Sex-based differences in cardiac resynchronization therapy and implantable cardioverter defibrillator therapies: effectiveness and use

Multi-Center, Community-Based Cardiac Implantable Electronic Devices Registry: Population, Device Utilization, and Outcomes

Background

The purpose of this study is to describe key elements, clinical outcomes, and potential uses of the Kaiser Permanente–Cardiac Device Registry.

Methods and Results

This is a cohort study of implantable cardioverter defibrillators (ICD), pacemakers (PM), and cardiac resynchronization therapy (CRT) devices implanted between January 1, 2007 and December 31, 2013 by ≈400 physicians in 6 US geographical regions. Registry data variables, including patient characteristics, comorbidities, indication for procedures, complications, and revisions, were captured using the healthcare system's electronic medical record. Outcomes were identified using electronic screening algorithms and adjudicated via chart review. There were 11 924 ICDs, 33 519 PMs, 4472 CRTs, and 66 067 leads registered. A higher proportion of devices were implanted in males: 75.1% (ICD), 55.0% (PM), and 66.7% (CRT), with mean patient age 63.2 years (ICD), 75.2 (PM), and 67.2 (CRT). The 30‐day postoperative incidence of tamponade, hematoma, and pneumothorax were ≤0.3% (ICD), ≤0.6% (PM), and ≤0.4% (CRT). Device failures requiring revision occurred at a rate of 2.17% for ICDs, 0.85% for PMs, and 4.93% for CRTs, per 100 patient observation years. Superficial infection rates were <0.03% for all devices; deep infection rates were 0.6% (ICD), 0.5% (PM), and 1.0% (CRT). Results were used to monitor vendor‐specific variations and were systematically shared with individual regions to address potential variations in outcomes, utilization, and to assist with the management of device recalls.

Conclusions

The Kaiser Permanente–Cardiac Device Registry is a robust tool to monitor postprocedural patient outcomes and postmarket surveillance of implants and potentially change practice patterns.

ICD and CRT use in ischemic heart disease in women

Although the role of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT) in improving outcomes in ischemic cardiomyopathy (ICM) has been described, the data regarding gender-based survival outcomes are limited. There is a higher preponderance of non-ischemic cardiomyopathy (NICM) in women, and most of the ICM literature is derived from sub-study analysis. This review summarizes the current body of literature on prognosis, pathophysiology, and the present clinical practice for device implantation in women with ICM.

Long-Term Results of Cardiac Resynchronization Therapy: A Comparison between CRT-Pacemakers versus Primary Prophylactic CRT-Defibrillators

BACKGROUND

Cardiac resynchronization therapy (CRT) with or without a defibrillator has a positive effect on mortality and morbidity for patients with heart failure. However, comparisons between CRT-defibrillators (CRT-D) and CRT-pacemakers (CRT-P) are relatively scarce outside the clinical trial setting. This study aimed to assess baseline characteristics in relation to long-term prognosis in patients treated with CRT, and to investigate the potential benefit of CRT-D versus CRT-P.

METHODS

Data were retrospectively collected from the medical records of all consecutive patients treated with CRT-P or primary prophylactic CRT-D at a large tertiary care center between 1999 and 2012. Predictors of mortality were investigated, and time-dependent analysis was performed with all-cause mortality as the primary end point.

RESULTS

A total of 705 patients were included (69.6 ± 10 years, 78% New York Heart Association classes III-IV, left ventricular ejection fraction median 25%, 16% female, 36% CRT-D). The patients were followed for a median of 59 months. Annual mortality differed between CRT-D primary prophylactic and CRT-P groups (5.3% and 11.8%, respectively), but when adjusted for covariates, CRT-D treatment (compared to CRT-P) was not associated with better long-term survival. Independent predictors of survival were: age, use of loop diuretics, hemoglobin levels, and use of renin angiotensin aldosterone system blockers.

CONCLUSIONS

In CRT treatment outside of the clinical trial setting, CRT-D treatment was not an independent predictor of long-term survival. Future research should focus on correct selection of the patients who receive enough benefit of an added defibrillator to justify CRT-D implantation instead of CRT-P treatment only.

Patient-assessed short-term positive response to cardiac resynchronization therapy is an independent predictor of long-term mortality

AIMS

Cardiac resynchronization therapy (CRT) has a well-documented positive effect on mortality and heart failure morbidity. The aim of this study was to assess the long-term survival and the predictive value of self-assessed functional status on the long-term prognosis of patients treated with CRT-pacemaker (CRT-P).

METHODS AND RESULTS

Data were retrospectively collected from medical records of 446 consecutive patients implanted with CRT-P at a large-volume Swedish tertiary care centre. Primary outcome was all-cause mortality, predictive variables were assessed by log-rank test and univariate cox regression. Three hundred and nine patients had reliable information available on early improvement after implantation and were included in the multivariate analyses. The cohort was followed for a median of 79 months and was similar in baseline characteristics compared with major controlled trials. During follow-up 204 patients died, yearly mortality was 11.7%. Early improvement of self-assessed functional status was a strong independent predictor of survival [hazard ratio, HR 0.59, confidence interval (CI) 0.40-0.87, P = 0.007], together with well-known predictors; NYHA III-IV vs I-II (HR 1.66, CI 1.09-2.536, P = 0.018), age (HR 1.05, CI 1.03-1.08, P < 0.001), male gender (HR 2.0, CI 1.11-3.45, P = 0.021), and loop diuretic use (HR 4.41, CI 1.08-18.02). Patients with early improvement of self-assessed functional status had better 2-year and 5-year survival (P < 0.001).

CONCLUSIONS

Real-life patient characteristics and predictors of outcome compare well with those in published prospective trials. Self-assessed functional status is a strong predictor of long-term survival, which may have implications for a more active follow-up of patients without spontaneous improvement.

Cardiac resynchronization therapy: a breakthrough in heart failure management

Heart failure is now considered an epidemic. In patients with heart failure, electrical and mechanical dyssynchrony, evident primarily as prolongation of the QRS-complex on the surface electrocardiogram, is associated with detrimental effects on the cardiovascular system at several levels. In the past 10 years, studies have demonstrated that by stimulating both cardiac ventricles simultaneously, or almost simultaneously [cardiac resynchronization therapy (CRT)], the adverse effects of dyssynchrony can be overcome. Here, we provide a comprehensive overview of different aspects of CRT including the rationale behind and evidence for efficacy of the therapy. Issues with regard to gender effects and patient follow-up as well as a number of unresolved concerns will also be discussed.

Predictors of sustained ventricular arrhythmia episodes in patients with primary ICD indication: male gender and AF in primary ICD prophylaxis

AIMS

Implantable cardioverter-defibrillators (ICD) reduce mortality in patients with severely impaired left ventricular function. In randomized studies, female patients are underrepresented and data on ICD therapy is limited. Atrial fibrillation (AF) is a determinant of poor prognosis but has not been consistently evaluated. We evaluated the risk factors for the occurrence of ventricular arrhythmia episodes in patients with primary ICD prophylaxis.

METHODS

Consecutive patients after ICD implantation for primary prophylaxis were followed. During follow-up, detected sustained episodes of ventricular arrhythmia were documented. Multivariate analysis controlled for propensity score was used to evaluate the correlation between gender, history of AF, and the occurrence of ventricular arrhythmia episodes.

RESULTS

A total of 400 patients (19.8% female; n = 79) were included. During follow-up, 64 patients (16%) had appropriate ICD therapy episodes. Men (18%) had significantly more often episodes than women (8%; p = 0.025). Patients with a history of AF (102, 25.5%) had significantly more often episodes (30%) compared to patients without a history of AF (11%; p < 0.001). In a multivariate model, only gender (p = 0.02) and history of AF (p < 0.001) were significantly associated predictors of the occurrence of appropriate ICD therapies during follow-up. Based on the propensity score model, the adjusted hazard ratio for male gender was 2.7 (p = 0.02) and 2.6 (p = 0.0004) for history of AF.

CONCLUSION

Male gender and history of AF are independent predictors for the occurrence of sustained ventricular arrhythmia in primary ICD prophylaxis. Further studies need to evaluate whether history of AF in female patients might be an indicator for higher risk of sudden cardiac arrhythmic death.

Heart failure patients selection for cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an established treatment for refractory chronic heart failure (CHF) patients with ventricular dyssynchrony. The patient selection for this therapy remains the basis for response improvement. Various parameters, methods and technology for identification of appropriate patient are under research. The influences of age and gender, disease progress stage such as mild and late stage CHF including right ventricular dysfunction, dyssynchrony and scar identified by imaging techniques like echocardiography, magnetic resonance and nuclear imaging, and atrial fibrillation on CRT benefits were respectively discussed. This review summarizes the current advancement in these areas.

Predictors of implantable cardioverter-defibrillator use in patients with ischemic cardiomyopathy

OBJECTIVES

The objective of this study was to identify and examine ICD utilization in a large group of eligible coronary artery bypass grafting (CABG) patients with impaired left ventricular function.

METHODS

We conducted a retrospective study of ICD eligible patients who had previously undergone CABG surgery between March 1, 1995 and June 30, 2008 at a single tertiary care institution. All patients with a pre-operative left ventricular ejection fraction (LVEF) ≤ 35% were considered ICD eligible. The events of interest were ICD implantation and mortality, based on administrative data linkage.

RESULTS

A total of 1,169 out of 11,931 CABG patients operated on during the same period had LVEF ≤ 35% and were defined as ICD eligible (mean EF = 27.3% +/- 6.4%). Of these eligible patients, only 101 received an ICD during follow-up (8.6%). The median time to implant was 255 days (14-1078). The single variable that independently predicted eventual ICD implantation was a history of arrhythmia (OR = 7.4; CI, 4.4-12.2). The variables that predicted not having an ICD implanted during follow-up included the need for urgent CABG (OR = 0.5; CI, 0.2-0.9), age > 70 years (OR = 0.5; CI, 0.3-0.8), female gender (OR = 0.2; CI,0.1-0.6), or having chronic obstructive lung disease (OR = 0.5; CI,0.3-0.8). As a data validation step, a series of consecutive patient records were reviewed (n=80) showing that fewer than 23% underwent appropriate follow-up EF assessment post revascularization.

CONCLUSION

Our findings suggest that CABG patients with ischemic cardiomyopathy have low rates of ICD utilization. This is particularly evident among females and elderly patients. Furthermore our data suggests that few patients post-revascularization undergo follow-up EF assessment despite current guidelines likely contributing to the low rates of ICD utilization.

Recent advances in the management of chronic stable angina I: approach to the patient, diagnosis, pathophysiology, risk stratification, and gender disparities

The potential importance of both prevention and personal responsibility in controlling heart disease, the leading cause of death in the USA and elsewhere, has attracted renewed attention. Coronary artery disease is preventable, using relatively simple and inexpensive lifestyle changes. The inexorable rise in the prevalence of obesity, diabetes, dyslipidemia, and hypertension, often in the risk cluster known as the metabolic syndrome, drives the ever-increasing incidence of heart disease. Population-wide improvements in personal health habits appear to be a fundamental, evidence based public health measure, yet numerous barriers prevent implementation. A common symptom in patients with coronary artery disease, classical angina refers to the typical chest pressure or discomfort that results when myocardial oxygen demand rises and coronary blood flow is reduced by fixed, atherosclerotic, obstructive lesions. Different forms of angina and diagnosis, with a short description of the significance of pain and silent ischemia, are discussed in this review. The well accepted concept of myocardial oxygen imbalance in the genesis of angina is presented with new data about clinical pathology of stable angina and acute coronary syndromes. The roles of stress electrocardiography and stress myocardial perfusion scintigraphic imaging are reviewed, along with the information these tests provide about risk and prognosis. Finally, the current status of gender disparities in heart disease is summarized. Enhanced risk stratification and identification of patients in whom procedures will meaningfully change management is an ongoing quest. Current guidelines emphasize efficient triage of patients with suspected coronary artery disease. Many experts believe the predictive value of current decision protocols for coronary artery disease still needs improvement in order to optimize outcomes, yet avoid unnecessary coronary angiograms and radiation exposure. Coronary angiography remains the gold standard in the diagnosis of coronary artery obstructive disease. Part II of this two part series will address anti-ischemic therapies, new agents, cardiovascular risk reduction, options to treat refractory angina, and revascularization.

Sex and gender differences in myocardial hypertrophy and heart failure

Heart failure (HF) is a leading cause of cardiovascular mortality and morbidity in the Western world. It affects men at younger age than women. Women have more frequently diastolic HF, associated with the major risk factors of diabetes and hypertension and men have more frequently systolic HF because of coronary artery disease. Under stress, male hearts develop more easily pathological hypertrophy with dilatation and poor systolic function than female hearts. Women with aortic stenosis have more concentric hypertrophy with better systolic function, less upregulation of extracellular matrix genes and better reversibility after unloading. Stressed female hearts maintain energy metabolism better than male hearts and are better protected against calcium overload. Estrogens and androgens and their receptors are present in the myocardium and lead to coordinated regulation of functionally relevant pathways. Atrial fibrillation (AF) is a more ominous sign in women than in men. Men with end-stage cardiomyopathy more frequently have auto-antibodies than women. Women receive less guideline-based diagnostics and therapy. Expensive and invasive therapies such as advanced pacemakers and transplantation are underused in women. Drug studies point at sex differences in efficacy. Despite worse diagnostics and therapy, prognosis is better in women than in men.

Use of implantable cardioverter defibrillators for primary prevention in the community: do women and men equally meet trial enrollment criteria?

BACKGROUND

Fewer women than men undergo implantable cardioverter defibrillator (ICD) implantation for the primary prevention of sudden cardiac death. The criteria used to select patients for ICD implantation may be more permissive among men than for women. We hypothesized that women who undergo primary prevention ICD implantation more often meet strict trial enrollment criteria for this therapy.

METHODS

We studied 59,812 patients in the National Cardiovascular Data Registry ICD registry undergoing initial primary prevention ICD placement between January 2005 and April 2007. Patients were classified as meeting or not meeting enrollment criteria of either the MADIT-II or SCD-HeFT trials. Multivariable analyses assessed the association between gender and concordance with trial criteria adjusting for demographic, clinical, and system characteristics.

RESULTS

Among the cohort, 27% (n = 16,072) were women. Overall, 85.2% of women and 84.5% of men met enrollment criteria of either trial (P = .05). In multivariable analyses, women were equally likely to meet trial criteria (OR 1.04, 95% CI 0.99-1.10) than men. Significantly more women than men met the trial enrollment criteria among patients older than age 65 (86.6% of women vs 85.3% of men, OR 1.11, 95% CI 1.03-1.19), but this difference was not found among younger patients (82.5% of women vs 83.0% of men, OR 0.97, 95% CI 0.89-1.07).

CONCLUSIONS

In a national cohort undergoing primary prevention ICD implantation, older women were only slightly more likely then men to meet the enrollment criteria for MADIT II or SCD-HeFT. Relative overutilization in men is not an important explanation for gender differences in ICD implantation.

Gender differences in anxiety and concerns about the cardioverter defibrillator

BACKGROUND

Little is known about gender differences in the response to implantable cardioverter defibrillator (ICD) therapy. We compared female and male ICD patients on anxiety, depression, health-related quality of life (HRQL), ICD concerns, and ICD acceptance.

METHODS

A cohort of consecutive, surviving patients (n = 535; mean age = 61.5 +/- 14.4, 81.9% male) implanted with an ICD between 1989 and 2006 completed the Hospital Anxiety and Depression Scale, the Short-Form Health Survey (SF-36), the ICD concerns questionnaire, and the Florida Patient Acceptance Survey.

RESULTS

High levels of anxiety (52% vs 34%, P < 0.001) and ICD concerns (34% vs 16%, P = 0.001) were more prevalent in women than men, whereas no significant differences were found on depression and device acceptance (Ps > 0.05). Women were more anxious (odds ratio [OR]: 2.60 [95% confidence interval (CI): 1.46-4.64], P < 0.01) and had more ICD concerns (OR: 1.81 [95% CI: 1.09-3.00], P < 0.05) than men, adjusting for demographic and clinical characteristics. Those ICD patients experiencing shocks were also more anxious (OR: 2.02 [95% CI: 1.20-3.42], P < 0.01) and had higher levels of ICD concerns (OR: 2.70 [95% CI: 1.76-4.16], P < 0.01). In multivariable analysis of variance, significant gender differences were found for only three of the eight subscales of the SF-36 (the physical social functioning and the mental health subscale), with women reporting poorer HRQL on all three subscales.

CONCLUSIONS

Women were more prone to experience anxiety and ICD concerns compared to men regardless of whether they had experienced shocks. In clinical practice, female ICD patients should be closely monitored, and if warranted offered psychosocial intervention, as increased anxiety has been shown to precipitate arrhythmic events in defibrillator patients.

A prognostic index relating 24-hour ambulatory blood pressure to cardiac events in ischemic cardiomyopathy following defibrillator implantation

BACKGROUND

We assessed the role of left ventricular ejection fraction and of ambulatory blood pressure monitoring (ABPM) to predict cardiac death and heart failure in patients with defibrillator fulfilling MADIT II criteria. ABPM variables assessed included: mean 24 hours diastolic and systolic blood pressure, mean 24 hours heart rate, and pulse pressure.

METHODS

We studied 105 consecutive patients (age 67 +/- 11), all with a defibrillator and ejection fraction <or= 30%).

RESULTS

At 1-year follow-up, there were 29 events (25%), three cardiac deaths, and 26 hospitalizations for heart failure. Age, creatinine, mean 24 hours diastolic blood pressure, and mean 24 hours systolic blood pressure (but not ejection fraction) were associated with events. A prognostic index (PI) was built by age and ABPM variables, according to the formula (120--age) + (mean 24 hours diastolic blood pressure + mean 24 hours systolic blood pressure). Receiver operating characteristic curves showed the best cutoff for PI = 220 (sensitivity 81%, specificity 71%, positive predictive value 56%, negative predictive value 88%). Cox regression analysis confirmed the significant association between lower PI (< 220) and clinical events (HR 4.8, 95% CI 1.8-12.3, P = 0.0001 for PI). Overall, 12% of patients with high PI values (>or= 220 n = 71) had clinical events at 12-month follow-up, compared with 61% of patients with low PI (< 220 n = 34) (P < 0.0001).

CONCLUSION

The PI built by mean 24 hours diastolic and systolic blood pressure and age could be a simple method to stratify risk of cardiac death and acute heart failure in MADIT II patients, in whom ejection fraction, uniformly depressed, is not predictive.

Gender- and age-related outcomes of cardiac resynchronization therapy: a pilot observational study

BACKGROUND

Cardiac resynchronization therapy (CRT) has been reported to improve clinical status and survival, and shorten hospitalization rates, in patients with heart failure (HF). However, questions remain regarding the success of CRT in different subgroups of patients with HE.

OBJECTIVE

We assessed whether CRT response was related to gender or age in patients with HE.

METHODS

In a longitudinal observational study, patients with severe HF (New York Heart Association [NYHA] class III or IV, left ventricular ejection fraction [LVEF] <or=35%, and QRS duration >120 ms with left bundle branch block configuration) were enrolled. Clinical electrophysiologic and echocardiographic evaluations were performed before, and 3 and 6 months after, CRT implantation.

RESULTS

A total of 65 Iranian patients (50 men, 15 women; mean [SD] age, 60.3 [10.3] years; baseline NYHA class, 3.1 [0.36]; QRS duration, 144 [14] ms; LVEF, 21% [7.3%]; left ventricular end-diastolic diameter (LVEDD), 6.8 [0.56] mm) were evaluated. NYHA class, QRS duration, LVEF, and LVEDD were significantly improved at 3- and 6-month follow-ups both in patients aged <or=60 years and in those aged >60 years (P < 0.001, except for aged <or=60 years after 3-month follow-up [P = 0.002]). All these parameters were significantly improved in men at 3- and 6-month follow-ups (P < 0.001). NYHA class (P = 0.002), QRS duration (P = 0.001), LVEF (P = 0.013 at 3 months and <0.001 at 6 months), and LVEDD (P = 0.007 at 3 months and <0.001 at 6 months) also were significantly improved in women. At 3- and 6-month follow-ups, there were no significant differences in improvement of these factors between the 2 age groups of patients.

CONCLUSION

CRT response in these patients with HF did not appear to be gender or age related at 3- and 6-month follow-ups in this small observational study. Confirmation of these findings by larger studies is needed.

Improving the quality of care for women with cardiovascular disease: report of a DCRI Think Tank, March 8 to 9, 2007

BACKGROUND

Differences in pathophysiology, diagnosis, and treatment of women with cardiovascular disease compared with men has become a major focus during the past decade. Nevertheless, little attention has focused on improving the quality of healthcare in women compared with other areas of cardiovascular medicine.

METHODS

To address this deficit, Duke University Medical Center convened a national Duke Clinical Research Institute (DCRI) Think Tank meeting, including basic science and clinical researchers, payers, legislators, clinical experts, government regulators, and members of the pharmaceutical and device industries. This report provides an overview of the discussions and proposed solutions.

RESULTS

Discussion concentrated on the development of strategies to improve the quality of health care for women with heart disease. Key components to improve quality care include: (1) enhance the quantity and quality of evidence-based medicine to guide care in women through improvements in trial design, enrollment and retention of women subjects, results analysis and reporting, and better incentives to perform research in women; (2) provide incentives to develop better data in women through mandating changes in the drug and device development and approval processes; (3) incorporate specific recommendations for women into guidelines when data are sufficient; and (4) apply proven sex-based differences in risk stratification, diagnostic testing, and drug usage and dosing in clinical care. Examples of possible strategies are included.

CONCLUSION

The above approach represents a necessary, but not sufficient, platform to improve the overall quality of healthcare in women with cardiovascular disease.

More reasons why men and women are not the same (gender differences in electrophysiology and arrhythmias)

It has become increasingly apparent in recent years that there are important differences in the presentation and clinical course of many cardiovascular disorders in men and women. These gender differences extend to clinical cardiac electrophysiology, with respect to basic electrophysiology as well as the presentation and clinical courses of many arrhythmias. Women have been noted to have higher heart rates at rest and longer corrected QT intervals compared with men. Differences in gender hormones may explain some of these findings, but precisely how is still not well understood. Differences have also been documented in the incidence and prevalence of specific arrhythmias, including atrial fibrillation, other supraventricular tachycardias, and sudden cardiac death. Variations in arrhythmia frequency with respect to the menstrual cycle have been observed. In addition, an increase in arrhythmia frequency or the new onset of arrhythmias has been noted during pregnancy. With the increasing use of implantable cardioverter defibrillators and cardiac resynchronization therapy, it has been shown that men and women derive equal survival and symptom reduction benefit. However, it has been found that the use of these devices in women is much lower than would be expected from the prevalence of disease in the population. The reasons for this lower utilization rate are not well understood and remain to be explored. In conclusion, the goal of this review is to summarize the currently available published reports regarding gender differences in cardiac electrophysiology and arrhythmias and to provide an update from recent studies.