A case of hypervirulent K1-ST23 Klebsiella pneumoniae endocarditis and papillary muscle rupture secondary to multiple site abscesses.

Hypervirulent Klebsiella pneumoniae (hvKP) causes multisite infections and abscesses. However, endocarditis is a rare presentation of hvKP infection. Herein, we report a case of K. pneumoniae native valve infective endocarditis secondary to community-acquired liver and prostate abscesses. The patient developed papillary muscle rupture, leading to mitral regurgitation, and underwent emergent mitral valve replacement. The diagnosis of endocarditis was confirmed microbiologically and histologically. The causative strain belonged to the hypermucoid K1 capsular genotype and possessed the rmpA gene. The genome sequence was deposited in GenBank under the accession number JAQZBZ000000000.

Prevalence of bleeding events in real-world Japanese registry for Percutaneous Ventricular Assist Device.

PURPOSE: Bleeding complication is a critical risk factor for outcomes of acute heart failure patients requiring mechanical circulatory support (MCS), including percutaneous catheter-type heart pumps (Impella). The Japanese registry for Percutaneous Ventricular Assist Device (J-PVAD) is an ongoing, large-scale, real-world registry to characterize Japanese patients requiring Impella. Here we analyzed bleeding complication profiles in patients who received Impella. METHODS: All consecutive Japanese patients who received Impella from October 2017 to January 2020 were enrolled. The 30-day survival and bleeding complications were analyzed. RESULTS: A total of 1344 patients were included: 653 patients received Impella alone, 685 patients received a combination of veno-arterial extracorporeal membrane oxygenation and Impella (ECPELLA), and 6 patients had failed Impella delivery. Overall 30-day survival was 67.0%, with Impella alone at 81.9% and ECPELLA at 52.7%. Overall bleeding/hematoma adverse events with a relation or not-excluded relation to Impella was 6.92%. Among them, the rates of hematoma and bleeding from medical device access sites were 1.41% and 4.09%, respectively. There was no difference between etiologies for these events. CONCLUSION: This study represents the first 3-year survival and the safety profile focused on bleeding adverse events from the J-PVAD registry. The results show that the real-world frequency of bleeding adverse events for patients who received Impella was an expected range from previous reports, and future real-world studies should aim to expand this data set to improve outcomes and adverse events.

Impact of the coronavirus disease 2019 pandemic on 20 representative surgical procedures in Japan based on the National Clinical Database: annual surveillance of 2021 by the Japan Surgical Society.

PURPOSE: The volume of surgical services has significantly reduced globally due to the coronavirus disease 2019 (COVID-19) pandemic. This study evaluated the level of recovery in terms of the number of operations performed in Japan in 2021, based on nationwide periodic surveillance. METHODS: Information on the weekly and annual volumes of 20 representative procedures in 6 surgical subspecialties in 2021 was extracted from the National Clinical Database. Statistical data for 2018 and 2019 (pre-pandemic era) were compared with those for 2020. Data on waves of infection, peak period, and high-prevalence areas (13 of 47 prefectures) were analyzed individually. RESULTS: The volumes of the 10 procedures, including gastrectomy, hepatectomy, valve replacement and valve plasty, coronary artery bypass grafting, infrarenal abdominal aorta replacement, ventricular septal defect closure, lung lobectomy, inguinal hernia repair (age < 16 years old), and appendectomy (age < 16 years old), did not reach 95% of that in the pre-pandemic era. The most striking decline in the surgical volume of these 10 procedures was observed during the peak period of wave 5 in high-prevalence areas. CONCLUSION: This near-complete enumeration survey identified the polarization of 20 representative procedures in terms of resumption of surgical service after the pandemic.

[Surgical Replacement of Descending Aorta for Adult Aortic Coarctation by Using Three-dimensional Computer Graphics Reconstruction].

Aortic coarctation is diagnosed in approximately 5% of adult patients with congenital heart disease and is commonly diagnosed through the close examination of hypertension. Various surgical strategies for adult coarctation have been recently reported. Generally, aortic replacement may require blood transfusion in case of injury of the well-developed collateral vessels. Therefore, in order to secure an operative safety, we preoperatively used a medical image viewer to identify the abnormal vessels by three-dimensional computer graphics (3DCG) reconstruction. A 34-year-old male patient was referred to our hospital with hypertension and low ankle-brachial pressure index( ABI). Chest computed tomography( CT) scan showed aortic coarctation and development of abnormal collateral vessels. Descending aorta was replaced via a left third-fourth intercostal thoracotomy under partial extracorporeal circulation. As the image viewer depicted, anatomical abnormality of the collateral vessels was identified precisely, and surgically treated without any injury. The patient was discharged 10 days postoperatively without transfusion and with a normalized ABI.

Effect of renal function under left ventricular assist device support on the cardiac function and clinical events after heart transplantation.

AIM: We investigated the effects of pre-transplantation renal dysfunction under left ventricular assisted device (LVAD) support on post-transplantation cardiac function, and patient prognosis after heart transplantation (HTx). METHOD: All patients who were bridged by LVAD and underwent HTx at our hospital between 2007 and 2022 were included in this study. Patients were classified into two groups based on estimated glomerular filtration rate (eGFR) before HTx: renal dysfunction (RD) group (eGFR < 60 mL/min/1.73 m2 ) and non-renal dysfunction (NRD) group. RESULT: A total of 132 patients were analyzed, of whom 48 were classified into the RD group and 84 into the NRD group (RD group, 47.9 ± 10.1 years; NRD group, 38.4 ± 11.9 years, p < .0001). Under LVAD support before HTx, the RD group tended to have a history of right ventricular failure (RD group, nine (19%); NRD group, seven (8%); p = .098). After HTx, the echocardiographic parameters did not differ between the two groups in the long term. Furthermore, more concise hemodynamic parameters, exemplified by right heart catheterization, were not significantly different between the two groups. Regarding graft rejection, no significant differences were found in acute cellular rejection and cardiac allograft vasculopathy following HTx. In contrast, patients with RD before HTx had significantly increased mortality in the chronic phase after HTx and initiation of maintenance dialysis, without any overt changes in cardiac function. CONCLUSION: Pre-transplantation renal dysfunction under LVAD support significantly affected clinical course after HTx without any overt changes in graft cardiac function.

Clinical and Economic Evaluation of Impella Treatment for Fulminant Myocarditis　- A Preliminary Retrospective Cohort Study in Japan.

BACKGROUND: Fulminant myocarditis (FM) is rare but has an extremely poor prognosis. Impella, a catheter-based heart pump, is a new therapeutic strategy, but reports regarding its health economics are lacking.Methods and Results: This retrospective cohort study compared Impella treatment (Group I) with existing treatments (Group E) using medical data collected from October 2017 to September 2021, with a 1-year analysis period. Cost-effectiveness indices were life-years (LY; effect index) and medical fee amount (cost index). Results were validated using probabilistic sensitivity analysis. The incremental cost-effectiveness ratio (ICER) was calculated using quality-adjusted LY (QALY) and medical costs. Each group included 7 patients, and more than half (57.1%) received combined Impella plus extracorporeal membrane oxygenation. There was no significant difference between Groups I and E in 1-year mortality rates (28.6% vs. 57.1%, respectively) or LY (mean [±SD] 163.1±128.3 vs. 107.8±127.3 days, respectively), but mortality risk was significantly lower in Group I than Group E (95% confidence interval 0.02-0.96; P<0.05). Compared with Group E, Group I had higher total costs (9,270,597±4,121,875 vs. 6,397,466±3,801,364 JPY/year; P=0.20) and higher cost-effectiveness (32,443,987±14,742,966 vs. 92,637,756±98,225,604 JPY/LY; P=0.74), which was confirmed in the sensitivity analysis. ICER probability distribution showed 23.2% and 51.5% reductions below 5 million and 10 million JPY/QALY, respectively. CONCLUSIONS: Impella treatment is more cost-effective than conventional FM treatments. Large-scale studies are needed to validate the added effects and increasing costs.

Short-Term Outcomes of Impella Support in Japanese Patients With Cardiogenic Shock Due to Acute Myocardial Infarction　- Japanese Registry for Percutaneous Ventricular Assist Device (J-PVAD).

BACKGROUND: The Impella®percutaneous left ventricular assist device has been available in Japan since 2017. This is the first large-scale registry study to analyze the efficacy and safety of Impella in Japanese patients with acute myocardial infarction with cardiogenic shock (AMICS).Methods and Results: The Japanese registry for Percutaneous Ventricular Assist Device (J-PVAD) has registered all consecutive Japanese patients treated with Impella. We extracted data for 593 AMICS patients from J-PVAD and analyzed 30-day survival and safety profiles. Overall 30-day survival was 63.1%. The 30-day survival of the Impella alone and Impella plus venoarterial extracorporeal membrane oxygenation (ECPELLA) groups was 80.9% and 45.7%, respectively. The Impella alone group was older and had a lower rate of cardiac arrest, milder consciousness disturbance, less inotrope use, lower serum lactate concentrations, higher B-type natriuretic peptide concentrations, and higher left ventricular ejection fraction (LVEF) than the ECPELLA group. Cox regression analysis revealed that older age and comorbid renal disturbance were common risk factors affecting 30-day mortality in both groups. Major adverse events were hemolysis (10.8%), hemorrhage/hematoma (7.6%), peripheral ischemia (4.4%), stroke (1.3%), and thrombosis (0.7%). LVEF improved in both groups during support. CONCLUSIONS: AMICS treatment with Impella showed favorable 30-day survival and safety profiles. The survival rate of patients treated with Impella alone was particularly high. Further studies are needed to improve outcomes of patients with ECPELLA support.

Novel Scoring System to Risk Stratify Patients Receiving Durable Left Ventricular Assist Device From J-MACS Registry Data.

BACKGROUND: Recently, destination therapy (DT) was approved in Japan, and patients ineligible for heart transplantation may now receive durable left ventricular assist devices (LVADs). Several conventional risk scores are available, but a risk score that is best to select optimal candidates for DT in the Japanese population remains unestablished.Methods and Results: A total of 1,287 patients who underwent durable LVAD implantation and were listed for the Japanese registry for Mechanically Assisted Circulatory Support (J-MACS) were eligible for inclusion. Finally, 494 patients were assigned to the derivation cohort and 487 patients were assigned to the validation cohort. According to the time-to-event analyses, J-MACS risk scores were newly constructed to predict 3-year mortality rate, consisting of age, history of cardiac surgery, serum creatinine level, and central venous pressure to pulmonary artery wedge pressure ratio >0.71. The J-MACS risk score had the highest predictability of 3-year death compared with other conventional scores in the validation cohort, including HeartMate II risk score and HeartMate 3 risk score. CONCLUSIONS: We constructed the J-MACS risk score to estimate 3-year mortality rate after durable LVAD implantation using large-scale multicenter Japanese data. The clinical utility of this scoring to guide the indication of DT should be validated in the next study.

Coronary microembolization sheep model by adjusting the number of microspheres based on coronary blood flow.

BACKGROUND: A heart failure (HF) model using coronary microembolization in large animals is indispensable for medical research. However, the heterogeneity of myocardial response to microembolization is a limitation. We hypothesized that adjusting the number of injected microspheres according to coronary blood flow could stabilize the severity of HF. This study aimed to evaluate the effect of microsphere injection based on the left coronary artery blood flow in an animal model. METHODS: Microembolization was induced by injecting different numbers of microspheres (polystyrene, diameter: 90 µm) into the left descending coronary artery of the two groups of sheep (400 and 600 times coronary blood flow [ml/min]). Hemodynamic parameters, the pressure-volume loop of the left ventricle, and echocardiography findings were examined at 0.5, 1.5, 3.5, and 6.5 h after microembolization. RESULTS: End-diastolic pressure and normalized heart rate increased over time, and were significantly higher in 600 × coronary blood flow group than those in 400 × coronary blood flow group (p = 0.04 and p < 0.01, respectively). The maximum rate of left-ventricular pressure rise and normalized stroke volume decreased over time, and were significantly lower in 600 × coronary blood flow group than those in 400 × coronary blood flow group (p < 0.01 and p < 0.01, respectively). The number of microspheres per coronary blood flow was significantly correlated with the decrease in stroke volume and the maximum rate of left ventricular pressure rise in 6.5 h (r = 0.74, p = 0.01 and r = 0.71, p = 0.02, respectively). CONCLUSIONS: Adjusting the number of injected microspheres based on the coronary blood flow enabled the creation of HF models with different degrees of severity.

Prophylactic negative pressure wound therapy is not effective for preventing driveline infection following left ventricular assist device implantation.

BACKGROUND: Driveline infection (DLI) following left ventricular assist device (LVAD) implantation remains an unresolved problem. Negative pressure wound therapy (NPWT) promotes wound healing by applying negative pressure on the surface of the wound. Recently, the prophylactic application of NPWT to closed surgical incisions has decreased surgical site infections in various postsurgical settings. Therefore, we evaluated the efficacy and safety of prophylactic NPWT for preventing DLI in patients with LVAD implantation. METHODS: Prophylactic NPWT was provided to 50 patients who received continuous-flow LVADs as bridge-to-transplant therapy at our institution between May 2018 and October 2020 (NPWT group). The negative pressure dressing was applied immediately after surgery and retained on the driveline exit site for 7 days with a continuous application of -125 mm Hg negative pressure. The primary outcome was DLI within 1 year of LVAD implantation. We compared the rate of DLI incidence in the NPWT group with that in the historical control cohort (50 patients) treated with the standard dressing (SD) who received LVAD implantation between July 2015 and April 2018 (SD group). RESULTS: No severe complications were associated with the NPWT. During the follow-up period, DLI was diagnosed in 16 participants (32%) in the NPWT group and 21 participants (42%) in the SD group. The rates of DLI incidence and freedom from DLI did not differ between groups (p = 0.30 and p = 0.63). CONCLUSIONS: Prophylactic NPWT at the driveline exit site was safe following LVAD implantation. However, it did not significantly reduce the risk of DLI.

EVAHEART 2 with double cuff tipless inflow cannula is suitable for long-term support atrial switch operation in transposition of great arteries.

Implantation of continuous-flow left ventricular assist device in a narrow lumen is technically challenging to secure an optimal support. We experienced a patient with the transposition of the great arteries after the Senning procedure who was initially implanted with Jarvik 2000®. She presented with worsening heart failure symptoms 2 years after implanting Jarvik 2000®. We assumed that the inflow cannula was stuck in the highly developed trabeculae on the interventricular septum, which disturbed the VAD to maintain an expected support. After converting to the EVAHEART® 2, we successfully obtained an adequate inflow. We consider that the tipless cannula of EVAHEART® 2 is the most suitable when there is no sufficient room to place a conventional inflow cannula in the systemic ventricle.

Three-year experience of catheter-based micro-axial left ventricular assist device, Impella, in Japanese patients: the first interim analysis of Japan registry for percutaneous ventricular assist device (J-PVAD).

Catheter-based micro-axial ventricular assist device Impella® (Abiomed, Danvers, MA) has been used in Japanese patients with drug-refractory acute heart failure (AHF) since 2017. This is the first interim analysis of the ongoing Japan Registry for Percutaneous Ventricular Assist Device (J-PVAD) to investigate the safety and efficacy of Impella support. Between October 2017 and January 2020, 823 Japanese patients, who were treated with the Impella 2.5, CP, or 5.0 pump, were enrolled. The primary endpoints were safety profiles and cumulative 30-day survival. Among them, 44.8% of patients were acute myocardial infarction with cardiogenic shock. The Impella pumps were unable to implant in 4 patients. The Impella 2.5, CP, and 5.0 pumps were used in 72.4%, 6.2%, and 16.6%, respectively, and mean support duration was 8.1 ± 10.2 days. Combination use of Impella and venoarterial extracorporeal membrane oxygenation (VA-ECMO) was applied for 387 patients (47.3%). Pump stop occurred 22 patients (2.7%). Major adverse events included hemolysis (11.2%), hemorrhage/hematoma (6.1%), peripheral ischemia (1.6%), and stroke (1.6%). The overall 30-day survival was 62.2%. Survival of patients with single Impella support was significantly higher than patients with Impella combined with VA-ECMO support (81.1% vs 49.6%; p < 0.01), who had lower blood pressure, lower left ventricular ejection fraction, and higher degree of inotropic support. Results suggest that short-term outcome of Impella support for Japanese patients was favorable with acceptable safety profiles.

Successful Treatment with Letermovir in a Heart Transplant Recipient with UL97 Mutation Ganciclovir-Resistant Cytomegalovirus Colitis and Viremia.

Currently available anti-cytomegalovirus (CMV) agents are sometimes poorly tolerated, owing to their side effects. Letermovir is a novel anti-CMV drug that is only approved for CMV prophylaxis in hematopoietic stem cell transplant recipients, with fewer side effects. We report the case of a heart transplant recipient with UL97 mutation (L595F) ganciclovir-resistant cytomegalovirus colitis who was successfully treated with off-label use of letermovir. In treating CMV infection or disease with letermovir, a transient rise or lag in the clearance of CMV-DNA polymerase chain reaction levels has been observed. Our case suggests that CMV-pp65 antigenemia can be an additional marker of treatment efficacy.

[Aortic Root Replacement with Homograft].

Infectious endocarditis is a severe infectious disease in cardiovascular surgery fields. Appropriate antibiotics administration is the principle of treatment, while surgical intervention is required when there is intensive tissue destruction, refractory infection, or high risk of embolism. Usually, surgical risks of infectious endocarditis are rather high as preoperative general condition is often poor. Homografts, which have excellent anti-infective properties, become one of the graft options for infectious endocarditis. Fortunately, we are able to use homografs without so much obstacles thanks to the presence of a tissue bank in our hospital. We will report our strategy and clinical courses of aortic root replacement using homograft for infective endocarditis.

Effect of Diabetes Mellitus on Outcomes in Patients With Left Ventricular Assist Device　- Analysis of Data From a Japanese National Database.

BACKGROUND: The objective of this study is to investigate the effect of preoperative diabetes on all-cause mortality and major postoperative complications among patients with continuous-flow left ventricular assist device (LVAD) by using data from a national database.Methods and Results: The 545 study patients who underwent primary HeartMateII implantation between 2013 and 2019 were divided into 2 groups according to their diabetes mellitus (DM) status; patients with DM (n=116) and patients without DM (n=429). First, the on-device survival and incidence of adverse events were evaluated. Second, after adjusting for patients' backgrounds, the change of laboratory data in the 2 groups were compared. Overall, on-device survival at 1, 2, and 3 years was almost equivalent between the 2 groups; it was 95%, 94%, and 91% in patients without DM, and 93%, 91%m and 91% in patients with DM (P=0.468) The incidence of adverse events was similar between 2 groups of patients, except for driveline exit site infection in the adjusted cohort. Cox proportional hazards regression analysis revealed younger age (HR: 0.98 (95% confidence interval (CI): 0.97-0.99, P=0.001) and presence of DM (HR: 1.83 (95% CI: 1.14-2.88), P=0.016) as significant predictors of driveline infection. Laboratory findings revealed no differences between groups throughout the periods. CONCLUSIONS: The clinical results after LVAD implantation in DM patients were comparable with those in non-DM patients, except for the driveline exit site infection.

Impact of COVID-19 on living donor liver and kidney transplantation programs in Japan in 2020.

BACKGROUND: Although many transplant programs have been forced to suspend living donor transplants due to the emergence of coronavirus disease (COVID-19), there are relatively few real-time databases to assess center-level transplant activities. We aimed to delineate the actual impact of COVID-19 on living donor transplant programs and the resumption process in Japan. METHODS: In a nationwide survey, questionnaires were sent to 32 liver transplant programs that had performed at least more than one case of living donor liver transplantation in 2019 and 132 kidney transplant programs that had performed more than one living donor kidney transplantation in 2018. RESULTS: Thirty-one (96.9%) and 125 (94.7%) liver and kidney transplant programs responded, respectively. In the early pandemic period, 67.7% (21/31) of liver programs and 29.8% (37/125) of kidney programs were able to maintain transplant activities similar to those during the pre-pandemic period. After temporal suspension, 58.1% of kidney programs resumed their transplant activity after the number of local COVID-19 cases peaked. Establishing institutional COVID-19 screening, triage, and therapeutic management protocols was mandatory to resume transplant activity for 64.5% and 67.7% of liver and kidney programs, respectively. In the future wave of COVID-19, 67.7% of liver programs would be affected by institutional COVID-19 intensive care unit-bound patient numbers, and 55.7% of kidney programs would stop if hospital-acquired severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection spreads. CONCLUSIONS: THIS NATIONWIDE SURVEY REVEALED FOR THE FIRST TIME HOW LIVING DONOR LIVER AND KIDNEY: transplant programs changed in response to the COVID-19 pandemic in a country where living donor transplantations are predominant.

Association between left ventricular ejection fraction and mortality after Bentall procedure.

Root infection or dissection involving coronary artery frequently necessitates an emergent Bentall procedure, with low left ventricular ejection fraction (LVEF). In contrast, concerning an elective Bentall for aneurysm, surgeons should balance the risk and benefit of surgery, especially in low LVEF cases. We investigated the association between preoperative LVEF and outcomes after Bentall. We analyzed 98 patients undergoing Bentall between April 2000 and March 2020. The patients were stratified into three groups: (a) 65 with LVEF ≥ 60%, (b) 21 with LVEF 45 to < 60%, and (c) 12 with LVEF < 45%. Baseline characteristics, survivals, and major adverse cardiovascular events (MACE) were compared. To assess potential non-linear relationship between LVEF and mortality, cubic spline analysis was conducted. Median age was similar (a vs b vs c, 52 vs 50 vs 44). In all groups, elective root aneurysm was 50-60%, indicating the rest were complicated and sick. Operative mortality was the highest in group c (4.6% vs 9.5% vs 16.7%, p = 0.294). Survival and MACE-free rate were the worst in group c, though their 10-year survival was 40%. LVEF was an independent risk for mortality, and cubic spline analysis showed potential non-linear association between LVEF and mortality. Although LVEF is an independent predictor of mortality after Bentall, long-term survival was occasionally achieved in low LVEF cases. While surgeons should carefully balance the risk of low LVEF and the benefit of surgery in elective cases, we should perform a non-elective procedure as needed, even if LVEF is low.

Cost of postoperative complications of lower anterior resection for rectal cancer: a nationwide registry study of 15,187 patients.

PURPOSE: To assess the increase in hospital costs associated with postoperative complications after lower anterior resection (LAR) for rectal cancer. METHODS: The subjects of this retrospective analysis were patients who underwent elective LAR surgery between April, 2015 and March, 2017, collected from a Japanese nationwide gastroenterological surgery registry linked to hospital-based claims data. We evaluated total and category-specific hospitalization costs based on the level of postoperative complications categorized using the Clavien-Dindo (CD) classification. We assessed the relative increase in hospital costs, adjusting for preoperative factors and hospital case volume. RESULTS: We identified 15,187 patients (mean age 66.8) treated at 884 hospitals. Overall, 71.8% had no recorded complications, whereas 7.6%, 10.8%, 9.0%, 0.6%, and 0.2% had postoperative complications of CD grades I-V, respectively. The median (25th-75th percentiles) hospital costs were $17.3 K (16.1-19.3) for the no-complications group, and $19.1 K (17.3-22.2), $21.0 K (18.5-25.0), $27.4 K (22.4-33.9), $41.8 K (291-618), and $22.7 K (183-421) for the CD grades I-V complication groups, respectively. The multivariable model identified that complications of CD grades I-V were associated with 11%, 21%, 61%, 142%, and 70% increases in in-hospital costs compared with no complications. CONCLUSIONS: Postoperative complications and their severity are strongly associated with increased hospital costs and health-care resource utilization. Implementing strategies to prevent postoperative complications will improve patients' clinical outcomes and reduce hospital care costs substantially.

The impact of COVID-19 on surgical procedures in Japan: analysis of data from the National Clinical Database.

BACKGROUND AND PURPOSE: The spread of COVID-19 has restricted the delivery of standard medical care to surgical patients dramatically. Surgical triage is performed by considering the type of disease, its severity, the urgency for surgery, and the condition of the patient, in addition to the scale of infectious outbreaks in the region. The purpose of this study was to evaluate the impact of the COVID-19 pandemic on the number of surgical procedures performed and whether the effects were more prominent during certain periods of widespread infection and in the affected regions. METHODS: We selected 20 of the most common procedures from each surgical field and compared the weekly numbers of each operation performed in 2020 with the respective numbers in 2018 and 2019, as recorded in the National Clinical Database (NCD). The surgical status during the COVID-19 pandemic as well as the relationship between surgical volume and the degree of regional infection were analyzed extensively. RESULTS: The rate of decline in surgery was at most 10-15%. Although the numbers of most oncological and cardiovascular procedures decreased in 2020, there was no significant change in the numbers of pancreaticoduodenectomy and aortic replacement procedures performed in the same period. CONCLUSION: The numbers of most surgical procedures decreased in 2020 as a result of the COVID-19 pandemic; however, the precise impact of surgical triage on decrease in detection of disease warrants further investigation.

A Novel Knitted Polytetrafluoroethylene Patch for Cardiovascular Surgery.

Polytetrafluoroethylene (PTFE) is widely used in cardiovascular surgeries; however, postoperative complications such as thrombosis, calcification, and neointimal hyperplasia are yet to be resolved in patients. We developed two types of novel knitted PTFE patches and evaluated them using a swine model. Both patches were composed of knitted PTFE impregnated with micro-PTFE particles, and one of them was pressed after PTFE impregnation. Twenty micromini pigs were used in this study. After left lateral thoracotomy, the new patches (n = 8 for each type of patch) were implanted into the descending aorta and left atrium for the high- and low-pressure models, respectively. Clinically used expanded PTFE (ePTFE) patches were used as the control material (n = 4). The patches were explanted and histopathologically examined at 4, 12, and 24 weeks after implantation. A tensile test was also applied to the high-pressure model at 12 and 24 weeks. As a result, there was no significant difference noted in the tensile test, intimal hyperplasia thickness, or endothelialization among the three patches. In contrast, the degree of macrophage infiltration into the patches and the degree of macrophage, lymphocyte, and granulocyte infiltration outside the patches were lower in the new patches than in the control ePTFE. The degree of cellular infiltration outside new patches decreased over time. There were no significant differences between the two new patch types in these results. In conclusion, our novel knitted PTFE patch showed noninferiority in durability and intensity and less inflammatory responses than a clinically used ePTFE patch.