Faculty Bibliography

Patients with a durable, continuous-flow left ventricular assist device (LVAD) are commonly prescribed the combination of an oral anticoagulant and an oral antiplatelet agent as prophylaxis against device thrombosis and systemic embolic events. Current International Society of Heart and Lung (ISHLT) guidelines recommend warfarin with an INR goal of 2-3 and concomitant aspirin 81-325 mg daily for patients with a HeartMate II LVAD. Unfortunately, gastrointestinal (GI) bleeding is very common in these patients because of multiple factors including the development of arteriovenous malformations and acquired von Willebrand syndrome. If this bleeding cannot be corrected through interventional measures, it then requires at least temporary, and potentially permanent, cessation of antiplatelet or anticoagulant therapy. Patients who continue to bleed while off all antithrombotic therapies present a clinical challenge. We describe the successful management of a patient with refractory GI bleeding through the use of inhaled desmopressin.

BACKGROUND:Early right-sided heart failure (RHF) after left ventricular assist device (LVAD) implantation is associated with increased mortality, but little is known about patients who develop late RHF (LRHF). We evaluated the incidence, risk factors, and clinical impact of LRHF in patients supported by axial-flow LVADs. METHODS:Data were analyzed from 537 patients enrolled in the HeartMate II (HM II; Thoratec/St. Jude) destination therapy clinical trial. LRHF was defined as the development of clinical RHF accompanied by the need for inotropic support occurring more than 30 days after discharge from the index LVAD implant hospitalization. Clinical variables, quality of life, rehospitalizations, and survival were compared between patients with and without LRHF. RESULTS:LRHF developed in 41 patients (8%), with a median time to LRHF of 480 days. A higher preoperative blood urea nitrogen and increased central venous pressure-to-pulmonary capillary wedge pressure ratio were independent predictors of LRHF. The Michigan and HMII RHF risk scores were both associated with an increased likelihood of LRHF (p < 0.05). Patients with LRHF had worse quality of life according to the Kansas City Cardiomyopathy Questionnaire (61 ± 26 vs 70 ± 21; p < 0.05), poorer functional capacity by 6-minute walk distance (275 ± 189 m vs 312 ± 216 m; p < 0.05), and more rehospitalizations (6 vs 3; p < 0.001). LRHF was associated with decreased survival (p < 0.001). CONCLUSIONS:LRHF is an important complication in patients with LVADs and is associated with worse quality of life, reduced functional capacity, more frequent hospitalizations, and worse survival compared with those without LRHF.

BACKGROUND:Recommended structured clinical practices including implant technique, anti-coagulation strategy, and pump speed management (PREVENT [PREVENtion of HeartMate II Pump Thrombosis Through Clinical Management] recommendations) were developed to address risk of early (<3 months) pump thrombosis (PT) risk with HeartMate II (HMII; St. Jude Medical, Inc. [Thoratec Corporation], Pleasanton, CA). We prospectively assessed the HMII PT rate in the current era when participating centers adhered to the PREVENT recommendations. METHODS:PREVENT was a prospective, multi-center, single-arm, non-randomized study of 300 patients implanted with HMII at 24 participating sites. Confirmed PT (any suspected PT confirmed visually and/or adjudicated by an independent assessor) was evaluated at 3 months (primary end-point) and at 6 months after implantation. RESULTS:The population included 83% men (age 57 years ± 13), 78% destination therapy, and 83% Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profile 1-3. Primary end-point analysis showed a confirmed PT of 2.9% at 3 months and 4.8% at 6 months. Adherence to key recommendations included 78% to surgical recommendations, 95% to heparin bridging, and 79% to pump speeds ≥9,000 RPMs (92% >8,600 RPMs). Full adherence to implant techniques, heparin bridging, and pump speeds ≥9,000 RPMs resulted in a significantly lower risk of PT (1.9% vs 8.9%; p < 0.01) and lower composite risk of suspected thrombosis, hemolysis, and ischemic stroke (5.7% vs 17.7%; p < 0.01) at 6 months. CONCLUSIONS:Adoption of all components of a structured surgical implant technique and clinical management strategy (PREVENT recommendations) is associated with low rates of confirmed PT.

Acquired von Willebrand disease increases bleeding risk in patients implanted with a continuous-flow left ventricular assist device. Lower aspirin (ASA) doses decrease the risk of bleeding without an increased risk of embolic events. No published studies in the United States have compared the incidence of bleeding and thrombotic events between antithrombotic regimens with and without ASA. A single-center, retrospective analysis was conducted of adult patients implanted with a HeartMate II (HM II). Patients received warfarin and ASA 81 mg daily or warfarin alone. The primary end-point was a composite of death, bleeding events, and thrombotic events from the date of HM II implantation to first event or 18 months. Secondary end-points included the individual components of the primary end-point and the proportion of patients alive with HM II or transplanted. The Wilcoxon rank sum test and Fisher's exact test were used for statistical analysis. Of the 76 patients meeting inclusion criteria, 44 received warfarin and ASA and 32 received warfarin alone. Baseline characteristics were similar between groups. Warfarin alone was not associated with an increased risk of the primary composite outcome (53 vs. 59%, respectively, p = 0.64). No significant difference was observed in any bleeding event (34 vs. 43%, respectively, p = 0.48) nor any thrombotic event (9 vs. 11%, respectively, p = 1.00) with warfarin alone compared with warfarin and ASA. Elimination of antiplatelet therapy from the HM II antithrombotic regimen was associated with no significant difference in the composite outcome of bleeding events, thrombotic events, or death, nor the individual components of each end-point.

BACKGROUND:Organizational models in the intensive care unit (ICU) have classically been described as either closed or open, depending on the presence or absence of a dedicated ICU team. Although a closed model has been shown to improve patient outcomes in medical and surgical ICUs, the merits of various care models have not been previously explored in the cardiac ICU (CICU) setting. METHODS:From November 2012 to March 2014, data were prospectively collected on all admissions before and after transition from an open to closed CICU at our institution. Baseline clinical variables, illness severity, admission and discharge diagnoses, resource use, and outcomes were recorded. Anonymous surveys were also collected from nursing and resident trainee participants to evaluate the influence of unit structure on perceptions of care. Descriptive statistics were used, and logistic regression modeling was performed to examine the impact of unit structure on mortality. RESULTS:The study consisted of 670 patients, 332 (49.6%) of whom were admitted to the open CICU model and 338 (50.4%) of whom were admitted to the closed model. Neither CICU nor hospital mortality differed between the open and closed units, though length of stay was shorter in the closed CICU. Additionally, nurses and resident trainees reported that the closed CICU allowed for better communication, collaboration, and education. CONCLUSIONS:Although there was no significant impact of unit structure on patient outcomes in this single-center study, the closed CICU model was associated with better perceptions of care.

Cardiogenic shock is a high-acuity, potentially complex, and hemodynamically diverse state of end-organ hypoperfusion that is frequently associated with multisystem organ failure. Despite improving survival in recent years, patient morbidity and mortality remain high, and there are few evidence-based therapeutic interventions known to clearly improve patient outcomes. This scientific statement on cardiogenic shock summarizes the epidemiology, pathophysiology, causes, and outcomes of cardiogenic shock; reviews contemporary best medical, surgical, mechanical circulatory support, and palliative care practices; advocates for the development of regionalized systems of care; and outlines future research priorities.

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.