ABSTRACT
In Japan, doctors inexperienced stent-graft new devices are required to secure agreement on criteria and choice of the device size in endovascular aneurysm repair (EVAR) from experienced doctors. It was hoped that strict patient selection might reduce the learning curve for initial successes in given procedures. In a leading center in Japan, a number of cases which were scheduled for operation at other institutes were evaluated anatomically. We surveyed the initial success of Zenith AAA system implantation in the remaining cases by inexperienced doctors and evaluated the results. This study aimed to verify the validity of strict patient selection in improving the success rate of inexperienced doctors. We enrolled 112 consecutive patients from 19 institutes, who were scheduled for repair between January and October in 2007. All patients were evaluated on the basis of a less-than-3mm reconstructed CT image. Mean patient age was 76±5.7 years. All cases satisfied the Zenith's anatomic prerequisites. Fifteen cases were excluded for various reasons, the major reason being insufficiency of the proximal landing zone (LZ) length, angle and contour. The second reason was difficulty to approach via the iliac artery. Ninety seven cases were included, of which 17 cases were low-risk candidates for EVAR. Medium-risk seventy two cases requiring some advice to avoid problems with device size, technique of implantation and choice of main-body side. Eight cases were high-risk, requiring the presence of an experienced surgeon. Excluded cases had significantly shorter proximal LZ, larger aortic diameters 15mm below the renal artery and tortuous access routes on preliminary measurement by inexperienced doctor. Perioperative mortality was 0%, while the major complications were injury to the iliac artery in one high-risk case and thromboembolism of the superficial femoral artery in another. Perioperative proximal type I endoleak occurred in 5 cases. In 3 of these cases, the endoleak was eliminated by implantation of a Palmatz stent. In the other 2 cases, it disappeared within a month without additional procedures. These cases had a significantly greater angle between the proximal LZ and the suprarenal aorta and significant amount of mural thromboses in the proximal LZ. Perioperative type III endoleak occurred in 3 cases. In all cases the endoleak was eliminated by additional procedure. Perioperative type II endoleak occurred 8 cases. In 3 of these cases, the endoleak disappeared within a month. In the 5 other cases, the endoleak did not disappear. Mid-term results showed iliac leg thromboembolism in one case and new type II endoleaks in 3 cases. Type II endoleak occurred in cases which had significantly greater angles between the proximal LZ and the aneurysm. The results which were evaluated in our center had excellent perioperative and mid-term outcomes. We think this evaluation system is effective for risk assessment and reduces the learning curve in EVAR. In anatomically marginal cases, it is possible for proximal type I endoleak and injury of the iliac artery to occur. It is impossible to exclude these marginal cases if treatment need for EVAR is a priority. In these cases, lessexperienced operators should be trained in troubleshooting techniques in advance.
ABSTRACT
Prosthetic and bioprosthetic materials currently in use lack growth potential and therefore must be repeatedly replaced in pediatric patients as they grow. Tissue engineering is a new discipline that offers the potential for creating replacement structures from autologous cells and biodegradable polymer scaffolds. In May 2000, we initiated clinical application of tissue-engineered vascular grafts seeded with cultured cells. However, cell culturing is time-consuming, and xenoserum must be used. To overcome these disadvantages, we began to use bone marrow cells, readily available on the day of surgery, as a cell source. Since September 2001, tissue-engineered grafts seeded with autologous bone marrow cells have been implanted in 44 patients. The patients or their parents were fully informed and had given consent to the procedure. A 3 to 10ml/kg specimen of bone marrow was aspirated with the patient under general anesthesia before the skin incision. The polymer tube serving as a scaffold for the cells was composed of a copolymer of lactide and ε-caprolactone (50: 50) which degrades by hydrolysis. Polyglycolic or poly-l-lactic acid woven fabric was used for reinforcement. Twenty-six tissue-engineered conduits and 19 tissue-engineered patches were used for the repair of congenital heart defects. The patients' ages ranged from 1 to 24 years (median 7.4 years). All patients underwent a catheterization study, CT scan, or both, for evaluation after the operation. There were 4 late deaths due to heart failure with or without multiple organ failure or brain bleeding in this series; these were unrelated to the tissue-engineered graft function. One patient required percutaneous balloon angioplasty for tubular graft-stenosis and 4 patients for the stenosis of the patch-shaped tissue engineered material. Two patients required re-do operation; one for recurrent pulmonary stenosis and another for a resulting R-L shunt after the lateral tunnel method. Kaplan-Meier analysis in relation to patients' survival was 95% within 3 years. There was only 1 patient (who underwent a total cavo-pulmonary connection procedure) requiring re-intervention in the tubular graft group and the material-related event-free rate was 96% within 3 years. This tissueengineering approach may provide an important alternative to the use of prosthetic materials in the field of pediatric cardiovascular surgery. As it is living tissue, these vascular structures may have the potential for growth, repair, and remodeling. However, this approach is still in its infancy, further studies to resolve the problems presented, and longer follow-up in patients are necessary to confirm the durability of this approach.
ABSTRACT
We describe a case of postoperative aortic valve regurgitation (AR) after arterial awitch operation (ASO) successfully managed by the modified Konno procedure. A 4-year-old girl with complete transposition of the great arteries (TGA, Type II) had undergone the ASO (LeCompte maneuver) at 10 days of age. Because of progression of moderate AR 4 years after ASO, the modified Konno procedure with aortic valve replacement (SJM 21mm) was successfully performed. She remains in good clinical condition at the last follow-up at 5 years.
ABSTRACT
The use of the internal mammary artery (IMA) is now routine in most coronary artery bypass grafting (CABG) because of its improved long-term patency and survival. A small but important percentage of these patients will require valve surgery and thoracic aortic aneurysm repair following CABG. These operations present a challenging problem for the cardiac surgeon because of difficulties regarding approach, dissection around the IMA and optimal myocardial protection. We investigated surgical results and the effectiveness of various methods of myocardial protection in 8 patients who underwent reoperations between December 1983 and June 2005. The mortality was 13%. There were 2 perioperative myocardial infarctions (25%), 6 cases of prolonged ventilation (75%), 3 cases of low output syndrome (38%), 1 case of acute renal failure (13%) and 1 case of sepsis (13%). We carried out resternotomy for 6 patients without any hospital death or perioperative myocardial infarction. Our reoperation approach had acceptable risk control with resternotomy, avoidance of dissecting the IMA and hypothermic perfusion.
ABSTRACT
We performed the Senning operation and pulmonary valvotomy in an 11-month-old baby with transposition of the great arteries (TGA) with an intact ventricular septum (IVS), and bicuspid pulmonary valvular stenosis associated with pulmonary hypertension (PH). Preoperative catheterization showed a pressure gradient (PG) between the left ventricle (LV) and main pulmonary artery (MPA) of 35mmHg, mean pulmonary artery pressure (MPAP) of 56mmHg, and pulmonary vascular resistance (PVR) of 11.2unit·m<sup>2</sup>. The pure oxygen inhalation test showed a decrease in MPAP from 56 to 38mmHg, and a decrease in PVR from 11.2 to 5.5 unit·m<sup>2</sup>. We could not perform lung biopsy to determine the surgical indications in terms of PH due to preoperative progressive congestive heart failure in this patient. Postoperative catheterization (28 days after the Senning operation) showed a decrease in PG between the LV and MPA to 8mmHg, and MPAP also decreased to 17mmHg. Two radical operations were possible in this patient. One was the arterial switch operation (ASO), and the other was the atrial switch operation, i. e. the Senning or the Mustard operation. We selected the Senning operation because there was the possibility that the new aortic valve might develop persistent stenosis and regurgitation after ASO and pulmonary valvotomy. The Senning operation may be an alternative in selected patients with TGA with IVS and pulmonary valvular stenosis.
ABSTRACT
When homo- or isograft was used as a right ventricle-pulmonary artery bypass in the Rastellitype procedure for congenital heart disease, reoperation was mandatory due to calcification and conduit stenosis after several years. However, the survival period of intimal cells or smooth muscle cells has not been clarified, nor has the question of whether the calcification is due to an immunoreaction or not. Thus, to observe the geometrical or pathological changes of the grafts, an experimental model of homograft transplantation was established using rats' aorta, where cyclosporine A (CsA) was given after the transplantation. The rats used were 8 or 9 weeks old. Male King rats were the donors, and female Lewis rats were the recipients. The descending thoracic aorta was transplanted to the infra-renal abdominal aorta. There were 2 experimental groups; one in which CsA was not given (<i>n</i>=35), and the other in which CsA was given (<i>n</i>=44). The animals were sacrificed at 1, 2, 4, 6, 8, and 12 weeks after the transplantation, and were examined by an optical microscope after slicing longitudinally. The area of the cross-section, intima and the media of the vessel were calculated by 2 ways; manually, and by computer. These data were used to calculate and analyze the percentage of intima-media area, the ratio of the intima/media area, and the percentage of intima area and media area. The effect of suppression of the percentage of intima-media area and the percentage of the intima area were revealed to be significant at an acute stage after brief high dose CsA administration. From this result, we suggest that there is a possibility of a rejective reaction participating in the intimal hyperplasia in the acute phase after homograft transplantation.
ABSTRACT
When local hemostatic agents are used in surgery, rapid dissolution followed by prompt absorption without adverse effect after successful hemostasis are essential qualities. Residual hemostatic materials greatly influence host cells during the wound healing process. Biocompatibility of material is also essential. Furthermore, hemostatic agents also should be free of cytotoxicity that may block mitosis and migration of host cells, so that wound healing can proceed smoothly. For the evaluation of biocompatibility and cytotoxicity, 4 commercially available hemostatic agents; oxidized regenerated cellulose (Surgicel<sup>®</sup>), gelatin sponge (Spongel<sup>®</sup>), microfibrillar collagen (Avitene<sup>®</sup>) and cotton type collagen (Integran<sup>®</sup>) were tested <i>in vitro</i> and <i>in vivo</i>. The hydrogen ion concentration (pH) of culture medium containing hemostatic agents was measured. Fibroblasts were cultured with the hemostatic agents in petri dishes for 5 days. A rabbit ear chamber (REC) model was used to evaluate tissue compatibility and the healing process. Each hemostatic agent was placed in the REC and evaluated macroscopically once a week up to 5 weeks. At 72h, the pH of the culture medium containing Surgicel was low at 7.2, while they stayed between 7.7-7.8 with the other agents. In the fibroblast culture containing Surgicel, cell detachment occurred and the cell numbers decreased, while no particular changes occurred with other hemostatic agents. In the REC model, after 5 weeks Surgicel was dissolved and remained in the effusion, and the healing process was disturbed by inflammation. Spongel was dissolved and absorbed, with normal vasculature. Avitene was dissolved and remained in the effusion, but did not induce strong inflammation. With Integran, the healing process was prompt but the material was still recognizable at 5 weeks. The 4 hemostatic materials tested showed differences in biocompatibility and cytotoxicity. The ability of hemostasis is important; however, after hemostasis is achieved, unused hemostatic material should be eliminated, leaving as little hemostatic agent as possible to avoid postoperative complications.
ABSTRACT
A 3-year-old girl was given a diagnosis of coronary arteriovenous fistula associated with a single right coronary artery on cardiac catheterization. The left coronary artery arose from the proximal part of the right coronary artery. The dilated left coronary artery ran in front of the right ventricular outflow tract and then divided into the left anterior descending branch and the left circumflex artery. A coronary arteriovenous fistula was in the left main coronary artery and opened into the right ventricular outflow tract. Under cardiopulmonary bypass and cardiac arrest, a transverse incision was made at the right ventricular outflow tract 1cm below the dilated vessel and the 5-mm oval-shaped orifice of the fistula was identified. This fistula was closed with a pledgetted mattress suture reinforced with over-and-over suture. Catheterization 8 months after surgery demonstrated no residual shunt and she has been doing well.
ABSTRACT
A 71-year-old man was given a diagnosis of saccular aneurysm of the aortic arch (maximum 48mm in diameter) at the age of 68. When he was 69 years old, he began to take steroids for autoimmune hepatitis (AIH). The following year, the aneurysm was enlarged to 52mm. Further examinations showed the aneurysm to extend to the ostium of the left subclavian artery. Since he had transient ischemic attacks, ultrasonography of the carotid arteries was performed. Bilateral internal carotid stenoses were detected, however, cold Xe CT showed an almost normal pattern of cerebral blood flow. We decided that operation was feasible using retrograde cerebral perfusion (RCP). Liver dysfunction due to AIH improved, and his steroid dosage was tapered. Using RCP, the no-touch technique and the elephant trunk procedure, he underwent the replacement of ascending aorta and aortic arch and was discharged without major complications. RCP and the no-touch technique might enable safer operations on patients with carotid stenoses.
ABSTRACT
After bleeding is controlled with hemostats during surgery, the residual material should be resorbed without adverse effects such as inflammation, infection or scar formation. To evaluate the biocompatibility of hemostats, three kinds of commercially available collagen hemostats, cotton type (Integran<sup>®</sup>), microfibrillar type (Avitene<sup>®</sup>), and sheet type (TachoComb<sup>®</sup>), were examined. A rabbit ear chamber (REC), a system for viewing materials <i>in vivo</i>, was applied to the auricle of male Japanese white rabbits. The REC was designed to leave a 50-μm-thick and 6.4mm-diameter chamber, and 0.5mg of each specimen (Integran; <i>n</i>=8, Avitene; <i>n</i>=6, TachoComb; <i>n</i>=6) was placed in the chamber. Macroscopic and microscopic observations were performed every week up to 5 weeks without anesthetizing or stressing the animal. In the Integran group, capillaries infiltrated between the collagen fibers, and the vasculature in the REC field was complete in 6 out of 8 animals at 5 weeks. Cotton type collagen fibers of Integran became thinner every week without effusion. In the TachoComb group, capillaries were directed toward the effusion at 2 weeks, while in the Avitene group, a similar phenomenon was not observed. The vasculature was incomplete, with either effusion or infection at 5 weeks in the Avitene and TachoComb groups. Material was recognized up to 4 weeks in the TachoComb group, whereas the space occupied by material remained vacant without vasculature in the Avitene group. Our results suggest that cotton type configuration is excellent as a collagen hemostat, with smooth capillary infiltration, rapid resorption of material and promotion of the healing process.
ABSTRACT
Fourteen patients (mean age 17.2 years, range 2 to 39 years) undergoing right ventricular outflow tract reconstruction for a Ross operation were studied between 1998 and 2000. Ten of 14 patients underwent Ross procedures and 4 received Ross-Konno procedures. Echocardiographic examination of the pulmonary homograf t was performed after surgery. The mean follow-up period was 23.1 months, ranging from 14 to 33 months. Mean peak velocity and peak gradient were 1.6±0.4m/s and 11.9±5.2mmHg, respectively. Three patients in whom echocardiography revealed a peak pulmonary gradient of 20mmHg or more were retrospectively analyzed with each catheterization data. All patients had no more than 10mmHg at the distal end of the homograft with no evidence of deformity or shrinkage. Only one patient had a trivial homograft valve regurgitation, however, no patient had more than mild pulmonary regurgitation. Patient age, donor age, and preservation period did not reveal any significant risk factor for homograft stenosis. Pulmonary homograft appears to be an excellent substitute for right ventricular outflow tract reconstruction during the mid-term postoperative period.
ABSTRACT
A 19-year-old woman with thoracic aortic aneurysm complicating coarctation of the aorta was treated successfully. Aortography and 3D-CT showed the thoracic aortic aneurysm resembling a cluster of grapes. Coarctation of the aorta was seen between the aortic aneurysm and the descending aorta, and there was a 40mmHg pressure gradient between the ascending aorta and the descending aorta. At operation, the wall of the cluster-shaped saccular aortic aneurysm was very thin. We could see the blood flow through the wall, and we thought this patient was at high risk of ruptured aneurysm. The aneurysm was excised and replaced by a Hemashield tube graft, 16mm in diameter. The left subclavian artery was also constructed using a Hemashield tube graft, 8mm in diameter. Ruptured aneurysm in a patient with aortic aneurysm complicated by coarctation of the aorta has a high risk of death, so surgical intervention should be performed as soon as possible.
ABSTRACT
With multiple-choice questions presenting one, two, or three of five choices (types A, K or X), the expected probability of a correct answer (P) can be obtained with a five-dimensional equation for the knowledge level (q), which is the probability of discriminating correct and incorrect items. From equations for each question type, we inversely estimated the q value (the estimated knowledge level), replacing P with the raw score rate in the actual examinations for promotion. The distribution and mean value of the raw score rate of type X differed from those for types A and K. However, distributions of estimated q values for the three question types were similar. This method can be used to estimate the actual knowledge level of students without the question type affecting the raw score but cannot be used to estimate incorrect knowledge.
ABSTRACT
The authors examined the frequency of thromboembolism and bleeding complications in cases of mechanical valve replacement during the past 5 years in the Tokyo area. There were 21 cases of thromboembolism and 15 cases of bleeding complications. Analyzing these cases with regard to anticoagulant therapy, 71% of the thromboembolism cases and 47% of the bleeding complication cases had 10∼25% result on the thrombotest at the time of the event. Consequently, in cases of mechanical valve replacement it is necessary to reevaluate the therapeutic range of the thrombotest results. This was a retrospective study of a TAS (The Tokyo area anticoagulation study for cardiac valve replacement by using PT-INR) trial and we intend to carry out a prospective study on the therapeutic range of the thrombotest and PT-INR.
ABSTRACT
When we surgically treat cases for dissecting aortic aneurysm with an inheritable connective tissue disorder like Marfan's syndrome, we should choose the surgical procedure carefully, paying paticular attention to whether to extend the operation, because there is every possibility that the lesion might be progressive. A 41-year-old woman with Marfan's syndrome, type A chronic aortic dissection, rapidly dilating to 80mm in diameter, and with aortic valve regurgitation was operated on with a total aortic arch replacement and the modified Bentall procedure. In the procedure, the aortic root and valve were replaced with a composite graft with a prosthetic mechanical valve, and the coronary arteries were reconstructed by direct anastmosis. In this case, the infrarenal abdominal aorta had already dilated to 40mm in diameter. In many cases with Marfan's syndrome, it was reported that the lesion was progressive and the residual dissection or new aneurysm would usually dilate and eventually rupture postoperatively. Reoperation involve a high risk. With those factors in mind, we chose total aortic replacement, including the distal aortic arch, to where the dissection would not extend. The most important thing for patients with Marfan's syndrome is the development of new or reccurrent problems. We consider that the operation designed to dissect aortic aneurysm for those patients should be performed as extensively in the surgical field as possible.
ABSTRACT
Ionescu-Shiley pericardial xenografts implanted in the mitral position between April 1980 and October 1984 were studied. In some cases the cusp was torn in a relatively early postoperative phase, thus requiring an emergency operation. Functional disorders, such as caused by the calcification of the cusp, advance at a relatively moderate pace, and the prognosis of a second operation in cases with valve dysfunction and a chronic course was favorable. The actuarial probability of freedom from reoperation was 88.5±8.7% at 5 years and 55.7±14.5% at 10 years. The structural deterioration of the pericardial valve increased about 5 years after replacement. This tendency was the same as in other bioprostheses. At 10 years the overall actuarial survival rate was 67.2±12.1%. Freedom at 10 years from thromboembolism was 84.6±9.8%. For cases whose the course is under observation at present, the strategy is to recommend an additional operation as far as possible, while continuously observing the function of the valve.
ABSTRACT
Cor triatriatum is an uncommon congenital malformation in which the fibromuscular abnormal septum divides the atrium into two compartments. Generally it is used to mean cor triatriatum sinister in which the left atrium is divided into two lumens. In typical cor triatriatum, an abnormal fibromuscular septum divides a proximal chamber that receives the pulmonary vein from a distal chamber that communicates with the left atrial appendage and the mitral valve. Several hypothesis were proposed concerning the mechanism of the abnormal septation of the atrium, but no single hypothesis could explain all the cases convincingly. We report the successful surgical treatment of a 6-month-old male patient with the rare variant of the cor triatriatum with pulmonary hypertension. The left pulmonary vein and superior right pulmonary vein drained into an accessory chamber which opened to the right atrium through a sinus venousus type atrial septum defect. The left inferior pulmonary vein drained into the true lumen which opened to right atrium through the patent foramen ovale.
ABSTRACT
We performed coronary artery bypass operation on 258 patients from July 1974 to February 1993, of whom 10 underwent a total of 11 reoperations. These 10 patients were not significantly different from the other patients with respect to gender, coronary risk factors and number of grafts used in the first operation, aside from older age and lower LVEF. The interval between the two operations was <1 year (early) or about 10 years (late) in most instances. The most common reasons for reoperation were graft failure from technical problems in early and time-related alterations in graft and progression of original disease in late cases. The outcome of reoperation was less than satisfactory, with 2 operative deaths, IABP required in 5, reoperation for bleeding needed in 3 and severe sternal wound infection of the patent vein graft postoperatively, of which atheromatous debris released from the atherosclerotic vein graft was strongly suspected to be the cause. The old vein graft should be immediately ligated at the beginning of CPB in cases with diffuse atherosclerotic vein graft in which more than several years have passed since initial operation. In reoperation, arterial graft is preferable, especially GEA graft can be used advantageously even with a left thoracotomy approach. Bypass reoperation for occlusion of LAD or Cx should be performed by a left thoracotomy approach.
ABSTRACT
Renal damage caused by hemolysis during cardiopulmonary bypass (CPB) was investigated, and the preventive effects of haptoglobin in regard to this condition was also evaluated. Nineteen patients who underwent open heart surgery were divided into two groups: a control group (<i>n</i>=11) and a haptoglobin group (<i>n</i>=8). In the control group, the level of plasma-free hemoglobin increased significantly after CPB (<i>p</i><0.01), and this level was strongly correlated with renal tubular leaking enzymes: NAG (<i>r</i>=0.76) and γ-GTP (<i>r</i>=0.81), in the Intensive Care Unit or on the first day after surgery. On the contrary, in the haptoglobin group, in which 4, 000 units of haptoglobin was added in the priming solution of CPB, no increased level of plasma free hemoglobin was observed. Furthermore, leak age of renal tubular enzymes were statistically less (<i>p</i><0.05). It was concluded that free hemoglobin was a cause of renal damage during CPB and the damage was preventable by the administration of haptoglobin.