Paradigm shift in myocarditis treatment.

Although most cases of myocarditis are self-limiting with a gradual improvement in cardiac function, the involvement of myocarditis in sudden cardiac death among children and young adults remains substantial, with rates of 3-17 % and 8.6-12 %, respectively. Moreover, the risk of developing chronic dilated cardiomyopathy ranges from 21 % to 30 % in all cases confirmed by biopsy. Current therapeutic strategies for myocarditis and its complications range from standard supportive care for heart failure and arrhythmias to etiologically oriented, case-based therapeutic options. For example, immunosuppression is indicated only in certain forms of acute myocarditis with clinical or endomyocardial biopsy evidence of immune checkpoint inhibitor-induced myocarditis and autoimmune diseases, including giant cell myocarditis, eosinophilic myocarditis, vasculitis, or cardiac sarcoidosis. However, our views on myocarditis treatment have changed considerably over the past two decades, thanks to the emergence of regenerative cells/tissues as well as drug and gene delivery systems. Cell-based therapies are now growing in popularity in any field of medicine. Studies evaluating the therapeutic efficacy of different stem cells in the treatment of acute myocarditis and its chronic complications have shown that although the experimental characteristics varied from study to study, in general, these strategies reduced inflammation and myocardial fibrosis while preventing myocarditis-induced systolic dysfunction and adverse remodeling in animal models.

The usefulness of chest drain and epicardial pacing wire culture for diagnosing mediastinitis after open-heart surgery.

PURPOSE: Culture of extracted drains or epicardial pacing wires is an easy and noninvasive method for detecting mediastinitis after open-heart surgery, although studies on its sensitivity and specificity are limited. We, therefore, investigated the usefulness of this approach for diagnosing mediastinitis. METHODS: We retrospectively studied the culture results of drains and epicardial pacing wires extracted from 3308 patients. Prediction models of mediastinitis with and without culture results added to clinical risk factors identified by a logistic regression analysis were compared. RESULTS: The incidence of mediastinitis requiring surgery was 1.89% (n = 64). Staphylococcus was the causative bacterium in 64.0% of cases. The sensitivity, specificity, and positive and negative predictive values of positive culture results were 50.8%, 91.8%, 10.7%, and 99.0%, respectively. Methicillin-resistant Staphylococcus aureus had the highest positive predictive value (61.5%). A multivariate analysis identified preoperative hemodialysis (OR 5.40 [2.54-11.5], p < 0.01), long operative duration (p < 0.01), postoperative hemodialysis (OR 2.25 [1.01-4.98], p < 0.05), and positive culture result (OR 10.2 [5.88-17.7], p < 0.01) as independent risk factors. The addition of culture results to pre- and postoperative hemodialysis and a lengthy operative time improved the prediction of mediastinitis. CONCLUSIONS: A culture survey using extracted drains and epicardial pacing wires may provide useful information for diagnosing mediastinitis.

Three-step surgical management algorithm for annular rupture in transcatheter aortic valve replacement.

Objective: Whereas transcatheter aortic valve replacement is widely implemented, annular rupture is a devastating complication and could be highly mortal. However, owing to its rare incidence, the optimal treatment algorithm has not been established. Thus, we evaluated the feasibility and effectiveness of a 3-step algorithm to treat annulus rupture. Methods: From 2009 to 2022, 8 patients of 1083 transcatheter aortic valve implantation (0.8%) developed annulus rupture and were treated with the three-step algorithm. The algorithm was composed of a first step (pericardial drainage and protamine neutralization with blood pressure control), second step (manual hemostatic compression via full/partial sternotomy), and a third step (conservative treatment or radical surgical correction). Results: The median age at the procedure was 85 (78-88) years and 7 female patients were included in this study. Two (25%) patients had end-stage renal failure under hemodialysis, and median Society of Thoracic Surgeons score was 8.9% (2.1%-23.2%). The implanted transcatheter heart valves (THVs) were 7 balloon-expandable THVs and 1 self-expandable THV with balloon postdilatation. Under this strategy, 8 (100%) patients underwent pericardial drainage as first step and 5 patients achieved hemostasis. Of these, patient 1 demonstrated bleeding from left sinus of Valsalva and required a Bentall procedure. Although the etiology of this phenomenon was not investigated by contrast-enhanced computed tomography, it might be derived from pseudoaneurysm rupture or delayed annular rupture. In 2 patients, the second step treatment was needed for hemostasis. Third-step treatment was conducted in 1 patient. Postoperatively, 6 patients could be discharged without critical complications whereas 2 patients died during the hospitalization. There were no other complications during the followed-up (584 [7-1614]) days. Conclusions: In accordance with the three-step algorithm, 6 patients, including those with high-risk or inoperative status, survived.

Clinical Outcomes and Factors Associated With Aortic Shrinkage After Thoracic Endovascular Aortic Repair for Aneurysmal Chronic Aortic Dissection.

PURPOSE: The effectiveness of thoracic endovascular aortic repair (TEVAR) for chronic aortic dissection (AD) with aneurysmal degeneration remains controversial. We retrospectively investigated clinical outcomes and assessed predictors of aortic shrinkage after TEVAR for chronic aneurysmal AD. MATERIALS AND METHODS: Between January 2010 and December 2021, 70 patients with double-barrel-type chronic AD were enrolled. Major intimal tears in thoracic aorta were covered by stent graft. Early and late clinical outcomes, and diameter change of downstream aorta during follow-up period were reviewed. Subsequently, factors associated with aortic shrinkage were assessed by logistic regression analysis. RESULTS: Mean age was 63 (interquartile range [IQR]: 54-68) years, 54 (80%) men, median duration from AD onset was 4 (IQR: 1-10) years, and maximum aortic diameter was 53 (IQR: 49-58) mm. Supra-aortic debranching procedure was required in 57 (81%) patients. Early aorta-related death occurred in 2 (3%) patients. Both stroke and spinal cord ischemia occurred in 1 (2%) patient. Five-year freedom rates from aorta-related death and reintervention were 96% and 51%, respectively. Sixty-four patients underwent follow-up computed tomography (84%) 1 year after TEVAR, with 33 (52%) achieving aortic shrinkage. In multivariable analysis, duration from AD onset (per year) (odds ratio [OR]: 0.82, 0.70-0.97; p=0.017) and maximum aortic-diameter ratio between aortic arch and descending aorta (per 0.1) (morphologic index; OR: 1.34, 1.04-1.74; p=0.023) were independent aortic shrinkage predictors. CONCLUSIONS: Thoracic endovascular aortic repair for chronic AD with aneurysmal degeneration achieved satisfactory survival outcomes, but with a considerable reintervention rate. Duration from AD onset and preoperative aortic morphology could affect post-TEVAR aortic shrinkage. Earlier intervention could lead to better aortic shrinkage. CLINICAL IMPACT: Thoracic endovascular aortic repair for chronic aortic dissection with aneurysmal degeneration showed low incidence of early and late aorta-related death. By contrast, aortic shrinkage rate was low with high incidence of reintervention to the residual downstream aorta. According to the assessment of preoperative variables, chronicity and aortic morphology could predict postoperative aortic shrinkage.

Midterm outcomes after surgical aortic valve replacement with the INSPIRIS RESILIA from a multicenter AVR registry.

BACKGROUND: There have been few reports on the mid- to long-term safety and efficacy validation of the INSPIRIS RESILIA aortic bioprosthesis (Edwards Lifesciences LLC, Irvine, CA, USA) in Japan. Herein, we report the mid-term results of surgical aortic valve replacement (AVR) for aortic stenosis using INSPIRIS and evaluate the hemodynamics compared to the CEP Magna series from the multicenter AVR registry (the ACTIVIST registry). METHODS: Of the 1967 patients who underwent surgical or transcatheter AVR from the ACTIVIST registry, 66 patients who underwent isolated surgical AVR with INSPIRIS by December 2020 were included in this study, and the early and mid-term results were evaluated. Hemodynamics were evaluated by comparing 272 patients undergoing isolated surgical AVR with the Magna group using propensity score matching. RESULTS: The mean age was 74.0 ±â€¯7.8 years, and 48.5 % were women. In-hospital mortality was 1.5 %, and the survival rates at 1- and 2-years were 95.2 % and 95.2 %, respectively. After propensity score matching, echocardiographic findings at discharge demonstrated that peak velocity and mean pressure gradient in the INSPIRIS group were comparable, while the effective orifice area in the INSPIRIS group was significantly larger than those in the Magna group (p = 0.048). A patient-prosthesis mismatch at discharge was significantly lower in the INSPIRIS group (11.8 %) than in the Magna group (36.4 %) (p = 0.004). CONCLUSIONS: Surgical AVR with INSPIRIS was performed safely and the mid-term results were satisfactory. The hemodynamics of INSPIRIS were comparable to those of Magna.

Successful surgery for secondary aortoduodenal fistula based on 18F-fluorodeoxyglucose positron emission tomography/computed tomography findings.

Secondary aortoduodenal fistula (sADF) is a critical late complication of abdominal aortic repair, requiring complete excision of the infected prosthesis. However, this is a highly invasive procedure for the elderly. We describe a case of sADF repair in a 76-year-old woman. Through 18F (fluorine-18)-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography mapping, focal high FDG uptake at the sADF site, right medial limb, and ligated left lateral limb of the prosthesis was detected. The duodenal and prosthetic grafts were partially resected. The proximal and distal anastomotic segments, with no FDG uptake, were retained. The abdominal aorta was reconstructed using a bovine pericardium roll and femorofemoral bypass. Thus, FDG positron emission tomography/computed tomography mapping of the infection site could help in such cases.

A Risk Model for 1-Year Mortality After Transcatheter Aortic Valve Replacement From the J-TVT Registry.

Background: Although transcatheter aortic valve replacement (TAVR) has demonstrated favorable outcomes in randomized studies, there remains a sizable group of patients in whom TAVR may be futile. Characterizing the survival rate in a wide array of patients undergoing TAVR can help develop effective strategies for improving the allocation of medial resources. Objectives: The aim of this study was to develop a risk model to estimate 1-year mortality after TAVR from a representative nationwide registry in Japan. Methods: The J-TVT (Japan Transcatheter Valve Therapies) registry contains complete data, including 1-year outcomes, on patients undergoing TAVR in Japan. A total of 17,655 patients underwent TAVR between 2013 and 2018. They were randomly divided into 2 groups in a 7:3 ratio to form a derivation cohort of 12,316 patients and a validation cohort of 5,339 patients. A risk model was constructed for 1-year mortality in the derivation cohort, and its discrimination and calibration were assessed in the validation cohort. Results: The mean age of all registered patients was 84.4 years, and 68.8% were women. The mean body size area was 1.43 m2, and the mean Society of Thoracic Surgeons Predicted Risk of Mortality score was 7.3%. The estimated 1-year survival was 91.8%; 202 and 1,316 deaths were observed at 30 days and 1 year, respectively; The estimated C index for the developed model was 0.733 (95% CI: 0.709-0.757) in the validation cohort, with good calibration. Conclusions: A prediction model for 1-year survival following TAVR derived from a national clinical database performed well and should aid physicians managing TAVR patients.

Efficacy of a Protective Sheet for Reducing Ocular Radiation Exposure During Transcatheter Aortic Valve Implantation.

BACKGROUND: The use of hybrid operating rooms (HOR) for transcatheter aortic valve implantation (TAVI) has increased, so radiation exposure during procedures that use X-ray fluoroscopy is a fundamental problem not only for patients but also for surgeons and interventional cardiologists, increasing the risk of cataracts among operators. We investigated the efficacy of leaded glasses and protective sheets for ocular radiation protection.Methods and Results: Between January 2020 and February 2021 we enrolled 54 TAVI procedures using the transfemoral approach. The subjects were divided into a curtain protection group (Group C, n=20), glass protection group (Group G, n=17), and sheet protection group (Group S, n=17). The cumulative dose (CD) of the operators showed a decreasing trend in Group S compared with the other two groups. The CD normalized by dose area product (CD/DAP) of the operators was significantly reduced in Group S compared with Group C. However, Group G showed no significant difference compared with Group C. Regarding the distribution of CD/DAP, Group S had a significantly lower distribution than that in groups C and G. CONCLUSIONS: Protective sheets provide more stable radiation protection than conventional curtains or leaded glasses.

Short-Term Outcomes of Magnetically Levitated Left Ventricular Assist Device in Advanced Heart Failure　- The Japanese Cohort.

BACKGROUND: The superiority of a fully magnetically levitated centrifugal-flow left ventricular assist device (LVAD) in terms of overall survival, stroke events and pump thrombosis has been demonstrated in previous international analyses, so we evaluated a Japanese cohort for the same.Methods and Results: This retrospective observational study was conducted at Osaka University Medical Hospital and the National Cerebral and Cardiovascular Center in Japan. A total of 75 consecutive patients who underwent HeartMate3 (HM3) implantation were included. The primary endpoint was on-device survival, and the secondary endpoint was the incidence of LVAD-related complications at 2 years. All parameters were compared with those of the previously performed HeartMate II (HMII) implantation in 197 cases. The on-device survival rates were 94.7% and 92.3% in the HM3 and HMII groups, respectively, at the 2-year follow-up (P=0.62). The rehospitalization-free rate after implantation was 61.8% in the HM3 group, which was significantly higher than that in the HMII group (relative risk, 0.35; 95% confidence interval [CI], 0.23-0.55; P<0.0001). Event-free survival rates from cerebral cerebrovascular events and pump thrombosis in the HM3 group were significantly higher than those in the HMII group, at 97.2% and 100%, respectively (relative risk, 0.14; 95% CI 0.03-0.58); P=0.0015 and relative risk, not calculated; P=0.049, respectively). CONCLUSIONS: Satisfactory short-term outcomes were observed after HM3 implantation in a Japanese cohort.

Impact of the Patency of Inferior Mesenteric Artery on 7-Year Outcomes After Endovascular Aneurysm Repair.

PURPOSE: The impact of preoperative patent inferior mesenteric artery (IMA) on late outcomes following endovascular aneurysm repair (EVAR) remains unclear. This study aimed to investigate the specific influence of IMA patency on 7-year outcomes after EVAR. MATERIALS AND METHODS: In this retrospective cohort study, 556 EVARs performed for true abdominal aortic aneurysm cases between January 2006 and December 2019 at our institution were reviewed. Endovascular aneurysm repairs performed using a commercially available device with no type I or type III endoleak (EL) during follow-up and with follow-up ≥12 months were included. A total of 336 patients were enrolled in this study. The cohort was divided into the patent IMA group and the occluded IMA group according to preoperative IMA status. The late outcomes, including aneurysm sac enlargement, reintervention, and mortality rates, were compared between both groups using propensity-score-matched data. RESULTS: After propensity score matching, 86 patients were included in each group. The median follow-up period was 56 months (interquartile range: 32-94 months). The incidence of type II EL at discharge was 50% in the patent IMA group and 19% in the occluded IMA group (p<0.001). The type II EL from IMA and lumbar arteries was significantly higher in the patent IMA group than in the occluded IMA group (p<0.001 and p=0.002). The rate of freedom from aneurysm sac enlargement with type II EL was significantly higher in the occluded IMA group than in the patent IMA group (94% vs 69% at 7 years; p<0.001). The rate of freedom from reintervention was significantly higher in the occluded IMA group than in the patent IMA group (90% vs 74% at 7 years; p=0.007). Abdominal aortic aneurysm-related death and all-cause mortality did not significantly differ between groups (p=0.32 and p=0.34). CONCLUSIONS: Inferior mesenteric artery patency could affect late reintervention and aneurysm sac enlargement but did not have a significant impact on mortality. Preoperative assessment and embolization of IMA might be an important factor for improvement in late EVAR outcomes. CLINICAL IMPACT: The preoperative patency of the inferior mesenteric artery was significantly associated with a higher incidence of sac enlargement and reintervention with type II endoleak following endovascular aneurysm repair, even after adjustment for patient background. Preoperative assessment and embolization of inferior mesenteric artery might be an important factor for improvement in late EVAR outcomes.

A Case of Ascending Aortic Replacement and Aortic Valve Replacement in a Patient with Giant Pseudoaneurysm of the Ascending Aorta due to Prosthetic Valve Endocarditis after Transcatheter Aortic Valve Replacement Using Evolut PRO.

An 82-year-old man who underwent transcatheter aortic valve replacement (TAVR) using a 34-mm Evolut PRO (Medtronic, Minneapolis, MN, USA) for severe aortic stenosis 21 months previously presented with fever. Transesophageal echocardiography showed thickening of the valve leaflets of the transcatheter heart valve and movable structures such as verrucae on the upper edge of the Evolut PRO stent. Contrast-enhanced cardiac computed tomography showed a 72-mm saccular pseudoaneurysm on the dorsal aspect of the ascending aorta at the superior border of the Evolut PRO stent. Because of a suspected infected aortic aneurysm caused by prosthetic valve endocarditis (PVE), we performed aortic valve replacement using 23 mm Avalus (Medtronic, Minneapolis, MN, USA) and ascending aortic replacement using 26 mm Gelweave (Vascutek Terumo Inc, Scotland, UK). The postoperative course was uneventful. This report highlights that patients with PVE after TAVR may develop pseudoaneurysms of the ascending aorta.

A Case of TAV-in-SAV in a Patient with Structural Valve Deterioration after Surgical Aortic Valve Replacement with the INSPIRIS RESILIA Valve.

The INSPIRIS RESILIA valve is designed to dilate its valve annulus in transcatheter aortic valve-in-surgical aortic valve (TAV-in-SAV), a catheter therapy for biological valve deterioration. RESILIA tissue has improved anti-calcification properties. An 83-year-old man on hemodialysis undergoing surgical aortic valve replacement (SAVR) with a 25-mm INSPIRIS for severe aortic stenosis 22 months ago presented with general malaise. Transthoracic echocardiography revealed severe bioprosthetic stenosis (peak velocity: 3.5 m/s, mean pressure gradient: 32 mmHg, and effective orifice area: 0.45 cm2) and severely reduced left ventricular function (ejection fraction: 17%). Because redo-SAVR was extremely risky (society of thoracic surgeons [STS] risk score: 31%), the patient underwent transfemoral-TAV-in-SAV using a 26-mm SAPIEN 3️. Pre- and postoperative computed tomography showed that the internal diameter of the INSPIRIS had expanded from 22.2 mm to 24.2 mm. This case demonstrated the dilatable design of INSPIRIS but not the durability of RESILIA tissue.

A Case of CABG in a Patient with High Risk of Coronary Obstruction during TAV-in-TAV.

A 94-year-old man who underwent transcatheter aortic valve (TAV) replacement 6 years ago was admitted because of exertional dyspnea. Transthoracic echocardiography revealed severe aortic regurgitation owing to TAV dysfunction. The patient was considered to have a high risk of occlusion of the sinus of Valsalva during TAV-in-TAV. Therefore, we performed TAV-in-TAV concomitant with coronary artery bypass grafting (CABG). The postoperative course was uneventful, and computed tomography 9 months later revealed patency of both the grafts. Concomitant CABG could be considered as one of the options in patients with a high risk of coronary occlusion during TAV-in-TAV.

Successful transfemoral-transcatheter aortic valve replacement in high-risk patients with a grade 4 atheroma in the ascending aorta: cerebral protection with a filter device.

Perioperative stroke is one of the most serious complications after transcatheter aortic valve replacement (TAVR), and it should be especially noted in patients with an atheroma in the ascending aorta. Here, we report the first experience of transfemoral (TF)-TAVR with the insertion of a filter device for two patients with severe aortic stenosis who were incidentally detected a grade 4 atheroma in the ascending aorta preoperatively. The patients had a favorable postoperative course without any cerebrovascular events or procedure-related complications.

Coronary access after repeat transcatheter aortic valve replacement in patients of small body size: A simulation study.

BACKGROUND: Coronary artery access after repeat transcatheter aortic valve replacement (TAV-in-TAV) is reportedly more difficult because leaflet displacement of the first transcatheter heart valve (THV) impairs coronary cannulation; however, its effects in small patients are unknown. This study aimed to simulate coronary accessibility after TAV-in-TAV in patients of small body size. METHODS: We retrospectively analyzed computed tomography scans after initial THV implantation and classified patients by THV and coronary artery location, valve-to-aorta distance, and valve-to-coronary distance. Risks were compared between the SAPIEN and CoreValve/Evolut series, among THV generations, and between bicuspid and tricuspid aortic valves in the CoreValve/Evolut series. RESULTS: A total of 254 patients (SAPIEN series, n = 164; CoreValve/Evolut series, n = 90) were enrolled. The average body surface area of the patients was 1.44 m2. Patients were classified as "feasible" (26%), "theoretically feasible with low risk" (19.7%), "theoretically feasible with high risk" (8.7%), or "unfeasible" (45.8%). The "unfeasible" rate was significantly higher in the CoreValve/Evolut series than in the SAPIEN series (78.9% vs 26.2%; P < .001). A significantly higher "unfeasible" rate was identified in the current model of SAPIEN (SAPIEN, 8.3%; SAPIENXT, 1.8%; SAPIEN3, 48.2%; P < .001), but not in the CoreValve/Evolut series (CoreValve, 83.3%; Evolut R, 80.0%; Evolut PRO, 71.4%; P = .587). Patients with a bicuspid aortic valve had a lower "unfeasible" rate compared to those with a tricuspid aortic valve (60.0% vs 86.2%; P = .014). CONCLUSIONS: Patients of small body size may have a high probability of "unfeasible" coronary access after TAV-in-TAV, especially when treated with current high-frame devices, suggesting the need for careful strategic planning for initial THV implantation.

Impact of radiation to the eye of operators during endo-cardiovascular surgery and the importance of protection.

OBJECTIVE: To verify the amount of radiation exposure to the eye of operators during endocardiovascular surgery (ECVS) in hybrid operating room (HOR), which increases the risk of cataracts in surgeons. METHODS: Fifty cases of ECVS (including 36 transcatheter aortic valve implantation and 14 thoracic endovascular repair) using the transfemoral approach performed from February 2020 to July 2020 were included. A measurement device was attached to the left side of the head of the operators and their assistants to measure the cumulative dose (CD) of intraoperative radiation exposure. The subjects were divided into the control group (Group C, n = 26), received conventional protection using the protective curtain in HOR and the protected group (Group R, n = 24), received conventional protection and protection sheet. The normalized CD by dose area product (CD/DAP) was evaluated. RESULTS: The CD/DAP of the surgeons was significantly decreased in Group R, averaging at 5.97 µSV/Gy cm2 in Group C group and 4.40 µSV/Gy cm2 in Group R (p < 0.01). Moreover, CD/DAP of the assistant was significantly reduced in the Group R, with an average of 1.87 µSV/Gy cm2 in the Group C and 1.01 µSV/Gy cm2 in Group R (p < 0.01). CONCLUSIONS: The radiation exposure to the surgeon's eye could be significantly reduced by protection sheet.

Cell barrier function of resident peritoneal macrophages in post-operative adhesions.

Post-operative adhesions are a leading cause of abdominal surgery-associated morbidity. Exposed fibrin clots on the damaged peritoneum, in which the mesothelial barrier is disrupted, readily adhere to surrounding tissues, resulting in adhesion formation. Here we show that resident F4/80HighCD206- peritoneal macrophages promptly accumulate on the lesion and form a 'macrophage barrier' to shield fibrin clots in place of the lost mesothelium in mice. Depletion of this macrophage subset or blockage of CD11b impairs the macrophage barrier and exacerbates adhesions. The macrophage barrier is usually insufficient to fully preclude the adhesion formation; however, it could be augmented by IL-4-based treatment or adoptive transfer of this macrophage subset, resulting in robust prevention of adhesions. By contrast, monocyte-derived recruited peritoneal macrophages are not involved in the macrophage barrier. These results highlight a previously unidentified cell barrier function of a specific macrophage subset, also proposing an innovative approach to prevent post-operative adhesions.

Epicardial placement of human MSC-loaded fibrin sealant films for heart failure: Preclinical efficacy and mechanistic data.

Mesenchymal stromal cell (MSC) transplantation has been investigated as an advanced treatment of heart failure; however, further improvement of the therapeutic efficacy and mechanistic understanding are needed. Our previous study has reported that epicardial placement of fibrin sealant films incorporating rat amniotic membrane-derived (AM)-MSCs (MSC-dressings) could address limitations of traditional transplantation methods. To progress this finding toward clinical translation, this current study aimed to examine the efficacy of MSC-dressings using human AM-MSCs (hAM-MSCs) and the underpinning mechanism for myocardial repair. Echocardiography demonstrated that cardiac function and structure were improved in a rat ischemic cardiomyopathy model after hAM-MSC-dressing therapy. hAM-MSCs survived well in the rat heart, enhanced myocardial expression of reparative genes, and attenuated adverse remodeling. Copy number analysis by qPCR revealed that upregulated reparative genes originated from endogenous rat cells rather than hAM-MSCs. These results suggest hAM-MSC-dressing therapy stimulates a secondary release of paracrine factors from endogenous cells improving myocardial repair ("secondary paracrine effect"), and cardiac M2-like macrophages were identified as a potential cell source of repair. We demonstrated hAM-MSCs increased M2-like macrophages through not only enhancing M2 polarization but also augmenting their proliferation and migration capabilities via PGE2, CCL2, and TGF-ß1, resulting in enhanced cardiac function after injury.