Francisco J. Puga

Late follow-up of 1095 patients undergoing operation for complex congenital heart disease utilizing pulmonary ventricle to pulmonary artery conduits

BACKGROUND Pulmonary ventricle (PV) to pulmonary artery (PA) conduits have made possible the correction of many complex congenital cardiac anomalies. METHODS Between April 1964 and January 2001, 1270 patients underwent operation with conduit placement from the PV to PA. The present study evaluates late outcome of 1095 patients (612 males, 483 females) having an operation before July 1992. Mean age was 9.6 +/- 8.2 years old. Diagnoses included pulmonary atresia/tetralogy of Fallot (459), transposition of the great arteries (TGA) (232), truncus arteriosus (193), double outlet right ventricle (DORV) (121), corrected TGA (49), septated univentricular heart (36), and other (5). A porcine-valved Dacron conduit was used in 730, homograft in 239, and non-valved conduit in 126. RESULTS Early mortality decreased from 23.5% prior to 1980 to 3.7% for the most recent decade. Mean follow-up was 10.9 years (maximum, 29 years). Actuarial survival for early survivors at 10 and 20 years was 77.0% +/- 1.5% and 59.5% +/- 2.6%. On univariate analysis, clinical and hemodynamic factors associated with late mortality were male gender, older age at operation, higher post-repair PV/systemic ventricle (SV) pressure ratio, higher distal PA pressure, and longer bypass time (p < or = 0.01 for all). On multivariate analysis, independent risk factors for late mortality were male gender, older age at operation, diagnosis of TGA, corrected TGA, truncus, or univentricular heart, and PV/SV pressure ratio > or = 0.72 (p < or = 0.03 for all). Freedom from reoperation for conduit failure at 10 and 20 years was 55.5% +/- 2.0% and 31.9% +/- 2.7%. On multivariate analysis, independent risk factors for conduit failure were homograft conduit, diagnosis of TGA, younger age at operation, and smaller conduit size (p < or = 0.007 for all). Reoperation for one conduit replacement was performed in 306 patients, two conduit replacements in 55 patients, three in 6 patients, and four in 3 patients. Overall early mortality for conduit replacement in this series was 4.9%; it was 1.7% for patients operated on from 1989 through 1992. At follow-up, 84% of survivors were in NYHA class I or II. CONCLUSIONS Operations that include conduit placement and replacement can be performed with low early mortality. Younger age at operation was associated with improved late survival. The diagnosis of TGA was associated with increased risk for conduit failure, and the durability of the homograft, in this series, was inferior to the porcine-valved Dacron conduit. Quality of life was excellent for most patients despite the need for reoperation.

OUTCOME OF PULMONARY AND AORTIC HOMOGRAFTS FOR RIGHT VENTRICULAR OUTFLOW TRACT RECONSTRUCTION

To determine late patient outcome and homograft durability, we reviewed 326 patients who received aortic (n = 230) or pulmonary (n = 118) cryopreserved homografts for right ventricular outflow reconstruction between January 1985 and October 1993. Patient survival, including operative mortality, 5 years after the operation was similar between the two groups (pulmonary homograft 86%, aortic homograft 80%; p = not significant by log-rank test). However, 5-year freedom from homograft failure was significantly better for pulmonary homografts (94% versus 70%, p < 0.01 by log-rank test). Late calcification was evaluated by chest roentgenography and echocardiography. Overall, 20% of aortic homografts became moderately or severely calcified compared with 4% of pulmonary homografts (p < 0.01). Twenty-six percent of aortic homografts in children 4 years old or younger had moderate or severe obstruction associated with calcification, whereas only 11% of aortic homografts in patients over 4 years of age had calcific obstruction (p < 0.01). No late deaths among patients receiving pulmonary homografts were related to graft failure; two late deaths in the aortic homograft group were homograft related. Risk factors for patient mortality and homograft failure (defined as either need for homograft replacement because of homograft failure or as homograft-related death) were identified by the Cox multivariate analysis. Aortic type of homograft was a significant risk factor for homograft failure (p < 0.0001), but type of homograft was not correlated with patient mortality. Age 4 years or younger was a significant risk factor for both mortality (p < 0.01) and homograft failure (p = 0.03) in aortic homograft recipients but not in pulmonary homograft recipients. These results indicate that both aortic and pulmonary homografts provided excellent intermediate-term patient survival after right ventricular outflow tract reconstruction, but pulmonary homografts are more durable than aortic homografts with less calcification and obstruction, especially among children 4 years old or younger.

The modified fontan operation: An analysis of risk factors for early postoperative death or takedown in 702 consecutive patients from one institution

To better understand risk factors associated with early postoperative death or failure, we reviewed our entire experience with 702 consecutive patients who had the modified Fontan operation at the Mayo Clinic between October 1973 and December 1989. The event rate for takedown of repair or death during the initial hospitalization or within 30 days of the operation was 14.8% (successful takedown of the repair, n = 6; death, n = 98). To identify variables associated with early death or Fontan takedown, we analyzed 33 clinical and hemodynamic variables in a univariate and multivariate manner. On the basis of a stepwise logistic discriminant analysis, patients who were younger and operated on before 1980 with a higher preoperative pulmonary artery mean pressure, asplenia, higher intraoperative (after Fontan operation) right atrial pressure, longer aortic crossclamp time, and pulmonary artery ligation were more likely to have the outcome event of interest (p values < 0.05). A new variable, corrected pulmonary artery pressure (that is, mean preoperative pulmonary artery pressure divided by the ratio of pulmonary to systemic flow if the ratio of pulmonary to systemic flow is greater than 1.0), was significantly associated with the outcome event univariately (p = 0.002), but was no more predictive than the preoperative pulmonary artery mean pressure. Variables less predictive of the outcome event in this analysis included multiple prior operations, polysplenia syndrome, complex anatomy other than asplenia syndrome, and systemic atrioventricular valve regurgitation. These results represent the largest single-institution review of the Fontan operation and suggest that some anatomic and hemodynamic variables previously predictive of poor early outcome have been nullified by current operative methods.

Late results of systemic atrioventricular valve replacement in corrected transposition.

From December 1964 to October 1993, 40 patients (aged 5 months to 70 years, mean 21.8 years, median 13.6 years) with corrected transposition and systemic atrioventricular valve insufficiency underwent replacement (n = 39) or repair (n = 1) of the systemic atrioventricular valve. Thirty-nine patients had situs solitus and 1 had situs inversus. Associated anomalies included Ebsteins malformation of the systemic atrioventricular valve (n = 22), ventricular septal defect (n = 19), and pulmonary stenosis (n = 14). Preoperatively, 16 patients (40.0%) had complete heart block and 27 patients (67.5%) were in New York Heart Association functional classes III and IV. The early mortality was 10.0% (n = 4) and 8 patients died subsequently. The principal cause of death in all 12 patients was systemic ventricular failure. Overall survival including early mortality was 78.0% at 5 years and 60.7% at 10 years; survival excluding early mortality was 86.7% at 5 years and 67.5% at 10 years. Survivorship correlated with preoperative systemic ventricular ejection fraction of 44% or more (p < 0.001) and later interval of operation (9 deaths in 15 patients before 1981 versus 3 deaths in 25 patients subsequently) (p = 0.06). There were no cases of surgically induced complete heart block. Two patients underwent late reoperations related to the systemic atrioventricular valve prosthesis. Follow-up extended to 26.0 years (median 4.7 years). At last follow-up, 18 of the 28 survivors were in New York Heart Association functional class I, 9 were in class II, and 1 was in class III. We conclude that the results of systemic atrioventricular valve replacement in corrected transposition have improved significantly during the past decade. To preserve systemic ventricular function, we suggest operation be considered at the earliest sign of progressive ventricular dysfunction as assessed by serial clinical evaluation and echocardiography.

Normal Myocardial Function and Energetics in Volume-Overload Hypertrophy in the Cat

Depressed contractility with a paradoxically increased myocardial oxygen consumption has been associated with pressure-overload hypertrophy. The present experiments investigated myocardial hypertrophy induced by volume overload. Right ventricular volume overload was produced in 19 cats by surgically creating atrial septal defects (ASD); these cats were compared with 10 sham-operated control cats. The ASD cats showed an increase in the ratio of pulmonary blood flow to systemic blood flow from 1.04 ± 0.01 (SE) (control) to 3.30 ± 0.28 (ASD) (P < 0.001). Hypertrophy was evidenced by a ratio of right ventricular weight to body weight of 0.59 ± 0.03 g/kg for control cats and 0.97 ± 0.03 for ASD cats (P < 0.001). A polarographic muscle bath was used to study papillary muscles from 8 control and 8 ASD cats. ASD muscles demonstrated normal force-velocity curves, with maximal measured preload velocities of 1.32 ± 0.05 muscle lengths/sec: control velocities were 1.33 ± 0.05 muscle lengths/sec (P > 0.9). The myocardial oxygen consumption of isotonic contractions was normal for ASD muscles. The length-tension curves were comparable, with developed tensions at Lmax of 6.20 ± 0.31 g/mm2 for ASD muscles and 6.34 ± 0.23 g/mm2 for control muscles (P > 0.7). Myocardial oxygen consumption pergram of tension development at Lmax was 0.66 ± 0.06 μliters/mg beat−1 × 10−3 in the ASD muscles and 0.65 ± 0.05 μliters/mg beat−1 × 10−3 in the control muscles (P > 0.8). The mitochondrial oxidative indexes from control and hypertrophied right ventricles were similar, with respiratory control indexes of 14.3 ± 0.8 for ASD hearts and 12.8 ± 1.6 for control hearts (P > 0.1). These data demonstrate that contractility and energetics are normal in volume-overload hypertrophy, although these same factors are abnormal in pressure-overload hypertrophy. Thus, hypertrophy alone is not a common denominator for abnormal myocardial function and energetics.

Surgical resection of ventricular cardiac fibromas: early and late results.

BACKGROUND Cardiac fibromas are rare tumors. Indications for and preferred type of operation are controversial, and little is known about early and late results of operation. METHODS We retrospectively reviewed records of 18 patients who underwent resection of ventricular cardiac fibromas from 1964 to October 2002. Follow-up was obtained from current medical records and recent telephone and written correspondence. RESULTS Seventeen patients had complete resection and 1 had subtotal resection of one or more fibromas. Tumors were located in the left ventricle (n = 12), septum (n = 4), or right ventricle (n = 2). A 2-month-old infant died intraoperatively. None of the surviving 17 patients had complete heart block. Follow-up lasted up to 33.7 years for a total of 172.1 patient-years. There were no late deaths. Fourteen patients were asymptomatic, 1 was in New York Heart Association functional class II, and 2 were in class III. There was no recurrence of tumor after complete resection and no change in size of residual tumor in the 1 patient who underwent subtotal resection. CONCLUSIONS Although cardiac transplantation has been suggested by some as a preferable operation, most ventricular fibromas, even though extensive, can be completely resected with excellent early and late results. For patients with tumors extending into critical locations, subtotal excision can also give excellent late survival.

Influence of ventricular morphology on outcome after the Fontan procedure

The modified Fontan procedure has gained wide acceptance in the treatment of various congenital heart defects. Determination of risk factors for mortality remains an important issue for optimizing patient selection for the Fontan procedure. Conflicting results have been reported about whether ventricular morphology is a risk factor in these patients. Survival free of Fontan takedown or cardiac transplantation was assessed in the first 500 patients undergoing the Fontan procedure at our institution. This survival was correlated with ventricular morphology as evaluated by angiography. Both multivariate and univariate analyses indicated ventricular morphology was predictive of early survival free of Fontan takedown or cardiac transplantation following the procedure. However, there was no statistical evidence for ventricular morphology being a risk factor for mortality in patients alive 6 months after the procedure. Ventricular morphology is a risk factor for early survival in patients undergoing a Fontan procedure, with left ventricular morphology associated with a better early survival than right ventricular morphology.

Surgical repair of univentricular heart (double inlet left ventricle) with obstructed anterior subaortic outlet chamber

The results of operation in all patients with univentricular heart and an obstructed anterior subaortic outlet chamber who were operated on utilizing extracorporeal circulation at the Mayo Clinic from 1973 through 1983 were reviewed. Ten of the 18 patients died during the immediate postoperative period and there was one late death. Factors significantly related to operative and immediate postoperative mortality were age at operation, cardiothoracic ratio on X-ray examination, degree of ST depression on electrocardiogram and pressure gradient across the outlet foramen at catheterization. Autopsy in eight cases revealed significant hypertrophy of ventricular myocardium and a small outlet foramen that was considered stenotic relative to either body surface area or aortic root area. The ventricular myocardium showed histologic changes of chronic ischemia that predated the surgical procedure.

Total correction of tetralogy of fallot at age 40 years and older: Long-term follow-up

Whether total surgical correction of tetralogy of Fallot in adults aged 40 years old or older has acceptable operative risk and gratifying long-term results is unknown. The Mayo Clinic experience (June 1960 to May 1982) with 30 patients 40 to 60 years old (mean 47) who had total surgical correction of tetralogy of Fallot was reviewed. Preoperatively, 4 patients (13%) were in functional class I, 9 (30%) in class II and 17 (57%) in classes III and IV. Eight patients (27%) had had preoperative complications: five had a cerebrovascular accident and three had infective endocarditis. Only 11 patients (37%) had had palliative surgery 16 to 34 years (mean 22) before total surgical correction. Total surgical correction was successful in all patients. Right ventricular to left ventricular (RV/LV) pressure ratio of 0.65 or less was achieved in 28 (93%) of the 30 patients. One patient died of ventricular fibrillation (RV/LV ratio = 0.8) 2 days postoperatively, one had complete heart block and one had a cerebrovascular accident 7 days after operation. At follow-up of 5 to 266 months (mean 110), there were seven late deaths: two sudden at 5 and 21 years, respectively, after operation, one from myocardial infarction at 11 years, one from cerebrovascular accident at 11 years, one from congestive heart failure (RV/LV ratio = 1.0) at 8 years and two from noncardiac causes. Of the 22 patients who survived, 16 are in class I, 5 are in class II and 1 is in class III.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood loss in infants and children for open heart operations: albumin 5% versus Fresh-Frozen plasma in the prime

BACKGROUND Infants and children undergoing cardiopulmonary bypass become substantially hemodiluted secondary to the volume used to prime the oxygenator. Fresh-frozen plasma has been included in the prime to lessen dilution of clotting factors and correspondingly minimize blood loss and transfusions. METHODS We prospectively randomized 56 patients weighing 10 kg or less who required cardiopulmonary bypass to receive either one unit of fresh-frozen plasma or 200 mL of albumin 5% in the prime. After protamine administration, samples for prothrombin time, fibrinogen, platelet count, and thromboelastogram were obtained. Mediastinal chest tube drainage and transfusion requirements were documented. RESULTS There were no significant differences between groups regarding demographic or surgical characteristics. Blood loss during the first 24 hours was similar in both groups, but total transfusions were significantly greater in those who received fresh-frozen plasma instead of albumin 5% in the prime (8.0 +/- 4.2 versus 6.1 +/- 4.5 U, respectively; p = 0.035). Post hoc analyses suggest that for cyanotic patients and patients undergoing complex operations, fresh-frozen plasma in the prime results in less blood loss than albumin 5%. CONCLUSIONS Substitution of albumin 5% for fresh-frozen plasma in the prime of acyanotic patients weighing 10 kg or less who undergo noncomplex operations requiring cardiopulmonary bypass significantly reduces perioperative transfusions without increasing blood loss. Further investigation is needed to determine whether increased blood loss is associated with increased transfusions when albumin 5% is substituted for fresh-frozen plasma in the prime of infants and children who are cyanotic or undergoing complex operations.