Publications

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.

BACKGROUND: Current guidelines do not recommend implantable cardioverter-defibrillator (ICD) implantation in patients with a life expectancy of <1 year. Better methods are needed for identifying patients at high risk for early mortality despite ICD therapy.

OBJECTIVE: To develop and validate a risk prediction score to identify patients at high risk for death within 1 year despite ICD therapy.

DESIGN: Detailed clinical data were collected on a large observational cohort of ICD patients from 3 tertiary care centers. One-third of the patients were randomly selected to form the prediction group (PG) from which a risk score was developed using logistic regression. This score was then applied to the remaining two-thirds of the cohort (validation group [VG]) to assess the risk score's predictive accuracy.

RESULTS: The total cohort included 2717 ICD patients (mean age = 64.6 ± 14.5, male = 77.2%, primary prevention = 74.7%). A simple risk score incorporating peripheral arterial disease, age ≥ 70 years, creatinine ≥ 2.0 mg/dL, and ejection fraction ≤20% (PACE) accurately predicted 1-year mortality in the VG. Patients with a risk score of ≥3 had a >4-fold excess 1-year mortality compared with patients with a risk score of <3 (16.5% vs 3.5%; P <.0001).

LIMITATION: Risk reduction provided by ICD therapy in this cohort is not known given the lack of a control group.

CONCLUSIONS: A simple risk score accurately predicts 1-year mortality in ICD patients, as patients with a PACE risk score of ≥3 are at high risk despite ICD therapy.

BACKGROUND: While surgical epicardial lead placement is performed in a subset of cardiac resynchronization therapy patients, data comparing survival following surgical versus transvenous lead placement are limited. We hypothesized that surgical procedures would be associated with increased mortality risk.

METHODS: Long-term event-free survival was assessed for 480 consecutive patients undergoing surgical (48) or percutaneous (432) left ventricle (LV) lead placement at our institution from January 2000 to September 2008.

RESULTS: Baseline clinical and demographic characteristics were similar between groups. While there was no statistically significant difference in overall event-free survival (P = 0.13), when analysis was restricted to surgical patients with isolated surgical lead placement (n = 28), event-free survival was significantly lower in surgical patients (P = 0.015). There appeared to be an early risk (first approximately 3 months postimplantation) with surgical lead placement, primarily in LV lead-only patients. Event rates were significantly higher in LV lead-only surgical patients than in transvenous patients in the first 3 months (P = 0.006). In proportional hazards analysis comparing isolated surgical LV lead placement to transvenous lead placement, adjusted hazard ratios were 1.8 ([1.1,2.7] P = 0.02) and 1.3 ([1.0,1.7] P = 0.07) for the first 3 months and for the full duration of follow-up, respectively.

CONCLUSIONS: Isolated surgical LV lead placement appears to carry a small but significant upfront mortality cost, with risk extending beyond the immediate postoperative period. Long-term survival is similar, suggesting those surviving beyond this period of early risk derive the same benefit as coronary sinus lead recipients. Further work is needed to identify risk factors associated with early mortality following surgical lead placement.

PURPOSE: This study aims to identify nurses' concerns about the clinical, ethical, and legal aspects of deactivating cardiovascular implantable electronic devices (CIEDs).

METHODS: We used focus groups to discuss decision making in CIED management.

RESULTS: Fourteen nurses described the informed consent process as overly focused on procedures, with inadequate coverage of living with a device (e.g., infection risks and device shocks). Elderly patients were especially vulnerable to physician or family pressure about CIED implantation. Nurses believed that initial advance care planning discussions were infrequent and rarely revisited when health status changed. Many patients did not know that CIEDs could be deactivated; it was often addressed reactively (i.e., after multiple shocks) or when patients became too ill to participate in decision making. Nurses generally were supportive of CIED deactivation when it was requested by a well-informed patient. However, nurses distinguished between withholding versus withdrawing treatment (i.e., turning off CIEDs vs. declining implantation). Although most patients viewed their device as lifesaving, others perceived them as a "ticking time bomb."

CONCLUSIONS: Nurses identified concerns about CIED decision making from implantation through end-of-life care and device deactivation and suggested avenues for improving patient care including early and regular advance care planning.

A device interrogation for a 32-year-old woman with arrhythmogenic right ventricular cardiomyopathy and an implantable cardioverter-defibrillator capable of monitoring intrathoracic impedance demonstrated a dramatic increase in her OptiVol Fluid index levels in the absence of clinical heart failure. The timing of her intrathoracic impedance changes correlated with plasma volume changes during an uneventful pregnancy without cardiovascular complications. The strengths and limitations of intrathoracic impedance are described in the context of the physiology of pregnancy.

Little is known about patients' views surrounding the ethical and legal aspects of managing pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs) near the end of life. Patients with hypertrophic cardiomyopathy (HC) are at heightened risk of sudden cardiac death and are common recipients of such devices. Patients with HC recruited from the membership of the Hypertrophic Cardiomyopathy Association were surveyed about their clinical histories, advance care planning, legal knowledge, and ethical beliefs relating to the withdrawal of PM and ICD therapy. The mean age of the 546 patients was 49.1 years, 47% were women, and 57% had ICDs. Only 46% of the respondents had completed an advance directive, only 51% had a healthcare proxy, and cardiac implantable electrical devices (CIEDs) were commonly not addressed in either (92% and 58%, respectively). Many patients characterized deactivating PMs or ICDs as euthanasia or physician-assisted suicide (29% for PMs and 17% for ICDs), and >50% expressed uncertainty regarding the legality of device deactivation. Patients viewed deactivation of ICDs and PMs as morally different from other life-sustaining therapies such as mechanical ventilation and dialysis, and these views varied substantially according to the CIED type (p <0.0001). The respondents expressed concerns regarding clinical conflicts related to religion, ethical and legal uncertainty, and informed consent. In conclusion, patients who have, or are eligible to receive, CIEDs might require improved advance care planning and education regarding the ethical and legal options for managing CIEDs at the end of life.