Diagnosis of Atrial Fibrillation Using Machine Learning With Wearable Devices After Cardiac Surgery: Algorithm Development Study.

BACKGROUND: Some attempts have been made to detect atrial fibrillation (AF) with a wearable device equipped with photoelectric volumetric pulse wave technology, and it is expected to be applied under real clinical conditions. OBJECTIVE: This study is the second part of a 2-phase study aimed at developing a method for immediate detection of paroxysmal AF, using a wearable device with built-in photoplethysmography (PPG). The objective of this study is to develop an algorithm to immediately diagnose AF by an Apple Watch equipped with a PPG sensor that is worn by patients undergoing cardiac surgery and to use machine learning on the pulse data output from the device. METHODS: A total of 80 patients who underwent cardiac surgery at a single institution between June 2020 and March 2021 were monitored for postoperative AF, using a telemetry-monitored electrocardiogram (ECG) and an Apple Watch. AF was diagnosed by qualified physicians from telemetry-monitored ECGs and 12-lead ECGs; a diagnostic algorithm was developed using machine learning on the pulse rate data output from the Apple Watch. RESULTS: One of the 80 patients was excluded from the analysis due to redness caused by wearing the Apple Watch. Of 79 patients, 27 (34.2%) developed AF, and 199 events of AF including brief AF were observed. Of them, 18 events of AF lasting longer than 1 hour were observed, and cross-correlation analysis showed that pulse rate measured by Apple Watch was strongly correlated (cross-correlation functions [CCF]: 0.6-0.8) with 8 events and very strongly correlated (CCF>0.8) with 3 events. The diagnostic accuracy by machine learning was 0.9416 (sensitivity 0.909 and specificity 0.838 at the point closest to the top left) for the area under the receiver operating characteristic curve. CONCLUSIONS: We were able to safely monitor pulse rate in patients who wore an Apple Watch after cardiac surgery. Although the pulse rate measured by the PPG sensor does not follow the heart rate recorded by telemetry-monitored ECGs in some parts, which may reduce the accuracy of AF diagnosis by machine learning, we have shown the possibility of clinical application of using only the pulse rate collected by the PPG sensor for the early detection of AF.

A case of clinically amyopathic dermatomyositis that was refractory to intensive immunosuppressive therapy including tofacitinib, but successfully treated with plasma exchange therapy.

Clinically amyopathic dermatomyositis (CADM) patients often develop rapidly progressive interstitial lung disease (RP-ILD). A high level of anti-melanoma differentiation-associated gene 5 antibodies (anti-MDA5 Ab) before treatment is associated with RP-ILD development, a poor treatment response, and poor survival. The prognosis of CADM patients remains poor due to ILD even with combined intensive immunosuppressive therapy. Recently, several additional therapies, including tofacitinib (TOF) and plasma exchange (PE) therapy, have been reported to be effective. We herein report a case of CADM-ILD with a high level of anti-MDA5 Ab that was refractory to combined intensive immunosuppressive therapy including TOF, but successfully treated with PE. The following are possible reasons why TOF was ineffective: (1) cytokines that were not suppressed by TOF played an important role in RP-ILD; (2) TOF was administered later than previously reported; and (3) TOF did not suppress pathological substances such as antibodies. On the other hand, PE removes cytokines and various pathological substances. Therefore, PE may be a more reasonable additional therapy for intractable CADM-ILD.

Usefulness of tissue inhibitor of metalloproteinase 1 as a predictor of sustained remission in patients with antineutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: We previously identified tissue inhibitor of metalloproteinase 1 (TIMP-1) as a biomarker of disease activity that distinguished mildly or highly active antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) from remission 6 months after the initiation of remission-induction therapy. In the present study, we investigated whether TIMP-1 is clinically useful as a predictor of relapse and sustained remission in AAV patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) during maintenance therapy. METHODS: The relationship between serum TIMP-1 levels and clinical outcomes in AAV patients receiving maintenance therapy was assessed using the follow-up data of a Japanese large-cohort study (the RemIT-JAV-RPGN study) and data collected from AAV patients on maintenance therapy in our hospital (the MAAV-EU study). RESULTS: In the RemIT-JAV RPGN study, serum levels of TIMP-1 were significantly higher in mildly active AAV patients with MPA and GPA 6 months after the initiation of remission-induction therapy than in patients in remission. Regarding maintenance therapy, elevated levels of TIMP-1 in patients in remission were associated with relapse and/or difficulty reducing the glucocorticoid dosage after 6 to 12 months. In the MAAV-EU study, serum levels of TIMP-1 were elevated in relapsed patients 6 months before relapse, earlier than the increase in serum levels of CRP. Analyses of both studies revealed that approximately 30% of patients in remission with a serum TIMP-1 level ≥ 150 ng/mL relapsed after 6 to 12 months, while the majority of patients with a TIMP-1 level < 150 ng/mL sustained remission for at least 12 months. CONCLUSION: We herein demonstrated that TIMP-1 is more useful as a predictive biomarker of sustained remission than as a predictor of relapse in maintenance therapy for AAV. TIMP-1 levels < 150 ng/mL are important for the long-term maintenance of remission and may be an indicator for the tapering or cessation of treatment.

Giant Cell Arteritis Presenting with Ptosis and Diplopia.

Giant cell arteritis (GCA) is vasculitis of large-sized vessels that can lead to vision loss. We herein report a rare case of GCA accompanied by ptosis and diplopia as early symptoms, which were caused by third nerve palsy. A 78-year-old man presented with fever, right temporal headache, right eyelid ptosis, and diplopia. GCA was confirmed by a temporal artery biopsy. The symptoms disappeared after a slight delay following the administration of prednisolone. Unlike vision loss, ptosis and diplopia are considered to be reversible and responsive to treatment. GCA should not be ruled out if patients exhibit these ophthalmic symptoms.

Safety and efficacy of a simple cardiotomy suction system as a blood salvage procedure during off-pump coronary artery bypass surgery.

The ideal blood-salvaging strategies for off-pump coronary artery bypass graft procedures have not been determined. We developed a new blood-salvaging system that uses a cardiotomy suction. The purpose of this study was to examine the efficacy of this novel method. This was a retrospective study involving 50 consecutive patients undergoing off-pump coronary artery bypass grafting. In 25 patients, a simple cardiotomy suction system was used (cardiotomy suction group). These individuals were compared with 25 historical cohorts who were treating with the conventional cell saver system (cell saver group). There was no in-hospital mortality in either group. In the cell saver group, there was one major complication (stroke) and two minor complications (saphenous vein graft occlusion, superficial wound infection). In the cardiotomy suction group, there was one minor complication (subclinical pulmonary emboli). The cardiotomy suction group received significantly fewer transfused RBC (cardiotomy: 0.56 ± 1.4 units vs. cell saver: 2.46 ± 3.3 units, p = 0.005). The serum total protein and albumin levels were significantly higher in the cardiotomy group. Our newly developed simple cardiotomy suction system, when compared with the conventional cell saver system, produced similar clinical results and attenuated postoperative hemodilution. Our system may emerge as a preferable alternative for blood salvage during off-pump coronary artery bypass grafting.

Radiation therapy for recurrent cardiac undifferentiated pleomorphic sarcoma after three operations.

We report the case of a 57-year-old female suffering from recurrent malignant undifferentiated pleomorphic sarcoma of the left atrium. Metastasis to the posterior mediastinum was detected upon first presentation. Incomplete resections were carried out twice before mitral valve replacement was finally performed. The tumor recurred 16 months later and was treated with radiation therapy, which has proved to be effective in bringing about tumor regression for 2 years, to date. The patient has survived for 7 years since the first surgery.

Thoracoabdominal aortic repair in a patient with Ehlers-Danlos syndrome.

Type IV Ehlers-Danlos syndrome is a life-threatening inherited disorder of connective tissue associated with multiple aneurysm formation. Thoracoabdominal aortic repair in these patients has rarely been performed. We report the case of a 13-year-old patient with Ehlers-Danlos syndrome who had multiple aortic operations from the ascending aorta to the thoracoabdominal aorta.

Development of a method to measure DNA methylation levels by using methyl CpG-binding protein and luciferase-fused zinc finger protein.

DNA methylation, which is an important epigenetic event for transcriptional regulation, is regarded as a biomarker for cancer. A rapid and sensitive method for measuring DNA methylation levels in target genomic regions may enable early diagnosis of cancer. To detect DNA methylation levels conveniently, we developed a detection system for DNA methylation, designated as methylated DNA precipitation combined luciferase-fused zinc finger assay (MELZA), which uses methyl CpG-binding domain (MBD) and luciferase-fused zinc finger protein. This system comprises the following 3 steps: (1) MBD-based methylated DNA precipitation, (2) PCR amplification of the target genomic region, and (3) detection of the PCR product quantity by using luciferase-fused zinc finger protein. Using this system, we have accurately measured methylation levels of the androgen receptor gene promoter region in LNCaP, PC3, Du145, and whole blood cells. This system does not require bisulfite treatment, and all the steps can be automated. Therefore, it might be useful for measuring DNA methylation levels in clinical cancer diagnoses.

Roles of copper chaperone for superoxide dismutase 1 and metallothionein in copper homeostasis.

Copper chaperone for SOD1 (CCS) specifically delivers copper (Cu) to copper, zinc superoxide dismutase (SOD1) in cytoplasm of mammalian cells. In the present study, small interfering RNA (siRNA) targeting CCS was introduced into metallothionein-knockout mouse fibroblasts (MT-KO cells) and their wild type cells (MT-WT cells) to reveal the interactive role of CCS with other Cu-regulating proteins, in particular, MT. CCS knockdown significantly decreased Ctr1, a Cu influx transporter, mRNA expression. On the other hand, Atp7a, a Cu efflux transporter, mRNA expression was increased 3.0 and 2.5 times higher than those of the control in MT-WT and MT-KO cells. These responses of Cu-regulating genes to the CCS knockdown reflected the presence of excess Cu in the cells. To evaluate the Atp7a function in the Cu-replete cells, siRNA of Atp7a and the other Cu transporter, Atp7b were introduced into MT-WT and MT-KO cells. The Atp7a knockdown significantly increased the intracellular Cu concentration, whereas the Atp7b knockdown had no affect. Although two MT isoforms were induced by the CCS knockdown in MT-WT cells, the expression and activity of SOD1 were maintained in both MT-WT and MT-KO cells even when CCS protein expression was reduced to 0.30-0.35 of control. This suggests that the amount of CCS protein exceeds that required to supply Cu to SOD1 in the cells. Further, the CCS knockdown induces Cu accumulation in cells, however, the Cu accumulation is ameliorated by the MT induction, the decrease of Ctr1 expression and the increase of Atp7a expression to maintain Cu homeostasis.

Roles of COMM-domain-containing 1 in stability and recruitment of the copper-transporting ATPase in a mouse hepatoma cell line.

A novel function of COMMD1 {COMM [copper metabolism MURR1 (mouse U2af1-rs1 region 1)]-domain-containing 1}, a protein relevant to canine copper toxicosis, was examined in the mouse hepatoma cell line Hepa 1-6 with multi-disciplinary techniques consisting of molecular and cellular biological techniques, speciation and elemental imaging. To clarify the function of COMMD1, COMMD1-knockdown was accomplished by introducing siRNA (small interfering RNA) into the cells. Although COMMD1-knockdown did not affect copper incorporation, it inhibited copper excretion, resulting in copper accumulation, which predominantly existed in the form bound to MT (metallothionein). It is known that the liver copper transporter Atp7b (ATP-dependent copper transporter 7beta), localizes on the trans-Golgi network membrane under basal copper conditions and translocates to cytoplasmic vesicles to excrete copper when its concentration exceeds a certain threshold, with the vesicles dispersing in the periphery of the cell. COMMD1-knockdown reduced the expression of Atp7b, and abolished the relocation of Atp7b back from the periphery to the trans-Golgi network membrane when the copper concentration was reduced by treatment with a Cu(I) chelator. The same phenomena were observed during COMMD1-knockdown when another Atp7b substrate, cis-diamminedichloroplatinum, and its sequestrator, glutathione ethylester, were applied. These results suggest that COMMD1 maintains the amount of Atp7b and facilitates recruitment of Atp7b from cytoplasmic vesicles to the trans-Golgi network membrane, i.e. COMMD1 is required to shuttle Atp7b when the intracellular copper level returns below the threshold.