Avaliação ecocardiográfica da função do ventrículo direito após cirurgia cardíaca com circulação extracorporal

Mestrado em Tecnologia de Diagnóstico e Intervenção Cardiovascular - Ramo de especialização: Ultrassonografia Cardiovascular

Cirurgias de Derivação do Ventrículo Pulmonar

Cavopulmonary connections have been extensively used in the palliation of complex forms of congenital heart disease requiring some form of right heart bypass. We examine the mid term outcomes of pulmonary ventricle bypass operations in a single institution and performed by the same surgical team. POPULATION: Between March 1999 and April 2006, 62 patients underwent pulmonary ventricle bypass operations: bidirectional cavopulmonary anastomosis (Glenn procedure), total cavopulmonary connections (Fontan procedure) and one and a half ventricle correction in two cases. Age at operation averaged three years (range: 0.42-25 years) for the Glenn procedure and seven years (range: 3-14 years) for the Fontan procedure. There were 36 male patients (58%) and 26 female patients (42%). The most common indication for surgery was the single ventricle defect, present in 66% of patients. Associated lesions included: transposition of the great arteries in 16 patients (35.6%), bilateral superior vena cava in four patients (8.9%), situs ambigus in five patients (11%), situs inversus in another patient (2.2%), Ebstein disease in one patient (2.2) and coronary fistula in another patient (2.2%). Sub-aortic stenosis was present in one patient (2.2%). Palliative surgery was performed in all, but three patients (5%), before the Fontan procedure. RESULTS: Thirty two patients underwent bidirectional cavopulmonary anastomosis and thirty patients underwent cavopulmonary connections, total or 2nd stage. Mean cardiopulmonary bypass times were 50.6+/-21.9 minutes for the Glenn procedure and 88.5+/-26.3 minutes for the Fontan procedure. There was no intra-operative mortality, but two patients (3.2% (died in the first month after surgery; one due to failure of the Glenn circuit and sepsis and the other due to a low cardiac output syndrome and multi-organ dysfunction. Mean ventilation time was 5.2+/-1.7 hours for the Glenn operation and 6.2+/-3.2 hours for the Fontan operation. The mean length of stay in ICU was 3.4+/-2.8 days for patients undergoing the Glenn operation and 4.6+/-3.1 days for patients undergoing the Fontan operation and the mean length of hospital stay was 10.6+/-5.8 days for the Glenn operation and 19.1+/-12.6 days for the Fontan operation respectively. The mean follow up time was 4+/-2.1 years (minimum 0 years and maximum seven years), most patients being in NYHA class I. Epicardiac pacemakers were implanted in three patients due to arrhythmias. Two re-operations (6.7%) were needed, both in the same patient, after the Fontan procedure, this patient eventually died a few years after surgery. CONCLUSIONS: The immediate and mid term outcomes of pulmonary ventricle bypass operations can have excellent results. From our point of view there has been an improvement, namely in the use of the extracardiac conduit technique in the 2nd stage of the Fontan operation.

Unusual abdominal tumors with intracardiac extension. Two cases with successful surgical resection

Abdominal tumors that can grow through vascular lumen and spread to the right heart are rare. Although these tumors have different histologic aspects, they may cause similar abdominal and cardiac symptoms and are a serious risk factor for pulmonary embolism and sudden death when they reach the right atrium and tricuspid valve. The best treatment is radical surgical resection of the entire tumor using cardiopulmonary bypass with or without deep hypothermia and total circulatory arrest. We report the cases of two patients, the first with leiomyosarcoma of the inferior vena cava and the other with intravenous leiomyomatosis of the uterus that showed intravascular growth up to right atrium and ventricle, who underwent successful radical resection in a one-stage procedure with the use of cardiopulmonary bypass. We discuss the clinical and histologic aspects and imaging diagnosis and review the literature.

Assessment of factors that influence weaning from long-term mechanical ventilation after cardiac surgery

OBJECTIVE: To analyze parameters of respiratory system mechanics and oxygenation and cardiovascular alterations involved in weaning tracheostomized patients from long-term mechanical ventilation after cardiac surgery. METHODS: We studied 45 patients in their postoperative period of cardiac surgery, who required long-term mechanical ventilation for more than 10 days and had to undergo tracheostomy due to unsuccessful weaning from mechanical ventilation. The parameters of respiratory system mechanics, oxigenation and the following factors were analyzed: type of surgical procedure, presence of cardiac dysfunction, time of extracorporeal circulation, and presence of neurologic lesions. RESULTS: Of the 45 patients studied, successful weaning from mechanical ventilation was achieved in 22 patients, while the procedure was unsuccessful in 23 patients. No statistically significant difference was observed between the groups in regard to static pulmonary compliance (p=0.23), airway resistance (p=0.21), and the dead space/tidal volume ratio (p=0.54). No difference was also observed in regard to the variables PaO2/FiO2 ratio (p=0.86), rapid and superficial respiration index (p=0.48), and carbon dioxide arterial pressure (p=0.86). Cardiac dysfunction and time of extracorporeal circulation showed a significant difference. CONCLUSION: Data on respiratory system mechanics and oxygenation were not parameters for assessing the success or failure. Cardiac dysfunction and time of cardiopulmonary bypass, however, significantly interfered with the success in weaning patients from mechanical ventilation.

Experience of ECMO in Primary Graft Dysfunction after Orthotopic Heart Transplantation

Background:Primary graft dysfunction is the main cause of early mortality after heart transplantation. Mechanical circulatory support has been used to treat this syndrome.Objective:Describe the experience with extracorporeal membrane oxygenation to treat post-transplant primary cardiac graft dysfunction.Methods:Between January 2007 and December 2013, a total of 71 orthotopic heart transplantations were performed in patients with advanced heart failure. Eleven (15.5%) of these patients who presented primary graft dysfunction constituted the population of this study. Primary graft dysfunction manifested in our population as failure to wean from cardiopulmonary bypass in six (54.5%) patients, severe hemodynamic instability in the immediate postoperative period with severe cardiac dysfunction in three (27.3%), and cardiac arrest (18.2%). The average ischemia time was 151 ± 82 minutes. Once the diagnosis of primary graft dysfunction was established, we installed a mechanical circulatory support to stabilize the severe hemodynamic condition of the patients and followed their progression longitudinally.Results:The average duration of extracorporeal membrane oxygenation support was 76 ± 47.4 hours (range 32 to 144 hours). Weaning with cardiac recovery was successful in nine (81.8%) patients. However, two patients who presented cardiac recovery did not survive to hospital discharge.Conclusion:Mechanical circulatory support with central extracorporeal membrane oxygenation promoted cardiac recovery within a few days in most patients.

Establishing an association between a peri-operative perfusion score system (PerfSCORE) and post-operative patient morbidity/mortality during CPB cardiac surgery.

BACKGROUND: To date, there is no quality assurance program that correlates patient outcome to perfusion service provided during cardiopulmonary bypass (CPB). A score was devised, incorporating objective parameters that would reflect the likelihood to influence patient outcome. The purpose was to create a new method for evaluating the quality of care the perfusionist provides during CPB procedures and to deduce whether it predicts patient morbidity and mortality. METHODS: We analysed 295 consecutive elective patients. We chose 10 parameters: fluid balance, blood transfused, Hct, ACT, PaO2, PaCO2, pH, BE, potassium and CPB time. Distribution analysis was performed using the Shapiro-Wilcoxon test. This made up the PerfSCORE and we tried to find a correlation to mortality rate, patient stay in the ICU and length of mechanical ventilation. Univariate analysis (UA) using linear regression was established for each parameter. Statistical significance was established when p < 0.05. Multivariate analysis (MA) was performed with the same parameters. RESULTS: The mean age was 63.8 +/- 12.6 years with 70% males. There were 180 CABG, 88 valves, and 27 combined CABG/valve procedures. The PerfSCORE of 6.6 +/- 2.4 (0-20), mortality of 2.7% (8/295), CPB time 100 +/- 41 min (19-313), ICU stay 52 +/- 62 hrs (7-564) and mechanical ventilation of 10.5 +/- 14.8 hrs (0-564) was calculated. CPB time, fluid balance, PaO2, PerfSCORE and blood transfused were significantly correlated to mortality (UA, p < 0.05). Also, CPB time, blood transfused and PaO2 were parameters predicting mortality (MA, p < 0.01). Only pH was significantly correlated for predicting ICU stay (UA). Ultrafiltration (UF) and CPB time were significantly correlated (UA, p < 0.01) while UF (p < 0.05) was the only parameter predicting mechanical ventilation duration (MA). CONCLUSIONS: CPB time, blood transfused and PaO2 are independent risk factors of mortality. Fluid balance, blood transfusion, PaO2, PerfSCORE and CPB time are independent parameters for predicting morbidity. PerfSCORE is a quality of perfusion measure that objectively quantifies perfusion performance.

Surgery for ruptured thoracic and thoraco-abdominal aortic aneurysms.

OBJECTIVE: To assess the outcome of patients with ruptured descending thoracic and thoracoabdominal aortic aneurysms undergoing emergency repair, in comparison to elective surgery for chronic lesions. METHODS: A prospective study of 100 consecutive patients operated upon the descending aorta (1-8 segments) using proximal unloading and distal protection with partial cardiopulmonary bypass, heparin surface-coated perfusion equipment and low systemic heparinization (loading dose 100 IU/kg, activated coagulation time > 180 s), staged cross-clamping, sealed grafts and graft inclusion. RESULTS: Arteriosclerotic lesions were present in 53/100 patients (53%) for all, 30/53 (56%) for chronic, and 21/33 (63%) for ruptured, aneurysms (NS). Dissecting lesions were found in 38/100 patients (38%) for all, 20/53 (38%) for chronic, and 8/33 (24%) for ruptured aneurysms (NS). Preoperative hematocrit was 38 +/- 6% for all, 40 +/- 5% for chronic, and 33 +/- 5% for ruptured aneurysmal patients (P < 0.001 ruptured versus chronic). The extent of aortic repair (1-8 segments) was 3.3 +/- 1.6 for all, 3.5 +/- 1.5 for chronic, and 3.2 +/- 1.4 for ruptured, aneurysms (NS). Transdiaphragmatic repair was performed in 51/100 (51%) of all, 28/53 (53%) of chronic, and 17/33 (51%) of ruptured aneurysms (NS). Aortic cross-clamp time was 38 +/- 21 min for all, 39 +/- 24 min for chronic, and 38 +/- 17 min for ruptured, aneurysmal patients (NS). The amount of red cells washed and autotransfused was 2792 +/- 2239 ml in all, 3143 +/- 2531 ml in chronic, and 2074 +/- 1350 ml in ruptured, aneurysmal patients (P < 0.025). The amount of packed red cells required was 2181 +/- 1830 ml for all, 1736 +/- 1333 ml for chronic, and 2947 +/- 2395 ml for ruptured aneurysmal patients (P < 0.010). Thirty-day mortality was 9/100 (9%) for all, 3/53 (6%) for chronic, and 5/33 (15%) for ruptured aneurysmal patients (NS). Parapareses/plegias occurred in 9/100 (9%) of all, 6/53 (11%) of chronic, and 3/33 (9%) of ruptured, aneurysmal patients (NS). Stepwise regression analysis identified aortic cross-clamp time as a predictor of early mortality (P = 0.002) and parapareses and paraplegias (P = 0.001). Age (P = 0.001), extent of repair (P = 0.008) and preoperative hematocrit (P = 0.001) were predictors for homologous transfusion requirements. CONCLUSION: Emergency repair of ruptured descending thoracic and thoracoabdominal aortic aneurysms can be achieved with acceptable results.

Unexpected left ventricular free-wall rupture following an aortic catheter-valve implantation.

Our experience with the Sapien trans-apical aortic valve (Edwards Lifesciences Inc., Irvine, CA, USA) has been straightforward without per-procedural mortality except in 1/16 consecutive cases who developed non-apical haemorrhage early after valve implantation. We describe the case of an 84-year-old female carrying a very high operative risk (logistic EuroScore of 44%), who underwent a trans-apical stent-valve implantation for severe and symptomatic aortic valve stenosis (23 mm). Due to massive blood loss, an emergency sternotomy and cannulation for cardiopulmonary bypass resuscitation were necessary to treat (without success) an unusual and unexpected subaortic left ventricular free-wall rupture that occurred few minutes after the stent-valve positioning and implantation. To the best of our knowledge, this is the first described case of a left ventricular free-wall rupture occurring after an otherwise non-complicated standard catheter-based aortic valve replacement.

Gaslini's tracheal team: preliminary experience after one year of paediatric airway reconstructive surgery.

Background: congenital and acquired airway anomalies represent a relatively common albeit challenging problem in a national tertiary care hospital. In the past, most of these patients were sent to foreign Centres because of the lack of local experience in reconstructive surgery of the paediatric airway. In 2009, a dedicated team was established at our Institute. Gaslini's Tracheal Team includes different professionals, namely anaesthetists, intensive care specialists, neonatologists, pulmonologists, radiologists, and ENT, paediatric, and cardiovascular surgeons. The aim of this project was to provide these multidisciplinary patients, at any time, with intensive care, radiological investigations, diagnostic and operative endoscopy, reconstructive surgery, ECMO or cardiopulmonary bypass. Aim of this study is to present the results of the first year of airway reconstructive surgery activity of the Tracheal Team.Methods: between September 2009 and December 2010, 97 patients were evaluated or treated by our Gaslini Tracheal Team. Most of them were evaluated by both rigid and flexible endoscopy. In this study we included 8 patients who underwent reconstructive surgery of the airways. Four of them were referred to our centre or previously treated surgically or endoscopically without success in other Centres.Results: Eight patients required 9 surgical procedures on the airway: 4 cricotracheal resections, 2 laryngotracheoplasties, 1 tracheal resection, 1 repair of laryngeal cleft and 1 foreign body removal with cardiopulmonary bypass through anterior tracheal opening. Moreover, in 1 case secondary aortopexy was performed. All patients achieved finally good results, but two of them required two surgeries and most required endoscopic manoeuvres after surgery. The most complex cases were the ones who had already been previously treated.Conclusions: The treatment of paediatric airway anomalies requires a dedicated multidisciplinary approach and a single tertiary care Centre providing rapid access to endoscopic and surgical manoeuvres on upper and lower airways and the possibility to start immediately cardiopulmonary bypass or ECMO.The preliminary experience of the Tracheal Team shows that good results can be obtained with this multidisciplinary approach in the treatment of complicated cases. The centralization of all the cases in one or few national Centres should be considered.

Initial clinical experience with the admiral oxygenator combined with separated suction.

The Admiral, a new microporous membrane oxygenator with a low surface area, decreased priming volume and two separate reservoirs, was tested in 30 adult patients. This study was undertaken to evaluate blood path resistance, gas exchange capabilities and blood trauma in clinical use, with and without shed blood separation. Patients were divided into 3 groups. Group 1 had valve surgery without separation of suction, Group 2 had coronary artery bypass grafting (CABG) with direct blood aspiration and Group 3 had coronary artery bypass grafting with shed blood separation. The suctioned, separated, cardiotomy blood in Group 3 was treated with an autotransfusion device at the end of bypass before being returned to the patient. Theoretical blood flow could be achieved in all cases without problem. The pressure drop through the oxygenator averaged 88 +/- 13 mmHg at 4 l/min and 109 +/- 12 mmHg at 5 l/min. O(2) transfer was 163 +/- 27 ml/min. Free plasma haemoglobin rose in all groups, but significantly less in group 3. Lactate dehydrogenase (LDH) rose significantly in Groups 1 and 2. Platelets decreased in all groups without significant differences. Clinical experience with this new oxygenator was safe, the reduced membrane surface did not impair gas exchange and blood trauma could be minimized easily by separating shed blood, using the second cardiotomy reservoir.

Could Hyperglycaemia and Troponin I predict outcome in intensive care after congenital heart surgery in children?

Objective: To establish if hyperglycaemia and cardiac Troponin I (cTnI) after congenital heart surgery on cardiopulmonary bypass in children could predict outcome in intensive care unit. Methods: retrospective cohort study including 274 children (mean age 4.6 years; range 0 - 17 years-old). CTnI and glucose values were retrieved from our database. Integrated values (area under the curve (AUC)) were calculated for evaluation of sustained hyperglycaemia and then normalised per hour (48h-Gluc/h). Maximal cTnI, fi rst glucose value (Gluc1) and 48h-Gluc/h were then correlated with duration of mechanical ventilation, ICU stay and mortality using cut-off values. Results: The mean duration of mechanical ventilation was 5.1 ± 7.2 days and ICU stay was 11.0 ± 13.3 days, 11 patients (3.9%) died. Hyperglycaemia (>6.1 mmol/l) was present in 68% of children at admission and was sustained in 85% for 48 hours. The mean value of Gluc1 (7.3 ± 2.7 vs. 11.8 ± 6.4 mmol/l, p < 0.0001), 48h-Gluc/h (7.4 ± 1.4 vs. 9.9 ± 4.6 mmol/l/h, p < 0.0001) and cTnI max (16.7 ± 21.8 vs. 59.2 ± 41.4 mcg/l, p < 0.0001) were signifi cantly lower in survivors vs. non survivors. Cut-off values and odds ratio are summarised in Table 1. Analyses for duration of mechanical ventilation and for length of stay in ICU are depicted in Table 2. Conclusions: Hyperglycaemia is frequent after cardiopulmonary bypass and sustained in the fi rst 48 hours. Admission glycaemia and cTnI max are associated with a high risk of mortality, prolonged duration of mechanical ventilation and prolonged length of stay in ICU.

New bench test for venous cannula performance assessment.

Cannula design is of prime importance for venous drainage during cardiopulmonary bypass (CPB). To evaluate cannulas intended for CPB, an in vitro circuit was set up with silicone tubing between the test cannula encased in a movable preload reservoir and another static reservoir. The pressure-drop (DeltaP) value (P-drainage - P-preload) was measured using Millar pressure transducers. Flow rate (Q) was measured using an ultrasound flowmeter. Data display and data recording were controlled using a LabView application, custom made particularly for our experiments. Our results demonstrated that DeltaP, Q, and cannula resistance (DeltaP/Q) values were significantly decreased when the cannula diameter was increased for Smart and Medtronic cannulas. Smartcanula showed 36% and 43% less resistance compared to Medtronic venous and Medtronic femoral cannulas, respectively. The cannula shape (straight- or curved-tips) did not affect the DLP cannula resistance. Out of five cannulas tested, the Smartcanula outperforms the other commercially available cannulas. The mean (DeltaP/Q) values were 3.3 +/- 0.08, 4.07 +/- 0.08, 5.58 +/- 0.10, 5.74 +/- 0.15, and 6.45 +/- 0.15 for Smart, Medtronic, Edwards, Sarns, and Gambro cannulas, respectively (two-way ANOVA, p < 0.0001). In conclusion, the present assay allows discrimination between different forms of cannula with high or low lumen resistance.

Numerical simulation of left ventricular assist device implantations: comparing the ascending and the descending aorta cannulations.

In this work we present numerical simulations of continuous flow left ventricle assist device implantation with the aim of comparing difference in flow rates and pressure patterns depending on the location of the anastomosis and the rotational speed of the device. Despite the fact that the descending aorta anastomosis approach is less invasive, since it does not require a sternotomy and a cardiopulmonary bypass, its benefits are still controversial. Moreover, the device rotational speed should be correctly chosen to avoid anomalous flow rates and pressure distribution in specific location of the cardiovascular tree. With the aim of assessing the differences between these two approaches and device rotational speed in terms of flow rate and pressure waveforms, we set up numerical simulations of network of one-dimensional models where we account for the presence of an outflow cannula anastomosed to different locations of the aorta. Then, we use the resulting network to compare the results of the two different cannulations for several stages of heart failure and different rotational speed of the device. The inflow boundary data for the heart and the cannulas are obtained from a lumped parameters model of the entire circulatory system with an assist device, which is validated with clinical data. The results show that ascending and descending aorta cannulations lead to similar waveforms and mean flow rate in all the considered cases. Moreover, regardless of the anastomosis region, the rotational speed of the device has an important impact on wave profiles; this effect is more pronounced at high RPM.

Therapy of acute massive pulmonary embolism associated with Klippel-Trenaunay syndrome.

Acute massive pulmonary embolism (PE) is a life-threatening event. Before the era of cardiopulmonary bypass, acute pulmonary embolectomy had been historically attempted in patients with severe hemodynamic compromise. The Klippel-Trenaunay syndrome (KTS) represents a significant life-long risk for major thromboembolic events. We present two young patients with Klippel-Trenaunay syndrome who survived surgical embolectomy after massive PE and cardiopulmonary resuscitation, with good postoperative recovery. Even though the role of surgical embolectomy in massive PE is not clearly defined, with current technology it can be life saving and can lead to a complete recovery, especially in young patients as described in this study.