Tadanori Kawada

Analysis of the anatomic changes in the thoracic cage after a lung resection using magnetic resonance imaging.

The thoracic cage after a lung resection is filled by the remaining lobes, the elevated diaphragm, the diminished thoracic cage, and by mediastinal shifting. The changes in the thorax after a lung resection were quantified using magnetic resonance imaging. The study group consisted of 39 patients who had undergone a lobectomy, four who had undergone a pneumonectomy, and 14 controls. The left ventricular angle, ascending aortic angle, mediastinal shift, longitudinal length of the thoracic cage, the distance between the thoracic apex and the level of the aortic valve, and diaphragmatic elevation were all measured. After a right lower lobectomy, the mediastinum shifted more rightward than after a right upper lobectomy. The diaphragm became more greatly elevated after a right upper lobectomy than after a right lower lobectomy. When a chest wall resection was added to a right upper lobectomy, the mediastinal anatomical changes decreased. After a left upper lobectomy, the degree of mediastinal shifting was greater than after a left lower lobectomy. A left upper lobectomy shifted the mediastinum at the level of the right atrium. This method is easily reproducible and was found to be effective for quantifying the changes in the thorax after a lung resection.

Simultaneous monitoring of somatosensory evoked potentials and regional cerebral oxygen saturation combined with serial measurement of plasma levels of cerebral specific proteins for the early diagnosis of postoperative brain damage in cardiovascular surgery.

Combined somatosensory evoked potential (SEP) and regional brain oxygen saturation (rSO2) monitoring and simultaneous measurement of plasma levels of S100Β and creatine kinase-isozyme BB (CK-BB) were performed to evaluate how reliable these diagnostic modality complexes are in the early prediction of neurological complications after surgery. Between 1999 and 2002, intraoperative SEP and rSO2 monitoring combined with measurements of S100Β and CK-BB levels in blood were performed in 82 consecutive patients undergoing cardiovascular operations with cardiopulmonary bypass (CPB). Twelve (14.6%) of these patients were diagnosed as having neurological complications after surgery; seven with transient neurological dysfunction (8.5%), and five with permanent stroke (6.1%). Twenty one of 82 patients in whom rSO2 was recorded were judged abnormal; however, only nine of the 21 (42.9%) were diagnosed as having brain damage – diagnostic sensitivity and specificity being 75.0% and 82.9%, respectively. All six patients who showed abnormal SEP during surgery had neurological complications, but normal SEP was recorded in six other patients with apparent evidence of neurological complications – diagnostic sensitivity and specificity being 50% and 100%, respectively. There were no significant differences in S100Β levels between patients with and without brain complications at 1 h and 24 h after CPB, but significant differences were detected in CK-BB levels at 24 h after CPB. In conclusion, simultaneous abnormalities detected in SEP and rSO2 are highly predictive of cerebral neurocirculatory disturbances, but they are not so sensitive in diagnosing restricted focal cerebral lesions. Additional determinations of blood CK-BB levels might be valuable only to confirm the newly established brain complications.

Changing predictors of postoperative mortality in acute type A aortic dissection. Is only coronary artery compromise significant

OBJECTIVES Rapid emergency transport and early diagnosis and surgical treatment for acute type A aortic dissection have improved postoperative survival, which has, however, plateaued at about 80%. End-organ malperfusion is regarded as a strong predictor of postoperative mortality, replacing factors such as cardiac tamponade complications, aortic rupture, and left ventricular dysfunction due to aortic insufficiency. It is thus important to reevaluate risk factors for surgical death to assess current therapeutic strategies. METHODS We statistically analyzed potential risk factors for perioperative death in 88 patients undergoing surgical repair for type A aortic dissection between January 1990 and December 1999. RESULTS Univariate analysis showed that cardiopulmonary arrest (adjusted odds ratio: 13.78; p < 0.01) and malperfusion of more than 1 vital organ (adjusted odds ratio 4.97, p < 0.01), especially myocardial ischemia due to coronary artery dissection (adjusted odds ratio 3.21, p < 0.05), significantly increased the likelihood of operative death. Multivariate logistic regression analysis showed only cardiopulmonary arrest (p < 0.01) and concomitant coronary artery bypass grafting necessitated in cases complicated by evolving myocardial infarction (p < 0.05) to be independent predictors of postoperative mortality. CONCLUSION Preoperative complication from coronary dissection was the most important predictor of early postoperative mortality in this series. In such cases, rapid surgical intervention before myocardial infarction develops is vital to saving lives.

Argatroban, an attractive anticoagulant, for left heart bypass with centrifugal pump for repair of traumatic aortic rupture

Systemic heparinization often increases the risk of fatal bleeding from other injured organs in surgical repair of the aorta using extracorporeal circulation in patients with traumatic aortic rupture associated with multisystem injuries. We used an antithrombin agent, argatroban, as an alternative anticoagulant in left heart bypass with the Bio-Medicus centrifugal pump in 7 of 9 recent patients who underwent aortic repair using left heart bypass. All these patients survived without obvious evidence of systemic thromboembolization. Surgical treatments for other organ injuries were carried out in 3 patients concomitantly or immediately after aortic repairs without undue blood loss. Argatroban may have a complementary effect for preventing thrombus formation without aggravating bleeding tendency because of its monotarget specificity to thrombin. We believe intravenous administration (0.5 to 2 micrograms/kg/min) of argatroban is a safe anticoagulant for left heart bypass in repairs of traumatic aortic rupture associated with multiple organ injuries.

Stent graft treatment for thoracic and thoracoabdominal aortic disease using a unibody Z-stent that adapts to flexure.

Positioning a stent graft (SG) that adapts to the anatomical shape of the aorta is important to prevent complications after SG procedures to treat aortic disease. The Gianturco Z-stent has several benefits, but its rigid structure prevents adaptation to flexure. We improved this stent and studied its ability to adapt in the clinical environment. We positioned SGs and inspected their adaptability to flexure in an aortic arch model. We examined several gap lengths and strut directions, and determined the distance generated between the stent and the aortic wall. We found that adaptation was quite satisfactory with a gap of more than 10 mm or when the struts faced the major flexure or the side of the model aorta. Based on these findings and to facilitate placement, we manufactured the unibody Z-stent with 10-mm gaps. The unibody Z-stent was applied to treat thoracic and thoracoabdominal aortic disease in seven patients. The SG was positioned from the femoral or iliac artery in five patients and from an anastomosed graft to the ascending aorta after median sternotomy and bypass of the arch branches in two patients. A minor endoleak developed in one patient. None of the other six patients developed complications or died during the procedure, although one patient died in the hospital due to cerebral infarction. The unibody Z-stent was applied as a SG that adapts to flexure of the aorta and was easy to apply. The frequency of complications was apparently decreased after clinical application of the unibody Z-stent in SG treatment for thoracic and thoracoabdominal aortic disease.

Pulmonary adenocarcinoma metastatic to the gingiva

Abstract Gingival metastasis from lung cancer is very uncommon. We report a case of distant metastasis of pulmonary adenocarcinoma in the mandibular gingiva. A 54-year-old man was admitted to our hospital on September 1, 1997 with hemoptysis. Right upper lobectomy with mediastinal lymph node dissection was performed on September 16. On the 14th postoperative day, the patient complained of a gingival swelling. In the lower right premolar area, a wide pedunculated mass was seen on the mandibular gingiva. Excisional biopsy of the tumor was performed, and histopathological examination revealed that the tumor was a metastatic lesion from the pulmonary adenocarcinoma. The patient received 46.8 Gy of linac irradiation to the tumor area and the entire oral condition improved markedly. However, bilateral adrenal gland metastases were recognized, and left inguinal lymph node metastasis was detected 2 months after lung resection. He developed tumor metastases to multiple organs and died of respiratory failure on December 12, 1997.

Extra-Anatomical Bypass Grafting for Coarctation of the Aorta associated With Annuloaortic Ectasia Long-Term Outcome

Two patients each with a rare combination of aortic coarctation and annuloaortic ectasia underwent successful single-stage repair in which the aortic root was reconstructed with a valved conduit, and an extra-anatomical bypass was made by grafting from the ascending to the abdominal aorta. Although the long-term outcome of such a long extra-anatomical bypass graft has not yet been established, the use of the graft for reducing the risk to coarctation-related complications during the early and late postoperative periods appears promising.

Clinical trial of argatroban, a direct thrombin inhibitor, as an anticoagulant in cardiopulmonary support and apheresis in emergency patients: a preliminary report

Abstract To evaluate the safe and effective use of argatroban, a competitive direct thrombin inhibitor, as an alternative anticoagulant for percutaneous cardiopulmonary support (PCPS) and continuous hemofiltration or hemodiafiltration (CHF/CHDF), a preliminary multicenter clinical trial was conducted between October 1999 and September 2000. Nine patients who underwent PCPS and/or CHF/CHDF were enrolled in the study during this period. The dosage of argatroban was controlled so that the activated clotting time (ACT) was maintained at around 180 to 200 s. The mean duration of argatroban administration was 82 ± 92 h, and the mean dose was 0.67 ± 0.40 μg kg+1 min−1. Severe hemorrhagic complications requiring the discontinuation of argatroban administration were not observed in any of the patients. Platelet loss was prevented to some degree, and plasma levels of fibrinogen were well preserved during PCPS/CHDF. Except for two patients undergoing CHDF, clot formation within the extracorporeal circulation circuit was not identified macroscopically after the discontinuation of the procedures. We conclude that argatroban might be useful as an alternative anticoagulant in cases where heparin cannot be safely used because of the increased risk of bleeding complications, thrombocytopenia, and/or hypofibrinogenemia. Although the optimal dose of argatroban has not been established, we propose an initial starting dose of 0.7 to 1.0 μg kg−1 min−1, followed by adjustments to maintain an ACT of between 180 and 250 s.

Use of argatroban as an alternative anticoagulant in cardiopulmonary support with an oxygenator: experimental study

Abstract Argatroban, a selective and competitive antithrombin agent synthesized in Japan, was assessed for use as an alternative anticoagulant for partial venoarterial bypass with an oxygenator, by determining serial changes in hemostatic molecular markers. Fourteen dogs were divided into 3 groups in which partial veno-arterial bypass was carried out: a group in which no anticoagulant was used (group N, n = 3), a group in which 200 IU/kg of bolus heparin was used (group H, n = 5), and a group in which 10 μg/kg per min of intravenous argatroban was used (group A, n = 6). Both thrombin-antithrombin complex and fibrinopeptide A increased significantly in group N; they did not increase in group H. Group A showed high thrombin-antithrombin complex levels and significantly high fibrinopeptide A levels throughout the bypass procedure in comparison to levels in group H. However, plasma fibrinogen was maintained at higher levels in group A than in group H. Platelet count decreased significantly immediately after the start of bypass in groups N and H, but no significant change in platelet count was observed in group A. In conclusion, argatroban at a dose that prolongs activated clotting time to 200 s suppressed thrombin and fibrin generation less effectively than did full-dose heparin. However, excessive consumption of fibrinogen and accelerated fibrinolysis were not observed, and more platelets were preserved, suggesting that argatroban can be used safely in partial cardiopulmonary bypass with an oxygenator.

Use of prothrombin fragment 1+2 for evaluating anticoagulant therapy after mechanical heart valve replacement

Prothrombin fragment 1+2 (F1+2) is a coagulation factor newly used as a molecular marker to monitor anticoagulant therapy in patients undergoing heart valve replacement. We evaluated the usefulness of F1+2 against that of prothrombin time (PT) reported as the internationalized normalized ratio (INR) in 93 patients undergoing mechanical heart valve implantation between August 1999 and July 2000. The study group consisted of 38 men and 55 women, with an average age of 61.1±11.2 years. The surgeries were 34 aortic replacements, 9 double valve replacements, and 50 mitral valve replacements. Warfarin doses were controlled based on PT-INR values at a target range of 1.5–2.5 F1+2 levels in the 0.4–1.2 nmol/l level were considered normal. No thromboembolism or bleeding complication occurred in any patient during the mean follow-up period of 12 months. The overall correction coefficient between F1+2 and PT-INR was 0.165 (P<0.001). A few specimens showed abnormally high levels of F1+2, even when PT-INR values were within the optimal range. The plasma levels of F1+2 that fell within normal range came from specimens with PT-INR values <1.50. The plasma levels of F1+2 that corresponded to PT-INR values of 1.50–2.50 fell just within the normal range, and the F1+2 levels corresponding to PT-INR values >2.50 were less than half of the lower limit of normal. Our analysis involving F1+2 confirmed PT-INR in the 1.5–2.5 range following mechanical heart valve implantation to be optimal. We found that using F1+2 to monitor individual response to anticoagulation therapy is useful when PT-INR values are difficult to obtain.