Faculty Bibliography

The cardiac intensive care unit (CICU) has changed considerably over time and now serves a unique patient population with a high burden of cardiovascular and noncardiovascular critical illness. Patient complexity and technological evolutions in the CICU have catalyzed the development of critical care cardiology, a fledgling discipline that combines specialization in cardiovascular diseases with knowledge and experience in critical care medicine. Numerous uncertainties and challenges threaten to stymie the growth of this field. A multidisciplinary dialogue focused on the best care design for the CICU patient is needed as we consider alternative approaches to clinical training, staffing, and investigation in this rapidly evolving arena.

BACKGROUND:Clinical practice guidelines recommend admitting patients with stable non-ST-segment elevation acute coronary syndrome (NSTE ACS) to telemetry units, yet up to two-thirds of patients are admitted to higher-acuity critical care units (CCUs). The outcomes of patients with stable NSTE ACS initially admitted to a CCU vs a cardiology ward with telemetry have not been described. METHODS:We used population-based data of 7,869 patients hospitalized with NSTE ACS admitted to hospitals in Alberta, Canada, between April 1, 2007, and March 31, 2013. We compared outcomes among patients initially admitted to a CCU (n=5,141) with those admitted to cardiology telemetry wards (n=2,728). RESULTS:Patients admitted to cardiology telemetry wards were older (median 69 vs 65years, P<.001) and more likely to be female (37.2% vs 32.1%, P<.001) and have a prior myocardial infarction (14.3% vs 11.5%, P<.001) compared with patients admitted to a CCU. Patients admitted directly to cardiology telemetry wards had similar hospital stays (6.2 vs 5.7days, P=.29) and fewer cardiac procedures (40.3% vs 48.5%, P<.001) compared with patients initially admitted to CCUs. There were no differences in the frequency of in-hospital mortality (1.3% vs 1.2%, adjusted odds ratio [aOR] 1.57, 95% CI 0.98-2.52), cardiac arrest (0.7% vs 0.9%, aOR 1.37, 95% CI 0.94-2.00), 30-day all-cause mortality (1.6% vs 1.5%, aOR 1.50, 95% CI 0.82-2.75), or 30-day all-cause postdischarge readmission (10.6% vs 10.8%, aOR 1.07, 95% CI 0.90-1.28) between cardiology telemetry ward and CCU patients. Results were similar across low-, intermediate-, and high-risk Duke Jeopardy Scores, and in patients with non-ST-segment myocardial infarction or unstable angina. CONCLUSIONS:There were no differences in clinical outcomes observed between patients with NSTE ACS initially admitted to a ward or a CCU. These findings suggest that stable NSTE ACS may be managed appropriately on telemetry wards and presents an opportunity to reduce hospital costs and critical care capacity strain.

RATIONALE/BACKGROUND:Limitations in methods for the rapid diagnosis of hospital-acquired infections often delay initiation of effective antimicrobial therapy. New diagnostic approaches offer potential clinical and cost-related improvements in the management of these infections. OBJECTIVES/OBJECTIVE:We developed a decision modeling framework to assess the potential cost-effectiveness of a rapid biomarker assay to identify hospital-acquired infection in high-risk patients earlier than standard diagnostic testing. METHODS:The framework includes parameters representing rates of infection, rates of delayed appropriate therapy, and impact of delayed therapy on mortality, along with assumptions about diagnostic test characteristics and their impact on delayed therapy and length of stay. Parameter estimates were based on contemporary, published studies and supplemented with data from a four-site, observational, clinical study. Extensive sensitivity analyses were performed. The base-case analysis assumed 17.6% of ventilated patients and 11.2% of nonventilated patients develop hospital-acquired infection and that 28.7% of patients with hospital-acquired infection experience delays in appropriate antibiotic therapy with standard care. We assumed this percentage decreased by 50% (to 14.4%) among patients with true-positive results and increased by 50% (to 43.1%) among patients with false-negative results using a hypothetical biomarker assay. Cost of testing was set at $110/d. MEASUREMENTS AND MAIN RESULTS/RESULTS:In the base-case analysis, among ventilated patients, daily diagnostic testing starting on admission reduced inpatient mortality from 12.3 to 11.9% and increased mean costs by $1,640 per patient, resulting in an incremental cost-effectiveness ratio of $21,389 per life-year saved. Among nonventilated patients, inpatient mortality decreased from 7.3 to 7.1% and costs increased by $1,381 with diagnostic testing. The resulting incremental cost-effectiveness ratio was $42,325 per life-year saved. Threshold analyses revealed the probabilities of developing hospital-acquired infection in ventilated and nonventilated patients could be as low as 8.4 and 9.8%, respectively, to maintain incremental cost-effectiveness ratios less than $50,000 per life-year saved. CONCLUSIONS:Development and use of serial diagnostic testing that reduces the proportion of patients with delays in appropriate antibiotic therapy for hospital-acquired infections could reduce inpatient mortality. The model presented here offers a cost-effectiveness framework for future test development.

PURPOSE/OBJECTIVE:Patients with acute myocardial infarction (AMI) and respiratory impairment may be treated with either invasive or non-invasive mechanical ventilation (MV). However, there has been little testing of non-invasive MV in the setting of AMI. Our objective was to evaluate the incidence and associated clinical outcomes of patients with AMI who were treated with non-invasive or invasive MV. METHODS:This was a retrospective observational study in which consecutive patients with AMI (n = 1610) were enrolled. The association between exclusively non-invasive MV, invasive MV and outcomes was assessed by multivariable models. RESULTS:Mechanical ventilation was used in 293 patients (54% invasive and 46% exclusively non-invasive). In-hospital mortality rates for patients without MV, with exclusively non-invasive MV, and with invasive MV were 4.0%, 8.8%, and 39.5%, respectively (P<0.001). The median lengths of hospital stay were 6 (5.8-6.2), 13 (11.2-4.7), and 28 (18.0-37.9) days, respectively (P<0.001). Exclusively non-invasive MV was not associated with in-hospital death (adjusted HR = 0.90, 95% CI 0.40-1.99, P = 0.79). Invasive MV was strongly associated with a higher risk of in-hospital death (adjusted HR = 3.07, 95% CI 1.79-5.26, P<0.001). CONCLUSIONS:In AMI setting, 18% of the patients required MV. Almost half of these patients were treated with exclusively non-invasive strategies with a favorable prognosis, while patients who needed to be treated invasively had a three-fold increase in the risk of death. Future prospective randomized trials are needed to compare the effectiveness of invasive and non-invasive MV for the initial approach of respiratory failure in AMI patients.

BACKGROUND: Patients with bleeding complications during left ventricular assist device (LVAD) support often require a reduction in the recommended warfarin plus aspirin regimen. To characterize those who can be safely managed with a reduced anti-thrombotic strategy, the TRACE (STudy of Reduced Anti-Coagulation/Anti-platelEt Therapy in Patients with the HeartMate II LVAS) study was initiated in the United States (U.S.) and Europe. METHODS: The TRACE U.S. arm enrolled HeartMate II (HMII; Thoratec) outpatients on a regimen of reduced anti-thrombotic therapy (RT), defined as vitamin K antagonist (warfarin) only, aspirin only, or no anti-thrombotic agent. The indication for RT, changes in anti-thrombotic therapies, and patient outcomes after RT were documented. Results for patients reaching 12 months or outcome are presented here. RESULTS: Between April 2012 and June 2013, 100 HMII outpatients (85% men) on RT (median age 64.5 [interquartile range, 32, 82] years, 61% with ischemic etiology, 69% destination therapy) were enrolled from 9 U.S. sites. The primary reason for RT initiation was in response to a bleeding event (82%). Pharmacotherapy at RT initiation included warfarin only (38%), aspirin only (28%), or no anti-thrombotic agent (34%). Freedom from ischemic stroke at 1 year was 93.8% +/- 2.5%, and freedom from device thrombosis was 92.7% +/- 2.7%. Despite RT, a subsequent bleeding event occurred in 52%. CONCLUSIONS: Reducing anti-thrombotic therapies in response to bleeding among HMII patients was achievable but may be associated with a higher risk for device thrombosis. Furthermore, despite an RT strategy, bleeding often will persist in those prone to such events.

OBJECTIVE:Acute and chronic cardiovascular comorbidities are common among critically ill individuals. It is unclear if current critical care fellowship trainees feel adequately prepared to manage these conditions. DESIGN/METHODS:Prospective, cross-sectional survey. PATIENTS OR SUBJECTS/METHODS:Trainees enrolled in U.S. critical care training programs. SETTING/METHODS:Accredited pulmonary/critical care, surgery/critical care, anesthesiology/critical care, and stand-alone critical care training programs. INTERVENTIONS/METHODS:None. MEASUREMENTS AND MAIN RESULTS/RESULTS:A 19-item survey assessing trainee confidence in the management of cardiac critical illness and the performance of cardiac-specific critical care interventions was constructed using Accreditation Council for Graduate Medical Education recommendations as a reference. After validation, the survey was electronically sent to all training programs for dissemination to their trainees. Confidence scores were measured on a Likert scale from 1 to 5. A total of 134 completed surveys were analyzed. Overall, respondents reported lower confidence in managing cardiovascular compared with noncardiovascular diseases in the ICU (4.0 vs 4.6 out of 5). Likewise, they reported lower perceived competence in performing cardiovascular procedures specific to the ICU (2.9 vs 4.5 out of 5). The majority (88%) of those surveyed felt that they would benefit from increased didactic and clinical experience in the management of cardiovascular critical illness. CONCLUSIONS:Current critical care fellows may be unprepared to deal with the increasing prevalence of cardiovascular illness in the ICU. This potential educational gap warrants timely attention to ensure that future graduates have the requisite skills necessary to manage these critically ill patients and presents a unique opportunity to develop multidisciplinary partnerships for enhancing training.

BACKGROUND:Delirium is common in the medical and surgical intensive care unit (ICU), and its association with morbidity and mortality is well described. Despite emerging data, which have highlighted a growing critical care burden in the contemporary cardiac ICU (CICU), much less is known about delirium in this specialized setting. METHODS AND RESULTS/RESULTS:Records for consecutive CICU patients aged ≥18 years who were admitted to our academic, tertiary care institution from December 2012 to March 2014 for a primary cardiovascular diagnosis were reviewed. Only those with a documented Confusion Assessment Method for ICU score were included in the final analysis. Baseline characteristics, resource use, and outcomes were collected. Disease severity was assessed using the modified Acute Physiology and Chronic Health Evaluation II score and the Simplified Acute Physiology ScoreII. Multivariable logistic and linear regression models were constructed to evaluate the association between CICU delirium, length of stay, and death. Among 590 patients included, the prevalence of CICU delirium was 20.3%. Delirious patients were older, had greater disease severity, required longer ICU stays (5 vs 2 days; P < .001), and had higher mortality (27% vs 3%; P < .001). In the adjusted setting, delirium remained strongly associated with both increased mortality (P < .001) and length of stay (P = .001). CONCLUSIONS:In those with cardiac critical illness, delirium is common and associated with worse survival and greater resource consumption. Future study is needed to validate these findings and to develop effective strategies for the early identification and treatment of the delirious CICU patient.

BACKGROUND:Despite the beneficial effects of mechanical circulatory support (MCS), the majority of patients ultimately will have an adverse event. Although hemolysis is common among temporary devices, the incidence and clinical significance of hemolysis in patients managed with long-term, durable left ventricular assist device (LVAD) therapy is largely unknown. METHODS:Data were obtained from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). All adults who received a continuous-flow LVAD (CF-LVAD) between June 2006 and March 2012 were included. A hemolytic event was defined as a plasma-free hemoglobin >40 mg/dl in association with clinical signs of hemolysis occurring at least 72 hours after LVAD implant. Descriptive statistics, time-dependent analyses and multivariable modeling were employed for statistical purposes. RESULTS:A total of 4,850 patients followed for a mean of 11.1 months comprised the final study population. There were 340 hemolytic events in 260 patients. Freedom from hemolysis was 97% at 3 months, 94% at 1 year and 91% at 2 years. Mean time from implant to first hemolysis event was 7.4 months. Younger age (<60 years) was independently associated with greater hemolysis (p < 0.001). Thrombotic device malfunction, device exchange and mortality were all significantly higher after hemolysis, with the greatest risk for each occurring within 6 months. CONCLUSIONS:Hemolysis is not a rare event after CF-LVAD implantation and is associated with an early increase in morbidity and death. Future study should focus on other device and implant characteristics that may lead to hemolytic events, as well as appropriate strategies for managing affected patients.