Development and Usability Testing of a System to Detect Adverse Events and Medical Mistakes.

Many inpatient hospital visits result in adverse events, and a disproportionate number of adverse events are thought to occur among vulnerable populations. The personal and financial costs of these events are significant at the individual, care team, and system levels. Existing methods for identifying adverse events, such as the Institute for Healthcare Improvement Global Trigger Tool, typically involve retroactive chart review to identify risks or triggers and then detailed review to determine whether and what type of harm occurred. These methods are limited in scalability and ability to prospectively identify triggers to enable intervention before an adverse event occurs. The purpose of this study was to gather usability feedback on a prototype of an informatics intervention based on the IHI method. The prototype electronic Global Trigger Tool collects and presents risk factors for adverse events. Six health professionals identified as potential users in clinical, quality improvement, and research roles were interviewed. Interviewees universally described insufficiencies of current methods for tracking adverse events and offered important information on desired future user interface features. A key next step will be to refine and integrate an electronic Global Trigger Tool system into standards-compliant electronic health record systems as a patient safety module.

Government Regulation and Percutaneous Coronary Intervention Volume, Access and Outcomes: Insights From the Washington State Cardiac Care Outcomes Assessment Program.

Background It is unclear how to geographically distribute percutaneous coronary intervention (PCI) programs to optimize patient outcomes. The Washington State Certificate of Need program seeks to balance hospital volume and patient access through regulation of elective PCI. Methods and Results We performed a retrospective cohort study of all non-Veterans Affairs hospitals with PCI programs in Washington State from 2009 to 2018. Hospitals were classified as having (1) full PCI services and surgical backup (legacy hospitals, n=17); (2) full services without surgical backup (new certificate of need [CON] hospitals, n=9); or (3) only nonelective PCI without surgical backup (myocardial infarction [MI] access hospitals, n=9). Annual median hospital-level volumes were highest at legacy hospitals (605, interquartile range, 466-780), followed by new CON, (243, interquartile range, 146-287) and MI access, (61, interquartile range, 23-145). Compared with MI access hospitals, risk-adjusted mortality for nonelective patients was lower for legacy (odds ratio [OR], 0.59 [95% CI, 0.48-0.72]) and new-CON hospitals (OR, 0.55 [95% CI, 0.45-0.65]). Legacy hospitals provided access within 60 minutes for 90% of the population; addition of new CON and MI access hospitals resulted in only an additional 1.5% of the population having access within 60 minutes. Conclusions Many PCI programs in Washington State do not meet minimum volume standards despite regulation designed to consolidate elective PCI procedures. This CON strategy has resulted in a tiered system that includes low-volume centers treating high-risk patients with poor outcomes, without significant increase in geographic access. CON policies should re-evaluate the number and distribution of PCI programs.

Survival Probability and Survival Benefit Associated With Primary Prevention Implantable Cardioverter-Defibrillator Generator Changes.

Background As patients derive variable benefit from generator changes (GCs) of implantable cardioverter-defibrillators (ICDs) with an original primary prevention (PP) indication, better predictors of outcomes are needed. Methods and Results In the National Cardiovascular Data Registry ICD Registry, patients undergoing GCs of initial non-cardiac resynchronization therapy PP ICDs in 2012 to 2016, predictors of post-GC survival and survival benefit versus control heart failure patients without ICDs were assessed. These included predicted annual mortality based on the Seattle Heart Failure Model, left ventricular ejection fraction (LVEF) >35%, and the probability that a patient's death would be arrhythmic (proportional risk of arrhythmic death [PRAD]). In 40 933 patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs (age 67.7±12.0 years, 24.5% women, 34.1% with LVEF >35%), Seattle Heart Failure Model-predicted annual mortality had the greatest effect size for decreased post-GC survival (P<0.0001). Patients undergoing GCs of initial noncardiac resynchronization therapy PP ICDs with LVEF >35% had a lower Seattle Heart Failure Model-adjusted survival versus 23 472 control heart failure patients without ICDs (model interaction hazard ratio, 1.21 [95% CI, 1.11-1.31]). In patients undergoing GCs of initial noncardiac resynchonization therapy PP ICDs with LVEF ≤35%, the model indicated worse survival versus controls in the 21% of patients with a PRAD <43% and improved survival in the 10% with PRAD >65%. The association of the PRAD with survival benefit or harm was similar in patients with or without pre-GC ICD therapies. Conclusions Patients who received replacement of an ICD originally implanted for primary prevention and had at the time of GC either LVEF >35% alone or both LVEF ≤35% and PRAD <43% had worse survival versus controls without ICDs.

Long-term survival on LVAD support: Device complications and end-organ dysfunction limit long-term success.

BACKGROUND: Preoperative variables can predict short term left ventricular assist device (LVAD) survival, but predictors of extended survival remain insufficiently characterized. METHOD: Patients undergoing LVAD implant (2012-2018) in the Intermacs registry were grouped according to time on support: short-term (<1 year, n = 7,483), mid-term (MT, 1-3 years, n = 5,976) and long-term (LT, ≥3 years, n = 3,015). Landmarked hazard analyses (adjusted hazard ratio, HR) were performed to identify correlates of survival after 1 and 3 years of support. RESULTS: After surviving 1 year of support, additional LVAD survival was less likely in older (HR 1.15 per decade), Caucasian (HR 1.22) and unmarried (HR 1.16) patients (p < 0.05). After 3 years of support, only 3 preoperative characteristics (age, race, and history of bypass surgery, p < 0.05) correlated with extended survival. Postoperative events most negatively influenced achieving LT survival. In those alive at 1 year or 3 years, the occurrence of postoperative renal (creatinine HR MT = 1.09; LT HR = 1.10 per mg/dl) and hepatic dysfunction (AST HR MT = 1.29; LT HR = 1.34 per 100 IU), stroke (MT HR = 1.24; LT HR = 1.42), infection (MT HR = 1.13; LT HR = 1.10), and/or device malfunction (MT HR = 1.22; LT HR = 1.46) reduced extended survival (all p ≤ 0.03). CONCLUSIONS: Success with LVAD therapy hinges on achieving long term survival in more recipients. After 1 year, extended survival is heavily constrained by the occurrence of adverse events and postoperative end-organ dysfunction. The growth of destination therapy intent mandates that future LVAD studies be designed with follow up sufficient for capturing outcomes beyond 24 months.

Accuracy of risk models used for public reporting of heart transplant center performance.

BACKGROUND: Heart transplant programs and regulatory entities require highly accurate performance metrics to support internal quality improvement activities and national oversight of transplant programs, respectively. We assessed the accuracy of publicly reported performance measures. METHODS: We used the United Network for Organ Sharing registry to study patients who underwent heart transplantation between January 1, 2016 and June 30, 2018. We used tests of calibration to compare the observed rate of 1-year graft failure to the expected risk of 1-year graft failure, which was calculated for each recipient using the July 2019 method published by the Scientific Registry of Transplant Recipients (SRTR). The primary study outcome was the joint test of calibration, which accounts for both the total number of events predicted (calibration-in-the-large) and dispersion of risk predictions (calibration slope). RESULTS: 6,528 heart transplants were analyzed. The primary test of calibration failed (p <0.0001), indicating poor accuracy of the SRTR model. The calibration-in-the-large statistic (0.63, 95% confidence interval [CI] 0.58-0.68, p < 0.0001) demonstrated overestimation of event rates while the calibration slope statistic (0.56, 95% CI 0.49-0.62, p <0.0001) indicated over-dispersion of event rates. Pre-specified subgroup analyses demonstrated poor calibration for all subgroups (each p <0.01). After recalibration, program-level observed/expected ratios increased by a median of 0.14 (p <0.0001). CONCLUSIONS: Risk models employed for publicly-reported graft survival at U.S. heart transplant centers lack accuracy in general and in all subgroups tested. The use of disease-specific models may improve the accuracy of program performance metrics.

Long-term adult congenital heart disease survival after heart transplantation: A restricted mean survival time analysis.

BACKGROUND: Adult Congenital Heart Disease (ACHD) heart transplant recipients may have lower post-transplant survival resulting from higher peri-operative mortality than non-ACHD patients. However, the late risk of mortality appears lower in ACHD recipients. This study seeks to establish whether long-term heart transplant survival is reduced among ACHD recipients relative to non-ACHD recipients. METHODS: Adult patients who received a heart transplant between January, 2000 and December, 2019 in the United Network for Organ Sharing database were stratified by the presence of ACHD. Propensity-matched cohorts (1:4) were created to adjust for differences between groups. Graft survival at time points from 1 to 18 years was compared between groups using restricted mean survival time (RMST) analysis. RESULTS: The matched cohort included 1,139 ACHD and 4,293 non-ACHD patients. Median age was 35 years and 61% were male. Average survival time at 1 year was 0.85 years for ACHD patients and 0.93 years for non-ACHD patients (average difference: -0.08 years, 95% Confidence Interval [CI] -0.10 to -0.06, p < 0.001), reflecting higher immediate post-transplant mortality. Average survival time at 18 years was not clinically or statistically different: 11.14 years for ACHD patients and 11.40 years for non-ACHD patients (average difference: -0.26 years, 95% CI: -0.85 to + 0.32 years, p = 0.38). CONCLUSIONS: Despite increased medium-term mortality among ACHD patients after heart transplant, differences in long-term survival are minimal. Allocation of hearts to ACHD patients results in acceptable utility of donor hearts.

Post-Heart Transplant Care Pathway's Impact on Reducing Length of Stay.

BACKGROUND: Prolonged length of stay (LOS) has undesirable consequences including increased cost, resource consumption, morbidity, and disruptions in hospital flow. LOCAL PROBLEM: A high-volume heart transplant center in the Pacific Northwest had a mean index hospital LOS of 23 days, with a goal of 10 days according to the institutional heart transplant care pathway. METHODS: A retrospective, regression analysis was used to identify the factors contributing to LOS of 41 post-heart transplant patients. INTERVENTIONS: The post-heart transplant care pathway and order set were modified accordingly and reintroduced to the health care team. RESULTS: Factors contributing to LOS included number of days (1) until the first therapeutic calcineurin inhibitor level, (2) until intravenous diuretics were no longer required, and (3) outside of a therapeutic calcineurin inhibitor range. The interventions reduced the mean LOS by 8 days. CONCLUSIONS: Increased awareness of LOS, education, and consistent use of care pathways can significantly reduce length of stay.

Accuracy of Doppler blood pressure measurement in HeartMate 3 ventricular assist device patients.

AIMS: Optimal blood pressure (BP) control is imperative to reduce complications, especially strokes, in continuous flow ventricular assist device (VAD) patients. Doppler BP has been shown to be an accurate and reliable non-invasive BP measurement method in HeartMate II and HVAD patients. We examined whether Doppler BP is also accurate in patients with the HeartMate 3 VAD. METHODS AND RESULTS: In a prospective, longitudinal cohort of HeartMate 3 patients, arterial line BP and simultaneously measured Doppler opening pressure were obtained. Correlation and agreement between Doppler opening pressure and arterial line mean arterial pressure (MAP) versus systolic blood pressure (SBP) were analysed, as well as the effect of pulse pressure on the accuracy of Doppler opening pressure. A total of 589 pairs of simultaneous Doppler opening pressure and arterial line pressure readings were obtained in 43 patients. Doppler opening pressure had good correlation with intra-arterial MAP (r = 0.754) and more closely approximated MAP than SBP (mean error 2.0 vs. -8.6 mmHg). Pulse pressure did not have a clinically significant impact on the accuracy of the Doppler BP method. These results in HeartMate 3 patients are very similar to previous results in HeartMate II and HVAD patients. CONCLUSIONS: Doppler BP method should be the default non-invasive BP measurement method in continuous flow VAD patients including patients implanted with the HeartMate 3.

Patterns of Hospital Bypass and Interhospital Transfer Among Patients With Heart Failure.

BACKGROUND: We describe how patient characteristics influence hospital bypass, interhospital transfer, and in-hospital mortality in patients with heart failure in Washington. Rural patients with heart failure may bypass their nearest hospital or be transferred for appropriate therapies. The frequency, determinants, and outcomes of these practices remain uncharacterized. METHODS AND RESULTS: Mean excess travel times based on hospital and patient residence ZIP codes were calculated using published methods. Hospitals and servicing areas were coded based on bed size and ZIP code, respectively. Transfer patterns were analyzed using bootstrap inference for clusters. Analysis of mortality and transfer-associated factors was performed using logistic regression with generalized estimating equations. There were 48,163 patients, representing 1106 instances of transfer, studied. The mean excess travel time increased 7.14 minutes per decrease in population density (metropolitan, micropolitan, small town, rural; P < .0001). The rural mean excess travel time was greatest at 28.56 minutes. Transfer likelihood increased with younger age, male gender, admitting hospital rurality, higher Charlson Comorbidity Index, and stroke. Transfer was less likely among women (odds ratio [OR], 0.82; 95% confidence interval [CI], 0.72-0.94) and patients over 70 years old (OR, 0.15-0.46; 95% CI, 0.10-0.65). Adjusting for comorbidities and transfer propensity, transfer exhibited a stronger association with mortality than any other measured patient risk factor (OR, 2.15; 95% CI, 1.69-2.73), excluding stroke (OR, 7.09; 95% CI, 4.99-10.06). CONCLUSIONS: Rural hospital bypass is prevalent among patients with heart failure, although its clinical significance is unclear. Female and older patients were found to have a lesser likelihood of transfer adjusted for other factors. Interhospital transfer is associated with increased mortality when adjusted for comorbidities.

Deep phenotyping of cardiac function in heart transplant patients using cardiovascular system models.

KEY POINTS: Right heart catheterization data from clinical records of heart transplant patients are used to identify patient-specific models of the cardiovascular system. These patient-specific cardiovascular models represent a snapshot of cardiovascular function at a given post-transplant recovery time point. This approach is used to describe cardiac function in 10 heart transplant patients, five of which had multiple right heart catheterizations allowing an assessment of cardiac function over time. These patient-specific models are used to predict cardiovascular function in the form of right and left ventricular pressure-volume loops and ventricular power, an important metric in the clinical assessment of cardiac function. Outcomes for the longitudinally tracked patients show that our approach was able to identify the one patient from the group of five that exhibited post-transplant cardiovascular complications. ABSTRACT: Heart transplant patients are followed with periodic right heart catheterizations (RHCs) to identify post-transplant complications and guide treatment. Post-transplant positive outcomes are associated with a steady reduction of right ventricular and pulmonary arterial pressures, toward normal levels of right-side pressure (about 20 mmHg) measured by RHC. This study shows that more information about patient progression is obtained by combining standard RHC measures with mechanistic computational cardiovascular system models. The purpose of this study is twofold: to understand how cardiovascular system models can be used to represent a patient's cardiovascular state, and to use these models to track post-transplant recovery and outcome. To obtain reliable parameter estimates comparable within and across datasets, we use sensitivity analysis, parameter subset selection, and optimization to determine patient-specific mechanistic parameters that can be reliably extracted from the RHC data. Patient-specific models are identified for 10 patients from their first post-transplant RHC, and longitudinal analysis is carried out for five patients. Results of the sensitivity analysis and subset selection show that we can reliably estimate seven non-measurable quantities; namely, ventricular diastolic relaxation, systemic resistance, pulmonary venous elastance, pulmonary resistance, pulmonary arterial elastance, pulmonary valve resistance and systemic arterial elastance. Changes in parameters and predicted cardiovascular function post-transplant are used to evaluate the cardiovascular state during recovery of five patients. Of these five patients, only one showed inconsistent trends during recovery in ventricular pressure-volume relationships and power output. At the four-year post-transplant time point this patient exhibited biventricular failure along with graft dysfunction while the remaining four exhibited no cardiovascular complications.

Prediction of sudden cardiac death in Japanese heart failure patients: international validation of the Seattle Proportional Risk Model.

AIMS: Heart failure (HF) is associated with an increased risk of sudden cardiac death (SCD). This study sought to demonstrate the incidence of SCD within a multicentre Japanese registry of HF patients hospitalized for acute decompensation, and externally validate the Seattle Proportional Risk Model (SPRM). METHODS AND RESULTS: We consecutively registered 2240 acute HF patients from academic institutions in Tokyo, Japan. The discrimination and calibration of the SPRM were assessed by the c-statistic, Hosmer-Lemeshow statistic, and visual plotting among non-survivors. Patient-level SPRM predictions and implantable cardioverter-defibrillator (ICD) benefit [ICD estimated hazard ratio (HR), derived from the Cox proportional hazards model in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)] was calculated. During the 2-year follow-up, 356 deaths (15.9%) occurred, which included 76 adjudicated SCDs (3.4%) and 280 non-SCDs (12.5%). The SPRM showed acceptable discrimination [c-index = 0.63; 95% confidence interval (CI) 0.56-0.70], similar to that of original SPRM-derivation cohort. The calibration plot showed reasonable conformance. Among HF patients with reduced ejection fraction (EF; < 40%), SPRM showed improved discrimination compared with the ICD eligibility criteria (e.g. New York Heart Association functional Class II-III with EF ≤ 35%): c-index = 0.53 (95% CI 0.42-0.63) vs. 0.65 (95% CI 0.55-0.75) for SPRM. Finally, in the subgroup of 246 patients with both EF ≤ 35% and SPRM-predicted risk of ≥ 42.0% (SCD-HeFT defined ICD benefit threshold), mean ICD estimated HR was 0.70 (30% reduction of all-cause mortality by ICD). CONCLUSION: The cumulative incidence of SCD was 3.4% in Japanese HF registry. The SPRM performed reasonably well in Japanese patients and may aid in improving SCD prediction.

Modeling defibrillation benefit for survival among cardiac resynchronization therapy defibrillator recipients.

BACKGROUND: Patients with heart failure having a low expected probability of arrhythmic death may not benefit from implantable cardioverter defibrillators (ICDs). OBJECTIVE: The objective was to validate models to identify cardiac resynchronization therapy (CRT) candidates who may not require CRT devices with ICD functionality. METHODS: Heart failure (HF) patients with CRT-Ds and non-CRT ICDs from the National Cardiovascular Data Registry and others with no device from 3 separate registries and 3 heart failure trials were analyzed using multivariable Cox proportional hazards regression for survival with the Seattle Heart Failure Model (SHFM; estimates overall mortality) and the Seattle Proportional Risk Model (SPRM; estimates proportional risk of arrhythmic death). RESULTS: Among 60,185 patients (age 68.6 ±â€¯11.3 years, 31.9% female) meeting CRT-D criteria, 38,348 had CRT-Ds, 11,389 had non-CRT ICDs, and 10,448 had no device. CRT-D patients had a prominent adjusted survival benefit (HR 0.52, 95% CI 0.50-0.55, P < .0001 versus no device). CRT-D patients with SHFM-predicted 4-year survival ≥81% (median) and a low SPRM-predicted probability of an arrhythmic mode of death ≤42% (median) had an absolute adjusted risk reduction attributable to ICD functionality of just 0.95%/year with the majority of survival benefit (70%) attributable to CRT pacing. In contrast, CRT-D patients with SHFM-predicted survival median had substantially more ICD-attributable benefit (absolute risk reduction of 2.6%/year combined; P < .0001). CONCLUSIONS: The SPRM and SHFM identified a quarter of real-world, primary prevention CRT-D patients with minimal benefit from ICD functionality. Further studies to evaluate CRT pacemakers in these low-risk CRT candidates are indicated.

Left Ventricular Assist Device Inflow Cannula Insertion Depth Influences Thrombosis Risk.

Left ventricular assist device (LVAD) use has continued to grow. Despite recent advances in technology, LVAD patients continue to suffer from devastating complications, including stroke and device thrombosis. Among several variables affecting thrombogenicity, we hypothesize that insertion depth of the inflow cannula into the left ventricle (LV) influences hemodynamics and thrombosis risk. Blood flow patterns were studied in a patient-derived computational model of the LV, mitral valve (MV), and LVAD inflow cannula using unsteady computational fluid dynamics (CFD). Hundreds of thousands of platelets were tracked individually, for two inflow cannula insertion depth configurations (12 mm-reduced and 27 mm-conventional) using platelet-level (Lagrangian) metrics to quantify thrombogenicity. Particularly in patients with small LV dimensions, the deeper inflow cannula insertion resulted in much higher platelet shear stress histories (SH), consistent with markedly abnormal intraventricular hemodynamics. A larger proportion of platelets in this deeper insertion configuration was found to linger in the domain for long residence times (RT) and also accumulated much higher SH. The reduced inflow depth configuration promoted LV washout and reduced platelet SH. The increase of both SH and RT in the LV demonstrates the impact of inflow cannula depth on platelet activation and increased stroke risk in these patients. Inflow cannula depth of insertion should be considered as an opportunity to optimize surgical planning of LVAD therapy.

Improved Outcomes of Heart Transplantation in Adults With Congenital Heart Disease Receiving Regionalized Care.

BACKGROUND: The number of adult congenital heart disease (CHD) patients undergoing heart transplantation is increasing rapidly. CHD patients have higher surgical risk at transplantation. High-volume adult CHD transplant centers may have better transplant outcomes. OBJECTIVES: This study aimed to evaluate the effect of center CHD transplant volume and expertise on transplant outcomes in CHD patients. METHODS: The authors studied heart transplantations in CHD patients age ≥18 years using the United Network of Organ Sharing (UNOS) database for the primary outcomes of waitlist mortality and post-transplant outcomes at 30 days and 1 year. Transplant centers were assessed by status as the highest CHD transplant volume center in a UNOS region versus all others, presence of Adult Congenital Heart Association accreditation, and adult versus pediatric hospital designation. RESULTS: Between January of 2000 and June of 2018, 1,746 adult CHD patients were listed for transplant; 1,006 (57.6%) of these underwent heart transplantation. After adjusting for age, sex, listing status, and inotrope requirement, waitlist mortality risk was lower at Adult Congenital Heart Association accredited centers (hazard ratio: 0.730; p = 0.020). Post-transplant 30-day mortality was lower at the highest volume CHD transplant center in each UNOS region (hazard ratio: 0.706; p = 0.014). CONCLUSIONS: Designated expertise in CHD care is associated with improved waitlist outcomes for CHD patients listed for transplantation. Post-transplant survival was improved at the highest volume regional center. These findings suggest a possible advantage of regionalization of CHD transplantation.

Developing and implementing a heart failure data mart for research and quality improvement.

OBJECTIVE: The purpose of this project was to build and formatively evaluate a near-real time heart failure (HF) data mart. Heart Failure (HF) is a leading cause of hospital readmissions. Increased efforts to use data meaningfully may enable healthcare organizations to better evaluate effectiveness of care pathways and quality improvements, and to prospectively identify risk among HF patients. METHODS AND PROCEDURES: We followed a modified version of the Systems Development Life Cycle: 1) Conceptualization, 2) Requirements Analysis, 3) Iterative Development, and 4) Application Release. This foundational work reflects the first of a two-phase project. Phase two (in process) involves the implementation and evaluation of predictive analytics for clinical decision support. RESULTS: We engaged stakeholders to build working definitions and established automated processes for creating an HF data mart containing actionable information for diverse audiences. As of December 2017, the data mart contains information from over 175,000 distinct patients and >100 variables from each of their nearly 300,000 visits. CONCLUSION: The HF data mart will be used to enhance care, assist in clinical decision-making, and improve overall quality of care. This model holds the potential to be scaled and generalized beyond the initial focus and setting.

Validation and Recalibration of Seattle Heart Failure Model in Japanese Acute Heart Failure Patients.

BACKGROUND: Precise risk stratification in heart failure (HF) patients enables clinicians to tailor the intensity of their management. The Seattle Heart Failure Model (SHFM), which uses conventional clinical variables for its prediction, is widely used. We aimed to externally validate SHFM in Japanese HF patients with a recent episode of acute decompensation requiring hospital admission. METHODS AND RESULTS: SHFM was applied to 2470 HF patients registered in the West Tokyo Heart Failure and National Cerebral And Cardiovascular Center Acute Decompensated Heart Failure databases from 2006 to 2016. Discrimination and calibration were assessed with the use of the c-statistic and calibration plots, respectively, in HF patients with reduced ejection fraction (HFrEF; <40%) and preserved ejection fraction (HFpEF; ≥40%). In a perfectly calibrated model, the slope and intercept would be 1.0 and 0.0, respectively. The method of intercept recalibration was used to update the model. The registered patients (mean age 74 ± 13 y) were predominantly men (62%). Overall, 572 patients (23.2%) died during a mean follow-up of 2.1 years. Among HFrEF patients, SHFM showed good discrimination (c-statistic = 0.75) but miscalibration, tending to overestimate 1-year survival (slope = 0.78; intercept = -0.22). Among HFpEF patients, SHFM showed modest discrimination (c-statistic = 0.69) and calibration, tending to underestimate 1-year survival (slope = 1.18; intercept = 0.16). Intercept recalibration (replacing the baseline survival function) successfully updated the model for HFrEF (slope = 1.03; intercept = -0.04) but not for HFpEF patients. CONCLUSIONS: In Japanese acute HF patients, SHFM showed adequate performance after recalibration among HFrEF patients. Using prediction models to tailor the care for HF patients may improve the allocation of medical resources.

Small Left Ventricular Size Is an Independent Risk Factor for Ventricular Assist Device Thrombosis.

The prevalence of ventricular assist device (VAD) therapy has continued to increase due to a stagnant donor supply and growing advanced heart failure (HF) population. We hypothesize that left ventricular (LV) size strongly influences biocompatibility and risk of thrombosis. Unsteady computational fluid dynamics (CFD) was used in conjunction with patient-derived computational modeling and virtual surgery with a standard, apically implanted inflow cannula. A dual-focus approach of evaluating thrombogenicity was employed: platelet-based metrics to characterize the platelet environment and flow-based metrics to investigate hemodynamics. Left ventricular end-diastolic dimensions (LVEDds) ranging from 4.5 to 6.5 cm were studied and ranked according to relative thrombogenic potential. Over 150,000 platelets were individually tracked in each LV model over 15 cardiac cycles. As LV size decreased, platelets experienced markedly increased shear stress histories (SHs), whereas platelet residence time (RT) in the LV increased with size. The complex interplay between increased SH and longer RT has profound implications on thrombogenicity, with a significantly higher proportion of platelets in small LVs having long RT times and being subjected to high SH, contributing to thrombus formation. Our data suggest that small LV size, rather than decreased VAD speed, is the primary pathologic mechanism responsible for the increased incidence of thrombosis observed in VAD patients with small LVs.