A Systematic Approach to the Evaluation of the Coronary Microcirculation Using Bolus Thermodilution: CATH CMD.

Coronary microvascular dysfunction (CMD) can cause myocardial ischemia in patients presenting with angina without obstructive coronary artery disease (ANOCA). Evaluating for CMD by using the thermodilution technique offers a widely accessible means of assessing microvascular resistance. Through this technique, 2 validated indices, namely coronary flow reserve and the index of microcirculatory resistance, can be computed, facilitating investigation of the coronary microcirculation. The index of microcirculatory resistance specifically estimates minimum achievable microvascular resistance within the coronary microcirculation. We aim to review the bolus thermodilution method, outlining the fundamental steps for conducting measurements and introducing an algorithmic approach (CATH CMD) to systematically evaluate the coronary microcirculation. Embracing a standardized approach, exemplified by the CATH CMD algorithm, will facilitate adoption of this technique and streamline the diagnosis of CMD.

Robotic unroofing of myocardial bridge of the left anterior descending coronary artery in a patient with hypertrophic obstructive cardiomyopathy and previous septal myectomy.

A 56-year-old female diagnosed with hypertrophic obstructive cardiomyopathy and myocardial bridge (MB) of the left anterior descending (LAD) coronary artery underwent septal myectomy with resolution of her left ventricular outflow tract gradient. She had ongoing refractory symptoms of exertional angina and fatigue for over a decade and finally presented to our clinic to be re-evaluated for treatment. Provocative angiographic testing confirmed significant ischemia secondary to LAD MB. She underwent robotic totally endoscopic off pump unroofing of the LAD MB with complete relief of her symptoms and return to full activity. We conclude that patients undergoing septal myectomy for hypertrophic obstructive cardiomyopathy should be evaluated for MB and undergo unroofing of the bridge at the time of surgery. Learning objective: A myocardial bridge (MB) is a condition in which a coronary artery, most often the left anterior descending, takes an intramuscular route and is covered by the myocardium leading to compression and potential ischemia. This case report adds to the growing body of evidence supporting the significance of considering MB in the overall management of hypertrophic obstructive cardiomyopathy, and the symptomatic relief that a patient can obtain from an unroofing procedure.

Heterogeneity promotes resilience in restored prairie: Implications for the environmental heterogeneity hypothesis.

Enhancing resilience in formerly degraded ecosystems is an important goal of restoration ecology. However, evidence for the recovery of resilience and its underlying mechanisms require long-term experiments and comparison with reference ecosystems. We used data from an experimental prairie restoration that featured long-term soil heterogeneity manipulations and data from two long-term experiments located in a comparable remnant (reference) prairie to (1) quantify the recovery of ecosystem functioning (i.e., productivity) relative to remnant prairie, (2) compare the resilience of restored and remnant prairies to a natural drought, and (3) test whether soil heterogeneity enhances resilience of restored prairie. We compared sensitivity and legacy effects between prairie types (remnant and restored) and among four prairie sites that included two remnant prairie sites and prairie restored under homogeneous and heterogeneous soil conditions. We measured sensitivity and resilience as the proportional change in aboveground net primary productivity (ANPP) during and following drought (sensitivity and legacy effects, respectively) relative to average ANPP based on 4 pre-drought years (2014-2017). In nondrought years, total ANPP was similar between remnant and restored prairie, but remnant prairie had higher grass productivity and lower forb productivity compared with restored prairie. These ANPP patterns generally persisted during drought. The sensitivity of total ANPP to drought was similar between restored and remnant prairie, but grasses in the restored prairie were more sensitive to drought. Post-drought legacy effects were more positive in the restored prairie, and we attributed this to the more positive and less variable legacy response of forb ANPP in the restored prairie, especially in the heterogeneous soil treatment. Our results suggest that productivity recovers in restored prairie and exhibits similar sensitivity to drought as in remnant prairie. Furthermore, creating heterogeneity promotes forb productivity and enhances restored prairie resilience to drought.

Angiographic Coronary Slow Flow Is Not a Valid Surrogate for Invasively Diagnosed Coronary Microvascular Dysfunction.

BACKGROUND: Ischemia with no obstructive coronary arteries is frequently caused by coronary microvascular dysfunction (CMD). Consensus diagnostic criteria for CMD include baseline angiographic slow flow by corrected TIMI (Thrombolysis In Myocardial Infarction) frame count (cTFC), but correlations between slow flow and CMD measured by invasive coronary function testing (CFT) are uncertain. OBJECTIVES: The aim of this study was to investigate relationships between cTFC and invasive CFT for CMD. METHODS: Adults with ischemia with no obstructive coronary arteries underwent invasive CFT with thermodilution-derived baseline coronary blood flow, coronary flow reserve (CFR), and index of microcirculatory resistance (IMR). CMD was defined as abnormal CFR (<2.5) and/or abnormal IMR (≥25). cTFC was measured from baseline angiography; slow flow was defined as cTFC >25. Correlations between cTFC and baseline coronary flow and between CFR and IMR and associations between slow flow and invasive measures of CMD were evaluated, adjusted for covariates. All patients provided consent. RESULTS: Among 508 adults, 49% had coronary slow flow. Patients with slow flow were more likely to have abnormal IMR (36% vs 26%; P = 0.019) but less likely to have abnormal CFR (28% vs 42%; P = 0.001), with no difference in CMD (46% vs 51%). cTFC was weakly correlated with baseline coronary blood flow (r = -0.35; 95% CI: -0.42 to -0.27), CFR (r = 0.20; 95% CI: 0.12 to 0.28), and IMR (r = 0.16; 95% CI: 0.07-0.24). In multivariable models, slow flow was associated with lower odds of abnormal CFR (adjusted OR: 0.53; 95% CI: 0.35 to 0.80). CONCLUSIONS: Coronary slow flow was weakly associated with results of invasive CFT and should not be used as a surrogate for the invasive diagnosis of CMD.

Cardiogenic Shock Intravascular Cooling Trial (CHILL-SHOCK).

BACKGROUND: Cardiogenic shock (CS) is complicated by high mortality rates. Targeted temperature control (TTC) has been proposed as an adjunct therapy in CS. This study aims to examine the safety of TTC in patients presenting with CS. METHODS AND RESULTS: In this open-label, randomized controlled pilot trial, 20 patients with hemodynamic criteria for CS were assigned to standard of care plus TTC vs standard of care alone. The primary outcome was a composite safety outcome, including well-described complications of TTC. Secondary outcomes included mortality at 90 days, invasive hemodynamic and echocardiographic parameters, electrocardiographic measurements, and inotrope dosing. There were no significant differences in the composite analysis of prespecified safety outcomes (3 events in the TTC group vs 0 events in the control group; P = 0.24). Patients randomized to TTC demonstrated a statistically significant increase in cardiac index and cardiac power index compared to the control group at 48-96 hours after randomization (3.6 [3.1, 3.9] L/min/m2 vs 2.6 [2.5, 3.15] L/min/m2; P = 0.029 and 0.61 [0.55, 0.7] W/m2 vs 0.53 [0.435, 0.565] W/m2; P = 0.029, respectively). CONCLUSION: TTC may be a safe adjunct therapy for patients presenting with CS and may yield improvement in specific hemodynamic parameters.

An exploration of the experiences and self-generated strategies used when navigating everyday life with Long Covid.

BACKGROUND: Around one in ten people who contract Covid-19 report ongoing symptoms or 'Long Covid'. Without any known interventions to cure the condition, forms of self-management are routinely prescribed by healthcare professionals and described by people with the condition. However, there is limited research exploring what strategies are used to navigate everyday life with Long Covid, and experiences that initiate development of these strategies. Our study aimed to explore the range and influence of self-generated strategies used by people with Long Covid to navigate everyday life within the context of their own condition. METHODS: Forming part of the Long Covid Personalised Self-managemenT support co-design and EvaluatioN (LISTEN) project, we conducted a qualitative study using narrative interviews with adults who were not hospitalised with Covid-19. Participants aged over 18 years, who self-identified with Long Covid, were recruited from England and Wales. Data were analysed with patient contributors using a reflexive thematic analysis. RESULTS: Eighteen participants (mean age = 44 years, SD = 13 years) took part in interviews held between December 2021 and February 2022. Themes were constructed which depicted 1) the landscape behind the Long Covid experience and 2) the everyday experience of participants' Long Covid. The everyday experience comprised a combination of physical, emotional, and social factors, forming three sub-themes: centrality of physical symptoms, navigating 'experts' and the 'true colour' of personal communities, and a rollercoaster of psychological ambiguity). The third theme, personal strategies to manage everyday life was constructed from participants' unique presentations and self-generated solutions to manage everyday life. This comprised five sub-themes: seeking reassurance and knowledge, developing greater self-awareness through monitoring, trial and error of 'safe' ideas, building in pleasure and comfort, and prioritising 'me'. CONCLUSIONS: Among this sample of adults with Long Covid, their experiences highlighted the unpredictable nature of the condition but also the use of creative and wide ranging self-generated strategies. The results offer people with Long Covid, and healthcare professionals supporting them, an overview of the collective evidence relating to individuals' self-management which can enable ways to live 'better' and regain some sense of identity whilst facing the impact of a debilitating, episodic condition. TRIAL REGISTRATION: LISTEN ISRCTN36407216.

Comprehensive Management of ANOCA, Part 1-Definition, Patient Population, and Diagnosis: JACC State-of-the-Art Review.

Angina with nonobstructive coronary arteries (ANOCA) is increasingly recognized and may affect nearly one-half of patients undergoing invasive coronary angiography for suspected ischemic heart disease. This working diagnosis encompasses coronary microvascular dysfunction, microvascular and epicardial spasm, myocardial bridging, and other occult coronary abnormalities. Patients with ANOCA often face a high burden of symptoms and may experience repeated presentations to multiple medical providers before receiving a diagnosis. Given the challenges of establishing a diagnosis, patients with ANOCA frequently experience invalidation and recidivism, possibly leading to anxiety and depression. Advances in scientific knowledge and diagnostic testing now allow for routine evaluation of ANOCA noninvasively and in the cardiac catheterization laboratory with coronary function testing (CFT). CFT includes diagnostic coronary angiography, assessment of coronary flow reserve and microcirculatory resistance, provocative testing for endothelial dysfunction and coronary vasospasm, and intravascular imaging for identification of myocardial bridging, with hemodynamic assessment as needed.

Comprehensive Management of ANOCA, Part 2-Program Development, Treatment, and Research Initiatives: JACC State-of-the-Art Review.

Centers specializing in coronary function testing are critical to ensure a systematic approach to the diagnosis and treatment of angina with nonobstructive coronary arteries (ANOCA). Management leveraging lifestyle, pharmacology, and device-based therapeutic options for ANOCA can improve angina burden and quality of life in affected patients. Multidisciplinary care teams that can tailor and titrate therapies based on individual patient needs are critical to the success of comprehensive programs. As coronary function testing for ANOCA is more widely adopted, collaborative research initiatives will be fundamental to improve ANOCA care. These efforts will require standardized symptom assessments and data collection, which will propel future large-scale clinical trials.

Multimodal single-cell datasets characterize antigen-specific CD8+ T cells across SARS-CoV-2 vaccination and infection.

The immune response to SARS-CoV-2 antigen after infection or vaccination is defined by the durable production of antibodies and T cells. Population-based monitoring typically focuses on antibody titer, but there is a need for improved characterization and quantification of T cell responses. Here, we used multimodal sequencing technologies to perform a longitudinal analysis of circulating human leukocytes collected before and after immunization with the mRNA vaccine BNT162b2. Our data indicated distinct subpopulations of CD8+ T cells, which reliably appeared 28 days after prime vaccination. Using a suite of cross-modality integration tools, we defined their transcriptome, accessible chromatin landscape and immunophenotype, and we identified unique biomarkers within each modality. We further showed that this vaccine-induced population was SARS-CoV-2 antigen-specific and capable of rapid clonal expansion. Moreover, we identified these CD8+ T cell populations in scRNA-seq datasets from COVID-19 patients and found that their relative frequency and differentiation outcomes were predictive of subsequent clinical outcomes.

Use of Intravascular Ultrasound and Coronary Angiography to Measure the Prevalence of Myocardial Bridge in Heart Transplant Patients.

Myocardial bridge (MB) detection rates vary across methods and most studies that have assessed MB include symptomatic patients. Intravascular ultrasound (IVUS) is a sensitive tool for MB detection and donor hearts may serve as a surrogate measure of asymptomatic patients. We used IVUS and coronary angiography to measure MB prevalence in heart transplant patients during routine follow-up invasive coronary assessments. This was a retrospective, single-center study of heart transplant patients who received follow-up coronary assessments at the University of Chicago Heart and Vascular Center between December 2014 and December 2021. A single experienced interventional cardiologist assessed incidental findings of MB in IVUS and coronary angiography. Detection rates were compared with meta-analysis-reported prevalence. Of 129 patients, IVUS-detected MB in 87 patients (67.4%), whereas coronary angiography detected 41 (31.8%). All MB found by coronary angiography were detected by IVUS. Some level of cardiac allograft vasculopathy was found in 92 patients (71.3%). Our IVUS-detected MB prevalence was greater than meta-analysis-reported pooled prevalence across all methods: autopsy, computed tomography angiography, and coronary angiography (67.4% [95% confidence interval [CI] 59.4 to 75.5] vs 42% [95% CI 30 to 55]; 22% [95% CI 18 to 25]; 6% [95% CI 5 to 8], p ≤0.005). The difference between our observed IVUS-detected MB prevalence and meta-analysis autopsy reported MB prevalence was 1.25 (95% CI 1.11 to 1.40). In conclusion, the high prevalence of MB recorded in donor hearts emphasizes the need to further investigate the causes of chest pain in patients who are found to have MB.

Sternal-Sparing Surgical Options in Combined Aortic Valve and Coronary Artery Disease: Proof of Concept.

OBJECTIVE: The standard management of concomitant aortic valve (AV) and coronary artery disease has been coronary artery bypass and AV replacement (AVR). With the advent of minimally invasive options, many isolated lesions have been successfully managed using a sternal-sparing approach. In our institution, patients with isolated AV disease are offered minimally invasive surgical or transcatheter AVR, and those with isolated coronary artery disease are routinely managed with robotic totally endoscopic coronary artery bypass or percutaneous coronary intervention. Various combinations of these techniques can be used when a sternal-sparing posture is desired because of patient risk or preference. The aim of this study was to review the outcomes in patients with combined AV and coronary disease who were managed using sternal-sparing approaches. METHODS: We reviewed the records of 10 patients in our minimally invasive surgical database who presented with concomitant AV and coronary artery disease and underwent combined sternal-sparing management of these 2 lesions using various combinations of minimally invasive approaches. RESULTS: Four patients had totally endoscopic coronary artery bypass and minimally invasive AVR at the same time, 2 patients underwent transcatheter AVR followed by totally endoscopic coronary artery bypass, and 4 patients underwent minimally invasive AVR with percutaneous coronary intervention. There was no 30-day mortality. The duration of postoperative surgical hospital stay was 3.1 ± 0.9 days. CONCLUSIONS: Sternal-sparing approaches in combined AV and coronary artery disease are feasible with patient-specific treatment selection of minimally invasive techniques.

Phospho-seq: Integrated, multi-modal profiling of intracellular protein dynamics in single cells.

Cell signaling plays a critical role in regulating cellular behavior and fate. While multimodal single-cell sequencing technologies are rapidly advancing, scalable and flexible profiling of cell signaling states alongside other molecular modalities remains challenging. Here we present Phospho-seq, an integrated approach that aims to quantify phosphorylated intracellular and intranuclear proteins, and to connect their activity with cis-regulatory elements and transcriptional targets. We utilize a simplified benchtop antibody conjugation method to create large custom antibody panels for simultaneous protein and scATAC-seq profiling on whole cells, and integrate this information with scRNA-seq datasets via bridge integration. We apply our workflow to cell lines, induced pluripotent stem cells, and 3-month-old brain organoids to demonstrate its broad applicability. We demonstrate that Phospho-seq can define cellular states and trajectories, reconstruct gene regulatory relationships, and characterize the causes and consequences of heterogeneous cell signaling in neurodevelopment.

Exercise-Induced Left Atrial Hypertension in Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Many patients with heart failure and preserved ejection fraction have no overt volume overload and normal resting left atrial (LA) pressure. OBJECTIVES: This study sought to characterize patients with normal resting LA pressure (pulmonary capillary wedge pressure [PCWP] <15 mm Hg) but exercise-induced left atrial hypertension (EILAH). METHODS: The REDUCE LAP-HF II (A Study to Evaluate the Corvia Medical, Inc. IASD System II to Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) trial randomized 626 patients with ejection fraction ≥40% and exercise PCWP ≥25 mm Hg to atrial shunt or sham procedure. The primary trial outcome, a hierarchical composite of death, heart failure hospitalization, intensification of diuretics, and change in health status was compared between patients with EILAH and those with heart failure and resting left atrial hypertension (RELAH). RESULTS: Patients with EILAH (29%) had similar symptom severity, but lower natriuretic peptide levels, higher 6-minute walk distance, less atrial fibrillation, lower left ventricular mass, smaller LA volumes, lower E/e', and better LA strain. PCWP was lower at rest, but had a larger increase with exercise in EILAH. Neither group as a whole had a significant effect from shunt therapy vs sham. Patients with EILAH were more likely to have characteristics associated with atrial shunt responsiveness (peak exercise pulmonary vascular resistance <1.74 WU) and no pacemaker (63% vs 46%; P < 0.001). The win ratio for the primary outcome was 1.56 (P = 0.08) in patients with EILAH and 1.51 (P = 0.04) in those with RELAH when responder characteristics were present. CONCLUSIONS: Patients with EILAH had similar symptom severity but less advanced myocardial and pulmonary vascular disease. This important subgroup may be difficult to diagnose without invasive exercise hemodynamics, but it has characteristics associated with favorable response to atrial shunt therapy. (A Study to Evaluate the Corvia Medical, Inc. IASD System II to Reduce Elevated Left Atrial Pressure in Patients With Heart Failure [REDUCE LAP-HF TRIAL II]; NCT03088033).

Multimodal characterization of antigen-specific CD8 + T cells across SARS-CoV-2 vaccination and infection.

The human immune response to SARS-CoV-2 antigen after infection or vaccination is defined by the durable production of antibodies and T cells. Population-based monitoring typically focuses on antibody titer, but there is a need for improved characterization and quantification of T cell responses. Here, we utilize multimodal sequencing technologies to perform a longitudinal analysis of circulating human leukocytes collected before and after BNT162b2 immunization. Our data reveal distinct subpopulations of CD8 + T cells which reliably appear 28 days after prime vaccination (7 days post boost). Using a suite of cross-modality integration tools, we define their transcriptome, accessible chromatin landscape, and immunophenotype, and identify unique biomarkers within each modality. By leveraging DNA-oligo-tagged peptide-MHC multimers and T cell receptor sequencing, we demonstrate that this vaccine-induced population is SARS-CoV-2 antigen-specific and capable of rapid clonal expansion. Moreover, we also identify these CD8 + populations in scRNA-seq datasets from COVID-19 patients and find that their relative frequency and differentiation outcomes are predictive of subsequent clinical outcomes. Our work contributes to our understanding of T cell immunity, and highlights the potential for integrative and multimodal analysis to characterize rare cell populations.

Multiple global change drivers show independent, not interactive effects: a long-term case study in tallgrass prairie.

Ecosystems are faced with an onslaught of co-occurring global change drivers. While frequently studied independently, the effects of multiple global change drivers have the potential to be additive, antagonistic, or synergistic. Global warming, for example, may intensify the effects of more variable precipitation regimes with warmer temperatures increasing evapotranspiration and thereby amplifying the effect of already dry soils. Here, we present the long-term effects (11 years) of altered precipitation patterns (increased intra-annual variability in the growing season) and warming (1 °C year-round) on plant community composition and aboveground net primary productivity (ANPP), a key measure of ecosystem functioning in mesic tallgrass prairie. Based on past results, we expected that increased precipitation variability and warming would have additive effects on both community composition and ANPP. Increased precipitation variability altered plant community composition and increased richness, with no effect on ANPP. In contrast, warming decreased ANPP via reduction in grass stems and biomass but had no effect on the plant community. Contrary to expectations, across all measured variables, precipitation and warming treatments had no interactive effects. While treatment interactions did not occur, each treatment did individually impact a different component of the ecosystem (i.e., community vs. function). Thus, different aspects of the ecosystem may be sensitive to different global change drivers in mesic grassland ecosystems.

Long-Term Outcomes of Patients With Pulmonary Embolism Managed With Endovascular Therapies Compared to Medical Therapy.

Background: Guidelines on the management of acute pulmonary embolism (PE) recommend consideration of endovascular therapies (EVT) for patients at intermediate-high risk. However, long-term data on the outcomes of patients after EVT as compared to medical therapy is lacking. This study aimed to compare outcomes of patients receiving EVT as compared to medical therapy alone at 3 to 6 months. Methods: In this single-center, retrospective cohort study, 190 patients with PE underwent evaluation for presence of right ventricular (RV) dysfunction by transthoracic echocardiogram, residual perfusion defects on ventilation-perfusion scanning, and functional capacity by 6-minute walk distance (6MWD) at 3 to 6 month follow-up. Results: Fifty-eight (31%) patients received EVT for the management of their acute PE. At follow-up (median 120 [97-170] days), 71% of patients who received EVT had normalization of RV function compared with only 34% of patients who received medical therapy alone (P < .001). Patients who received EVT had a significantly greater increase in their estimated glomerular filtration rate (P = .001), decrease in N-terminal proB-type natriuretic peptide (P = .003), and decrease in hemoglobin values (P = .018). Patients with intermediate-high to high risk PE who received EVT had significantly greater distance achieved on their 6MWD as compared to those who received medical therapy alone (P = .025). Conclusions: Patients with acute PE who received EVT plus medical therapy were more likely to achieve normalization of RV dysfunction at 3 to 6 month follow-up compared to patients who received medical therapy alone. These data suggest that EVT is an effective therapy option for acute PE in intermediate-high and high risk patients with potential durable long-term benefits.

Cross-Site Comparisons of Dryland Ecosystem Response to Climate Change in the US Long-Term Ecological Research Network.

Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.

Reintroducing bison results in long-running and resilient increases in grassland diversity.

The widespread extirpation of megafauna may have destabilized ecosystems and altered biodiversity globally. Most megafauna extinctions occurred before the modern record, leaving it unclear how their loss impacts current biodiversity. We report the long-term effects of reintroducing plains bison (Bison bison) in a tallgrass prairie versus two land uses that commonly occur in many North American grasslands: 1) no grazing and 2) intensive growing-season grazing by domesticated cattle (Bos taurus). Compared to ungrazed areas, reintroducing bison increased native plant species richness by 103% at local scales (10 m2) and 86% at the catchment scale. Gains in richness continued for 29 y and were resilient to the most extreme drought in four decades. These gains are now among the largest recorded increases in species richness due to grazing in grasslands globally. Grazing by domestic cattle also increased native plant species richness, but by less than half as much as bison. This study indicates that some ecosystems maintain a latent potential for increased native plant species richness following the reintroduction of native herbivores, which was unmatched by domesticated grazers. Native-grazer gains in richness were resilient to an extreme drought, a pressure likely to become more common under future global environmental change.