乾 友彦

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.

症例は48歳男性。解離性大動脈瘤(DeBakey III B型)に対し25歳時に下行大動脈置換術、27歳時に上行大動脈瘤に対し上行大動脈+部分弓部大動脈置換術、28歳時に残存解離による胸腹部大動脈瘤に対し胸腹部大動脈置換術を施行され外来で経過観察されていた。3回目の手術時に腹腔動脈・上腸間膜動脈・右腎動脈がVisceral aortic patch(VAP)を用いて再建されており、同部の残存している自家大動脈壁に瘤化(最大径70mm×61mm)を認めたため手術の方針となった。2回の左開胸手術後であったため2期的にhybrid aortic repairを施行する方針とし1回目にreno-visceral debranching手術、2回目にステントグラフト内挿術を行い、瘤の空置に成功した。(著者抄録)

Left ventricular assist device (LVAD) is an established therapy for patients with severe heart failure. Because the incidence of cardiotoxicity owing to anticancer agents is low, it is difficult to predict the recovery prospects when the cause of heart failure is due to anticancer agents. In this context, cancer patients who present with severe symptoms of heart failure and who fail medical therapy for heart failure may pose a dilemma, especially in countries such as Japan where implantable LVADs are not approved for purposes other than bridging to transplant. Recently, we encountered a 32-year-old woman with chemotherapy-related cardiomyopathy that developed after anticancer treatment using trastuzumab and anthracycline. LVAD therapy was the only option to save the young woman. The patient received an extracorporeal LVAD, her cardiac function gradually recovered while on support, and the device was successfully removed.

Pulmonary embolectomy is an effective treatment of acute pulmonary embolism (APE) but not for chronic pulmonary thromboembolism. We described surgical experience of two patients with APE in preexistent unidentified chronic pulmonary thromboembolism. One patient who presented with severe hypoxia but stable hemodynamics underwent successful pulmonary endarterectomy for proximal organized thrombus instead of pulmonary embolectomy. The other patient who required extracorporeal membrane oxygenation for severe hypoxia developed right heart failure because of residual distal organized thrombus after pulmonary embolectomy. Clinical and radiographical presentation of APE in chronic pulmonary thromboembolism mimics APE, and thus, candidates of pulmonary embolectomy should be carefully selected.

BACKGROUND: Wearable devices with photoplethysmography (PPG) technology can be useful for detecting paroxysmal atrial fibrillation (AF), which often goes uncaptured despite being a leading cause of stroke. OBJECTIVE: This study is the first part of a 2-phase study that aimed at developing a method for immediate detection of paroxysmal AF using PPG-integrated wearable devices. In this study, the diagnostic performance of 2 major smart watches, Apple Watch Series 3 and Fitbit (FBT) Charge HR Wireless Activity Wristband, each equipped with a PPG sensor, was compared, and the pulse rate data outputted from those devices were analyzed for precision and accuracy in reference to the heart rate data from electrocardiography (ECG) during AF. METHODS: A total of 40 subjects from patients who underwent cardiac surgery at a single center between September 2017 and March 2018 were monitored for postoperative AF using telemetric ECG and PPG devices. AF was diagnosed using a 12-lead ECG by qualified physicians. Each subject was given a pair of smart watches, Apple Watch and FBT, for simultaneous pulse rate monitoring. The heart rate of all subjects was also recorded on the telemetry system. Time series pulse rate trends and heart rate trends were created and analyzed for trend pattern similarities. Those trend data were then used to determine the accuracy of PPG-based pulse rate measurements in reference to ECG-based heart rate measurements during AF. RESULTS: Of the 20 AF events in group FBT, 6 (30%) showed a moderate or higher correlation (cross-correlation function>0.40) between pulse rate trend patterns and heart rate trend patterns. Of the 16 AF events in group Apple Watch (workout [W] mode), 12 (75%) showed a moderate or higher correlation between the 2 trend patterns. Linear regression analyses also showed a significant correlation between the pulse rates and the heart rates during AF in the subjects with Apple Watch. This correlation was not observed with FBT. The regression formula for Apple Watch W mode and FBT was X=14.203 + 0.841Y and X=58.225 + 0.228Y, respectively (where X denotes the mean of all average pulse rates during AF and Y denotes the mean of all corresponding average heart rates during AF), and the coefficient of determination (R2) was 0.685 and 0.057, respectively (P<.001 and .29, respectively). CONCLUSIONS: In this validation study, the detection precision of AF and measurement accuracy during AF were both better with Apple Watch W mode than with FBT.

The purpose of this study is to compare the late outcome of aortic valve replacement with or without preoperative coronary artery disease, and with or without coronary artery bypass. Between 2014 and 2015, 291 patients underwent aortic valve replacement. Average follow-up term was 2.5 ± 2.2 years. The retrospective comparative study was performed between the patients with (n = 115) or without (n = 176) preoperative coronary artery disease (Study 1) and with (n = 93) or without (n = 198) coronary artery bypass grafting (Study 2). Study 1: male patients were more, and diabetes was more in the patients with coronary artery disease. Long-term survival rate was significantly low in the patients with coronary artery disease (p = 0.0002 by log rank test). Freedom from repeat coronary revascularization rate was lower in the patients with coronary artery disease (p = 0.02 by log rank test). Study 2: operation time (419 ± 130 vs 290 ± 101; p = 0.0001) was longer in the patients with coronary artery bypass grafting. Improvement of ejection fraction at follow-up was more in the patients with coronary artery bypass(114 ± 43 vs 104 ± 26%; p = 0.03). Long-term survival rate and freedom from major adverse cardiac event rater were not different with or without coronary artery bypass grafting (p = 0.26 and p = 0.59, respectively, by log rank test). Although prevalence of coronary artery disease inversely affected the long-term outcome of the aortic valve replacement, simultaneous coronary artery bypass did not. Aggressive simultaneous coronary revascularization would be important to improve the long-term outcome of aortic valve replacement.