Predictors of 1-year outcome after cardiac re-transplantation: Machine learning analysis.

BACKGROUND: As cardiac re-transplantation is associated with inferior outcomes compared with primary transplantation, allocating scarce resources to appropriate re-transplant candidates is important. The aim of this study is to elucidate the factors associated with 1-year mortality in cardiac re-transplantation using the random forests algorithm for survival analysis. METHODS: We retrospectively reviewed the United Network for Organ Sharing registry and identified all adult (> 17 years old) recipients who underwent cardiac re-transplantation between January 2000 and March 2020. The random forest algorithm on Cox modeling was used to calculate the variable importance (VIMP) of independent variables for contributing to 1-year mortality. RESULTS: A total of 1294 patients underwent cardiac re-transplantation. Of these, 137 patients were re-transplanted within 1 year of their first transplant, while 1157 patients were re-transplanted more than 1 year after their first transplant. One-year mortality was significantly higher for patients receiving early transplantation compared with those receiving late transplantation (Early 40.6% vs. Late 13.6%, log-rank P < .001). Machine learning analysis showed that total bilirubin (> 2 mg/dl) (VIMP, 2.99%) was an independent predictor of 1-year mortality after early re-transplant. High BMI (> 30.0 kg/m2 ) (VIMP, 1.43%) and ventilator dependence (VIMP, 1.47%) were independent predictors of 1-year mortality for the late re-transplantation group. CONCLUSION: Machine learning showed that optimal 1-year survival following cardiac re-transplantation was significantly related to liver function in early re-transplantation, and to obesity and preoperative ventilator dependence in late re-transplantation.

Deep vein thrombosis and pulmonary embolism after heart transplantation.

INTRODUCTION: Venous thromboembolism (VTE), such as deep vein thrombosis (DVT) and pulmonary embolism (PE), is an important and serious postoperative complication after heart transplantation. We sought to characterize in-hospital VTE after heart transplantation and its association with clinical outcomes. METHOD: Adult (≧18 years) patients undergoing heart transplantation from 2015 to 2019 at our center were retrospectively reviewed. Post-transplant VTE was defined as newly diagnosed venous system thrombus by imaging studies. RESULTS: There were 254 patients. The cohort's median age was 55 years. A total of 61 patients were diagnosed with VTE, including one with right atrial thrombus, 54 with upper extremity DVT in which one patient subsequently developed PE, four with lower extremity DVT, and two with upper and lower extremity DVT. The cumulative incidence of VTE was 42% at 60-days of post heart transplant. Patients with VTE had longer hospital stay (P < .001), higher in-hospital mortality (P = .010), and worse 5-year survival (P = .009). On the multivariable Cox analysis, history of DVT/PE and intubation for more than 3 days were associated with an increased risk of in hospital VTE. CONCLUSION: The incidence of VTE in heart transplant recipients is high. Post-transplant surveillance, and appropriate preventive measures and treatment strategies after diagnosis are warranted.

Preoperative Left Ventricular Energy Loss in the Operating Theater Reflects Subjective Symptoms in Chronic Aortic Regurgitation.

BACKGROUND: There is currently no subjective, definitive evaluation method for therapeutic indication other than symptoms in aortic regurgitation. Energy loss, a novel parameter of cardiac workload, can be visualized and quantified using echocardiography vector flow mapping. The purpose of the present study was to evaluate whether energy loss in patients with chronic aortic regurgitation can quantify their subjective symptoms more clearly than other conventional metrics. METHODS: We studied 15 patients undergoing elective aortic valve surgery for aortic regurgitation. We divided the patients into symptomatic and asymptomatic groups using their admission records. We analyzed the mean energy loss in one cardiac cycle using transesophageal echocardiography during the preoperative period. The relationships between symptoms, energy loss, and other conventional metrics were statistically analyzed. RESULTS: There were seven and eight patients in the symptomatic and asymptomatic groups, respectively. The mean energy loss of one cardiac cycle was higher in the symptomatic group (121 mW/m [96-184]) than in the asymptomatic group (87 mW/m [80-103]) (p = 0.040), whereas the diastolic diameter was higher in the asymptomatic group (65 mm [59-78]) than in the symptomatic group (57 mm [51-57]) (p = 0.040). There was no significant difference between the symptomatic and asymptomatic groups in terms of other conventional metrics. CONCLUSIONS: An energy loss can quantify patients' subjective symptoms more clearly than other conventional metrics. The small sample size is the primary limitation of our study, further studies assessing larger cohort of patients are warranted to validate our findings.

Left Ventricular Assist Device Support-Induced Alteration of Mechanical Stress on Aortic Valve and Aortic Wall.

The aim of this study was to evaluate the fluid dynamics in the aortic valve and proximal aorta during continuous-flow left ventricular assist device (LVAD) support using epiaortic echocardiography and vector flow mapping technology. A total of 12 patients who underwent HeartMate 3 implantation between December 2018 and February 2020 were prospectively examined. The wall shear stress (WSS) on the ascending aorta, aortic root, and aortic valve was evaluated before and after LVAD implantation. The median age of the cohort was 62 years and 17% were women. The peak WSS on the ascending aorta (Pre 1.48 [0.86-1.69] [Pascal {Pa}] vs. Post 0.33 [0.21-0.58] [Pa]; p = 0.002), aortic root (Pre 0.46 [0.31-0.58] (Pa) vs. Post 0.18 [0.12-0.25] (Pa); p = 0.001), and ventricularis of the aortic valve (Pre 1.76 [1.59-2.30] (Pa) vs. Post 0.30 [0.10-0.61] (Pa); p = 0.001) was significantly lower after LVAD implantation. No difference in WSS was observed on the fibrosa of the aortic valve (Pre 0.36 [0.22-0.53] (Pa) vs. Post 0.38 [0.38-0.52] (Pa); p = 0.850) before and after implantation. The WSS on the ascending aorta, aortic root, and ventricularis of the aortic valve leaflets was significantly altered by LVAD implantation, providing preliminary data on the potential contribution of fluid dynamics to LVAD-induced aortic insufficiency and root thrombus.

Changes in waitlist and posttransplant outcomes in patients with adult congenital heart disease after the new heart transplant allocation system.

OBJECTIVE: In 2018, the United Network for Organ Sharing (UNOS) introduced new criteria for heart allocation. This study sought to assess the impact of this change on waitlist and posttransplant outcomes in adult congenital heart disease (ACHD) recipients. METHODS: Between January 2010 and March 2020, we extracted first heart transplant ACHD patients listed from the UNOS database. We compared waitlist and post-transplant outcomes before and after the policy change. RESULTS: A total of 1206 patients were listed, 951 under the old policy and 255 under the new policy. Prior to transplant, recipients under the new policy era were more likely to be treated with extracorporeal membrane oxygenation (P = .018), and have intra-aortic balloon pumps (P < .001), and less likely to have left ventricular assist devices (P = .027).Compared to patients waitlisted in the pre-policy change era, those waitlisted in the post policy change era were more likely to receive transplants (P = .001) with no significant difference in waiting list mortality (P = .267) or delisting (P = .915). There was no difference in 1-year survival post-transplant between the groups (P = .791). CONCLUSION: The new policy altered the heart transplant cohort in the ACHD group, allowing them to receive transplants earlier with no changes in early outcomes after heart transplantation.

Difficult Airway Management in Neonates and Infants: Knowledge of Devices and a Device-Oriented Strategy.

Difficult airway management (DAM) in neonates and infants requires anesthesiologists and critical care clinicians to respond rapidly with appropriate evaluation of specific situations. Therefore, organizing information regarding DAM devices and device-oriented guidance for neonate and infant DAM treatment will help practitioners select the safest and most effective strategy. Based on DAM device information and reported literature, there are three modern options for DAM in neonates and infants that can be selected according to the anatomical difficulty and device-oriented strategy: (1) video laryngoscope (VLS), (2) supraglottic airway device (SAD), and (3) flexible fiberoptic scope (FOS). Some VLSs are equipped with small blades for infants. Advanced SADs have small sizes for infants, and some effectively function as conduits for endotracheal intubation. The smallest FOS has an outer diameter of 2.2 mm and enables intubation with endotracheal tubes with an inner diameter of 3.0 mm. DAM in neonates and infants can be improved by effectively selecting the appropriate device combination and ensuring that available providers have the necessary skills.

Poincaré Plot Area of Gamma-Band EEG as a Measure of Emergence From Inhalational General Anesthesia.

The Poincaré plot obtained from electroencephalography (EEG) has been used to evaluate the depth of anesthesia. A standalone EEG Analyzer application was developed; raw EEG signals obtained from a bispectral index (BIS) monitor were analyzed using an on-line monitoring system. Correlations between Poincaré plot parameters and other measurements associated with anesthesia depth were evaluated during emergence from inhalational general anesthesia. Of the participants, 20 were adults anesthetized with sevoflurane (adult_S E V ), 20 were adults anesthetized with desflurane (adult_D E S ), and 20 were pediatric patients anesthetized with sevoflurane (ped_S E V ). EEG signals were preprocessed through six bandpass digital filters (f0: 0.5-47 Hz, f1: 0.5-8 Hz, f2: 8-13 Hz, f3: 13-20 Hz, f4: 20-30 Hz, and f5: 30-47 Hz). The Poincaré plot-area ratio (PPAR = PP A_fx /PP A_f0 , fx = f1∼f5) was analyzed at five frequency ranges. Regardless of the inhalational anesthetic used, there were strong linear correlations between the logarithm of PP AR at f5 and BIS (R 2 = 0.67, 0.79, and 0.71, in the adult_S E V , adult_D E S , and ped_S E V groups, respectively). As an additional observation, a part of EMG activity at the gamma range of 30-47 Hz probably influenced the calculations of BIS and PP AR_f5 with a non-negligible level. The logarithm of PPAR in the gamma band was most sensitive to state changes during the emergence process and could provide a new non-proprietary parameter that correlates with changes in BIS during measurement of anesthesia depth.

Influence of aneurysmal aortic root geometry on mechanical stress to the aortic valve leaflet.

AIMS: While mechanical stress caused by blood flow, e.g. wall shear stress (WSS), and related parameters, e.g. oscillatory shear index (OSI), are increasingly being recognized as key moderators of various cardiovascular diseases, studies on valves have been limited because of a lack of appropriate imaging modalities. We investigated the influence of aortic root geometry on WSS and OSI on the aortic valve (AV) leaflet. METHODS AND RESULTS: We applied our novel approach of intraoperative epi-aortic echocardiogram to measure the haemodynamic parameters of WSS and OSI on the AV leaflet. Thirty-six patients were included, which included those who underwent valve-sparing aortic root replacement (VSARR) with no significant aortic regurgitation (n = 17) and coronary artery bypass graft (CABG) with normal AV (n = 19). At baseline, those who underwent VSARR had a higher systolic WSS (0.52 ± 0.12 vs. 0.32 ± 0.08 Pa, respectively, P < 0.001) and a higher OSI (0.37 ± 0.06 vs. 0.29 ± 0.04, respectively, P < 0.001) on the aortic side of the AV leaflet than those who underwent CABG. Multivariate regression analysis revealed that the size of the sinus of Valsalva had a significant association with WSS and OSI. Following VSARR, WSS and OSI values decreased significantly compared with the baseline values (WSS: 0.29 ± 0.12 Pa, P < 0.001; OSI: 0.26 ± 0.09, P < 0.001), and became comparable to the values in those who underwent CABG (WSS, P = 0.42; OSI, P = 0.15). CONCLUSIONS: Mechanical stress on the AV gets altered in correlation with the size of the aortic root. An aneurysmal aortic root may expose the leaflet to abnormal fluid dynamics. The VSARR procedure appeared to reduce these abnormalities.

Cardiac transplantation in adult congenital heart disease with prior sternotomy.

BACKGROUND: Adult congenital heart disease (ACHD) patients who require orthotopic heart transplantation are surgically complex due to anatomical abnormalities and multiple prior surgeries. In this study, we investigated these patients' outcomes using our institutional database. METHODS: ACHD patients who had prior intracardiac repair and subsequent heart transplant were included (2008-2018). Adult patients without ACHD were extracted as a control. A comparison of patients with functional single ventricular (SV) and biventricular (BV) hearts was performed. RESULTS: There were 9 SV and 24 BV patients. The SV group had higher central venous pressure/pulmonary capillary wedge pressure (P = .028), hemoglobin concentration (P = .010), alkaline phosphatase (P = .022), and were more likely to have liver congestion (P = .006). Major complications included infection in 16 (48.5%), temporary dialysis in 12 (36.4%), and graft dysfunction requiring perioperative mechanical support in 7 (21.2%). Overall in-hospital mortality was 15.2%. Kaplan-Meier analysis showed a higher, but not statistically significant, survival after 10 years between the ACHD and control groups (ACHD 84.9% vs. control 67.5%, P = .429). There was no significant difference in 10-year survival between SV and BV groups (78% vs. 88%, P = .467). CONCLUSIONS: Complex ACHD cardiac transplant recipients have a high incidence of early morbidities after transplantation. However, long-term outcomes were acceptable.

Outcomes of Heart Transplantation in Adult Congenital Heart Disease With Prior Intracardiac Repair.

BACKGROUND: The number of patients with adult congenital heart disease (ACHD) who require orthotopic heart transplantation has increased rapidly in the past 2 decades. This study examined heart transplant outcomes of patients with ACHD who had previous cardiac surgery by using data from the United Network for Organ Sharing database. METHODS: Between January 2008 and March 2019, patients with ACHD who underwent previous cardiac surgery and subsequent heart transplantation were identified from the United Network for Organ Sharing database. As a control group, adult patients without congenital heart disease who had previous sternotomy and subsequent heart transplantation were extracted from the database. Propensity score matching was then used to compare outcomes between the 2 groups. RESULTS: There were 793 patients in the ACHD group and 8400 patients in the control group. Among well-matched groups of 486 patients each, 30-day mortality (8.2% vs 3.9%; P = .004) and perioperative need for dialysis (22.7% vs 13.3%; P < .001) were significantly higher in the ACHD group compared with the control group. However, there was no difference in 10-year survival between the groups (ACHD 66.0% vs control 64.1%; log-rank P = .353). CONCLUSIONS: Compared with well-matched patients without ACHD but with previous sternotomy, patients with ACHD and previous intracardiac repair had a higher operative risk but similar 10-year survival.

A novel in vivo assessment of fluid dynamics on aortic valve leaflet using epi-aortic echocardiogram.

BACKGROUND: Mechanical stress caused by blood flow, such as wall shear stress (WSS) and its related parameters, is key moderator of endothelial degeneration. However, an in vivo method to measure WSS on heart valves has not been developed. METHODS: We developed a novel approach, based on vector flow mapping using intraoperative epi-aortic echocardiogram, to measure WSS and oscillatory shear index (OSI) on the aortic valve. We prospectively enrolled 15 patients with normal valves, who underwent coronary artery bypass graft. RESULTS: Systolic WSS on the ventricularis (2.40 ± 0.44 Pa [1.45-3.00 Pa]) was higher than systolic WSS on the fibrosa (0.33 ± 0.08 Pa [0.14-0.47 Pa], P < .001) and diastolic WSS on the ventricularis (0.18 ± 0.07 Pa [0.04-0.28 Pa], P < .001). Oscillatory shear index on the fibrosa was higher than on the ventricularis (0.29 ± 0.04 [0.24-0.36] vs 0.05 ± 0.03 [0.01-0.12], P < .001). A pilot study involving two patients with severe aortic regurgitation showed significantly different values in fluid dynamics. CONCLUSION: Vector flow mapping method using intraoperative epi-aortic echocardiogram is an effective way of measuring WSS and OSI on normal aortic leaflet in vivo, allowing for better understanding of the pathophysiology of aortic valve diseases.

Energetic performance index improvement after Glenn and Damus-Kaye-Stansel procedure using vector flow mapping analysis: a case report.

BACKGROUND: Echocardiography vector flow mapping can assess dynamic flow to treat congenital heart diseases. We evaluated intracardiac flow, energy loss, left ventricular output kinetic energy, and energetic performance index using vector flow mapping during Glenn and Damus-Kaye-Stansel procedures in order to assess the efficacy of the surgery. CASE PRESENTATION: A 9-month-old boy underwent Glenn and Damus-Kaye-Stansel procedures. The energy loss depends on the left ventricular preload; therefore, energy loss decreased after the Glenn procedure. After the Damus-Kaye-Stansel procedure, the kinetic energy would increase owing to the integrated systemic outflow; however, in our case, kinetic energy decreased, which was potentially explained by the fact that kinetic energy also depends on the left ventricular preload. After the Glenn and Damus-Kaye-Stansel procedures, we detected an improvement in energetic performance index, indicating that the cardiac workload improved as well. CONCLUSION: We revealed the efficiency of the Glenn and Damus-Kaye-Stansel procedures using vector flow mapping.

Molecular epidemiology of clinically high-risk Pseudomonas aeruginosa strains: Practical overview.

In recent years, numerous outbreaks of multidrug-resistant Pseudomonas aeruginosa have been reported across the world. Once an outbreak occurs, besides routinely testing isolates for susceptibility to antimicrobials, it is required to check their virulence genotypes and clonality profiles. Replacing pulsed-field gel electrophoresis DNA fingerprinting are faster, easier-to-use, and less expensive polymerase chain reaction (PCR)-based methods for characterizing hospital isolates. P. aeruginosa possesses a mosaic genome structure and a highly conserved core genome displaying low sequence diversity and a highly variable accessory genome that communicates with other Pseudomonas species via horizontal gene transfer. Multiple-locus variable-number tandem-repeat analysis and multilocus sequence typing methods allow for phylogenetic analysis of isolates by PCR amplification of target genes with the support of Internet-based services. The target genes located in the core genome regions usually contain low-frequency mutations, allowing the resulting phylogenetic trees to infer evolutionary processes. The multiplex PCR-based open reading frame typing (POT) method, integron PCR, and exoenzyme genotyping can determine a genotype by PCR amplifying a specific insertion gene in the accessory genome region using a single or a multiple primer set. Thus, analyzing P. aeruginosa isolates for their clonality, virulence factors, and resistance characteristics is achievable by combining the clonality evaluation of the core genome based on multiple-locus targeting methods with other methods that can identify specific virulence and antimicrobial genes. Software packages such as eBURST, R, and Dendroscope, which are powerful tools for phylogenetic analyses, enable researchers and clinicians to visualize clonality associations in clinical isolates.

Secondary in-hospital epidemiological investigation after an outbreak of Pseudomonas aeruginosa ST357.

The secondary in-hospital epidemiological investigation for drug-resistant Pseudomonas aeruginosa infections was conducted to evaluate the in-hospital situation and identify any associations between exoenzyme genotypes and other genotypes and antimicrobial resistance characteristics, at the University Hospital in Kyoto, Japan, following a reported outbreak of antimicrobial-resistant P. aeruginosa ST357 between 2005 and 2014. Twelve of the 546 P. aeruginosa isolates collected during the follow-up period were resistant to more than two classes of antimicrobials. All isolates were resistant to fluoroquinolones and 8 (66.7%) showed carbapenem resistance. None of the isolates fulfilled the clinical criteria for multidrug-resistant P. aeruginosa. All isolates were metallo-ß-lactamase test-negative. Among five exoS (-)exoU (+) isolates, three possessing a class 1 integron with gene cassette aadB + cmlA6 were classified as ST357, and one isolate containing a class 1 integron with aacA31 was ST235. Collectively, the second survey results confirm that the initial outbreak is currently undergoing convergence. By combining data from the first and second surveys, we showed that prevalent STs such as ST357 and ST235 are associated with fluoroquinolone resistance, class 1 integron-associated resistance to ß-lactams and aminoglycosides, and cytotoxic exoU (+) genotypes. With the current worldwide spread of ST357 and ST235 isolates, it is important to evaluate epidemiological trends for high-risk P. aeruginosa isolates by continuous hospital monitoring.

The protective effects of nasal PcrV-CpG oligonucleotide vaccination against Pseudomonas aeruginosa pneumonia.

An effective vaccine against Pseudomonas aeruginosa would be hugely beneficial to people who are susceptible to the serious infections it can cause. Vaccination against PcrV of the P. aeruginosa type III secretion system is a potential prophylactic strategy for improving the incidence and prognosis of P. aeruginosa pneumonia. Here, the effect of nasal PcrV adjuvanted with CpG oligodeoxynucleotide (CpG) was compared with a nasal PcrV/aluminum hydroxide gel (alum) vaccine. Seven groups of mice were vaccinated intranasally with one of the following: 1, PcrV-CpG; 2, PcrV-alum; 3, PcrV alone; 4, CpG alone; 5, alum alone; 6 and 7, saline control. Fifty days after the first immunization, anti-PcrV IgG, IgA and IgG isotype titers were measured; significant increases in these titers were detected only in the PcrV-CpG vaccinated mice. The vaccinated mice were then intratracheally infected with a lethal dose of P. aeruginosa and their body temperatures and survival monitored for 24 hr, edema, bacteria, myeloperoxidase activity and lung histology also being evaluated at 24 hr post-infection. It was found that 73% of the PcrV-CpG-vaccinated mice survived, whereas fewer than 30% of the mice vaccinated with PcrV-alum or adjuvant alone survived. Lung edema and other inflammation-related variables were less severe in the PcrV-CpG group. The significant increase in PcrV-specific IgA titers detected following PcrV-CpG vaccination is probably a component of the disease protection mechanism. Overall, our data show that intranasal PcrV-CpG vaccination has potential efficacy for clinical application against P. aeruginosa pneumonia.

An outbreak of fluoroquinolone-resistant Pseudomonas aeruginosa ST357 harboring the exoU gene.

Antimicrobial-resistant isolates of Pseudomonas aeruginosa collected from 2005 to 2014 in a university hospital in Kyoto, Japan, were retrospectively analyzed by multilocus sequence typing (MLST), exoenzyme genotype determination, integron characterization, and clinical associations. During the study, 1573 P. aeruginosa isolates were detected, and 41 of these were resistant to more than two classes of antimicrobial agents. Twenty-five (61.0%) isolates were collected from urine. All isolates were resistant to ciprofloxacin, 8 (19.5%) isolates showed resistance to imipenem/cilastatin, and 8 (19.5%) isolates showed resistance to meropenem. None of the isolates fulfilled the clinical criteria for multidrug-resistant P. aeruginosa. All isolates were negative in the metallo-ß lactamase test. Thirty-six (87.8%) isolates were of the exoS-exoU+ genotype and 5 (12.2%) isolates were of the exoS+exoU- genotype. Among 36 exoS-exoU+ isolates, 33 (80.5%) were ST357, and 3 (7.3%) were ST235. Five isolates of exoS+exoU- were ST186, ST244, ST314, ST508, and ST512. Thirty-three isolates were positive for class 1 integrons and four different class 1 integrons were detected: aminoglycoside (2') adenyltransferase and chloramphenicol transporter (AadB+CmlA6), OXA-4 ß-lactamase and aminoglycoside 3'-adenyltransferase (OXA4+AadA2), AadB alone, and aminoglycoside acetyltransferase alone (AacA31). Among the 41 patients from which the isolates originated, the most common underlying disease was cancer in 16 patients (39%), and 9 patients (22.0%) died during the hospitalization period. There was no statistical correlation between MLST, exoenzyme genotype, and patient mortality. The results indicated outbreaks of fluoroquinolone-resistant P. aeruginosa in immunocompromised patients mainly due to the propagation of potentially virulent ST357 isolates possessing the exoU+ genotype.

Energetic performance analysis of staged palliative surgery in tricuspid atresia using vector flow mapping.

BACKGROUND: Staged palliative surgery markedly shifts the balance of volume load on a single ventricle and pulmonary vascular bed. Blalock-Taussig shunt necessitates a single ventricle eject blood to both the systemic and pulmonary circulation. On the contrary, bidirectional cavopulmonary shunt release the single ventricle from pulmonary circulation. CASE PRESENTATION: We report a case of tricuspid atresia patient who underwent first palliative surgery and second palliative surgery. Volume loading condition was assessed by energetic parameters (energy loss, kinetic energy) intraoperatively using vector flow mapping. These energetic parameters can simply indicate the volume loading condition. CONCLUSION: Vector flow mapping was useful tool for monitoring volume loading condition in congenital heart disease surgery.

Brachiocephalic Vein Perforation During Cannulation of Internal Jugular Vein: A Case Report.

We report a rare complication of right brachiocephalic vein perforation during ultrasound-guided cannulation of the right internal jugular vein (IJV) in a patient with a tortuous common carotid artery (CCA). We suspect that the tortuous CCA displaced the IJV, which caused misplacement of the J-tip guidewire into the subclavian vein. The stiff dilator sheath introduced over the guidewire then perforated the wall of the brachiocephalic vein, causing massive hemothorax. This was diagnosed by videothoracoscopy. Anesthesiologists should be aware of the possibility of guidewire malposition during IJV catheterization in patients with a tortuous CCA.