Prospective, controlled study of developmental outcome in survivors of extracorporeal membrane oxygenation: the first 24 months.

OBJECTIVE: Survivors of venoarterial extracorporeal membrane oxygenation (ECMO) are considered to be at risk for developmental disabilities, but there are few controlled outcome studies. A prospective, controlled study of outcome was performed to quantify the degree and frequency of developmental disabilities in ECMO survivors compared with a matched control group. METHODS: From May 1987 through November 1990, 40 of 47 neonates treated with ECMO survived at the University of Texas Medical Branch in Galveston. Longitudinal developmental data were collected, using the Bayley Scales of Infant Development, on 22 ECMO infants and 29 healthy term control infants at 6, 12, and 24 months. Language was assessed at 24 months using the Sequenced Inventory of Communication Development. An additional 13 ECMO infants had developmental data for at least one time point. RESULTS: Healthy term infants performed significantly better than ECMO infants on the Bayley Scales of Infant Development at 6 and 24 months and on the Sequenced Inventory of Communication Development at 24 months. Mean scores of ECMO infants were well within the average range and 77% of the ECMO infants were developmentally normal. CONCLUSIONS: These data suggest that early developmental morbidity in ECMO survivors is low, considering the severity of their neonatal illness.

Intracranial hemorrhage during extracorporeal membrane oxygenation in neonates.

Intracranial hemorrhage is a complication of extracorporeal membrane oxygenation for the treatment of neonatal respiratory failure. A retrospective review of 35 neonates treated with extracorporeal membrane oxygenation was performed; ten had intracranial hemorrhage. Infants with intracranial hemorrhage had lower birth weights and were gestationally younger than infants with intracranial hemorrhage. Eight of eight neonates of less than 35 weeks' gestational age sustained intracranial hemorrhage. Six died immediately after extracorporeal membrane oxygenation was stopped. Two lived less than 1 year. Two of 27 neonates older than 34 weeks' gestational age sustained intracranial hemorrhage. One child is normal, the other died at 18 months of age. Based on the results of this study, the risk of intracranial hemorrhage appears low in neonates of greater than 34 weeks' gestational age who undergo extracorporeal membrane oxygenation treatment for severe respiratory failure. The use of extracorporeal membrane oxygenation, as it is presently performed, is contraindicated in neonates of less than 35 weeks' gestational age because of the risk of intracranial hemorrhage.

Extracorporeal circulation in neonatal respiratory failure: a prospective randomized study.

A prospective controlled randomized study of the use of extracorporeal membrane oxygenation to treat newborns with respiratory failure was carried out using the "randomized play-the-winner" statistical method. In this method the chance of randomly assigning an infant to one treatment or the other is influenced by the outcome of treatment of each patient in the study. If one treatment is more successful, more patients are randomly assigned to that treatment. A group of 12 infants with birth weight greater than 2 kg met objective criteria for high mortality risk. One patient was randomly assigned to conventional treatment (that patient died); 11 patients were randomly chosen for extracorporeal membrane oxygenation (all survived). Intracerebral hemorrhage occurred in one of 11 surviving children. Extracorporeal membrane oxygenation allows lung rest and improves survival compared to conventional ventilator therapy in newborn infants with severe respiratory failure.

Chromosome aberrations as a predictor of clinical outcome for smoking associated lung cancer.

The ability to identify individuals at greatest risk of developing lung cancer can significantly enhance the efficacy of intervention modalities. One strategy for identifying these individuals is through biomarkers that reflect the severity of their cancer. In the present study, we evaluated 22 lung cancer patients and 35 controls to determine whether the frequency of chromosome aberrations was significantly associated with specific clinical variables such as the histological type, grade and stage of the tumors. Chromosome aberrations (expressed as total breaks) were investigated on chromosome 1 in interphase nuclei obtained from blood lymphocytes of the study participants using the fluorescence in situ hybridization (FISH) chromosome aberration assay. Our results indicate a significant linear increase (P=0.01) in the level of breaks with respect to the grade of the carcinoma. The poorly differentiated tumors had a significantly higher level of chromosome breaks mean+/-SD (1.7+/-0.46) as compared to the well differentiated tumors (0.98+/-0.23, P<0.05). These results indicate that chromosome aberrations, as determined by the FISH assay, can be used as a biomarker for identifying individuals with aggressive types of lung cancer and potentially, as a predictor for prognostic outcome of the disease.

Polymorphism of metabolizing genes and lung cancer histology: prevalence of CYP2E1 in adenocarcinoma.

The relationship between genetic predisposition and development of specific cancers has not been adequately elucidated. In this study, the involvement of three polymorphic genes (CYP2E1, GSTM1, and GSTT1) in the development of different histological types of lung cancer was investigated. DNA was extracted from peripheral blood lymphocytes of lung cancer patients who have been long-term cigarette smokers (n = 52). Allelic variants of CYP2E1 were detected using PCR followed by PstI restriction enzyme digest and RFLP analysis, which detects a specific mutation causing over-expression of the gene. GSTM1 and GSTT1 genotypes were detected using two separate differential PCR methods. Our results indicate a 13.5% allele frequency for the CYP2E1 rare PstI site among the lung cancer patients which represents a 3.4-fold increase over the normal controls (OR = 3.5, 95% CL = 0.65-25.8). A novel observation is that all the patients with this polymorphism had adenocarcinomas only, resulting in a significant association between them (OR = 16.17, 95% CL = 0.95-73, P = 0.02). The frequency of the null GSTM1 gene was 42.3% among the lung cancer patients with no preferential tendency towards developing squamous cell carcinoma versus adenocarcinoma (OR = 1.10, 95% CL = 0.3-4.14, P = 0.5). The GSTT1 gene was absent in 21.1% of the patients with a non-significant tendency towards developing squamous cell carcinoma (OR = 1.23, 95% CL = 0.25-6.1, P = 0.5). Another important observation is the significant predominance of the three predisposing polymorphic alleles among the adenocarcinoma patients (OR = 3.4, 95% CL = 0.78-16.1, P = 0.05) compared with the squamous cell carcinoma patients. The results of this study indicate that the inheritance of several polymorphic metabolizing genes, particularly the CYP2E1 gene, contributes not only to the development of lung cancer but also to the development of specific types of cancer.

Percutaneous extracorporeal arteriovenous carbon dioxide removal improves survival in respiratory distress syndrome: a prospective randomized outcomes study in adult sheep.

OBJECTIVE: Arteriovenous carbon dioxide removal (AVCO(2)R) uses a simple arteriovenous shunt for CO(2) removal to minimize barotrauma/volutrauma from mechanical ventilation. We performed a prospective randomized outcomes study of AVCO(2)R in our new, clinically relevant model of respiratory distress syndrome. METHODS: Adult sheep (n = 18) received an LD(50) severe smoke inhalation and 40% third-degree burn. When respiratory distress syndrome developed (PaO (2)/FIO (2) < 200 at 40 to 48 hours), animals were randomized to the AVCO(2)R (n = 9) or sham group (n = 9) for 7 days. Ventilator management protocols mandated reductions in minute ventilation, first tidal volume to peak inspiratory pressure less than 30 cm H(2)O, then respiratory rate when PaCO (2) was less than 40 mm Hg. PaO (2) was kept above 60 mm Hg by adjusting FIO (2). When FIO (2) was 0.21, animals were weaned. RESULTS: The study required 2946 animal-hours of critical care with 696 AVCO(2)R hours. One died in each group during model development. AVCO(2)R flow from 820 mL/min to 970 mL/min (11% to 14% cardiac output) removed CO(2) at a rate of 92 to 116 mL/min (mean 103 mL/min; 93%-97% of CO(2) production). Heart rate, mean arterial pressure, cardiac output, and pulmonary arterial wedge pressure remained relatively constant. Within 48 hours, AVCO(2)R allowed significant ventilator reductions versus baseline in the following measurements: tidal volume (420 to 270 mL), peak inspiratory pressure (25 to 14 cm H(2)O), minute ventilation (13 to 5 L/min), respiratory rate (26 to 16 breaths/min), and FIO (2) (0.88 to 0.35). Ventilator-free days with AVCO(2)R were 3.9 versus 0.2 (P <.01) for sham animals, and ventilator-dependent days with AVCO(2)R were 2.4 versus 6.2 (P <.01) for the 3 sham survivors. All 8 AVCO(2)R animals and 3 of 8 sham animals survived 7 days after randomization. CONCLUSIONS: Percutaneous AVCO(2)R achieved significant reduction in airway pressures, increased ventilator-free days, decreased ventilator-dependent days, and improved survival in a sheep model of respiratory distress syndrome.

Prolonged hemodynamic stability during arteriovenous carbon dioxide removal for severe respiratory failure.

OBJECTIVE: The effects of prolonged arteriovenous carbon dioxide removal on hemodynamics during severe respiratory failure were evaluated in adult sheep with severe smoke inhalation injury. METHODS: Adult female sheep (n = 6,33.8 +/- 5.2 kg) were subjected to intratracheal cotton severe smoke insufflation to a mean carboxyhemoglobin level of 83% +/- 3%. Twenty-four hours after injury, a low-resistance 2.5 m2 membrane oxygenator was placed in a carotid-to-jugular pumpless arteriovenous shunt at unrestricted flow to allow complete carbon dioxide removal and reductions in ventilator support. Animals remained conscious, and heart rate, cardiac output, mean arterial pressure, and pulmonary arterial pressure were measured at baseline, after injury, and daily during support with the arteriovenous carbon dioxide removal circuit for 7 days. RESULTS: All animals survived the study period. Carbon dioxide removal ranged from 99.7 +/- 13.7 to 152.2 +/- 16.2 ml/min, and five (83%) of the six animals were successfully weaned from the ventilator before day 7. During full support with the arteriovenous carbon dioxide removal circuit, shunt flow ranged from 1.24 +/- 0.06 to 1.43 +/- 0.08 L/min and accounted for 20.1% +/- 1.4% to 25.9% +/- 2.4% of cardiac output. No statistically significant changes in heart rate, cardiac output, mean arterial pressure, or pulmonary artery pressure were demonstrated over the study course despite the extracorporeal shunt flow. CONCLUSIONS: Arteriovenous carbon dioxide removal as a simplified means of extracorporeal gas exchange support is relatively safe without adverse hemodynamic effects or complications.

Pathophysiology of ovine smoke inhalation injury treated with extracorporeal membrane oxygenation.

An ovine model was used to study the pathophysiology of smoke inhalation injury treated with extracorporeal membrane oxygenation (ECMO). Smoke inhalation is characterized by leukocyte-oxygen free-radical mediated acute lung injury. Treatment with ECMO was by extracorporeal venoarterial or venovenous perfusion using a venous drainage reservoir, roller pump, heat exchanger, and membrane lung oxygenator capable of oxygen delivery to and carbon dioxide removal from a patient. Blood-foreign surface interactions are known to occur during ECMO. We examined the effects of ECMO on circulating leukocytes, oxygen free-radical activity, thromboxane release, and gas exchange after smoke inhalation injury. Animals treated with smoke and ECMO had significantly increased circulating thromboxane B2 levels and oxygen free-radical activity compared with sham-treated animals and animals treated with smoke and mechanical ventilation (MV). Likewise, there was a significant increase in lung wet-to-dry weight ratios in animals treated with smoke and ECMO compared with those treated with smoke and MV. These data may account for the initial deterioration in native lung function after the initiation of ECMO and imply that ECMO may potentiate the pathophysiology of smoke inhalation injury.

Gut mucosal ischemia during normothermic cardiopulmonary bypass results from blood flow redistribution and increased oxygen demand.

Impaired gut mucosal perfusion has been reported during cardiopulmonary bypass. To better define the adequacy of gut blood flow and oxygenation during cardiopulmonary bypass, we measured overall gut blood flow and ileal mucosal flow and their relationship to mucosal pH, mesenteric oxygen delivery and oxygen consumption in immature pigs (n = 8). Normothermic, noncross-clamped, right atrium-to-aorta cardiopulmonary bypass was maintained at 100 ml/kg per minute for 120 minutes. Animals were instrumented with an ultrasonic Doppler flow probe on the superior mesenteric artery, a mucosal laser Doppler flow probe in the ileum, and pH tonometers in the stomach, ileum, and rectum. Radioactive microspheres were injected before and at 5, 60, and 120 minutes of cardiopulmonary bypass for tissue blood flow measurements. Overall gut blood flow significantly increased during cardiopulmonary bypass as evidenced by increases in superior mesenteric arterial flow to 134.1% +/- 8.0%, 137.1% +/- 7.5%, 130.3% +/- 11.2%, and 130.2% +/- 12.7% of baseline values at 30, 60, 90, and 120 minutes of bypass, respectively. Conversely, ileal mucosal blood flow significantly decreased to 53.6% +/- 6.4%, 49.5% +/- 6.8%, 58.9% +/- 11.6%, and 47.8% +/- 10.0% of baseline values, respectively. Blood flow measured with microspheres was significantly increased to proximal portions of the gut, duodenum and jejunum, during cardiopulmonary bypass, whereas blood flow to distal portions, ileum and colon, was unchanged. Gut mucosal pH decreased progressively during cardiopulmonary bypass and paralleled the decrease in ileal mucosal blood flow. Mesenteric oxygen delivery decreased significantly from 67.0 +/- 10.0 ml/min per square meter at baseline to 42.4 +/- 4.6, 44.9 +/- 3.5, 46.0 +/- 3.6, and 42.9 +/- 3.9 ml/min per square meter at 30, 60, 90, and 120 minutes of bypass. Despite the decrease in mesenteric oxygen delivery, mesenteric oxygen consumption increased progressively from 10.8 +/- 1.4 ml/min per square meter at baseline to 13.4 +/- 1.2, 15.9 +/- 1.2, 16.7 +/- 1.4, and 16.6 +/- 1.54 ml/min per square meter, respectively. We conclude that gut mucosal ischemia during normothermic cardiopulmonary bypass results from a combination of redistribution of blood flow away from mucosa and an increased oxygen demand.

Complications of neonatal extracorporeal membrane oxygenation. Collective experience from the Extracorporeal Life Support Organization.

Since 1973, 7667 neonates have been treated with extracorporeal membrane oxygenation for severe respiratory failure and their cases reported to the Extracorporeal Life Support Organization Registry. The overall survival was 81% in these neonates, who were thought to have a survival of 20% without extracorporeal membrane oxygenation. A total of 4322 mechanical complications (0.56 +/- 0.84 per case) and 13,827 patient complications (1.80 +/- 2.12 per case) were reported overall. The most common mechanical complications included clots in the circuit (19%), cannula placement (9%), oxygenator failure (4%), and others (9%). Common patient complications included cardiopulmonary (43%), neurologic (35%), bleeding (35%), metabolic (32%), renal (25%), and renal (25%), and infectious (9%). From the initial experience to 1988 the average number of mechanical complications per case was 0.27 per case and this significantly increased during 1990 to 1992 to 0.75 per case (p < 0.05). Likewise, from 1973-1985 to 1988 the average patient complications per case were 1.44 per case and this significantly increased during 1990 to 1992 to 2.10 per case. During the same periods, patient survival significantly decreased from 84% (1973-1985 to 1988, n = 2463) to 80% (1990 to 1992, n = 4005). Venovenous double-lumen single cannula extracorporeal membrane oxygenation had a higher survival than venoarterial extracorporeal membrane oxygenation (91% versus 81%) and a lower rate of major neurologic complications. The incidence and survival with seizures (6% and 89% venovenous versus 13% and 61% venoarterial) or cerebral infarction (9% and 69% venovenous versus 14% and 46% venoarterial) was significantly lower with the venovenous method and appeared to have a substantial impact on overall survival. The correlation of patient complication rate and total complication rate with survival was highly significant, however, causality cannot be established. Explanations for the increase in complications, relative to a decrease in survival, despite a growing nationwide experience include (1) increased complexity of cases as many programs expand entry criteria (more premature infants, infants with grade 1 or 2 intracranial hemorrhage, and complex congenital diaphragmatic hernia), (2) a growing number of programs with fewer cases per program, yet greater accessibility, (3) less reluctance to report complications encountered during extracorporeal membrane oxygenation as group experience grows, and (4) changes in the Extracorporeal Life Support Organization data form to be more inclusive of more minor complications.

Total extracorporeal arteriovenous carbon dioxide removal in acute respiratory failure: a phase I clinical study.

OBJECTIVE: To evaluate the safety and efficacy of pumpless extracorporeal arteriovenous carbon dioxide removal (AVCO2R) in subjects with acute respiratory failure and hypercapnia. DESIGN: A phase I within-group time series trial in which subjects underwent up to 72 h of support with AVCO2R in intensive care units of two university hospitals. PATIENTS: Eight patients with acute hypercapnic respiratory failure or hypoxemic respiratory failure managed with permissive hypercapnia. INTERVENTIONS: Extracorporeal CO2 removal was achieved through percutaneous cannulation of the femoral artery and vein, and a simple extracorporeal circuit using a commercially available membrane gas exchange device for carbon dioxide exchange. MEASUREMENTS AND RESULTS: Measurements of hemodynamics, blood gases, ventilatory settings, and laboratory values were made before initiation of AVCO2R, and at subsequent intervals for 72 h. PaCO2 decreased significantly from 90.8+/-7.5 mmHg to 52.3+/-4.3 and 51.8+/-3.1 mmHg at 1 and 2 h, respectively. This decrease occurred despite a decrease in minute ventilation from a baseline of 6.92+/-1.64 l/min to 4.22+/-.46 and 3.00+/-.53 l/min at 1 and 2 h. There was a normalization of pH, with an increase from 7.19+/-.06 to 7.35+/-.07 and 7.37+/-.05 at 1 and 2 h. These improvements persisted during the full period of support with AVCO2R. Four subjects underwent apnea trials in which AVCO2R provided total carbon dioxide removal during apneic oxygenation, resulting in steady-state PaCO2 values from 57 to 85 mmHg. Hemodynamics were not significantly altered with the institution of AVCO2R. There were no major complications attributed to the procedure. CONCLUSION: Pumpless extracorporeal AVCO2R is capable of providing complete extracorporeal removal of carbon dioxide during acute respiratory failure, while maintaining mild to moderate hypercapnia. Applied in conjunction with mechanical ventilation and permissive hypercapnia, AVCO2R resulted in normalization of arterial PCO2 and pH and permitted significant reductions in the level of mechanical ventilation.

Analysis of factors affecting gas exchange in intravascular blood gas exchanger.

A mathematical model of an intravascular hollow-fiber gas-exchange device, called IVOX, has been developed using a Krogh cylinder-like approach with a repeating unit structure comprised of a single fiber with gas flowing through its lumen surrounded by a coaxial cylinder of blood flowing in the opposite direction. Species mass balances on O2 and CO2 result in a nonlinear coupled set of convective-diffusion parabolic partial differential equations that are solved numerically using an alternating-direction implicit finite-difference method. Computed results indicated the presence of a large resistance to gas transport on the external (blood) side of the hollow-fiber exchanger. Increasing gas flow through the device favored CO2 removal from but not O2 addition to blood. Increasing blood flow over the device favored both CO2 removal as well as O2 addition. The rate of CO2 removal increased linearly with the transmural PCO2 gradient imposed across the device. The effect of fiber crimping on blood phase mass transfer resistance was evaluated indirectly by varying species blood diffusivity. Computed results indicated that CO2 excretion by IVOX can be significantly enhanced with improved bulk mixing of vena caval blood around the IVOX fibers.

Airway mechanics, gas exchange, and blood flow in a nonlinear model of the normal human lung.

A model integrating airway/lung mechanics, pulmonary blood flow, and gas exchange for a normal human subject executing the forced vital capacity (FVC) maneuver is presented. It requires as input the intrapleural pressure measured during the maneuver. Selected model-generated output variables are compared against measured data (flow at the mouth, change in lung volume, and expired O2 and CO2 concentrations at the mouth). A nonlinear parameter-estimation algorithm is employed to vary selected sensitive model parameters to obtain reasonable least squares fits to the data. This study indicates that 1) all three components of the respiratory model are necessary to characterize the FVC maneuver; 2) changes in pulmonary blood flow rate are associated with changes in alveolar and intrapleural pressures and affect gas exchange and the time course of expired gas concentrations; and 3) a collapsible midairway segment must be included to match airflow during a forced expiration. Model simulations suggest that the resistances to airflow offered by the collapsible segment and the small airways are significant throughout forced expiration; their combined effect is needed to adequately match the inspiratory and expiratory flow-volume loops. Despite the limitations of this lumped single-compartment model, a remarkable agreement with airflow and expired gas concentration measurements is obtained for normal subjects. Furthermore, the model provides insight into the important dynamic interactions between ventilation and perfusion during the FVC maneuver.

Rapid technique of occlusion of the venae cavae for total cardiopulmonary bypass during repeat cardiac operations.

A new technique of occlusion of the venae cavae utilizing a cannula with an inflatable balloon cuff is described.

Torn ascending aorta missed by transesophageal echocardiography.

Transesophageal echocardiography has become a commonly used screening tool for traumatic tears of the descending aorta. The role of transesophageal echocardiography for ascending aortic tears is not yet well-defined. We report an ascending aortic tear imaged by aortography but missed on transesophageal echocardiography.

Simple technique of left heart bypass.

Left heart bypass is typically established by left atrial appendage cannulation. We report a technique using inferior pulmonary vein cannulation, which is technically simpler. We have used this technique in 20 cases with reliable venous inflow.

Giant left atrial intrapericardial aneurysm: noninvasive preoperative imaging.

Congenital giant intrapericardial aneurysms of the left atrium are rare. A 17-year-old boy presented with paroxysmal episodes of palpitations, chest pain, and dyspnea. A chest roentgenogram showed an enlarged left cardiac silhouette. Transthoracic echocardiography imaging showed an intrapericardial aneurysm of the left atrium. Cardiac magnetic resonance imaging confirmed the diagnosis and delineated adjacent structures to plan the surgical resection. We have found no previous reports of cases of diagnosis and preoperative assessment based solely on noninvasive imaging.

Hemoptysis secondary to pulmonary pseudoaneurysm 30 years after a gunshot wound.

A 49-year-old man presented with intermittent hemoptysis from a traumatic pulmonary artery pseudoaneurysm 30 years following a thoracic gunshot wound. The patient was asymptomatic for 28.5 years, when he began experiencing recurrent hemoptysis, chest pain, and a cough. A left lower lobe mass on chest x-ray film was investigated with contrast-enhanced computed tomography and pulmonary angiogram confirming a 1.5-cm pseudoaneurysm. Intraluminal coil embolization was attempted, but a left lower lobectomy was ultimately necessary to treat persistent hemoptysis.

Tension pneumothorax during extracorporeal membrane oxygenation.

Life-threatening tension pneumothorax in neonates on extracorporeal membrane oxygenation (ECMO) has been associated with an increase in arterial oxygen tension and a decrease in peripheral perfusion, followed by a decrease in ECMO flow with progressive hemodynamic deterioration. To investigate this triad, chest tubes were placed bilaterally in 9 dogs to allow injection of air to produce tension pneumothorax. Six dogs were subsequently placed on standard venoarterial ECMO before the reinduction of tension pneumothorax. Measured values included arterial pulse pressure, inferior vena cava pressure, systemic arterial blood gases, peripheral arterial oxygen saturation, mixed venous oxygen saturation, and left heart cardiac output. Oxygen delivery was calculated from directly measured values. Each of the 6 dogs on ECMO demonstrated the triad of increased arterial oxygen tension (92 +/- 7 to 325 +/- 20 mm Hg; p less than 0.05), decreased peripheral perfusion (as evidenced by a decrease in pulse pressure from 55 +/- 4 to 31 +/- 5 mm Hg; p less than 0.05), and decreased mixed venous oxygen saturation (71% +/- 3% to 22% +/- 2% saturation; p less than 0.05) followed by a lower ECMO flow with progressive hemodynamic deterioration (oxygen delivery decreased from 285 +/- 11 to 111 +/- 12 mL/min; p less than 0.05). Aspiration of the intrathoracic air allowed return to baseline ECMO flow and hemodynamic stability in all dogs. The triad of increased arterial oxygen tension and decreased peripheral perfusion (as evidenced by a lower arterial pulse pressure and lower mixed venous oxygen saturation) followed by decreased ECMO flow with progressive hemodynamic deterioration consistently appears when tension pneumothorax occurs on ECMO.

Viable cryopreserved aortic homograft for aortic valve endocarditis and annular abscesses.

Six consecutive patients with active aortic valve endocarditis, including 2 with extensive subannular aortic root abscess, were successfully treated with viable cryopreserved homograft aortic valve replacement. Two patients required extensive aortic root reconstruction with an appropriately trimmed aortic homograft to cover large abscess cavities. All patients showed resolution of infection with no perioperative mortality or clinically significant morbidity. Three patients had a minor degree of aortic insufficiency on postoperative echo-Doppler study. On follow-up at 6 to 48 months, all patients were in New York Heart Association functional class I. The resistance of the unstented homograft to infection makes it an attractive choice for patients requiring aortic valve replacement for active endocarditis. The results of surgical intervention in patients with extensive aortic root involvement may be further improved by the flexibility afforded by the homograft to be "custom-fit" to the abnormal aortic root and the ability to achieve secure abnormal aortic root and the ability to achieve secure valve fixation without use of prosthetic material.