Late myocardial revascularization in patients with tetralogy of Fallot

Since surgical correction of congenital heart diseases began in the early 1950s, a growing number of patients are reaching older age and becoming a risk for developing coronary artery disease. This study presents the clinical experience of myocardial revascularization in 4 symptomatic coronary artery disease patients with unrepaired or corrected tetralogy of Fallot. Three patients had surgery and 1 patient had percutaneous angioplasty. One corrected tetralogy of Fallot patient developed symptomatic coronary artery disease and responded favorably to medical therapy.     

Changes of antioxidant enzyme activities during cardiopulmonary bypass.

BACKGROUND: Reperfusion of ischemic heart causes the generation of free radicals, and these radicals play an important role in post-ischemic tissue damage. These free radicals are removed by scavenger enzymes and antioxidants in the cell. In this study, erythrocyte catalase, glutathione peroxidase and glutathione reductase enzyme activities were determined in patients undergoing cardiopulmonary bypass. METHODS: Experimental design: Blood samples were obtained from the coronary sinus of patients at the following times: 1) Before cardiopulmonary bypass, 2) Immediately after cardiopulmonary bypass, 3) Fifteen minutes after the second specimen, 4) Thirty minutes after the second specimen. PATIENTS: this study was carried out on eleven patients undergoing open heart operation. MEASURES: catalase, glutathione peroxidase and glutathione reductase enzyme activities were determined in these patients. RESULTS. Catalase activity was significantly decreased in the third and fourth groups as compared with the first group, which was also the control group (p<0.05). Glutathione reductase activity in the third group was significantly higher as compared with control group (p<0.001). However, there were no differences in glutathione peroxidase activity among control group and other three groups (p>0.05). CONCLUSIONS: Our results indicate that the activities of antioxidant enzyme activities in erythrocytes are changed during the ischemia and reperfusion of the heart.     

Comparison of the characteristics of myocardial function and metabolism in patients with tetralogy of Fallot

The authors studied the results of examination of the myocardium in patients with Fallot's tetralogy by means of two methods during radical correction of the congenital anomaly: invasive intraoperative myocardiography and appraisal of myocardial metabolism. High probability of the detection of dysfunction of the myocardium and disorders of of oxygen-dependent metabolic processes in it were revealed. A conclusion is drawn on the expediency of using invasive intraoperative myocardiography as a method of functional diagnosis in surgery of congenital heart diseases for appraising the condition of the myocardium.     

Coronary artery anomalies in patients with tetralogy of Fallot.

A left anterior descending coronary artery arising from the right coronary artery can be easily injured during performance of a right ventriculotomy for correction of tetralogy of Fallot. This occurred in 2 of the 23 patients in this series, and both patients died from myocardial failure in the early period after operation. Of 19 patients who presented a combination of tetralogy of Fallot and unusual coronary artery distribution, injury to the abnormal coronary artery was avoided by a transverse right ventriculotomy either alone or combined with an upper vertical incision in 17 patients. In 2 patients a Dacron tube graft was inserted between the right ventricular outflow tract and the pulmonary artery. In 2 patients a right ventriculotomy was avoided by closing the ventricular septal defect through a transaortic approach. All 21 patients survived. Before a vertical or longitudinal incision in the right ventricular outflow tract is performed, the coronary artery distribution should always be checked and confirmation made of the normal origin of the left anterior descending branch from the left coronary artery to the left of the pulmonary artery.     

Effect of aorta-coronary bypass operation on factors precipitating angina.

About two thirds (65 percent) of 271 male patients and one half of the 44 female patients who had angina pectoris prior to the aorta-coronary bypass operation experienced total relief of symptoms 1 year after the operation. This was especially apparent for angina associated with walking activity and the postprandial angina. In the nonoperated patients who had angina pectoris and only mild or no coronary artery obstruction, 38 percent of the 127 men and 27 percent of the 73 women were free of symptoms 1 year after the original examination.     

Intraoperative anoxic spells in patients with tetralogy of Fallot

We experienced 5 cases of intraoperative anoxic spell in 48 patients with tetralogy of Fallot (TOF). One of 5 cases had tetralogy with pulmonary atresia (Type A), and the others had tetralogy alone (Type D). The patient of type A who had anoxic spells during preoperative period had been on chronic propranolol therapy. However, the patients of type D had no anoxic spells during preoperative period and one in this type had not been on beta-adrenergic blocking drugs preoperatively. One patient was anesthetized with fentanyl-diazepam-O2, and the others were anesthetized with morphine-diazepam-O2. We used mainly alpha-adrenergic drugs and sodium bicarbonate for the therapy of intraoperative anoxic spells. Concerning the intraoperative anoxic spell, we have to be aware in the management of the patients with TOF, whether the patient had anoxic spells during preoperative period or not.     

Detection, prediction, and significance of perioperative myocardial infarction following aorta-coronary bypass.

One hundred consecutive patients undergoing aorta-coronary bypass grafting (ACBG) alone, without ventricular venting, were prospectively studied to determine the incidence and consequence of perioperative myocardial infarction (PMI) and the clinical variables that were predictive of PMI. Incidence was determined by serial electrocardiography (ECG) 100 patients; serum CK, GOT, and LDH (100 patients). CK isoenzymes (qualitative 100 patients, quantitated 50 patients); vectorcardiography (VCG) (78 patients); and 99mtechnetium pyrophosphate scintigraphy (TcPyp) (52 patients). The incidence of PMI by ECG was 9%; an additional 8% of cases was diagnosed by enzymes alone. The incidence of diagnostic change by VCG was 19% and by scintigraphy, 25%. Using at least one changed variable of the remaining three as the reference standard, the relative sensitivity and relative specificity of given variables in the diagnosis of PMI were as follows: ECG 67% and 100%, respectively; VCG 85% and 94%; scintigraphy 92% and 97%; and serum enzymes 86% and 96%. By univariate analysis, unstable angina was the only significant predictor of PMI. The operative mortality rate was 2% and the mortality rate at 12 months was 5%. There was a significantly greater mortality rate in patients with PMI diagnosed by ECG (p less than 0.01), in patients with unstable angina pectoris before operation (p less than 0.05), and in women (p less than 0.05).     

Effect of repair strategy on hospital cost for infants with tetralogy of Fallot.

OBJECTIVE: This study compares the total hospital cost (HC) for one-stage versus "two-stage" repair of tetralogy of Fallot (TOF) in infants younger than 1 year of age. SUMMARY BACKGROUND DATA: Total (one-stage) correction of TOF is now being performed with excellent results in infancy. Alternatively, a two-stage approach, with palliation of infants in the first year of life, followed by complete repair at a later time can be used. In some institutions, the two-stage approach is standard practice for infants younger than 1 year of age or is used selectively in patients with an anomalous coronary artery across the right ventricular outflow tract (RVOT), "small pulmonary arteries," multiple congenital anomalies, critical illnesses (CI), which increase the risk of bypass (e.g., sepsis or DIC), or severe hypercyanotic spells (HS) at the time of presentation. The cost implications of these two approaches are unknown. METHODS: The authors reviewed 22 patients younger than 1 year of age who underwent repair of TOF at their institution between 1993 and 1995. Eighteen patients had one-stage (1 degree) repair (mean age, 3.4 +/- 3.1 months; range, 3 days-9 months) and 4 patients were treated by a staged approach with initial palliation (1.6 +/- 0.4 month; range, 1.5-2 months) followed by later repair (14.75 +/- 1.5 months; range, 13-16 months). The reasons for palliation were severe HS at time of presentation (two patients), anomalous coronary artery (one patient) and CI (one patient). In the 18 patients undergoing 1 degree repair, 3 (16.6%) presented with HS, 6 (33.3%) had a transanular repair, and 6 (33.3%) were able to be repaired through an entirely transatrial approach (youngest patient, 1.5 months). The HC (1996 dollars) and hospital length of stay (LOS; days) were evaluated for all patients. The HCs were calculated using transition I, which is a cost accounting system used by our medical center since July 1992. Transition I provides complete data on all direct and indirect hospital-based, nonprofessional costs. RESULTS: There was no mortality in either group. The group undergoing 1 degree repair had an average LOS of 14.5 +/- 11.2 days compared to an average LOS for palliation of 14 +/- 6.4 days. When the palliated group returned for complete repair, the average LOS was 28.8 +/- 25 days, yielding a total LOS for the two-stage strategy of 43 +/- 30.8 days (p = 0.003 compared to 1 degree repair). The HC for 1 degree repair was $32,541 +/- $15,968 compared to $25,737 +/- $1900 for palliation (p = not significant compared to 1 degree repair) and $54,058 +/- $39,395 for subsequent complete repair (p = not significant compared to 1 degree repair) (total two-stage repair HC = $79,795 +/- $40,625; p = 0.001 compared to 1 degree repair). The LOS and HC for the two-stage group combine a total of palliation plus later repair and, as such, reflect two separate hospitalizations and convalescent periods. To eliminate cost outliers, a best-case analysis was performed by eliminating 50% of patients from each group. Using this analysis, the two-stage approach resulted in an average (total) LOS of 16.5 +/- 2.1 days compared to 8.5 +/- 1.4 days for the 1 degree group. Total cost for the two-stage strategy in this best-case group was $44,660 +/- $3645 compared to $22,360 +/- $3331 for 1 degree repair (p = 0.00001). CONCLUSIONS: The data from this review show that palliation alone generates HC similar to that from 1 degree infant repair of TOF, and total combined HC and LOS for palliation plus eventual repair of TOF (two-stage approach) are significantly higher than from 1 degree repair. Furthermore, these data do not include additional costs for care delivered between palliation and repair (e.g., outpatient visits, cardiac catheterization, serial echocardiography). Although there may be occasions when a strategy using initial palliation followed by later repair may seem prudent, the cost is clearly higher and use of health care resources greater.     

Surgical outcomes in the treatment of patients with tetralogy of Fallot and absent pulmonary valve.

OBJECTIVE: Tetralogy of Fallot and absent pulmonary valve (TOF/APV) is associated with significant pulmonary artery dilatation and airway compression. Treatment of infants presenting with respiratory symptoms early in life is associated with high mortality (20-60%). We aim to report our results and identify factors associated with survival and prolonged ventilation. METHODS: We performed a retrospective review of 62 consecutive patients following repair of TOF/APV (1982-2006). Median age at repair was 1.4 years (1 day-35 years). Twenty patients required preoperative intubation. RESULTS: Sixty-one patients underwent complete repair. Thirty-three patients underwent pulmonary artery plication (n=15) or reduction (n=18). The right ventricular outflow tract (RVOT) was reconstructed with valved conduit (n=31), bioprosthetic valve (n=18), monocusp (n=8), or transannular patch (n=4). There were three perioperative and five late deaths. All perioperative deaths were in neonates and before 1995. Five- and ten-year survival was 93+/-4% and 87+/-5%. Mean ventilatory requirements for neonates, infants, and children > or =1 year were 36+/-35, 8+/-8, and 2.6+/-2.4 days (p<0.0001). On multivariable analysis, significant factors associated with prolonged ventilation were neonates (p<0.0001) and preoperative mechanical ventilation (p=0.088). Eight airway reinterventions were needed in seven infants with persistent postoperative airway compromise, pulmonary artery suspension (n=4), innominate artery suspension (n=2), and lobectomy (n=2). Freedom from RVOT reoperation was 89+/-5% and 59+/-9% at 5 and 10 years. There were no significant risk factors for time-related survival or RVOT reoperation on multivariable analysis. CONCLUSIONS: In contrast to children and adults with TOF/APV, neonates and small infants presenting with respiratory symptoms require prolonged ventilation and additional reinterventions for airway compression. Our current surgical approach which includes reduction and suspension of pulmonary arteries, reconstruction of a competent RVOT, and aggressive postoperative ventilatory management to relieve airway obstruction offers satisfactory outcomes.     

Effect of arterial carbon dioxide tension on regional myocardial tissue oxygen tension in the dog]

We investigated the effects of arterial carbon dioxide tension on the myocardial tissue oxygen tensions of subepicardium and subendocardium in the anesthetized dogs. The study was done in fourteen open-chest mongrel dogs, weighing 13 +/- 1 kg, anesthetized with sodium pentobarbital (30 mg.kg-1 iv), and mechanically ventilated with 100% oxygen to maintain normocapnia. End tidal CO2 fraction (FECO2) was monitored continuously by capnograph. Regional myocardial tissue PO2 was measured using a monopolar polarographic needle electrode. Two pairs of combined needle sensors were carefully inserted, one in the epicardial and the other in the endocardial layer of the beating heart. Electromagnetic blood flow probe was applied on the left anterior descending artery (LAD). After a stable normocapnic ventilation, hypocapnia was induced by increasing the respiratory rate, and this mechanical hyperventilation was kept fixed throughout the experiments. To induce hypercapnia, exogenous carbon dioxide was added to the inspired gas step-wise until FECO2 reached 10%. Hypocapnic hyperventilation (PaCO2: 22 mmHg) invariably resulted in a significant reduction of coronary blood flow (LADBF) and left ventricular myocardial tissue PO2 in both epicardial and endocardial layers, while addition of carbon dioxide to the inspired gas (hypercapnic hyperventilation) reversed the change by increased LADBF and arterial PaCO2 in a dose-dependent manner. These results indicate that injudicious and severe hypocapnic hyperventilation may induce impaired myocardial tissue perfusion and oxygenation although normal cardiac output and arterial blood oxygenation are maintained.     

Pulmonary vascular disease in shunted and nonshunted patients with tetralogy of Fallot

Histometric analysis of pulmonary vascular disease was performed in 21 nonshunted patients and in 13 shunted patients with tetralogy of Fallot and in 29 normal controls. There was no significant difference in the medial thickness of the small pulmonary arteries between cases of tetralogy of Fallot and normal controls. However, the media in the shunted cases of tetralogy of Fallot gave the impression of being thicker than these in the nonshunted cases. Intimal fibrosis, regarded as organized thrombi, and thrombi of small pulmonary arteries were observed generally after 4 years of age in shunted and nonshunted cases of tetralogy of Fallot. Intimal proliferation of musculoelastosis which was formed longitudinal smooth muscle bundles and elastic fibers was characteristic in shunted patients, especially after the central palliation procedure, Waterston anastomosis and modified Blalock-Taussig (B-T) anastomosis using a Gore-Tex tube graft. However, musculoelastosis was not usually seen in the B-T anastomosis cases. Unexpected pulmonary hypertension due to shunt operation is thought to be the cause of musculoelastosis, because musculoelastosis was observed even in a patient with pulmonary hypertension 3 weeks following surgery. We, therefore, recommend original B-T anastomosis as the shunt procedure. When considering use of the other shunt operations which entail pressure load on the pulmonary vascular bed, attention must be given to the size of the anastomosis or artificial tube graft.     

Effect of acute changes in oxygen tension on flow-mediated dilation. Relation to cardiovascular risk

Objective. Oxygen-dependent changes in vascular diameters may be detrimental when the endothelium is dysfunctional. Design. Endothelial responsiveness was evaluated by brachial ultrasound and flow-mediated/nitroglycerin-mediated dilation (FMD/NMD). FMD/NMD was investigated in males with increased risk of cardiovascular disease (mean age 44±2 years, n =10) and matched controls without risk factors (44±2 years, n =10). FMD/NMD was assessed during normoxia (21% O₂, 79% N₂), while inhaling hypoxic gas (12.5% O₂, FMD_Hyp/NMD), and 100% O₂ supplementation (FMD_O2/NMD). In a second study we addressed the effect of lipid lowering. Twenty persons with cardiovascular risk (mean age 50±2 years) were treated with atorvastatin (80 mg/day) and FMD/NMD was measured during normoxia, hypoxia and oxygen supplementation before, after 1 day and 3 months. Results. Oxygen supplementation evoked vasoconstriction, while FMD_Hyp/NMD was reduced compared to FMD/NMD. Atorvastatin significantly lowered total cholesterol, LDL cholesterol, and ADMA after 1 day of treatment, while triglycerides, ApoB and hsCRP were lowered after 3 months. Atorvastatin did not change FMD/NMD irrespective of oxygen tension. Conclusion. Irrespective of risk factors or atorvastatin, hypoxia reduced endothelial vasodilation while oxygen supplementation evoked vasoconstriction.     

小儿重症法洛四联症二期根治术

目的　临床评价小儿重症法洛四联症二期根治术手术疗效。方法　1987年3月至1998年2月51例重症法洛四联症病儿,年龄2.1～13.9岁,平均(5.1±1.9)岁;体重11.1～28.0kg,平均(14.2±3.8)kg。姑息术与二期根治术时间间隔3～22个月。结果　1例远端肺血管发育差者,术后心衰死亡。手术成功率98%,术后随访满意。结论　二期根治术能提高重症法洛四联症病儿术后生存率。