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Biomedical subjects

Keishu Yasuda

Publications and source records attributed to Keishu Yasuda.

At least 37 records · Page 2Linked to original sources

Impact of papillary muscles approximation on the adequacy of mitral coaptation in functional mitral regurgitation due to dilated cardiomyopathy.

PURPOSE: We report early outcome of our modified papillary muscles approximation (PMA) as an adjunct to mitral annuloplasty (MAP) by analyzing the mitral coaptation zone echocardiographically and clinical outcome in three different procedures. METHODS: Mitral valve coaptation depth (MVCD) and tenting area were measured in patients with ischemic (n=8) or non-ischemic (n=22) dilated cardiomyopathy (ICM or non-ICM) undergoing either of following: Group I: isolated left ventricular volume reduction (LVVR) (n=11), Group II: PMA plus LVVR (n=14), Group III: isolated PMA (n=5). Clinical outcome including cardiac function were also investigated. RESULTS: Thirty-day mortality was 6.7%. Postoperative data in overall survivors showed significant improvement of ejection fraction (EF) (from 19+/-7 to 32+/-9%), left ventricular end-diastolic volume index (LVEDVI) (from 189+/-74 to 132+/-41 mL/m2), and left ventricular diastolic dimension (LVDd) (from 73+/-8 to 65+/-6 mm) (p<0.001). The overall preoperative MVCD (mm) and tenting area (cm2) was 10.4+/-2.8 and 2.4+/-0.6, respectively, which were both significantly reduced to 5.6+/-2.5 and 0.8+/-2.4 postoperatively (p<0.001). In comparison of the degree (%change) of improvement, Group II and III showed favorable effects on tethering force, compared with Group I. CONCLUSION: Our modified PMA is a relatively safe method to have the potential for improving tethering of the mitral valve and clinical outcome in evaluating mitral coaptation zone.

Cardiomyopathy, Dilated↗

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↗

Experimental studies on artificial blood usage for hemodilution during cardiopulmonary bypass.

BACKGROUND: Although hemodilution is usually utilized during cardiopulmonary bypass (CPB), hemodilution can cause adverse effects such as hypotension and hypoxia. The purpose of this study was to evaluate a novel perfluoro-octyl bromide (PFOB) emulsion, one of perfluorochemicals (PFCs) emulsions, administered during hemodilution CPB. METHODS: Fifteen dogs were subjected to CPB for 2 hours under mild hypothermia. Animals were divided into three groups; control group, hemodilution group and PFOB group. During the experiment, hemodynamics, complete blood count and blood chemistry were monitored. In addition, serum complement titer (CH50), bradykinin and histamine concentrations were also measured. RESULTS: Heart rate (HR) was markedly elevated in the hemodilution groups (p<0.05). Mean arterial pressure (MAP) did not change in the three groups. White blood cell (WBC) and platelet (PLT) count did not significantly differ among the three groups. Plasma lactate concentration was markedly elevated only in hemodilution group during late phase of CPB (p<0.05). In the hemodilution group, CH50, bradykinin and histamine, were markedly elevated during the CPB and just after CPB (p<0.05). CONCLUSIONS: The present study demonstrated possible benefits of the new PFC emulsion during cardiac surgery by counteracting the adverse effects of hemodilution during CPB.

Analysis of Variance↗

A case of mitral valve replacement with a collar-reinforced prosthetic valve for heavily calcified mitral annulus.

Mitral valve replacement in the presence of extensive calcification of the mitral annulus is a technical challenge. Dense calcification of the annulus can cause a great difficulty in the insertion of a prosthetic valve and later periprosthetic leakage. A radical calcium debridement may cause left circumflex coronary artery injury, atrioventricular rupture, and thromboembolic events. We report a case of a 65-year-old woman suffering from mitral regurgitation with a severely calcified mitral annulus. She underwent mitral valve replacement using a collar-reinforced prosthetic valve, which allowed the surgeon to safely insert a prosthetic valve, avoiding the calcification completely without any major complications. We recommend this method as a feasible technique for mitral valve replacement in the presence of heavily calcified or disrupted fragile mitral annulus.

Aged↗

Successful endovascular stent-graft treatment for an aortoesophageal fistula caused by a descending thoracic aortic aneurysm: report of a case.

Conventional surgery for aortoesophageal fistula (AEF) is technically difficult, and is associated with high morbidity and mortality. We report a case of primary AEF caused by a descending thoracic aortic aneurysm, which was successfully treated with an endovascular stent-graft technique. The patient has been followed up for 3 years with no signs of infection.

Aged↗

Successful arterial reconstruction with collateral artery bypass for a femoral artery aneurysm: report of a case.

The outcome of surgery for femoral artery aneurysms is dependent on the preoperative status of the runoff vessels. We report a case of a femoral artery aneurysm complicated by thromboembolic obstruction of the distal superficial femoral and profunda femoris arteries. Fortunately, the collateral arteries were viable runoff vessels for restoring adequate blood flow to the limb.

Aged↗

Use of bioresorbable membrane to prevent postoperative small bowel obstruction in transabdominal aortic aneurysm surgery.

PURPOSE: To evaluate the efficacy of Seprafilm (Genzyme, Cambridge, MA, USA), a bioresorbable membrane, in preventing or reducing early postoperative small bowel obstructions after transabdominal abdominal aortic aneurysm (AAA) surgery. METHODS: Fifty-one patients underwent aortic reconstruction via a midline transperitoneal approach for infrarenal AAAs. Twenty-one patients underwent surgery with Seprafilm (Seprafilm group) and the remaining 30 patients did not (control group). The incidence of early small bowel obstruction was examined, and the time before liquid and solid diet were resumed was also compared to assess postoperative paralytic ileus. RESULTS: Patients in the Seprafilm group resumed a liquid diet on postoperative day (POD) 2.4 +/- 1.1 and a solid diet on POD 4.0 +/- 1.3, whereas the patients in the control group resumed a liquid diet on POD 3.3 +/- 1.9 and a solid diet on POD 5.4 +/- 3.4. These values were not significantly different between the two groups; however, the incidence of early postoperative small bowel obstruction was significantly lower ( P < 0.05) in the Seprafilm group (0/21) than in the control group (6/30). CONCLUSION: These findings suggest that Seprafilm may help to prevent early postoperative small bowel obstructions after transabdominal AAA surgery.

Absorbable Implants↗

Postoperative renal function after elective abdominal aortic aneurysm repair requiring suprarenal aortic cross-clamping.

PURPOSE: To examine postoperative renal function after suprarenal aortic cross-clamping performed without renal hypothermia in patients undergoing elective abdominal aortic aneurysm (AAA) surgery. METHODS: Between 1991 and 2000, 18 patients underwent surgery for a juxtarenal AAA, which required a suprarenal aortic cross-clamp. All AAAs were repaired with a proximal anastomosis just below the renal arteries. We divided the patients into two groups according to the duration of the renal ischemia: <45 min (n = 12) and > or =45 min (n = 6). The postoperative changes in renal function were analyzed. RESULTS: There were no hospital deaths and none of the patients needed permanent hemodialysis. The postoperative peak in the serum creatinine level after suprarenal cross-clamping for > or =45 min was significantly higher than that after cross-clamping for <45 min. The percentage changes in serum creatinine and blood urea nitrogen were correlated positively with the duration of renal ischemia, and were significantly greater in the group with renal ischemia of <45 min than in the group with prolonged renal ischemia (> or =45 min). CONCLUSIONS: Suprarenal aortic cross-clamp without performing renal hypothermia is safe and able to be tolerated well by the patient during elective AAA surgery, although careful attention must be paid to limiting the period of renal ischemia.

Acute Kidney Injury↗

Hemodynamic changes in stripping operation or saphenofemoral ligation of the greater saphenous vein for primary varicose veins.

The aim of this study was to assess early hemodynamic improvement after a stripping operation or saphenofemoral ligation by means of air plethysmography. This prospective study assessed 109 limbs of 71 patients treated between May 2000 and December 2001 for primary varicose veins due to greater saphenous insufficiency. Eighty-nine limbs were treated by stripping surgery (stripping group), and 20 limbs were treated with saphenofemoral ligation (saphenofemoral ligation group). To evaluate venous hemodynamic changes, air plethysmography was performed before surgery and 7-14 days after surgery. A significant decrease and normalization of the venous filling index and residual volume function was observed in the two groups. A decrease in venous volume was observed in the ligation group, but the change was not statistically significant. In contrast, a significant decrease in venous volume was observed in the stripping group. The ejection fraction was not improved in either of the groups. From these results we conclude that hydrostatic forces can be controlled by means of a stripping operation as well as by saphenofemoral ligation in the early postoperative period.

Case-Control Studies↗

Minimal access surgery for the repair of simple congenital heart defects: factors affecting hospital stay after surgery.

OBJECTIVE: We reviewed our experience of minimal access surgery to elucidate the efficacy and safety of this approach and determine the factors affecting hospital stay. METHODS: Seventy-seven patients (age, 11.8 +/- 11.0 years), with body weight of more than 10 kg, were operated using various forms of minimal access approach for repair of simple congenital heart defects [atrial septal defect (ASD) in 40, ventricular septal defect in 37]. These included lower partial sternotomy (n = 68) and mini-thoracotomy (n = 9, ASD only) with limited skin incision of 4-11 cm. The anesthetic protocol was modified to wean all patients from ventilator soon after operation. The protocol of discharge from hospital (critical pass) was 14 days in the early period (n = 30) and 10 days in the late period (n = 47). RESULTS: There were no hospital or late death, and no hospital re-admission. None of patients required blood transfusion. The endotracheal tube was extubated in the operating room in 48 cases (62%). Twenty-four patients (31%) failed to fulfill conditions of the critical pass. Univariate analysis of factors affecting unfavorably the critical pass demonstrated that the median approach, retention of pericardial effusion and social reasons were statistically significant, while an opened pleura and aortic cross-clamp time were marginally significant. Multivariate analysis indicated that the retention of pericardial effusion was the only significant factor that failed critical pass [p = 0.007, odds ratio (OR) 5.7, 95% confidence interval (CI) 1.61 -19.8]. In addition, a pericardio-pleural fenestration was the only significant factor that affected favorably the pericardial effusion (p = 0.035, OR 0.2, 95% CI 0.47-0.89) by multivariate analysis. CONCLUSIONS: Our experience demonstrated that minimal access surgery of the simple congenital heart defects provided excellent cosmetic results. Retention of pericardial effusion, possibly due to pericarditis, was a major risk factor of the prolonged hospital stay. The pericardio-pleural fenestration could reduce the risk of retention of effusion.

Adolescent↗

A new method for graft tailoring in hemiarch replacement.

We describe a method of graft tailoring in hemiarch replacement that can accommodate long elliptical distal anastomosis and the right angle between the arch and ascending aorta without kinks, resulting in a more physiologic shape of the neoaorta. The distal end of the graft is beveled superiorly, to spare the origins of brachiocephalic vessels as in the standard bevel technique, but the incision line is curvilinear to form a concave cut end. Once the distal anastomosis is completed and the concavity of the cut end is straightened, the undersurface of the graft tongue forms a lesser curvature of the arch.

Anastomosis, Surgical↗

Left atrioventricular valve regurgitation after repair of incomplete atrioventricular septal defect.

BACKGROUND: Excellent surgical results have been reported for repair of incomplete atrioventricular septal defect; however, left atrioventricular valve regurgitation (ltAVVR) is a major cause of late morbidity. We reviewed our entire experience with incomplete atrioventricular septal defect in order to investigate long-term results of ltAVVR after repair and determine the factors influencing the progression of ltAVVR in late follow-up. METHODS: Between 1983 and 2002, 61 patients underwent surgical repair of incomplete atrioventricular septal defect, including 7 patients with intermediate forms. The age of operation ranged from 1 month to 62 years old (median 5.3 years old). Thirteen patients were less than 2 years old, including 7 infants, while there were 15 adult patients. All patients underwent patch closure of the ostium primum defect. Before 1995, the cleft was left open in 7 patients and partial closure of the cleft was done in 41 patients, whereas complete closure of the cleft was performed in 9 patients since 1996. Preoperative and postoperative ltAVVR at hospital discharge and late follow-up were graded 0-IV by echographic evaluation. RESULTS: There was 1 early death and 4 late deaths with a 91% 10-year actuarial survival rate. Preoperative ltAVVR grade was I in 25 patients, II in 31 patients, III in 4 patients, and IV in 1 patient. Postoperatively, ltAVVR deteriorated in 3 patients. Left AVVR decreased in 21 patients, whereas in 37 patients it remained the same at hospital discharge. Consequently, ltAVVR remained grade II in 18 patients, grade III in 2, and there was no patient with grade IV. During the long-term follow-up, 24 patients were noted to have increased ltAVVR, including grade III in 8 patients and grade IV in 4. Reoperations for ltAVVR were required in 5 patients (8.3% of hospital survivors); valve replacement in 3 patients and valve repair in 2. Actuarial freedom from reoperation for ltAVVR was 91% at 10 years, whereas actuarial freedom from postoperative ltAVVR grade III or more was 89% at 5 years and 78% at 10 years. Multivariate analysis indicated that postoperative ltAVVR grade II or more at hospital discharge (p = 0.0032, odds ratio = 7.41, 95%CI: 1.95-28.10) was the only independent variable related to late ltAVVR, whereas age at operation, preoperative grade of ltAVVR, and the method of cleft repair were not significant risk factors. CONCLUSIONS: Left AVVR is still a significant risk in long-term follow-up. Because the postoperative grade of ltAVVR is the only independent risk factor for late ltAVVR, more efforts should be focused on left atrioventricular valve repair so as to minimize residual regurgitation, even mild regurgitation.

Adolescent↗

Tau protein in the cerebrospinal fluid is a marker of brain injury after aortic surgery.

BACKGROUND: Tau is a protein localized primarily in neurons, especially in the axonal compartment. Cerebrospinal fluid tau levels are elevated in acute stroke and head traumas. The purpose of this study is to elucidate the alterations of cerebrospinal fluid tau levels in patients with or without neurologic complication after aortic surgery. METHODS: Twenty-eight patients undergoing descending thoracic (n = 8) or thoracoabdominal (n = 20) aortic surgery were enrolled. Cerebrospinal fluid tau levels were measured before operation and at seven time points up to the 72nd postoperative hour, and were compared with cerebrospinal fluid S100B levels. RESULTS: Two patients developed brain infarction, including the one with paraplegia. In these patients, 20-fold to 100-fold tau elevation was observed, but S100B elevation was less evident in the patient without paraplegia. Three other patients developed spinal cord injury. Additional three patients suffered from temporary neurologic dysfunction of the brain. Tau levels in the latter three patients showed tenfold elevation and were higher than those in the three patients with spinal cord injury or those in the patients without neurologic complication up to 24 postoperative hours. The S100B levels were also higher in the three patients with temporary neurologic dysfunction of the brain than in the patients without neurologic complication at the conclusion of surgery. From 6 to 24 postoperative hours, they were higher in the three patients with spinal cord injury than in the patients without neurologic complication. CONCLUSIONS: These preliminary results suggest that cerebrospinal fluid tau levels reflect brain injury. Because tau levels may separate the patients with temporary neurologic dysfunction, they may serve as a useful marker of brain injury.

Adult↗

Bilateral coronary ostial patch angioplasty with autologous pericardium in Takayasu arteritis: a case requiring replacement of the aortic valve and ascending aorta.

Since the lesions and stages of Takayasu arteritis vary with each patient, surgical treatment of this disease requires meticulous planning for the timing of operation, technique, material used, and postoperative medication. We report a rare complex lesion of Takayasu arteritis, which required simultaneous repairs for aortic regurgitation, a dilated ascending aorta and bilateral coronary ostial stenosis. Such multiple lesions have not been reported previously. A 47-year-old woman was referred to us because of heart failure and chest pain. The coronary ostial stenosis were enlarged with generously sized autologous pericardial patches, and separate aortic valve and ascending aortic replacements were performed since the diameter of the Valsalva sinus was 37 mm. The postoperative course was uneventful, but steroid therapy was commenced postoperatively because inflammatory reaction remained high.

Angioplasty↗

Surgical results for active endocarditis with prosthetic valve replacement: impact of culture-negative endocarditis on early and late outcomes.

OBJECTIVE: Surgical treatment of active infective endocarditis requires not only hemodynamic repair, but also special emphasis on the eradication of the infectious focus to prevent recurrence. This goal can be achieved by the combination of aggressive debridement of infective tissue and appropriate and adequate antibiotic treatment. We reviewed our experience with active endocarditis and identified factors determining early and late outcomes, particularly focusing on the factor of culture-negative endocarditis. METHODS: Sixty seven patients with clinical evidence of active endocarditis who underwent operation between 1991 and 2001 were evaluated. The aortic valve was infected in 28 (42%), the mitral valve in 23 (34%), and multiple valves in 16 (24%). Native valve endocarditis was present in 58 (87%) and prosthetic valve endocarditis in 9 (13%). Mean follow-up was 5.7 years (range, 0.2-11.5 years). RESULTS: Microorganisms were detected in 46 (69%): Staphylococcus aureus in 9 (13%), other staphylococci in 9 (13%), streptococcus species in 19 (28%), and others in 9 (28%), whereas 21 (31%) patients had culture-negative endocarditis. Operative mortality was 17.8% (12 patients). Reoperation was required in 8 (12%), while 3 late deaths (5.5% of hospital survivors) occurred. All events, including death, reoperation, periprosthetic leak, and recurrence of infection, occurred within 2 years after operation. Actuarial freedom from reoperation, late survival, and events at 5 years were 81.6, 76.4, and 68.6%, respectively. On multivariate analysis, no independent adverse predictor was detected for hospital death, whereas the following independent adverse predictors were identified: preoperative heart failure (P=0.0375), prosthetic valve endocarditis (P=0.0391) and culture-negative endocarditis (P=0.0354) for poor late survival; culture-negative endocarditis (P=0.0354) and annular abscess (P=0066) for poor event-free survival. Freedom from events was similar between patients with Staphylococcus aureus infection (3-year freedom 55.6%) and culture-negative endocarditis (3-year freedom 47.6%), whereas events were significantly low in patients with streptococcus infection (3-year freedom 100%). CONCLUSIONS: In our analysis, no independent adverse predictor was detected for hospital death; however, culture-negative endocarditis was identified as an independent predictor for both late survival and events after surgery. Event-free survivals were similar between staphylococcus infection and culture-negative endocarditis, and all events occurred within 2 years after operation, suggesting the necessity of close follow-up during that period.

Adolescent↗

Naloxone lowers cerebrospinal fluid levels of excitatory amino acids after thoracoabdominal aortic surgery.

OBJECTIVE: Although naloxone has been used to prevent ischemic spinal cord injury (SCI), its effect on excitatory amino acids (EAAs) has not been understood. We investigated the clinical significance of naloxone by measuring EAAs in the cerebrospinal fluid (CSF) in patients undergoing thoracoabdominal aortic surgery. METHODS AND SUBJECTS: Twenty-seven patients (15 men and 12 women; mean age, 66 +/- 12 years) undergoing prosthetic replacement of the thoracoabdominal aorta (n = 19) or the descending thoracic aorta (n = 8) from April 1997 to June 2003 under distal perfusion and mild hypothermia were enrolled in this cohort study with historical controls. Their etiology was 7 dissections and 20 nondissections. In 16 patients (naloxone group), intravenous infusion of naloxone (1 microg/kg/h) was continued until the patients became alert. In the remaining 11 patients (control group) naloxone was not given. CSF drainage was used in all patients. CSF levels of EAAs, glutamate, aspartate, and glycine were measured at 6 points in time until 72 hours postoperatively, using a high-performance liquid chromatography method. RESULTS: In 5 patients with SCI (2 patients in control group, 3 in naloxone group), CSF levels of glutamate and glycine continued to increase even at 72 hours postoperatively, and were significantly more elevated than those in patients without SCI ( P < .0001, glutamate; P = .0006, glycine). Postoperative maximum levels of CSF glutamate and glycine were also significantly higher in patients with postoperative SCI than in patients without SCI (glutamate: 215.3% +/- 158.6% vs 32.9% +/- 37.3% increase from baseline, P < .0001; glycine: 309.1% +/- 218.2% vs 89.2% +/- 103.1% increase from baseline, P = .0036). CSF levels of glutamate and aspartate in naloxone group were significantly lower than those in control group ( P = .0161, glutamate; P < .0001, aspartate). Postoperative maximum level of CSF aspartate was also significantly lower in the naloxone group than in the control group (8.3% +/- 75.5% vs 119.7% +/- 120.6% increase from baseline, P = .0077). In multivariate logistic regression analysis, postoperative maximum CSF glutamate >100% from baseline ( P < .001) and postoperative maximum level of CSF glycine ( P = .005)were identified as the independent risk factors for SCI. Both SCI ( P < .001) and postoperative maximum level of CSF glycine ( P = .005) were the independent predictors for postoperative maximum level of CSF glutamate >100% from baseline. CONCLUSIONS: CSF levels of EAAs are elevated in patients with SCI. CSF glutamate is the strongest independent predictor of SCI. Naloxone is effective in lowering CSF levels of EAAs.

Adult↗

Outcome of the perioperative use of percutaneous cardiopulmonary support for adult cardiac surgery: factors affecting hospital mortality.

Percutaneous cardiopulmonary bypass support (PCPS) has become a widespread standard modality for the treatment of circulatory collapse; however, its clinical use for postcardiotomy low cardiac output syndrome (LOS) has been reported to be unsatisfactory. We reviewed the clinical outcomes of twenty-three patients undergoing cardiac surgery and treated with PCPS. Solitary coronary artery grafting was undertaken for nine patients, while three had concomitant procedures. The remaining patients underwent valvular surgery. The indications for PCPS were preoperative shock in two patients and postcardiotomy LOS or shock in twenty-one patients. All patients except one underwent an intraaortic balloon pump. Sixteen of the twenty-three patients (69.6%) were weaned from PCPS and twelve patients (52.2%) reached hospital discharge. A univariate analysis revealed that risk factors for hospital mortality were age older than seventy years (P = 0.05), PCPS running time (P = 0.017), low cardiac function at the institution of PCPS (P = 0.004), and urine output within the initial 24 h (P = 0.041). The cardiac index (CI) in survivors was improved within 24 h, and eleven of the twelve survivors were weaned off PCPS within 48 h, whereas ten of the twelve nonsurvivors required PCPS for more than 48 h (P = 0.0006). There is little possibility of weaning patients from PCPS who do not show any signs of hemodynamic recovery within 48 h after its institution. Limited use of PCPS within 48 h may be applicable for postcardiotomy patients, but other cardiopulmonary support, such as a left ventricular assist device, may be required when hemodynamic recovery is not obtained within 48 h.

Adolescent↗

Selective perfusion of the upper and lower body under different levels of hypothermia in a patient with coronary artery disease and dissecting thoracoabdominal aortic aneurysm.

Hypothermia is known to protect the myocardium and the spinal cord during ischemia. However the risk of complications increases with lower hypothermic conditions. In this paper we report a 62-year-old male patient with concomitant coronary artery disease who was surgically treated for a thoracoabdominal aortic aneurysm and an abdominal paraanastomotic pseudoaneurysm using selective perfusion of the upper and lower body under mild and deep hypothermia respectively. The patient was discharged uneventfully and only experienced transient delirium. We believe this novel modality may be a promising alternative in selected candidates.

Aortic Dissection↗