Biomedical subjects

S Kawada

Publications and source records attributed to S Kawada.

At least 55 records · Page 3Linked to original sources

PubMed2000

Outcome of patients with cyanotic congenital heart disease undergoing a second systemic-to-pulmonary artery shunt.

BACKGROUND: Multiple systemic-to-pulmonary artery shunts often represent a deviation from the initial management strategy for cyanotic congenital heart disease. This study analysed the outcome in patients undergoing a second shunt. METHODS: Between 1965 and 1998, 80 patients required a second shunt. Patient age ranged from 11 days to 11.2 years at the initial shunt, and 4 months to 25.6 years at the second shunt. The interval between shunts ranged from 11 days to 19.6 years. RESULTS: The patient survival rates at 1, 6, 12, 60 and 120 months following the second shunt were 95.0 +/- 2.4%, 92.5+/-3.0%, 87.4+/-3.7%. 82.4+/-4.5% and 74.8+/-5.8%, respectively. Although excess pulmonary flow was not encountered after the second shunt, mode and incidence of morbidity were otherwise similar to the first one. Between 9 months and 7.5 years after the second shunt, 24 patients underwent successful definitive repair. Multivariable analysis identified pulmonary atresia (p=0.027) and a short (<1 year) interval between the two shunts (p=0.034) as the independent risk factors for long-term shunt failure. Single ventricle physiology (p=0.002) and a central approach for the second shunt (p=0.016) were independent risk factors for lack of application, or failure of intracardiac definitive repair. CONCLUSIONS: A significant limitation in longevity and quality of life is common in patients requiring a second shunt, especially those associated with pulmonary atresia, the single ventricle physiology heart, or ungraftably hypoplastic contralateral branch pulmonary artery to the first shunt. Since excess pulmonary blood flow leading to congenital heart failure and/or ventricular diastolic dysfunction is unlikely, all patients who preclude definitive repair due to decreased pulmonary blood flow even after the first shunt should be shunted again.

Blood Vessel Prosthesis Implantation↗

PubMed2000

[Effect of Down's syndrome on perioperative and long-term prognosis after ventricular septal defect repair].

In this study, we investigated perioperative and long-term prognosis and the risk of major complications after repair of ventricular septal defect in 48 patients with Down's syndrome who underwent ventricular septal defect repair between May 1980 to August 1999 were compared with those in 48 patients with normal chromosomes matched for age and time period. Pp/Ps were significantly lower after the operation in both groups; however perioperative and postoperative Pp/Ps of Down's syndrome group were significantly higher than that those of control group. The duration of intubation was significantly longer in the Down's syndrome group and the case-control study revealed that the risk of long intubation (> or = 7 days) was significantly higher in the Down's syndrome group, but the incidence of PH crisis did not differ between the 2 groups. The main reasons of prolonged intubation period were respiratory complications such as pneumonia or atelectasis. In Down's syndrome group, a 5 months old boy died of heart failure on the 5th postoperative day. All other patients were survived through a mean follow-up period of 122.4 months (the follow-up rate was 95.8%). In conclusion, the perioperative and long-term prognosis after ventricular septal defect repair in patients with Down's syndrome were similar to those in patients with normal chromosome.

Cardiac Surgical Procedures↗

PubMed2000

Placement of interatrial patch suture lines in atrioventricular canal defect repair.

BACKGROUND: The placement of the suture line for interatrial patches in complete and incomplete atrioventricular canal defect repairs varies from surgeon to surgeon despite established anatomic knowledge of the atrioventricular conduction system. This study describes our technique for it and reviews early and long-term outcomes. METHODS: Between 1980 and 1999, 64 infants and children underwent repair of either complete (n=39) or incomplete (n=25) atrioventricular canal defects. Thirty-four of the children (53.1%) had Down's syndrome. The suture line for the interatrial patch originated on either the artificial or native ventricular septal crest and continued leftward above the annulus of the left inferior leaflet of the atrioventricular valve at the posteroinferior corner. All stitches were placed in a horizontal mattress or U-shaped fashion. RESULTS: The operative survival rate was 94% (4 early deaths) and the overall survival rate was 85% (6 late deaths). Atrioventricular heart blocks occurred in none of the patients. Although left-sided atrioventricular function significantly improved with repair, two patients (3.1%) required reoperation for valve replacement because of residual or recurrent insufficiency. CONCLUSIONS: This suture technique for interatrial patches is straightforward and results in a low incidence of heart block and a low re-operation rate for left atrioventricular valve insufficiency.

Cardiac Surgical Procedures↗

PubMed2000

Hypotension after coronary arterial occlusion induces regional expression of c-Fos protein in the rat brain.

The purpose of this study was to examine comprehensively and quantitatively the effects of sustained occlusion of the circumflex branch of the left coronary artery on neuronal expression of Fos, the protein product of the proto-oncogene c-fos, in the rat brain. Occlusion coronary artery induced a fall in mean arterial pressure of about 10-30%, maintained for a period of 60 min. Baroreceptors were activated by occlusion coronary artery-induced hypotension. In control rats treated with without coronary ligation, few Fos-positive cells were observed. Following coronary artery occlusion, there was a significant increase in the number of Fos-positive cells in the several brain regions. These brain regions containing Fos-positive neurons in rats treated with coronary artery occlusion included nucleus tractus solitarius (NTS), area postrema (AP), caudal and rostral ventrolateral medulla (VLM), lateral parabrachial nucleus (PBN), supraoptic nucleus (SON), paraventricular nucleus (PVN) and central nucleus of the amygdala (CE). This finding partly differs from previous studies where Fos expression occurred by other reasons such as hypovolemia, hemorrhage, nitroprusside or hydralazine etc. These results generally fit within an emerging understanding of brain circuitry underlying cardiovascular regulation.

Animals↗

PubMed2000

Surgical treatment of a distal arch pseudoaneurysm and migrated stent-graft after interrupted aortic arch repair.

A 13-year-old girl, who had undergone a modified Blalock-Park operation using an equine pericardial patch for a type A aortic arch interruption at 10 days of age, and patch repair of a ventricular septal defect at 1 year, presented with recurrent stenosis of the aorta. She underwent balloon angioplasty which resulted in a pseudoaneurysm at the distal suture line of the patch. Endovascular stent-grafting was employed. Soon after placement, the stent-graft had migrated into the distal portion of the descending aorta. The distal aortic arch and proximal descending thoracic aorta were replaced with a prosthetic graft. The migrated stent-graft was removed. The operation was performed through an anterior approach under hypothermic circulatory arrest and selective cerebral perfusion. The postoperative course was uneventful. The migration was likely caused by the limited ability to bend the stent-graft to match the curvature of the arch, the stiffness of the scarred equine pericardial patch, and the shape of the aorta.

Adolescent↗

PubMed1999

The surgical treatment of fixed subaortic stenosis: a clinical experience in Japan.

We report herein the results of a retrospective study conducted on ten consecutive Japanese patients who underwent successful surgical relief of fixed subaortic stenosis between 1972 and 1994 at ages ranging from 8 months to 21 years, and followed for 3.6 years and 26 years. Associated cardiovascular defects were present in six patients, two had a history of infective endocarditis, a discrete fibrous ring was found in nine patients, and a redundant abnormal sheet was found in one. A stenotic structure was removed in nine patients and incised in one, while myotomy was additionally performed in one. There were no early complications or deaths. Cardiac catheterization revealed a significant decrease in the peak systolic pressure gradient from 84+/-22 mm Hg preoperatively to 32+/-22 mm Hg postoperatively (P = 0.0017). Reoperation of an aortic valve replacement with or without valvular annulus enlargement was required in four patients because of a small annulus with aortic insufficiency or infective endocarditis. Infective endocarditis was a major cause of late mortality (n = 1) and morbidity (n = 1), but the remaining eight patients have been asymptomatic. Thus, although this lesion is relatively rare in Japan, the typical discrete type may be more common than previously believed. While a relief operation is associated with low early mortality, the palliative aspect regarding pathology of the aortic valve should not be underestimated, including poor growth of the valve annulus, deterioration of aortic insufficiency, and infective endocarditis. The most appropriate operative procedure for reoperation remains to be evolved.

Adolescent↗

PubMed1999

Mitral valve replacement in patients younger than 6 years of age.

UNLABELLED: We present our experience in mitral valve replacement (including left-sided tricuspid valve in corrected transposition) in patients younger than 6 years of age. The long term results were examined with special focus on re-replacement of the valve. Between 1974 and 1995, we performed mitral valve replacement in 14 patients younger than 6 years of age, with no operative mortality. There were 3 late deaths, caused by endocarditis, valve thrombosis, and congestive heart failure, respectively. The five-year-survival rate after primary replacement was 85%, and the ten-year-survival rate was 75%, using Kaplan-Meier analysis. Ten patients (11 occasions) required repeated mitral valve replacements at 2 months to 17 years after the original replacement. The indication for the second or third mitral valve replacement was paravalvular leakage (2 patients), valve thrombosis (1 patient), degeneration in the porcine prosthesis (3 patients), and patient outgrowth of the original small prosthesis (5 patients). Again there was no operative mortality. One patient who suffered from multiple occasions of valve thrombosis died at two years after the second replacement. All patients who had outgrown the prosthetic valve received larger prosthesis at the second replacement than at the primary replacement. The actuarial percentage of freedom from valve-related events at 3 years, 5 years, and at 10 years, was 50%, 37%, and 8%, respectively. CONCLUSIONS: Mitral valve replacement in patients younger than 6 years of age can be performed relatively safely, but meticulous follow-up and appropriate decision making for re-replacement is mandatory for the long-term survival of these patients.

Child↗

PubMed1999

Prognosis of Marfan and non-Marfan patients with cystic medial necrosis of the aorta.

The characteristics and prognosis of patients with cystic medial necrosis of the aorta were reviewed. Subjects were 46 patients who underwent aortic and/or aortic valve surgery between August 1965 and October 1994. All had histologically documented cystic medial necrosis including 22 Marfan patients. The patients with Marfan syndrome were substantially younger (median age, 32 vs 50 years; p < 0.05), and experienced annulo-aortic ectasia more frequently {81% (17/22) vs 46% (11/24); p < 0.05} than those without the syndrome. Sixty-eight percent (15/22) of the Marfan patients and 63% (15/24) of the non-Marfan patients experienced complications with aortic dissection, although not to a significant degree. The hospital mortality rate was 14% (3/22) in the Marfan group and 21% (5/24) in the non-Marfan group, which was also not significant. Of the 38 survivors, developments in the health of 37 were completely followed-up until October 1997. The cardiovascular event-free rate for Marfan patients at 10 years (28%) was lower than that for non-Marfan patients (68%, p = 0.057), whereas the actuarial survival rates at 10 years were nearly equal (72% for the Marfan patients and 74% for the non-Marfan patients). Reoperation was the first cardiovascular event in 77% (10/13) of the Marfan patients and in 14% (1/7) of the non-Marfan patients (p < 0.05). Cardiovascular event was the main cause of late death both for Marfan patients (80%; 4/5) and for non-Marfan patients (86%; 6/7). In conclusion, independent of the presence of Marfan syndrome, careful follow-up is necessary for patients with cystic medial necrosis of the aorta to eliminate serious late complications.

Adolescent↗

PubMed1999

Effects of arteriovenous shunt on ventricular function in dog.

BACKGROUND: The bidirectional cavopulmonary shunt has been increasingly accepted as an interim step to the Fontan operation. However, the effect(s) of chronic volume overload on ventricular function are not yet well understood. METHODS: Twelve mongrel dogs, with (chronic volume overload group), or without (control group) a femoral arteriovenous shunt created 8 weeks before the assessment, were subjected to a right heart bypass from the right atrium to the proximal pulmonary trunk. Nonpulsatile perfusion via the bypass was achieved using a centrifugal pump and cross-clamping of the pulmonary trunk. Left ventricular function was evaluated using the end-systolic elastance and the Doppler flow pattern on echocardiograms (epicardiac and transesophageal, simultaneously) during acute volume loading. RESULTS: The left ventricular weight and the left ventricular weight/end-diastolic volume ratio showed no change from control values. The sum of the isovolumetric contraction time and the isovolumetric relaxation time divided by the ejection time remained constant during acute volume loading in the chronic volume overload group, while an increase was demonstrated in the control group. The chronic volume overload group showed a lower Ees (30.8 +/- 16.4 mmHg/cm2 vs. 107.6 +/- 70.3 mmHg/cm2, p = 0.03) than the control group. CONCLUSIONS: The global ventricular performance changed with chronic adaptation to the arteriovenous shunt, and became resistant to acute volume loading. Left ventricular contractility under nonpulsatile pulmonary perfusion was impaired by chronic volume overload, which is deleterious to the Fontan operation.

Animals↗

PubMed1999

Effect of storage temperature on cell viability in cryopreserved canine aortic, pulmonic, mitral, and tricuspid valve homografts.

We determined how long cryopreserved aortic, pulmonic, mitral, and tricuspid valve homografts could be stored in a deep freezer (-80 degrees C) without compromising fibroblast viability. Valves harvested from 20 anesthetized mongrel dogs were grouped into nonfrozen control, frozen and stored in liquid nitrogen (-196 degrees C), and frozen and stored in a deep freezer (-80 degrees C). Frozen groups were divided into subgroups and stored for 2, 4, 8, or 12 weeks. A leaflet of each valve was divided into three fragments, and fibroblast viability was analyzed by flow cytometry. Cell viability was defined as staining by fluorescent diacetate but not by propidium iodide. The viability of untreated control valves from all four sites was about 70%, decreasing to about 50% when treated with low doses of antibiotics. The viability of frozen valves stored in liquid nitrogen was about 45% without a significant difference among storage periods. The viability of valves frozen and stored in a deep freezer was significantly lower than for the liquid nitrogen group at 2 weeks for the mitral valve and at 4 weeks for other valves. These results suggest that homografts can be stored in a deep freezer for up to 2 weeks without deterioration.

Animals↗

PubMed1999

Experimental study of intracisternal administration of tissue-type plasminogen activator followed by cerebrospinal fluid drainage in the ultra-early stage of subarachnoid haemorrhage.

This experimental study evaluated the effect of intrathecal injection of tissue-type plasminogen activator followed by cisternal drainage in the ultra-early stage of aneurysmal subarachnoid haemorrhage to prevent vasospasm. Twenty Japanese white rabbits were divided into five groups. Either tPA (groups A, B, and E) or saline (groups C and D) was injected intrathecally 1 hour (groups A, B, C, and D) or 21 hours (group E) after the intrathecal injection of blood. Cerebrospinal fluid was drained 2, 4, and 6 hours after the intrathecal injection of blood (groups A, C, and E). On day 4, the angiographic caliber of the basilar artery in each group was as follows (mean +/- SD): A, 85.9 +/- 5.0%; B, 74.6 +/- 5.3%; C, 69.1 +/- 2.7%; D, 64.0 +/- 4.9%; E, 80.2 +/- 2.7% (compared with baseline). In the two groups in which CSF was drained (groups A and C), fibrinolysis with tPA significantly suppressed vasospasm. In the two groups treated with tPA (groups A and B), cisternal drainage significantly suppressed vasospasm. In the two groups treated with saline (groups C and D), however, cisternal drainage did not suppress vasospasm. Examination of the series of CSF samples (groups A and C) showed that fibrinolysis with tPA effectively cleared clots early. In the two groups treated with tPA and CSF drainage (groups A and E), early removal of subarachnoid clots reduced the degree of vasospasm. Early fibrinolysis with tPA and early removal of subarachnoid clots by drainage is effective for preventing vasospasm.

Angiography, Digital Subtraction↗

PubMed1999

Surgical angioplasty of left main coronary stenosis complicating supravalvular aortic stenosis.

We successfully treated obstruction of the main coronary artery, not aortic valve leaflet adhesion to the intimal shelf, complicating supravalvular aortic stenosis by modifying the Brom aortoplasty. An autologous pericardial patch was used to enlarge the left main coronary artery as well as the stenotic aorta. This modification allows simple and effective restoration of coronary blood flow, while maintaining the Brom procedure's merit of achieving anatomic geometry of the aortic root in such patients.

Adolescent↗

PubMed1999

Anticoagulation after valve replacement: a multicenter retrospective study.

Anticoagulant therapy after cardiac valve replacement was evaluated retrospectively in 1,200 patients attending 8 cardiac surgery clinics in the Tokyo area as part of the Tokyo Area Study on Anticoagulation After Cardiac Valve Replacement Using PT-INR (TAS). A prospective trial is also in progress and will be reported later. The prothrombin time international normalized ratio (PT-INR) was determined at the time of thromboembolic and bleeding complications in 1,200 patients. During the 5 year study period, thromboembolisms occurred in 21 patients, and bleeding complications occurred in 15 patients. In 71% of patients with thromboembolism and 47% of those with bleeding complications, the PT-INR was within the range of 1.6 to 2.8, which is the accepted therapeutic range in Japan. Therefore, the correct PT-INR therapeutic range for Japanese patients with mechanical heart valves needs to be reexamined, and data from the prospective TAS trial that is currently underway will be used for this purpose.

Adult↗

PubMed1999

Development of the Valvo pump: an axial flow pump implanted at the heart valve position.

Pulsatile artificial hearts having a relatively large volume are difficult to implant in a small patient, but rotary blood pumps can be easily implanted. The objective of this study was to show the feasibility of using the Valvo pump, an axial flow pump implanted at the heart valve position, in such cases. The Valvo pump consists of an impeller and a motor. The motor is waterproofed with a ferrofluidic seal. A blood flow of 5 L/min was obtained at a pressure difference of 13.3 kPa (100 mm Hg) at 7,000 rpm. The normalized index of hemolysis (NIH) was 0.030 +/- 0.003 (n = 3) for a blood flow of 5 L/min at a pressure difference of 13.3 kPa. The pressure resistance of the ferrofluidic seal was 37.5 kPa in a static condition and 26.3 kPa at 10,000 rpm. The seal exhibited no leaks for 41+ days against 20.0 kPa. The results showed that the Valvo pump can maintain systemic circulation with an acceptable level of hemolysis.

Animals↗

PubMed1999

Takayasu's aortitis with dissection in systemic lupus erythematosus.

A forty-seven-year-old Japanese woman under treatment for systemic lupus erythematosus (SLE), complained of severe back pain. Chest X-ray and MRI showed an aneurysmal dilatation of the ascending aorta. Subsequently an aortic replacement was performed. Microscopically, the resected aorta showed Takayasu's aortitis with chronic dissection. Both aortitis and dissection are rare events in SLE patients. To our knowledge, this is the first report of Takayasu's aortitis with dissection in a patient with SLE.

Aortic Dissection↗

PubMed1999

Embolization of cerebral arteriovenous malformations with cellulose acetate polymer: a clinical, radiological, and histological study.

OBJECTIVE: A cellulose acetate polymer (CAP) solution was hypothesized to be useful for the embolization of arteriovenous malformations (AVMs). To investigate this possibility, we analyzed the clinical, radiological, and histological results of patients with AVMs embolized by using a CAP solution. METHODS: We reviewed the cases of 11 patients with AVMs treated by embolization before surgical resection. We used two types of CAP solutions, CAP-M and CAP-L, which are mixtures of 250 mg of solid CAP and 1800 or 2250 mg of bismuth trioxide dissolved in 5.5 or 7.0 ml of dimethyl sulfoxide, respectively. After the embolization procedure, percent reduction of the nidus volume was measured, and thereafter, the clinical course and computed tomographic scans and/or magnetic resonance imaging scans were evaluated. All patients underwent surgical resection 1 to 51 days after embolization. Resected specimens were stained for light microscopic examination. RESULTS: Thirty-nine feeding vessels were embolized. The reduction rate of the nidus volume ranged from 20% to nearly 100%. Transient and persistent ischemic deficits occurred in three patients and one patient, respectively, and there were no hemorrhagic complications. All AVMs but one were completely resected by surgery. The embolized AVMs were soft enough to be easily cut and retracted. The histological examinations disclosed no or mild inflammatory reactions within 2 weeks after embolization. The internal elastic lamina was preserved in every case. Recanalization through the cast of the CAP mass was not observed until 51 days after embolization. CONCLUSION: CAP solution is a safe and useful embolic agent for AVMs.

Adult↗

PubMed1999

Flow-through thin latissimus dorsi perforator flap for repair of soft-tissue defects in the legs.

Flow-through thin latissimus dorsi perforator flaps were used in six cases with complicated defects of the legs. This flap has a small amount of latissimus dorsi muscle with a considerable amount of fatty tissue removed to make a thin flap. In addition, the flap has several branches of the subscapular vessel, which are interposed to the recipient vessels of the legs. The advantages of this thin flap are: (1) flow-through vascular reconstruction can preserve the main vessels of the damaged legs; (2) the double arterial inflows and venous drainage systems of the flap ensure safe vascularization of the flap; (3) a flow-through venous drainage system from the distal extremities can also be established to prevent congestion of the affected legs; (4) this flap is versatile (it can be either thin or large); and (5) even in emergent ischemic legs, simultaneous elevation of the flap is possible with preparation of the legs. This flow-through flap is indicated for: (1) cases with a large skin defect and obstruction of the main vessels in the leg; (2) cases with a possibility of tumor recurrence in the legs; and (3) young women or girls with a large defect in the legs, rather than the rectus abdominis musculocutaneous flap.

Adult↗

PubMed1999

Minimally invasive port-access coronary artery bypass grafting.

The Port-Access endovascular cardiopulmonary bypass system (Heartport, Inc., Redwood City, CA, USA), a recent technological innovation in minimally invasive cardiac surgery, was conducted successfully in coronary artery bypass grafting on a 69-year-old woman. The left internal thoracic artery was harvested through a limited left anterior thoracotomy and anastomosed to the left anterior descending coronary artery on a protected and arrested heart. Intraoperative coronary angiography confirmed good graft patency. The patient was discharged from the hospital in good condition 7 days after the operation. This was the first successful minimally invasive Port-Access coronary artery bypass grafting in Japan.

Aged↗