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Abstract Background Patients with ischemia and nonobstructive coronary arteries (INOCA) suffer from a broad range of anginal symptoms that may differ depending on the biologic sex of the patient, the underlying coronary vasomotor disorder, or the type of presentation. Purpose We sought to characterize the symptom description and angina classification of patients referred for invasive coronary function testing (CFT) in the DISCOVER INOCA multicenter registry, stratified by type of presentation (stable vs unstable), biologic sex, and underlying diagnosis, including coronary microvascular dysfunction (CMD), vasospastic angina (VSA), or other disorders such as symptomatic myocardial bridging. Methods DISCOVER INOCA is a prospective, multicenter registry in the United States that includes patients who are referred for clinically indicated coronary angiography and found to have INOCA. All patients underwent protocol-guided angiography, acetylcholine provocation, coronary thermodilution, and intravascular imaging. Symptom characteristics were compared between groups. Results From September 2022 until February 2024, 104 patients were enrolled, 78% were female, and mean age was 57 ± 11 years. The post-procedure diagnosis was CMD in 19%, VSA in 41%, a mixed syndrome in 15%, or other diagnosis in 26%. The average coronary flow reserve (CFR) was 2.9 ± 1.1 in the CMD group and 5.3 ± 3.0 in the VSA group, (p < 0.001). 53% of patients presented with stable angina and 47% with unstable or progressive symptoms. Symptoms included chest pain (89%), chest tightness (42%), chest pressure (39%), shortness of breath (53%), and fatigue (16%), and no significant differences were reported when stratified by diagnostic phenotype. Female patients were more likely to report arm/neck/back/jaw pain (25% vs 5% in men, p = 0.038). Symptom triggers included exertion/activity in 73%, emotional stress in 12%, and resting symptoms in 58%. In female patients 4% reported catamenial symptoms. Of patients with stable angina, the Canadian Cardiovascular Society (CCS) Angina Classification was Grade I in 25%, Grade II in 52%, Grade III in 21%, and Grade IV in 2%. In patients with unstable angina, the Braunwald Angina Classification was Class I in 9%, Class II in 73%, and Class III in 18%. Conclusions Patients with INOCA referred for clinically indicated coronary angiography and CFT were predominantly female and most commonly reported chest pain as a presenting symptom. Female patients were more likely to report arm/neck/back/jaw pain than male patients. Over half of patients reported resting symptoms with no differences between the diagnostic phenotypes (CMD, VSA, or other). The CCS and Braunwald angina classification indicated that most patients had moderate intensity symptoms. Patient-reported outcome measures will be used to systematically categorize the symptom burden in these patients.

Abstract Background Six percent of patients presenting with acute myocardial infarction (MI) have MI with non-obstructed coronary artery disease (MINOCA). Coronary microvascular disease (CMD) is common in angina with non-obstructive coronary artery disease (ANOCA), but its prevalence and severity in MINOCA is undefined. Purpose Patients with CMD may have elevated risk of myocardial infarction despite no significant stenosis. We tested the hypothesis that patients with MINOCA have more significant burden of CMD than patients with ANOCA. Methods A retrospective case-control study was performed on patients who underwent invasive testing for signs of coronary ischemia and found to have non-obstructive disease (stenoses< 50%). Cases of MI were classified as MINOCA (n=87) and compared to patients with ANOCA (n=552). Patients with spontaneous coronary artery dissection, myocarditis, Takotsubo cardiomyopathy or prior atherothrombotic MI were excluded. Coronary catheterization was performed followed by invasive provocation testing with adenosine and acetylcholine using a Doppler flow wire. CMD was subdivided into endothelium-independent, defined as coronary flow reserve (CFR) < 2.5 with intra-coronary adenosine, and endothelium dependent, defined as < 50% increase in coronary blood flow with acetylcholine. Epicardial vasoconstriction > 90% with typical anginal symptoms was classified as epicardial vasospasm. Results There was no difference in age, sex or traditional coronary risk factors between the MINOCA and ANOCA groups (Table 1). Fifty (57%) of patients with MINOCA had type 2 MI secondary to supply-demand mismatch. Both MINOCA and suspected ANOCA patients had a high prevalence of CMD (71% vs 67%) and endothelium-independent CMD is more prevalent in MINOCA (64.5% vs 50.4%). Although odds of endothelium-dependent CMD were similar, the CFR within this group and CMD overall was worse in MINOCA patients (Figure 1). There was no difference in epicardial spasm. Conclusion Coronary microvascular disease and vasomotor dysfunction are common in patients with MINOCA, with a higher prevalence of endothelium-independent CMD and more severe CMD overall compared to patients with ANOCA. Treatment of CMD in patients with MINOCA may help reduce recurrence and warrants further investigation.

Abstract Background Vascular aging is a key feature of cardiovascular disease. α-klotho (klotho) is a protein inversely associated with aging and may contribute to vascular repair. Lower levels of systemic klotho have been identified in humans with features of early and advanced coronary atherosclerosis. It remains unknown if circulating klotho is present within human coronary circulation and whether cardiovascular klotho retention correlates with atherosclerosis. Purpose The current study aimed to assess the presence of klotho within coronary circulation compared to systemic circulation and hypothesized that net coronary klotho retention is attenuated in patients with early age-related features of coronary artery disease (CAD). Methods A total of 42 patients that underwent clinically indicated coronary angiogram for chest pain that had no obstructive CAD underwent intravascular ultrasound (IVUS) assessment were retrospectively examined. Virtual histology assessed coronary plaque characteristics. Blood samples simultaneously collected from the proximal aorta and coronary sinus were used for klotho detection using enzyme-linked immunosorbent assay. The net gradient of klotho across cardiovascular circulation was calculated by multiplying the arteriovenous klotho gradient by basal coronary blood flow. A net positive gradient indicated less cardiovascular klotho retention; a net negative gradient indicated greater cardiovascular klotho retention. Results Overall, participants were age 54±10 years old and 76% were female. There were overall higher levels of klotho within the coronary sinus (median 0.49 ng/mL [0.15; 1.69]) compared to systemic circulation (median 0.30 ng/mL [0.16; 1.14]). Participant groups were determined by those with positive (n = 20) or negative (n = 22) cardiovascular retention of klotho. Both groups were similar in age (56 ±2 vs. 51 ±2 years old, p = 0.080), gender (72% vs. 80% female, p = 0.580), and had similar occurrences of traditional cardiovascular comorbidities. Those with less cardiovascular klotho retention in the coronary vascular bed had significantly greater degree of non-obstructive coronary artery plaque (Gensini score 3.5 vs. 0, p < 0.001) and had higher percent plaque burden (46% [35; 53] vs. 34% [28; 46], p = 0.044) than those with greater cardiovascular klotho retention. Conclusions Patients with early coronary atherosclerosis may be characterized by attenuated retention of klotho within coronary circulation. Moreover, humans appear to have higher circulating klotho in coronary circulation than in systemic circulation. The current study may support a role for mechanism or potential therapeutic target for klotho in coronary atherosclerosis in humans.

Abstract Background/Introduction The use of a single low high-sensitivity cardiac troponin measurement to rule out myocardial infarction (MI) at presentation is advocated by international guidelines. Studies have not systematically compared high-sensitivity cardiac troponin (hs-cTn) I and T assays to determine which values should be used to rule out MI in patients with suspected acute coronary syndrome. Methods In a pooled analysis from three prospective observational cohort studies the lowest cTn concentration was determined that gave a negative predictive value (NPV) of ≥99.5% for MI or death at 30 days on presentation to the emergency department. EDTA or lithium heparin plasma or serum samples collected at presentation were measured using five hs-cTnI assays (Abbott ARCHITECT i2000, Beckman Coulter Access 2, Siemens Atellica IM, Ortho-Clinical Diagnostics VITROS 5600, LSI Medience PATHFAST) and one hs-cTnT assay (Roche Cobas e411). The diagnostic outcome of MI or death at 30 days was adjudicated according to the Fourth Universal Definition of MI. Optimal thresholds were determined to identify the highest proportion of patients that could be considered for discharge for a NPV of ≥99.5% for each assay. Results Among 941 patients, MI or death at 30 days occurred in 113 (12%). Optimized thresholds varied between assays ranging from <2 to <7 ng/L (Table) that identified between 22% and 60% of patients as low risk (0-1%) for MI or death at 30 days. Conclusions Our data identify differences in the effectiveness of thresholds between hs-cTnI and hs-cTnT assays for the same safety performance to rule out MI on presentation using a single measurement. In some cases, these thresholds differ from those used in clinical practice. Due to lack of assay standardization, optimal decision thresholds should be defined and validated for each high sensitivity cTn assay.

Abstract Background Diagnosing myocardial infarction (MI) in patients with chronic kidney disease (CKD) is difficult as these patients often have elevated baseline high-sensitivity cardiac troponin T (hs-cTnT) concentrations. Methods Observational U.S. cohort study of emergency department (ED) patients undergoing hs-cTnT measurement. Cases with >1 hs-cTnT increase >99th percentile were adjudicated following the Fourth Universal Definition of MI. Diagnostic performance of baseline and serial 2- and 6-hour hs-cTnT thresholds for ruling-in acute MI was compared between those without and with CKD (eGFR <60 ml/min/1.73m2). Results The study cohort included 1992 patients, amongst whom 501 (25%) had CKD. There were 701 (82%) patients with myocardial injury, 64 (7.5%) with type 1, and 91 (11%) with type 2 MI. In CKD patients with baseline hs-cTnT thresholds of >52, >100, >200 or >300 ng/L, PPVs for acute MI were 37% [95% CI 28-46], 53% (95% CI 39-67), 73% (95% CI 50-89) and 80% (95% CI 44-98), and in those without CKD, 64% (95% CI 50-77), 69% (95% CI 49-85), 59% (95% CI 33-82) and 54% (95% CI 25-81). In CKD patients with a 2-hour hs-cTnT delta of >10, >20 or >30 ng/L, the corresponding PPVs were 65% (95% CI 50-78), 86% (95% CI 68-96) and 88% (95% CI 68-97), and in those without CKD, 65% (95% CI 51-78), 73% (95% CI 57-86) and 75% (95% CI 58-88) (Figure). Conclusion Diagnostic performance of standard baseline and serial 2-hour hs-cTnT thresholds to rule-in MI is suboptimal in patients with CKD. It significantly improves when using higher baseline thresholds and delta values.

Abstract Background Heart failure (HF) with abnormal left ventricular (LV) ejection fraction (EF) manifests in multiple phenotypes, each presenting distinct and potentially actionable therapeutic targets. This study aimed to assess the potential of the ABCDE+ stress echocardiography (SE) protocol in uncovering different phenotypes of non-ischemic HF. Methods With a retrospective analysis of prospectively acquired data, we identified 265 patients (mean age: 65.7±12.6 years; 154 males, 59.9%) with non-ischemic HF with EF<50% (mean =41.4±7.5) enrolled by 23 certified laboratories between 2021 and 2023. Ischemic origin was excluded based on data of angiography and medical history. ABCDE-SE was evaluated with exercise (n=98, 37.0%), dobutamine (n=50, 18.9%), or vasodilators (n=117, 44.1%). The protocol consisted of several steps: A assessed regional wall motion abnormality (RWMA); B evaluated number of B-lines; C measured left ventricular contractile reserve; Step D with coronary flow velocity reserve (CFVR) in the left anterior descending artery (LAD) was completed in 102 patients (38.5%); step E assessed heart rate reserve. Additionally, step F (evaluated in 188 patients at rest and 107 at peak stress) noted the presence of rest or stress-induced moderate-to-severe secondary mitral regurgitation. The SE response was graded on a scale from 0 (all steps normal) to 5 (all ABCDE+ steps abnormal). Results The mean ABCDE score was 1.5±1.2, ranging from 0 (n=59, 22.3%) to 5 (n=2, 0.8%) (see distribution of scores in Figure 1A). Abnormal results were observed in 21 subjects (7.9%) for A, 86 (32.5 %) for B, 147 (55.5%) for C, 42/102 (41.2%) for D, and 101 (38.1%) for E steps. Step F was abnormal in 22/188 (11.8%) at rest and in 16/107 (14.9%) at peak stress. The predominant "solitary phenotypes" (only one step abnormal) were impaired LV contractile function phenotype (step C in 47, 51.1%) followed by chronotropic insufficiency (step E in 17, 18.5%) and congestive phenotype (step B in 17, 18.5%) (see Figure 1B). The most frequent combined phenotype was BCE – congestive phenotype with impaired ventricular and heart rate reserves (28 [62.2%]). Notably, 38 patients (14.3%) demonstrated improved regional contractility, while 27 patients (10.2%) showed new regional wall motion abnormality (see Table). Conclusion Non-ischemic HF patients with abnormal EF exhibit a broad spectrum of phenotypes. Impaired left ventricular contractility, interstitial congestion, and chronotropic insufficiency are the most frequent abnormalities detected by ABCDE-SE. Up to one-quarter of such patients demonstrate normal SE results. This comprehensive approach paves the way for personalized, SE-guided therapy.

Abstract Background It has been hypothesized that combined heart and kidney transplantation (HKT) may lead to immune modulation and attenuation of cardiac allograft vasculopathy (CAV) progression. Sirolimus (SRL) has been shown to mitigate the progression of CAV and confer renal protection. With the increasing use of SRL as primary immunosuppression in heart transplant (HT) recipients, the effect of HKT on CAV progression compared to HT-only remains undetermined. Purpose We sought to investigate the patterns of conversion from calcineurin inhibitors (CNI) to SRL, and its impact on CAV progression and outcomes in HKT compared to HT-only in a cohort with frequent use of SRL as primary immunosuppression. Methods A cohort of 302 patients who underwent either HT only (n=262) or combined HKT (n=40) was analyzed. CAV progression was assessed by measuring the delta (Δ) annual change in plaque volume (PV) normalized to vessel length (PV/VL in mm3/mm) and plaque index (PI) (%) (calculated as the PV to VV ratio) between baseline and last follow-up coronary intravenous ultrasound (IVUS). Clinical adverse outcomes included all-cause death and CAV-associated events. Secondary outcomes included differences in renal function and incidence of SRL-associated proteinuria (defined as Δ urine protein ≥300 mg/24 h at 1 year after conversion to SRL) between HT-only and HKT recipients. Results Overall, 217 (72%) patients were converted from CNI to SRL as primary immunosuppression. HT recipients were more likely to be converted to SRL than combined HKT recipients (74% vs. 55%, P=0.01). HKT was associated with significantly higher ΔPV/VL (P=0.01) and a trend toward a higher ΔPI (P=0.06) than HT-only, but this association was markedly attenuated after adjustment to SRL conversion. HKT was associated with similar risk of death (adjusted hazard ratio [HR] 0.69, 95%CI: 0.28-1.71, P=0.43) and CAV-related events (adjusted HR 0.83, 95% CI: 0.30-2.31, P=0.72). Conversion to SRL was significantly associated with decreased risk of death and CAV-related events in the overall cohort. This association was not modified by the type of organ transplantation (Pinteraction=NS), and without a significant effect on estimated glomerular filtration rate (eGFR) or proteinuria. Conclusions HKT recipients compared to HT-only were less likely to be converted from CNI to SRL-based immunosuppression and had a greater CAV progression but without significant differences in all-cause mortality or CAV-related events. The clinical benefit and safety of conversion to SRL appeared similar in the HKT and isolated HT cohorts.

Abstract Background In light of the updated lowered threshold for diagnosing pulmonary hypertension (PH), the reversibility of precapillary PH with left ventricular assist device (LVAD) and the associated post heart transplantation (HT) outcomes remain unclear. Purpose and methods Using data from the United Network for Organ Sharing database, we aimed to investigate predictors of persistent precapillary PH in HT recipients bridged with LVAD, and examine the interrelated post-HT survival, using the updated pulmonary vascular resistance (PVR) cutoff of >2 WU for precapillary PH. Results Among 2169 HT recipients bridged with LVAD, 1299 had PVR>2 at baseline; 551 (42.4%) of whom normalized their PVR≤2 and 748 (57.6%) remained with elevated PVR>2 after LVAD implantation. Female sex (adjusted odds ratio [aOR] 2.22, 95% confidence interval [CI]:1.61-3.07, p<0.001) and inotropes-treatment at-listing (aOR 1.31, 95% CI: 1.03-1.66, p=0.028) were associated with persistently elevated PVR post LVAD. Conversely, longer duration of LVAD support (aOR 0.74, 95% CI: 0.65-.84, p<0.001) and use of HeartMate 2 (aOR 0.74, CI: 0.59-0. 93, p=0.011) were protective against persistently elevated PVR post-LVAD. Persistently elevated PVR >2 post-LVAD was associated with increased risk of death compared to those who normalized their PVR (adjusted hazard ratio [aHR] 1.26, 95% CI: 1.01-1.57, p=0.037). However, normalized PVR post-LVAD group had comparable survival to those with PVR≤2 at baseline (aHR 0.76, 95% CI: 0.57-1.02, p=0.07). Conclusions Many HT recipients bridged with LVAD remain with PVR>2 post-LVAD implantation, which is associated with increased risk of death post-HT compared to patients with normalized PVR post-LVAD.

Abstract Background Left Ventricular Assist Devices (LVADs) and heart transplantation stand out as the two well-established and effective therapeutic approaches for managing patients with advanced heart failure. Exercise-based cardiac rehabilitation (EBCR) has been demonstrated to improve functional capacity in patients with LVAD. Purpose We aim to assess the efficacy and safety of EBCR in patients with LVAD. Also, to compare high-intensity (HIT) versus moderate-intensity (MIT) EBCR regimens in patients with LVAD. Methods A systematic review and meta-analysis synthesizing evidence from randomized controlled trials (RCTs) studies obtained from PubMed, Embase Cochrane, Scopus, and WOS until January 2024. We used the fixed-effects model to report dichotomous outcomes using risk ratio (RR) and continuous outcomes using standardized mean difference (SMD) with a 95% confidence interval (CI). Results Six RCTs with 160 patients were included. There was no significant difference between EBCR and standard care regarding peak VO2 change [SMD: 0.24 with 95% CI (-0.14, 0.62), P= 0.21] and six-minute walk distance (6-MWD) change [SMD: 0.28 with 95% CI (-0.11, 0.66), P= 0.16]. Also, there was no significant difference between HIT and MIT exercise regarding peak VO2 change [SMD: 0.20 with 95% CI (-0.41, 0.82), P= 0.52] and 6-MWD change [SMD: 0.07 with 95% CI (-0.54, 0.69), P= 0.81]. Moreover, EBCR was associated with a significant decrease in the incidence of any adverse events when compared to usual care with [RR: 0.80 with 95% CI (0.65, 0.99), P= 0.04], while there was no significant difference between HIT and MIT exercise regarding the incidence of any adverse events [RR: 0.38 with 95% CI (0.02, 9.22), P= 0.55]. Conclusion EBCR did not improve functional capacity in patients with LVAD, with no significant effect on peak VO2 or 6-MWD.