Doctor of Philosophy, Okayama University (2009)
Vadiyala Reddy, Postdoctoral Faculty Sponsor
Congenital Heart Surgery
The Damus-Kaye-Stansel operation sometimes results in deteriorating semilunar valve insufficiency. We verified the semilunar valve function after the Damus-Kaye-Stansel operation and compared the end-to-side Damus-Kaye-Stansel with the double-barrel Damus-Kaye-Stansel.Forty-seven patients who underwent the Damus-Kaye-Stansel operation between June 1993 and August 2008 were retrospectively reviewed. Any patient who underwent a Norwood-type operation was excluded. The median age at operation was 19 months (range, 0-276 months). Forty-five patients were Fontan candidates. Thirty-nine patients underwent pulmonary artery banding before the Damus-Kaye-Stansel operation. Twenty-two patients had undergone an arch repair previously. The semilunar valve function was evaluated by echocardiography.Thirteen patients underwent the end-to-side Damus-Kaye-Stansel operation, and 34 patients underwent the double-barrel Damus-Kaye-Stansel operation. The mean follow-up period was 71 ± 50 months (range, 1-188 months). Although there were 4 deaths, no death was related to the Damus-Kaye-Stansel procedure. Two of the patients with early death could not undergo a postoperative evaluation of the semilunar valves. The semilunar valve regurgitation mildly deteriorated in 7 patients (pulmonary regurgitation in 5 patients and aortic regurgitation in 2 patients). Pulmonary regurgitation deteriorated from none to mild in 1 patient, none to trivial in 2 patients, and trivial to mild in 2 patients. Both deteriorations in aortic regurgitation ranged from none to trivial. Semilunar valve regurgitation did not affect patients' circulatory condition. The end-to-side Damus-Kaye-Stansel operation more frequently caused a deterioration in pulmonary regurgitation than the double-barrel Damus-Kaye-Stansel operation (4/11 vs 1/34, P = .001). No surgical intervention for a systemic ventricular outflow obstruction was observed in the follow-up period.The double-barrel Damus-Kaye-Stansel operation was found to be superior to the end-to-side Damus-Kaye-Stansel operation for the prevention of postoperative pulmonary regurgitation.
View details for DOI 10.1016/j.jtcvs.2010.06.007
View details for Web of Science ID 000285407500034
View details for PubMedID 20637476
The anatomy of a persistent left superior vena cava (SVC) to the left atrium (LA) without the innominate vein can make it challenging to complete intracardiac repair. We reviewed our five cases of the direct end-to-side anastomosis of SVCs to facilitate anatomical repair of SVC-right atrial connection for biventricular repair. Diagnoses were two partial atrioventricular septal defect with left isomerism, one complete atrioventricular septal defect (CAVSD) with left isomerism, one CAVSD without isomerism and one atrioventricular discordance and double outlet right ventricle with right isomerism. Mean age at the operation was 20+/-23 months (4-58 months) and body weight was 7.8+/-3.4 kg (4.8-12.7 kg). After completion of intracardiac repair, the SVC to LA was divided and end-to-side anastomosed to the SVC to the right atrium during cardiopulmonary bypass. No early or late death occurred during follow-up of 14.4+/-6.9 months (7-23 months). None of the patients developed an obstruction at the anastomosis site of the SVCs. The direct end-to-side anastomosis of SVCs achieved an excellent anatomical SVC-right atrium connection in complex congenital heart diseases.
View details for DOI 10.1510/icvts.2009.230581
View details for PubMedID 20439305
The purpose of this study was to establish a useful cut-off level for performing an original Rastelli-type operation in patients with transposition of the great arteries (TGA)/ventricular septal defect (VSD) or double outlet right ventricle (DORV). A total of 43 patients with TGA/VSD or DORV who underwent an original Rastelli-type operation in this institute between March 1993 and January 2009 were reviewed retrospectively. These patients were divided into two groups using the length between the top of the interventricular septum and the aortic valve (IVS-AV length); Group A; IVS-AV length <80% of normal left ventricular end-diastolic diameter (LVDd). Group B; IVS-AV length > or =80% of normal LVDd. Group A had a significantly better survival than Group B (100% vs. 56%, P=0.001). The cardiac event-free survival were 89.1% at 7.2 years in Group A and 26.3% at 8.4 years in Group B (P<0.0001). The Group B had a higher incidence of left ventricular outflow tract obstruction (LVOTO; 3% vs. 33%, P=0.02). The IVS-AV length was found to be a significant risk factor for mortality and LVOTO. The IVS-AV length should, therefore, be taken into consideration when selecting the optimal surgical procedures for these patients.
View details for DOI 10.1510/icvts.2009.223982
View details for PubMedID 20207706
Whether chronic hypoxia attenuates myocardial ischemia-reperfusion injury remains controversial because conflicting data have been reported probably due to the existence of many factors influencing the functional recovery of hearts. These factors include the differences of species, the time at which hypoxia begins, the degree of hypoxia, and so on. Regarding chronic hypoxia from birth, so far the only available data are based on findings in rabbit hearts. The purpose of this study was to describe the effect of chronic hypoxia from birth on myocardial reperfusion injury in the rat heart.Normoxic hearts were obtained from rats housed in ambient air for 6 weeks (normoxic group); hypoxic hearts were obtained from rats housed in a hypoxic chamber (13%-14% oxygen) from birth for 6 weeks (hypoxic group). Isolated, crystalloid perfused working hearts were subjected to 30 min of global normothermic ischemia followed by 15 min of reperfusion; functional recovery was then measured in the two groups. The excretion of cyclic guanosine monophosphate (cGMP) in the coronary drainage was measured at the end of the preischemia and reperfusion periods.The percent recovery of the left ventricular developed pressure and the first derivative of left ventricular pressure were significantly better in the hypoxic group than in the normoxic group. cGMP excretion in the coronary drainage was significantly increased during both the preischemia and reperfusion periods.Chronic hypoxia from birth increased myocardial tolerance to ischemia-reperfusion injury with increased cGMP synthesis in the isolated heart model in rats.
View details for DOI 10.1007/s11748-009-0497-y
View details for PubMedID 20401710
The high-flow management of cardiopulmonary bypass (CPB; >or=2.4 L/min/m(2)) is a standard strategy used at this institute for children with pulmonary atresia (PA) due to a fear that the blood flow may be diverted by the major/minor aortopulmonary-collateral-arteries and hypervascularization due to long-term hypoxia. The purpose of this study was to describe the validity of high-flow management in children with PA. The CPB records of 23 children with PA who underwent a definitive biventricular repair between Feb 2006 and Nov 2008 were retrospectively reviewed. The mean age at the operation was 33 +/- 22 months. The blood-pressure during bypass was controlled with the same protocol. The mean cooling-temperature was 28.4 +/- 3.7 degrees C. The mean minimum hematocrit was 25.0 +/- 3.4%. The mean maximum bypass flow index at the initiation, the mean maximum flow index during aortic cross-clamping, the mean minimum flow index during aortic cross-clamping, and the mean maximum flow index after rewarming were 3.1 +/- 0.5, 3.1 +/- 0.5, 2.6 +/- 0.4, and 3.2 +/- 0.4 L/min/m(2), respectively. The higher bypass flow indexes significantly correlated with the lower serum lactate levels. The lowest oxygen delivery during CPB had significant influences on the urine output during bypass (R = 0.547, P = 0.007), the serum lactate levels at the end of CPB (R = -0.442, P = 0.035), and the postoperative thoracic effusion (R = -0.459, P = 0.028). A bypass flow index of 2.4 L/min/m(2) may not be sufficient and the maximum requirement of bypass flow index may be 3.2 L/min/m(2) or more in this patient population.
View details for DOI 10.1111/j.1525-1594.2009.00895.x
View details for Web of Science ID 000272127800003
View details for PubMedID 19817735
Careful rewarming of perfusion blood following cardiopulmonary bypass surgery is critical to a successful outcome, but the optimal rewarming strategy is not clear. The purpose of this study was to derive a formula for a rewarming index (defined as [rewarming time x perfusion flow]/[body weight x body surface area]) that would enable the calculation of the ideal rewarming conditions for pediatric cardiopulmonary perfusion. We retrospectively investigated 220 pediatric cardiopulmonary bypass operations conducted from July 2005 to June 2008 in Okayama University Hospital, Japan. We determined the formula as Phi = (T x Q)/(R x S) = |0.9127P - 0.0152|, where Phi = rewarming index, T = rewarming time (min), Q = perfusion volume (L), R = body weight (kg), S = body surface area (m(2)), and P = temperature gap (right angle). The formula will help those who perform pediatric cardiopulmonary bypass surgery to establish ideal perfusion flow conditions and to control physiological temperature during rewarming.
View details for DOI 10.1111/j.1525-1594.2009.00945.x
View details for Web of Science ID 000272127800004
View details for PubMedID 20021468
Although a staged Fontan strategy allows for an excellent outcome in high-risk patients, an impaired ventricular function remains a significant factor of early/late mortality and morbidity. This study evaluated the clinical outcome of the Fontan operation in patients with impaired ventricular function.A retrospective review was performed on 217 patients who had undergone the Fontan operation between 1991 and 2007.Twenty-nine (13%) of the 217 patients had an impaired ventricular function (ejection fraction (EF) <50%). The median age at the time of the operation was 3 (range: 1-31 years) years. There were five adult patients. The ventricular morphology was right in 20 patients (including five hypoplastic left heart syndrome (HLHS)) and others (left and two-ventricle) in nine patients. Heterotaxy syndrome was present in eight patients. Previous surgical interventions included bidirectional Glenn anastomoses in 24, modified Blalock-Taussig shunts in two and pulmonary artery banding in two. The preoperative EF was 43+/-6%. Significant (moderate or severe) atrioventricular valve regurgitation was noted in four patients. The percutaneous oxygen saturation (SpO(2)) was 82+/-5%. The pulmonary artery pressure and pulmonary artery index were 11+/-3 mmHg and 296+/-102 mm(2)m(-2), respectively. All 29 patients underwent the Fontan operation without any early mortality. There were two late mortalities and two re-operations. EF was maintained at 59+/-15% at a median follow-up of 7.5 (range: 1-19) years. The percent normal systemic ventricular end-diastolic volume decreased from 174+/-95% to 124+/-39% (p<0.05). The SpO(2) increased to 92+/-2%. The mean cardiothoracic ratio in chest X-ray and B-type natriuretic peptide were 51% (range: 35-68%) and 22 pgml(-1) (range: 9-382 pgml(-1)), respectively. Three patients developed congestive heart failure, seven had arrhythmia and two developed protein-losing enteropathy. The New York Heart Association (NYHA) class functional class is I in 21 patients, II in five and III in one.Acceptable clinical outcomes were observed at an intermediate follow-up of the Fontan operation in patients with an impaired ventricular function.
View details for DOI 10.1016/j.ejcts.2009.04.042
View details for Web of Science ID 000270644100013
View details for PubMedID 19713119
This study evaluated the effects of chronic hypoxia from birth on the resistance of rat hearts to global ischemia, with special emphasis on the duration of hypoxia. Male Wistar rats were housed from birth for 4 weeks or 8 weeks either in a hypoxic environment (FiO2 = 0.12) or in ambient air (8 animals for each group). Isolated rat hearts were perfused for 40 min with oxygenated Krebs-Henseleit buffer, subjected to 20 min global no-flow ischemia at 37, and then underwent 40 min of reperfusion. A non-elastic balloon was inserted into the left ventricle and inflated until the pre-ischemic LVEDP rose to 8 mmHg. Cardiac function was measured before and after ischemia. The post-ischemic percent recovery of LVDP in hypoxic hearts was worse than in normoxic hearts (4 weeks:55+/-7 vs. 96+/-3%, p0.01;8 weeks:40+/-5 vs. 92+/-4%, p0.01), and was worst in the 8-week-hypoxic hearts. Similarly, the percent recovery of dP/dt in the hypoxic hearts was lower than in the normoxic hearts (4 weeks:51+/-5 vs. 96+/-7%, p0.01;8 weeks:31+/-6 vs. 92+/-7%, p0.01), and was lowest in the 8-week-hypoxic hearts. In conclusion, cyanotic myocardium revealed an age-dependent vulnerability to ischemia-reperfusion injury in a chronic hypoxic rat model.
View details for Web of Science ID 000271132000003
View details for PubMedID 19893599
This retrospective study analyzed the current practice of blood transfusion-free open-heart surgery in 536 children weighing 5-20 kg undergoing surgery between 2004 and 2007. A miniaturized cardiopulmonary bypass (CPB) circuit was used (priming volume; 300 ml for the flow rate <1,500 ml/min; 550 ml for the flow rate of 1500-2300 ml/min). Modified ultrafiltration was routinely performed. Criteria for blood transfusion during CPB included a hematocrit of <20% and/or mixed venous oxygen saturation of <65%. Transfusion during CPB was avoided in 264 (49.3%) of the 536 patients (5-10 kg group, 29.0%; 11-15 kg group, 67.4%; 16-20 kg group, 80.8%). There was no neurological complication related to hemodilution. Multiple logistic regression analysis revealed that body weight, preoperative hematocrit, priming volume of CPB circuit, CPB time, and lowest hematocrit during CPB predict requirement of blood transfusion (p < 0.01). Transfusion rate was lowest in the atrial septal defect group (5.6%) and highest in tetralogy of Fallot group (78.7%), being associated with complexity of diagnosis and procedure required. Blood transfusion-free open-heart surgery may be achieved in the half of the patients weighing 5-20 kg, and further miniaturization of CPB circuit and refinement of perfusion strategy might reduce transfusion rate in patients <10 kg and/or with complex congenital heart disease.
View details for DOI 10.1097/MAT.0b013e31819742f0
View details for Web of Science ID 000265895100023
View details for PubMedID 19282750
Adult patients who do not fulfill the classical Fontan criteria now undergo total cavopulmonary connection (TCPC). However, limited information is available on the results for high-risk adult TCPC.Twenty-five consecutive adult patients (aged 16 years or more) who underwent TCPC were retrospectively reviewed. The mean age at operation was 27 +/- 9 years (range, 16 to 52). The following items were considered as the potential risk factors according to previous reports: (1) aged more than 30 years (7 of 25); (2) heterotaxy (9 of 25); (3) systemic ventricular ejection fraction less than 50% (6 of 25); (4) atrioventricular valve regurgitation moderate or greater (6 of 25); (5) pulmonary arterial index less than 200 (7 of 25); (6) mean pulmonary arterial pressure 15 mm Hg or greater (3 of 25); (7) pulmonary arterial resistance 2.0 wood units or greater (11 of 25); (8) arrhythmias (13 of 25); (9) protein-losing enteropathy (3 of 25); (10) New York Heart Association (NYHA) functional class III or greater (9 of 25); (11) previous Fontan procedure (10 of 25); (12) systemic ventricular outflow obstruction (1 of 25); and (13) end-diastolic pressure of the systemic ventricle 11 mm Hg or higher (4 of 25).The mean follow-up period was 57 +/- 45 months (range, 0 to 154). All patients had at least 2 risk factors (range, 2 to 8). There was 1 early death and 2 late deaths. Comparing the late survivors and nonsurvivors, no statistical significance was identified in the above risk factors. However, the patients with 6 or more risk factors had a significantly higher mortality rate than patients with fewer than 6 risk risk factors (p < 0.01). Age (p = 0.08), NYHA class (p = 0.13), and protein-losing enteropathy (p = 0.08) may be risk factors for late death.The majority of the adult TCPC candidates tolerated the TCPC procedure in the early postoperative period. However, the accumulation of risk factors influences late mortality.
View details for DOI 10.1016/j.athoracsur.2008.10.040
View details for Web of Science ID 000262612600033
View details for PubMedID 19161780
The purpose of the present study was to evaluate the effect of modified ultrafiltration (MUF) on neonates with transposition of the great arteries (TGA) undergoing arterial switch operation.The current study included 36 neonates who underwent an arterial switch operation between 1998 and 2006. Arterio-venous MUF was done in 15 patients (MUF-treated group) and the other 21 patients were controls. Parameters included hematocrit, hemodynamics, pulmonary function, drain loss, leak of peritoneal fluid, length of intubation, and intensive care unit (ICU) stay. The hematocrit increased from 34+/-2% to 47+/-4% in the MUF-treated group. Blood pressure in the MUF-treated group was significantly increased without any change of central venous or left atrial pressure. Post-operative oxygenation in the MUF-treated group was greater than that of the control group (P/F ratio: 258+/-92 vs 170+/-100 mmHg, p<0.05), which did not contribute to decrease in intubation time (54+/-33 vs 52+/-29 h, p=NS). Post-operative chest drain loss and peritoneal fluid leak were comparable. The ICU stay in the MUF-treated group was significantly shorter than that in the controls (101+/-34 vs 139+/-42 h, p<0.05).MUF brought improvement in blood pressure and gas exchange capacity and subsequent shorter ICU stay. MUF did not have significant impact on intubation time and capillary leak.
View details for Web of Science ID 000258798900015
View details for PubMedID 18724025
A 35-year-old man with a history of total correction of tetralogy of Fallot (TOF) fell down while riding a bike and experienced blunt cardiac rupture. His vital signs were stable because the bleeding was limited by an adhesion caused by the previous operation. Chest computed tomography clearly displayed the ruptured points, and an emergency operation was performed. Because a pneumothorax was suspected, a cardiopulmonary bypass was established with a femorofemoral bypass while the patient was conscious before artificial ventilation was initiated. Two ruptured points were detected on the anterior wall of the right ventricle and were repaired by suturing. The patient recovered and was discharged without any major complications 40 days after the operation. This is the first published case of blunt cardiac rupture after total correction of TOF.
View details for DOI 10.1007/s11748-007-0206-7
View details for PubMedID 18340514
We report a case of 75-year-old man who underwent an apicoaortic bypass for severe aortic stenosis. The patient had a porcelain aorta accompanied by a severely calcified aortic annulus. We used a woven polyester vascular graft instead of a rigid apical connector because the latter material cannot be obtained in Japan. Postoperative examination showed no compression or stenosis in the apical outflow. A woven polyester vascular graft is therefore considered suitable for an apicoaortic bypass.
View details for PubMedID 17642277
We describe a successful case of surgical treatment for anomalous left coronary artery from the pulmonary artery (ALCAPA) syndrome with severe left ventricular dysfunction. Because of the severe left ventricular dysfunction, we planned to use an extracorporeal membrane oxygenation for heart support until a satisfactory recovery had been established. The left ventricular function significantly recovered in a few days, and the patient could be discharged without any complications.
View details for Web of Science ID 000244432400006
View details for PubMedID 17332841
A lateral tunnel-total cavopulmonary connection (LT-TCPC) using a right atrial (RA) free wall is the first choice of treatment for patients with a small body weight in this institute. Whether the growth of the LT is appropriate or not according to the growth of the body remains controversial. In addition, the optimal initial diameter of an LT is unknown. The purpose of this study was to verify the growth of the LT.Ninety-one patients of a total of 267 TCPC cases underwent an LT-TCPC at less than 5 years of age in this institute between March 1991 and June 2008. The data on 47 of the 91 patients, which were available to investigate the LT growth, were retrospectively reviewed. The mean age at LT-TCPC was 37+/-11 months (16-57 months). The mean body weight at TCPC was 12.4+/-2.4 kg (7.6-20.0 kg). The initial LT diameter was determined with Hegar's sizer of the estimated half-pulmonary arterial (PA) diameter, which is a diameter that results in half of the dimension of the normal pulmonary valve. The measured maximum LT diameter (mm) divided by the estimated half-PA diameter (mm) was considered as the LT index. The size of the LT was evaluated using either echocardiography or angiography.The mean follow-up period was 7.4+/-3.5 years (1.6-13.5 years). The LT index was initially 2.0+/-0.7 (1.3-4.5), 2.0+/-0.4 (1.3-3.2) at 1 year after operation, 2.1+/-0.5 (1.5-3.2) at 5 years after operation, 1.9+/-0.4 (1.5-2.8) at 10 years after operation and 2.1+/-0.5 (1.6-2.5) at 13 years after operation, respectively.LT growth suitable for the body growth can be expected. Although there was some variation in the initial LT diameter, the LT index tended to converge at 2.0 with growth.
View details for DOI 10.1016/j.ejcts.2010.01.014
View details for Web of Science ID 000279744400013
View details for PubMedID 20353894