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Biomedical subjects

Takashi Kunihara

Publications and source records attributed to Takashi Kunihara.

At least 19 recordsLinked to original sources
PubMed2006

Heparin reduction with the use of cardiotomy suction is associated with hyperfibrinolysis during distal aortic perfusion with a heparin-coated semi-closed cardiopulmonary bypass system.

We sought to elucidate the effects of different anticoagulation levels and the use of cardiotomy suction on the postoperative coagulatory and fibrinolytic systems in patients undergoing distal aortic perfusion using a fully heparin-coated (semi-)closed cardiopulmonary bypass (CPB) system incorporating a soft reservoir bag. Thirty-two patients were divided into two groups: those who underwent cardiotomy suction (S group, 18 patients) and those who did not (N group, 14 patients). We administered 1-2 mg/kg heparin in the S group, which achieved an activated clotting time (ACT) of 345 +/- 71 s. In the N group, we administered 0.7-1 mg/kg heparin, which achieved an ACT of 297 +/- 52 s. Data on platelet counts and serum levels of fibrinogen, antithrombin III, D-dimer, and fibrin degradation products (FDP) were collected, and factors influencing these variables were analyzed by multiple regression analysis. Both the patient group and the initial ACT level were independent factors influencing postoperative levels of FDP and D-dimer, whereas peak ACT level and the use of selective visceral/renal shunt/perfusion, but not the patient group, were independent factors influencing the postoperative platelet counts. In the S group, a significant inverse correlation was found between the ACT and levels of FDP or D-dimer, whereas no correlation was found in the N group. The use of cardiotomy suction was associated with elevated FDP and D-dimer levels even when a fully heparin-coated semi-closed CPB system was used. Lower ACT levels with the use of cardiotomy suction were associated with higher FDP and D-dimer levels, whereas such a relationship did not exist when cardiotomy suction was not used.

Aged↗
PubMed2006

Spontaneous perigraft hematoma suggesting transgraft hemorrhage seven years after thoracic aortic replacement with a Dacron graft.

As a previously unrecognized late graft-related complication, we report a case of spontaneous perigraft hemorrhage, which was evidenced by contrast extravasation on computed tomographic scan seven years after thoracic aortic replacement with a knitted Dacron graft. There was no anastomotic problem or graft tear, and the hematoma seemed to result from transgraft hemorrhage. Inadequate graft healing and use of a knitted graft in the thoracic aorta seem underlying. Surgeons should be aware of this complication and we advocate careful long-term follow-up.

Aged↗
PubMed2006

Percutaneous mesenteric stenting followed by laparoscopic exploration for visceral malperfusion in acute type B aortic dissection.

A 55-year-old man underwent percutaneous mesenteric and left renal stenting for malperfusion in acute type B aortic dissection. Laparoscopic exploration was performed immediately after percutaneous revascularization to ensure the integrity of the abdominal viscera. Because the diagnosis of mesenteric infarction may sometimes be difficult and its delay can be fatal, we advocate laparoscopic exploration as a mini-invasive method after percutaneous management of visceral malperfusion, if the integrity of the abdominal viscera needs to be verified.

Aortic Dissection↗
PubMed2006

Arterio-jugular differences in serum S-100beta proteins in patients receiving selective cerebral perfusion.

PURPOSE: The early increase in serum S100beta after cardiopulmonary bypass (CPB) seems to be derived from an extracerebral source. To exclude contamination, we investigated the arterio-jugular differences in S100beta levels in patients receiving selective cerebral perfusion (SCP). We also evaluated the brain-protective effect of SCP by comparing the arterial S100beta levels with those in patients undergoing coronary artery bypass grafting (CABG). METHODS: We measured arterial and jugular venous levels of S100beta in ten patients undergoing aortic arch repair with SCP for up to 12 h postoperatively (SCP group). We also measured arterial levels of S100beta in nine patients undergoing CABG (CPB group). RESULTS: There was no incidence of hospital death or stroke. The arterial levels of S100beta in both groups were comparable and peaked just after the conclusion of CPB. The arterial and jugular venous levels of S100beta were almost equivalent. The arterio-jugular differences in S100beta levels were negligible, even in our SCP-group patient with postoperative delirium, who had a peak value three times higher than the other patients. CONCLUSIONS: The arterio-jugular differences in S100beta did not clarify the origin of their increase. Thus, measuring the jugular venous levels of S100beta in patients without postoperative clinical neurological deterioration would be of little benefit. However, SCP seems to protect the brain against S100beta release as effectively as conventional CPB.

Aged↗
PubMed2006

Proximal aortic replacement with ascending-descending bypass for a diffuse aneurysm: report of a case.

We performed successful ascending-arch aortic replacement and concomitant ascending-to-descending aorta bypass with exclusion of a descending thoracic aneurysm, via median sternotomy, for a ruptured aortic aneurysm involving the entire thoracic aorta. The patient was an 80-year-old man with cardiopulmonary dysfunction and a history of lung tuberculosis. This operation, which has been used for complex descending thoracic aortic lesions such as recoarctation, is a feasible option for a diffuse thoracic aortic aneurysm when single-stage repair is mandatory.

Aged, 80 and over↗
PubMed2006

Root replacement using stentless valves in the small aortic root: a propensity score analysis.

BACKGROUND: Root replacement using a stentless bioprosthesis may be the optimal approach to avoid patient-prosthesis mismatch in patients with a small aortic root. Primary root replacement, however, is considered to be associated with increased surgical risk. We compared early outcome of full root replacement with a stentless bioprosthesis with that of aortic valve replacement with a stented bioprosthesis using propensity score-matching analysis. METHODS: Of 231 patients undergoing elective, first-time aortic valve replacement with a small root (< or = 22 mm), 120 patients were selected using propensity score-matching analysis. They underwent either root replacement using a 23-mm stentless bioprosthesis (stentless group, n = 60) or supra-annular aortic valve replacement using a 21-mm stented bioprosthesis (stented group, n = 60). Preoperative characteristics and frequency of concomitant operations were identical. RESULTS: Duration of operation (196 +/- 54 versus 174 +/- 49 minutes), cardiopulmonary bypass (112 +/- 36 versus 91 +/- 33 minutes), and aortic cross-clamping (76 +/- 21 versus 61 +/- 21 minutes) were significantly longer in the stentless group. However, the need for perioperative transfusion and the incidence of postoperative reexploration for bleeding (3% versus 8%) was lower, and ventilation time was shorter. Mean duration of intensive care and hospital stay were also significantly shorter (2.3 +/- 1.7 versus 4.0 +/- 3.9 days, 8.9 +/- 3.1 versus 12.4 +/- 5.7 days). In-hospital mortality was identical (5% each). No independent predictor for in-hospital mortality was identified. CONCLUSIONS: Full root replacement using a stentless bioprosthesis does not increase postoperative morbidity or mortality of aortic valve replacement and may be advantageous in patients with a small aortic root.

Aged↗
PubMed2006

Extensive deployment of the stented elephant trunk is associated with an increased risk of spinal cord injury.

OBJECTIVE: Thoracic aortic aneurysm repair with the stented elephant trunk technique seems to be associated with an increased risk of spinal cord injury. We investigated whether severe atherosclerosis of the distal landing zone or extensive deployment of the stented elephant trunk is associated with increased risk of spinal cord injury. METHODS: Twenty-five patients underwent thoracic aortic aneurysm repair with the stented elephant trunk technique. The study population included 19 men and had a mean age of 73 +/- 7 years. All patients underwent a median sternotomy with cardiopulmonary bypass and selective cerebral perfusion. The elephant trunk was fixed with a Z-stent distal to the aneurysm during hypothermic circulatory arrest. Thirteen patients underwent concomitant total aortic arch replacement. RESULTS: Six (24%) patients had spinal cord injury. The presence of severe atherosclerosis at the distal landing zone demonstrated a tendency to increase the incidence of spinal cord injury (36% vs 9%, P = .1218). More distal deployment of the stented elephant trunk was significantly associated with increased risk of spinal cord injury (T8.0 +/- 0.6 vs T6.5 +/- 1.1, P = .0043). Univariate logistic regression analysis identified a history of abdominal aortic aneurysm repair (P = .0296) and the vertebral level of the distal landing zone (P = .0249) as significant independent risk factors for spinal cord injury, and only the latter was significant in multivariate analysis (P = .0396). The combination of a distal landing zone of T7 or greater and a history of abdominal aortic aneurysm repair was the strongest predictor for spinal cord injury (71% vs 6%, P = .0047). CONCLUSIONS: Spinal cord injury after stented elephant trunk deployment might be related to occlusion of the excessive intercostal arteries or thromboembolism. Patients with a history of abdominal aortic aneurysm repair who require extensive deployment of the stented elephant trunk seem to be at a higher risk for spinal cord injury.

Aged↗
PubMed2005

Reoperations after failure of stent grafting for type B aortic dissection: report of two cases.

We describe our successful management of two patients who suffered complications after stent grafting for Type B aortic dissections. One patient was found to have stent-graft migration, which we treated with repeat aortic stent grafting, and the other patient had a proximal endoleak and total occlusion of the stent graft, which we treated with open surgical repair. We discuss the measures used to assist us in deciding on the most appropriate surgery, as well as the treatment alternatives.

Aged↗
PubMed2005

Inhibition of intimal/medial hyperplasia by perindopril in canine vein grafts.

We used a canine model to assess the efficacy of an angiotensin-converting enzyme inhibitor (perindopril) at modulating intimal/medial hyperplasia in vein bypass grafts. Fourteen beagle dogs were divided into medicated and control groups and underwent bilateral grafting of external jugular veins into the common carotid artery. Samples of normal veins were obtained from the control group during vein grafting. Vein grafts were harvested 1 week and 4 weeks after surgery in both groups. Subsequently, intimal/medial thickness was measured by staining with hematoxylin and eosin; antibodies for proliferating cell nuclear antigen were employed to determine the degree of cellular proliferation; apoptotic cells were detected using the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling method. In the medicated group, the intimal/medial cross-sectional area was significantly smaller and increased 8- to 9-fold in comparison to the control group, which increased 12- to 20-fold. There was a significantly higher rate of cell proliferation in the control group, whereas the medicated group showed a significantly higher rate of apoptotic cells. These data support the efficacy of perindopril at reducing intimal/medial hyperplasia in arterialized vein grafts during a short postoperative period.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2005

Use of a soft reservoir bag in a fully heparin-coated closed-loop cardiopulmonary bypass system for distal aortic perfusion during aortic surgery.

A fully heparin-coated closed-loop cardiopulmonary bypass system has recently been introduced into clinical practice. Without a venous reservoir, however, it does not allow control of the preload to the heart. We connected a soft reservoir bag in parallel with a centrifugal pump to enable preload control and clinically evaluated this modified system for distal aortic perfusion during aortic surgery. We have used the modified system in 17 patients since November 2002. For venous drainage, we use long narrow cannulae (21 +/- 2 French). We administered 1 mg/kg heparin without cardiotomy suction and 2 mg/kg heparin with suction. We compared the clinical results with those in 13 patients who underwent distal aortic perfusion with an open cardiopulmonary bypass circuit between January 2002 and February 2004. We also analyzed factors affecting the coagulation system in these 30 patients using multiple regression analysis. With the modified system, venous drainage was adequate despite the use of smaller cannulae, and heparin reduction was not associated with thrombotic complication or elevated D-D dimer levels. Abrupt rises in proximal aortic pressure on aortic cross-clamping could be avoided by allowing blood to drain into the soft reservoir bag. Clinical results were not different from those with an open system. In the multiple regression analysis, the peak activated clotting time tended to correlate with postoperative platelet counts. This system is effective in controlling the preload to the heart and allows the safe reduction of heparin dosage. It therefore seems useful for distal aortic perfusion during aortic surgery.

Aged↗
PubMed2005

Risk of spinal cord injury after operations of recurrent aneurysms of the descending aorta.

BACKGROUND: Degenerative disease of the aorta usually involves the occlusion of several intercostal and lumbar branches by mural thrombus or atherosclerotic plaques, suggesting that the blood supply to the spinal cord is mainly provided through collateral networks. Patients with previous abdominal aortic aneurysm repair and subsequent thoracoabdominal aortic reconstruction must undergo ligation of a number of these segmental arteries, presenting a greater risk of experiencing spinal cord ischemic injury. METHODS: The records of 18 patients who had experienced abdominal aortic aneurysm graft replacement and who had undergone 19 operations for thoracoabdominal aortic repair were retrospectively evaluated. All patients were male. The mean age was 66 +/- 10 years (range, 36 to 75 years); the mean interval between the two operations was 79 +/- 69 months (range, 1 to 231 months). There were 18 (95%) cases of thoracoabdominal aortic aneurysms, and one (5%) case of acute dissection of the thoracoabdominal aorta. The origin of the Adamkiewicz artery was determined preoperatively by computed tomography. Measures to avoid spinal cord injury included monitoring of evoked spinal cord potentials and selective reconstruction of the intercostal arteries under hypothermic cardiopulmonary bypass. RESULTS: There were three (16%) cases of permanent neurologic injury that included one cerebrovascular accident, one neurogenic bladder, and one paraparesis of the right lower limb. There were no cases of paraplegia or postoperative deaths. CONCLUSIONS: Surgical reconstruction of the thoracoabdominal aorta in patients who previously underwent abdominal aortic graft replacement is not related to an increased probability of developing spinal cord ischemic injury.

Adult↗
PubMed2005

Immunophilin ligands FK506 and cyclosporine A improve neurologic and histopathologic outcome after transient spinal cord ischemia in rabbits.

BACKGROUND: We comparatively evaluated the protective effect of the immunophilin ligands cyclosporine A (INN: ciclosporin), FK506, and rapamycin on the spinal cord in a rabbit model of transient ischemia. Both cyclosporine A and FK506 inhibit calcineurin, whereas rapamycin does not. METHODS: Thirty-six male New Zealand White rabbits were divided into the following 6 groups: group C, 15 minutes of spinal cord ischemia; group FK, FK506 (1 mg/kg) administered 30 minutes before ischemia; group CsA, cyclosporine A (30 mg/kg) administered 30 minutes before ischemia; group CsA-C, chronic administration of cyclosporine A (20 mg/kg) for 9 days before ischemia; group R, rapamycin (1 mg/kg) administered 30 minutes before ischemia; and group R+FK, rapamycin (1 mg/kg) administered 20 minutes before FK506 pretreatment (1 mg/kg). Group CsA-C was added because the drug does not readily cross the blood-brain barrier. Neurologic function was evaluated by Johnson's 5-point scale at 8, 24, and 48 hours after ischemia, and histopathology was assessed 48 hours after ischemia. RESULTS: At 24 and 48 hours after ischemia, the Johnson score was better in groups FK (4.0 +/- 1.1), R+FK (3 +/- 1.1), and CsA-C (2.7 +/- 1.2) than in group C (0.8 +/- 1.2). Numbers of morphologically intact anterior horn cells were higher in groups FK (31.3 +/- 9.9), R+FK (23.2 +/- 4.5), and CsA-C (18.3 +/- 6.8) than in group C (6.3 +/- 4.3). CONCLUSIONS: FK506 and chronic administration of cyclosporine A, but not rapamycin, protect the spinal cord from transient ischemia. Although these results are compatible with inhibition of calcineurin in the mechanism of neuroprotective action of these drugs, other effects through different pathways cannot be excluded before further study.

Animals↗
PubMed2005

Hypothermic circulatory arrest is not a risk factor for neurologic morbidity in aortic surgery: a propensity score analysis.

OBJECTIVE: Hypothermic circulatory arrest has been an important tool in aortic arch surgery, even though its use has recently been discussed controversially. We sought to clarify the role of hypothermic circulatory arrest as a risk factor for mortality and neurologic morbidity in aortic surgery by using a propensity score-matching analysis. METHODS: Five hundred eleven patients (60 +/- 13 years, 349 male patients) who underwent replacement of the ascending aorta with (n = 273) or without (n = 238) arch involvement were analyzed by means of multivariate analysis. Using propensity score matching, we identified comparable patient groups: HCA(+) group and HCA(-) group (n = 110 each). For aortic arch replacement, hypothermic circulatory arrest was used with a mean duration of 14 +/- 9 minutes: 12 +/- 7 minutes or 26 +/- 8 minutes for partial or total arch replacement, respectively. RESULTS: In the entire cohort multivariate analysis identified acute dissection and duration of cardiopulmonary bypass as significant predictors for hospital death. Predictors for stroke were acute dissection, diabetes mellitus, peripheral arterial disease, and concomitant mitral valve surgery, and predictors for temporary neurologic dysfunction were peripheral arterial disease and age. After propensity score matching, the incidence of death (HCA[+]: 0.9% vs HCA[-]: 2.7%), stroke (0% vs 1.8%, respectively), and temporary neurologic dysfunction (15.5% vs 13.6%, respectively) was comparable between the 2 groups. Multivariate analysis identified age, diabetes mellitus, peripheral arterial disease, and concomitant coronary artery bypass grafting as the independent risk factors for temporary neurologic dysfunction. CONCLUSIONS: In a standard clinical setting (hypothermic circulatory arrest of <30 minutes and nasopharyngeal temperature of <20 degrees C), hypothermic circulatory arrest constitutes no significant risk for mortality or neurologic morbidity and thus appears clinically safe. Patient-related risk factors primarily determine clinical outcome.

Adolescent↗
PubMed2005

Circulating big endothelin-1: an active role in pulmonary thromboendarterectomy?

BACKGROUND: Pulmonary thromboendarterectomy is an effective treatment for patients with chronic thromboembolic pulmonary hypertension. The early postoperative course may be associated with pulmonary vasoconstriction and profound systemic vasodilation. We investigated the potential involvement of endothelins in these hemodynamic alterations. METHODS: Seventeen patients with chronic thromboembolic pulmonary hypertension (pulmonary vascular resistance, 1015 +/- 402 dyne x s x cm(-5) [mean +/- SD]) underwent pulmonary thromboendarterectomy with cardiopulmonary bypass and deep hypothermic circulatory arrest. Peripheral arterial blood samples were drawn before sternotomy, during cardiopulmonary bypass before and after deep hypothermic circulatory arrest, and 0, 8, 16, and 24 hours after surgery and were analyzed for big endothelin-1. The patients were divided into 2 groups according to whether their preoperative big endothelin-1 plasma level was above or below the cutoff point of 2.1 pg/mL, as determined by receiver operating characteristic curve analysis (group A, big endothelin-1 <2.1 pg/mL, n = 8; group B, big endothelin-1 > or =2.1 pg/mL, n = 9). RESULTS: Patients in group B, with higher preoperative big endothelin-1 levels (3.2 +/- 1.0 pg/mL vs 1.5 +/- 0.4 pg/mL; P < .001), were poorer operative candidates (preoperative mean pulmonary artery pressure, 51.3 +/- 7.1 mm Hg vs 43.6 +/- 6.2 mm Hg; P = .006) and had a poorer outcome (mean pulmonary artery pressure 24 hours after surgery, 32.6 +/- 9.5 mm Hg vs 21.8 +/- 6.2 mm Hg; P < .001). Positive correlations were found between preoperative big endothelin-1 levels and preoperative mean pulmonary artery pressure (r = 0.56; P = .02) as well as postoperative mean pulmonary artery pressure at 0 hours (r = 0.70; P = .002) and 24 hours (r = 0.63; P = .006) after surgery. Preoperative big endothelin-1 levels predicted outcome (postoperative mean pulmonary artery pressure at 24 hours after surgery) after pulmonary thromboendarterectomy (area under the receiver operating characteristic curve, 0.85). Peak big endothelin-1 levels also correlated with maximal vasopressor dosage (r = 0.65; P = .004). CONCLUSIONS: Preoperative big endothelin-1 levels seem to correlate with the hemodynamic alterations observed in pulmonary thromboendarterectomy and may be used to predict hemodynamic outcome after pulmonary thromboendarterectomy.

Endarterectomy↗
PubMed2005

[Crawford type II thoracoabdominal aortic aneurysm repair using deep hypothermic circulatory arrest and continuous proximal aortic perfusion].

We successfully operated a patient with Crawford type II dissecting thoracoabdominal aortic aneurysm using deep hypothermic circulatory arrest and continuous proximal aortic perfusion. A 70-year-old male who had a history of chronic Stanford type B aortic dissection treated by Y-graft replacement of the abdominal aorta 2 years ago underwent dissecting thoracoabdominal aotic aneurysm repair due to expansion of the aneurysm. A preoperative examination revealed 90% stenosis in his coronary system. We used deep hypothermic circulatory arrest (bladder temperature: 22 degrees C) and continuous proximal aortic perfusion as adjuncts to prevent organ malperfusion (including the coronary arteries) or embolism because sequential aortic clamping seemed impossible and the true lumen became narrowed. To minimize the duration of the extracorporeal circulation (ECC), visceral branches were reattached using a selective shunt after conclusion of ECC. The duration of aortic cross-clamping, ECC, and operation was 170, 302, and 1,020 minutes, respectively. The patient required mechanical ventilation for 12 days but survived the operation and was discharged after 42 days hospitalization without any neurologic sequela. A perioperative intensive treatment must be required to prevent morbidities related to extensive thoracoabdominal aortic aneurysm repair.

Aortic Aneurysm, Abdominal↗
PubMed2005

[Acute type A aortic dissection associated with intestinal necrosis].

We report a case with acute type A aortic dissection associated with occlusion of the celiac artery (CA) and the superior mesenteric artery (SMA) who underwent replacement of the aortic valve and the ascending aorta concomitant with CA and SMA bypass grafting and partial resection of the ileum and the cecum. A 79-year-old man who has a history of Y-graft replacement of abdominal aortic aneurysm developed re-dissection of thrombosed type A acute dissection 2 weeks after the onset. We performed CA and SMA bypass grafting followed by replacement of the aortic valve and the ascending aorta. In spite of successful revascularization of the CA and SMA, residual necrosis in the ileum and the cecum necessitated resection of them. He was discharged 11 months postoperatively without neurological sequelae.

Aged↗
PubMed2005

Evolving strategy and results of spinal cord protection in type I and II thoracoabdominal aortic aneurysm repair.

PURPOSE: We report our strategy and results of spinal cord protection in Crawford I and II thoracoabdominal aortic replacement. : METHODS: Retrospective analysis of 43 elective operations. Before 1994, we reconstructed segmental arteries during a single period of blood flow interruption in 11 of 12 patients, using distal aortic perfusion and evoked spinal cord potential (ESCP) monitoring. Deep hypothermia was used in one. Since 1994, we used multi-segmental sequential repair, in which T8-L1 arteries were sequentially reconstructed irrespective of evoked potential change, in 20 of 31 patients. In the remaining 11, deep hypothermia was used. Cerebrospinal fluid drainage (CSFD) was introduced in 1996 (n=26), and continuous infusion of naloxone in 1999 (n=17). RESULTS: In patients undergoing distal aortic perfusion without multi-segmental sequential repair, six spinal cord injuries including two deaths occurred. Change in evoked potentials was observed in nine of 10 monitored patients. With multi-segmental sequential repair, only one spinal cord injury occurred, and three of 11 monitored patients showed evoked potential change. With deep hypothermia, no spinal cord injury occurred. Multivariate analysis identified operation without multi-segmental sequential repair as a risk factor for spinal cord injury (p=0.008). CONCLUSION: Evolving strategy resulted in an improved outcome. Both multi-segmental sequential repair and deep hypothermia were more effective than our previous technique.

Adult↗