Biomedical subjects

K Sawatari

Publications and source records attributed to K Sawatari.

At least 37 records · Page 2Linked to original sources

PubMed1993

[A case of Fontan operation for complex heart disease with good post-operative course by the management of hypothermia in coming off from cardiopulmonary bypass].

A 8-year-old boy with a complex heart disease was underwent Fontan operation with Glenn operation, and had a good post-operative course by the management of hypothermia in coming off from cardiopulmonary bypass around 31 degrees C. The hypothermic therapy was thought to be effective in acute stage after Fontan operation, because it improved tachycardia, decreased the systemic metabolism, redistributed the systemic arterial blood flow and increased the urinary output.

Child↗

PubMed1993

[The limits for modified Fontan operations with AV valve regurgitation--the effect of AV valve regurgitation on the Fontan operation for single ventricle].

We performed a modified Fontan operation on 14 patients of single ventricle with AV valve regurgitation (single right ventricle: SRV 8, single left ventricle: SLV 6) until 1990. During the same period, 41 patients of single ventricle without AV valve regurgitation underwent the modified Fontan operation. To evaluate the effect of AV valve regurgitation on the Fontan operation, operative mortality, ventricular and pulmonary functions were compared between two groups. No significant differences were observed in operative mortality (7% vs 12%). There were also no significant differences of post-operative cardiac index (mean 2.6 L/min/m2 vs 2.6 L/min/m2), pulmonary vascular resistance (mean 2.3 U.m2 vs 2.2 U.m2) and preoperative ejection fraction (mean 54% vs 62%) between two groups. Therefore, the hemodynamic status of single ventricle following the Fontan operation remained almost unchanged irrespective of the presence of AV valve regurgitation. This suggested that AV valve regurgitation was not itself a contraindication of the Fontan operation, if the correct indices and time for operation were selected.

Heart Atria↗

PubMed1993

Recovery of cerebral blood flow and energy state in piglets after hypothermic circulatory arrest versus recovery after low-flow bypass.

A miniature piglet model that replicates clinical hypothermic (14 degrees C nasopharyngeal) circulatory arrest and low-flow (50 ml/kg per minute) bypass was used to study carotid blood flow with electromagnetic flow probe, cerebral blood flow by microsphere injection, cerebral metabolic rate by arteriovenous oxygen and glucose extractions, lactate production by cerebral arteriovenous difference, and cerebral edema. Data from five animals that underwent circulatory arrest and five animals that underwent low-flow bypass (aged 28.8 +/- 0.4 [mean +/- standard error of the mean] days) were analyzed. The duration of circulatory arrest and low-flow bypass was 1 hour. In a parallel study with the same animal model, phosphorus 31 magnetic resonance spectroscopy was used to assess cerebral phosphocreatine, nucleoside triphosphate (adenosine triphosphate), and intracellular pH. Five animals (aged 31.8 +/- 1.1 days) underwent circulatory arrest, and five underwent low-flow bypass. A brief phase of hyperemic carotid blood flow was seen immediately after the onset of reperfusion in the circulatory arrest group but not in the low-flow group. In the circulatory arrest and low-flow bypass groups, cerebral blood flow (percentage of baseline 71.2% +/- 8.3% and 69.1% +/- 5.8%, respectively), cerebral oxygen consumption (45.6% +/- 10.0%, 44.5% +/- 7.6%), and cerebral glucose consumption (31.5% +/- 30.7%, 83.5% +/- 24.2%) remained depressed after 45 minutes of reperfusion and rewarming to normothermia. However, after 3 more hours of pulsatile normothermic reperfusion, cerebral oxygen consumption and cerebral glucose consumption had returned to baseline. Phosphocreatine, adenosine triphosphate, and pH were maintained at or above baseline levels throughout low-flow bypass and throughout 3 hours of normothermic reperfusion. In contrast, both phosphocreatine and adenosine triphosphate became undetectable 32 +/- 3.7 minutes after onset of circulatory arrest. During and early after circulatory arrest, pH decreased to a minimum of 6.506 +/- 0.129 at 40 minutes after reperfusion. After 3 hours of normothermic reperfusion, phosphocreatine and adenosine triphosphate recovered to 98.6% +/- 9.0% and 90.1% +/- 13.5% of baseline, respectively, and pH was 7.087 +/- 0.051, similar to baseline (7.1755 +/- 0.041). In the low-flow bypass group, the disparity between the depressed level of cerebral oxygen consumption and normal high-energy phosphate levels may reflect incomplete cerebral rewarming or decreased energy consumption. In the circulatory arrest group, the parallel recovery of oxygen consumption and high-energy phosphates eventually achieving baseline levels suggests that the degree of hypothermia used provides adequate protection for acute cerebral recovery after 1 hour of circulatory arrest.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Triphosphate↗

PubMed1993

Mechanical durability of pulmonary allograft conduits at systemic pressure. Angiographic and histologic study in lambs.

We examined the mechanical durability of cryopreserved pulmonary allograft conduits at systemic pressure in lambs. Composite valveless tube grafts made of cryopreserved pulmonary allograft and a length of Dacron tube were implanted in the thoracic aortic position in 10 lambs (aged 1 month, mean weight 11.4 kg). The pulmonary allografts were harvested from similar-sized lambs (aged 1 month, mean weight 10.5 kg) at 0 to 48 hours postmortem and were cryopreserved. Recipient sheep were catheterized at 1 week (baseline) and at 1, 4, 6, 9, and 12 months postoperatively to allow changes in the diameters of the grafts to be followed up by angiography. Samples of the grafts were examined histologically at the time of harvest, at implantation after cryopreservation and thawing, and at the end of the study. At the postoperative baseline study, the pulmonary allografts had almost doubled (mean 21.1 mm) their implantation diameters (unpressurized mean 12.6 mm). During the 12-month study period, the allografts further increased their angiographic diameter by 36.2% compared with baseline (p < 0.01). One animal died at 3 1/2 months postoperatively and was found to have an aneurysm of the allograft. Five of the remaining eight lambs showed aneurysmal dilatation (more than 40% increase in diameter relative to pressurized baseline) at 12 months. Postmortem study revealed disruption at the suture line between allograft and Dacron in these five recipients. Histologic study showed much less calcification than was seen in our previous study of aortic allografts. There was loss of most of the smooth muscle, intimal and adventitial fibrous proliferation, and occasional dense lymphocytic infiltrates associated with foci of persistent smooth muscle cells. Time of harvest after donor death did not affect the histologic appearance after 12 months' implantation. Pulmonary allografts dilate substantially at systemic pressure. This characteristic has the benefit of allowing progressive enlargement with time as a recipient grows but also carries the risk of aneurysm formation, particularly pseudoaneurysm at the suture line when anastomosed with a noncompliant Dacron prosthesis.

Anastomosis, Surgical↗

PubMed1993

[Successful two-staged Jatene operation for severe right ventricular dysfunction and tricuspid regurgitation after Senning operation--a case report].

We report a seven-year-old boy who underwent a successful Jatene procedure seven years after Senning procedure. The modified Senning operation was performed for the treatment of transposition of the great arteries with intact ventricular septum at three years of age. However, he gradually showed the progressive right ventricular failure with tricuspid regurgitation after operation. When he was referred to our hospital, he was in severe right ventricular failure and showed massive tricuspid regurgitation simultaneously with the moderate degree of left ventricular failure. Staged pulmonary artery banding was applied to prepare the left ventricle for Jatene procedure in spite of the presence of left ventricular failure. The systolic pressure ratio of left ventricle to right ventricle was elevated to 0.91 by this banding although the left ventricular ejection fraction decreased from 43% to 30%. And Jatene procedure was successfully performed after three months of preparation period. Catheterization study after Jatene procedure revealed improved right and left ventricular functions with decrease of tricuspid regurgitation. We conclude that the Jatene procedure should be an ideal alternative in patient with right ventricular failure and/or tricuspid regurgitation after an atrial switch operation; the left ventricle could be prepared by an effective pulmonary banding in most instances.

Child↗

PubMed1993

[Measurement of cardiac output by Doppler echocardiography: clinical validation in pediatric patients after open heart surgery].

We compared the cardiac output obtained by pulsed Doppler echocardiography (COPW) with simultaneous thermodilution measurements (COTD) in 13 children for 33 times after open heart surgery. Good correlation (r = 0.84, slope = 1.15) of cardiac output was obtained when direct measurements of aortic diameter during operation were used in the calculations. Cardiac output was overestimated (r = 0.89, slope = 1.42) when 2 DE measurements of aortic diameter were used. Nineteen measurements of 8 VSD patients revealed good correlation (r = 0.89, slope 0.85) using direct measurement of aortic diameter, whereas 14 measurements of TOF patients showed somewhat overestimation of cardiac output (r = 0.90, slope = 1.31). In serial determinations, percent change change in COPW well correlated with COTD (r = 0.75, slope = 1.08). We conclude that accurate cardiac output can be obtained by pulsed Doppler echocardiography after pediatric cardiac surgery by measuring aortic diameter directly in operation room. Accuracy in percent change in cardiac output proved that COPW is useful especially in hemodynamically unstable patients after pediatric cardiac surgery.

Age Factors↗

PubMed1993

[Biventricular repair with a modified Glenn shunt for the hypoplastic right ventricle].

Between 1982 and 1990, 14 patients with small right ventricle underwent biventricular repair with a modified Glenn shunt. The patients consisted of 8 cases of pulmonary atresia and intact ventricular septum, 2 with pulmonary stenosis and intact ventricular septum, 3 with tetralogy of Fallot, 1 with pulmonary atresia and straddling tricuspid valve. Nine patients had one or more prior preliminary palliative procedures. Repairs consisted of a modified Glenn shunt and closure of the intracardiac and extracardiac shunt, with right ventricular outflow reconstruction in 13, and pulmonary valvotomy in 1. In nine patients superior vena cava was not ligated. There was one operative death (7%). Preoperative RVEDV ranged from 19 to 70% of normal with a mean of 36.1% of normal. Preoperative pulmonary resistance ranged from 1.6 to 5.3 unit with a mean of 2.8 unit. Preoperative PA index ranged from 102 to 444 mm2/m2 with a mean of 234.3 mm2/m2. No patients died later. Follow-up 2 to 9 year after operation showed that 9 patients were in the New York Heart Association class I and 4 were in class II. Our experience shows that this procedure can be safely done for patients, who have hypoplastic right ventricle smaller than 40% of normal and are not candidate for Fontan procedure because of high pulmonary vascular resistance and inadequate size of pulmonary artery. In this procedure a modified Glenn shunt without ligation of SVC may effectively reduce the volume overload on the right ventricle.

Adolescent↗

PubMed1993

[Surgical treatment of double orifice mitral valve in atrioventricular septal defect].

Ten patients with double orifice mitral valve and atrioventricular septal defect (AVSD) were examined. There were four cases with incomplete type, three with intermediate type and three with complete type AVSD. All patients with incomplete type AVSD were doing well after the mitral cleft repair, Leaving the accessory orifice untouched. Various valve repair procedures and prosthetic valve replacement were performed in the patients with intermediate and complete types of AVSD with left-sided atrioventricular valve regurgitation. There were three operative deaths, which included one patient with the intermediate type and two with the complete type. All of them were one-month old babies and were operated on emergency. Their general operative findings were hypoplasia of the common atrioventricular valve leaflets, abnormal attachment of the chorda tendineae and papillary muscle dysplasia. These findings increased the difficulty of the valve plasty to control mitral regurgitation.

Child↗

PubMed1993

[Surgical repair in hearts with univentricular atrioventricular connection and subaortic stenosis].

Between 1986 and 1990, fourteen patients with univentricular atrioventricular connection and subaortic stenosis underwent surgical treatment. The patients consisted of 7 cases of double inlet left ventricle, 4 with double inlet right ventricle, 3 with tricuspid atresia. The palliative operation was performed in 6 infants ranging in age from 17 days to 6 months. Four patients with mild subaortic stenosis underwent pulmonary artery banding, in two patients this was combined with repair of coarctation of the aorta. Two patients with severe subaortic stenosis underwent the Norwood operation. There were no operative deaths. One of two patients who underwent the Fontan operation 2 years after the Norwood operation died later. The definitive operation was performed in 8 children ranging in age from 4 to 11 years. Five of these 8 patients had previous pulmonary artery banding. Five children with double inlet left ventricle underwent septation combined with enlargement of bulboventricular foramen. Postoperatively all remained in sinus rhythm and had no pressure gradient between Aorta and left ventricle. A Fontan operation combined with a Damus operation was performed in 2 children, 1 of double inlet right ventricle and 1 of tricuspid atresia. In both cases, postoperative angiogram showed no pulmonary incompetence. One patient underwent enlargement of bulboventricular foramen after a Fontan operation. All survived later. Young infants and neonates with severe subaortic stenosis can survive by the Norwood operation. Infants with mild subaortic stenosis, although can survive by pulmonary artery banding, should be closely followed for the development of subaortic stenosis. For relief of subaortic stenosis, enlargement of bulboventricular foramen may be effective in septation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Coarctation↗

PubMed1993

[Definitive repair for double inlet ventricle and common atrio-ventricular valve].

From 1982 through 1990, 13 patients with double inlet ventricle and common atrio-ventricular valve underwent definitive cardiac surgery. Nine patients simultaneously had anomalous systemic venous connection and 4 had anomalous pulmonary venous connection. One patient with double inlet left ventricle underwent a successful partition of ventricle and atrio-ventricular valve. All other 12 patients underwent a Fontan operation, which utilized different techniques to deal with various forms of anomalous systemic and pulmonary venous connection. Four patients with common atrioventricular valve regurgitation underwent a Fontan operation combined with a concomitant circular annuloplasty of atrio-ventricular valve. In all 4 patients, the degree of regurgitation decreased postoperatively. There was one operative death (mortality 7.7%). Most of patients with double inlet ventricle and common atrio-ventricular valve now are considered to be suitable not for partition but for the Fontan operation. Because of the complexity of anatomic variables, however, the repair of anomalous systemic or pulmonary venous connections in conjunction with the Fontan operation requires an individualised plan in each patient to provide unobstructed systemic and pulmonary venous pathways. We think that a circular annuloplasty could effectively decrease the degree of atrio-ventricular valve regurgitation in most cases.

Adolescent↗

PubMed1992

Konno procedure for congenital aortic stenosis with a single coronary artery from the left coronary sinus.

A right coronary artery originating from the left coronary sinus and traversing anteriorly is thought to be one of the contraindications for a Konno aortoventriculoplasty in congenital aortic stenosis because this procedure necessitates incision of the right ventricular outflow tract. The case of a 5-year-old girl with congenital aortic stenosis associated with a single coronary artery, successfully treated surgically by the Konno procedure and right coronary artery reimplantation, is reported. Preoperatively there was a pressure gradient between the left ventricle and the ascending aorta of 109 mmHg, which disappeared postoperatively. A postoperative angiography showed a patent right coronary artery.

Abnormalities, Multiple↗

PubMed1992

[Two-stage Jatene procedure after Mustard or Senning operation].

We have successfully performed a two-stage Jatene procedure in four patients who showed severe anatomical right ventricular dysfunction after atrial switch (Mustard or Senning) operation for transposition of the great arteries. All four patients developed an adequate left ventricular pressure for the arterial switch operation by one or two-stage pulmonary artery banding. Left ventricular posterior wall thickness increased sufficiently enough after the banding although left ventricular ejection fraction showed significant decrease. After Jatene procedure left ventricular ejection fraction recovered, and RV end-diastolic volume which had been prominently enlarged preoperatively was dramatically normalized. Cardiac index increased from 3.6 +/- 1.6 l/min/m2 preoperatively to 5.3 +/- 6.1 l/min/m2 postoperatively with the decrease in left atrial pressure. Postoperative electrophysiological study revealed the recovery of sinus node function and atrial conduction by means of the take-down of atrial switch operation previously performed. We conclude that the Jatene procedure should be an ideal alternative in patients with right ventricular dysfunction after atrial switch operation. The left ventricle could be prepared by an effective pulmonary artery banding in most instances.

Cardiac Surgical Procedures↗

PubMed1992

[Surgical treatment of total anomalous pulmonary venous connection Darling type Ib using pedicled right atrial flap].

A one-month-old baby with total anomalous pulmonary venous connection (TAPVC) type Ib underwent a total correction with a pedicled right atrial (RA) flap, which was made by incising the RA wall in a quadrangular configuration. The common pulmonary vein (PV) was cut back into the left atrium (LA). Then the RA flap was sutured along the limbus of PV recess and atrial septal defect (ASD) to create a new pulmonary venous channel. The defect in the RA wall was directly closed without any prosthetic patch. Absorbable sutures (# 6-0 PDS) were used throughout. Postoperative course was uneventful and echocardiogram showed widely opened PV channel draining into the LA. We think that this procedure could be applied in various types of total and partial anomalous pulmonary venous connection, avoiding pulmonary venous obstruction on the assumption that the RA flap should grow.

Heart Atria↗

PubMed1992

Evidence for the role of neutrophils in reperfusion injury after cold cardioplegic ischemia in neonatal lambs.

The role of neutrophils in reperfusion injury after hypothermic, cardioplegia-protected ischemia is incompletely understood but may involve neutrophil-endothelial interactions. We examined 33 isolated blood-perfused neonatal lamb hearts arrested for 2 hours with 15 degrees C potassium cardioplegic solution and reperfused with unmodified blood (group C, n = 9), with neutrophil-depleted (Sepacell filter) blood (group ND, n = 9), with the addition of CV-3988, a platelet-activating factor antagonist, to the perfusate (group NA, n = 9), and with neutrophil-depleted blood plus CV-3988 (group ND/NA, n = 6). The percent recovery of isovolumic left ventricular developed pressure at a fixed balloon volume at 30 minutes after reperfusion in groups ND (84.8% +/- 11.8%, mean +/- standard deviation), NA (89.9% +/- 11.5%), and ND/NA (87.8% +/- 6.4%) were higher than in group C (73.1% +/- 7.9%) (p less than 0.05). Groups NA (105.5% +/- 13.7%) and ND/NA (108.0% +/- 11.2%) achieved higher percent recovery of coronary blood flow than group C (84.4% +/- 10.4%) (p less than 0.05). In each heart, we also tested coronary vascular resistance response to infusion of acetylcholine 10(-6) mol/L to assess endothelial function. Percent recovery of coronary vascular resistance response to acetylcholine was higher in groups ND (56.8% +/- 31.4%), NA (56.3% +/- 17.3%), and ND/NA (58.7% +/- 24.8%) than in group C (13.3% +/- 38.3%) (p less than 0.05). These results show that, after ischemia/reperfusion, groups ND, NA, and ND/NA had better recovery of both mechanical and endothelial function than group C. The parallel changes in recovery of mechanical and endothelial function suggest that neutrophil-endothelial interactions may be a significant factor in reperfusion injury.

Acetylcholine↗

PubMed1992

Growth of composite conduits utilizing longitudinal arterial autograft in growing lambs.

We examined the growth potential of a longitudinal strip of autologous aortic wall incorporated in an autologous pericardial conduit in 10 lambs (mean age 26 days, mean weight 10.1 kg). A 15 mm length of descending thoracic aorta (diameter 11.5 +/- 7 mm) was excised and replaced with a composite autograft conduit of autologous pericardium with a longitudinally inserted aortic strip 5 mm in width taken from the excised aortic tissue. Radiopaque markers along all suture lines allowed determination of growth of the aortic strip relative to growth of the composite conduit and descending aorta, in addition to growth assessment by pathologic analysis. Plain x-ray films and aortograms were performed at 7 days (baseline) and at 3, 6, 9, and 12 months. No graft became stenotic or aneurysmal. The diameter of the descending aorta distal to the conduit increased from 11.7 +/- 1.3 mm to 18.7 +/- 2.1 mm. Appropriate growth of the autograft conduit was demonstrated by a minimal change in the diameter ratio of conduit to distal aorta from 1.00 to 1.02 during a period of 12 months. The aortic strip increased to 172% +/- 19%, 148% +/- 15%, and 256% +/- 31% of baseline width, length, and area, respectively (p less than 0.05). Histologic study confirmed the maintenance of normal architecture in the aortic strip and colonization of the pericardial tissue by aortic intimal and medial elements. A clinical implant with an autologous aortic strip in an aortic homograft in a 4-year-old child with tetralogy and pulmonary atresia has also grown, according to angiography, from 15 to 21 mm in diameter at 1 year's follow-up. This study confirms that the incorporation of a free autologous arterial patch graft as part of cardiovascular reconstructive procedures permits growth.

Animals↗

PubMed1991

[Fontan type procedure in patient with borderline hemodynamics: using a temporary R-L shunt in early postoperative period].

Fontan type procedure was successfully performed to a 14-year-old patient with borderline hemodynamics using a temporary R-L shunt in early post operative period. Preoperative diagnosis was DORV (ILD), small RV, PS, ASD, juxtaposition of atrial appendages and post bilateral B-T shunts. Preoperative catheterization studies showed low PARI but insufficient pulmonary arterial size (PA-index 220). In the Fontan procedure, RA was partitioned obliquely with a composite patch of xenograft and Dacron velour. A 5.5 mm hole was created only in xenograft to allow a temporary R-L shunt. During rewarming period, systemic pressure hovering around 60 mmHg with 10 micrograms/kg/min of dopamine and dobutamine. Then a R-L shunt was created by a side to side anastomosis between the appendages with the orifice diameter of 10 mm, followed by a rise in the systemic pressure up to about 80 mmHg. One post operative day, a readjustable occluder was applied at the site of appendage anastomosis to control R-L shunt flow. According as CVP decreased, the occluder was tightened up step by step. Finally, the occluder was fully tightened up in 10 post operative days. This experience suggests that a temporary R-L shunt in early post operative period may be applicable in patient with borderline hemodynamics for Fontan type procedure.

Adolescent↗

PubMed1991

Influence of initial reperfusion pressure after hypothermic cardioplegic ischemia on endothelial modulation of coronary tone in neonatal lambs. Impaired coronary vasodilator response to acetylcholine.

To examine the effect of initial coronary reperfusion pressure on endothelial function, we subjected 16 isolated perfused neonatal lamb hearts to 2 hours of ischemia with potassium cardioplegic solution followed by reperfusion for 1 hour. Before ischemia both acetylcholine, an endothelium-dependent vasodilator, and nitroglycerin, and endothelium-independent vasodilator, caused coronary vasodilation. After ischemia the response to acetylcholine was impaired in the eight hearts with high initial reperfusion pressure (60 mm Hg) but was intact in the eight hearts with low initial reperfusion pressure (20 mm Hg for 10 minutes, 40 mm Hg for 10 minutes, and then 60 mm Hg thereafter). The response to nitroglycerin, however, remained intact regardless of initial reperfusion pressure. Recovery of resting coronary flow and myocardial oxygen consumption was lower in the group with high pressure reperfusion than in the group with low pressure reperfusion. On reperfusion a transient burst of coronary flow was exhibited by the hearts reperfused at high pressure. These results suggest that high initial reperfusion pressure impairs the endothelial modulation of coronary tone; this may be related to the effects on the coronary vasculature of the "burst" of coronary flow associated with high intravascular pressure.

Acetylcholine↗

PubMed1991

Influence of time from donor death to graft harvest on conduit function of cryopreserved aortic allografts in lambs.

We examined the influence of time from donor death to graft harvest on conduit function of aortic allografts in the thoracic aortic position in 18 lambs (mean weight, 11.4 kg). Five grafts were harvested immediately after donor death (fresh), seven at 24 hours, and six at 48 hours following cadaver storage at 4 degrees C. All grafts were treated with antibiotics and were stored by cryopreservation. All animals were catheterized postoperatively and at 3, 6, 9, and 12 months. One animal in the 24-hour group developed an allograft aneurysm, and another one died from a ruptured allograft; one graft in the fresh group occluded by nine months. No animal, however, in the 48-hour group either developed an aneurysm or occluded. There was in fact minimal change in graft diameter over time (p greater than 0.05), while the native aorta grew appropriately (greater than 50%, p less than 0.01). Forty-eight hour delay from donor death to graft harvest did not have significant effect on conduit function. This information may expand the donor pool for allografts.

Animals↗