The first aim of this study was to develop a prothrombin time international normalized ratio (PT INR) prediction model. The second aim was to develop a warfarin maintenance dose decision support system as a precise warfarin dosing platform. Data of 19,719 inpatients from three institutions was analyzed. The PT INR prediction algorithm included dense and recurrent neural networks, and was designed to predict the 5th-day PT INR from data of days 1–4. Data from patients in one hospital (n = 22,314) was used to train the algorithm which was tested with the datasets from the other two hospitals (n = 12,673). The performance of 5th-day PT INR prediction was compared with 2000 predictions made by 10 expert physicians. A generator of individualized warfarin dose-PT INR tables which simulated the repeated administration of varying doses of warfarin was developed based on the prediction model. The algorithm outperformed humans with accuracy terms of within ± 0.3 of the actual value (machine learning algorithm: 10,650/12,673 cases (84.0%), expert physicians: 1647/2000 cases (81.9%), P = 0.014). In the individualized warfarin dose-PT INR tables generated by the algorithm, the 8th-day PT INR predictions were within 0.3 of actual value in 450/842 cases (53.4%). An artificial intelligence-based warfarin dosing algorithm using a recurrent neural network outperformed expert physicians in predicting future PT INRs. An individualized warfarin dose-PT INR table generator which was constructed based on this algorithm was acceptable.

The benefits of concomitant tricuspid annuloplasty (TAP) for non-significant functional tricuspid regurgitation (TR) during mitral valve replacement (MVR) are controversial. We evaluated the long-term outcomes—particularly the long-term tricuspid valve (TV) functional outcomes—of MVR with or without tricuspid ring annuloplasty. From 2004 to 2014, 256 patients (56.4 ± 12.1 years) with trivial or mild functional TR who underwent MVR were enrolled. Eighty-two patients underwent concomitant tricuspid ring annuloplasty (TAP group), and 174 patients did not undergo the TV procedure (nTAP group). Propensity score-matched analysis was performed (n = 72 in each group). The follow-up duration was 77.4 ± 42.4 months. The early clinical outcomes were similar between the 2 groups before and after propensity score matching with an early mortality rate of 3.5% (9 of 256). No patients experienced ring-related complications during follow-up. Eleven (6.3%) patients developed significant TR (≥moderate) in the nTAP group, while no patients developed significant TR in the TAP group. There were no significant differences in overall survival between the 2 groups before or after matching. However, propensity score-matched analysis revealed that the freedom from significant TR aggravation and freedom from TV-related event rates were significantly higher in the TAP group than in the nTAP group (P = 0.047 and P = 0.043, respectively). Patients with untreated trivial or mild functional TR accompanied by mitral valve disease can develop significant TR during follow-up. TV ring annuloplasty can be performed without complications and can be beneficial for patients with trivial or mild functional TR who are undergoing MVR.

The aim of this study was to compare early and late outcomes of tricuspid valve replacement (TVR) and tricuspid valve repair (TVr) for severe tricuspid regurgitation (TR).Methods and Results:From 1994 to 2012, 360 patients (mean age, 58±13 years) with severe TR underwent TVR (n=97, 27%) or TVr (n=263, 73%). Among them, 282 patients (78%) had initial rheumatic etiology, and 307 patients (85%) had preoperative atrial fibrillation. The TVR group had higher total bilirubin, higher baseline central venous pressure, and higher incidence of previous cardiac operation. There was no difference in early mortality (TVR:TVr, 3.1%:3.4%, P=0.877). Ten-year overall survival (TVR:TVr, 72%:70%, P=0.532) and 10-year freedom from cardiac death (TVR:TVr, 76%:77%, P=0.715) were not significantly different between groups. After applying stabilized inverse probability of treatment weighting methods, there were still no significant differences in early mortality (P=0.293), overall survival (P=0.649) or freedom from cardiac death (P=0.870). Higher NYHA functional class, total bilirubin (>2 mg/dL), initial central venous pressure, and cardiopulmonary bypass time were independent predictors of early mortality. Older age, LV dysfunction (EF <40%), and hemoglobin <10 g/dL were independent predictors of late cardiac mortality. Compared with TVr, TVR had acceptable early and late outcomes in patients with severe TR. TVR can be considered as a valid option with acceptable clinical outcomes in patients who are not suitable candidates for TVr.

The objective of this study was to evaluate the effect of treatment with amino compounds and solvents in vivo on calcifications of glutaraldehyde (GA)-fixed pericardium. Groups of bovine pericardium samples were fixed with 0.5% GA. We used urazole and glutamate to neutralize the free aldehyde and some solvents (ethanol with octanol or octanediol) to reduce the phospholipid content in the bovine pericardial tissue. Tensile strength and thermal stability were evaluated before implantation. Twelve weeks after rat subdermal implantation, the pericardial samples were harvested from eight juvenile rats. Urazole [calcium (Ca²⁺): 11.86±2.85 μg/mg; inorganic phosphorus (IP): 32.59±7.73 μg/mg] or glutamate (Ca²⁺: 7.95±1.21 μg/mg; IP: 21.76±3.48 μg/mg) alone significantly decreased the Ca²⁺ and IP concentrations (without any anti-calcification treatment, Ca²⁺: 277.85±17.51 μg/mg; IP: 147.07±8.32 μg/mg), but when used with organic solvents, the Ca²⁺ and IP concentrations were the lowest (Ca²⁺: 0.05±0.04 μg/mg; IP: 3.36±0.61 μg/mg). After anti-calcification treatment, the calcifications in microscopic images were dramatically decreased. Anti-calcification treatment with glutamate, urazole, and solvents did not worsen the physical properties of bovine pericardium, and significantly prevented in vivo calcifications compared to GA fixation only. There should be additional studies done to understand the other mechanism underlying xenograft tissue calcification.

We evaluated the outcomes of patients who underwent extracardiac Fontan circulation procedures (ECFP) and received 16-mm polytetrafluoroethylene conduits. From June 1997 to May 2015, among the 408 patients who underwent ECFP, 66 patients (Group S) also received 16-mm polytetrafluoroethylene conduits. To compare this patient cohort with similarly sized patients who received larger conduits, a matched cohort (66 patients, Group L) was selected according to age and body weight. The mean age, body weight and Nakata index at ECFP in Groups S and L were 2.9 ± 1.2 and 3.1 ± 1.2 years (P = 0.243), 13.0 ± 2.4 and 13.0 ± 2.3 kg (P = 0.101), 175.3 ± 59.0 and 236.1 ± 75.1 mm²/m² (P = 0.005), respectively. The mean follow-up periods for Groups S and L were 7.8 ± 6.0 and 9.1 ± 4.9 years (P = 0.150), respectively. The conduit size of Group L was 19.2 ± 1.4 mm (P < 0.001). There was no significant difference in mortality between the groups (P = 0.109). The freedom from reoperation was 94.0 ± 3.4% in Group S and 79.3 ± 5.7% in Group L after 10 years (P = 0.070). Late-occurring morbidities included protein-losing enteropathy (2 in Group S, 4 in Group L; P = 0.491) and thromboembolism (0 in Group S, 4 in Group L; P = 0.206). There was a significant difference in conduit-related events between the groups (1 in Group S, 5 in Group L; P = 0.031). In a paired cohort from the 2 groups including patients who were followed-up for more than 10 years (15 patients from each group), the body mass index was 51.0 ± 33.2% in Group S and 30.3 ± 34.2% in Group L. The decreases in the conduit cross-sectional areas for the paired patients in Group S (n = 20) and Group L (n = 20) were 14.9 ± 19.7% and 24.5 ± 15.5% (P = 0.076), respectively. Coarse liver parenchyma was detected in 9 of 23 (39.1%) patients from Group S and in 7 of 18 (38.8%) patients from Group L upon ultrasonography. The 16-mm polytetrafluoroethylene conduit for ECFP showed acceptable outcomes and good haemodynamic status in small-sized patients. According to our results, small patients do not require large conduits to accommodate their growth potential.