Publications

AIMS: Prior trials have demonstrated that intravascular imaging (IVI)-guided percutaneous coronary intervention (PCI) results in less frequent target lesion revascularization and major adverse cardiovascular events (MACEs) compared with standard angiographic guidance. The uptake and associated outcomes of IVI-guided PCI in contemporary clinical practice in the USA remain unclear. Accordingly, temporal trends and comparative outcomes of IVI-guided PCI relative to PCI with angiographic guidance alone were examined in a broad, unselected population of Medicare beneficiaries.

METHODS AND RESULTS: Retrospective cohort study of Medicare beneficiary data from 1 January 2013, through 31 December 2019 to evaluate temporal trends and comparative outcomes of IVI-guided PCI as compared with PCI with angiography guidance alone in both the inpatient and outpatient settings. The primary outcomes were 1 year mortality and MACE, defined as the composite of death, myocardial infarction (MI), repeat PCI, or coronary artery bypass graft surgery. Secondary outcomes were MI or repeat PCI at 1 year. Multivariable Cox regression was used to estimate the adjusted association between IVI guidance and outcomes. Falsification endpoints (hospitalized pneumonia and hip fracture) were used to assess for potential unmeasured confounding. The study population included 1 189 470 patients undergoing PCI (38.0% female, 89.8% White, 65.1% with MI). Overall, IVI was used in 10.5% of the PCIs, increasing from 9.5% in 2013% to 15.4% in 2019. Operator IVI use was variable, with the median operator use of IVI 3.92% (interquartile range 0.36%-12.82%). IVI use during PCI was associated with lower adjusted rates of 1 year mortality [adjusted hazard ratio (aHR) 0.96, 95% confidence interval (CI) 0.94-0.98], MI (aHR 0.97, 95% CI 0.95-0.99), repeat PCI (aHR 0.74, 95% CI 0.73-0.75), and MACE (aHR 0.85, 95% CI 0.84-0.86). There was no association with the falsification endpoint of hospitalized pneumonia (aHR 1.02, 95% CI 0.99-1.04) or hip fracture (aHR 1.02, 95% CI 0.94-1.10).

CONCLUSION: Among Medicare beneficiaries undergoing PCI, use of IVI has increased over the previous decade but remains relatively infrequent. IVI-guided PCI was associated with lower risk-adjusted mortality, acute MI, repeat PCI, and MACE.

BACKGROUND: Multiple interventions, including catheter-directed therapy (CDT), systemic thrombolysis (ST), surgical embolectomy (SE), and therapeutic anticoagulation (AC) have been used to treat intermediate to high-risk pulmonary embolism (PE), but the most effective and safest treatment remains unclear. Our study aimed to investigate the efficacy and safety outcomes of each intervention.

METHODS: We queried PubMed and EMBASE in January 2023 and performed a network meta-analysis of observational studies and randomized controlled trials (RCT), including high or intermediate-risk PE patients, and comparing AC, CDT, SE, and ST. The primary outcomes were in-hospital mortality and major bleeding. The secondary outcomes included long-term mortality (≥6 months), recurrent PE, minor bleeding, and intracranial hemorrhage.

RESULTS: We identified 11 RCTs and 42 observational studies involving 157,454 patients. CDT was associated with lower in-hospital mortality than ST (odds ratio [OR] [95% confidence interval (CI)]: 0.41 [0.31-0.55]), AC (OR [95% CI]: 0.33 [0.20-0.53]), and SE (OR [95% CI]: 0.61 [0.39-0.96]). Recurrent PE in CDT was lower than ST (OR [95% CI]: 0.66 [0.50-0.87]), AC (OR [95% CI]: 0.36 [0.20-0.66]), and trended lower than SE (OR [95% CI]: 0.71 [0.40-1.26]). Notably, ST had higher major bleeding risks than CDT (OR [95% CI]: 1.51 [1.19-1.91]) and AC (OR [95% CI]: 2.21 [1.53-3.19]). By rankogram analysis, CDT presented the highest p-score in in-hospital mortality, long-term mortality, and recurrent PE.

CONCLUSION: In this network meta-analysis of observational studies and RCTs involving patients with intermediate to high-risk PE, CDT was associated with improved mortality outcomes compared to other therapies, without significant additional bleeding risk.

BACKGROUND/AIMS: When the randomized clusters in a cluster randomized trial are selected based on characteristics that influence treatment effectiveness, results from the trial may not be directly applicable to the target population. We used data from two large nursing home-based pragmatic cluster randomized trials to compare nursing home and resident characteristics in randomized facilities to eligible non-randomized and ineligible facilities.

METHODS: We linked data from the high-dose influenza vaccine trial and the Music & Memory Pragmatic TRIal for Nursing Home Residents with ALzheimer's Disease (METRICaL) to nursing home assessments and Medicare fee-for-service claims. The target population for the high-dose trial comprised Medicare-certified nursing homes; the target population for the METRICaL trial comprised nursing homes in one of four US-based nursing home chains. We used standardized mean differences to compare facility and individual characteristics across the three groups and logistic regression to model the probability of nursing home trial participation.

RESULTS: In the high-dose trial, 4476 (29%) of the 15,502 nursing homes in the target population were eligible for the trial, of which 818 (18%) were randomized. Of the 1,361,122 residents, 91,179 (6.7%) were residents of randomized facilities, 463,703 (34.0%) of eligible non-randomized facilities, and 806,205 (59.3%) of ineligible facilities. In the METRICaL trial, 160 (59%) of the 270 nursing homes in the target population were eligible for the trial, of which 80 (50%) were randomized. Of the 20,262 residents, 973 (34.4%) were residents of randomized facilities, 7431 (36.7%) of eligible non-randomized facilities, and 5858 (28.9%) of ineligible facilities. In the high-dose trial, randomized facilities differed from eligible non-randomized and ineligible facilities by the number of beds (132.5 vs 145.9 and 91.9, respectively), for-profit status (91.8% vs 66.8% and 68.8%), belonging to a nursing home chain (85.8% vs 49.9% and 54.7%), and presence of a special care unit (19.8% vs 25.9% and 14.4%). In the METRICaL trial randomized facilities differed from eligible non-randomized and ineligible facilities by the number of beds (103.7 vs 110.5 and 67.0), resource-poor status (4.6% vs 10.0% and 18.8%), and presence of a special care unit (26.3% vs 33.8% and 10.9%). In both trials, the characteristics of residents in randomized facilities were similar across the three groups.

CONCLUSION: In both trials, facility-level characteristics of randomized nursing homes differed considerably from those of eligible non-randomized and ineligible facilities, while there was little difference in resident-level characteristics across the three groups. Investigators should assess the characteristics of clusters that participate in cluster randomized trials, not just the individuals within the clusters, when examining the applicability of trial results beyond participating clusters.

IMPORTANCE: During the COVID-19 pandemic, many US states issued or revised pandemic preparedness plans guiding allocation of critical care resources during crises. State plans vary in the factors used to triage patients and have faced criticism from advocacy groups due to the potential for discrimination.

OBJECTIVE: To analyze the role of comorbidities and long-term prognosis in state triage procedures.

DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used data gathered from parallel internet searches for state-endorsed pandemic preparedness plans for the 50 US states, District of Columbia, and Puerto Rico (hereafter referred to as states), which were conducted between November 25, 2021, and June 16, 2023. Plans available on June 16, 2023, that provided step-by-step instructions for triaging critically ill patients were categorized for use of comorbidities and prognostication.

MAIN OUTCOMES AND MEASURES: Prevalence and contents of lists of comorbidities and their stated function in triage and instructions to predict duration of postdischarge survival.

RESULTS: Overall, 32 state-promulgated pandemic preparedness plans included triage procedures specific enough to guide triage in clinical practice. Twenty of these (63%) included lists of comorbidities that excluded (11 of 20 [55%]) or deprioritized (8 of 20 [40%]) patients during triage; one state's list was formulated to resolve ties between patients with equal triage scores. Most states with triage procedures (21 of 32 [66%]) considered predicted survival beyond hospital discharge. These states proposed different prognostic time horizons; 15 of 21 (71%) were numeric (ranging from 6 months to 5 years after hospital discharge), with the remaining 6 (29%) using descriptive terms, such as long-term.

CONCLUSIONS AND RELEVANCE: In this cross-sectional study of state-promulgated critical care triage policies, most plans restricted access to scarce critical care resources for patients with listed comorbidities and/or for patients with less-than-average expected postdischarge survival. This analysis raises concerns about access to care during a public health crisis for populations with high burdens of chronic illness, such as individuals with disabilities and minoritized racial and ethnic groups.

IMPORTANCE: Recent studies have produced inconsistent findings regarding the outcomes of the percutaneous microaxial left ventricular assist device (LVAD) during acute myocardial infarction with cardiogenic shock (AMICS).

OBJECTIVE: To compare the percutaneous microaxial LVAD vs alternative treatments among patients presenting with AMICS using observational analyses of administrative data.

DESIGN, SETTING, AND PARTICIPANTS: This comparative effectiveness research study used Medicare fee-for-service claims of patients admitted with AMICS undergoing percutaneous coronary intervention from October 1, 2015, through December 31, 2019. Treatment strategies were compared using (1) inverse probability of treatment weighting to estimate the effect of different baseline treatments in the overall population; (2) instrumental variable analysis to determine the effectiveness of the percutaneous microaxial LVAD among patients whose treatment was influenced by cross-sectional institutional practice patterns; (3) an instrumented difference-in-differences analysis to determine the effectiveness of treatment among patients whose treatment was influenced by longitudinal changes in institutional practice patterns; and (4) a grace period approach to determine the effectiveness of initiating the percutaneous microaxial LVAD within 2 days of percutaneous coronary intervention. Analysis took place between March 2021 and December 2022.

INTERVENTIONS: Percutaneous microaxial LVAD vs alternative treatments (including medical therapy and intra-aortic balloon pump).

MAIN OUTCOMES AND MEASURES: Thirty-day all-cause mortality and readmissions.

RESULTS: Of 23 478 patients, 14 264 (60.8%) were male and the mean (SD) age was 73.9 (9.8) years. In the inverse probability of treatment weighting analysis and grace period approaches, treatment with percutaneous microaxial LVAD was associated with a higher risk-adjusted 30-day mortality (risk difference, 14.9%; 95% CI, 12.9%-17.0%). However, patients receiving the percutaneous microaxial LVAD had a higher frequency of factors associated with severe illness, suggesting possible confounding by measures of illness severity not available in the data. In the instrumental variable analysis, 30-day mortality was also higher with percutaneous microaxial LVAD, but patient and hospital characteristics differed across levels of the instrumental variable, suggesting possible confounding by unmeasured variables (risk difference, 13.5%; 95% CI, 3.9%-23.2%). In the instrumented difference-in-differences analysis, the association between the percutaneous microaxial LVAD and mortality was imprecise, and differences in trends in characteristics between hospitals with different percutaneous microaxial LVAD use suggested potential assumption violations.

CONCLUSIONS: In observational analyses comparing the percutaneous microaxial LVAD to alternative treatments among patients with AMICS, the percutaneous microaxial LVAD was associated with worse outcomes in some analyses, while in other analyses, the association was too imprecise to draw meaningful conclusions. However, the distribution of patient and institutional characteristics between treatment groups or groups defined by institutional differences in treatment use, including changes in use over time, combined with clinical knowledge of illness severity factors not captured in the data, suggested violations of key assumptions that are needed for valid causal inference with different observational analyses. Randomized clinical trials of mechanical support devices will allow valid comparisons across candidate treatment strategies and help resolve ongoing controversies.

BACKGROUND: Leadless pacemakers (LPs) may mitigate the risk of lead failure and pocket infection related to conventional transvenous pacemakers. Atrial LPs are currently being investigated. However, the optimal and safest implant site is not known.

OBJECTIVES: We aimed to evaluate the right atrial (RA) anatomy and the adjacent structures using complementary analytic models [gross anatomy, cardiac magnetic resonance imaging (MRI), and computer simulation], to identify the optimal safest location to implant an atrial LP human.

METHODS AND RESULTS: Wall thickness and anatomic relationships of the RA were studied in 45 formalin-preserved human hearts. In vivo RA anatomy was assessed in 100 cardiac MRI scans. Finally, 3D collision modelling was undertaken assessing for mechanical device interaction. Three potential locations for an atrial LP were identified; the right atrial appendage (RAA) base, apex, and RA lateral wall. The RAA base had a wall thickness of 2.7 ± 1.6 mm, with a low incidence of collision in virtual implants. The anteromedial recess of the RAA apex had a wall thickness of only 1.3 ± 0.4 mm and minimal interaction in the collision modelling. The RA lateral wall thickness was 2.6 ± 0.9 mm but is in close proximity to the phrenic nerve and sinoatrial artery.

CONCLUSIONS: Based on anatomical review and 3D modelling, the best compromise for an atrial LP implantation may be the RAA base (low incidence of collision, relatively thick myocardial tissue, and without proximity to relevant epicardial structures); the anteromedial recess of the RAA apex and lateral wall are alternate sites. The mid-RAA, RA/superior vena cava junction, and septum appear to be sub-optimal fixation locations.