Publications by Year: 2013

2013

Yang, Wu, Thomas Dietz, Daniel Boyd Kramer, Xiaodong Chen, and Jianguo Liu. (2013) 2013. “Going Beyond the Millennium Ecosystem Assessment: An Index System of Human Well-Being.”. PloS One 8 (5): e64582. https://doi.org/10.1371/journal.pone.0064582.

Understanding the linkages between ecosystem services (ES) and human well-being (HWB) is crucial to sustain the flow of ES for HWB. The Millennium Ecosystem Assessment (MA) provided a state-of-the-art synthesis of such knowledge. However, due to the complexity of the linkages between ES and HWB, there are still many knowledge gaps, and in particular a lack of quantitative indicators and integrated models based on the MA framework. To fill some of these research needs, we developed a quantitative index system to measure HWB, and assessed the impacts of an external driver–the 2008 Wenchuan Earthquake–on HWB. Our results suggest that our proposed index system of HWB is well-designed, valid and could be useful for better understanding the linkages between ES and HWB. The earthquake significantly affected households' well-being in our demonstration sites. Such impacts differed across space and across the five dimensions of the sub-index (i.e., the basic material for good life, security, health, good social relations, and freedom of choice and action). Since the conceptual framework is based on the generalizable MA framework, our methods should also be applicable to other study areas.

Abdelhadi, Raed H, Samir F Saba, Christopher R Ellis, Pamela K Mason, Daniel B Kramer, Paul A Friedman, Melanie T Gura, et al. (2013) 2013. “Independent Multicenter Study of Riata and Riata ST Implantable Cardioverter-Defibrillator Leads.”. Heart Rhythm 10 (3): 361-5. https://doi.org/10.1016/j.hrthm.2012.10.045.

BACKGROUND: Riata and Riata ST leads (St Jude Medical, Sylmar, CA) are prone to failure. There are no independent multicenter reports regarding Riata or Riata ST lead performance.

OBJECTIVE: To conduct a retrospective multicenter study of Riata and Riata ST leads that were implanted and followed at 7 centers.

METHODS: The study included adults who received St Jude Medical Riata or Riata ST leads. Data for Quattro Secure leads were obtained from an earlier study.

RESULTS: From 2002 to 2010, 1081 patients received a Riata (n = 774) or Riata ST (n = 307) lead. Follow-up was longer for Riata than Riata ST leads (4.2 ± 2.4 years vs 3.3 ± 1.7 years; P<.0001). During the study, 67 leads failed (6.2%), including 62 of 774 Riata (8.0%) and 5 of 307 Riata ST (1.6%) leads. Forty-seven of 67 lead failures (70.1%) were caused by electrical malfunction, and 20 lead failures (29.9%) were due to externalized conductors (ECs) that were electrically intact. Of 110 leads examined fluoroscopically, ECs were found in 26 of 81 Riata (32%) and 1 of 29 Riata ST (3.4%) leads. Of 26 Riata leads with ECs, 7 (27%) were malfunctioning. Riata leads had lower overall and malfunction free survival compared to Quattro leads (P<.0001), while Riata ST lead survival was not different (P = .422).

CONCLUSIONS: The survival of Riata (but not Riata ST) leads was lower than Quattro leads; however, Riata ST leads had significantly shorter follow-up than Riata leads. ECs were common in Riata leads, and more than a quarter of Riata leads that had ECs were malfunctioning. Our observations suggest that systematic fluoroscopic examination of patients with Riata leads is appropriate.

Kramer, Daniel B, Matthew R Reynolds, and Susan L Mitchell. (2013) 2013. “Resynchronization: Considering Device-Based Cardiac Therapy in Older Adults.”. Journal of the American Geriatrics Society 61 (4): 615-21. https://doi.org/10.1111/jgs.12174.

Cardiac resynchronization therapy (CRT) is a device-based treatment available to select individuals with systolic heart failure (HF), a large proportion of whom are aged 65 and older. As the field of CRT advances, together with shifting demographics and expanded indications for implantation, there is a need for practitioners caring for older adults to understand what is and is not known about the use of CRT specifically in this population. Clinical trials demonstrating benefits for severe and mild HF have uncertain generalizability to older adults. Other studies demonstrate that device-related complications may be more common with CRT than with simpler devices and more common in older adults. CRT clinical trials also may not adequately capture outcomes and concerns specific to older adults, including quality of life and end-of-life care experiences. Informed decision-making by clinicians, policy-makers, and patients will require greater understanding of the use and outcomes of CRT in older persons.

Kramer, Daniel B, Yongtian T Tan, Chiaki Sato, and Aaron S Kesselheim. (2013) 2013. “Postmarket Surveillance of Medical Devices: A Comparison of Strategies in the US, EU, Japan, and China.”. PLoS Medicine 10 (9): e1001519. https://doi.org/10.1371/journal.pmed.1001519.

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

Fein, Adam S, Alexei Shvilkin, Dhaval Shah, Charles I Haffajee, Saumya Das, Kapil Kumar, Daniel B Kramer, et al. (2013) 2013. “Treatment of Obstructive Sleep Apnea Reduces the Risk of Atrial Fibrillation Recurrence After Catheter Ablation.”. Journal of the American College of Cardiology 62 (4): 300-5. https://doi.org/10.1016/j.jacc.2013.03.052.

OBJECTIVES: The aim of this study was to examine the effect of continuous positive airway pressure (CPAP) therapy on atrial fibrillation (AF) recurrence in patients with obstructive sleep apnea (OSA) undergoing pulmonary vein isolation (PVI).

BACKGROUND: OSA is a predictor of AF recurrence following PVI. However, the impact of CPAP therapy on PVI outcome in patients with OSA is poorly known.

METHODS: Among 426 patients who underwent PVI between 2007 and 2010, 62 patients had a polysomnography-confirmed diagnosis of OSA. While 32 patients were "CPAP users" the remaining 30 patients were "CPAP nonusers." The recurrence of any atrial tachyarrhythmia, use of antiarrhythmic drugs, and need for repeat ablations were compared between the groups during a follow-up period of 12 months. Additionally, the outcome of patients with OSA was compared to a group of patients from the same PVI cohort without OSA.

RESULTS: CPAP therapy resulted in higher AF-free survival rate (71.9% vs. 36.7%; p = 0.01) and AF-free survival off antiarrhythmic drugs or repeat ablation following PVI (65.6% vs. 33.3%; p = 0.02). AF recurrence rate of CPAP-treated patients was similar to a group of patients without OSA (HR: 0.7, p = 0.46). AF recurrence following PVI in CPAP nonuser patients was significantly higher (HR: 2.4, p < 0.02) and similar to that of OSA patients managed medically without ablation (HR: 2.1, p = 0.68).

CONCLUSIONS: CPAP is an important therapy in OSA patients undergoing PVI that improves arrhythmia free survival. PVI offers limited value to OSA patients not treated with CPAP.

Kramer, Daniel B, Kevin F Kennedy, Peter A Noseworthy, Alfred E Buxton, Mark E Josephson, Sharon-Lise Normand, John A Spertus, Peter J Zimetbaum, Matthew R Reynolds, and Susan L Mitchell. (2013) 2013. “Characteristics and Outcomes of Patients Receiving New and Replacement Implantable Cardioverter-Defibrillators: Results from the NCDR.”. Circulation. Cardiovascular Quality and Outcomes 6 (4): 488-97. https://doi.org/10.1161/CIRCOUTCOMES.111.000054.

BACKGROUND: Little is known about the clinical features, procedural risks, or survival of patients receiving replacement versus new implantable cardioverter-defibrillators (ICDs).

METHODS AND RESULTS: Entries in the National Cardiovascular Data Registry (NCDR) ICD Registry from 2005 through 2010 were eligible for inclusion (n=463,978). Baseline demographic data, clinical information, and procedural variables were compared between patients receiving new (n=359,993; 77.6%) and replacement (n=103,985; 22.4%) ICDs and entered into a propensity match model to determine adjusted survival rates. Patients receiving replacement ICDs were older (70.7 versus 67.5 years of age) and more likely to have atrial fibrillation (41.8% versus 31.4%; P<0.001) and ventricular tachycardia (60.5% versus 33.9%; P<0.001) compared with patients receiving new ICDs. Median battery life was only 4.6 years (25%-75% interquartile range, 3.7-5.8) for all replaced devices, 5.8 (25%-75% interquartile range, 4.2-7.5) for single-chamber, 5.1 (25%-75% interquartile range, 4.1-6.1) for dual-chamber, and 3.9 (25%-75% interquartile range, 3.2-4.6) years for biventricular devices. Patients receiving replacement ICDs had lower rates of index admission complications (0.9% versus 3.2%; P<0.001) but greater risk for death compared receiving patients receiving new ICDs in unadjusted analysis (hazard ratio, 1.18; 95% confidence interval, 1.16-1.20; P<0.0001) and after propensity-score matching (hazard ratio, 1.28; 95% confidence interval, 1.25-1.30; P<0.0001).

CONCLUSIONS: Patients receiving replacement ICDs are older and at greater risk for death compared with those receiving initial ICD implants. The battery life of initial ICDs is shorter than previously reported.