A model-based pharmacokinetic assessment of drug-drug interaction between tacrolimus and nirmatrelvir/ritonavir in a kidney transplant patient with COVID-19.

We experienced a patient with a remarkable and prolonged increase in tacrolimus blood concentrations when nirmatrelvir/ritonavir was concomitantly used. The inhibitory intensity and duration of nirmatrelvir/ritonavir on tacrolimus pharmacokinetics were examined using a model-based analysis. A renal transplant patient taking oral tacrolimus continuously was treated with nirmatrelvir/ritonavir for 5 days. The baseline tacrolimus trough blood concentration was 4.2 ng/mL. Tacrolimus was discontinued on Day 6 after the concomitant administration of nirmatrelvir/ritonavir, and the trough concentration increased to 96.4 ng/mL on Day 7. The model-based analysis showed that tacrolimus clearance decreased to 35% and bioavailability increased by 18.7-fold after the coadministration of nirmatrelvir/ritonavir, compared with before the coadministration. Therefore, nirmatrelvir/ritonavir drastically decreased both the apparent clearance and apparent volume of distribution. Simulated tacrolimus concentrations could be best fitted to the observed concentrations when the inhibitory effects of nirmatrelvir/ritonavir were modeled to disappear over about 10 days by first-order elimination. In conclusion, nirmatrelvir/ritonavir greatly increases tacrolimus concentrations by not only reducing clearance, but also increasing bioavailability. Interactions between nirmatrelvir/ritonavir and low-bioavailability drugs which are substrates for CYP3A and P-glycoprotein, such as tacrolimus, are harmful, and concomitant use of these medicines should be avoided.

Assessment of satisfaction with antiretroviral drugs and the need for long-acting injectable medicines among people living with HIV in Japan and its associated factors: a prospective multicenter cross-sectional observational study.

BACKGROUND: Long-acting injectable formulations for HIV infection have been approved and are now available in Japan. Although not currently recommended as first-line drugs in Japanese or overseas guidelines, use of such formulations may increase, in accordance with patient conditions and preference. We determine the level of satisfaction with current anti-HIV drugs and analyzed the preferences of patients who favor long-acting injectable drugs based on their satisfaction level with the present anti-HIV drugs. METHODS: People living with HIV (PLWH) who had received antiretroviral therapy (ART) for at least one month and consented to the study between 1 April and 31 December 2021 were included in a survey conducted using a self-administered questionnaire. The content of the survey included satisfaction with seven items (tablet size, ease and feeling when taking the medicine, color, taste, portability, daily oral therapy, and co-payment) related to the anti-HIV drugs they were taking and their need for future drugs (dosage form, frequency of dosing, long-acting injectable, etc.). In addition, factors related to the need for long-acting injectable medications were analyzed with regard to the relationship with satisfaction with anti-HIV drugs. RESULTS: Overall, 667 patients available for analysis were included in this study. Satisfaction with anti-HIV drugs was highest with regard to "co-payment" and lowest with "daily oral therapy". Regarding the need for long-acting injectable medications, logistic regression analysis indicated that tablet size and daily oral therapy were significant predictors of patient preference for a once-every-eight-weeks intramuscular formulation in terms of their requirement for long-acting injectable medications (tablet size, OR = 2.14, 95%CI 1.030-4.430, p = 0.042; and daily oral therapy, OR = 1.75, 95%CI 1.010-3.030, p = 0.044). CONCLUSIONS: Patients currently receiving anti-HIV drugs who express dissatisfaction with tablet size and daily oral therapy may prefer a long-acting injectable formulation, taking into consideration patient age, employment status, ART history, frequency of daily dosage and concomitant medications other than ART.

Public assistance in patients with acute heart failure: a report from the KCHF registry.

AIMS: There is a scarcity of data on the post-discharge prognosis in acute heart failure (AHF) patients with a low-income but receiving public assistance. The study sought to evaluate the differences in the clinical characteristics and outcomes between AHF patients receiving public assistance and those not receiving public assistance. METHODS AND RESULTS: The Kyoto Congestive Heart Failure registry was a physician-initiated, prospective, observational, multicentre cohort study enrolling 4056 consecutive patients who were hospitalized due to AHF for the first time between October 2014 and March 2016. The present study population consisted of 3728 patients who were discharged alive from the index AHF hospitalization. We divided the patients into two groups, those receiving public assistance and those not receiving public assistance. After assessing the proportional hazard assumption of public assistance as a variable, we constructed multivariable Cox proportional hazard models to estimate the risk of the public assistance group relative to the no public assistance group. There were 218 patients (5.8%) receiving public assistance and 3510 (94%) not receiving public assistance. Patients in the public assistance group were younger, more frequently had chronic coronary artery disease, previous heart failure hospitalizations, current smoking, poor medical adherence, living alone, no occupation, and a lower left ventricular ejection fraction than those in the no public assistance group. During a median follow-up of 470 days, the cumulative 1 year incidences of all-cause death and heart failure hospitalizations after discharge did not differ between the public assistance group and no public assistance group (13.3% vs. 17.4%, P = 0.10, and 28.3% vs. 23.8%, P = 0.25, respectively). After adjusting for the confounders, the risk of the public assistance group relative to the no public assistance group remained insignificant for all-cause death [hazard ratio (HR), 0.97; 95% confidence interval (CI), 0.69-1.32; P = 0.84]. Even after taking into account the competing risk of all-cause death, the adjusted risk within 180 days in the public assistance group relative to the no public assistance group remained insignificant for heart failure hospitalizations (HR, 0.93; 95% CI, 0.64-1.34; P = 0.69), while the adjusted risk beyond 180 days was significant (HR, 1.56; 95% CI, 1.07-2.29; P = 0.02). CONCLUSIONS: The AHF patients receiving public assistance as compared with those not receiving public assistance had no significant excess risk for all-cause death at 1 year after discharge or a heart failure hospitalization within 180 days after discharge, while they did have a significant excess risk for heart failure hospitalizations beyond 180 days after discharge. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT02334891 (NCT02334891) and https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000017241 (UMIN000015238).

Clinical characteristics and outcomes of patients with venous thromboembolism according to diagnosis on weekends versus on weekdays.

There are uncertainties on the influence of the days of diagnosis in a week (weekends versus weekdays) on clinical outcomes in patients with acute venous thromboembolism (VTE), including pulmonary embolism (PE) and deep vein thrombosis (DVT). The COMMAND VTE registry is a multicenter cohort study enrolling 3027 consecutive patients with acute symptomatic VTE. The current study population consisted of 337 patients diagnosed on weekends and 2690 patients diagnosed on weekdays. We compared the clinical characteristics, management strategies and 30-day outcomes between the 2 groups. The patients diagnosed on weekends more often presented with PE (72% vs. 55%, P < 0.001), and with more severe hemodynamic condition for PE patients. The patients diagnosed on weekends more often received initial parenteral anticoagulation therapy and thrombolysis than those diagnosed on weekdays. The cumulative 30-day incidence of all-cause death was not significantly different between the two groups among PE patients (diagnosis on weekends: 6.2% vs. diagnosis on weekdays: 6.5%, P = 0.87), as well as among DVT patients (0.0% vs. 1.5%, P = 0.24). The most frequent cause of deaths was fatal PE in both groups among PE patients. The risks for recurrent VTE and major bleeding at 30-day were not significantly different between the 2 groups among PE patients, nor among DVT only patients. In conclusion, the VTE patients diagnosed on weekends presented more often with PE, and with more severe condition for PE patients. Nevertheless, the risk for 30-day mortality was not significantly different between patients diagnosed on weekends and on weekdays.

Efficacy of pharmacists' assessment and intervention based on Screening Tool for Older Persons' Appropriate Prescriptions for Japanese compared with Screening Tool of Older Persons' potentially inappropriate Prescriptions criteria version 2 in older patients with cardiovascular disease.

AIM: This study aimed to evaluate the efficacy of pharmacists' assessment and intervention using the Screening Tool for Older Persons' Appropriate Prescriptions for Japanese (STOPP-J) to detect and correct potentially inappropriate medications (PIM) compared with the Screening Tool of Older Persons' Potentially Inappropriate Prescriptions (STOPP) criteria version 2. METHODS: A prospective observational study was carried out at a medical unit of Cardiovascular Surgery and Cardiovascular Internal Medicine in a Japanese university hospital involving new inpatients aged ≥65 years prescribed one or more daily medication. Pharmacists detected PIM based on STOPP-J and STOPP criteria version 2, and corrected them with physicians. The number of patients with PIM, the content and changes in PIM were compared between both criteria. RESULTS: Overall, 230 patients were included (mean age 75.4 years, 162 men, mean number of medications 8.3). STOPP-J detected significantly more patients with PIM than STOPP criteria version 2 (122 [53%] vs 75 [33%], P < 0.001). The number of PIM based on STOPP-J was 232, the physicians were recommended to change 61 (26%) and 50 (22%) were changed. Meanwhile, the number of PIM based on STOPP criteria version 2 was 133, the physicians were recommended to change 61 (46%) and 54 (41%) were changed. Several medications detected as PIM using STOPP-J were not detected using STOPP criteria version 2. CONCLUSIONS: STOPP-J detected significantly more patients with PIM than STOPP criteria version 2, and pharmacists' assessment and intervention based on STOPP-J were suggested to be effective for detecting and correcting PIM. Geriatr Gerontol Int 2019; 19: 1101-1107.

Antibiotic de-escalation therapy in patients with community-acquired nonbacteremic pneumococcal pneumonia.

Background De-escalation therapy is recommended as an effective antibiotic treatment strategy for several infectious diseases. While there is limited evidence supporting its clinical and cost-effective outcomes in patients with community-acquired bacteremic pneumonia, there is no evidence in patients with nonbacteremic pneumonia. Objective This study aimed to evaluate the antibiotic costs in patients who did and did not receive de-escalation therapy, based on the 2017 Japanese guidelines for the management of community-acquired nonbacteremic pneumococcal pneumonia of the Japanese Respiratory Society (JRS). Setting Kobe university hospital, Japan. Methods A retrospective case series review including antibiotic use and length of hospital stay was conducted using the medical records from April 2008 to May 2019 at a university hospital in Japan. Main outcome measure Impact of antibiotic de-escalation therapy on the antibiotic costs. Results Among 55 patients who were eligible, the treating physicians de-escalated antibiotics in 28 (51%). The differences in the median length of hospital stay and the incidence of adverse drug reactions between the two groups were not statistically significant (p = 0.67 and 1.0, respectively). However, the median total antibiotic cost per infected patient in the de-escalated group was significantly lower than that in the non-de-escalated group [$269.8 ($195-$389) vs. $420.5 ($221-$799), p = 0.048]. Conclusion Antibiotic de-escalation based on the 2017 JRS guidelines leads to a reduction in total antibiotic costs for the management of community-acquired nonbacteremic pneumococcal pneumonia.

A novel guidewire-integrated embolic protection filter device with a handy-folding system: In vitro and in vivo performance assessment.

OBJECTIVES: We developed a novel guidewire-integrated filter device with a handy-folding system (IFD: Inoue filter device). In vitro and in vivo studies were conducted to evaluate the feasibilityof the IFD. BACKGROUND: Although distal atheromatous and thrombotic embolizations remain unresolved critical issues during catheter interventions, distal protection devices are infrequently used partly because of reduced lower maneuverability. METHODS: In the in vitro experiment, we created an experimental circulation model composed of silicone latex tubes, a reservoir, and a roller pump. After the filter device was deployed in the tube, polystyrene fluorescent microspheres were injected and the capture rate was calculated. Ten trials were performed using the IFD and Spider FX. In the in vivo study, five independent operators deployed, and they retrieved the IFD in swine common iliac and internal carotid arteries. The procedural success rate as well as the delivery and retrieval time was evaluated. RESULTS: In the in vitro study, the mean capture rate was 94% and 35% in the IFD and Spider groups, respectively. In the in vivo study, all procedures were successful, with no complications. The mean delivery time was 281 ± 87 s and 194 ± 67 s and the mean retrieval time was 24 ± 9 and 13 ±1 s in the left internal carotid and the left common iliac arteries, respectively. CONCLUSION: Although further studies and improvements are required, the study results indicate that the IFD is feasible.

Fate of post-procedural malapposition of everolimus-eluting polymeric bioresorbable scaffold and everolimus-eluting cobalt chromium metallic stent in human coronary arteries: sequential assessment with optical coherence tomography in ABSORB Japan trial.

Aims: The natural course of post-procedural incomplete strut apposition (ISA) after the implantation of bioresorbable scaffolds (BVS) remains unknown. The purpose of the present study was to evaluate the fate of post-procedural ISA after everolimus-eluting Absorb BVS in comparison with the second-generation everolimus-eluting cobalt chromium stent (CoCr-EES). Methods and results: Fate of post-procedural ISA was evaluated by serial optical coherence tomography (OCT) in the ABSORB Japan randomized trial [OCT-1 subgroup: 110 paired lesions of post-procedure and 2-year follow-up (BVS 73 lesions vs. CoCr-EES 37 lesions)] with respect to ISA distance. Post-procedure ISA struts were categorized into either 'resolved' or 'persistent' by matched OCT imaging at 2-year follow-up. Post-procedure %malapposed strut and ISA area were smaller in BVS than in CoCr-EES (%malapposed strut: 4.8 ± 6.9% vs. 9.9 ± 9.8%, P = 0.002; ISA area 0.10 ± 0.18 mm2 vs. 0.23 ± 0.26 mm2, P = 0.003). At 2-year follow-up, the difference diminished, and majority of the ISA struts spontaneously resolved in both arms (%malapposed strut: 0.10 ± 0.46% vs. 0.24 ± 0.65%, P = 0.183). Receiver operating characteristic curve analysis (BVS 661 struts vs. CoCr-EES 807 struts) demonstrated that the best cut-off value of endoluminal ISA distance post-procedure for predicting persistent-ISA at 2-year follow-up was 396 µm for BVS (sensitivity 0.875; specificity 0.851) and 359 µm for CoCr-EES (sensitivity 0.778; specificity 0.881). Conclusion: BVS as compared with CoCr-EES allows larger ISA distance at post-procedure, although we should make every effort to minimize post-procedure ISA. The reported cut-off value of OCT-estimated ISA distance at post-stenting for predicting persistent-ISA would be helpful to optimize PCI with BVS and CoCr-EES.

Multislice computed tomography assessment of everolimus-eluting Absorb bioresorbable scaffolds in comparison with metallic drug-eluting stents from the ABSORB Japan randomised trial.

AIMS: Blooming artefacts limit accurate coronary assessment by multislice computed tomography (MSCT) in metallic stents. We sought to investigate whether bioresorbable vascular scaffolds (BVS) could be better assessed by MSCT. METHODS AND RESULTS: Among 400 patients in the randomised ABSORB Japan trial, a pre-specified MSCT substudy was performed in 98 patients (103 lesions) in the BVS arm and 49 patients (49 lesions) in the cobalt-chromium everolimus-eluting stent (CoCr-EES) arm at 13 months prior to follow-up angiography. The assessability of BVS by MSCT was superior to that of CoCr-EES (94% versus 67%, p<0.001). Blooming artefacts were the main reason CoCr-EES could not be analysed (29%), while marker artefacts precluded analysis in 1.1% of BVS. In the CoCr-EES arm, non-assessable lesions were more prevalent in segments with 2.5 mm stents compared to 3.0 or 3.5 mm stents (75.0% versus 23.5%, p=0.01), while in the BVS arm image quality was good regardless of the diameter. The in-device minimal lumen diameter by MSCT was smaller than that by QCA with a difference of 0.61 mm in the CoCr-EES arm, vs. only 0.026 mm in the BVS arm. CONCLUSIONS: The feasibility of MSCT assessment of BVS-treated lesions was greater than that for lesions with CoCr-EES.

Reassessing the Ecology of Medical Care in Japan.

Studies on ecology of medical care can provide valuable information on how people seek healthcare in a specific geographic area. The objective of this study was to update a 2003 report on the ecology of medical care in Japan, identifying relevant changes in healthcare patterns. We collected information based on a prospective health diary recorded for a month in 2013 (n = 4548; 3787 adults and 797 children) using a population-weighted random sample from a nationally representative panel. We compared our overall and stratified findings with a similar study conducted in 2003. During a one-month period, per 1000 adults and children living in Japan, we estimated that 794 report at least one symptom, 447 use an over-the-counter (OTC) drug, 265 visit a physician's office, 117 seek help from a professional provider of complementary or alternative medicine (CAM), 70 visit a hospital outpatient clinic (60 community-based and 10 university-based), 6 are hospitalized, and 4 visit a hospital emergency department. After adjusting for demographic variables, we found that healthcare seeking behaviors were influenced by age, gender and area of living. Compared with the 2003 study, participants in this study had fewer symptoms, fewer physician and emergency room visits, and less OTC use, but reported higher frequency of CAM use (p < .01 for all). Compared with 2003, reported symptoms, physician visits and OTC use has decreased, while CAM use has increased. Our findings may be useful to policymakers in Japan in a context where healthcare expenditure and a rapidly aging population are two challenging issues.

[Selection of Laboratory Procedures to Detect Toxigenic by the 2-Step Method].

The 2-step method is an algorithm to detect toxigenic Clostridium difficile. We herein compared the sensitivities and specificities of an enzyme immunoassay (toxin A/B-EIA), toxigenic culture (TC-EIA), Loop-Mediated Isothermal Amplification assay (LAMP), and Xpert C. difficile (Xpert) with the detection of the toxin B gene by a polymerase chain reaction (PCR). The results obtained showed that the sensitivities and specificities of toxin A/B-EIA, Xpert, TC-EIA, and LAMP were 30 and 100%, 87.2 and 100%, 97.5 and 89.7%, and 95 and 100%, respectively. We also evaluated the turnaround time (TAT) and cost of toxigenic C. difficile detection. Our hospital TAT for toxin A/B-EIA and TC-EIA are 37 min and 5 days, respectively. We estimated the TAT of Xpert, LAMP, and PCR to be 105 min, 5 days, and 6 days, respectively. On the other hand, the cost to detect toxigenic C. difficile increased in the order of TC-EIA, LAMP, Xpert, and PCR. We have never experienced outbreak of Clostridium difficile infection (CDI) in our hospital, and there is less the number of CDI than other place. So we selected TC-EIA that is good sensitivity and low cost per specimen. Hereafter it'll be necessary to solve a problem it takes time, because we have to respond to outbreak of CDI quickly if it happens.

[Susceptibility of clinically-isolated bacteria strains to respiratory quinolones and evaluation of antimicrobial agent efficacy by Monte Carlo simulation].

Respiratory quinolones (RQs) are broad-spectrum antimicrobial agents used for the treatment of a wide variety of community-acquired and nosocomial infections. However, bacterial resistance to quinolones has been on the increase. In this study, we investigated the predicted efficacy of RQs for various strains of 9 bacterial species clinically isolated at our university hospital using the Monte Carlo simulation (MCS) method based on pharmacokinetics/pharmacodynamics modeling. In addition, the influence of the patients' renal function on the efficacy of RQs was evaluated. We surveyed antimicrobial susceptibility testing of 9 bacterial species (n = number of strains) [Streptococcus pneumoniae (n = 15), Streptococcus pyogenes (n = 14), Streptococcus agalactiae (n = 19), methicillin-susceptible Staphylococcus aureus (MSSA) (n = 24), Escherichia coli (n = 35), Haemophilus influenzae (n = 17), Klebsiella pneumoniae (n = 14), Pseudomonas aeruginosa (n = 31), and Moraxella catarrhalis (n = 11)] to 4 RQs [garenoxacin (GRNX), levofloxacin (LVFX), sitafloxacin (STFX), and moxifloxacin (MFLX)]. We found that compared with the other RQs, Gram-positive cocci was most resistant to LVFX, and that the minimum inhibitory concentration (MIC90) values for S. pneumoniae, S. pyogenes, S. agalactiae, and MSSA were high (2, 16, > 16, and 8 µg/mL, respectively). In regard to Gram-negative rods, the susceptibility of E. coli to RQs was found to be decreased, with the MIC90 values of GRNX, LVFX, STFX, and MFLX being > 16, 16, 1, and 16 µg/mL, respectively. MCS revealed that the target attainment rate of the area under the unbound concentration-time curve divided by the MIC90 (ƒ · AUC/MIC ratio), against S. pneumoniae was 86.9-100%, but against E. coli was low (52.1-66.2%). The ƒ · AUC/MIC target attainment rate of LVFX against S. pneumoniae, S. pyogenes, and S. agalactiae tended to decrease due to increased creatinine clearance, and that of LVFX and STFX against MSSA also tended to decrease. The findings of this study suggest that the drug susceptibility distribution of each RQ varies, even within the same bacterial species, and that the expected efficacy also varies between the drugs. Moreover, the influence of the patient's renal function on the efficacy differed among the 3 renal excretory drugs (GRNX, LVFX, and STFX), thus suggesting that the efficacy also differs. In conclusion, the findings of this study show that for the administration of RQs, it is desirable to select agents in consideration of surveyed sensitivity within the population and the pharmacokinetic characteristics.

Impact of Total Risk Management on Coronary Plaque Regression in Diabetic Patients with Acute Coronary Syndrome.

AIM: Diabetic patients with coronary artery disease have a high incidence of cardiovascular events, which was associated with increased coronary plaque volume. Low-density lipoprotein cholesterol (LDL-C) and blood pressure (BP) play pivotal roles in the progression of coronary plaque. Several trials have shown that intervention for a single risk factor reduced the development of coronary plaque progression. However, it remained uncertain whether total risk management for LDL-C, BP, and glycosylated Hb (HbA1c) has a beneficial effect on coronary plaque volume in diabetic patients. METHODS: This study was a sub-study of the JAPAN-ACS that was a prospective, randomized, open-label trial that evaluated the impact of intensive lipid-lowering therapy on coronary plaque volume in patients with acute coronary syndrome (ACS). Among a total of 252 patients, 73 diabetic patients were analyzed. We examined the impact of total risk management (LDL-C ＜80 mg/dL, systolic BP ＜130 mmHg, and HbA1c ＜6.5%) on changes in coronary plaque volume. The patients were divided into four groups according to the number of risk factors that achieved the target value. RESULTS: Baseline characteristics were similar among the groups. The degree of coronary plaque regression was greater in patients who achieved total risk management. The number of risk factors that achieved the target level was associated with the extent of the coronary plaque volume reduction in a dose-dependent manner. CONCLUSION: Total risk management that focused on LDL-C, BP, and HbA1c had a beneficial impact on the coronary plaque regression in diabetic patients with ACS.

Quantitative assessment of the stent/scaffold strut embedment analysis by optical coherence tomography.

The degree of stent/scaffold embedment could be a surrogate parameter of the vessel wall-stent/scaffold interaction and could have biological implications in the vascular response. We have developed a new specific software for the quantitative evaluation of embedment of struts by optical coherence tomography (OCT). In the present study, we described the algorithm of the embedment analysis and its reproducibility. The degree of embedment was evaluated as the ratio of the embedded part versus the whole strut height and subdivided into quartiles. The agreement and the inter- and intra-observer reproducibility were evaluated using the kappa and the interclass correlation coefficient (ICC). A total of 4 pullbacks of OCT images in 4 randomly selected coronary lesions with 3.0 × 18 mm devices [2 lesions with Absorb BVS and 2 lesions with XIENCE (both from Abbott Vascular, Santa Clara, CA, USA)] from Absorb Japan trial were evaluated by two investigators with QCU-CMS software version 4.69 (Leiden University Medical Center, Leiden, The Netherlands). Finally, 1481 polymeric struts in 174 cross-sections and 1415 metallic struts in 161 cross-sections were analyzed. Inter- and intra-observer reproducibility of quantitative measurements of embedment ratio and categorical assessment of embedment in Absorb BVS and XIENCE had excellent agreement with ICC ranging from 0.958 to 0.999 and kappa ranging from 0.850 to 0.980. The newly developed embedment software showed excellent reproducibility. Computer-assisted embedment analysis could be a feasible tool to assess the strut penetration into the vessel wall that could be a surrogate of acute injury caused by implantation of devices.

In vitro assessment of physiological impact of recipient artery intervention on the contralateral donor artery.

BACKGROUND: Donor artery fractional flow reserve (FFR) often improves after treatment of recipient artery stenosis, but the physiological mechanism underlying this phenomenon has not been elucidated. This study aimed to assess two novel equations that explain the donor-recipient artery interaction. METHOD: Eq. (A) predicts the donor artery FFR after complete release of recipient artery stenosis, while Eq. (B) predicts the donor artery FFR after partial release of recipient artery stenosis. Eq. (B) is a general form of Eq. (A). FFR'1−pred = ((FFR1−CFI1)(FFR2−CFI2)−CFI1CFI2(1−FFR1)(1−FFR2)+CFI1(1−FFR1)(1−CFI2))/((1−C FI1)(FFR2−CFI2)) (A) FFR''1−pred = ((FFR1−CFI1)(FFR2−CFI2)−CFI1CFI2(1−FFR1)(1−FFR2)+CFI1(1−FFR1)(1−CFI2))FFR'2/((1−C FI1)(FFR2−CFI2)) (B) Eqs. (A) and (B) were assessed using an in vitro model of coronary circulation with a collateral channel connecting the donor and recipient arteries. RESULTS: The donor artery FFR always improved after releasing the recipient artery stenosis. A good linear correlation was found between the predicted FFR of Eq. (A) and the actual FFR (n=40, r=0.95, p<0.0001) and between the predicted FFR of Eq. (B) and the actual FFR (n=40, r=0.94, p<0.0001). CONCLUSIONS: Eqs. (A) and (B) accurately predicted the true FFR value of the donor artery in a coronary circulation model and explain the donor-recipient artery interaction observed in clinical practice.

Effect of radiofrequency catheter ablation of persistent atrial fibrillation on the left atrial function: assessment by 320-row multislice computed tomography.

BACKGROUND: Atrial fibrillation (AF) increases the left atrial (LA) volume and deteriorates LA function. Whether successful radiofrequency catheter ablation (RFCA) of persistent AF can reverse this process has not been yet established. METHODS: Patients with persistent AF undergoing RFCA were evaluated with pre- and post- (at 6-months of follow-up) procedural multislice computed tomography (MSCT). The LA functions were assessed through LA time-volume curves. RESULTS: The study population consisted of 44 patients [age 64 (interquartile ranges: 58, 70) years old, 93% male]. Among those, 31 patients (70%) maintained sinus rhythm during the follow-up (no recurrence group; NR group). The remaining 13 patients were classified as the recurrence group (R group). A significant decrease in the minimal and maximal LA volumes was observed in both groups, although this was less pronounced in the R group. Only the NR group had an improvement in the LA expansion index [18% (13, 25) vs. 37% (23, 43), p<0.001], ejection fraction [15% (11, 20) vs. 27% (19, 30), p<0.001] and conduit function [17 ml/m(2) (13, 20) vs. 25 ml/m(2) (20, 34), p<0.001]. An improvement of LV function was also observed only in the NR group. CONCLUSIONS: LA anatomical and functional reverse remodeling after RFCA of persistent AF was demonstrated by MSCT during follow-up, which was more pronounced in patients without AF recurrence.

Cost analysis of non-invasive fractional flow reserve derived from coronary computed tomographic angiography in Japan.

Percutaneous coronary intervention (PCI) based on fractional flow reserve (FFRcath) measurement during invasive coronary angiography (CAG) results in improved patient outcome and reduced healthcare costs. FFR can now be computed non-invasively from standard coronary CT angiography (cCTA) scans (FFRCT). The purpose of this study is to determine the potential impact of non-invasive FFRCT on costs and clinical outcomes of patients with suspected coronary artery disease in Japan. Clinical data from 254 patients in the HeartFlowNXT trial, costs of goods and services in Japan, and clinical outcome data from the literature were used to estimate the costs and outcomes of 4 clinical pathways: (1) CAG-visual guided PCI, (2) CAG-FFRcath guided PCI, (3) cCTA followed by CAG-visual guided PCI, (4) cCTA-FFRCT guided PCI. The CAG-visual strategy demonstrated the highest projected cost ($10,360) and highest projected 1-year death/myocardial infarction rate (2.4 %). An assumed price for FFRCT of US $2,000 produced equivalent clinical outcomes (death/MI rate: 1.9 %) and healthcare costs ($7,222) for the cCTA-FFRCT strategy and the CAG-FFRcath guided PCI strategy. Use of the cCTA-FFRCT strategy to select patients for PCI would result in 32 % lower costs and 19 % fewer cardiac events at 1 year compared to the most commonly used CAG-visual strategy. Use of cCTA-FFRCT to select patients for CAG and PCI may reduce costs and improve clinical outcome in patients with suspected coronary artery disease in Japan.

In vitro assessment of mathematically-derived fractional flow reserve in coronary lesions with more than two sequential stenoses.

BACKGROUND: Myocardial fractional flow reserve (FFR) is a reliable index in coronary intervention. A simple FFR measurement does not predict the true functional severity of an individual stenosis in multiple sequential coronary stenoses because of complex interaction between the stenoses. Application of the theoretical equations to predict the true FFR of individual stenosis is limited in a tandem lesion. Two novel equations applicable to a multiple sequential coronary stenoses are mathematically derived. One predicts the true FFR of each stenosis (equation A), and the other predicts the true FFR after releasing a given stenosis (equation B). The present study aimed to validate the two derived equations in an in vitro model of coronary circulation. METHODS AND RESULTS: Predictive FFR was compared with true FFR in an in vitro model of three sequential stenoses using linear regression analysis. The difference between apparent FFR and true FFR was compared with the difference between predictive FFR and true FFR. The legitimacy of equation A was first assessed. A close correlation was found between predictive FFR and true FFR (r² = 0.92). The difference between predictive FFR and true FFR was significantly lower compared to the difference between apparent FFR and true FFR (0.18 ± 0.10 vs 0.05 ± 0.05; P<.001). The legitimacy of equation B was also assessed, and a close correlation was found (r² = 0.97). The difference was significantly lower when we applied equation B (0.13 ± 0.06 vs 0.04 ± 0.02; P<.001). CONCLUSIONS: Equations A and B strongly predict the true value of FFR in the experimental model of coronary circulation.