Extracardiac Prothrombotic Effects of COVID-19.

COVID-19 infection triggers a heightened inflammatory response which in turn, increases thrombosis and thromboembolism. Microvascular thrombosis has been detected in various tissue beds which may account for some of the multi-system organ dysfunction associated with COVID-19. Additional research is needed to understand which prophylactic and therapeutic drug regimens are best for the prevention and treatment of thrombotic complications of COVID-19.

Mechanical Circulatory Support in Patients With COVID-19 Presenting With Myocardial Infarction.

ST-segment elevation myocardial infarction (STEMI) complicating COVID-19 is associated with an increased risk of cardiogenic shock and mortality. However, little is known about the frequency of use and clinical impact of mechanical circulatory support (MCS) in these patients. We sought to define patterns of MCS utilization, patient characteristics, and outcomes in patients with COVID-19 with STEMI. The NACMI (North American COVID-19 Myocardial Infarction) is an ongoing prospective, observational registry of patients with COVID-19 positive (COVID-19+) with STEMI with a contemporary control group of persons under investigation who subsequently tested negative for COVID-19 (COVID-19-). We compared the baseline characteristics and in-hospital outcomes of COVID-19+ and patients with COVID-19- according to the use of MCS. The primary outcome was a composite of in-hospital mortality, stroke, recurrent MI, and repeat unplanned revascularization. A total of 1,379 patients (586 COVID-19+ and 793 COVID-19-) enrolled in the NACMI registry between January 2020 and November 2021 were included in this analysis; overall, MCS use was 12.3% (12.1% [n = 71] COVID-19+/MCS positive [MCS+] vs 12.4% [n = 98] COVID-19-/MCS+). Baseline characteristics were similar between the 2 groups. The use of percutaneous coronary intervention was similar between the groups (84% vs 78%; p = 0.404). Intra-aortic balloon pump was the most frequently used MCS device in both groups (53% in COVID-19+/MCS+ and 75% in COVID-19-/MCS+). The primary outcome was significantly higher in COVID-19+/MCS+ patients (60% vs 30%; p = 0.001) because of very high in-hospital mortality (59% vs 28%; p = 0.001). In conclusion, patients with COVID-19+ with STEMI requiring MCS have very high in-hospital mortality, likely related to the significantly higher pulmonary involvement compared with patients with COVID-19- with STEMI requiring MCS.

Sex Differences in Clinical Characteristics, Management Strategies, and Outcomes of STEMI With COVID-19: NACMI Registry.

Background: Women with ST-segment elevation myocardial infarction (STEMI) had worse outcomes than men prior to the COVID-19 pandemic. Although concomitant COVID-19 infection increases mortality risk in STEMI patients, no studies have evaluated sex differences in this context. Methods: The North American COVID-19 STEMI registry is a prospective, multicenter registry of hospitalized STEMI patients with COVID-19 infection. We compared sex differences in clinical characteristics, presentation, management strategies, and in-hospital mortality. Results: Among 585 patients with STEMI and COVID-19 infection, 154 (26.3%) were women. Compared to men, women were significantly older, had a higher prevalence of diabetes and stroke/transient ischemic attack, and were more likely to be on statins on presentation. Men more frequently presented with chest pain, whereas women presented with dyspnea. Women more often had STEMI without an identified culprit lesion than men (33% vs 18%, P < .001). The use of percutaneous coronary intervention was significantly higher in men, whereas medical therapy was higher in women. In-hospital mortality was 33% for women and 27% for men (P = .22). Conclusions: In patients presenting with STEMI in the context of COVID-19, the in-hospital mortality rate was 30% and similar for men and women. Lack of an identifiable culprit lesion was common in the setting of COVID-19 for both sexes but more likely in women (1/3 of women vs 1/5 of men). Evaluation of specific underlying etiologies is underway to better define the full impact of COVID-19 on STEMI outcomes and better understand the observed sex differences.

Extracardiac Prothrombotic Effects of COVID-19.

COVID-19 infection triggers a heightened inflammatory response which in turn, increases thrombosis and thromboembolism. Microvascular thrombosis has been detected in various tissue beds which may account for some of the multi-system organ dysfunction associated with COVID-19. Additional research is needed to understand which prophylactic and therapeutic drug regimens are best for the prevention and treatment of thrombotic complications of COVID-19.

Trends in Clinical Presentation, Management, and Outcomes of STEMI in Patients With COVID-19.

BACKGROUND: We previously reported high in-hospital mortality for ST-segment elevation myocardial infarction (STEMI) patients with COVID-19 treated in the early phase of the pandemic. OBJECTIVES: The purpose of this study was to describe trends of COVID-19 patients with STEMI during the course of the pandemic. METHODS: The NACMI (North American COVID-19 STEMI) registry is a prospective, investigator-initiated, multicenter, observational registry of hospitalized STEMI patients with confirmed or suspected COVID-19 infection in North America. We compared trends in clinical characteristics, management, and outcomes of patients treated in the first year of the pandemic (January 2020 to December 2020) vs those treated in the second year (January 2021 to December 2021). RESULTS: A total of 586 COVID-19-positive patients with STEMI were included in the present analysis; 227 treated in Y2020 and 359 treated in Y2021. Patients' characteristics changed over time. Relative to Y2020, the proportion of Caucasian patients was higher (58% vs 39%; P < 0.001), patients presented more frequently with typical ischemic symptoms (59% vs 51%; P = 0.04), and patients were less likely to have shock pre-PCI (13% vs 18%; P = 0.07) or pulmonary manifestations (33% vs. 47%; P = 0.001) in Y2021. In-hospital mortality decreased from 33% (Y2020) to 23% (Y2021) (P = 0.008). In Y2021, none of the 22 vaccinated patients expired in hospital, whereas in-hospital death was recorded in 37 (22%) unvaccinated patients (P = 0.009). CONCLUSIONS: Significant changes have occurred in the clinical characteristics and outcomes of STEMI patients with COVID-19 infection during the course of the pandemic.

Outflow graft obstruction in patients with the HM 3 LVAD: A percutaneous approach.

BACKGROUND: The use of the HeartMate 3 (HM3) left ventricular assist device (LVAD) is expanding. Despite being associated with lower rates of adverse events and increased survival, outflow graft obstruction (OGO) has been reported in patients with HM3. The incidence and best management of this serious complication remain unclear. METHODS: We describe six cases of HM3 OGO occurring in five patients in our institutional HM3 cohort. Four cases underwent computed tomography angiography and in two percutaneous angiography was directly performed to confirm the diagnosis. In four cases, percutaneous repair of the OG was performed using common interventional cardiology (IC) techniques. RESULTS: Our institutional incidence of OGO was 7% (event rate of 0.05 per patient year); much higher than the previously reported incidence of 1.6%. All cases occurred in the bend relief covered segment. Only two patients had apparent OG twisting, and in two, OGO occurred despite placement of an anti-twist clip at the time of implant. External compression seems to play a role in most cases. Balloon "graftoplasty" and stent deployment via the femoral artery alleviated the obstruction and normalized LVAD flow in all patients who underwent percutaneous repair. The use of self-expanding stents allowed for downsizing of the procedural access site to 10 Fr. No serious procedure-related complications occurred. CONCLUSION: OGO is common in HM3 patients, external compression due to biomaterial accumulated surrounding the OG is a common etiology. Percutaneous repair using standard IC techniques is safe and feasible in cases of compression with or without partial twisting.

Machine-Learning-Based In-Hospital Mortality Prediction for Transcatheter Mitral Valve Repair in the United States.

BACKGROUND: Transcatheter mitral valve repair (TMVR) utilization has increased significantly in the United States over the last years. Yet, a risk-prediction tool for adverse events has not been developed. We aimed to generate a machine-learning-based algorithm to predict in-hospital mortality after TMVR. METHODS: Patients who underwent TMVR from 2012 through 2015 were identified using the National Inpatient Sample database. The study population was randomly divided into a training set (n = 636) and a testing set (n = 213). Prediction models for in-hospital mortality were obtained using five supervised machine-learning classifiers. RESULTS: A total of 849 TMVRs were analyzed in our study. The overall in-hospital mortality was 3.1%. A naïve Bayes (NB) model had the best discrimination for fifteen variables, with an area under the receiver-operating curve (AUC) of 0.83 (95% CI, 0.80-0.87), compared to 0.77 for logistic regression (95% CI, 0.58-0.95), 0.73 for an artificial neural network (95% CI, 0.55-0.91), and 0.67 for both a random forest and a support-vector machine (95% CI, 0.47-0.87). History of coronary artery disease, of chronic kidney disease, and smoking were the three most significant predictors of in-hospital mortality. CONCLUSIONS: We developed a robust machine-learning-derived model to predict in-hospital mortality in patients undergoing TMVR. This model is promising for decision-making and deserves further clinical validation.

Recurrent Left Ventricular Thrombus Formation on Rivaroxaban Therapy in Cardiomyopathy and Liver Cirrhosis.

Left ventricular (LV) thrombus in patients with reduced LV systolic function carries significant thromboembolic risk. Direct oral anticoagulants are an attractive alternative to warfarin for LV thrombus management. However, there are not enough data regarding the safety and efficacy of direct oral anticoagulants for the treatment of LV thrombus. (Level of Difficulty: Beginner.).

Machine Learning Prediction Models for In-Hospital Mortality After Transcatheter Aortic Valve Replacement.

OBJECTIVES: This study sought to develop and compare an array of machine learning methods to predict in-hospital mortality after transcatheter aortic valve replacement (TAVR) in the United States. BACKGROUND: Existing risk prediction tools for in-hospital complications in patients undergoing TAVR have been designed using statistical modeling approaches and have certain limitations. METHODS: Patient data were obtained from the National Inpatient Sample database from 2012 to 2015. The data were randomly divided into a development cohort (n = 7,615) and a validation cohort (n = 3,268). Logistic regression, artificial neural network, naive Bayes, and random forest machine learning algorithms were applied to obtain in-hospital mortality prediction models. RESULTS: A total of 10,883 TAVRs were analyzed in our study. The overall in-hospital mortality was 3.6%. Overall, prediction models' performance measured by area under the curve were good (>0.80). The best model was obtained by logistic regression (area under the curve: 0.92; 95% confidence interval: 0.89 to 0.95). Most obtained models plateaued after introducing 10 variables. Acute kidney injury was the main predictor of in-hospital mortality ranked with the highest mean importance in all the models. The National Inpatient Sample TAVR score showed the best discrimination among available TAVR prediction scores. CONCLUSIONS: Machine learning methods can generate robust models to predict in-hospital mortality for TAVR. The National Inpatient Sample TAVR score should be considered for prognosis and shared decision making in TAVR patients.

Racial/Ethnic Disparities in Patients Undergoing Transcatheter Aortic Valve Replacement: Insights from the Healthcare Cost and Utilization Project's National Inpatient Sample.

PURPOSE: To identify racial/ethnic disparities in utilization rates, in-hospital outcomes and health care resource use among Non-Hispanic Whites (NHW), African Americans (AA) and Hispanics undergoing transcatheter aortic valve replacement (TAVR) in the United States (US). METHODS AND RESULTS: The National Inpatient Sample database was queried for patients ≥18 years of age who underwent TAVR from 2012 to 2014. The primary outcome was all-cause in hospital mortality. A total of 36,270 individuals were included in the study. The number of TAVR performed per million population increased in all study groups over the three years [38.8 to 103.8 (NHW); 9.1 to 26.4 (AA) and 9.4 to 18.2 (Hispanics)]. The overall in-hospital mortality was 4.2% for the entire cohort. Race/ethnicity showed no association with in-hospital mortality (P > .05). Though no significant difference were found between AA and NHW in any secondary outcome, being Hispanic was associated with higher incidence of acute myocardial infarction (aOR = 2.02; 95% CI, 1.06-3.85; P = .03), stroke/transient ischemic attack (aOR = 1.81; 95% CI, 1.04-3.14; P = .04), acute kidney injury (aOR = 1.65; 95% CI, 1.23-2.21; P < .01), prolonged length of stay (aOR = 1.18; 95% CI, 1.08-1.29; P < .01) and higher hospital costs (aOR = 1.27; 95% CI, 1.18-1.36; P < .01). CONCLUSION: There are significant racial disparities in patients undergoing TAVR in the US. Though in-hospital mortality was not associated with race/ethnicity, Hispanic patients had less TAVR utilization, higher in-hospital complications, prolonged length of stay and increased hospital costs.

Bivalirudin versus heparin in patients undergoing percutaneous peripheral interventions: A systematic review and meta-analysis.

BACKGROUND: Bivalirudin may be an effective alternative anticoagulant to heparin for use in percutaneous peripheral interventions. We aimed to compare the safety and efficacy of bivalirudin versus heparin as the procedural anticoagulant agent in patients undergoing percutaneous peripheral intervention. METHODS: For this meta-analysis and systematic review, we conducted a search in PubMed, Medline, Embase, and Cochrane for all the clinical studies in which bivalirudin was compared to heparin as the procedural anticoagulant in percutaneous peripheral interventions. Outcomes studied included all-cause mortality, all-bleeding, major and minor bleeding, and access site complications. RESULTS: Eleven studies were included in the analysis, totaling 20,137 patients. There was a significant difference favoring bivalirudin over heparin for all-cause mortality (risk ratio 0.58, 95% CI 0.39-0.87), all-bleeding (risk ratio 0.62, 95% CI 0.50-0.78), major bleeding (risk ratio 0.61, 95% CI 0.39-0.96), minor bleeding (risk ratio 0.66, 95% CI 0.47-0.92), and access site complications (risk ratio 0.66, 95% CI 0.51-0.84). There was no significant difference in peri-procedural need for blood transfusions (risk ratio 0.79, 95% CI 0.57-1.08), myocardial infarction (risk ratio 0.87, 95% CI 0.59-1.28), stroke (risk ratio 0.77, 95% CI 0.59-1.01), intracranial bleeding (risk ratio 0.77, 95% CI 0.29-2.02), or amputations (OR 0.75, 95% CI 0.53-1.05). CONCLUSION: Our meta-analysis suggests that bivalirudin use for percutaneous peripheral interventions is associated with lower all-cause mortality, bleeding, and access site complications as compared to heparin. Further large randomized trials are needed to confirm the current results.

Staged Percutaneous Intervention for Concurrent Chronic Total Occlusions in Patients With ST-Segment-Elevation Myocardial Infarction: A Systematic Review and Meta-Analysis.

BACKGROUND: Studies have shown that chronic total occlusion (CTO) in a noninfarct-related artery in patients with ST-segment-elevation myocardial infarction is linked to increased mortality. It remains unclear whether staged revascularization of a noninfarct-related artery CTO in patients with ST-segment-elevation myocardial infarction translates to improved outcomes. We performed a meta-analysis to compare outcomes between patients presenting with ST-segment-elevation myocardial infarction with concurrent CTO who underwent percutaneous coronary intervention of noninfarct-related artery CTO versus those who did not. METHOD AND RESULTS: We conducted an electronic database search of all published data. The primary end point was major adverse cardiovascular events. Secondary end points were all-cause mortality, cardiovascular mortality, myocardial infarction, repeat revascularization with either percutaneous coronary intervention or coronary artery bypass grafting, stroke, and heart failure readmission. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed. Random effects model was used and heterogeneity was considered if I2 >25. Six studies (n=1253 patients) were included in the analysis. There was a significant difference in major adverse cardiovascular events (OR, 0.54; 95% CI, 0.32-0.91), cardiovascular mortality (OR, 0.43; 95% CI, 0.20-0.95), and heart failure readmissions (OR, 0.57; 95% CI, 0.36-0.89), favoring the patients in the CTO percutaneous coronary intervention group. No significant differences were observed between the 2 groups for all-cause mortality (OR, 0.47; 95% CI, 0.22-1.00), myocardial infarction (OR, 0.78; 95% CI, 0.41-1.46), repeat revascularization (OR, 1.13; 95% CI, 0.56-2.27), and stroke (OR, 0.51; 95% CI, 0.20-1.33). CONCLUSIONS: In this meta-analysis, CTO percutaneous coronary intervention of the noninfarct-related artery in patients presenting with ST-segment-elevation myocardial infarction was associated with a significant reduction in major adverse cardiovascular events, cardiovascular mortality, and heart failure readmissions.

A Combination of Allogeneic Stem Cells Promotes Cardiac Regeneration.

BACKGROUND: The combination of autologous mesenchymal stem cells (MSCs) and cardiac stem cells (CSCs) synergistically reduces scar size and improves cardiac function in ischemic cardiomyopathy. Whereas allogeneic (allo-)MSCs are immunoevasive, the capacity of CSCs to similarly elude the immune system remains controversial, potentially limiting the success of allogeneic cell combination therapy (ACCT). OBJECTIVES: This study sought to test the hypothesis that ACCT synergistically promotes cardiac regeneration without provoking immunologic reactions. METHODS: Göttingen swine with experimental ischemic cardiomyopathy were randomized to receive transendocardial injections of allo-MSCs + allo-CSCs (ACCT: 200 million MSCs/1 million CSCs, n = 7), 200 million allo-MSCs (n = 8), 1 million allo-CSCs (n = 4), or placebo (Plasma-Lyte A, n = 6). Swine were assessed by cardiac magnetic resonance imaging and pressure volume catheterization. Immune response was tested by histologic analyses. RESULTS: Both ACCT and allo-MSCs reduced scar size by -11.1 ± 4.8% (p = 0.012) and -9.5 ± 4.8% (p = 0.047), respectively. Only ACCT, but not MSCs or CSCs, prevented ongoing negative remodeling by offsetting increases in chamber volumes. Importantly, ACCT exerted the greatest effect on systolic function, improving the end-systolic pressure-volume relation (+0.98 ± 0.41 mm Hg/ml; p = 0.016). The ACCT group had more phospho-histone H3+ (a marker of mitosis) cardiomyocytes (p = 0.04), and noncardiomyocytes (p = 0.0002) than did the placebo group in some regions of the heart. Inflammatory sites in ACCT and MSC-treated swine contained immunotolerant CD3+/CD25+/FoxP3+ regulatory T cells (p < 0.0001). Histologic analysis showed absent to low-grade inflammatory infiltrates without cardiomyocyte necrosis. CONCLUSIONS: ACCT demonstrates synergistic effects to enhance cardiac regeneration and left ventricular functional recovery in a swine model of chronic ischemic cardiomyopathy without adverse immunologic reaction. Clinical translation to humans is warranted.

Mesenchymal Stem Cells in Cardiology.

Cardiovascular disease (CVD) accounts for more deaths globally than any other single disease. There are on average 1.5 million episodes of myocardial infarction (heart attack) each year in the United States alone with roughly one-third resulting in death. There is therefore a major need for developing new and effective strategies to promote cardiac repair. Intramyocardial transplantation of mesenchymal stem cells (MSCs) has emerged as a leading contender in the pursuit of clinical intervention and therapy. MSCs are potent mediators of cardiac repair and are therefore an attractive tool in the development of preclinical and clinical trials. MSCs are capable of secreting a large array of soluble factors, which have had demonstrated effects on pathogenic cardiac remolding, fibrosis, immune activation, and cardiac stem cell proliferation within the damaged heart. MSCs are also capable of differentiation into cardiomyocytes, endothelial cells, and vascular smooth muscle cells, although the relative contribution of trilineage differentiation and paracrine effectors on cardiac repair remains the subject of active investigation.

Synergistic Effects of Combined Cell Therapy for Chronic Ischemic Cardiomyopathy.

BACKGROUND: Both bone marrow-derived mesenchymal stem cells (MSCs) and c-kit(+) cardiac stem cells (CSCs) improve left ventricular remodeling in porcine models and clinical trials. Using xenogeneic (human) cells in immunosuppressed animals with acute ischemic heart disease, we previously showed that these 2 cell types act synergistically. OBJECTIVES: To more accurately model clinical applications for heart failure, this study tested whether the combination of autologous MSCs and CSCs produce greater improvement in cardiac performance than MSCs alone in a nonimmunosuppressed porcine model of chronic ischemic cardiomyopathy. METHODS: Three months after ischemia/reperfusion injury, Göttingen swine received transendocardial injections with MSCs alone (n = 6) or in combination with cardiac-derived CSCs (n = 8), or placebo (vehicle; n = 6). Cardiac functional and anatomic parameters were assessed using cardiac magnetic resonance at baseline and before and after therapy. RESULTS: Both groups of cell-treated animals exhibited significantly reduced scar size (MSCs -44.1 ± 6.8%; CSC/MSC -37.2 ± 5.4%; placebo -12.9 ± 4.2%; p < 0.0001), increased viable tissue, and improved wall motion relative to placebo 3 months post-injection. Ejection fraction (EF) improved (MSCs 2.9 ± 1.6 EF units; CSC/MSC 6.9 ± 2.8 EF units; placebo 2.5 ± 1.6 EF units; p = 0.0009), as did stroke volume, cardiac output, and diastolic strain only in the combination-treated animals, which also exhibited increased cardiomyocyte mitotic activity. CONCLUSIONS: These findings illustrate that interactions between MSCs and CSCs enhance cardiac performance more than MSCs alone, establish the safety of autologous cell combination strategies, and support the development of second-generation cell therapeutic products.

Mesenchymal Stem Cells as a Biological Drug for Heart Disease: Where Are We With Cardiac Cell-Based Therapy?

Cell-based treatment represents a new generation in the evolution of biological therapeutics. A prototypic cell-based therapy, the mesenchymal stem cell, has successfully entered phase III pivotal trials for heart failure, signifying adequate enabling safety and efficacy data from phase I and II trials. Successful phase III trials can lead to approval of a new biological therapy for regenerative medicine.

Does transendocardial injection of mesenchymal stem cells improve myocardial function locally or globally?: An analysis from the Percutaneous Stem Cell Injection Delivery Effects on Neomyogenesis (POSEIDON) randomized trial.

RATIONALE: Transendocardial stem cell injection (TESI) with mesenchymal stem cells improves remodeling in chronic ischemic cardiomyopathy, but the effect of the injection site remains unknown. OBJECTIVE: To address whether TESI exerts its effects at the site of injection only or also in remote areas, we hypothesized that segmental myocardial scar and segmental ejection fraction improve to a greater extent in injected than in noninjected segments. METHODS AND RESULTS: Biplane ventriculographic and endocardial tracings were recorded. TESI was guided to 10 sites in infarct-border zones. Sites were mapped according to the 17-myocardial segment model. As a result, 510 segments were analyzed in 30 patients before and 13 months after TESI. Segmental early enhancement defect (a measure of scar size) was reduced by TESI in both injected (-43.7 ± 4.4%; n=95; P<0.01) and noninjected segments (-25.1 ± 7.8%; n=148; P<0.001; between-group comparison P<0.05). Conversely, segmental ejection fraction (a measure of contractile performance) improved in injected scar segments (19.9 ± 3.3-26.3 ± 3.5%; P=0.003) but not in noninjected scar segments (21.3 ± 2.6-23.5 ± 3.2%; P=0.20; between-group comparison P<0.05). Furthermore, segmental ejection fraction in injected scar segments improved to a greater degree in patients with baseline segmental ejection fraction <20% (12.1 ± 1.2-19.9 ± 2.7%; n=18; P=0.003), versus <20% (31.7 ± 3.4-35.5 ± 3.3%; n=12; P=0.33, between-group comparison P<0.0001). CONCLUSIONS: These findings illustrate a dichotomy in regional responses to TESI. Although scar size reduction was evident in all scar segments, scar size reduction and ventricular functional responses preferentially occurred at the sites of TESI versus non-TESI sites. Furthermore, improvement was greatest when segmental left ventricular dysfunction was severe.