Epidemiology of pacemaker procedures among Medicare enrollees in 1990, 1995, and 2000

Assessing risk of recurrent small bowel obstruction after non-operative management in patients with history of intra-abdominal surgery: a population-based comprehensive analysis in Taiwan

BACKGROUND

Despite a significant 30% ten-year readmission rate for SBO patients, investigations into recurrent risk factors after non-operative management are scarce. The study aims to generate a risk factor scoring system, the 'Small Bowel Obstruction Recurrence Score' (SBORS), predicting 6-month recurrence of small bowel obstruction (SBO) after successful non-surgical management in patients who have history of intra-abdominal surgery.

METHODS

We analyzed data from patients aged ≥ 18 with a history of intra-abdominal surgery and diagnosed with SBO (ICD-9 code: 560, 568) and were successful treated non-surgically between 2004 and 2008. Participants were divided into model-derivation (80%) and validation (20%) group.

RESULTS

We analyzed 23,901 patients and developed the SBORS based on factors including the length of hospital stay > 4 days, previous operations > once, hemiplegia, extra-abdominal and intra-abdominal malignancy, esophagogastric surgery and intestino-colonic surgery. Scores > 2 indicated higher rates and risks of recurrence within 6 months (12.96% vs. 7.27%, OR 1.898, p < 0.001 in model-derivation group, 12.60% vs. 7.05%, OR 1.901, p < 0.001 in validation group) with a significantly increased risk of mortality and operative events for recurrent episodes. The SBORS model demonstrated good calibration and acceptable discrimination, with an area under curve values of 0.607 and 0.599 for the score generation and validation group, respectively.

CONCLUSIONS

We established the effective 'SBORS' to predict 6-month SBO recurrence risk in patients who have history of intra-abdominal surgery and have been successfully managed non-surgically for the initial obstruction event. Those with scores > 2 face higher recurrence rates and operative risks after successful non-surgical management.

Mortality Prediction Model before Surgery for Acute Mesenteric Infarction: A Population-Based Study

Surgery for acute mesenteric infarction (AMI) is associated with high mortality. This study aimed to generate a mortality prediction model to predict the 30-day mortality of surgery for AMI. We included patients ≥18 years who received bowel resection in treating AMI and randomly divided into the derivation and validation groups. After multivariable analysis, the ‘Surgery for acute mesenteric infarction mortality score’ (SAMIMS) system was generated and was including age >62-year-old (3 points), hemodialysis (2 points), congestive heart failure (1 point), peptic ulcer disease (1 point), diabetes (1 point), cerebrovascular disease (1 point), and severe liver disease (4 points). The 30-day-mortality rates in the derivation group were 4.4%, 13.4%, 24.5%, and 32.5% among very low (0 point), low (1−3 point(s)), intermediate (4−6 points), and high (7−13 points)-risk patients. Compared to the very-low-risk group, the low-risk (OR = 3.332), intermediate-risk (OR = 7.004), and high-risk groups (OR = 10.410, p < 0.001) exhibited higher odds of 30-day mortality. We identified similar results in the validation group. The areas under the ROC curve were 0.677 and 0.696 in the derivation and validation groups. Our prediction model, SAMIMS, allowed for the stratification of the patients’ 30-day-mortality risk of surgery for acute mesenteric infarction.

Lifetime Risks of Valvular Heart Disease and Pacemaker Use in Patients With Ankylosing Spondylitis

Background The likelihoods of valvular heart disease ( VHD ) and conduction abnormalities in patients with ankylosing spondylitis ( AS p) are poorly defined. Knowing their lifetime risks of VHD and pacemaker use would help inform whether cardiac screening should be done. Methods and Results Patients with AS p and a comparison group without AS p were identified among US Medicare beneficiaries in 1999 to 2013. Frequencies of VHD and pacemaker use were compared in 4 age groups: 65 to 69 years, 70 to 74 years, 75 to 79 years, and 80 years or older, as were rates of valve surgeries, a measure of VHD severity, and new pacemaker insertions. Outcomes were compared between 42 327 patients with AS p and 19 211 703 patients without AS p. The prevalence of aortic valve disease in patients with AS p increased with age (2.6%, 6.7%, 10.9%, and 17.1%), as did the prevalence of mitral valve disease. Risks of VHD were slightly but significantly higher in patients with AS p (adjusted odds ratios 1.06-1.51). Rates of aortic valve replacement/repair were also higher in patients with AS p than in the comparison group (125 versus 93; 183 versus 149; 261 versus 208; 279 versus 191 per 100 000 patient-years in the 4 age groups). Rates of mitral valve surgery did not differ between groups. Among patients with AS p, pacemaker use ranged from 1.0% to 7.6% across age groups, and was slightly higher than in controls (odds ratio range 1.11-1.32). Conclusions Lifetime risks of VHD and pacemaker use in AS p increase markedly with age, but are only slightly higher than in elderly people without AS p.

The Utility of Magnetic Resonance Imaging-compatible Pacemakers in Neurosurgical Patients

Artificial implantable pacemakers have long been a challenge to neurosurgeons seeking to perform advanced diagnostic imaging on their patients. Unfortunately, while the use of implantable pacemakers has been a life-saving advance for those with cardiac arrhythmias, they also often prevent these patients from undergoing magnetic resonance imaging (MRI). There have been multiple reported cases of pacemaker failure in the context of MRI use. Recent technological advances, however, have allowed the development of pacemakers that are not affected by the MRI scanner. Similar technology has also been applied to the development of MRI-compatible spinal cord stimulators and other neurostimulation devices. In this paper, we discuss four specific neurosurgical cases where the use of MRI was critical for diagnostic and therapeutic decision-making. Current non-MRI-compatible pacemakers were exchanged for MRI-compatible pacemaker technology with some associated cost and risk. The diagnostic cranial and spinal MRIs subsequently obtained were critical for forging the ensuing neurosurgical care. Based on these cases, we extrapolate the importance of MRI-compatible pacemakers to society at large and advocate for the use of such devices in all patients going forward.

Monitoring of arrhythmia and sudden death in a hemodialysis population: The CRASH-ILR Study

INTRODUCTION

It has been suggested that sudden cardiac death (SCD) contributes around 50% of cardiovascular and 27% of all-cause mortality in hemodialysis patients. The true burden of arrhythmias and arrhythmic deaths in this population, however, remains poorly characterised. Cardio Renal Arrhythmia Study in Hemodialysis (CRASH-ILR) is a prospective, implantable loop recorder single centre study of 30 established hemodialysis patients and one of the first to provide long-term ambulatory ECG monitoring.

METHODS

30 patients (60% male) aged 68±12 years receiving hemodialysis for 45±40 months with varied etiology (diabetes 37%, hypertension 23%) and left ventricular ejection fraction (LVEF) 55±8% received a Reveal XT implantable loop recorder (Medtronic, USA) between August 2011 and October 2014. ECG data from loop recorders were transmitted at each hemodialysis session using a remote monitoring system. Primary outcome was SCD or implantation of a (tachy or bradyarrhythmia controlling) device and secondary outcome, the development of arrhythmia necessitating medical intervention.

RESULTS

During 379,512 hours of continuous ECG monitoring (mean 12,648±9,024 hours/patient), there were 8 deaths-2 SCD and 6 due to generalised deterioration/sepsis. 5 (20%) patients had a primary outcome event (2 SCD, 3 pacemaker implantations for bradyarrhythmia). 10 (33%) patients reached an arrhythmic primary or secondary end point. Median event free survival for any arrhythmia was 2.6 years (95% confidence intervals 1.6-3.6 years).

CONCLUSIONS

The findings confirm the high mortality rate seen in hemodialysis populations and contrary to initial expectations, bradyarrhythmias emerged as a common and potentially significant arrhythmic event.

Using quality indicators to compare outcomes of permanent cardiac pacemaker implantation among publicly and privately funded patients

BACKGROUND

Funding source/insurance status has been associated with disparity in the management and outcomes of cardiovascular disease, with poorer outcomes among disadvantaged groups.

AIM

Using proposed quality indicators for permanent pacemaker (PPM) implantation and administrative data, this study aimed to determine whether quality indicator-based outcomes of PPM implantation were comparable for publicly and privately funded patients within Australia's two-tier health system.

METHODS

A population-based cohort study of adults implanted with a PPM between 1995 and 2009 in Western Australia. The association of funding outcomes derived from linked administrative data was tested in multivariate logistic regression models.

RESULTS

There were 9748 PPMs implanted, 48% being among privately funded patients. The mean age was 75 years for both public and private patients. Private patients had better health status (fewer with cardiac conditions and lower non-cardiac comorbidity scores), were less likely to be an emergency admission (33% vs 60%, P < 0.001) and more likely to have dual- or triple-chamber pacing. Mean length of stay was significantly greater for private patients (4.3 (standard deviation 6.3) vs 5.1 (6.8) days <0.001), related to longer elective admissions. Crude mortality was lower for private patients in-hospital (0.7 vs 1.3%), 30-day post-procedure (1.3 vs 2.1%) and at 1 year (7.3 vs 9.5%). Emergency admission, comorbidity and other demographic and clinical factors, not funding source, were significant predictors of these outcomes.

CONCLUSIONS

There was no difference between publicly and privately funded patients in study outcomes, after adjustment for demographic and clinical factors. The exception was longer hospital stay for elective PPM among privately funded patients.

Trends in the incidence and prevalence of cardiac pacemaker insertions in an ageing population

OBJECTIVES

To determine contemporary population estimates of the prevalence of cardiac permanent pacemaker (PPM) insertions.

METHODS

A population-based observational study using linked hospital morbidity and death registry data from Western Australia (WA) to identify all incident cases of PPM insertion for adults aged 18 years or older. Prevalence rates were calculated by age and sex for the years 1995-2009 for the WA population.

RESULTS

There were 9782 PPMs inserted during 1995-2009. Prevalence rose across the study period, exceeding 1 in 50 among people aged 75 or older from 2005. This was underpinned by incidence rates which rose with age, being highest in those 85 years or older; over 500/100 000 for men throughout, and over 200/100 000 for women. Rates for patients over 75 were more than double the rates for those aged 65-74 years. Women were around 40% of cases overall. The use of dual-chamber and triple-chamber pacing increased across the study period. A cardiac resynchronisation defibrillator was implanted for 58% of patients treated with cardiac resynchronisation therapy.

CONCLUSIONS

Rates of insertion and prevalence of PPM continue to rise with the ageing population in WA. As equilibrium has probably not been reached, the demand for pacing services in similarly well-developed economies is likely to continue to grow.

What is the effect of area size when using local area practice style as an instrument?

OBJECTIVES

Discuss the tradeoffs inherent in choosing a local area size when using a measure of local area practice style as an instrument in instrumental variable estimation when assessing treatment effectiveness.

STUDY DESIGN

Assess the effectiveness of angiotensin converting-enzyme inhibitors and angiotensin receptor blockers on survival after acute myocardial infarction for Medicare beneficiaries using practice style instruments based on different-sized local areas around patients. We contrasted treatment effect estimates using different local area sizes in terms of the strength of the relationship between local area practice styles and individual patient treatment choices; and indirect assessments of the assumption violations.

RESULTS

Using smaller local areas to measure practice styles exploits more treatment variation and results in smaller standard errors. However, if treatment effects are heterogeneous, the use of smaller local areas may increase the risk that local practice style measures are dominated by differences in average treatment effectiveness across areas and bias results toward greater effectiveness.

CONCLUSION

Local area practice style measures can be useful instruments in instrumental variable analysis, but the use of smaller local area sizes to generate greater treatment variation may result in treatment effect estimates that are biased toward higher effectiveness. Assessment of whether ecological bias can be mitigated by changing local area size requires the use of outside data sources.

Follow-up of patients with new cardiovascular implantable electronic devices: is adherence to the experts' recommendations associated with improved outcomes?

BACKGROUND

A 2008 expert consensus statement recommended an in-person follow-up visit between 2 and 12 weeks after the placement of a new cardiovascular implantable electronic device (CIED).

OBJECTIVE

To assess outcomes associated with adherence to the experts' recommendations.

METHODS

By using data from the National Cardiovascular Data Registry's (NCDR) ICD Registry linked to Medicare claims, we studied the association between follow-up within 2-12 weeks after CIED placement between January 1, 2005, and September 30, 2008, and all-cause mortality and risk of readmission within 1 year.

RESULTS

Compared with patients who did not receive the recommended follow-up (n = 43,060), those who did (n = 30,256) were more likely to be older, white, to have received a cardiac resynchronization therapy-defibrillator device, to have more advanced heart failure symptoms, and to have nonischemic dilated cardiomyopathy. In Cox proportional hazards models adjusted for patient demographic and clinical factors, mortality was lower (hazard ratio [HR] 0.93; 95% confidence interval [CI] 0.88-0.98; P = .005) but cardiovascular readmission was higher (HR 1.04; 95% CI 1.01-1.08; P = .012) among patients who received initial follow-up within 2-12 weeks after CIED placement compared with those who did not. There was no association between CIED follow-up and readmission for heart failure (HR 1.00; 95% CI 0.96-1.05; P = .878) or device-related infection (HR 1.22; 95% CI 0.98-1.51; P = .075).

CONCLUSIONS

Follow-up within 2-12 weeks after CIED placement was independently associated with improved survival but increased cardiovascular readmission. Quality improvement initiatives designed to increase adherence to experts' recommendations may be warranted.

Follow-up of patients with new cardiovascular implantable electronic devices: are experts' recommendations implemented in routine clinical practice?

BACKGROUND

A 2008 expert consensus statement outlined the minimum frequency of follow-up of patients with cardiovascular implantable electronic devices (CIEDs).

METHODS AND RESULTS

We studied 38 055 Medicare beneficiaries who received a new CIED between January 1, 2005, and June 30, 2009. The main outcome measure was variation of follow-up by patient factors and year of device implantation. We determined the number of patients who were eligible for and attended an in-person CIED follow-up visit within 2 to 12 weeks, 0 to 16 weeks, and 1 year after implantation. Among eligible patients, 42.4% had an initial in-person visit within 2 to 12 weeks. This visit was significantly more common among white patients than black patients and patients of other races (43.0% versus 36.8% versus 40.5%; P<0.001). Follow-up within 2 to 12 weeks improved from 40.3% in 2005 to 55.1% in 2009 (P<0.001 for trend). The rate of follow-up within 0 to 16 weeks was 65.1% and improved considerably from 2005 to 2009 (62.3%-79.6%; P<0.001 for trend). Within 1 year, 78.0% of the overall population had at least 1 in-person CIED follow-up visit.

CONCLUSIONS

Although most Medicare beneficiaries who received a new CIED between 2005 and 2009 did not have an initial in-person CIED follow-up visit within 2 to 12 weeks after device implantation, the rate of initial follow-up improved appreciably over time. This CIED follow-up visit was significantly more common in white patients than in patients of other races.

The pathway to physician reimbursement for cardiac implantable electronic devices (CIEDs): a history and brief synopsis

Cardiac implantable electronic devices (CIEDs), despite their proven effectiveness in large clinical trials for a wide range of patients with arrhythmia and heart failure, are frequent targets for criticism regarding cost-efficiency and alleged overuse. Newer indications, such as sinus node dysfunction for pacemakers and primary prevention for implantable cardioverter-defibrillators, increased eligible patient population significantly. This lead to heightened scrutiny from payors and legislative agencies, such as prior authorization and mandatory registry participation. Despite the significant administrative burden, the efficiency of these measures to decrease abuse is not clear. In addition, professional societies, regulatory agencies, and payors may not always agree whether use of a device is appropriate for a given patient. The review focuses on past and current issues related to utilization of CIEDs, which lead to increased regulatory oversight, and the effort of professional societies, payors, and governmental agencies to improve access to these life-saving therapeutical modalities while maintaining a just and cost-efficient healthcare system.

Care of the pacemaker/implantable cardioverter defibrillator patient in the ED

As the population ages and the prevalence of cardiovascular disease increases, patients with pacemakers and implantable cardioverter defibrillators (ICDs) more commonly present to the emergency department. These patients can have complex medical issues related to and independent of their pacemaker/ICD that require careful management by the emergency physician. This article will review the major diagnostic and therapeutic considerations in the emergency care of patients with pacemakers and ICDs.

Clinical utility and safety of a protocol for noncardiac and cardiac magnetic resonance imaging of patients with permanent pacemakers and implantable-cardioverter defibrillators at 1.5 tesla

BACKGROUND

Magnetic resonance imaging (MRI) is an important diagnostic modality currently unavailable for millions of patients because of the presence of implantable cardiac devices. We sought to evaluate the diagnostic utility and safety of noncardiac and cardiac MRI at 1.5T using a protocol that incorporates device selection and programming and limits the estimated specific absorption rate of MRI sequences.

METHODS AND RESULTS

Patients with no imaging alternative and with devices shown to be MRI safe by in vitro phantom and in vivo animal testing were enrolled. Of 55 patients who underwent 68 MRI studies, 31 had a pacemaker, and 24 had an implantable defibrillator. Pacing mode was changed to "asynchronous" for pacemaker-dependent patients and to "demand" for others. Magnet response and tachyarrhythmia functions were disabled. Blood pressure, ECG, oximetry, and symptoms were monitored. Efforts were made to limit the system-estimated whole-body average specific absorption rate to 2.0 W/kg (successful in >99% of sequences) while maintaining the diagnostic capability of MRI. No episodes of inappropriate inhibition or activation of pacing were observed. There were no significant differences between baseline and immediate or long-term (median 99 days after MRI) sensing amplitudes, lead impedances, or pacing thresholds. Diagnostic questions were answered in 100% of nonthoracic and 93% of thoracic studies. Clinical findings included diagnosis of vascular abnormalities (9 patients), diagnosis or staging of malignancy (9 patients), and assessment of cardiac viability (13 patients).

CONCLUSIONS

Given appropriate precautions, noncardiac and cardiac MRI can potentially be safely performed in patients with selected implantable pacemaker and defibrillator systems.