Background: In Japan, oxygen is commonly administered during the acute phase of myocardial infarction (MI) to patients without oxygen saturation monitoring. In this study we assessed the effects of supplemental oxygen therapy, compared with ambient air, on mortality and cardiac events by synthesizing evidence from randomized controlled trials (RCTs) of patients with suspected or confirmed acute MI.

Methods and Results: PubMed was systematically searched for full-text RCTs published in English before June 21, 2020. Two reviewers independently screened the search results and appraised the risk of bias. The estimates for each outcome were pooled using a random-effects model. In all, 2,086 studies retrieved from PubMed were screened. Finally, 7,322 patients from 9 studies derived from 4 RCTs were analyzed. In-hospital mortality in the oxygen and ambient air groups was 1.8% and 1.6%, respectively (risk ratio [RR] 0.90; 95% confidence interval [CI] 0.38–2.10]); 0.8% and 0.5% of patients, respectively, experienced recurrent MI (RR 0.44; 95% CI 0.12–1.54), 1.5% and 1.6% of patients, respectively, experienced cardiac shock (RR 1.10; 95% CI 0.77–1.59]), and 2.4% and 2.0% of patients, respectively, experienced cardiac arrest (RR 0.91; 95% CI 0.43–1.94).

Conclusions: Routine supplemental oxygen administration may not be beneficial or harmful, and high-flow oxygen may be unnecessary in normoxic patients in the acute phase of MI.

Background: Acute coronary syndrome (ACS) patients with solid lesions often require predilatation before stenting. Predilatation with high pressure may increase the risk of distal embolism, whereas direct stenting increases the risk of stent underexpansion. We recently reported that, in severely calcified lesions, using a cutting balloon (CB) can provide greater acute gain compared with other scoring balloons. Therefore, we hypothesized that predilatation with CB may reduce the incidence of distal embolism in ACS patients with solid lesions.

Methods and Results: This study retrospectively analyzed data for 175 ACS patients who required predilatation, either with a conventional balloon (n=136) or CB (n=39). The occurrence of distal embolism was significantly lower in the CB than conventional balloon group (10.3% vs 32.4%, respectively; P=0.007). Multivariate analysis showed that the occurrence of distal embolism was positively associated with Thrombolysis in Myocardial Infarction (TIMI) grade and the presence of attenuated plaque, but negatively associated with the use of a CB. To support this clinical observation, we compared thrombus dispersal using a CB and non-compliant balloon in an ex vivo experimental model using a pseudo-thrombus. In this model, pseudo-thrombus dispersal was significantly smaller when a CB rather than non-compliant balloon was used (1.8±1.0% vs 2.6±1.2%, respectively; n=20, for each; P=0.002).

Conclusions: In ACS patients with solid lesions that require predilatation, predilatation with a CB may reduce the incidence of distal embolism.

Background: Although reductions in hospitalizations for myocardial infarction and heart failure have been reported during the period of COVID-19 pandemic restrictions, it is unclear how the overall number of hospitalizations for cardiovascular disease (CVD) treatment changed in the early stages of the pandemic.

Methods and Results: We analyzed the records of 574 certified hospitals affiliated with the Japanese Circulation Society and retrieved data from April 2015 to March 2020. Records were obtained from the nationwide Japanese Registry of All Cardiac and Vascular Diseases–Diagnosis Procedure Combination database. A quasi-Poisson regression model was used to estimate the number of hospitalizations for CVD treatment. Between January and March 2020, when the number of COVID-19 cases was relatively low in Japan, the actual/estimated number of hospitalizations for acute CVD was 18,233/21,634 (84.3%), whereas the actual/estimated number of scheduled hospitalizations was 16,921/19,066 (88.7%). The number of hospitalizations for acute heart failure and scheduled hospitalizations for valvular disease and aortic aneurysm were 81.1%, 84.6%, and 83.8% of the estimated values, respectively. A subanalysis that considered only facilities without hospitalization restrictions did not alter the results for these diseases.

Conclusions: The spread of COVID-19 was associated with a decreased number of hospitalizations for CVD in Japan, even in the early stages of the pandemic.

Background: The correlation between the Japanese version of high bleeding risk (J-HBR) criteria and the Predicting Bleeding Complications in Patients Undergoing Stent Implantation and Subsequent Dual Antiplatelet Therapy (PRECISE-DAPT) score is unknown, as is the relationship of both risk scores with ischemic events.

Methods and Results: This study enrolled 842 patients who underwent percutaneous coronary intervention (PCI) between January 2016 and December 2020. The 2 bleeding risk scores at the time of PCI and the subsequent risk of bleeding and ischemic events over a 1-year follow-up were examined. The J-HBR score was significantly correlated with the PRECISE-DAPT score (r=0.731, P<0.001). However, 1 year after PCI, the J-HBR was not significantly associated with the incidence of major bleeding and ischemic events (log-rank, P=0.058 and P=0.351, respectively), whereas the PRECISE-DAPT score predicted both the incidence of major bleeding and ischemic events (log-rank, P=0.006 and P=0.019, respectively). According to receiver operating characteristic curve analysis, a J-HBR score ≥1.5 was significantly associated with a higher cumulative incidence of major bleeding, but not ischemic events (log-rank, P=0.004 and P=0.513, respectively).

Conclusions: The J-HBR score is highly correlated with the PRECISE-DAPT score. A J-HBR score ≥1.5 can identify high bleeding risk patients without an increased risk of ischemic events.

Background: Rivaroxaban, a direct oral anticoagulant, is used as first-line treatment to prevent venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE). However, the frequency of rivaroxaban discontinuation and the subsequent clinical outcomes remain unclear.

Methods and Results: The study was a subanalysis of the prospective, multicenter, observational J’xactly study, conducted in Japan, and included patients who underwent anticoagulant discontinuation without major bleeding and recurrent VTE. The modified intention-to-treat population (n=1,016) included 579 patients (57%) who underwent anticoagulant discontinuation during a mean follow-up period of 20.2 months (mean [±SD] anticoagulation period 6.9±6.2 months). Patients were divided into 3 groups: those with active cancer, those without active cancer and a transient risk factor for VTE, and those without active cancer or a transient risk factor and/or with previous VTE (unprovoked group). After discontinuation, VTE recurrence occurred in 4.1% of patients, with an annual incidence of 4.6%/year and an increased tendency in the unprovoked group; major bleeding occurred in 8 patients (1.4%; annual incidence 1.1%/year), of whom half were in the cancer group.

Conclusions: This analysis of a real-world observational study provides data on VTE recurrence after rivaroxaban discontinuation, which will facilitate anticoagulant discontinuation according to individual risk-benefit considerations.

Background: Lower extremity artery disease (LEAD) is an arterial occlusive disease characterized by an insufficient blood supply to the lower limb arteries. The H₂FPEF score, comprising Heavy, Hypertensive, atrial Fibrillation, Pulmonary hypertension, Elder, and Filling pressure, has been developed to identify patients at high risk of heart failure (HF) with preserved ejection fraction. This study assessed the impact of modified H₂FPEF scores on chronic limb-threatening ischemia (CLTI) in patients with LEAD.

Methods and Results: This study was a prospective observational study. Because the definition of obesity differs by race, we calculated the modified H₂FPEF score using a body mass index >25 kg/m²to define obesity in 293 patients with LEAD who underwent first endovascular therapy. The primary endpoints were newly developed and recurrent CLTI. The secondary endpoint was a composite of events, including mortality and rehospitalization due to worsening HF and/or CLTI. The modified H₂FPEF score increased significantly with advancing Fontaine classes. Multivariate Cox proportional hazard analysis revealed that the modified H₂FPEF score was an independent predictor of newly developed and recurrent CLTI and composite events. The net reclassification index and integrated discrimination improvement were significantly improved by adding the modified H₂FPEF score to the basic predictors.

Conclusions: The modified H₂FPEF score was associated with LEAD severity and future CLTI development, suggesting that it could be a feasible marker for patients with LEAD.