Novel approach to mitral valve repair in childhood dilated cardiomyopathy.

Evidence is mounting that mitral valve repair can improve symptoms in adults with dilated cardiomyopathy. Data is currently lacking for children with dilated cardiomyopathy and options for annuloplasty are limited in children. We report on the successful management of a 21 month-old child in heart failure from dilated cardiomyopathy and severe mitral regurgitation. The echocardiogram showed severely dilated left heart cavities, severe mitral regurgitation from a dilated annulus (23 mm, Z-score 1.74) with discrete anterior leaflet tethering, and moderate systolic dysfunction. The mitral valve was repaired using a 16 mm Bioring Kalangos biodegradable annuloplasty ring. The patient was extubated on the third postoperative hour and discharged on the fifth postoperative day with trivial mitral regurgitation and a 5 mmHg mean transvalvular gradient. At 12 months, the patient is in NYHA class I and presents trivial central mitral regurgitation without any transmitral gradient. This represents the first report in successfully managing a child with dilated cardiomyopathy with mitral regurgitation using a novel biodegradable annuloplasty ring, which has the potential to durably remodel the mitral annulus and grow with the patient.

Primary cardiac lymphoma causing right atrial occlusion.

Primary cardiac lymphomas (PCL) are extremely rare, and diffuse large B-cell lymphoma is a highly aggressive subtype. We report a case that was initially diagnosed as chronic right heart dysfunction. Detailed investigations revealed a large lobulated tumour occluding the right atrium, infiltrating the inter-atrial septum, the roof of the left atrium, and the aortic root. Despite adequate surgical debulking and initial successful tricuspid annuloplasty, the patient succumbed to multi-organ failure. Pathological analysis of the resected tumour confirmed a diffuse large B-cell lymphoma with a proliferation rate of 100%. What is unique about this case is the size of this rare cardiac tumour, which we believe to be one of the largest described in the literature for a purely intra-cardiac PCL, its aggressive growth rate, and the relatively mild symptomatology until a late stage of the disease.

Complex aortic coarctation, regurgitant bicuspid aortic valve with VSD and ventricular non-compaction: a challenging combination.

Left ventricular non-compaction is a myocardial disorder characterized by excessive trabeculations and deep recesses that communicate with the ventricular cavity, which is thought to result from a failure of the trabecular regression that occurs during normal embryonic development. It carries a high mortality from heart failure or sudden cardiac death. A 15-year-old female patient was referred to our institution for moderate symptoms of heart failure. Echocardiography and MRI showed a bicuspid aortic valve with severe regurgitation, subaortic VSD, dilated left ventricle and left ventricular non-compaction with a moderately decreased ejection fraction, as well as isthmic coarctation and transverse arch hypoplasia. We elected to perform transaortic VSD closure and aortic valve replacement using a mechanical prosthetic valve on an arrested heart, and to address aortic coarctation and transverse arch hypoplasia using an extra-anatomic ascending-to-descending aorta bypass. Aortic cross-clamping was limited to 41 minutes. The postoperative recovery was rapid and the girl was discharged in NYHA class I with an estimated LVEF of 39%. Although management must be individualized, extra-anatomic bypass is a good single-stage approach for patients with complex coarctation and concomitant cardiovascular or myocardial disorders, reducing ischemic time and offering a better chance of successful weaning from cardiopulmonary bypass.

[When the heart and/or the lung fails: the ECMO]. / Quand le coeur et/ou les poumons défaillent: oxygénation extracorporelle par "ECMO".

The Extra corporeal membrane oxygenation (ECMO) was initially proposed as a technique of respiratory support using an external membrane oxygenator. With time, it has also become a technique of cardiorespiratory support to ensure both gas exchange and organ perfusion until the restoration of organs function. This technical assistance can be central or peripheral and provides a partial or total circulatory support. The circuit includes a non occlusive centrifugal pump, an oxygenator for an enrichment of O2 and elimination of CO2 and cannulas for drainage and re-injection. Recently, the establishment of such assistance became possible percutaneously, allowing it to be initiated at the intensive care bedside or even before in-hospital admission.

Respiratory distress after surgery of RVOT pathologies: a word of caution on pseudoaneurysm development.

Pseudoaneurysm of the right ventricle outflow tract (RVOT) is a rare complication in pediatric cardiac surgery. We report a patient who developed a right ventricular pseudoaneurysm 8 months after RVOT enlargement using a pericardial patch for infundibular pulmonary stenosis. Our patient was born with severe pulmonary valvular stenosis and treated with percutaneous balloon valvotomy in the neonatal period. Six months later, she developed infundibular pulmonary stenosis, which required surgical resection of right ventricle infundibular trabeculations and bovine pericardial patch enlargement. The postoperative period was normal. She was readmitted to hospital 5 months later complaining of wheezing, coughing and shortness of breath. Echocardiography showed a huge aneurysmal dilatation of the outflow patch in connection with the right ventricular cavity. The patient underwent resection of the pseudoaneurysm and former patch, followed by interposition of a bovine jugular vein conduit between the RVOT and pulmonary bifurcation. The early postoperative period was uncomplicated. On echocardiography, no significant residual gradient was measured through the conduit and there was no insufficiency of the valve. RVOT reconstruction with patch enlargement, homograft or conduit implantation can be the origin of pseudoaneurysms. Although their incidence is rare, they are often asymptomatic before becoming quite large and causing compression symptoms as in our patient with respiratory complaints due to airway compression. It is important to follow up these patients closely, especially in the first year after surgery since most aneurysms develop within 6 months of surgery.

Vascular ultrasound studies for the non-invasive assessment of vascular flow and patency in experimental surgery in the pig.

Vascular ultrasound is a reliable non-invasive tool used for the routine assessment of vascular flow and patency in human recipients. We describe the use at three different time points (immediately, 1 week and 4 weeks postsurgery) of ultrasound studies and its validation by angiographic studies in 37 swine undergoing carotid graft replacement. We calculated predictive values (>92%), sensitivity (>85%) and specificity (>92%) with high results at all time points. Ultrasound appeared as an accessible non-invasive technique, providing rapid, safe, repeatable and reliable results. It is an excellent alternative to angiography, avoiding risks inherent to invasive methods and therefore contributing to animal welfare.

Use of extracorporeal circulation and selective renal perfusion during the surgical correction of abdominal aortic coarctation.

Coarctation of the abdominal aorta is a rare pathology. Stenosis of visceral and renal arteries may present together with coarctation, which requires specific operation techniques. We present the case of a patient with coarctation of the abdominal aorta associated with stenosis of the celiac trunk, the superior mesenteric and the right renal arteries. Distal aortic perfusion by extracorporeal circulation and selective right renal perfusion techniques were used during the operation to protect the spinal cord and kidney against hypoperfusion and ischemia.

Matching the diameter of ePTFE bypass prosthesis with a native artery improves neoendothelialization.

BACKGROUND AND AIM: The undersizing of the bypass graft diameter compared to native artery changes blood flow characteristics and velocity which may affect conduit neo-endothelialization, intimal hyperplasia reaction and patency. The aim of this study was to evaluate conduit neoendothelialization, intimal hyperplasia reaction and patency results between undersized and matched ePTFE grafts. MATERIAL AND METHODS: In 16 male Sprague-Dawley rats, undersized (1-mm internal diameter) and matched (2-mm internal diameter) ePTFE grafts were anastomosed end-to-end in the infrarenal abdominal aorta. Blood flow volume per minute was measured and wall shear stress was calculated for each group. After 3 weeks of follow-up, angiography was performed via the left carotid artery just before sacrifice. Conduit neoendothelialization and intimal hyperplasia reaction were measured by computer-assisted morphometry. RESULTS: Wall shear stress was 8 times higher for the undersized group (840.56 vs. 105.07 mPa). Three weeks after implantation, conduit neoendothelialization was better in matched grafts compared to undersized grafts (441 vs. 574 microm, p = 0.008). Intimal hyperplasia reaction was similar for both groups (8.7 vs. 6.7 microm(2)/microm for undersized and matched grafts, respectively). Patency rate was 7/8 for undersized and 8/8 for matched ePTFE grafts. CONCLUSION: Although the graft patency and the intimal hyperplasia reaction were not different between the two groups after 3 weeks, matched grafts had a significantly better endothelialization compared to undersized grafts. This short-term beneficial effect may influence long-term patency results.

Mitral tendon prolapsing into the left ventricular outflow tract.

Intracardiac masses of the mitral valve are rare. Their differential diagnosis is wide, ranging from tumors (myxomas, lipomas and fibroelastomas), thrombi and abnormal muscular or fibrous bands. We report a case and management. A 68 year-old asymptomatic female who had undergone coronary angioplasty and stent placement in the left anterior descending artery for acute myocardial infarction four years earlier, was shown to have, on routine follow-up, an intracardiac mass originating from the anterior leaflet of the mitral valve and prolapsing into the left ventricular outflow tract (LVOT). The patient underwent surgical excision of the mass under cardiopulmonary bypass, to prevent cerebral or coronary embolization and sudden death due to the highly sensitive location of the mass, in the high-velocity flow LVOT. A transverse aortotomy provided exposure of the ventricular surface of the anterior mitral leaflet and revealed a fusiform mass attached to the medial segment of the anterior leaflet, resembling a secondary cordae, measuring 20 by 3 mm. The implantation was calcified on the ventricular aspect of the anterior mitral leaflet. This mass was completely excised. Postoperative recovery was uneventful. Peroperative and postoperative transesophageal echocardiography were normal. Histological examination showed a partially necrosed and calcified fibrous tissue lined by endothelium. The final diagnosis was that of a mitral tendon. Intracardiac masses of the mitral valve are rare lesions, mostly papillary fibroelastomas and myxomas and more rarely mitral tendons, which require surgical resection for prevention of embolization. The definitive diagnosis is often only obtained on histological analysis.

Improved neo-endothelialization of small diameter ePTFE grafts with titanium coating.

BACKGROUND: Patency of small synthetic bypass grafts is inferior compared to autologous grafts for revascularization procedures. Titanium coating of foreign surfaces has shown to decrease thrombogenicity, enhance biocompatibility and promote adhesion of endothelial cells. The aim of this study was to test the effect of titanium coating of small diameter ePTFE grafts on short term patency, neo-endothelialization and neointimal proliferation. METHODS: Bilateral carotid graft interposition was performed in 5 pigs with uncoated (n=5) and titanium-coated (n=5) ePTFE grafts (internal diameter=4 mm, length=5 cm), thus each pig served as its own control. At the end of the study (30 +/- 3 days), patency and stenosis severity was assessed by carotid angiography. Animals were sacrificed and grafts were excised for histology and scanning electron microscopy. Morphometry of histologic sections was carried out to determine neointimal proliferation and percentage of neo-endothelial coverage. RESULTS: Patency rate was 80% for uncoated and titanium-coated grafts. Quantitative angiography did not show any significant difference in lumen size between two groups. Morphometry revealed a significantly higher cellular coverage with CD31 positive endothelial cells for titanium-coated (84 +/- 19%) than uncoated grafts (48 +/- 26%, p<0.001). There was a non significant trend (p=0.112) towards increased neointimal proliferation in titanium-coated (94 +/- 61 micron2/micron) compared to uncoated grafts (60 +/- 57 micron2/micron). CONCLUSIONS: Patency rate in uncoated and titanium-coated ePTFE grafts is similar at one month. However, titanium coated grafts show a significant improvement in neo-endothelialization compared to uncoated grafts.

PPS-PEG surface coating to reduce thrombogenicity of small diameter ePTFE vascular grafts.

AIMS: Patency failure of small vascular synthetic grafts is still a major problem for coronary and peripheral revascularization. Thus, three new surface coatings of small synthetic grafts were tested in an acute pig model to evaluate their thrombogenicity (extracorporeal arterio-venous shunt) and in a chronic rat model to evaluate the tissue reaction they induced (subcutaneous implantation). METHODS: In five domestic pigs (25-30 kg) an extracorporeal femoro-femoral arterio-venous shunt model was used. The study protocol included first a non-heparinized perfusion sequence followed by graft perfusion after 10,000 UI iv heparin. Grafts were perfused for 3 and 9 minutes. The following coatings were tested on ePTFE grafts: poly-propylene sulphide (PPS)--poly-ethylene glycol (PEG) (wet and dry applications) as well as carbon. Two sets of control were used, one dry and one wet (vehicle only). After perfusion grafts were examined by scanning electron microscopy for semi-quantitative assessment (score 0-3) of cellular and microthrombi deposition. To assess tissue compatibility, pieces of each material were implanted subcutaneously in 16 Wistar rats. At 2, 4, 8, 12 weeks four animals each were sacrificed for semi-quantitative (score 0-3) histologic evaluation of tissue reaction. RESULTS: In the pig model, cellular deposition and microthrombi formation increased over time. In non- heparinized animals, the coatings did not improve the surface characteristics, since they did not prevent microthrombi formation and cellular deposition. In heparinized animals, thrombogenicity was lowest in coated grafts,especially in PPS -PEG dry (p<0.05), and highest in controls. Cell deposition was lowest in PPS-PEG dry, but this difference was not statistically significant vs.controls. In the rat model,no significant differences of the tissue reaction could be shown between materials. CONCLUSION: While all coatings failed to add any benefit for lowering tissue reaction, surface coating with PPS -PEG (dry application) reduced thrombogenicity significantly (in heparinized animals) and thus appears to be promising for improving graft patency of small synthetic vascular prostheses.

The importance of aprotinin and pentoxifylline in preventing leukocyte sequestration and lung injury caused by protamine at the end of cardiopulmonary bypass surgery.

BACKGROUND: Protamine has adverse effects on pulmonary gas exchange during the postoperative period. The objective of this study was to investigate the importance of aprotinin and pentoxifylline in preventing the leukocyte sequestration and lung injury caused by protamine administered after the termination of cardiopulmonary bypass (CPB). METHODS: Participants (n = 39) were allocated into three groups at the termination of CPB: Group 1, (control group, n = 16); Group 2 (aprotinin group, n = 12), who received protamine + aprotinin (15,000 IU/kg); and Group 3 (Pentoxifylline group, n = 11), who received protamine + pentoxifylline (10 mg/kg). Leukocyte counts in pulmonary and radial arteries were determined after the termination of CPB and before any drug was given (t1), and 5 minutes (t2), 2 hours (t3), 6 hours (t4) and 12 hours (t5) after the administration of protamine. Alveolar-arterial O2 gradient (A-aO2) and dynamic pulmonary compliance were measured at t1, t2 and t3. RESULTS: In the control group, an increase in pulmonary leukocyte sequestration was observed 5 minutes and 2 hours after protamine administration, after which this difference disappeared. No significant degree of pulmonary sequestration was detected in any measurements after protamine was administered in the aprotinin and pentoxifylline (PTX) groups. Dynamic lung compliance was 50.1, 45.2 and 47.2 ml/cm H2O in the control group, 49.2, 61.1 and 56.3 ml/cm H2O in the aprotinin group, and 49.5, 54.5 and 50.4 ml/cm H2O in the PTX group. The A-aO2 gradient was 212.2, 263.3 and 254.3 mm Hg in the control group, 209.4, 257.1 and 217.3 mm Hg in the aprotinin group, and 211.3, 260.8 and 219.2 mm Hg in the PTX group. CONCLUSION: Aprotinin and PTX treatments have favourable effects on lung function by reducing protamine-induced leukocyte sequestration into lungs at the end of CPB.

The histological effect of harmonic scalpel and electrocautery in lung resections. An experimental study in a rat model.

AIM: In the last decade, ultrasonically activated scalpels (the Harmonic Scalpel, HS) have been developed and used for both open and endoscopic surgical procedures. The present study compares the deepness of lung tissue damage caused by HS and unipolar electrocautery (EC) in rats. METHODS: Ten rats were used for the study. Morphological damage on lung parenchyma of the rats was measured with the ocular micrometer in light microscopy. RESULTS: The mean depth of the tissue damage was 0.23+/-0.08 mm in the HS group, and 0.33+/-0.10 mm in the EC group. The difference was statistically significant between the 2 groups (p=0.028). CONCLUSION: HS induces significantly less tissue damage than EC in rat lungs.

The effects of intracoronary administration of vitamin E on myocardial ischemia-reperfusion injury during coronary artery surgery.

BACKGROUND: Vitamin E has a strong antioxidant capacity, and has been used in several ischemia-reperfusion studies. The aim of this study was to investigate the effects of water-soluble vitamin E (alpha-tocopherol) on myocardial protection during coronary artery surgery. METHODS: Water soluble vitamin E (100 mg) in tepid saline (n = 14) or tepid saline alone (n = 16) was administered into the coronary arteries at the end of aortic cross-clamping. Cardiac troponin-I (cTn-I), MB-isoenzyme of creatine kinase (CK-MB), myoglobin, blood gas, and lactate levels in systemic and coronary sinus blood and hemodynamic variables were assessed during and after the operation. RESULTS: Eight hours after reperfusion, cTn-I levels increased to 3.06 +/- 1.8 ng/ml and 6.97 +/- 3.9 ng/ml in the vitamin E group and control group, respectively (p = 0.01). Coronary sinus lactate concentration was 2.68 +/- 0.5 mmol/l in the vitamin E group and 4.01 +/- 1.5 mmol/l in the control group 60 minutes after reperfusion (p = 0.027). CONCLUSIONS: Administration of vitamin E into the coronary arteries before removal of the aortic cross-clamp can reduce myocardial cell injury and protect the myocardium from ischemia-reperfusion injury.

The importance of pulmonary artery circulation during cardiopulmonary bypass.

This study sought to determine changes in transpulmonary difference in blood cells and alveolar-arterial oxygen (A-aO2) gradient when pulmonary artery circulation was obstructed in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Eighteen patients were divided into group A (control group; X-clamp placed on aorta, n = 9) and group B (pulmonary ischaemia group; X-clamp placed on aorta and pulmonary artery, n = 9). Haematological parameters were compared before CPB and up to 90 min after declamping. A-aO2 gradient differences were compared before and 2 h and 6 h after declamping. A transpulmonary increase in leucocyte levels normalized after 60 min in group A but remained higher in group B. A transpulmonary increase in neutrophils normalized after 60 min in group A and 90 min in group B. Increased lymphocyte levels normalized after 30 min in group A and 90 min in group B. A-aO2 gradient was determined as: group A (294.8 +/- 74.3) and group B (321.2 +/- 73.3) before X-clamping; group A (132.7 +/- 22.7) and group B (236.6 +/- 41.5) 2 h after declamping; and group A (72.2 +/- 22.7) and group B (189.4 +/- 88.9) 6 h after declamping. When pulmonary artery circulation was obstructed during the X-clamping period, leucocyte, neutrophil and lymphocyte sequestration within both lungs increased, and an increased A-aO2 gradient was observed because of tissue damage. To prevent post-operative complications, precautions to maintain normal pulmonary artery circulation are recommended.

The effects of cardiopulmonary bypass on androgen hormones in coronary artery bypass surgery.

The effects of testosterone on coronary vasomotor regulation have been described by several recent reports. Here we investigated changes in serum androgen levels during and after cardiopulmonary bypass (CPB) in patients who had undergone coronary artery bypass surgery. Serum luteinizing hormone, free testosterone and dihydroepiandrestenedione sulphate (DHEA sulphate) levels were evaluated in 38 male coronary artery bypass surgery patients using a chemical immunoassay technique. All hormone levels were corrected to account for haemodilution. Serum-free testosterone level decreased significantly during weaning from CPB (from 15.7 +/- 4.2 nmol/l to 6.2 +/- 2.8 nmol/l), and an even greater decrease was observed in the first post-operative day (5.4 +/- 3.1 nmol/l). On the seventh post-operative day, free testosterone levels reached a normal value (11.8 +/- 5.5 nmol/l), although they were still significantly lower compared with the pre-operative value. There were slight alterations in serum DHEA sulphate levels, although the only significant decrease occurred from the first to the seventh day post-operation (from 4.7 +/- 2.2 mumol/l to 3.7 +/- 1.8 mumol/l, respectively). Serum luteinizing hormone levels were decreased during weaning from CPB (from 4.8 +/- 2.1 mIU/ml to 3.9 +/- 1.8 mIU/ml), but increased rapidly to the pre-operative value (5.5 +/- 2.5 mIU/ml) at the first post-operative day. These results show that CPB affects serum luteinizing hormone, free testosterone and dihydroepiandrestenedione sulphate levels. The free testosterone level decreases significantly both during and after CPB surgery.

The effects of modified hemofiltration on inflammatory mediators and cardiac performance in coronary artery bypass grafting.

Cardiopulmonary bypass increases the blood levels of various immune mediators, thereby leading to a systemic inflammatory response syndrome, e.g. sepsis, with some hemodynamic alterations, such as vasodilatation, tachycardia, and a decrease in systemic vascular resistance. Perioperative hemofiltration is one of the treatment modalities proposed to prevent this syndrome. Modified hemofiltration has been introduced recently by investigators who recommend that the former standard techniques are ineffective in eliminating the inflammatory mediators. The purpose of this study was to determine the effects of the modified technique on these mediators and on hemodynamic parameters. Forty patients undergoing coronary artery bypass grafting were randomized into equal control and hemofiltered groups. The hemodynamic parameters, as well as blood samples, were taken before and after hemofiltration to assess blood concentrations of interleukin-6, interleukin-8 and neopterin. The hemodynamic parameters and immune mediator levels did not differ between the two groups during the course of the study, except in the immediate postoperative periods, where cardiac output, cardiac index, and systemic vascular resistance values were significantly greater in the hemofiltered group while there were no differences in the immune mediators. The results of our study suggest that the effects of modified hemofiltration on immune mediators are still debatable. The improvement found in cardiac performance could be attributed to the prevention of hemodilution and hypervolemia.