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Kramer, Daniel

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Kramer

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Kramer, Daniel
Author's Publications: search.filters.isAuthorOfPublication.526de73d-e0b6-4a49-af45-b71c19732ea5

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Now showing 1 - 10 of 10
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    Transvenous Implantable Cardioverter-Defibrillator Lead Reliability: Implications for Postmarket Surveillance
    (John Wiley & Sons, Ltd, 2015) Kramer, Daniel; Hatfield, Laura; McGriff, Deepa; Ellis, Christopher R; Gura, Melanie T; Samuel, Michelle; Retel, Linda Kallinen; Hauser, Robert G
    Background: As implantable cardioverter-defibrillator technology evolves, clinicians and patients need reliable performance data on current transvenous implantable cardioverter-defibrillator systems. In addition, real-world reliability data could inform postmarket surveillance strategies directed by regulators and manufacturers. Methods and Results: We evaluated Medtronic Sprint Quattro, Boston Scientific Endotak, and St Jude Medical Durata and Riata ST Optim leads implanted by participating center physicians between January 1, 2006 and September 1, 2012. Our analytic sample of 2653 patients (median age 65, male 73%) included 445 St Jude, 1819 Medtronic, and 389 Boston Scientific leads. After a median of 3.2 years, lead failure was 0.28% per year (95% CI, 0.19 to 0.43), with no statistically significant difference among manufacturers. Simulations based on these results suggest that detecting performance differences among generally safe leads would require nearly 10 000 patients or very long follow-up. Conclusions: Currently marketed implantable cardioverter-defibrillator leads rarely fail, which may be reassuring to clinicians advising patients about risks and benefits of transvenous implantable cardioverter-defibrillator systems. Regulators should consider the sample size implications when designing comparative effectiveness studies and evaluating new technology for preventing sudden cardiac death.
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    Patient Activity and Survival Following Implantable Cardioverter-Defibrillator Implantation: The ALTITUDE Activity Study
    (John Wiley & Sons, Ltd, 2015) Kramer, Daniel; Mitchell, Susan; Monteiro, Joao; Jones, Paul W; Normand, Sharon-Lise; Hayes, David L; Reynolds, Matthew R
    Background: Physical activity data are collected automatically by implantable cardioverter-defibrillators (ICDs). Though these data potentially provide a quantifiable and easily accessible measure of functional status, its relationship with survival has not been well studied. Methods and Results: Patients enrolled in the Boston Scientific LATITUDE remote monitoring system from 2008 to 2012 with ICDs were eligible. Remote monitoring data were used to calculate mean daily activity at baseline (30 to 60 days after implantation), and longitudinally. Cox regression was used to examine the association between survival and increments of 30 minutes/day in both (1) mean baseline activity and (2) time-varying activity, with both adjusted for demographic and device characteristics. A total of 98 437 patients were followed for a median of 2.2 years (mean age of 67.7±13.1 years; 71.7% male). Mean baseline daily activity was 107.5±66.2 minutes/day. The proportion of patients surviving after 4 years was significantly higher among those in the most versus least active quintile of mean baseline activity (90.5% vs. 50.0%; log-rank P value, <0.001). Lower mean baseline activity (i.e., incremental difference of 30-minutes/day) was independently associated with a higher risk of death (adjusted hazard ratio [AHR], 1.44; 95% confidence interval [CI], 1.427 to 1.462). Time-varying activity was similarly associated with a higher risk of death (AHR, 1.48; 95% CI, 1.451 to 1.508), indicating that a patient having 30 minutes per day less activity in a given month has a 48% increased hazard for death when compared to a similar patient in the same month. Conclusions: Patient activity measured by ICDs strongly correlates with survival following ICD implantation.
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    Frailty, Physical Activity, and Mobility in Patients With Cardiac Implantable Electrical Devices
    (John Wiley and Sons Inc., 2017) Kramer, Daniel; Tsai, Timothy; Natarajan, Poorna; Tewksbury, Elise; Mitchell, Susan; Travison, Thomas
    Background: This study aimed to demonstrate the feasibility of measuring frailty in patients with cardiac implantable electrical devices while validating the physiologic significance of device‐detected physical activity by evaluating its association with frailty and mobility. Methods and Results: Outpatients with cardiac implantable electrical devices compatible with physical activity analysis with at least 7 days of data were eligible. Office testing included frailty status (Study of Osteoporotic Fractures instrument), gait speed (m/s), mobility according to the Timed Up and Go (TUG) test (seconds), and daily physical activity (h/d) as measured by cardiac implantable electrical device. Among 219 patients, Study of Osteoporotic Fractures testing found 39.7% to be robust, 47.5% prefrail, and 12.8% frail. The mean gait speed for the cohort was 0.8±0.3 m/s, mean TUG time was 10.9±4.4 seconds, and mean activity was 2.8±1.9 h/d. Frail patients were markedly more likely to have gait speeds <0.8 m/s (OR 6.25, 95% CI 1.79‐33.3). In unadjusted analyses each 1‐hour increase in mean daily activity was associated with a 46% reduction of frail phenotype (OR 0.54, 95% CI 0.40‐0.74) versus robust and with a 27% reduction in the odds of having the prefrail phenotype (OR 0.73, 95% CI 0.62‐0.86). After adjustment this association per hour of activity persisted, with an adjusted OR for frailty of 0.71 (95% CI 0.51‐0.99) and adjusted OR for prefrailty of 0.81 (95% CI 0.67‐0.99). Conclusions: Frailty and mobility limitation are common among cardiac implantable electrical device patients and are correlated to device‐detected physical activity.
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    The Decisions, Interventions, and Goals in ImplaNtable Cardioverter‐DefIbrillator TherapY (DIGNITY) Pilot Study
    (John Wiley and Sons Inc., 2017) Kramer, Daniel; Habtemariam, Daniel; Adjei‐Poku, Yaw; Samuel, Michelle; Engorn, Diane; Reynolds, Matthew R.; Mitchell, Susan
    Background: Implantable cardioverter‐defibrillators (ICDs) are commonly implanted in older patients, including those with multiple comorbidities. There are few prospective studies assessing the clinical course and end‐of‐life circumstances for these patients. Methods and Results: We prospectively followed 51 patients with ICDs for up to 18 months to longitudinally assess in terms of (1) advance care planning, (2) health status, (3) healthcare utilization, and (4) end‐of‐life circumstances through quarterly phone interviews and electronic medical record review. The mean age was 71.1±8.3, 74.5% were men, and 19.6% were non‐white. Congestive heart failure was predominant (82.4%), as was chronic kidney disease (92%). At baseline, a total of 12% of subjects met criteria for major depression, and 78.4% met criteria for mild cognitive impairment. From this initial study cohort, 76% survived to 18 months and completed all follow‐up interviews, 18% died, and 19% withdrew or were lost to follow‐up. Though living will completion and healthcare proxy assignment were common (cumulative outcome at 18 months 88% and 98%, respectively), discussions of prognosis were uncommon (baseline, 9.8%; by 18 months, 22.7%), as were conversations regarding ICD deactivation (baseline, 15.7%; by 18 months, 25.5%). Five decedents with available data received shocks in the days immediately prior to death, including 3 of whom ultimately had their ICDs deactivated prior to death. Conclusions: We demonstrated the feasibility of prospective enrollment and follow‐up of older, vulnerable ICD patients. Early findings suggest a high burden of cognitive and psychological impairment, poor communication with providers, and frequent shocks at the end of life. These findings will inform the design of a larger cohort study designed to further explore the experiences of living and dying with an ICD in this important patient population.
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    Postmarket Surveillance of Medical Devices: A Comparison of Strategies in the US, EU, Japan, and China
    (Public Library of Science, 2013) Kramer, Daniel; Tan, Yongtian T.; Sato, Chiaki; Kesselheim, Aaron
    Daniel Kramer and colleagues compare strategies for postmarket surveillance of medical devices and discuss ways to improve these systems. Please see later in the article for the Editors' Summary
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    Transvenous Implantable Cardioverter‐Defibrillator (ICD) Lead Performance: A Meta‐Analysis of Observational Studies
    (John Wiley and Sons Inc., 2015) Providência, Rui; Kramer, Daniel; Pimenta, Dominic; Babu, Girish G.; Hatfield, Laura; Ioannou, Adam; Novak, Jan; Hauser, Robert G.; Lambiase, Pier D.
    Background: Despite the widespread use of implantable cardioverter‐defibrillators (ICDs) in clinical practice, concerns exist regarding ICD lead durability. The performance of specific lead designs and factors determining this in large populations need clarification. Methods and Results: The Medline, Embase, and Cochrane Collaboration databases were searched for studies including ≥2 of the most commonly implanted leads. The Mantel‐Haenszel random‐effects model was used. Seventeen studies were selected, including a total of 49 871 patients—5538 implanted with Durata (St. Jude Medical Inc), 10 605 with Endotak Reliance (Boston Scientific), 16 119 with Sprint Quattro (Medtronic Corp), 11 709 with Sprint Fidelis (Medtronic Corp), and 5900 with Riata (St. Jude Medical Inc)—with follow‐up of 136 509 lead‐years. Although the Durata lead presented a numerically higher rate, no statistically significant differences in the mean incidence of lead failure (0.29%–0.45% per year) were observed in comparison of the 3 nonrecalled leads. A higher event rate was documented with the Riata (1.0% per‐year increase) and Sprint Fidelis (>2.0% per‐year increase) leads compared with nonrecalled leads. An indication of increased incidence of Durata lead failure versus Sprint Quattro and Endotak Reliance leads was observed in 1 of 3 included studies, allowing for comparison of purely electrical lead failure, but this requires further evaluation. Conclusions: Endotak Reliance (8F), Sprint Quattro (8F), and Durata (7F) leads displayed low annual incidence of failure; however, long‐term follow‐up data are still scarce. More data are needed to clarify the performance and safety of the Durata lead.
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    Hospice Use Following Implantable Cardioverter-Defibrillator Implantation in Older Patients: Results From the National Cardiovascular Data Registry
    (Lippincott Williams & Wilkins, 2016) Kramer, Daniel; Reynolds, Matthew R.; Normand, Sharon-Lise; Parzynski, Craig S.; Spertus, John A.; Mor, Vincent; Mitchell, Susan
    Background— Older recipients of implantable cardioverter-defibrillators (ICDs) are at increased risk for short-term mortality in comparison with younger patients. Although hospice use is common among decedents aged >65, its use among older ICD recipients is unknown. Methods and Results— Medicare patients aged >65 matched to data in the National Cardiovascular Data Registry – ICD Registry from January 1, 2006 to March 31, 2010 were eligible for analysis (N=194 969). The proportion of ICD recipients enrolled in hospice, cumulative incidence of hospice admission, and factors associated with time to hospice enrollment were evaluated. Five years after device implantation, 50.9% of patients were either deceased or in hospice. Among decedents, 36.8% received hospice services. The cumulative incidence of hospice enrollment, accounting for the competing risk of death, was 4.7% (95% confidence interval [CI], 4.6%–4.8%) within 1 year and 21.3% (95% CI, 20.7%–21.8%) at 5 years. Factors most strongly associated with shorter time to hospice enrollment were older age (adjusted hazard ratio, 1.77; 95% CI, 1.73–1.81), class IV heart failure (versus class I; adjusted hazard ratio, 1.79; 95% CI, 1.66–1.94); ejection fraction <20 (adjusted hazard ratio, 1.57; 95% CI, 1.48–1.67), and greater hospice use among decedents in the patients’ health referral region. Conclusions— More than one-third of older patients dying with ICDs receive hospice care. Five years after implantation, half of older ICD recipients are either dead or in hospice. Hospice providers should be prepared for ICD patients, whose clinical trajectories and broader palliative care needs require greater focus.
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    Geographic and Temporal Variation in Cardiac Implanted Electric Devices to Treat Heart Failure
    (John Wiley and Sons Inc., 2016) Hatfield, Laura; Kramer, Daniel; Volya, Margaret; Reynolds, Matthew R.; Normand, Sharon‐Lise T.
    Background: Cardiac implantable electric devices are commonly used to treat heart failure. Little is known about temporal and geographic variation in use of cardiac resynchronization therapy (CRT) devices in usual care settings. Methods and Results: We identified new CRT with pacemaker (CRT‐P) or defibrillator generators (CRT‐D) implanted between 2008 and 2013 in the United States from a commercial claims database. For each implant, we characterized prior medication use, comorbidities, and geography. Among 17 780 patients with CRT devices (median age 69, 31% women), CRT‐Ps were a small and increasing share of CRT devices, growing from 12% to 20% in this study period. Compared to CRT‐D recipients, CRT‐P recipients were older (median age 76 versus 67), and more likely to be female (40% versus 30%). Pre‐implant use of β‐blockers and angiotensin‐converting enzyme inhibitors or angiotensin II receptor blockers was low in both CRT‐D (46%) and CRT‐P (31%) patients. The fraction of CRT‐P devices among all new implants varied widely across states. Compared to the increasing national trend, the share of CRT‐P implants was relatively increasing in Kansas and relatively decreasing in Minnesota and Oregon. Conclusions: In this large, contemporary heart failure population, CRT‐D use dwarfed CRT‐P, though the latter nearly doubled over 6 years. Practice patterns vary substantially across states and over time. Medical therapy appears suboptimal in real‐world practice.
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    Security and Privacy Qualities of Medical Devices: An Analysis of FDA Postmarket Surveillance
    (Public Library of Science, 2012) Kramer, Daniel; Baker, Matthew; Ransford, Benjamin; Molina-Markham, Andres; Stewart, Quinn; Fu, Kevin; Reynolds, Matthew R.
    Background: Medical devices increasingly depend on computing functions such as wireless communication and Internet connectivity for software-based control of therapies and network-based transmission of patients’ stored medical information. These computing capabilities introduce security and privacy risks, yet little is known about the prevalence of such risks within the clinical setting. Methods: We used three comprehensive, publicly available databases maintained by the Food and Drug Administration (FDA) to evaluate recalls and adverse events related to security and privacy risks of medical devices. Results: Review of weekly enforcement reports identified 1,845 recalls; 605 (32.8%) of these included computers, 35 (1.9%) stored patient data, and 31 (1.7%) were capable of wireless communication. Searches of databases specific to recalls and adverse events identified only one event with a specific connection to security or privacy. Software-related recalls were relatively common, and most (81.8%) mentioned the possibility of upgrades, though only half of these provided specific instructions for the update mechanism. Conclusions: Our review of recalls and adverse events from federal government databases reveals sharp inconsistencies with databases at individual providers with respect to security and privacy risks. Recalls related to software may increase security risks because of unprotected update and correction mechanisms. To detect signals of security and privacy problems that adversely affect public health, federal postmarket surveillance strategies should rethink how to effectively and efficiently collect data on security and privacy problems in devices that increasingly depend on computing systems susceptible to malware.
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    How Does Medical Device Regulation Perform in the United States and the European Union? A Systematic Review
    (Public Library of Science, 2012) Kramer, Daniel; Xu, Shuai; Kesselheim, Aaron
    Background: Policymakers and regulators in the United States (US) and the European Union (EU) are weighing reforms to their medical device approval and post-market surveillance systems. Data may be available that identify strengths and weakness of the approaches to medical device regulation in these settings. Methods and Findings: We performed a systematic review to find empirical studies evaluating medical device regulation in the US or EU. We searched Medline using two nested categories that included medical devices and glossary terms attributable to the US Food and Drug Administration and the EU, following PRISMA guidelines for systematic reviews. We supplemented this search with a review of the US Government Accountability Office online database for reports on US Food and Drug Administration device regulation, consultations with local experts in the field, manual reference mining of selected articles, and Google searches using the same key terms used in the Medline search. We found studies of premarket evaluation and timing (n = 9), studies of device recalls (n = 8), and surveys of device manufacturers (n = 3). These studies provide evidence of quality problems in pre-market submissions in the US, provide conflicting views of device safety based largely on recall data, and relay perceptions of some industry leaders from self-surveys. Conclusions: Few studies have quantitatively assessed medical device regulation in either the US or EU. Existing studies of US and EU device approval and post-market evaluation performance suggest that policy reforms are necessary for both systems, including improving classification of devices in the US and promoting transparency and post-market oversight in the EU. Assessment of regulatory performance in both settings is limited by lack of data on post-approval safety outcomes. Changes to these device approval and post-marketing systems must be accompanied by ongoing research to ensure that there is better assessment of what works in either setting.