Continuous Myocardial Perfusion during Distal Anastomosis of Acute Type A Aortic Dissection.

BACKGROUND: The effect of continuous myocardial perfusion (CMP) on the surgical results of acute type A aortic dissection (ATAAD) remains unclear. METHODS: From January 2017 to March 2022, 141 patients who underwent ATAAD (90.8%) or intramural hematoma (9.2%) surgery were reviewed. Fifty-one patients (36.2%) received proximal-first aortic reconstruction and CMP during distal anastomosis. Ninety patients (63.8%) underwent distal-first aortic reconstruction and were placed in traditional cold blood cardioplegic arrest (CA; 4°C, 4:1 blood-to-Plegisol) throughout the procedure. The preoperative presentations and intraoperative details were balanced using inverse probability of treatment weighting (IPTW). Their postoperative morbidity and mortality were analyzed. RESULTS: The median age was 60 years. The incidence of arch reconstruction in the unweighted data was higher in the CMP compared with the CA group (74.5 vs 52.2%, p = 0.017) but was balanced after IPTW (62.4 vs 58.9%, p = 0.932, standardized mean difference = 0.073). The median cardiac ischemic time was lower in the CMP group (60.0 vs 130.9 minutes, p < 0.001), but cerebral perfusion time and cardiopulmonary bypass time were similar. The CMP group did not demonstrate any benefit in the reduction of the postoperative maximum creatine kinase-MB ratio (4.4 vs 5.1% in CA, p = 0.437) or postoperative low cardiac output (36.6 vs 24.8%, p = 0.237). Surgical mortality was comparable between groups (15.5% in CMP vs 7.5% in the CA group, p = 0.265). CONCLUSION: Application of CMP during distal anastomosis in ATAAD surgery, irrespective of the extent of aortic reconstruction, reduced myocardial ischemic time but did not improve cardiac outcome or mortality.

The Potential Neurological Impact of Intraoperative Hyponatremia Using Histidine-Tryptophan-Ketoglutarate Cardioplegia Infusion in Adult Cardiac Surgery.

Background and Objectives: The relationship between histidine-tryptophan-ketoglutarate (HTK)-induced hyponatremia and brain injury in adult cardiac surgery patients is unclear. This study analyzed postoperative neurological outcomes after intraoperative HTK cardioplegia infusion. Materials and Methods: A prospective cohort study was conducted on 60 adult patients who underwent cardiac surgery with cardiopulmonary bypass. Of these patients, 13 and 47 received HTK infusion and conventional hyperkalemic cardioplegia, respectively. The patients' baseline characteristics, intraoperative data, brain injury markers, Mini-Mental State Examination (MMSE) scores, and quantitative electroencephalography (qEEG) data were collected. Electrolyte changes during cardiopulmonary bypass, the degree of hyponatremia, and any associated brain insults were evaluated. Results: The HTK group presented with acute hyponatremia during cardiopulmonary bypass, which was intraoperatively corrected through ultrafiltration and normal saline administration. Postoperative sodium levels were higher in the HTK group than in the conventional cardioplegia group. The change in neuron-specific enolase levels after cardiopulmonary bypass was significantly higher in the HTK group (p = 0.043). The changes showed no significant differences using case-control matching. qEEG analysis revealed a significant increase in relative delta power in the HTK group on postoperative day (POD) 7 (p = 0.018); however, no significant changes were noted on POD 60. The MMSE scores were not significantly different between the two groups on POD 7 and POD 60. Conclusions: HTK-induced acute hyponatremia and rapid correction with normal saline during adult cardiac surgeries were associated with a potential short-term but not long-term neurological impact. Further studies are required to determine the necessity of correction for HTK-induced hyponatremia.

Predictors and Outcomes of Acute Brain Injury in Patients on Venoarterial Extracorporeal Membrane Oxygenation after Cardiopulmonary Resuscitation.

Background: Venoarterial (V-A) extracorporeal membrane oxygenation (ECMO) after cardiac arrest often predisposes patients to acute brain injury (ABI), which affects survival and neurological performance. The investigation of the predictors of ABI will be beneficial for further management. Objectives: To explore the predictors and outcomes of ABI and intracerebral hemorrhage (ICH) in patients experiencing cardiac arrest and cardiopulmonary resuscitation (CPR) with V-A ECMO support. Methods: We retrospectively analyzed 150 patients who successfully weaned from V-A ECMO support after pre-ECMO CPR at our institution from January 2009 to December 2021. Short-term and long-term outcomes were evaluated. Characteristics before and during ECMO were analyzed for determining the predictors of ABI and ICH. Results: Of the 150 patients, 66 (44.0%) had ABI. ABI was associated with higher in-hospital mortality (62.1% vs. 21.4%, p < 0.0001) and poorer long-term survival after discharge (p = 0.002). Patients who survived to discharge with ABI had significantly more severe neurological deficits at discharge (84.0% vs. 42.4%, p < 0.0001) and improved little at one year after discharge (33.3% vs. 11.4%, p = 0.027). We found that CPR duration [odds ratio (OR) = 1.04, p = 0.003] was the independent risk factor for ABI, whereas lower platelet counts was the independent risk factor for ICH (OR = 0.96, p = 0.019). Conclusions: After CPR, development of ABI during V-A ECMO support impacted survival and further neurological outcome. Longer CPR duration before ECMO set up significantly increases the occurrence of ABI. Besides, severe thrombocytopenia during ECMO support increases the possibility of ICH.

Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitor Improves the Vascular Function of Arteriovenous Fistula in Rats with Hyperglycemia.

Objectives: Few evidence-based medications to improve the primary patency of arteriovenous fistulas in patients with diabetes who require hemodialysis are available. We investigated whether proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) could improve arteriovenous fistula function through pleiotropic effects in a rat model of hyperglycemia. Methods: Ex vivo effects of PCSK9i on the aorta of Sprague-Dawley (SD) rats were investigated using an organ bath system. For in vivo experiments, an abdominal aortocaval (AC) fistula was generated in SD rats (200-250 g) after inducing hyperglycemia through streptozotocin administration (80 mg/kg, intraperitoneal). Alirocumab (50 mg/kg/week, subcutaneous) was administered on the day of fistula surgery and day 7. Echocardiography, blood flow through the aorta-limb, vasomotor reactivity, and serum biochemistry were examined on D14. Furthermore, enzyme-linked immunosorbent assay and immunoblotting were performed. Results: PCSK9i induced aorta relaxation ex vivo through a potassium channel-associated mechanism. PCSK9i significantly improved blood flow and preserved endothelial function without changes in cardiac function and serum lipid levels in rats with hyperglycemia. The levels of lectin-like oxidized low-density lipoprotein receptor-1, superoxide dismutase, cyclooxygenase-2, caspase-1, and interleukin-1ß were significantly reduced in the treatment group. PCSK9i decreased the ratio of phosphorylated to total p38 mitogen-activated protein kinase and extracellular signal-regulated kinase in the aorta of rats with hyperglycemia. Conclusions: Short-term treatment with PCSK9i preserved endothelial function, induced vascular dilatation, and increased blood flow in the AC fistula of rats with hyperglycemia. The pleiotropic mechanisms were associated with the suppression of oxidative stress and tissue inflammation during hyperglycemia.

Influence of confirmed viral infection on adult acute fulminant myocarditis supported with extracorporeal membrane oxygenation.

BACKGROUND: The impact of etiologies of acute fulminant myocarditis (AFM), which requires extracorporeal membrane oxygenation (ECMO), on clinical outcomes remains unknown. This study aimed to investigate the risk factors for ECMO weaning and mortality among patients with AFM due to viral etiologies in a tertiary referral medical center. METHODS: We included 33 adults with AFM who received ECMO and were admitted between January 2002 and January 2021. General demographics, laboratory data, echocardiography findings, and long-term outcomes were analyzed for confirmed viral etiology and unconfirmed etiology groups. RESULTS: The overall hospital survival rate was 54.5%. The age, sex, severity of the hemodynamic condition, and cardiac rhythm were similar between the two groups. Multivariate Cox regression analysis revealed that a confirmed viral etiology (HR 4.201, 95% CI 1.061-16.666), peri-ECMO renal replacement therapy (RRT) (HR 9.804, 1.140-83.333) and a high positive end-expiratory pressure (PEEP) in the ventilator settings at 24 h after ECMO (HR 1.479, 1.020-2.143) were significant prognostic factors for in-hospital mortality. Peri-ECMO RRT was also a significant negative prognostic factor for successful ECMO weaning (OR 0.061, 0.006-0.600) in the multivariate logistic model. CONCLUSIONS: Among AFM patients receiving ECMO support, RRT use was associated with a decreased chance of survival to ECMO weaning. Multiple organ dysfunction and a high PEEP were also predictive of a lower chance of hospital survival. Those with a confirmed diagnosis of viral myocarditis may require more medical attention due to the higher risk of hospital mortality than those without a definite diagnosis.

Cognitive Function Deterioration After Cardiopulmonary Bypass: Can Intraoperative Optimal Cerebral Regional Tissue Oxygen Saturation Predict Postoperative Cognitive Function?

OBJECTIVE: Cognitive impairment is a common neurologic complication after cardiac surgery with cardiopulmonary bypass (CPB). This study evaluated postoperative cognitive function to determine predictors of cognitive dysfunction, including intraoperative cerebral regional tissue oxygen saturation (rSO2). DESIGN: A prospective observational cohort study. SETTING: At a single academic tertiary-care center. PARTICIPANTS: A total of 60 adults undergoing cardiac surgery with CPB from January to August 2021. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients underwent Mini-Mental State Examination (MMSE) and quantified electroencephalography (qEEG) 1 day before cardiac surgery, 7 days postoperatively (POD7), and POD60. Intraoperative cerebral rSO2 was monitored continuously. For MMSE, no significant decrease in MMSE score was found on POD7 versus preoperatively (p = 0.09), but POD60 scores showed significant improvement compared with both preoperative (p = 0.02) and POD7 scores (p < 0.001). On qEEG, relative theta power on POD7 was increased versus preoperatively (p < 0.001), but it was decreased on POD60 (POD7 versus POD60, p < 0.001), and was close to preoperative data (p > 0.99). Baseline rSO2 was an independent factor for postoperative MMSE. Both baseline and mean rSO2 showed a significant influence in postoperative relative theta activity, whereas mean rSO2 was the only predictor for the theta-gamma ratio (p = 0.04). CONCLUSIONS: The MMSE in patients undergoing CPB declined at POD7 and recovered by POD60. Lower baseline rSO2 indicated a higher potential for MMSE decline at POD60. Inferior intraoperative mean rSO2 was related to higher postoperative relative theta activity and theta-gamma ratio, implying subclinical or further cognitive impairment.

Safety Time and Optimal Temperature of Unilateral Antegrade Cerebral Perfusion in Acute Type A Aortic Dissection: A Single-Center 15-Year Experience.

Background: The optimal level of hypothermia and safe time of unilateral antegrade cerebral perfusion (uACP) in acute type A aortic dissection (ATAAD) repair remain controversial. Objectives: To analyze the association of uACP time and circulatory arrest temperature with surgical outcomes of ATAAD. Methods: We retrospectively analyzed 263 patients who had undergone ATAAD repair between 2006 and 2020 using uACP. The patients were stratified by three chronologically equivalent periods (period 1, 2006 to 2010; period 2, 2011 to 2015; period 3, 2016 to 2020) to demonstrate the decade-long evolution of surgical strategy and outcomes. Results: The mean age of the patients was 59.4 ± 12.5 years, and 68.8% were male. The hospital mortality rates were 15.1%, 12.9%, and 11.0% from period 1 to 3 (p = 0.740). The median circulatory arrest temperatures were 20, 23, and 25 °C (p < 0.001), respectively, and the median uACP times were 72, 59, and 41 minutes (p < 0.001). The incidence rates of postoperative permanent neurologic deficits were 13.2%, 10.9%, and 18.3% (p = 0.312), and those of transient neurologic deficits were 9.4%, 10.9%, and 11.9% (p = 0.936), respectively. Multivariate logistic regression analysis showed that uACP time ≥ 60 minutes was an independent predictor of hospital mortality rather than postoperative stroke. ROC curve analysis estimated an optimal cutoff value of 52 minutes of uACP time when the circulatory arrest temperature was ≥ 25 °C to predict hospital mortality (area under the curve: 0.72). Conclusions: Unilateral antegrade cerebral perfusion time was associated with hospital mortality after ATAAD surgery. A safe threshold of 50 to 60 minutes of uACP should be considered.

Prothymosin α Gene Transfer Modulates Myocardial Remodeling after Ischemia-Reperfusion Injury.

Background: Prothymosin α (ProT), a polypeptide, attenuates inflammation and inhibits transforming growth factor (TGF)-ß signaling in pulmonary tissues. We investigated the potential role of ProT in myocardial ischemia-reperfusion (MyoIR) injury using ProT cDNA transfer. Methods: Serum ProT levels were investigated in cardiogenic shock patients with MyoIR (n = 9). In addition, the myocardium of Sprague-Dawley rats (n = 52) was subjected to 25 min of ischemia followed by an injection of adenoviral vectors (2 × 109 plaque-forming units) carrying ProT or the luciferase gene, 10 min before reperfusion. Echocardiography, serum ProT, and biochemical analyses of organ functions were performed before euthanasia, 14 days after treatment. Immunohistochemistry and immunoblotting of the myocardial tissue were also performed. Results: Serum ProT levels were transiently elevated in the rats and patients early after MyoIR, which was reduced to baseline levels in control rats and patients. ProT gene transfer persistently mobilized ProT serum levels, reduced dilatation, attenuated fibrotic changes, and preserved the left ventricular ejection fraction after MyoIR. Tissue thrombospondin-1 level was abundant, and matrix metalloproteinase-2, collagen I, and collagen IV levels were decreased in the treatment group. While TGF-ß protein level remained stable, ProT transduction mobilized Smad7, which counteracted TGF-ß. ProT reduced tissue microRNA-223 expression, inhibited the associated interleukin-1ß, and preserved RAS p21 protein activator 1 protein abundance. Conclusions: An increase in transient serum ProT levels could be a protective response in the acute stage of MyoIR. ProT gene transfer further preserved ventricular morphology and function through anti-inflammatory and anti-fibrotic effects in the subacute stage after injury.

Early bioprosthesis failure in mitral valve replacement.

The causes of early bioprosthesis failure include infective endocarditis, pannus formation, and structural valve deterioration. We reported a patient who suffered from early mitral bioprosthesis failure due to leaflets restricted by the subvalvular apparatus and early pannus formation. In patients with symptoms relapse and mitral regurgitation recurrence early after mitral valve replacement, early pannus formation needs to be anticipated, and surgical intervention should be performed if symptoms persist after medical treatment.

Assessing the quality of electronic medical records as a platform for resident education.

BACKGROUND: Previous studies have assessed note quality and the use of electronic medical record (EMR) as a part of medical training. However, a generalized and user-friendly note quality assessment tool is required for quick clinical assessment. We held a medical record writing competition and developed a checklist for assessing the note quality of participants' medical records. Using the checklist, this study aims to explore note quality between residents of different specialties and offer pedagogical implications. METHODS: The authors created an inpatient checklist that examined fundamental EMR requirements through six note types and twenty items. A total of 149 records created by residents from 32 departments/stations were randomly selected. Seven senior physicians rated the EMRs using a checklist. Medical records were grouped as general medicine, surgery, paediatric, obstetrics and gynaecology, and other departments. The overall and group performances were analysed using analysis of variance (ANOVA). RESULTS: Overall performance was rated as fair to good. Regarding the six note types, discharge notes (0.81) gained the highest scores, followed by admission notes (0.79), problem list (0.73), overall performance (0.73), progress notes (0.71), and weekly summaries (0.66). Among the five groups, other departments (80.20) had the highest total score, followed by obstetrics and gynaecology (78.02), paediatrics (77.47), general medicine (75.58), and surgery (73.92). CONCLUSIONS: This study suggested that duplication in medical notes and the documentation abilities of residents affect the quality of medical records in different departments. Further research is required to apply the insights obtained in this study to improve the quality of notes and, thereby, the effectiveness of resident training.

Rosuvastatin Failed to Improve Arteriovenous Fistula Patency for Hemodialysis in Diabetic Patients - A Randomized Clinical Trial.

BACKGROUND: Very limited therapeutic strategies exist to prevent the primary failure of arteriovenous (AV) fistulas in patients with diabetes. OBJECTIVES: To investigate whether rosuvastatin could improve the primary patency of AV fistulas in diabetic patients with stage 5 chronic kidney disease (CKD). METHODS: This was a double-blind randomized clinical trial. From July 2012 to September 2018, patients aged between 18 and 65 years with type 2 diabetes and stage 5 CKD were randomized to receive placebo or rosuvastatin (5 mg/day) for 7 days prior to the creation of an AV fistula on the forearm until the 21st day after surgery. Patients were followed up for 180 days after the operation. The primary composite endpoint was the development of fistula immaturity or stenosis. The secondary endpoints were changes in inflammatory markers, oxidative stress, and occurrence of postoperative complications. RESULTS: A total of 60 patients were enrolled in the study. Rosuvastatin resulted in a 20% reduction in total cholesterol from postoperative day 0 to 28 (p = .0006). The overall rate of AV fistula failure (immaturity or stenosis) was 30%, with no significant difference between patients receiving rosuvastatin and those receiving the placebo (33.3% vs. 26.7%, p = .5731). Although not statistically significant, the administration of rosuvastatin might have increased the incidence of postoperative complications (2.99 vs. 2.39 event rate per 1000 patient-days; odds ratio, 1.33; p = .5986). CONCLUSIONS: Rosuvastatin showed no significant beneficial effects on the primary patency of AV fistulas in diabetic patients with stage 5 CKD, but might have been associated with the risk of drug-related complications.

Post-Coronary Artery Bypass Medications in Dialysis Patients: Do We Need to Change Strategies?

BACKGROUND: Coronary artery bypass grafting (CABG) is frequently performed in patients with end-stage renal disease (ESRD) together with severe coronary artery disease, after which, patients with ESRD have higher surgical risk and poorer long-term outcomes. We report our experience in patients with ESRD who survived in CABG and identify predictors of long-term outcomes. METHODS: We retrospectively investigated 93 consecutive patients with ESRD who survived to discharge after isolated CABG between January 2005 and December 2016 at our institution. Long-term outcomes, including all-cause mortality after discharge, readmission due to major adverse cardiac events, and reintervention, were evaluated. Predictors affecting long-term outcomes were also analyzed. RESULTS: The rates of freedom from all-cause mortality after discharge in 1, 3, 5, and 10 years were 92.1, 81.3, 71.9, and 34.9%, respectively. The rates of freedom from readmission due to major adverse cardiac events in 1, 3, 5, and 10 years were 90.7, 79.1, 69.9, and 55.6%, respectively. The rates of freedom from reintervention in 1, 3, 5, and 10 years were 95.3, 86.5, 79.0, and 66.6%, respectively. Postoperative ß-blocker and statin use significantly improved overall long-term survival (ß-blocker, p = 0.013; statin, p = 0.009). After case-control matching, patients who received statins showed better long-term survival than those without statins. The comparison of long-term survival between patients with and without ß-blockers showed no significant difference after matching. CONCLUSIONS: After CABG, dialysis patients who survived to discharge had acceptable long-term overall survival. Post-CABG statin use in dialysis patients is a predictor of better long-term survival.

Exendin-4, a glucagon-like peptide-1 analogue, accelerates diabetic wound healing.

BACKGROUND: Diabetes disregulates inflammatory responses and impairs vascular function in wounds. Glucagon-like peptide-1 receptor (Glp-1R) agonists are hypoglycemic agents with pleiotropic vascular protective and anti-inflammatory effects. The therapeutic potential of a Glp-1 analogue in a diabetic rat model of excisional wound injury was investigated. MATERIALS AND METHODS: Excisional wounds were created on the dorsum of streptozotocin-induced diabetic rats, which received placebo or Glp-1 analogue exendin-4 (Ex4; 0.5 µg/kg/d, i.p.) for 2 wk. The final-to-initial wound area ratio was measured for 14 d. Levels of superoxide anions and proinflammatory cytokines in the wound were determined. Angiogenesis was assessed using the Matrigel assay. Expression levels of proangiogenic factors and extracellular matrix proteins were measured. RESULTS: Ex4 restored wound closure in diabetic rats and significantly suppressed the generation of superoxide anions and interleukin-6 in wounds. The number of circulating endothelial progenitor (CD34+/KDR+) cells increased significantly in Ex4-treated diabetic rats, which also showed increased capillary tube formation. Protein levels of vascular endothelial growth factor receptor-2, phosphorylated endothelial nitric oxide synthase, matrix metalloproteinase-2, and transforming growth factor-ß were increased in diabetic rats receiving Ex4 therapy. Ex4-enhanced vascularity, dermal regeneration, and epidermal regeneration, while it decreased hemorrhaging and increased the number of proliferative cells in the dermis. CONCLUSIONS: Ex4 accelerated excisional wound healing in subjects with diabetes. Glp-1R activation attenuates inflammatory response and enhances angiogenesis during the early proliferation phase of wound healing in diabetic subjects, while it enhances transforming growth factor-ß/matrix metalloproteinase-mediated regeneration during the maturation phase. These results suggest that Ex4 could be used as a standard hypoglycemic agent in diabetic patients with wound injury.

High-dose calcineurin inhibitor-free everolimus as a maintenance regimen for heart transplantation may be a risk factor for Pneumocystis pneumonia.

BACKGROUND: Everolimus reduces the incidence of cardiac-allograft vasculopathy (CAV) and is less renally toxic than are calcineurin inhibitors (CNIs). We evaluated the safety of CNI-free everolimus for post-heart transplant (HTx) patients. METHODS: We retrospectively reviewed the records of 36 consecutive patients who had undergone an HTx between January 2006 and December 2013 in National Cheng Kung University Hospital. All patients initially had been treated with the standard tacrolimus regimen. The Study group-12 patients with CAV, renal impairment, or a history of malignancy-were switched from tacrolimus to everolimus. The Control group consisted of 19 patients who remained on the standard regimen. The target everolimus trough concentration was 8-14 ng/mL. The primary outcome was survival, and the secondary outcomes were bacterial, viral, fungal, and other infections; Pneumocystis jirovecii pneumonia (PJP); and rejection (≥2R). RESULTS: During a 53.3±25.6-month follow-up, the survival rate, rejection rate, and number of infections, except for PJP, were not significantly different between the two groups. In the Study group, 6 patients were diagnosed with PJP 33±18.2 months after switching. None of the Control group patients were diagnosed with PJP during follow-up. CONCLUSIONS: A high-dose CNI-free everolimus maintenance regimen might yield a higher incidence of post-transplantation PJP.

Isoflurane Impairs Motor Function Recovery by Increasing Neuroapoptosis and Degeneration During Spinal Ischemia-Reperfusion Injury in Rats.

BACKGROUND: Spinal cord ischemia (SCI) leads to variable degrees of neurologic deficit in patients undergoing major cardiovascular surgery. The effect of intraoperative neuroprotection against SCI and the subsequent ischemia-reperfusion injury is still limited. Because isoflurane is a commonly used anesthetic agent during major operation, and its neuroprotective and neurotoxicity effects have both been discussed, this study aimed to investigate the effect of isoflurane on the spinal cord's functional recovery in a rat model of cord ischemia. METHODS: Rats were randomly anesthetized by parenteral anesthetic (Zoletil) and isoflurane (0% and 1.5% v/v in oxygen). Cord ischemia was induced by cross-clamping of thoracic aorta at the level of T5, and cord perfusion was resumed after 25 minutes. The motor function was assessed independently up to 48 hours after reperfusion. Spinal cords were harvested and analyzed for molecular and histologic changes. RESULTS: The locomotor rating scale was significantly reduced in rats that received isoflurane treatment during SCI at 12 to 48 hours after reperfusion. Isoflurane enhanced the expression of heme oxygenase-1, glial fibrillary acidic protein, cleaved caspase-3, and Iba-1 in the spinal cord. Increased apoptotic cells and the presence of axonal damage were also observed in the histologic sections. CONCLUSION: Our results demonstrate that the administration of inhaled isoflurane in spinal cord ischemia-reperfusion injury impairs the recovery of motor function. This response is associated with the neuronal apoptosis and degeneration. This study highlights the potential adverse effect of isoflurane on the functional recovery of ischemic spinal cord during major aortic surgery.

An in vivo study on endothelialized vascular grafts produced by autologous biotubes and adipose stem cells (ADSCs).

Currently, commercial synthetic vascular grafts made from Dacron and ePTFE for small-diameter, vascular applications (<6 mm) show limited reendothelization and are less compliant, often resulting in thrombosis and intimal hyperplasia. Although good blood compatibility can be achieved in autologous arteries and veins, the number of high quality harvest sites is limited, and the grafts are size-mismatched for use in the fistula or cardiovascular bypass surgery; thus, alternative small graft substitutes must be developed. A biotube is an in vivo, tissue-engineered approach for the growth of autologous grafts through the subcutaneous implantation of an inert rod through the inflammation process. In the present study, we embedded silicone rods with a diameter of 2 mm into the dorsal subcutaneous tissue of rabbits for 4 weeks to grow biotubes. The formation of functional endothelium cells aligned on the inner wall surface was achieved by seeding with adipose stem cells (ADSCs). The ADSCs-seeded biotubes were implanted into the carotid artery of rabbits for more than 1 month, and the patency rates and remodeling of endothelial cells were observed by angiography and fluorescence staining, respectively. Finally, the mechanical properties of the biotube were also evaluated. The fluorescence staining results showed that the ADSCs differentiated not only into endothelia cells but also into smooth muscle cells. Moreover, the patency of the ADSCs-seeded biotube remained high for at least 5 months. These small-sized ADSCs-seeded vascular biotubes may decrease the rate of intimal hyperplasia during longer implantation times and have potential clinical applications in the future.

Right Ventricular Pacing-Induced Heart Failure after Mitral Valve Replacement.

UNLABELLED: It is an unfortunate fact that pacing-induced heart failure after cardiac surgery is frequently ignored by medical professionals. A 60-year-old woman with chronic atrial fibrillation with a single-lead right ventricular permanent pacemaker for a prolonged ventricular pause underwent mitral valve replacement 6 months later for severe stenosis (NYHA functional class III). The patient's pacing rate was increased from the preoperative level of 60 beats per minute (bpm) to 70 bpm in order to facilitate weaning from the cardiopulmonary bypass. However, her postoperative low cardiac output continued to progress, despite the presence of inotropes. The patient's cold limbs and oliguria persisted until she underwent echocardiographic imaging, which showed dyssynchronous ventricular contraction 29 days post-surgery but which improved after the pacing rate was reduced below her spontaneous rate. Ultimately, clinicians should exercise caution when increasing right ventricular pacing for postoperative stunned myocardium. Due to the problems that can arise from an increased pacing rate, postoperative pacing strategy in patients complicated with low cardiac output after mitral valve replacement merits further discussion. KEY WORDS: Dyssynchrony; Mitral valve replacement; Right ventricular pacing; Stunned myocardium.

Mobilization of Endothelial Progenitor Cells Following Creation of Arteriovenous Access in Patients with End-Stage Renal Disease.

BACKGROUND: A patent arteriovenous (AV) fistula induces activation of regional vascular endothelium and vascular shear force. Shear stress is an important physiological force in mobilizing endothelial progenitor cells (EPCs). This study aimed to explore the perioperative changes of circulating EPC levels for patients who require hemodialysis and underwent radiocephalic fistula operation. METHODS: This prospective cohort study included patients who received a radiocephalic fistula surgery when they were between 25 and 65 years of age. The subjects were followed for 90 days postoperatively for any stenotic events or immaturity of the fistula. Blood samples were obtained on the day before surgery and at postoperation day (POD) 3 and 30. CD133+/KDR+ cells, defined as EPCs, were analyzed using flow cytometry. Blood flow of the fistula was followed on POD 3 and 30. RESULTS: A total of 30 patients were enrolled in the study from July 2009 to December 2011. One patient dropped out of the study and seven patients developed a stenotic (or immature) AV fistula (7/29, 24.1%). There were positive linear relationships between EPC numbers and shear rate postoperatively, which were more significant on POD 30. In addition, postoperative mobilization of EPCs was significantly higher in patients who developed a stenotic fistula than those without. CONCLUSIONS: The mobilization of circulating EPCs correlated with a compromised arteriovenous fistula. The biological significance of increased EPC numbers need to be determined in future studies. KEY WORDS: Arteriovenous fistula; Endothelial progenitor cells.