Bacterial cellulose as a promising material for pulmonary valve prostheses: In vivo study in a sheep model.

OBJECTIVES: Currently, no consensus exists regarding the most durable prosthesis for pulmonary valve replacement. Bacterial cellulose is a resistant, nonbiodegradable, nonpyrogenic bioimplant with low hemolysis and clotting properties. We hypothesized that bacterial cellulose heart valve prostheses could be an attractive alternative for pulmonary valve replacement. METHODS: We conducted a large animal model experiment in three adult sheep. The animals underwent open-heart surgery and cardiopulmonary bypass for bacterial cellulose conduit implantation in the pulmonary position. The sheep were followed for seven months, and clinical and laboratory parameters were analyzed. Echocardiographic evaluations were performed at 3 and 7 months. After seven months, the sheep were sacrificed and an autopsy was performed. The explanted conduits were radiologically and histopathologically analyzed. RESULTS: All sheep survived the operation, showing good recovery and normal health status; no adverse events were noted during the 7-month postoperative follow-up. Interval laboratory findings were normal with no signs of hemolysis or infection. Echocardiographic analysis after 7 months revealed a normal mean pressure gradient with excellent cusp motion and coaptation; a trace of regurgitation was found in two sheep. X-ray analysis of the explanted conduits revealed no structural defects in the leaflets with minimal calcification. Histological examination showed slight thickening of the conduit by pannus formation. No material failure, no calcification inside the material, and only minor calcification extrinsic to the matrix were observed. CONCLUSIONS: This pilot study provides evidence that bacterial cellulose may be suitable for pulmonary valve prostheses and surgical pulmonary artery plasty. Further studies on the high pressure side of the left heart are needed.

Filter life span in postoperative cardiovascular surgery patients requiring continuous renal replacement therapy, using a postdilution regional citrate anticoagulation continuous hemofiltration circuit.

BACKGROUND: Regional citrate anticoagulation (RCA) is the recommended standard for continuous renal replacement therapy (CRRT). This study assesses its efficacy in patients admitted to critical care following cardiovascular surgery and the influence of standard antithrombotic agents routinely used in this specific group. METHODS: Consecutive cardiovascular surgery patients treated with postdilution hemofiltration with RCA were included in this prospective observational study. The primary outcome of the study was CRRT circuit life-span adjusted for reasons other than clotting. The secondary outcome evaluated the influence of standard antithrombotic agents (acetylsalicylic acid [ASA], low molecular weight heparin [LMWH] or fondaparinux as thromboprophylaxis or treatment dose with or without ASA) on filter life. RESULTS: Fifty-two patients underwent 193 sessions of continous veno-venous hemofiltration, after exclusion of 15 sessions where unfractionated heparin was administered. The median filter life span was 58 hours. Filter life span was significantly longer in patients receiving therapeutic dose of LMWH or fondaparinux (79 h [2-110]), in comparison to patients treated with prophylactic dose of LMWH or fondaparinux (51 h [7-117], p < 0.001), and patients without antithrombotic prophylaxis (42 h [2-91], p < 0.0001). 12 bleeding episodes were observed; 8 occurred in patients receiving treatment dose anticoagulation, 3 in patients receiving prophylactic dose anticoagulation and 1 in a patient with no antithrombotic prophylaxis. CONCLUSIONS: A postdilution hemofiltration with RCA provides prolonged filter life span when adjusted for reasons other than clotting. Patients receiving treatment dose anticoagulation had a significantly longer filter life span than those who were on prophylactic doses or ASA alone.

COVID-19 - Toward a comprehensive understanding of the disease.

The evidence on the pathophysiology of the novel coronavirus SARS-CoV-2 infection is rapidly growing. Understanding why some patients suffering from COVID-19 are getting so sick, while others are not, has become an informal imperative for researchers and clinicians around the globe. The answer to this question would allow rationalizing the fear surrounding this pandemic. Understanding of the pathophysiology of COVID-19 relies on an understanding of interplaying mechanisms, including SARS-CoV-2 virulence, human immune response, and complex inflammatory reactions with coagulation playing a major role. An interplay with bacterial co-infections, as well as the vascular system and microcirculation affected throughout the body should also be examined. More importantly, a compre-hensive understanding of pathological mechanisms of COVID-19 will increase the efficacy of therapy and decrease mortality. Herewith, presented is the current state of knowledge on COVID-19: beginning from the virus, its transmission, and mechanisms of entry into the human body, through the pathological effects on the cellular level, up to immunological reaction, systemic and organ presentation. Last but not least, currently available and possible future therapeutic and diagnostic options are briefly commented on.

First uses of HAART 300 rings for aortic valve repair in Poland - 4 case studies.

INTRODUCTION: Aortic valve reconstructions using geometric annuloplasty rings HAART 300/200 open new era in aortic valve surgery. The HAART technology resizes, reshapes, stabilizes and simplifies aortic valve repair. The HAART aortic repair rings are designed to be implanted directly into aortic annulus (under aortic valve leaflets). AIM: We present first in Poland 4 cases of aortic valve reconstructions using geometric annuloplasty rings HAART 300. MATERIAL AND METHODS: Two patients had type IA aortic insufficiency (due to El-Khoury classification) - they were treated by HAART 300 ring insertion and ascending aorta prosthesis implantation. Third patient, Marfan with type IB aortic insufficiency was repaired by HAART 300 ring implantation followed by remodeling (Yacoub) procedure. Fourth patient with type II aortic insufficiency (due to RCC prolapse) was repaired by HAART 300 implantation and cusp plication. RESULTS: All patients shows good results on 6 months postoperative 3D TTE examinations. CONCLUSIONS: Presented technique is reproducible and simplify aortic valve reconstructions.

High-volume hemofiltration as adjuvant therapy for refractory shock after pericardiocentesis.

BACKGROUND: Pericardiocentesis for the treatment of chronic cardiac tamponade can occasionally result in acute pulmonary edema or biventricular failure. A sudden increase in heart filling pressures and right-to-left ventricular-output mismatch have been proposed underlying mechanisms. CASE REPORT: We report the case of 16-year-old patient who underwent pericardiocentesis for chronic cardiac tamponade 6 weeks after undergoing a Bentall procedure. The patient developed circulatory shock 6 hours after pericardiocentesis. High-volume hemofiltration was used as a rescue therapy after treatment with positive inotropic drugs proved ineffective. An improvement in circulatory function observed after commencement of the hemofiltration treatment was followed by hemodynamic deterioration when the hemofiltration procedure was ceased. DISCUSSION: The mechanism of the observed hemodynamic improvement is unclear. Hemodynamic recovery related in time to high-volume hemofiltration treatment indicates the possible removal of inflammatory mediators. Visceral vasoconstriction resulting from cardiac tamponade and subsequent improvement in gut perfusion after pericardiocentesis that led to washout of inflammatory mediators might have contributed to the development of acute heart failure. Cytokine removal by high-volume hemofiltration and the procedure's relationship to hemodynamic improvement have previously been demonstrated in clinical and experimental studies of septic shock. CONCLUSIONS: We conclude that high-volume hemofiltration can be helpful as an adjuvant treatment for refractory shock after pericardiocentesis for chronic cardiac tamponade. The mechanism of the observed hemodynamic improvement remains to be investigated.

Incidence- and mortality-related risk factors of acute kidney injury requiring hemofiltration treatment in patients undergoing cardiac surgery: a single-center 6-year experience.

OBJECTIVE: To evaluate the incidence and mortality risk factors of severe acute kidney injury (AKI) requiring hemofiltration treatment after cardiac surgery. DESIGN: A single-center, retrospective, case-control study. SETTING: A post-cardiac-surgical intensive care unit at a university hospital. PARTICIPANTS: Nine thousand two hundred twenty-two consecutive adult cardiac surgical patients, among whom 107 developed severe AKI. INTERVENTIONS: Continuous venovenous hemofiltration. MEASUREMENTS AND MAIN RESULTS: The overall incidence of severe AKI was 1.2%, but it differed with the type of surgical procedure including coronary artery bypass graft surgery, 0.4%; heart valves, 1.7%; aorta surgery, 5.4%; ventricle septum rupture, 52.6%; and other, 6.5%. From 6 predictors of 30-day mortality identified by univariate logistic regression (age, preoperative serum creatinine, New York Heart Association class, resternotomy, postoperative myocardial infarction, and postoperative use of intra-aortic balloon pump [IABP]), only the need for the postoperative use of IABP (odds ratio, 2.9; p = 0.01) and resternotomy (odds ratio, 3.4; p = 0.005) proved stable in multivariate analysis. Kaplan-Meier analysis identified the following overall mortality risk factors: age (p = 0.03), New York Heart Association class ≥II (p = 0.0004), resternotomy (p = 0.02), postoperative myocardial infarction (p = 0.01), and IABP (p = 0.03). CONCLUSIONS: The risk of developing severe AKI depended on the type of cardiac surgical procedure. Thirty-day mortality was associated with severe perioperative circulation impairment or bleeding, but overall long-term mortality was additionally predicted by age, postoperative myocardial infarct, and preoperative circulation status.

Anaesthesia for ophthalmologic surgical procedures in a patient with advanced amyotrophic lateral sclerosis: a case report.

INTRODUCTION: Anaesthesia procedures for surgical interventions in patients with amyotrophic lateral sclerosis (ALS) are not commonly found in clinical practice, and often have special considerations that must be taken into account in treatment planning. As a result, these procedures are rarely subject to publication, rendering it difficult for the anaesthesiologists to find useful and reliable information on this topic. ALS also presents a contraindication to the use of nondepolarising neuromuscular blocking drugs during general anaesthesia. CASE PRESENTATION: In the case presented here, a 52-year old, White man, the progression of the disease to tetraparesis and respiratory failure, in addition to having the patient on chronic mechanical ventilation support, provided additional challenges to the handling team. The maturation of cataracts severely impaired communication with the patient, and surgical treatment of the cataract presented the only means to save communication. Such interventions are generally performed under local anaesthesia with the advice of the attending anaesthesiologist. However, in this case the patients' announcements during the operation would be unreadable to the advising anaesthesiologist. Here, the authors share experiences from a successfully applied combination of topical and general anaesthesia for two cataract operations and a vitrectomy. This was tolerated well by the patient, and without any side-effects. CONCLUSION: The applied treatment resulted in a substantial improvement of the vision and allowed communication to be maintained with the patient.