for Shared Decision Making in Cardiac Resynchronization Therapy in Patients With a Left Ventricular Ejection Fraction of ≤35

Individualized estimation of prognosis after cardiac resynchronization therapy (CRT) remains challenging. Our aim was to develop a multiparametric prognostic risk score (CRT-SCORE) that could be used for patient-specific clinical shared decision making about CRT implantation. The CRT-SCORE was derived from an ongoing CRT registry, including 1,053 consecutive patients (age 67 ± 10 years, 76% male). Using preimplantation variables, 100 multiple imputed datasets were generated for model calibration. Based on multivariate Cox regression models, cross-validated linear prognostic scores were calculated, as well as survival fractions at 1 and 5 years. Specifically, the CRT-SCORE was calculated using atrioventricular junction ablation, age, gender, etiology, New York Heart Association class, diabetes, hemoglobin level, renal function, left bundle branch block, QRS duration, atrial fibrillation, left ventricular systolic and diastolic functions, and mitral regurgitation, and showed a good discriminative ability (areas under the curve 0.773 at 1 year and 0.748 at 5 years). During the long-term follow-up (median 60 months, interquartile range 31 to 85), all-cause mortality was observed in 494 (47%) patients. Based on the distribution of the CRT-SCORE, lower- and higher-risk patient groups were identified. Estimated mean survival rates of 98% at 1 year and 92% at 5 years were observed in the lowest 5% risk group (L5 CRT-SCORE: -4.42 to -1.60), whereas the highest 5% risk group (H5 CRT-SCORE: 1.44 to 2.89) showed poor survival rates: 78% at 1 year and 22% at 5 years. In conclusion, the CRT-SCORE allows accurate prediction of 1- and 5-year survival rates after CRT using readily available and CRT-specific clinical, electrocardiographic, and echocardiographic parameters. The model may assist clinicians in counseling patients and in decision making.

Multiple Comorbidities and Response to Cardiac Resynchronization Therapy: MADIT-CRT Long-Term Follow-Up

BACKGROUND

Data regarding cardiac resynchronization therapy (CRT) in patients with multiple comorbidities are limited.

OBJECTIVES

This study evaluated the association of multiple comorbidities with the benefits of CRT over implantable cardioverter-defibrillator (ICD) alone.

METHODS

We examined 1,214 MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy) study patients with left bundle branch block (LBBB) and 0, 1, 2, or ≥3 comorbidities, including renal dysfunction, hypertension (HTN), diabetes, coronary artery disease, history of atrial arrhythmias, history of ventricular arrhythmias, current smoking, and cerebrovascular accident. In an adjusted analysis, we analyzed risk of heart failure (HF) events or death by comorbidity group in all patients and in patients with CRT with defibrillator (CRT-D) versus ICD. Then we examined percent change in left ventricular (LV) end-diastolic volume, LV end-systolic volume, LV ejection fraction, left atrial volume, and LV dyssynchrony at 1-year in CRT-D patients by comorbidity group.

RESULTS

There was an inverse relationship between comorbidity burden and improvements in LV end-systolic volume, LV end-diastolic volume, left ventricular ejection fraction, left atrial volume, and LV dyssynchrony. In an adjusted model, there was an increasing risk of death or nonfatal HF events with increasing comorbidity burden regardless of treatment group (p < 0.001). During a mean follow-up of 4.65 years, there was no interaction with respect to comorbidity burden and the benefit of CRT-D versus ICD only for death or nonfatal HF events (interaction p = 0.943). In the groups with greatest comorbidity burden (2 and ≥3), the absolute risk reduction associated with CRT-D over ICD alone appeared greater than that seen for groups with less comorbidity burden (0 and 1).

CONCLUSIONS

During long-term follow-up of MADIT-CRT study patients with LBBB randomized to CRT-D, there were differences in HF or death risk and in the degree of reverse remodeling among comorbidity groups. However, the burden of comorbidity does not appear to compromise the clinical benefits of CRT-D compared with ICD alone.

Effects of AMPD1 gene C34T polymorphism on cardiac index, blood pressure and prognosis in patients with cardiovascular diseases: a meta-analysis

Background

The meta-analysis was aimed to evaluate the effects of AMPD1 gene C34T polymorphism on cardiac function indexes, blood pressure and prognosis in patients with cardiovascular diseases (CVD).

Methods

Eligible studies were retrieved through a comprehensive search of electronic databases and manual search. Then the high-quality studies met the rigorous inclusion and exclusion criteria, as well as related to the subject was selected for the study. Comprehensive data analyses were conducted using STATA software 12.0.

Results

The study results revealed that CVD patients with CT + TT genotype of AMPD1 C34T polymorphism presented elevated left ventricular ejection fraction (LVEF) (%) and reduced left ventricular end diastolic dimension (LVEDD) (mm) as compared with CC genotype, moreover, the subgroup analysis found that the LVEF (%) was markedly higher in heart failure (HF) patients carrying CT + TT genotype than CC genotype. Besides, the systolic blood pressure (SBP) (mmHg) in CVD patients with CT + TT genotype was obviously decreased in contrast with the CC genotype. Patients suffered from HF with different genotypes (CT + TT and CC) of AMPD1 C34T polymorphism exhibited no significant differences in total survival rate and cardiac survival rate.

Conclusions

Our current meta-analysis indicated that the T allele of AMPD1 gene C34T polymorphism may be correlated with LVEF, LVEDD and SBP, which plays a protective role in the cardiac functions and blood pressure in CVD patients, but had no effects on total survival rate and cardiac survival rate for HF.

Impact of baseline renal function on all-cause mortality in patients who underwent cardiac resynchronization therapy: A systematic review and meta-analysis

BACKGROUND

Cardiac resynchronization therapy (CRT) improves both morbidity and mortality in selected patients with heart failure and increased QRS duration. However, chronic kidney disease (CKD) may have an adverse effect on patient outcome. The aim of this systematic review was to analyze the existing data regarding the impact of baseline renal function on all-cause mortality in patients who underwent CRT.

METHODS

Medline database was searched systematically, and studies evaluating the effect of baseline renal function on all-cause mortality in patients who underwent CRT were retrieved. We performed three separate analyses according to the comparison groups included in each study. Data were analyzed using Review Manager software (RevMan version 5.3; Oxford, UK).

RESULTS

We included 16 relevant studies in our analysis. Specifically, 13 studies showed a statistically significant higher risk of all-cause mortality in patients with impaired baseline renal function who underwent CRT. The remaining three studies did not show a statistically significant result. The quantitative synthesis of five studies showed a 19% decrease in all-cause mortality per 10-unit increment in estimated glomerular filtration rate (eGFR) [HR: 0.81, 95% CI (0.73-0.90), p<0.01, 86% I²]. Additionally, we demonstrated that patients with an eGFR<60 mL/min/1.73 m² had an all-cause mortality rate of 66% [HR: 1.66, 95% CI (1.37-2.02), p<0.01, 0% I²], which was higher than in those with an eGFR≥60 mL/min/1.73 m².

CONCLUSION

Baseline renal dysfunction has an adverse effect on-all cause mortality in patients who underwent CRT.

Long-Term Echocardiographic Outcome in Super-Responders to Cardiac Resynchronization Therapy and the Association With Mortality and Defibrillator Therapy

Super-response to cardiac resynchronization therapy (CRT) is associated with significant left ventricular (LV) reverse remodeling and improved clinical outcome. The study aimed to: (1) evaluate whether LV reverse remodeling remains sustained during long-term follow-up in super-responders and (2) analyze the association between the course of LV reverse remodeling and ventricular arrhythmias. Of all, primary prevention super-responders to CRT were selected. Super-response was defined as LV end-systolic volume reduction of ≥30% 6 months after device implantation. Cox regression analysis was performed to investigate the association of LV ejection fraction (LVEF) as time-dependent variable with implantable-cardioverter defibrillator (ICD) therapy and mortality. A total of 171 super-responders to CRT-defibrillator were included (mean age 67 ± 9 years; 66% men; 37% ischemic heart disease). Here of 129 patients received at least 1 echocardiographic evaluation after a median follow-up of 62 months (25th to 75th percentile, 38 to 87). LV end-diastolic volume, LV end-systolic volume, and LVEF after 6-month follow-up were comparable with those after 62-month follow-up (p = 0.90, p = 0.37, and p = 0.55, respectively). Changes in LVEF during follow-up in super-responders were independently associated with appropriate ICD therapy (hazard ratio 0.94, 95% CI 0.90 to 0.98; p = 0.005) and all-cause mortality (hazard ratio 0.95, 95% CI 0.91 to 1.00; p = 0.04). A 5% increase in LVEF was associated with a 1.37 times lower risk of appropriate ICD therapy and a 1.30 times lower risk of mortality. In conclusion, LV reverse remodeling in super-responders to CRT remains sustained during long-term follow-up. Changes in LVEF during follow-up were associated with mortality and ICD therapy.

Diabetes Mellitus and Outcomes of Cardiac Resynchronization With Implantable Cardioverter-Defibrillator Therapy in Older Patients With Heart Failure

Background—

Large-scale data on outcomes with cardiac resynchronization therapy with defibrillator in patients with diabetes mellitus are limited. We compared outcomes after cardiac resynchronization therapy with defibrillator implantation among patients with heart failure who have diabetes mellitus versus those without diabetes mellitus.

Methods and Results—

Survival curves and covariate adjusted hazard ratio (HR) or odds ratio were used to assess the risks for death, readmission, and device-related complications by diabetes mellitus status among 18 428 patients at least 65 years old receiving cardiac resynchronization therapy with defibrillator from the National Cardiovascular Data Registry, implantable cardioverter-defibrillator registry between 2006 and 2009, with up to 3 years of follow-up. Accounting for differences between groups, compared with those without diabetes mellitus (n=11 345), patients with diabetes mellitus (n=7083) had a higher risk of death both at 1 year (HR, 1.16 [95% confidence interval (CI), 1.05–1.29]; P =0.0037) and 3 years (HR, 1.21 [1.14–1.29]; P <0.001) after device implantation and higher risks of all-cause readmission (sub-HR, 1.16 [1.11–1.21] at 1 year; P <0.0001; sub-HR, 1.15 [1.11–1.19] at 3 years; P <0.0001) and heart failure–related readmission (sub-HR, 1.18 [1.09–1.28] at 1 year; P <0.0001; and sub-HR, 1.22 [1.15–1.30] at 3 years; P <0.0001). Device-related complications within 90 days did not differ between those with and without diabetes mellitus (odds ratio: 0.90 [0.77–1.06]; P =0.37). Interactions of age, sex, ischemic cardiomyopathy, renal failure, or QRS duration were not significant.

Conclusions—

In older patients with heart failure receiving cardiac resynchronization therapy with defibrillator, diabetes mellitus was independently associated with greater risks of death and rehospitalization, but similar risks of procedural complications.

The relative role of patient physiology and device optimisation in cardiac resynchronisation therapy: A computational modelling study

Cardiac resynchronisation therapy (CRT) is an established treatment for heart failure, however the effective selection of patients and optimisation of therapy remain controversial. While extensive research is ongoing, it remains unclear whether improvements in patient selection or therapy planning offers a greater opportunity for the improvement of clinical outcomes. This computational study investigates the impact of both physiological conditions that guide patient selection and the optimisation of pacing lead placement on CRT outcomes. A multi-scale biophysical model of cardiac electromechanics was developed and personalised to patient data in three patients. These models were separated into components representing cardiac anatomy, pacing lead location, myocardial conductivity and stiffness, afterload, active contraction and conduction block for each individual, and recombined to generate a cohort of 648 virtual patients. The effect of these components on the change in total activation time of the ventricles (ΔTAT) and acute haemodynamic response (AHR) was analysed. The pacing site location was found to have the largest effect on ΔTAT and AHR. Secondary effects on ΔTAT and AHR were found for functional conduction block and cardiac anatomy. The simulation results highlight a need for a greater emphasis on therapy optimisation in order to achieve the best outcomes for patients.

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Ventricular conduction block indicates patient response to CRT.

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Placement of CRT pacing leads strongly affects response to therapy.

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Improved treatment planning should be prioritised in order to maximise CRT outcomes.

Cardiac Resynchronization Therapy in CKD Stage 4 Patients

BACKGROUND AND OBJECTIVES

Cardiac resynchronization therapy (CRT) is a well established heart failure treatment that has shown to improve renal function. However, landmark CRT trials excluded patients with severe renal dysfunction. Therefore, this study evaluated the effect of CRT on renal function and long-term prognosis in patients with stage 4 CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study evaluated 73 consecutive CRT patients (71±10 years) with stage 4 CKD who underwent echocardiographic and renal function evaluation at baseline and 6-month follow-up between 2000 and 2012. As a control group, 18 patients with stage 4 CKD who received an implantable cardioverter defibrillator (ICD) were selected. CRT recipients with ≥15% reduction in left ventricular end-systolic volume at 6-month follow-up were classified as CRT responders. During long-term follow-up (median, 33 months), appropriate defibrillator therapy, heart failure hospitalizations, and all-cause mortality (combined end point) were recorded.

RESULTS

At 6-month follow-up, a significant reduction in left ventricular end-systolic volume was observed in CRT patients compared with patients with ICD (from 159±78 to 145±78 ml in CRT patients and from 126±54 to 119±49 ml in ICD patients; P=0.05), and CRT response was observed in 22 patients (30%). Compared with ICD patients, eGFR improved among CRT patients (from 25±4 to 30±9 ml/min per 1.73 m(2); interaction time and group, P=0.04) and was more pronounced among CRT responders (25±3 to 34±9 ml/min per 1.73 m(2); P<0.001). The combined end point was observed in 17 ICD and 62 CRT patients. CRT patients showed superior survival compared with ICD patients (log-rank P=0.03). More importantly, CRT response was independently associated with improved survival free from the combined end point (hazard ratio, 0.51; 95% confidence interval, 0.27 to 0.98; P=0.04) after adjustment for clinical and echocardiographic parameters.

CONCLUSIONS

Response to CRT occurs in approximately 30% of patients with stage 4 CKD, which is less than in the average CRT population. CRT was associated with better clinical outcome, and particularly, CRT response was associated with improvement in eGFR and better long-term prognosis.

Effect of Cardiac Resynchronization Therapy in Patients With Insulin-Treated Diabetes Mellitus

Diabetes mellitus (DM) modify outcome in patients with heart failure (HF). We aimed to analyze the risk for death, HF alone, combined end point HF/death, and ventricular tachycardia/ventricular fibrillation (VT/VF) in patients with mild HF without DM and in those with DM, further stratified by the presence of insulin treatment. We determined whether cardiac resynchronization therapy with defibrillator (CRT-D) versus implantable cardioverter defibrillator improves clinical outcomes in these 3 subgroups. Cox proportional hazards regression models were used to analyze 1,278 patients with left bundle branch block in the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy trial. Treatment with CRT-D versus implantable cardioverter defibrillator was associated with 76% risk reduction in all-cause mortality (hazard ratio 0.24; 95% confidence interval 0.08 to 0.74, p = 0.012) in subgroup of diabetic patients treated with insulin only (interaction p = 0.043). Significant risk reduction in HF alone, HF/death, and the VT/VF after CRT-D was observed across investigated groups and similar left ventricular reverse remodeling to CRT-D. In conclusion, patients with mild HF with DM treated with insulin derive significant risk reduction in mortality, in HF, and VT/VF after implantation of CRT-D. Diabetic patients not receiving insulin benefit from CRT-D by reduction of HF events.

Identification of Genetic Markers for Treatment Success in Heart Failure Patients

Background—

Cardiac resynchronization therapy (CRT) can improve ventricular size, shape, and mass and reduce mitral regurgitation by reverse remodeling of the failing ventricle. About 30% of patients do not respond to this therapy for unknown reasons. In this study, we aimed at the identification and classification of CRT responder by the use of genetic variants and clinical parameters.

Methods and Results—

Of 1421 CRT patients, 207 subjects were consecutively selected, and CRT responder and nonresponder were matched for their baseline parameters before CRT. Treatment success of CRT was defined as a decrease in left ventricular end-systolic volume >15% at follow-up echocardiography compared with left ventricular end-systolic volume at baseline. All other changes classified the patient as CRT nonresponder. A genetic association study was performed, which identified 4 genetic variants to be associated with the CRT responder phenotype at the allelic ( P <0.035) and genotypic ( P <0.031) level: rs3766031 ( ATPIB1 ), rs5443 ( GNB3 ), rs5522 ( NR3C2 ), and rs7325635 ( TNFSF11 ). Machine learning algorithms were used for the classification of CRT patients into responder and nonresponder status, including combinations of the identified genetic variants and clinical parameters.

Conclusions—

We demonstrated that rule induction algorithms can successfully be applied for the classification of heart failure patients in CRT responder and nonresponder status using clinical and genetic parameters. Our analysis included information on alleles and genotypes of 4 genetic loci, rs3766031 ( ATPIB1 ), rs5443 ( GNB3 ), rs5522 ( NR3C2 ), and rs7325635 ( TNFSF11 ), pathophysiologically associated with remodeling of the failing ventricle.

Impact of diabetes mellitus on the clinical response to cardiac resynchronization therapy in elderly people

Heart failure (HF) and type 2 diabetes mellitus (T2DM) exhibit a well-established interrelationship and a growing prevalence, in particular in elderly people. Cardiac resynchronization therapy (CRT) has been shown to improve myocardial function in patients with HF and cardiac dyssynchrony. However, reports on CRT in diabetic elderly patients are limited and controversial. Therefore, the aim of the present study was to investigate the functional role of T2DM on the effectiveness of CRT at advanced age. In this single-center prospective study, we enrolled 72 HF patients over 75 years old with and without T2DM who underwent CRT implant. Detailed clinical and instrumental data, including cardiac ultrasound analysis, 6-min walk test, and quality-of-life evaluation, were collected at baseline and at 1-year follow-up. At the time of implantation, 44.4 % of patients had T2DM, of which 62.5 % were well controlled with diet and hypoglycemic drugs and 37.5 % were treated by insulin therapy. After 1 year, CRT improved myocardial ventricular geometry and functional capacity in a comparable proportion of diabetic and non-diabetic patients alongside with a similar amelioration in the functional status. Taken together, our findings demonstrate that diabetic patients >75 years old exhibit a response to CRT that is comparable to non-diabetic subjects.

Evaluation of subclinical left ventricular dysfunction in diabetic patients: longitudinal strain velocities and left ventricular dyssynchrony by two-dimensional speckle tracking echocardiography study

BACKGROUND

We evaluated left ventricular (LV) subclinical systolic dysfunction in diabetes mellitus patients using two-dimensional speckle tracking echocardiography (STE) for early detection of changes in LV longitudinal strain (ST) or synchronized contraction.

METHODS

To determine ST and LV dyssynchrony, 37 normal coronary and normotensive diabetes mellitus patients with LV ejection fraction >50% were enrolled and compared to 39 nondiabetic normal coronary and LV function subjects. The cases underwent standard conventional transthoracic echocardiography and tissue Doppler imaging (TDI) and STE. End-systolic ST and time-to-peak systolic strain (Ts) were measured in 18 LV segments.

RESULTS

Conventional parameters were similar between diabetic and nondiabetic subjects. In diabetic patients, significant reduction in global and segmental ST adjusted for age and body mass index, independently correlated with early diastolic velocity at the septal mitral valve annulus by TDI (P = 0.001), ratio of transmitral early and late diastolic velocities (P < 0.001), relative wall thickness (P = 0.014), glycosylated hemoglobin (P < 0.001), and fasting blood sugar (P < 0.001). These correlations were not found in the nondiabetic patients. After adjustment, presence of diabetes mellitus remained an independent correlate of reduced LV global longitudinal ST (R = 0.688, P = 0.003). Delay of Ts between the anteroseptal and posterior walls and all the LV segments was markedly higher in the diabetic group regardless of diastolic dysfunction.

CONCLUSION

In diabetic patients with normal coronary and ejection fraction, segmental and global end-systolic longitudinal ST decreased and differences between Ts among LV segments increased irrespective of diastolic dysfunction at early stage. These results suggest that there might be early detectable changes in systolic function in the natural course of diabetes mellitus by STE study.