Correlation between the spread of IMP-producing bacteria and the promoter strength of blaIMP genes

The first report of transmissible carbapenem resistance encoded by blaIMP-1 was discovered in Pseudomonas aeruginosa GN17203 in 1988, and blaIMP-1 has since been detected in other bacteria, including Enterobacterales. Currently, many variants of blaIMPs exist, and point mutations in the blaIMP promoter have been shown to alter promoter strength. For example, the promoter (Pc) of blaIMP-1, first reported in P. aeruginosa GN17203, was a weak promoter (PcW) with low-level expression intensity. This study investigates whether point mutations in the promoter region have helped to create strong promoters under antimicrobial selection pressure. Using bioinformatic approaches, we retrieved 115 blaIMPs from 14,529 genome data of Pseudomonadota and performed multiple alignment analyses. The results of promoter analysis of the 115 retrieved blaIMPs showed that most of them used the Pc located in class 1 integrons (n = 112, 97.4%). The promoter analysis by year revealed that the blaIMP population with the strong promoter, PcS, was transient. In contrast, the PcW-TG population, which had acquired a TGn-extended -10 motif in PcW and had an intermediate promoter strength, gradually spread throughout the world. An inverse correlation between Pc promoter strength and Intl1 integrase excision efficiency has been reported previously [1]. Because of this trade-off, it is unlikely that blaIMPs with strong promoters will increase rapidly, but the possibility that promoter strength will increase with the use of other integrons cannot be ruled out. Monitoring of the blaIMP genes, including promoter analysis, is necessary for global surveillance of carbapenem-resistant bacteria.

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

Actinomycetes are well-known as the main producers of bioactive compounds such as antibiotics, anticancers, and immunosuppressants. Screening of natural products from actinomycetes has been an essential part of several drug discovery programs. Finding such novel biologically active metabolites is immensely important because of their beneficial health effects. Recently, the discovery of new compounds has diverted attention to rare actinomycetes, since they are rich sources of natural products. In this study, a collection of rare actinomycetes at Kitasato University has been screened for potential novel compound producers. Among the rare actinomycetes, Saccharopolyspora sp. KR21-0001 isolated from soil on Ōha Island, Okinawa, Japan was selected as a potential producer. The strain was cultured in 20 L of production medium in a jar fermenter and the culture broth was extracted. Further purification revealed the presence of a new compound designated KR21-0001A (1). The structure was elucidated by NMR, and the absolute stereochemistry was determined by advanced Marfey's method. The results indicated that 1 is a new analog of dihydroxybenzoic acid. 1 has no antimicrobial activity against bacteria and fungi but showed potent antioxidant activity.

Akedanones A-C, In Vitro and In Vivo Antiplasmodial 2,3-Dihydronaphthoquinones Produced by Streptomyces sp. K20-0187

Three new antiplasmodial compounds, named akedanones A (1), B (2), and C (3), were discovered from the cultured material of Streptomyces sp. K20-0187 isolated from a soil sample collected at Takeda, Kofu, Yamanashi prefecture in Japan. The structures of compounds 1-3 were elucidated as new 2,3-dihydronaphthoquinones having prenyl and reverse prenyl groups by mass spectrometry and nuclear magnetic resonance analyses. Compound 1 and the known furanonaphthoquinone I (4) showed potent in vitro antiplasmodial activity against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains, with half-maximal inhibitory concentration values ranging from 0.06 to 0.3 μM. Compounds 1 and 4 also displayed potent in vivo antiplasmodial activity against drug-sensitive rodent malaria Plasmodium berghei N strain, with inhibition rates of 47.6 and 43.1%, respectively, on intraperitoneal administration at a dose of 5 mg kg-1 day-1 for 4 days.

Bail-Out TEVAR through a Branch of Four-Arm Dacron Graft for Misdeployment of a Frozen Elephant Trunk Prosthesis

The frozen elephant trunk (FET) is an effective method for making the distal anastomosis more proximal and facilitating aortic remodeling in acute aortic dissection. However, misdeployment of FET to the false lumen has been reported in several cases. Such cases are usually treated with bail-out thoracic endovascular aortic repair (TEVAR) through the femoral artery or additional FET under direct vision to redirect the blood flow to the true lumen. We encountered a case of misdeployment of FET into the false lumen during open aortic surgery for the treatment of Stanford type A acute aortic dissection. After reconstruction of the aorta and all arch vessels, we performed antegrade bail-out TEVAR through a side branch of the four-arm Dacron graft as main access using a pull-through technique through the right femoral artery, which was perfused from the true lumen. This technique, which uses a Dacron graft branch for stent graft access, enabled us to confirm the true lumen because the distal anastomotic site was definitely the true lumen, and we were also able to avoid access difficulties at the iliac artery.

Emblestatin: a new peptide antibiotic from Embleya scabrispora K20-0267

A new peptide, emblestatin (1), was discovered from a culture broth of Embleya scabrispora K20-0267. This strain was isolated from soil using an agar medium containing lysozyme. Based on NMR and mass spectrometric analyses, 1 consists of 2-(2-hydroxyphenyl)-2-oxazoline, β-alanine, glutamine, Nα-methyl-Nω-hydroxyornithine and 3-amino-1-hydroxy-2-piperidone moieties. Further analysis using the advanced Marfey's method revealed that all amino acids with the stereogenic α-carbon in 1 had the L configuration. Compound 1 exhibited iron chelating activity and weak antibacterial activity against Proteus vulgaris and Staphylococcus aureus.

Transapical ventricular reshaping reduces functional mitral regurgitation and improves ventricular function in a preclinical model of ischemic cardiomyopathy

OBJECTIVE

A significant proportion of patients with advanced heart failure present with dilated left ventricles and functional mitral regurgitation. These patients currently have limited treatment options. The MitraClip device (Abbott) has benefited only patients with smaller left ventricles (end-diastolic dimension <70 mm), whereas those with larger left ventricles did not benefit. A possible explanation is correcting functional mitral regurgitation alone may not adequately reduce the wall stresses of a dilated left ventricle. We have developed a beating-heart device that not only approximates the papillary muscles to reduce functional mitral regurgitation but also modifies the left ventricle size and shape to reduce wall stress.

METHODS

Yorkshire swine (n = 16) had a myocardial infarction induced by permanent occlusion of the left circumflex with intracoronary ethanol. Three months later, the animals developed heart failure and moderate or greater functional mitral regurgitation. Through a transapical approach, the new device was implanted under echocardiography guidance to reshape the left ventricle and correct functional mitral regurgitation. The acute impact of this approach on the mitral valve and left ventricle was assessed with echocardiography and invasive hemodynamics.

RESULTS

After reshaping, echocardiography showed a decrease in end-diastolic volume by 36.3 ± 30.5 mL (P < .001), a decrease in sphericity index by 0.143 ± 0.087 (P < .001), and an increase in ejection fraction of 5.90% ± 6.38% (P < .01). Mitral valve tenting area was reduced by 39.29 ± 33.66 mm2 (P < .001), coaptation length was increased by 2.12 ± 1.02 mm (P < .001), and posterior excursion angle was improved by 9.07° ± 9.14° (P < .01), resulting in functional mitral regurgitation reduction.

CONCLUSIONS

Correction of functional mitral regurgitation with favorable changes in mitral valve geometry and reduction in left ventricle geometry is possible with the proposed device.

Impella Implantation as a Bridge to Surgery for Repair of Aorto-Right Ventricular Fistula Following Prosthetic Valve Endocarditis: A Case Report

For patients with cardiogenic shock, delaying surgery with mechanical circulatory support is reported to yield better outcomes than emergency surgery. We report on an 82-year-old man diagnosed with vertebral osteomyelitis with concomitant infective endocarditis. Chest radiographs revealed a growing abscess, which resulted in an aorto-right ventricular fistula. Providing Impella support allowed for hemodynamic stabilization prior to surgery. The patient had an uneventful postoperative course and reported to be well in a follow-up 1 year later. Impella support can be used as a bridge to surgery for repairing fistulous tract formation in patients in cardiogenic shock.

Comprehensive analysis of biosynthetic gene clusters in bacteria and discovery of Tumebacillus as a potential producer of natural products

Limited microbial genera such as Streptomyces have served as sources of natural products (NPs), whereas most others have been less investigated. The vast accumulation of genomic data available in the NCBI database enables us to bioinformatically estimate the ability of other microbial groups to produce NPs. We analyzed 21,052 complete bacterial genome sequences using antiSMASH and compared the average numbers of biosynthetic gene clusters (BGCs) related to polyketides, non-ribosomal peptides, and/or terpenes biosynthesis at the genus level. Our bioinformatic analyses showed that Tumebacillus has 5-15 BGCs and is a promising NP producer. We searched for NPs from the culture broth of Tumebacillus permanentifrigoris JCM 14557^T and found two novel compounds (tumebacin with anti-Bacillus activity and tumepyrazine) and identified two known compounds. Our results highlight the diversity of sources of NPs awaiting discovery.

Proximal and extended aortic arch replacement in acute DeBakey type I aortic dissection

Objective

This study aimed to compare the short- and long-term outcomes of proximal repair vs. extensive arch surgery for acute DeBakey type I aortic dissection.

Subjects

From April 2014 to September 2020, 121 consecutive patients with acute type A dissection were surgically treated at our institute. Of these patients, 92 had dissections extending beyond the ascending aorta.

Methods

Of the 92 patients, 58 underwent proximal repair, including aortic root and/or hemiarch replacement, and 34 underwent extended repair, including partial and total arch replacement. Perioperative variables and early and late postoperative results were statistically analyzed.

Results

The duration of surgery, cardiopulmonary bypass, and circulatory arrest was significantly shorter in the proximal repair group (p < 0.01). The overall operative mortality rate was 10.3% in the proximal repair group and 14.7% in the extended repair group (p = 0.379). The mean follow-up period was 31.1 ± 26.7 months in the proximal repair group and 35.3 ± 26.8 months in the extended repair group. During follow-up, the cumulative survival and freedom from reintervention rates at 5 years were 66.4% and 92.9% in the proximal repair group, and 76.1% and 72.6% in the extended repair group, respectively (p = 0.515 and p = 0.134).

Conclusions

No significant differences were found in the rates of long-term cumulative survival and freedom from aortic reintervention between the two surgical strategies. These findings suggest limited aortic resection achieves acceptable patient outcomes.

Mesenteric Ischemia After Cardiac Surgery in Dialysis Patients: An Overlooked Risk Factor

Background: No study has examined the association of the calcification of abdominal artery orifices with nonocclusive mesenteric ischemia (NOMI) in dialysis patients undergoing cardiac surgery. Thus, this study aimed to determine whether calcification of abdominal blood vessel orifices in hemodialysis patients may be a risk factor for NOMI and examine the long-term survival of dialysis patients after undergoing cardiac surgery. Methods: From April 2014 to September 2020, 100 dialysis patients underwent cardiac surgery at our hospital. The calcification of the celiac artery (CA) and superior mesenteric artery (SMA) was evaluated by computed tomography, and the degree of orifice stenosis was graded as follows: patent, 0; partial occlusion, 1; and complete occlusion, 2. Results: Eight patients experienced NOMI, and all of them died. SMA calcification scores were not significantly different between the NOMI and non-NOMI groups (1.38±0.52 vs. 1.13±0.69; P = 0.247). However, the average CA orifice calcification score was significantly greater in the NOMI group than in the non-NOMI group (1.63±0.52 vs. 1.15±0.65; P = 0.039), and the SMA+CA orifice calcification scores were significantly different between the groups (3.00±0.76 vs. [non-NOMI] 2.25±1.18; P = 0.028). In all patients, the 30-day and in-hospital mortality rates were 13% and 18%, respectively. All patients were completely followed up with a mean follow-up period of 604±585 days. Kaplan–Meier survival curves showed that patients with SMA and CA calcification tended to have a shorter overall survival than patients without calcification; however, no significant difference was noted. Conclusions: The calcification of CA and/or SMA orifices was associated with postoperative NOMI and poor long-term survival among dialysis patients undergoing cardiac surgery.

Efficient secretory production of proline/alanine/serine (PAS) biopolymers in Corynebacterium glutamicum yielding a monodisperse biological alternative to polyethylene glycol (PEG)

Background

PAS biopolymers are recombinant polypeptides comprising the small uncharged l-amino acids Pro, Ala and/or Ser which resemble the widely used poly-ethylene glycol (PEG) in terms of pronounced hydrophilicity. Likewise, their random chain behaviour in physiological solution results in a strongly expanded hydrodynamic volume. Thus, apart from their use as fusion partner for biopharmaceuticals to achieve prolonged half-life in vivo, PAS biopolymers appear attractive as substitute for PEG—or other poorly degradable chemical polymers—in many areas. As a prerequisite for the wide application of PAS biopolymers at affordable cost, we have established their highly efficient biotechnological production in Corynebacterium glutamicum serving as a well characterized bacterial host organism.

Results

Using the CspA signal sequence, we have secreted two representative PAS biopolymers as polypeptides with ~ 600 and ~ 1200 amino acid residues, respectively. Both PAS biopolymers were purified from the culture supernatant by means of a simple downstream process in a truly monodisperse state as evidenced by ESI–MS. Yields after purification were up to ≥ 4 g per liter culture, with potential for further increase by strain optimization as well as fermentation and bioprocess development. Beyond direct application as hydrocolloids or to exploit their rheological properties, such PAS biopolymers are suitable for site-specific chemical conjugation with pharmacologically active molecules via their unique terminal amino or carboxyl groups. To enable the specific activation of the carboxylate, without interference by the free amino group, we generated a blocked N-terminus for the PAS(1200) polypeptide simply by introducing an N-terminal Gln residue which, after processing of the signal peptide, was cyclised to a chemically inert pyroglutamyl group upon acid treatment. The fact that PAS biopolymers are genetically encoded offers further conjugation strategies via incorporation of amino acids with reactive side chains (e.g., Cys, Lys, Glu/Asp) at defined positions.

Conclusions

Our new PAS expression platform using Corynex^® technology opens the way to applications of PASylation^® technology in multiple areas such as the pharmaceutical industry, cosmetics and food technology.

Modified turn-up technique for proximal anastomosis in acute aortic dissection type A has potential to facilitate stable outcomes for low-volume early-career surgeons

Objective

Secure proximal anastomosis is an essential part of surgical treatment for acute aortic dissection type A (AADA). This study aimed to investigate the effectiveness of the modified turn-up technique for proximal anastomosis in AADA and compare this technique with other techniques.

Methods

We divided 57 patients who underwent ascending aorta replacement for AADA into the modified turn-up technique group (group A: 36 patients) and the other technique group (group B: 21 patients). Intraoperative and postoperative course data were compared between groups A and B. In group A, we also compared early-career surgeons (practicing for <10 years after graduation) and aged surgeons (practicing for ≥10 years after graduation).

Results

Preoperative patient characteristics did not differ between groups. There was a tendency toward shorter operation time in group A than in group B without statistical significance (p = 0.12), and the length of intensive care unit stay was significantly shorter (p < 0.01); the occurrence of cerebral infarction was lower (p < 0.01) in group A than in group B, whereas mortality and major complications other than the cerebral infarction rate did not differ between the groups. In group A, 13 patients were operated on by early-career surgeons, while 23 patients were operated on by surgeons with more than 10 years of experience. Aortic clamp time and circulatory arrest time were significantly longer in patients operated on by early-career surgeons, but outcomes were comparable.

Conclusions

The modified turn-up technique was comparable to other techniques. Even for less skilled surgeons (e.g., early-career surgeons), the use of this technique may lead to stable outcomes.

Polyvinyl alcohol coating prevents platelet adsorption and improves mechanical property of polycaprolactone-based small-caliber vascular graft

The low patency of synthetic vascular grafts hinders their practical applicability. Polyvinyl alcohol (PVA) is a non-toxic, highly hydrophilic polymer; thus, we created a PVA-coated polycaprolactone (PCL) nanofiber vascular graft (PVA–PCL graft). In this study, we examine whether PVA could improve the hydrophilicity of PCL grafts and evaluate its in vivo performance using a rat aorta implantation model. A PCL graft with an inner diameter of 1 mm is created using electrospinning (control). The PCL nanofibers are coated with PVA, resulting in a PVA–PCL graft. Mechanical property tests demonstrate that the PVA coating significantly increases the stiffness and resilience of the PCL graft. The PVA–PCL surface exhibits a much smaller sessile drop contact angle when compared with that of the control, indicating that the PVA coating has hydrophilic properties. Additionally, the PVA–PCL graft shows significantly less platelet adsorption than the control. The proposed PVA–PCL graft is implanted into the rat’s abdominal aorta, and its in vivo performance is tested at 8 weeks. The patency rate is 83.3% (10/12). The histological analysis demonstrates autologous cell engraftment on and inside the scaffold, as well as CD31/α-smooth muscle positive neointima regeneration on the graft lumen. Thus, the PVA–PCL grafts exhibit biocompatibility in the rat model, which suggests that the PVA coating is a promising approach for functionalizing PCL.

Post-cardiotomy pericardial effusion and postoperative atrial fibrillation risk

Postoperative atrial fibrillation is a poor prognostic factor associated with increased mortality rates. Patients experiencing significant pericardial effusion develop postoperative atrial fibrillation; however, little is explored about the association between postoperative atrial fibrillation and post-cardiotomy pericardial effusion. This retrospective, single-center study included adult patients who underwent cardiovascular surgery via median sternotomy from January 2016 to December 2019. Patients who underwent routine postoperative computed tomography at 7 ± 3 days after surgery (n = 294) were included. Pericardial effusion was measured at the thickest point. Patients were classified into those with (n = 127) and without (n = 167) postoperative atrial fibrillation. The association of pericardial effusion with other factors was evaluated. A possible confounder-adjusted logistic regression analysis after multiple imputation was performed to obtain odds ratios for postoperative atrial fibrillation using previously published risk factors. Age, intraoperative bleeding volume, and pericardial effusion size were all significantly higher in the group with postoperative atrial fibrillation. Multivariate logistic regression after multiple imputation revealed that age, intraoperative bleeding volume, and postoperative pericardial effusion were significantly associated with postoperative atrial fibrillation. Our findings suggest that post-cardiotomy pericardial effusion is associated with postoperative atrial fibrillation. However, the causality remains unknown, making further studies mandatory.

Insulin therapy maintains the performance of PVA-coated PCL grafts in a diabetic rat model

Vascular tissue engineering has shown promising results in "healthy" animal models. However, studies on the efficacy of artificial grafts under "pathological conditions" are limited. Therefore, in this study, we aimed to characterize the performance of polyvinyl alcohol (PVA)-coated poly-ε-caprolactone (PCL) grafts (PVA-PCL grafts) under diabetic conditions. To this end, PCL grafts were produced via electrospinning and coated with the hydrophilic PVA polymer, while a diabetic rat model (DM) was established via streptozotocin injection. Thereafter, the performance of the graft in the infrarenal abdominal aorta of the rats was evaluated in vivo. Thus, we observed that the healthy group showed CD31 positive/αSM positive cells in the graft lumen. Further, the patency rate of the PVA-PCL graft was 100% at 2 weeks (n = 7), while all the DM rats (n = 8) showed occluded grafts. However, the treatment of DM rats with neutral protamine Hagedorn insulin (tDM) significantly improved the patency rate (100%; n = 5). Furthermore, the intimal coverage rate corresponding to the tDM group was comparable to that of the healthy group at 2 weeks (tDM vs. healthy: 16.1% vs. 14.7%, p = 0.931). Therefore, the present study demonstrated that the performance of the PVA-PCL grafts was impaired in DM rats; however, insulin treatment reversed this impairment. These findings highlighted the importance of using a model that more closely resembles the cases that are encountered in clinical practice to achieve a clinically applicable vascular graft with a small diameter.

Silent cerebral ischemia detected by magnetic resonance imaging can predict postoperative delirium after total arch replacement for aneurysm

Objective

To identify whether preoperative magnetic resonance imaging findings of the brain can predict postoperative delirium in patients who undergo arch replacement for aneurysms.

Methods

Overall, 193 patients who underwent aortic replacement for the first time at a single institution between April 2014 and September 2020 were enrolled in this retrospective study. After we excluded patients with acute aortic dissection, no preoperative magnetic resonance imaging findings of the brain, and postoperative cerebral infarction, 50 patients were included and divided into 2 groups, according to their confusion scale results: postoperative delirium (group D) and nonpostoperative delirium (group ND). Preoperative magnetic resonance imaging findings of the brain were classified into lacunar stroke, periventricular hyperintensity, and deep subcortical white matter hyperintensity groups; the latter 2 groups were further classified based on the Fazekas scale, grade 0 to 3.

Results

There were 23 patients (46%) in group D and 27 (54%) in group ND. The mean age was significantly greater in group D than in group ND (75 vs 70 years; P = .007). The mean operative time was significantly longer in group D than in group ND (447 vs 384 minutes; P = .024). As for preoperative magnetic resonance imaging findings of the brain, there were significantly more lacunar stroke cases in group D than in group ND (P = .027). In multivariable logistic regression with stepwise selection, high-grade periventricular hyperintensity was significantly related to postoperative delirium (odds ratio, 9.38; 95% confidence interval, 1.55-56.56; P = .015).

Conclusions

Silent cerebral ischemia detected by preoperative magnetic resonance imaging of the brain was a significant risk factor for postoperative delirium.

The Impact of Chronic Limb-Threatening Ischemia on Cardiac Surgery

Purpose

The effect of chronic limb threatening ischemia (CLTI) on advanced cardiac disease, which requires surgical treatment, has rarely been reported. The purpose of this study was to review the outcomes of cardiac surgery in patients with CLTI and determine the risk factors, with a particular focus on the severity of CLTI.

Patients

The baseline characteristics and outcomes of 33 patients who were treated for CLTI and underwent cardiac surgery were retrospectively analyzed. The states of CLTI were evaluated based on the Wound, Ischemia, and foot Infection (WIfI) classification system, and 33 patients were divided into the low-WIfI group (stages 1–2, n = 13) and high-WIfI group (stages 3–4, n = 20).

Results

The in-hospital mortality rate was 0% in low-WIfI group and 35% in high-WIfI group (p = 0.027). Postoperative complications, particularly severe infections, occurred more frequently among high-WIfI group than low-WIfI group (70.0% vs. 23.1%, p < 0.01). Multivariable analysis identified foot infection grade as a WIfI classification factor and lower albumin levels as factors significantly associated with postoperative complications. The 1-year and 2-year survival rates were 84.6% and 67.7% in low-WIfI group and 45% and 28.1% in high-WIfI group, respectively (p = 0.011).

Conclusions

Cardiac surgery in patients with high WIfI stage was an extremely high-risk procedure. In such patients, lowering the WIfI stage by lower extremity revascularization and/or debridement of diseased parts prior to cardiac surgery can be considered.

The Early Introduction of Extracorporeal Membrane Oxygenation for Postcardiotomy Cardiogenic Shock Does Not Improve 30-Day Mortality Rates in Low-Volume Centers

Background and objective

Postcardiotomy cardiogenic shock (PCS) is one of the most critical conditions observed in cardiac surgery. Recently, the early initiation of venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been recommended for PCS patients to ensure end-organ perfusion, especially in high-volume centers. In this study, we investigated the effectiveness of earlier initiation of VA-ECMO for PCS in low-volume centers.

Methods

We retrospectively assessed patients admitted in two of our related facilities from April 2014 to March 2019. The patients who underwent VA-ECMO during peri- or post-cardiac surgery (within 48 hours) were included. We divided the patients into two groups according to the timing of VA-ECMO initiation. In the early initiation of VA-ECMO group, the “early ECMO group,” VA-ECMO was initiated when patients needed high-dose inotropic support with high-dose catecholamines, such as epinephrine, without waiting for PCS recovery. In the late initiation of VA-ECMO group, the “late ECMO group,” VA-ECMO was delayed until PCS was not controlled with high-dose catecholamines, with the intent of avoiding severe bleeding complications.

Results

A total of 30 patients were included in the analysis (early ECMO group/late ECMO group: 19/11 patients). Thirty-day mortality in the entire cohort was 60% (n=18), and there was no significant difference between the two groups (early ECMO group/late ECMO group: 64%/55%, p=0.712). Thirteen and six patients died without being weaned off in the early ECMO (43%) and late ECMO groups (55%), respectively; there was no significant difference between the two groups (p=0.696). The median duration of ECMO support was five days (IQR: 1.5-6.5).

Conclusions

The early initiation of ECMO did not contribute to patients’ 30-day outcomes in low-volume centers. To improve outcomes of ECMO therapy in patients with PCS, centralization of low-volume centers may be required.

Does a Small Body Have a Negative Impact on Minimally Invasive Mitral Valve Surgery?

Backgrounds

Minimally invasive mitral valve surgery (MIMVS) in patients with a small body presents surgeons with a technically difficult surgical maneuver. We hypothesized that physique might negatively influence the safety and technical complexity of MIMVS.

Methods

One hundred and twenty-one patients underwent MIMVS in our institution between May 2014 and April 2020. These patients were categorized into two groups. The first group was the small physique group (n = 20) consisting of patients with a stature &lt;150 cm. The second group was the normal physique group (n = 101) consisting of patients with a stature &gt;150 cm. The primary endpoint was freedom from death and major adverse cardiovascular and cerebrovascular events (MACCE). The secondary endpoint was freedom from moderate or severe mitral regurgitation.

Results

Cardiopulmonary bypass time (130 ± 29 vs. 156 ± 55 min, p = 0.02) and aortic cross-clamp time (75 ± 27 vs. 95 ± 39 min, p = 0.03) were significantly shorter in the small physique group. Both in the early and midterm periods, there was no significant difference in the mortality (early, 5.0 vs. 1.0%, p = 0.30. midterm, 5.0 vs. 1.0%, p = 0.09), MACCE (early, 5.0 vs. 6.9%, p = 0.65. midterm, 5.0 vs. 5.9%, p = 0.93) and the residual MR (early, 0 vs. 1.0%, p = 0.66. midterm, 5.0 vs. 4.9%, p = 0.93) between the two groups.

Conclusions

Small physique is not a hurdle for MIMVS in terms of the safety of the operation.

OUP accepted manuscript

The proper surgical strategy for retrograde type A aortic dissection (RTAD) is still controversial, and some studies have reported the efficacy of frozen elephant trunk and thoracic endovascular aortic repair (TEVAR). A 68-year-old man was diagnosed with acute type A aortic dissection using enhanced computed tomography. The false lumen at the arch and ascending aorta was thrombosed, and the primary entry was placed in the descending aorta. In addition, there were malperfusions of the right renal artery and both iliac arteries. We performed TEVAR using the right femoral artery combined with the petticoat technique. At 11 days postoperatively, we observed rapid aortic remodeling at the arch and ascending aorta. The patient was discharged uneventfully after 14 days. We believe that TEVAR for RTAD is effective in appropriate patients. However, the accumulation of the number of cases and accurate strategies for patient selection are in demand.

A case of TEVAR for acute aortic dissection after MICS AVR and retroperitoneal tumor resection

If multiple treatments are performed within a short time, when something occurs, it is difficult to identify its cause. Here, we present a case of thoracic endovascular aortic repair (TEVAR) for acute aortic dissection (AAD) after multiple treatments. A 76-year-old woman underwent minimally invasive aortic valve replacement, transcatheter lumbar artery embolism and retroperitoneal tumor resection within a short period of time. After a series of procedures, the patient experienced sudden back pain, and computed tomography revealed an AAD Type B. Her back pain persisted; therefore, we performed TEVAR, and the post-operative course was uneventful. In this case, the relationship between AAD and treatment before AAD was unclear, but AAD should considered when performing treatments that may cause AAD.

A 5-kV pulse generator with a 100-kV/µs slew rate based on series-connected 1700-V SiC MOSFETs for electrical insulation tests

This study demonstrates a high-slew-rate 5-kV pulse generator for electrical insulation tests. Electrical equipment, such as electrical actuators and traction drive motors, are exposed to severe electrical stress because recent switching inverters have high-frequency outputs with high supply voltages using wide-bandgap power devices. For an advanced electrical insulation test, a high-voltage pulse generator is required with a high slew rate; however, such generators suffer from large switching noise, followed by measurement noise, such as ground voltage fluctuations and radiation noise, hindering the detection of partial discharge (PD) phenomena. In this study, we propose a 5-kV pulse generator based on series-connected 1700-V silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). Four 1700-V SiC MOSFETs are connected in series as a 5-kV SiC switching module, constituting a half-bridge configuration for the pulse generator. The obtained switching waveforms exhibit fast rise times of 48 ns under 5 kV and 6.2 ns under 400 V with a low voltage overshoot and ringing owing to superior device characteristics and reduced parasitic inductances. Because of the low switching noise, we detect a clear PD signal with a 1500-V pulse when using the fabricated pulse generator for a PD test of a twisted pair. The proposed pulse generator uses a hard switching configuration such that the pulse generator can vary the pulse width from 150 ns to DC and increase the switching pulse cycle beyond 1 MHz by changing the control signals of the SiC MOSFETs.

Feasibility of the AtriClip Pro Left Atrium Appendage Elimination Device via the Transverse Sinus in Minimally Invasive Mitral Valve Surgery

Background

Achieving external access to and manual occlusion of the left atrial appendage (LAA) during minimally invasive mitral valve surgery (MIMVS) through a small right thoracotomy is difficult. Occlusion of the LAA using an epicardial closure device seems quite useful compared to other surgical techniques.

Methods

Fourteen patients with atrial fibrillation underwent MIMVS with concomitant surgical occlusion of the LAA using double-layered endocardial closure stitches (n=6, endocardial suture group) or the AtriClip Pro closure device (n=8, AtriClip group) at our institution. The primary safety endpoint was any device-related adverse event, and the primary efficacy endpoint was successful complete occlusion of blood flow into the LAA as assessed by transthoracic echocardiography at hospital discharge. The primary efficacy endpoint for stroke reduction was the occurrence of ischemic or hemorrhagic neurologic events.

Results

All patients underwent LAA occlusion as scheduled. The cardiopulmonary bypass and aortic cross-clamp times in the endocardial suture group and the AtriClip group were 202±39 and 128±41 minutes, and 213±53 and 136±44 minutes, respectively (p=0.68, p=0.73). No patients in either group experienced any device-related serious adverse events, incomplete LAA occlusion, early postoperative stroke, or neurologic complication.

Conclusion

Epicardial LAA occlusion using the AtriClip Pro during MIMVS in patients with mitral valve disease and atrial fibrillation is a simple, safe, and effective adjunctive procedure.

The Potential of AFX Iliac Extension in Abdominal Aortic Aneurysms with High Iliac Tortuosity

Recently, endovascular aortic aneurysm repair (EVAR) is the most common surgery for abdominal aortic aneurysm (AAA). However, iliac limb complications of EVAR often cause problems in patients with high iliac tortuosity. There is no difference of rate of iliac limb complication among EVAR devices, such as Excluder, Endurant, and Zenith in high iliac tortuosity. But there has been not reported about AFX. We studied AFX iliac extension as it is the only stent graft with an endoskeletal framework. This study aimed to evaluate the AFX iliac extension patency in a case in vitro and to use it in seven cases of AAA with high iliac tortuosity. The silicon tube inserted in the AFX iliac extension was flexed at 30, 60, 90, and 120 degrees, and the lumen of the iliac extension was monitored using an underwater camera in the circulatory system. During the experiment, the Iwaki Bellows Pump (IWAKI CO., LTD., Tokyo, Japan) produced a pulsating flow. We used this in seven patients with AAA high iliac tortuosity cases between November 2018 and May 2019. If the silicon tube inserted in the AFX iliac extension was flexed at 60 and 120 degrees, the stent protruded into the lumen. However, the graft was dilated at all degrees. All seven patients with AFX iliac extension had no complications and a patent iliac artery. The AFX iliac extension can reduce iliac limb complications in cases of high iliac tortuosity.

A simplified isolation technique for atherosclerotic aortic arch aneurysms surgery

The isolation technique is a useful adjunct that prevents atherosclerotic embolism in the brain when the aneurysm is filled with a massive hematoma or 'shaggy aorta'. But the technique is not widespread because of the difficulty in performing the cannulation. We modified this technique by simplifying the cannulation procedure using a puncture method with aortic root cannulas.

Descending aortic transection for recurrence of a pseudoaneurysm previously treated with a stent graft after extra-anatomical bypass for aortic coarctation: a case report

Background

In adult patients with primary or recurrent coarctation of the aorta (CoA), extra-anatomic bypass grafting (EABG) has been widely used as a surgical treatment option. However, there have been few reports on pseudoaneurysms (PAs) of the distal anastomotic sites after extra-anatomic bypass for CoA.

Case presentation

A 51-year-old man with hemoptysis was transferred to our hospital. Twenty years ago, he had undergone EABG from the ascending to the descending aorta (ascending-to-descending EABG) for CoA with right aortic arch. Eight years ago, he underwent thoracic endovascular aortic repair (TEVAR) for the ruptured PA on the distal anastomotic site of the EABG. Contrast-enhanced computed tomography scans revealed recurrent ruptured PA on the distal anastomotic site of the EABG. Therefore, we decided to replace the descending aorta, followed by end-to-side anastomosis of the EABG to the replaced descending aorta. However, due to massive adhesion of the lung to the EABG and PA, we performed transection of the descending aorta to decompress the PA. The postoperative course was uneventful, and the patient is doing well 5 months after surgery.

Conclusions

Aortic transection between the CoA and the distal anastomosis site may be a useful additional procedure in patients previously treated with TEVAR for PAs in the distal anastomosis site after EABG.

Surface Localization of the Dineutron in ^{11}Li

The formation of a dineutron in the ^{11}Li nucleus is found to be localized to the surface region. The experiment measured the intrinsic momentum of the struck neutron in ^{11}Li via the (p,pn) knockout reaction at 246  MeV/nucleon. The correlation angle between the two neutrons is, for the first time, measured as a function of the intrinsic neutron momentum. A comparison with reaction calculations reveals the localization of the dineutron at r∼3.6  fm. The results also support the density dependence of dineutron formation as deduced from Hartree-Fock-Bogoliubov calculations for nuclear matter.

Clinical implications of coronary artery morphology of patients with ischemia and non-obstructive coronary artery disease (INOCA) -An intracoronary OCT study-

Introduction

Ischemia and non-obstructive coronary artery disease (INOCA), including microvascular spasm (MVS) and epicardial spasm, has recently attracted much attention, for which in vivo imaging evaluation for coronary artery morphology is warranted for better understanding of this disorder. Besides the improved diagnostic accuracy of optical coherence tomography (OCT) for coronary plaques, we have recently demonstrated its capability for in vivo visualization of coronary adventitial vasa vasorum (VV) and the enhanced VV formation in patients with epicardial spasm.

Purpose

We aimed to examine OCT-delineated morphological characteristics in patients with INOCA in vivo.

Methods

A total of 335 consecutive INOCA patients, who underwent pharmacological spasm provocation tests, lactate sampling, and OCT imaging over the entire length of the left anterior descending (LAD) coronary arteries, were enrolled at our institute over 68 months from April 2013. They were classified into 4 groups; control with non-cardiac chest pain, MVS, diffuse spasm (DS), or focal spasm (FS) (Fig. 1A). MVS was diagnosed when negative lactate extraction ratio (coronary orifice &lt; coronary sinus) was detected despite the absence of epicardial spasm during the spasm provocation test. DS was defined as epicardial spasm induced in more than 2 coronary segments in LAD, and FS as epicardial spasm in one segment. Quantitative analyses for adventitial inflammation and atherosclerotic changes were performed by calculating VV density and %area stenosis (AS) on OCT (Fig. 1B, E). Furthermore, index of microcirculatory resistance (IMR), a marker of microvascular disorder with a cut-off value of ≥25, was measured during intravenous infusion of adenosine, which was then correlated with VV densities in the MVS and DS groups. Coronary plaque with a necrotic core was classified as fibroatheroma (FA), and the number of OCT frames with internal VV (IVV) in the atheroma was counted.

Results

VV density was significantly higher in MVS as compared with the controls (Fig. 1B). DS was most prevalent in INOCA (Fig. 1A) with highest VV density (Fig. 1B). Patients with IMR≥25 were predominantly distributed with a gradual increase in the MVS, DS, and FS groups, but none in the controls (Fig. 1C). Importantly, there was a significant positive correlation between VV densities and IMR in the MVS and DS groups (Fig. 1D). In addition, FS had the largest plaque size and showed the highest prevalence of FA and IVV (Fig. 1E–G).

Conclusions

These results indicate that MVS and DS are characterized by vasomotion abnormalities associated with adventitial inflammation and microvascular disorder, while FS by vulnerable atherosclerotic phenotype, suggesting that OCT may be useful for screening high-risk populations in INOCA.

Figure 1

Funding Acknowledgement

Type of funding source: None

Chloroplast Autophagy and Ubiquitination Combine to Manage Oxidative Damage and Starvation Responses

Autophagy and the ubiquitin-proteasome system are the major degradation processes for intracellular components in eukaryotes. Although ubiquitination acts as a signal inducing organelle-targeting autophagy, the interaction between ubiquitination and autophagy in chloroplast turnover has not been addressed. In this study, we found that two chloroplast-associated E3 enzymes, SUPPRESSOR OF PPI1 LOCUS1 and PLANT U-BOX4 (PUB4), are not necessary for the induction of either piecemeal autophagy of chloroplast stroma or chlorophagy of whole damaged chloroplasts in Arabidopsis (Arabidopsis thaliana). Double mutations of an autophagy gene and PUB4 caused synergistic phenotypes relative to single mutations. The double mutants developed accelerated leaf chlorosis linked to the overaccumulation of reactive oxygen species during senescence and had reduced seed production. Biochemical detection of ubiquitinated proteins indicated that both autophagy and PUB4-associated ubiquitination contributed to protein degradation in the senescing leaves. Furthermore, the double mutants had enhanced susceptibility to carbon or nitrogen starvation relative to single mutants. Together, these results indicate that autophagy and chloroplast-associated E3s cooperate for protein turnover, management of reactive oxygen species accumulation, and adaptation to starvation.

[Degenerated Monocusp Valve Complicated with Infective Endocarditis after Total Correction of Tetralogy of Fallot;Report of a Case]

There have been few reports about degenerated monocusp-valve patches, which were used for right ventricular outflow tract( RVOT) reconstruction with complications of infective endocarditis after total correction of tetralogy of Fallot( TOF).A 44-year-old male patient, who had a total correction of TOF using Monocusp Valved Outflow Patch (MVOP) 34 years previous, was admitted for heart failure with aortic regurgitation. An echocardiographic study showed an infective endocarditis with vegetations, attached to the aortic valve and the monocusp-valve outflow patch. The aortic valve was replaced with a mechanical prosthesis and the pulmonary valve was replaced with a biological prosthesis. RVOT was reconstructed using a bovine pericardial patch. The explanted monocusp-valve was deteriorated and heavily calcified. The postoperative course was uneventful. The patient was discharged and returned to his preoperative lifestyle 36 days after the redo surgery.

92Transcatheter aortic valve implantation improves cerebral blood flow and cognitive function in elderly patients with aortic stenosis - Brain perfusion SPECT imaging study

Background

Cognitive impairment and depression are commonly noted in elderly frail patients with severe aortic stenosis (AS). However, their mechanisms and reversibility after treatment remain remain to be examined.

Purpose

In this study, we examined whether transcatheter aortic valve implantation (TAVI) increases cerebral blood flow (CBF) in cognitive/emotional brain areas, such as the hippocampus, in the elderly patients with severe AS.

Methods

We examined consecutive 15 right-handed patients with severe AS who were eligible for TAVI (median age 83.2 years, 12 (80%) women). We evaluated the following assessments both at baseline and 3 months after TAVI. Frailty was evaluated based on Fried scale, which consists of 5 items, including gait speed, cognitive function, weight loss, exhaustion, and inactivity. Frail and pre-frail were defined as greater than 3 and 1∼2 in the scale, respectively. Cognitive and emotional status were evaluated with Logical Memory (LM) II, Mini Mental State Examination (MMSE), and geriatric depression scale (GDS). Lower LM II (less than 4 points) and MMSE (less than 24 points) and higher GDS (more than 6 points) indicate worse memory, general cognitive function, and depressive symptoms, respectively. CBF images were recorded with 99mTc single-photon emission computed tomography and were analyzed using SPM12. Briefly, CBF images were firstly normalized to the standard Montreal Neurological Institute space. Then, a voxel-wise parametric analysis was conducted between normalized CBF images at baseline and those after TAVI (P<0.005 at each voxel). Continuous variables were presented as mean ± standard error (SE). Normality was assessed using the Shapiro-Wilk test. Continuous variables were compared with the use of paired t test. Linear mixed-model analysis was performed to evaluate changes in neuropsychological tests and CBF over time.

Results

In the present study, all patients were not robust but pre-frail (47.3%) or frail (53.7%). LM II score was significantly improved at 3 months after TAVI compared with baseline (baseline, 8.7 vs. 3 months, 13.8, P<0.01) (Figure A), whereas no significant changes in MMSE or GDS scores were noted (baseline, 24.6 vs. 3 months, 25.2 for MMSE; baseline, 4.3 vs. 3 months, 4.2 for GDS). Importantly, although no patients showed clinical symptoms or signs for transient ischemic attack or stroke after TAVI, CBF in the local regions, including the right hippocampus, was significantly increased after TAVI compared with baseline (P<0.005 at each voxel) (green arrowheads) (Figure B). Furthermore, CBF in the right hippocampus were positively correlated with LM II scores (P=0.017) (Figure C).

Figure 1

Conclusions

These results provide the first evidence that TAVI improves cerebral perfusion (especially that in the hippocampus) and cognitive functions in elderly patients with severe AS.

P3575Clinical importance of fractional flow reserve in patients with organic coronary stenosis and vasospastic angina

Background

Vasospastic angina (VSA), which is one of the important functional cardiac disorders, may also play a role in the pathogenesis of atherosclerosis. Conversely, organic coronary stenosis is also known as an independent predictor for poor clinical outcomes in VSA patients. Although VSA patients have a variable degree of organic coronary stenosis in clinical setting, the functional importance of organic stenosis in those patients remains to be elucidated.

Purpose

The aim of this study was to examine the clinical importance and prognostic impact of fractional flow reserve (FFR) in patients with VSA and organic coronary stenosis.

Methods

We enrolled 236 consecutive patients with suspected vasospastic angina who underwent acetylcholine provocation test for coronary spasm (M/F 148/88, 63.6±12.0 [SD] yrs.). Among them, 175 patients (74.1%) were diagnosed as having VSA, while the remaining non-VSA patients were regarded as controls (Group-C, n=61). We divided the VSA patients into 3 groups based on angiographical findings and FFR values; VSA with no organic stenosis (>50% luminal stenosis) (Group-N, n=110), organic stenosis and high FFR (≥0.80) (Group-H, FFR 0.87±0.05, n=36), and organic stenosis and low FFR (<0.80) (Group-L, FFR 0.71±0.07, n=29). We evaluated the incidence of major adverse cardiovascular events (MACE), including cardiovascular death (CVD), non-fatal myocardial infarction (MI), urgent percutaneous coronary intervention (PCI), and hospitalization due to unstable angina pectoris (UAP) during the median follow-up period of 656 days.

Results

The groups with organic stenosis (Groups H and L) were characterized by higher prevalence of diabetes mellitus (Group-C/N/H/L, 23.0/20.9/44.4/34.5%, P=0.03) and dyslipidemia (Group-C/N/H/L, 37.7/39.1/50.0/65.5%, P=0.03) as compared with Group-C. After provocation test, all VSA patients received calcium channel blockers (CCBs). In addition, 20 days (median) after provocation test, 26 patients (92.9%) in Group-L underwent elective PCI with coronary stents, while no patient underwent PCI in Groups N or H. The incidence of MACE during follow-up was significantly higher in Group-L (Group-C/N/H/L; 1.6/3.6/5.6/27.6%, log-rank P<0.001), whereas clinical outcomes were comparable among the remaining 3 groups (Figure). Importantly, all 8 patients with MACE in Group-L had poor outcomes (CVD/MI/urgent PCI/UAP; 2/1/3/2) despite complete revascularization and the prevention of coronary spasm with CCBs, indicating that they might be resistant to standard contemporary therapies. They were characterized by less frequent use of angiotensin convert enzyme inhibitor (0 vs. 47.6%, P=0.02) and higher prevalence of multi-vessel organic lesions (37.5 vs. 4.8%, P=0.052) compared with those without MACE.

Figure 1

Conclusions

These results provide the first evidence that evaluation of coronary functional abnormalities with FFR is useful for making therapeutic strategies in VSA patients with organic coronary stenosis.

P4158Marked impairment of endothelium-dependent digital vasodilatations in patients with microvascular angina compared with those with vasospastic angina

Background/Introduction

Nitric oxide (NO) and endothelium-dependent hyperpolarization (EDH) factor are the major endothelium-derived relaxing factors. NO plays an important role in conduit arteries, while the importance of EDH factor increases as the vessel size decrease in patients with microvascular angina (MVA) compared with those with vasospastic angina (VSA) remains to be fully elucidated.

Purpose

We evaluated the roles of NO and EDH factor in conduit (brachial) arteries and resistance (digital) arteries of the patients with MVA, VSA and comorbid MVA+VSA patients.

Methods

We enrolled 39 patients who underwent diagnostic cardiac catheterization and divided them into 3 groups based on acetylcholine (ACh) provocation test, index of microcirculation resistance (IMR), and coronary flow reserve (CFR); MVA (N=9, mean age 59.9±3.5 years), VSA (N=12, mean age 61.3±1.8 years), and comorbid MVA+VSA (N=18, mean age 64.0±2.2 years). Endothelium-dependent brachial and digital vasodilatations in response to intra-arterial infusion of bradykinin (BK, 25, 50, and 100 ng/min for 2 min) were simultaneously measured by ultrasonography and peripheral arterial tonometry, respectively. Measurements were repeated after oral administration of aspirin (486 mg) and intra-arterial infusion of NG-monomethyl-L-arginine (L-NMMA, 8μmol/min for 5 min) in order to inhibit the effects of vasodilator prostaglandins and NO, respectively. Finally, endothelium-independent brachial and digital vasodilatations in response to sublingual nitroglycerin (NTG, 0.3 mg) were measured in the same manner.

Results

In the brachial artery, dose-dependent vasodilatations to BK were comparable among the 3 groups, and L-NMMA equally attenuated the responses to BK (Figure 1). Endothelium-independent brachial vasodilatation in response to NTG was also comparable among the 3 groups. Surprisingly, dose-dependent digital vasodilatations to BK were almost absent in MVA patients compared with VSA or comorbid MVA+VSA group (Figure 2). Furthermore, the digital vasodilatations were unaffected by L-NMMA in VSA group, but were significantly reduced in comorbid MVA+VSA group (VSA, 16.8±15.1% vs. MVA+VSA, −0.23±6.2%, P<0.05), suggesting reduced EDH and compensatory role of NO in the latter group. In contrast, endothelium-independent digital vasodilatation in response to NTG was comparable among the 3 groups.

The main results of this study

Conclusions

These results provide the first evidence that endothelium-dependent digital vasodilatations (both NO and EDH factor) are markedly impaired in MVA patients compared with VSA or comorbid MVA+VSA patients, whereas the responses are comparable in the brachial artery among the 3 groups, suggesting the involvement of severe endothelial dysfunction in the pathogenesis of MVA.

2381Low-intensity pulsed ultrasound ameliorates DES-induced coronary adventitial inflammation and hyperconstricting responses in pigs in vivo - A novel non-invasive therapy for coronary inflammation

Background

We previously demonstrated that coronary adventitial inflammation plays important roles in the pathogenesis of coronary artery spasm, including drug-eluting stent (DES)-induced coronary hyperconstricting responses, in pigs and humans. Indeed, the coronary adventitia has recently attracted much attention as the important site for vascular inflammation. However, a direct therapeutic approach to the coronary adventitia remains to be developed. We have developed a non-invasive low-intensity pulsed ultrasound (LIPUS) therapy for angina, which exerts anti-inflammatory effects through improved coronary microcirculation.

Purpose

In this study, we aimed to examine whether our LIPUS therapy ameliorates DES-induced coronary hyperconstricting responses in pigs in vivo, and if so, what mechanisms are involved.

Methods

An everolimus-eluting stent (EES) was implanted into the left anterior descending (LAD) coronary artery in normal male pigs. They were randomly assigned to the LIPUS or the sham therapy groups. After EES implantation, in the LIPUS group, LIPUS (32 cycles, 193 mW/cm2) was applied to the heart at 3 different levels (proximal and distal stent edges and middle portion of the stent) through X-ray for 20 min at each level for every other day for 2 weeks (6 days in total) (Figs. 1A, 1B). The sham therapy group was treated in the same manner but without LIPUS. At 4 weeks after the procedure, we performed coronary angiography to examine coronary vasoconstricting responses to intracoronary serotonin in vivo. Finally, stented coronary vessels were harvested for immunohistochemistry of vasa vasorum, lymphatic vessels (LYVE-1), sympathetic nerve fibers (SNF), vascular inflammation (macrophages and IL-1β expression), Rho-kinase expression and activity as evaluated by phosphorylated myosin phosphatase target subunit-1 (pMYPT-1).

Results

Coronary vasoconstricting responses to intracoronary serotonin were significantly enhanced in the sham therapy group but were significantly suppressed in the LIPUS group at the DES edges in the LAD, whereas those responses were comparable at the non-DES implanted segments in the left circumflex (LCx) coronary arteries between the 2 groups. (Figs. 1C, 1D). Furthermore, in vivo lymph transport speed was significantly faster in the LIPUS group than in sham group (Figs. 1E–1G). Histological analysis showed that except vasa vasorum formation, the number of lymphatic vessels, adventitial inflammatory cells infiltration, Rho-kinase expression and activity were all significantly enhanced in the sham therapy group and were significantly suppressed in the LIPUS group (Figs. 1G–1K).

Figure 1

Conclusion

We were able to develop a non-invasive LIPUS therapy for coronary functional abnormalities caused by chronic adventitial inflammation in pigs in vivo, for which multiple beneficial effects appear to be involved (Fig. 1L).

3332Exercise training ameliorates vasodilator capacity of coronary microvessels in patients with vasospastic angina - A new therapeutic approach for the coronary functional disorder

Background

We have recently demonstrated that coronary vasospasm could develop in both epicardial coronary arteries and intramuscular coronary microvessels in patients with vasospastic angina (VSA). However, it remains to be examined whether vasodilator capacity of coronary microvessels is impaired in VSA patients and if so, whether exercise training could ameliorate vasodilator capacity of coronary microvessels on the top of calcium channel blockers. The effectiveness of exercise training is established for organic coronary artery disease but remained to be examined for VSA.

Purpose

We thus examined whether vasodilator capacity of coronary microvessels is impaired in VSA patients without organic coronary stenosis using an adenosine-stress dynamic computed tomography perfusion (CTP) that can measure absolute value of myocardial blood flow (MBF). We also examined whether exercise training ameliorates not only vasodilator capacity of coronary microvessels but also exercise capacity and frequency of angina attack.

Methods

In the first protocol, we measured MBF using CTP in consecutive 32 VSA patients with acetylcholine-induced diffuse coronary spasm in the left anterior descending coronary arteries (LAD) and 12 non-VSA controls. In the second protocol, we conducted a randomized controlled trial (RCT; Exercise VSA trial, UMIN: ehz745.008423996), where 20 VSA patients were randomly assigned to either exercise group (Ex group: supervised exercise training session for 30-min using bicycle ergometer, once/week at the hospital and more than 3 times/week at home) or non-exercise group (Non-Ex group) (n=10 each) (Figure A). Before and 3 months after exercise training, we measured MBF with adenosine-stress dynamic CTP and peak VO2 by cardiopulmonary exercise tests, and also assessed angina attack with Seattle Angina Questionnaire (SAQ).

Results

In the first protocol, CTP showed that adenosine-stress MBF was significantly decreased in the VSA group compared with the non-VSA group (VSA, 137.2±6.6 vs. Non-VSA, 174.4±10.7 ml/100g/min, P<0.01) (Figure B), although patient characteristics were comparable between the 2 groups. In the second protocol, exercise training was performed safely in all patients, and RCT showed that MBF was significantly increased in the Ex group compared with the non-Ex group (Figures C, D), although patient characteristics were also comparable between the 2 groups. Furthermore, peak VO2 was significantly increased in the Ex group compared with the non-Ex group (Figure E), and frequency of angina was significantly decreased in the Ex group compared with the non-Ex group (Figure F). Finally, there was a significant positive correlation between the extents of the changes in peak VO2 and the SAQ score for angina frequency in the Ex group (P<0.01, R=0.67).

Figures

Conclusions

These results provide the first evidence that vasodilator capacity of coronary microvessels is impaired in VSA patients, which can be ameliorated by exercise training.

P6166Radiomics-based machine learning versus histogram analysis and visual assessment to identify advanced atherosclerotic lesions on coronary computed tomography angiography

Background

Currently used coronary CT angiography (CTA) plaque classification and histogram-based methods have limited accuracy to identify advanced atherosclerotic lesions. Radiomics-based machine learning (ML) could provide a more robust tool to identify high-risk plaques.

Purpose

Our objective was to compare the diagnostic performance of radiomics-based ML against histogram-based methods and visual assessment of ex-vivo coronary CTA cross-sections to identify advanced atherosclerotic lesions as defined by histology.

Methods

Overall, 21 coronaries of seven hearts were imaged ex vivo with coronary CTA. From 95 coronary plaques 611 histological cross-sections were obtained and classified based-on the modified American Heart Association scheme. Histology cross-sections were considered advanced atherosclerotic lesions if early, late fibroatheroma or thin-cap atheroma was present. Corresponding coronary CTA cross-section were co-registered and classified into homogenous, heterogeneous, napkin-ring sign plaques based on plaque attenuation pattern. Area of low attenuation (<30HU) and average CT number was quantified. In total, 1919 radiomic parameters describing the spatial complexity and heterogeneity of the lesions were calculated in each coronary CTA cross-section. Eight different radiomics-based ML models were trained on randomly selected cross-sections (training set: 75% of the cross-sections) to identify advanced atherosclerotic lesions. Plaque attenuation pattern, histogram-based methods and the best ML model were compared on the remaining 25% of the data (test-set) using area under the receiver operating characteristic curves (AUC) to identify advanced atherosclerotic lesions using histology as a reference.

Results

After excluding sections with heavy calcium (n=32) and no visible atherosclerotic plaque on CTA (n=134), we analyzed 445 cross-sections. Based on visual assessment, 46.5% of the cross-sections were homogeneous (207/445), 44.9% heterogeneous (200/445) and 8.6% were with napkin-ring sign (38/445). Radiomics-based ML model incorporating 13 parameters significantly outperformed visual assessment, area of low attenuation and average CT number to identify advanced lesions (AUC: 0.73 vs. 0.65 vs. 0.55 vs. 0.53; respectively; p<0.05 for all).

Conclusions

Radiomics-based ML analysis may be able to improve the discriminatory power of CTA to identify high-risk atherosclerotic lesions.

P4156Coexistence and prognostic impacts of epicardial and microvascular coronary dysfunctions in patients with chest pain and unobstructive coronary artery disease - Involvement of Rho-kinase activation

Background

Although the importance of coronary functional abnormalities has been emerging, including epicardial coronary spasm (vasospastic angina, VSA) and coronary microvascular dysfunction (CMD), comprehensive evaluation of the abnormalities in the same population remains to be examined.

Purpose

We examined the significance of coronary functional abnormalities in a comprehensive manner for both epicardial and microvascular coronary arteries in patients with chest pain and unobstructive coronary artery disease (CAD) as well as their prognostic impacts.

Methods and results

We prospectively enrolled 187 consecutive patients with suspected angina and unobstructive coronary arteries (M/F 113/74, 63.2±12.3 [SD] yrs.). We performed acetylcholine (ACh) provocation tests for coronary spasm, followed by functional tests for coronary microvascular function, including coronary flow reserve (CFR) and index of microcirculation resistance (IMR) during hyperemic state induced by intravenous adenosine. Among the 187 patients, ACh test identified 128 patients with VSA (68%). There was no significant difference in age, sex, or prevalence of traditional coronary risk factors between the non-VSA and the VSA groups. The median IMR value was significantly higher in the VSA group than in the non-VSA group [17.5 (12.0, 25.3) vs. 14.7 (10.7, 17.8), P=0.02], whereas CFR values were comparable between the 2 groups [2.51 (1.72, 3.35) vs. 2.66 (1.85, 3.64), P=0.34]. During the median follow-up period of 893 days, major adverse cardiac events (MACE), including cardiac death, non-fatal myocardial infarction, and hospitalization due to unstable angina pectoris, occurred in 10 patients (5.3%). Multivariable analysis revealed that IMR correlated with the incidence of MACE [hazard ratio (HR) (95% confidence interval), 1.05 (1.02–1.09), P=0.002] and receiver-operating characteristics curve analysis identified IMR of 18.0 as the optimal cut-off value for the incidence of cardiac events. When we divided the patients into the following 4 groups according to the cut-off value of IMR (>18) and the presence or absence of VSA; G1, IMR <18 without VSA (n=45); G2, IMR ≥18 without VSA (n=14); G3, IMR <18 with VSA (n=67); and G4, IMR ≥18 with VSA (n=61), the Kaplan-Meier survival analysis showed a significantly worse prognosis in G4 compared with other 3 groups (HR [95% CI] 6.23 [1.21–118.46], P=0.002) (Figure 1). Importantly, intracoronary administration of fasudil, a Rho-kinase inhibitor, significantly ameliorated IMR in G4 (P<0.0001) (Figure 2A), and %changes in IMR in response to intracoronary fasudil were more evident in G4 compared with other 3 groups (P<0.0001) (Figure 2B).

Conclusions

These results provide the first evidence that in patients with chest pain and unobstructive CAD, epicardial coronary spasm and increased microvascular resistance are frequently coexisted with worse long-term prognosis, for which Rho-kinase activationmay be involved.

[Mitral Valve Repair Using a New Artificial Ring which Enables to Decide the Length of Artificial Chordae]

Recently, mitral valve repair has been the mainstream of the operation for the treatment of mitral valve regurgitation. In particular, chorda reconstruction with artificial chordae is useful for the anterior leaflet. However, there has been no established method determining the length of chordae. In this report, we performed mitral valve repair using Memo 3D ReChord ring which enables to decide the length of chordae more easily. It is based on the concept of folding leaflet technique by Garcia et al. We used this ring in 7 patients (of which 2 were reoperation) in our institution. There was no postoperative death nor complication. Postoperative transthoracic echocardiography showed class 0~ Ⅰ mitral valve regurgitation in each case at discharge. This ring helps to make the repair more reproducible and we consider that it enables to decide the length of chordae more easily even in reoperative cases.