Risk factors for delayed hemothorax in patients with rib fracture in the emergency department.

OBJECTIVES: Although rib fractures are a risk factor, not all rib fracture patients will develop delayed hemothorax. This study aimed to evaluate risk factors which can identify rib fracture patients in the emergency department who may develop delayed hemothorax. METHODS: Adult patients seen in the emergency room between January 2016 and February 2021 with rib fractures caused by blunt chest trauma were included in this retrospective observational study. Patients who underwent chest tube insertion within 2 days and those without follow-up chest radiographs within 2-30 days were excluded. We used a stepwise backward-elimination multivariable logistic regression model for analysis. RESULTS: A total of 202 patients were included in this study. The number of total (P < 0.001), lateral (P = 0.019), and displaced (P < 0.001) rib fractures were significantly associated with delayed hemothorax. Lung contusions (P = 0.002), and initial minimal hemothorax (P < 0.001) and pneumothorax (P < 0.001) were more frequently associated with delayed hemothorax. Age (adjusted odds ratio (aOR) 1.03, 95% confidence interval (CI) 1.00-1.06, P = 0.022), mechanical ventilator use (aOR 9.67, 95% CI 1.01-92.75, P = 0.049), initial hemothorax (aOR 2.21, 95% CI 1.05-4.65, P = 0.037) and pneumothorax (aOR 2.99, 95% CI 1.36-6.54, P = 0.006), and displaced rib fractures (aOR 3.51, 95% CI 1.64-7.53, P = 0.001) were independently associated with delayed hemothorax. CONCLUSIONS: Age, mechanical ventilation, initial hemo- or pneumothorax, and displaced rib fractures were risk factors for delayed hemothorax. Patients with these risk factors, and especially those with ≥2 displaced rib fractures, require close chest radiography follow-up of 2-30 days after the initial trauma.

Incidence and risk of stroke in Korean patients with congenital heart disease.

OBJECTIVES: The incidence and risk of ischemic stroke (IS) and hemorrhagic stroke (HS) in Korean patients with CHD have not been reported, therefore, we aimed to investigate this. MATERIALS AND METHODS: Participants were selected from the Korean National Health Insurance Service benefit records from 2006-2017. Cases were extracted using diagnosis codes related to CHD. Controls without CHD were selected through age- and sex-matched random sampling at a 1:10 ratio. RESULTS: The case and control groups included 232,203 and 3,024,633 participants, respectively. The median (interquartile range) follow-up period was 7.28 (3.59-8.73) years. The incidence rates of IS and HS per 100,000 person-years were much higher in cases than in controls (IS: 135 vs. 47; HS: 41.7 vs. 24.9). After adjusting for confounders, CHD was a risk factor for IS and HS (subdistribution HR; 1.96 and 1.71, respectively). In patients with CHD, the following risk factors were identified: diabetes, heart failure, and atrial fibrillation for any stroke; hypertension, atrial septal defects, and use of antiplatelet agents for IS only; and coronary artery bypass graft surgery for HS only. CONCLUSIONS: Korean patients with CHD have a high risk of stroke. A personalized preventive approach is needed to reduce the incidence of stroke in this population.

Aortic Valve Repair in Young Patients: A Single Patch Design for Leaflet Extension.

The surgical treatment for young patients with aortic valve diseases has not been standardized because of differences in the patients' growth. We aimed to investigate short-term results of aortic valve repair with leaflet extension techniques. From October 2017 to June 2020, we performed aortic valve repair with leaflet extension technique in 15 consecutive patients with a median age of 13 years (range, 33 months-27 years). Among them, all had moderate or severe aortic regurgitation (AR), eight had concomitant aortic stenosis, and 12 underwent prior cardiac operations. The leaflet patch design has been modified from separate patch design to single patch design. No early and late deaths were reported, no re-operations were performed, and temporary ectopic atrial arrhythmia was the only early complication noted. The patients were discharged with less than moderate AR after a median postoperative period of 5 (range, 3-7) days. All the patients were New York Heart Association class I after a median follow-up period of 17.3 (range, 4.4-34.6) months. However, two patients progressed to moderate AR postoperatively at 6 and 30 months, respectively, after which one was treated with single patch technique. Among the remaining patients, six had trace, six had mild, and one had mild-to-moderate AR. Aortic valve repair with leaflet extension is acceptable in young patients. Our single patch design was easy to manipulate and showed good short-term results. Long-term follow-up is required to further confirm the efficacy of this technique.

Satisfactory outcome with low activated clotting time in extracorporeal membrane oxygenation.

Optimal anticoagulation is critical for successful extracorporeal membrane oxygenation (ECMO) to counterbalance the activation of the coagulation system initiated by the blood-biosurface reaction and mechanical stresses. Systemic anticoagulation is achieved mainly with unfractionated heparin (UFH). Activated clotting time (ACT) is a widely used laboratory parameter to monitor anticoagulation. The therapeutic range of ACT is 180-220 s. We investigated the effect of a lower target ACT (<150 s) during ECMO on safety and outcomes and compared it with those of a conventional target ACT (180-200 s). In this single-center, retrospective study, we reviewed 72 adult patients treated with ECMO from March 2017 to October 2019. We included 43 patients after applying the exclusion criteria and divided them into the low ACT group (<150 s, n = 14, 32.6%) and conventional ACT group (≥150 s, n = 29, 67.4%). There was no difference in the successful weaning from ECMO support (50% vs. 62.1%, p = 0.452) and discharge (50% vs. 41.4%, p = 0.594) rates between the groups. One patient in the conventional ACT group had intracranial hemorrhage. There was one thromboembolic complication case with an intra-circuit thrombus. To date, anticoagulation remains a challenge during ECMO. Our results suggest that a lower target ACT does not necessarily increase the thromboembolic risk during ECMO management. Clinicians may consider anticoagulation with lower ACT target for some patients with careful assessment and close monitoring. Further prospective trials are warranted to validate these results.

The Risk Prediction of Coronary Artery Lesions through the Novel Hematological Z-Values in 4 Chronological Age Subgroups of Kawasaki Disease.

Background and Objectives: Most cases of Kawasaki disease (KD) occur between the ages of 6 months and 5 years. Differences in immunological reaction and CAL (coronary artery lesion) by the age subgroups classified according to the prevalence of KD and those particularly in the earlier life of KD should be investigated. Materials and Methods: The laboratory data of 223 infantile and 681 non-infantile KD cases from 2003 to 2018 at Korea University Hospital were retrospectively analyzed. Patients with KD were divided into infants and non-infants and further subdivided into four subgroups by age. The age-adjusted Z-values were compared among the subgroups. Febrile controls were identified as patients with fever for >5 days and who showed some of the KD symptoms. Results: IVIG (intravenous immunoglobulin) resistance at the age of 6 months or less was significantly lower than that at the ages of 7-12 months and 13-60 months (respectively, p < 0.05). The significant risk factors for CAL in total KD patients were age, incomplete KD, post-IVIG fever, IVIG resistance, convalescent Z-eosinophil, and subacute platelet (p < 0.05). The significant risk factors for CAL at the age of 6 months or less were IVIG resistance, acute Z-neutrophil, subacute Z-neutrophil, subacute NLR (neutrophil to lymphocyte ratio), and subacute platelet (respectively, p < 0.05). Conclusion: Younger age and incomplete presentation in KD can be independent risk factors for CAL. The immune reactions of KD at a younger age are more tolerated compared with those at older ages during the acute phase. The immune response at the age of 6 months or less showed immune tolerance in terms of incomplete presentation and IVIG responsiveness. The risk factors such as IVIG resistance, subacute platelet, subacute NLR, and acute or subacute Z-neutrophil at the age of 6 months or less can be very useful parameters to predict CAL in young, incomplete KD.

Current Status of Pediatric Critical Care in Korea: Results of 2015 National Survey.

BACKGROUND: The aim of this study was to describe the structure, organization, management, and staffing of pediatric critical care (PCC) in Korea. METHODS: We directed a questionnaire survey for all Upper Grade General Hospitals (n = 43) in Korea in 2015. The first questionnaire was mainly about structure, organization, and staffing and responses were obtained from 32 hospitals. The second questionnaire was mainly about patients and management. Responses to second questionnaire were obtained from 18 hospitals. RESULTS: Twelve from 32 Upper Grade General Hospitals had pediatric intensive care units (PICUs) and 11 of them had the PICU which was exclusive for children. Total number of PICU beds in Korea was 113. The ratio of the number of PICU beds to the number of children was 1:77,460 in Korea and this ratio is lower than that of other developed countries. The mean number of beds in the PICUs was 9.4 ± 9.3 (range, 2-30). There were 16 medical doctors who were assigned for PCC and only 5 of them were full time pediatric intensivists. In the 18 Upper Grade General Hospitals that responded to the second questionnaire survey, there were 97 patients in the PICUs with an average number of 5.7 ± 7.2 (range, 0-22) on the survey day. The mean age of the patients was 3.4 ± 5.6 years. The mean length of hospital stay was 82 ± 271 days. The mean Pediatric Risk of Mortality score III was 9.4 ± 7.8 at the time of admission to the PICUs. CONCLUSION: There is a considerable shortage of PICU beds compared to those in developed countries. In addition, the proportion of PICUs with PCC specialists is much lower than those in the US and European countries.

Different effects of five depigmentary compounds, rhododendrol, raspberry ketone, monobenzone, rucinol and AP736 on melanogenesis and viability of human epidermal melanocytes.

Numerous medications are used to treat hyperpigmentation. However, several reports have indicated that repeated application of some agents, such as rhododendrol (RD), raspberry ketone (RK) and monobenzone (MB), can be toxic to melanocytes. Although these agents had severe side effects in human trials, no current in vitro methods can predict the safety of such drugs. This study assessed the in vitro effects of five depigmentary compounds including leukoderma-inducing agents. In particular, we determined the effects of different concentrations and exposure times of different depigmentary agents on cell viability and melanogenesis in the presence and absence of ultraviolet B (UVB) radiation. Concentrations of RD, RK and MB that inhibit melanogenesis are similar to concentrations that are cytotoxic; however, concentrations of rucinol (RC) and AP736 that inhibit melanogenesis are much lower than concentrations that are cytotoxic. Furthermore, the concentrations that cause toxic effects depend on exposure duration, and prolonged exposure to RD, RK and MB had more cytotoxic effects than prolonged exposure to RC and AP736. The cytotoxic effects of RD and RK appear to be mediated by apoptosis due to increased expression of caspase-3 and caspase-8; UVB radiation increased the cytotoxicity of these agents and also increased caspase activity. Our results indicate that different leukoderma-inducing compounds have different effects on the viability of normal epidermal melanocytes and suggest that the in vitro assay used here can be used to predict whether an investigational compound that induces leukoderma may lead to adverse effects in human trials.

Unintended Pulmonary Artery Ligation during PDA Ligation.

A 10-day-old boy was transferred to our hospital due to tachypnea. Patent ductus arteriosus (PDA), 4.8 mm in diameter, with small ASD was diagnosed on echocardiography. Surgical ligation of the ductus was performed after failure of three cycles of ibuprofen. However, the ductus remained open on routine postoperative echocardiography on the second postoperative day, and chest CT revealed inadvertent ligation of the left pulmonary artery (LPA) rather than the PDA. Emergent operation successfully reopened the clipped LPA and ligated the ductus on the same (second postoperative) day.Mechanical ventilator support was weaned on postoperative day 21, and the baby was discharged on postoperative day 47 with a normal left lung shadow.

Characteristics of aortic valve dysfunction and ascending aorta dimensions according to bicuspid aortic valve morphology.

OBJECTIVE: To characterize aortic valve dysfunction and ascending aorta dimensions according to bicuspid aortic valve (BAV) morphology using computed tomography (CT) and surgical findings. METHODS: We retrospectively enrolled 209 patients with BAVs who underwent transthoracic echocardiography (TTE) and CT. BAVs were classified as anterior-posterior (BAV-AP) or lateral (BAV-LA) orientation of the cusps and divided according to the presence (raphe+) or absence (raphe-) of a raphe. Ascending aortic dimensions were measured by CT at four levels. RESULTS: BAV-AP was present in 129 patients (61.7%) and raphe+ in 120 (57.4%). Sixty-nine patients (33.0%) had aortic regurgitation (AR), 70 (33.5%) had aortic stenosis (AS), and 58 (27.8%) had combined AS and AR. AR was more common in patients with BAV-AP and raphe+; AS was more common with BAV-LA and raphe-.Annulus/body surface area and tubular portion/body surface area diameters in patients with BAV-AP (17.1 ± 2.3 mm/m(2) and 24.2 ± 5.3 mm/m(2), respectively) and raphe+ (17.3 ± 2.2 mm/m(2) and 24.2 ± 5.5 mm/m(2), respectively) were significantly different from those with BAV-LA (15.8 ± 1.9 mm/m(2) and 26.4 ± 5.5 mm/m(2), respectively) and raphe- (15.7 ± 1.9 mm/m(2) and 26.2 ± 5.4 mm/m(2), respectively). CONCLUSION: The morphological characteristics of BAV might be associated with the type of valvular dysfunction, and degree and location of an ascending aorta dilatation. KEY POINTS: • The BAV-AP type had more frequent aortic regurgitation, raphe, and a larger aortic annulus. • BAV without raphe had more frequent aortic stenosis and mid-ascending aorta dilatation. • CT allows assessment of the morphological characteristics of BAV and associated aortopathy.

Degenerative Calcification of Pericardial Bioprostheses: Comparison of Five Implantation Methods in a Rabbit Model.

BACKGROUND AND AIM OF THE STUDY: The degenerative calcification of bioprosthetic heart valves remains a clinical challenge, especially among young adults and children. Animal models that are based on subcutaneous and intramuscular implantation and are typically used to assess interventions to prevent bioprosthetic heart valve calcification do not reflect actual hemodynamic stress and lack direct blood contact. Thus, the study aim was to investigate bioprosthesis calcification at different implantation sites. METHODS: The calcification degrees of five valve implantation methods, namely subcutaneous, intramuscular and intravenous implantation, and arterial and venous patch angioplasty, were simultaneously investigated in 10 New Zealand White rabbits. RESULTS: Ultrasonography and computed tomography images showed vascular patency to be well maintained in all implanted vessels. Histologically, cellular infiltrates around the implant and within the collagen fibers were only found in the intravenous implantation group, which also had the highest calcium level among the methods. CONCLUSION: The present study was the first to compare the degree of calcification after applying five implantation methods simultaneously in one animal species. The rabbit intravenous implantation model, which involved direct contact with blood factors, is expected to serve as a useful animal model for research into the prevention of bioprosthetic heart valve degeneration.

Relationship between bicuspid aortic valve phenotype, valvular function, and ascending aortic dimensions.

BACKGROUND AND AIM OF THE STUDY: Bicuspid aortic valve (BAV) is known to be associated with aortic valve dysfunction and ascending aorta (AA) dilatation. However, the relationship between BAV morphology and AA dimensions remains unclear. Thus, the study aim was to characterize the aortic valve function and AA dimensions according to the presence of raphe and BAV phenotype. METHODS: A total of 164 patients with BAV who underwent aortic valve surgery between October 2007 and November 2012 was investigated. BAV was classified as either type I (anterior-posterior orientation) or type II (right-left orientation), and subdivided as raphe+ (presence of raphe) and raphe-(no raphe). RESULTS: Type I BAV was present in 103 patients (62.8%), and raphe+ in 100 (61.0%). Patients with raphe+ were typically younger than those with raphe-, and male gender was more predominant (88.0% and 53.1%, respectively, p < 0.05). Aortic regurgitation was more common in patients with type I and raphe+ BAV, and aortic stenosis in patients with type II and raphe- BAV. In patients with raphe+, the diameters of aortic annulus related to the body surface area (BSA) were larger, and the diameters of the tubular portion of AA indexed to BSA were smaller than in patients with raphe- (p < 0.05). CONCLUSION: BAV morphology is helpful for predicting the type of aortic valve dysfunction and the location of AA dilatation.

NF-κB/AP-1-targeted inhibition of macrophage-mediated inflammatory responses by depigmenting compound AP736 derived from natural 1,3-diphenylpropane skeleton.

AP736 was identified as an antimelanogenic drug that can be used for the prevention of melasma, freckles, and dark spots in skin by acting as a suppressor of melanin synthesis and tyrosinase expression. Since macrophage-mediated inflammatory responses are critical for skin health, here we investigated the potential anti-inflammatory activity of AP736. The effects of AP736 on various inflammatory events such as nitric oxide (NO)/prostaglandin (PG) E2 production, inflammatory gene expression, phagocytic uptake, and morphological changes were examined in RAW264.7 cells. AP736 was found to strongly inhibit the production of both NO and PGE2 in lipopolysaccharide- (LPS-) treated RAW264.7 cells. In addition, AP736 strongly inhibited both LPS-induced morphological changes and FITC-dextran-induced phagocytic uptake. Furthermore, AP736 also downregulated the expression of multiple inflammatory genes, such as inducible NO synthase (iNOS), cyclooxygenase- (COX-) 2, and interleukin- (IL-) 1ß in LPS-treated RAW264.7 cells. Transcription factor analysis, including upstream signalling events, revealed that both NF-κB and AP-1 were targeted by AP736 via inhibition of the IKK/IκBα and IRAK1/TAK1 pathways. Therefore, our results strongly suggest that AP736 is a potential anti-inflammatory drug due to its suppression of NF-κB-IKK/IκBα and AP-1-IRAK1/TAK1 signalling, which may make AP736 useful for the treatment of macrophage-mediated skin inflammation.

Entelon150® (Vitis vinifera Seed Extract) Attenuates Degenerative Changes in Intravascular Valve Prostheses in Rabbits.

BACKGROUND AND OBJECTIVES: The therapeutic strategy for inflammation and degenerative calcification is of utmost importance for bioprosthetic heart valve (BHV) implanted patients. The purpose of this study was to compare the anti-inflammatory and anti-calcification effects of Entelon150® (grape seed extract), losartan, and rosuvastatin, in a rabbit model of intravascular BHV leaflet implantation in bovine pericardium. METHODS: A total of 28 rabbits were implanted with BHV leaflet in the external jugular veins. The Entelon150® group was administered 7.7 mg/kg Entelon150® twice daily for 6 weeks after surgery. The losartan and rosuvastatin groups received 5.14 mg/kg and 1 mg/kg, respectively, once per day. The control group received 1 ml of saline once daily. And then, calcium concentration was measured in the implanted BHV, and histological and molecular analyses were performed on the surrounding tissues. RESULTS: The calcium content of the implanted tissue in the Entelon150® group (0.013±0.004 mg/g) was lower than that in the control group (0.066±0.039 mg/g) (p=0.008). The losartan (0.024±0.016 mg/g, p=0.032) and rosuvastatin (0.022±0.011 mg/g, p=0.032) groups had lower calcium content than the control group, and higher tendency than the Entelon150® group. Immunohistochemistry revealed that the expressions of bone morphogenic protein 2 (BMP2), S-100, and angiotensin II type 1 receptor in the Entelon150® group showed lower tendency than those in the control group. The protein expression levels of BMP2 were reduced in the Entelon150® group compared with those in the control group. CONCLUSIONS: Entelon150® exhibited a significant effect, similar to other drugs, in reducing calcification and inflammation in the intravascular bovine pericardium.

Prognosis of Unrepaired Ascending Aorta after the Surgical Replacement of Bicuspid Aortic Valves.

Background: The surgical threshold for bicuspid aortic valve (BAV)-related aortopathy is a matter of debate due to its uncertain etiology and prognosis. This study investigated the prognosis of unrepaired BAV aortopathy in patients undergoing surgical aortic valve replacement (SAVR). Methods: We retrospectively analyzed data from 720 patients (age, 60.8±11.5 years; 246 women) who underwent SAVR for BAV disease without aortic repair between 2005 and 2020 at Asan Medical Center. The clinical endpoints were defined as occurrences of sudden death, aortic dissection or rupture, and elective aortic repair. To estimate postoperative changes in the dimensions of the unrepaired aorta, the individual annual aortic expansion rate was calculated. Multiple linear regression models were used to evaluate the risk of aortic expansion. Results: The mean ascending aortic diameter was 39.5±4.6 mm, and 299 patients (41.5%) had a baseline ascending aorta diameter >40 mm. During 70.0±68.3 months of follow-up, the mean annual aortic expansion rate was 0.39±1.96 mm/yr, no aortic dissection or rupture was observed, and sudden deaths were reported in 12 patients (0.34% per person-year). Linear regression analysis revealed no significant correlation between the baseline ascending aortic diameter and postoperative aortic expansion (R2=0.004, ß=-0.84, p=0.082). Conclusion: In selected patients undergoing SAVR for a BAV (<55 mm), the risk of adverse aortic events was very low. As this observation contradicts current practice guidelines advocating for proactive aortic replacement in dilated ascending aortas measuring >45 mm, the study results need further validation by studies involving larger populations or randomized controlled trials.

Successful liver transplantation following veno-arterial extracorporeal membrane oxygenation in a child with fulminant Wilson disease and severe pulmonary hemorrhage: a case report.

Massive pulmonary hemorrhage and other serious cardiopulmonary diseases in patients with fulminant hepatitis result not only in graft failure but also mortality after LT. ECMO is used to treat children with cardiorespiratory failure refractory to conventional intensive care. We describe a five-yr-old girl with genetically confirmed fulminant Wilson disease and severe pulmonary hemorrhage who underwent successful primary LT following veno-arterial ECMO. To our knowledge, this is the first report of successful primary LT in a patient using veno-arterial ECMO. The present case demonstrates that ECMO, as a bridging modality to LT, may be necessary to manage both massive pulmonary hemorrhage and possible graft loss because of hypoxemia.

SNARE-wedging polyphenols as small molecular botox.

Most cosmetic and therapeutic applications of Clostridium botulinum neurotoxin (BoNT) are related to muscle paralysis caused by the blocking of neurotransmitter release at the neuromuscular junction. BoNT specifically cleaves SNARE proteins at the nerve terminal and impairs neuroexocytosis. Recently, we have shown that several polyphenols inhibit neurotransmitter release from neuronal PC12 cells by interfering with SNARE complex formation. Based on our previous result, we report here that myricetin, delphinidin, and cyanidin indeed paralyze muscle by inhibiting acetylcholine release at the neuromuscular junction. While the effect of myricetin on muscle paralysis was modest compared to BoNT/A, myricetin exhibited a shorter response time than BoNT/A. Intraperitoneally-injected myricetin at an extreme dose of 1000 mg/kg did not induce death of mice, alleviating the safety issue. Thus, these polyphenols might be useful in treating various human hypersecretion diseases for which BoNT/A has been the only option of choice.

Mitral valve replacement using mechanical prostheses in children: early and long-term outcomes.

Compared with mitral repair, mitral valve replacement is an uncommon procedure in children due to associated high mortality and morbidity rates. The present study investigated early and late outcomes after MVR with mechanical prostheses in children at our institution. Between January 1994 and December 2009, 19 children underwent MVR. Mean patient age was 7.6 ± 5.5 years (range 3 months-16 years), and mean body weight was 23.7 ± 15.1 kg (range 5.0-58.1 kg). Mean prosthesis size was 25.8 ± 4.2 mm (range 19-31 mm). There were no operative or late mortalities. Three patients showed decreased left-ventricular function before surgery, and one of them underwent successful heart transplantation due to progressive LV dysfunction at 10 months after MVR. The proportion of patients with freedom from reoperation at 10 years was 94.7 ± 5%. There were no major thromboembolic or bleeding episodes. Although the small number of patients in our study was a limitation, MVR in children was found to result in excellent early and long-term outcomes. It appears that MVR could be considered in children before LV dysfunction develops.

Tetralogy of Fallot with congenital diaphragmatic hernia and left lung hypoplasia: assessment of the adequacy of the peripheral pulmonary vascular growth after hernia repair.

Congenital diaphragmatic hernia is a life-threatening condition frequently associated with various congenital cardiac diseases. In congenital diaphragmatic hernia associated with tetralogy of Fallot, central pulmonary artery size of the affected side may not reflect the capacitance of peripheral pulmonary vascular beds. We report a case of congenital diaphragmatic hernia associated with tetralogy of Fallot, which was repaired after assessing the adequacy of the pulmonary vascular beds by intra-operative pulmonary blood flow study.

Satisfactory outcome with activated clotting time <160 seconds in extracorporeal cardiopulmonary resuscitation.

Patients undergoing cardiopulmonary resuscitation (CPR) prior to extracorporeal membrane oxygenation (ECMO) can have severely altered physiology, including that of the coagulation pathway. This could complicate the extracorporeal cardiopulmonary resuscitation (ECPR) management. We aimed to show that targeting an activated clotting time (ACT) < 160 seconds does not affect the complication rates in these patients. In this single-centered retrospective study, the medical records of 81 adult patients who were on ECMO support from March 2017 to March 2020 were reviewed. We compared the low ACT and conventional ACT groups, which were defined on the basis of the median of the ACT values of the included patients (160 seconds). The primary outcomes included bleeding or thromboembolic events. This study included 32 patients, who were divided into the low (n = 14) and conventional (n = 18) ACT groups. There were 2 cases of gastrointestinal bleeding (P = .183), one of intracranial hemorrhage (P = .437), and one of peripheral skin color change (P = .437) in the low ACT group. There was one case of prolonged bleeding at the cannulation site (P = 1.000) reported in the conventional ACT group. The successful weaning rate differed significantly between the low and conventional ACT groups (92.9% vs 50.0%; P = .019). Maintaining the ACT lower than the conventional ACT in patients requiring ECPR did not show a significant increase in the thromboembolic risk. Therefore, targeting a low ACT should be considered for this particular group of patients.