The use of a numerical model to simulate the cavo-pulmonary assistance in Fontan circulation: a preliminary verification.

The lack of an established experience on the use of VAD for the cavo-pulmonary assistance leads to the need of dedicated VADs development and animal experiments. A dedicated numerical model could support clinical and experimental strategies design and new VADs testing. The aim of this work is to perform a preliminary verification of a lumped parameter model of the cardiovascular system to simulate Fontan physiology and the effect of cavo-pulmonary assistance. Literature data of 4 pigs were used to simulate animals' baseline, and then the model was tested in simulating Fontan circulation and cavo-pulmonary-assisted condition comparing the simulation outcome (Sim) with measured literature data (Me). The results show that the numerical model can well reproduce experimental data in all three conditions (baseline, Fontan and assisted Fontan) [cardiac output (l/min): Me = 2.8 ± 1.7, Sim = 2.8 ± 1.8; ejection fraction (%): Me = 57 ± 17, Sim = 54 ± 17; arterial systemic pressure (mmHg): Me = 41.8 ± 18.6, Sim = 43.8 ± 18.1; pulmonary arterial pressure (mmHg): Me = 15.4 ± 8.9, Sim = 17.7 ± 9.9; caval pressure (mmHg): Me = 6.8 ± 4.1, Sim = 7 ± 4.6]. Systolic elastance, arterial systemic and arterial pulmonary resistances increase (10, 69, and 100 %) passing from the biventricular circulation to the Fontan physiology and then decrease (21, 39, and 50 %) once the VAD was implanted. The ventricular external work decreases (71 %) passing from the biventricular circulation to the Fontan physiology and it increases three times after the VAD implantation in parallel with the VAD power consumption. A numerical model could support clinicians in an innovative and challenging field as the use of VAD to assist the Fontan physiology and it could be helpful to personalize the VAD insertion on the base of ventricular systo-diastolic function, circulatory parameters and energetic variables.

Monitoring prohemostatic treatment in bleeding patients.

Acutely bleeding patients are commonly found in the trauma and major surgery scenarios. They require prompt and effective treatment to restore an adequate hemostatic pattern, to avoid serious and sometimes life-threatening complications.Different prohemostatic treatments are available, including allogeneic blood derivatives (fresh frozen plasma, platelet concentrates, and cryoprecipitates), prothrombin complex concentrates, specific coagulation factors (fibrinogen, recombinant factor XIII, recombinant activated factor VII), and drugs (protamine for patients under heparin treatment, desmopressin, antifibrinolytics).For decades, prohemostatic treatment of the acutely bleeding patient was based on empirical strategies and clinical judgment, both in terms of a correct diagnosis of the mechanism(s) leading to bleeding, and of an assessment of the effects of the treatment. This empirical strategy may lead to excessive or unnecessary use of allogeneic blood products, as well as to an incorrect, inefficacious, or even dangerous treatment. Different monitoring devices are nowadays available for guiding the diagnostic and therapeutic decision-making process in an acutely bleeding patient. This review addresses the available tools for monitoring prohemostatic treatment of the bleeding patient, with a specific respect for point-of-care tests (thromboelastography, thromboelastometry, platelet function tests, and heparin monitoring systems) at the light of the existing evidence.

Imaging and monitoring in minimally invasive valve surgery using an intra-aortic occlusion device: a single center experience.

BACKGROUND: Minimally invasive approach through a right mini-thoracotomy is a world-wide used procedure for mitral valve surgery. We performed a retrospective analysis based on our center experience in order to propose an effective, safe and reproducible method using an intra-aortic occlusion device. METHODS: This is a retrospective analysis on 48 consecutive patients undergoing mitral valve surgery through a right anterolateral mini-thoracotomy in our center. An intra-aortic occlusion device was used for aortic clamping and cardioplegia delivery. Simultaneous multi-plane three-dimensional echocardiography imaging was acquired to detect the venous cannulas position, the intra-aortic device location in the ascending aorta, the balloon inflation, the complete occlusion of the aorta, the cardioplegia delivery, the origin and the blood flow in the right coronary artery. Aortic root pressure was measured by the tip of the intra-aortic occlusion device. A bilateral upper extremity invasive arterial pressure monitoring was detected. Neuromonitoring was performed through bilateral cerebral oximetry. RESULTS: The analysis has shown no aortic dissection, neurological damage type 1 and myocardial ischemia in the study population. In 3 cases a distal displacement of the intra-aortic occlusion device was promptly detected by the combined use of echocardiographic imaging and by a drop of the right cerebral oximetry saturation and of the right radial artery pressure. CONCLUSIONS: The combined use of transesophageal simultaneous multi-plane three- dimensional echocardiography imaging, bilateral upper extremity invasive arterial pressure monitoring, aortic root pressure and cerebral oximetry is an effective, safe and reproducible method in patients undergoing minimally invasive valve surgery using an intra-aortic occlusion device.

Ascending aorta pseudoaneurysm simulating mediastinal lymphoma in computed tomography, a possible diagnostic error: a case report.

BACKGROUND: An ascending aortic pseudoaneurysm is a severe and rare complication following cardiothoracic surgery. This case report demonstrates its possible misinterpretation and the consequent importance of multidisciplinary evaluation. CASE PRESENTATION: We present a case of an 18-year-old Caucasian man with Marfan syndrome who developed an ascending aortic pseudoaneurysm about 1 year after undergoing cardiac surgery with the Bentall procedure. Computed tomographic examination of the thoracic aorta and positron emission tomography-computed tomography initially suggested a lymphomatous pathology. However, these imaging results were in contrast to the transesophageal echocardiogram and the laboratory data that showed negative results for hematological pathology. A second computed tomographic scan redirected the diagnosis toward a pseudoaneurysm. CONCLUSION: This case demonstrates the utility of close communication and interdisciplinary consultation between cardiovascular radiologists and the cardiac surgery team, which are mandatory in order to maximize their diagnostic skills in identifying postoperative complications.

Cold crystalloid versus warm blood cardioplegia in patients undergoing aortic valve replacement.

BACKGROUND: Myocardial protection techniques during cardiac arrest have been extensively investigated in the clinical setting of coronary revascularization. Fewer studies have been carried out of patients affected by left ventricular hypertrophy, where the choice of type and temperature of cardioplegia remain controversial. We have retrospectively investigated myocardial injury and short-term outcome in patients undergoing aortic valve replacement plus or minus coronary artery bypass grafting with using cold crystalloid cardioplegia (CCC) or warm blood cardioplegia (WBC). METHODS: From January 2015 to October 2016, 191 consecutive patients underwent aortic valve replacement plus or minus coronary artery bypass grafting in normothermic cardiopulmonary bypass. Cardiac arrest was obtained with use of intermittent antegrade CCC group (n=32) or WBC group (n=159), according with the choice of the surgeon. RESULTS: As compared with WBC group, in CCC group creatine-kinase-MB (CK-MB), cardiac troponin I (cTnI), aspartate aminotransferase (AST) release, and their peak levels, were lower during each time points of evaluation, with the greater statistically significant difference at time 0 (P<0.05, for all comparisons). A time 0, CK-MB/CK ratio >10% was 5.9% in CCC group versus 7.8% in WBC group (P<0.0001). At time 0 CK-MB/CK ratio >10% in patients undergoing isolated aortic valve replacement was 6.0% in CCC group versus 8.0% in WBC group (P<0.01). No any difference was found in perioperative myocardial infarction (0% versus 3.8%), postoperative (PO) major complications (15.6% versus 16.4%), in-hospital mortality (3.1% versus 1.3%). CONCLUSIONS: In aortic valve surgery a significant decrease of myocardial enzymes release is observed in favor of CCC, but this difference does not translate into different clinical outcome. However, this study suggests that in presence of cardiac surgical conditions associated with significant left ventricular hypertrophy, i.e., the aortic valve disease, a better myocardial protection can be achieved with the use of a cold rather than a warm cardioplegia. Therefore, CCC can be still safely used.

An Unexpected Risk Factor for Early Structural Deterioration of Biological Aortic Valve Prostheses.

BACKGROUND: An alarming rate of early failure has been recently reported for the LivaNova (previously Sorin) Mitroflow (LivaNova, London, UK) bioprosthesis. Here, we aimed at verifying if this possible underperformance is confirmed in a large, single-center experience and identifying the risk factors associated with early deterioration. METHODS: In all, 459 Mitroflow valves have been implanted from July 2009 to December 2013 (patients' mean age 73 years; 204 women). Surviving patients have undergone yearly clinic and echocardiographic follow-up. Dysfunction was defined as moderate if the mean gradient was more than 30 mm Hg or severe if it exceeded 40 mm Hg. The population was divided on the basis of a dimensional mismatch, the model of the prosthesis (LX or DL: follow-up to 4 years), and patient's age at the time of implantation. RESULTS: Cumulative freedom from moderate valve dysfunction was 81% ± 3% at 60 months. It was lower with patient-prosthesis mismatch (71% ± 5% versus 92% ± 3%; p = 0.0065) and with the more recent DL model (at 42 months: 78% ± 6% versus 96% ± 2%; p < 0.0001). Cumulative freedom from severe dysfunction was 93% ± 2% at 5 years. Again, it was inferior among patients with a mismatch (86% ± 4% versus 100%; p = 0.0013) and for the DL model (42 months: 92.5% ± 3% versus 98.5% ± 1%; p = 0.0309). Smaller prostheses showed higher rates of early degeneration. CONCLUSIONS: The LivaNova Mitroflow valve appears to be prone to early deterioration. Smaller size prostheses should be used cautiously and avoided with patient-prosthesis mismatch. The DL model anticalcification treatment seems unable to prevent early degeneration, and possibly contributes to even earlier failure.

Fibrinogen Levels After Cardiac Surgical Procedures: Association With Postoperative Bleeding, Trigger Values, and Target Values.

BACKGROUND: Low fibrinogen levels immediately after cardiac surgical procedures have been associated with postoperative bleeding and transfusions. However, no sound data on the adequate trigger values for fibrinogen supplementation and target values for fibrinogen concentration exist. METHODS: This retrospective study examined prospectively collected data, including data on 2,800 adult patients undergoing cardiac operations. Standard coagulation parameters at the arrival in the intensive care unit were retrieved, inclusive of fibrinogen levels. Postoperative bleeding was assessed based on the chest drain output (mL/12 h). Severe bleeding (SB) was defined as chest drain output greater than 1,000 mL/12 h. RESULTS: Postoperative blood loss was associated with low values of fibrinogen and platelet count, as well as with a prolonged activated partial thromboplastin time and international normalized ratio. At multivariable analysis, fibrinogen levels lower than 220 mg/dL remained independently associated with SB (odds ratio: 2.25; 95% confidence interval: 1.54 to 3.28). A cutoff value of 115 mg/dL yielded a positive predictive value for SB of 50% and may be proposed as a trigger value for fibrinogen supplementation, with a target value of 280 mg/dL (98% negative predictive value for SB). In actively bleeding patients, these values are increased to 215 and 375 mg/dL, respectively. CONCLUSIONS: These data confirm the independent role of fibrinogen levels as determinants of SB after cardiac surgical procedures and suggest adequate cutoff values and fibrinogen concentrate doses to prevent or treat SB. However, the identified trigger and target values should be confirmed in prospective series of patients undergoing fibrinogen supplementation.

Safety and efficacy of citrate anti-coagulation continuous renal replacement therapies in post-cardiac surgery patients with liver dysfunction.

The study's aim was to examine safety and efficiency of citrate anticoagulated continuous renal replacement therapies (CRRT) in cardiac surgery patients with acute kidney injury and associated liver dysfunction. The study was conducted on critical ICU patients, hospitalized after cardiac surgery, who developed renal and liver acute failures due to low-flow syndrome. CRRT in continuous veno-venous hemodiafiltration with regional citrate anticoagulation (RCA) was prescribed to address renal failure and avoid bleeding-risk. Patient Ca(++) was measured to monitor RCA safety, while thromboelastography (TEG) and circuit Ca(++) were used to verify efficacy. CRRT effectiveness was evaluated through creatinine and urea levels, while liver function was monitored through bilirubin, aspartate aminotransferase, glutamic oxaloacetic transaminase (AST GOT) and gamma glutamyl transferase (GT) levels. The study did not require ethical approval. Hepatic and renal failures were confirmed by baseline levels (total bilirubin=3.1 ± 3.37 mg/dL, AST GOT=153 ± 147 U/L and gamma GT=93.3 ± 86 IU/L, creatinine=1.97 ± 0.88 and blood urea nitrogen [BUN] 98.13 ± 71.34) assessed in 15 patients. During treatment, Ca(++) (patient and circuit) remained stable and within range for the whole therapy thanks to low citrate dose (2.8 ± 0.3 mmol/L of blood), while hepatic markers did not show any significant changes the therapy, although treatment with citrate is contraindicated in patients with hepatic failure. RCA quality was confirmed by TEG values, which showed an anticoagulated circuit with no effects on patients. These results involved a high filter lifespan (49.76 ± 22.10 h) and with an effective creatinine and BUN clearance. No episodes of citrate intoxication were reported (total/ionized calcium ratio remained stable and physiologic). RCA during CRRT with dilute solutions proved both effective and safe, even in patients with acute liver failure.

One-year appraisal of a new aortic root conduit with sinuses of Valsalva.

OBJECTIVES: We evaluate the clinical results 1 year after an anatomic reconstruction of the aortic root in which we used a specifically designed aortic root prosthesis that incorporates the sinuses of Valsalva. MATERIAL AND METHODS: The new aortic Dacron prosthesis has a proximal portion in the Dacron conduit that expands on implantation, creating pseudosinuses. During a 12-month period, 28 patients (mean age 59 +/- 14 years) underwent a Bentall operation (12 cases), a remodeling procedure (7 cases), and a reimplantation procedure (9 cases) with the use of a new aortic root conduit. All patients had aortic root aneurysm with an anatomically normal (for the valve-sparing procedure) or diseased aortic valve (for the Bentall operation). Five patients had aortic dissection and 5 had Marfan disease. The mean follow-up was 6 +/- 3 months. All patients underwent postoperative transesophageal and transthoracic echocardiographic studies. RESULTS: All patients survived and were in good clinical condition at the latest follow-up. Postoperative echocardiography showed a marked reduction in ventricular volumes in all patient groups (P <.0005). In the Bentall group the new prosthesis appeared to reduce the tension on the coronary ostial sutures. In patients undergoing both types of valve-sparing procedures a similar normal anatomy of the aortic root was reconstructed. In the reimplantation group the anulus was smaller than in the remodeling group (P =.01). Patients undergoing the reimplantation procedure had less bleeding and a lower incidence of residual valve insufficiency. CONCLUSIONS: The new aortic root prosthesis allowed the reconstruction of the aortic root anatomy in all types of surgical techniques with low postoperative morbidity.

Long-term outcome of coronary artery bypass grafting in patients with left ventricular dysfunction.

BACKGROUND: Coronary artery bypass grafting (CABG) is a well-accepted therapeutic strategy for patients with multivessel coronary artery disease and left ventricular dysfunction. The aim of the study was to evaluate long-term results after CABG in patients with preoperative left ventricular ejection fraction (LVEF) of 0.35 or less. METHODS: Data from 302 consecutive patients (mean age, 62 +/- 8.7 years) with LVEF of 0.35 or less who had undergone CABG were analyzed. Epinephrine and enoximone with or without norepinephrine were used to increase cardiac index. Intra-aortic balloon pump or left ventricular assist devices, or both, were used in case of postoperative low output syndrome. RESULTS: Complete revascularization was achieved in 298 of 302 patients (98.7%); internal thoracic artery was used in 294 (97.4%). Operative mortality was 5.3%; independent predictors of operative mortality were emergency CABG (p = 0.005), history of ventricular arrhythmias (p = 0.007), and previous anterior myocardial infarction (p = 0.05). At follow-up, all-cause mortality was 30.8%, and 10-year survival was 63% +/- 4%; independent predictors of late all-cause mortality were history of ventricular arrhythmias (p < 0.0001), chronic renal dysfunction (p = 0.0004), and diabetes mellitus (p = 0.04). Cardiac death was 20.4%, and 10-year freedom from cardiac death was 73% +/- 3.3%; independent predictors of cardiac death were history of ventricular arrhythmias (p = 0.004), chronic renal dysfunction (p = 0.03), and more than one previous anterior myocardial infarction (p = 0.004). At 80 +/- 44 months of follow-up, echocardiography showed significant LVEF improvement (0.43 +/- 0.09 versus 0.28 +/- 0.06, p < 0.0001). Ten-year freedom from myocardial infarction was 87% +/- 3%. CONCLUSIONS: Excellent long-term results after CABG can be expected for patients with LVEF of 0.35 or less. Complete revascularization and internal thoracic artery grafting are associated with high freedom from myocardial infarction. Careful treatment of arrhythmias, diabetes, and renal dysfunction is necessary to improve long-term survival.