Mi-Young Cho

The fate of small-diameter homografts in the pulmonary position

BACKGROUND Limited durability is expected for small homograft valves that are used to correct congenital cardiac disease. METHODS All 76 homograft valves with an internal annulus diameter ranging from 8 to 13 mm that were implanted from 1987 through 2000 in the pulmonary position were retrospectively analyzed. In each case, homograft size was normalized to the patients body surface area: z-value. For 93% (14 of 15) of the 8 to 9 mm grafts, z was less than 2. For 56% (5 of 9) of the 10 mm grafts and 98% (51 of 52) of the 11 to 13 mm allografts, z was greater than 2. Survival and freedom from complications were estimated by the Kaplan-Meier method. Homograft failure was defined as homograft replacement or late death; significant dysfunction, as homograft obstruction with an echo-Doppler gradient greater than 50 mm Hg or grade III or IV valvular insufficiency. The log-rank test was used to compare outcomes. RESULTS Seven patients died early after operation; three, late. Survival was 86.5% +/- 3.8% at 1 year and remained stable during the succeeding years. Freedom from failure for all homografts was 90.6% +/- 3.7%, 71.8% +/- 6.9%, and 61.8% +/- 9.0% at 1, 5, and 10 years, respectively. Corresponding freedom from significant dysfunction was 87.6% +/- 4.1%, 51.2% +/- 7.4%, and 10.1% +/- 8.3%. The smaller homografts (z less than 2) failed and deteriorated faster (p < 0.0001): only 32.1% +/- 13.0% were still functioning at 24 months. The larger grafts (z at least 2) retained function for the first 4 years, and 73.7% +/- 10.4% had not yet failed at 10 years. CONCLUSIONS Smaller (z less than 2) homografts (the great majority of 8 to 9 mm grafts) have to be replaced early, usually within 2 years of implantation. Larger (z at least 2) grafts (nearly all 11 to 13 mm grafts) show remarkable durability and are suitable valved conduits for establishing right ventricle to pulmonary artery continuity in neonates and young infants.

Results of Arterial Switch Operation for Primary Total Correction of the Taussig-Bing Anomaly

BACKGROUND This study evaluates the results of the arterial switch operation for early total repair of double-outlet right ventricle with subpulmonary ventricular septal defect (the Taussig-Bing heart). METHODS From 1986 through April 2003, 27 patients with Taussig-Bing anomaly underwent arterial switch operation. Twenty patients were neonates (n = 11) or infants younger than 3 months (n = 9). Obstruction of aortic arch (n = 19) or subaortic right ventricular outflow tract obstruction (n = 20) and unusual coronary artery patterns (n = 19) were common. Total correction as a single procedure was performed in 21 patients. Events are depicted by Kaplan-Meier curves. RESULTS There was 1 patient hospital death at 2 months after repair. One patient died late that was not cardiac related. Survival was 92% +/- 6% at 8 months and remained constant thereafter. Four patients underwent reoperation (1 for residual aortic arch obstruction and 3 for subvalvular and valvular pulmonary stenosis). Freedom from reoperation decreased to stabilize at 83% +/- 8% after 2 years. The risk to have right ventricular outflow tract obstruction develop was 33% +/- 10% at 1 year, increasing slowly and leveling out at 57% +/- 12% at year 5 and thereafter. Statistical analysis revealed no significant risk factor for death or need for reoperation. CONCLUSIONS The Taussig-Bing anomaly should be corrected in the neonatal period or in early infancy by arterial switch operation, closure of the ventricular septal defect, and simultaneous correction of associated cardiovascular anomalies as a one-stage procedure. Right ventricular outflow tract obstruction often complicates the postoperative course and is the main cause for reintervention.

Long-Term Results After Repair of Complete Atrioventricular Septal Defect With Two-patch Technique

BACKGROUND Surgical management of patients with complete atrioventricular septal defect (AVSD) has advanced over the last decades. Definitive early surgical repair for AVSD has become the treatment of choice at many centers. This trend has contributed to the recent decline in postoperative mortality and good long-term results. METHODS We reviewed long-term results of 100 consecutive patients with complete AVSD undergoing definitive early repair with a two-patch technique and complete cleft closure operated on between June 1999 and June 2009. Valve performance, mortality, morbidity, and indications for reoperation were retrospectively studied. RESULTS Median age at operation was 3.8 months (range, 15 days to 4.7 years); median weight was 5.0 kg (range, 3.0 to 19 kg). Follow-up was 99% complete (mean 58 months; range, 1 to 120 months). Early definitive repair was performed in all patients who initially presented to our institution over the study period. There was no perioperative, in-hospital mortality, or late mortality. At the latest follow up, left atrioventricular valve (LAVV) regurgitation was absent or trace in 80 patients (80%), mild to moderate in 15 patients (15%), and moderate to severe in 4 patients (4%). Right AV valve regurgitation was none or trace in 86 patients (86%), mild to moderate in 11 patients (11%), and moderate to severe in 2 patients (2%). Actuarial freedom from reoperation for LAVV dysfunction at 1, 3, 5, and 10 years was 98%, 95%, 94%, and 94%, respectively. Actuarial freedom from reoperation for left ventricular outflow tract obstruction at 1, 3, 5, and 10 years was 100%, 99%, and remained constant by 99% at 5 and 10 years. CONCLUSIONS Definitive early repair for complete AVSD can be performed with excellent results. The two-patch technique with complete cleft closure is a safe and reproducible surgical method that can achieve very low mortality and stable long-term outcomes, even in neonates.

Modified Ross–Konno procedure in children: subcoronary implantation technique with Konno incision for annular and subannular hypoplasia†

OBJECTIVES The technique of subcoronary autograft implantation for the Ross procedure has shown excellent durability of aortic valve function in adults. However, its use in children with hypoplastic aortic annulus or multilevel left ventricular outflow tract obstruction (LVOTO) was traditionally precluded. We combined this technique with a Konno incision and evaluated LVOTO relief and durability of the autograft function in growing patients. METHODS Between January 2012 and January 2017, 13 patients with severe LVOTO and hypoplastic aortic annulus underwent Ross-Konno procedure with subcoronary autograft implantation. The median age at operation was 14 months. Six were infants. Concomitant procedures included resection of endocardial fibroelastosis (n = 9), mitral valvuloplasty (n = 2) and aortic arch repair (n = 1). The Konno incision was enlarged with a patch. The autograft was implanted beneath the ostia of the coronary arteries, retaining external support by the native aortic annulus. RESULTS A newborn with hypoplastic left heart complex and Turner syndrome died in hospital: early mortality of 7.7%. No residual LVOTO or autograft regurgitation was observed at discharge. At a median follow-up of 20 months, no death had occurred. No catheter or surgical reintervention on the aortic valve or any LVOT site was needed. All peak pressure gradients across the LVOT were <10 mmHg. No autograft regurgitation was detected. CONCLUSIONS The Ross procedure using subcoronary implantation technique combined with LVOT Konno enlargement is feasible even in patients with multilevel LVOTO and marked size discrepancy between the autograft and native aortic annulus. Longer follow-up is indicated to confirm the expected durability of the autograft function.

Accuracy of predicted haemoglobin concentration on cardiopulmonary bypass in paediatric cardiac surgery: effect of different formulae for estimating patient blood volume

Introduction: When applying a blood-conserving approach in paediatric cardiac surgery with the aim of reducing the transfusion of homologous blood products, the decision to use blood or blood-free priming of the cardiopulmonary bypass (CPB) circuit is often based on the predicted haemoglobin concentration (Hb) as derived from the pre-CPB Hb, the prime volume and the estimated blood volume. We assessed the accuracy of this approach and whether it may be improved by using more sophisticated methods of estimating the blood volume. Patients and Methods: Data from 522 paediatric cardiac surgery patients treated with CPB with blood-free priming in a 2-year period from May 2013 to May 2015 were collected. Inclusion criteria were body weight <15 kg and available Hb data immediately prior to and after the onset of CPB. The Hb on CPB was predicted according to Fick’s principle from the pre-CPB Hb, the prime volume and the patient blood volume. Linear regression analyses and Bland-Altman plots were used to assess the accuracy of the Hb prediction. Different methods to estimate the blood volume were assessed and compared. Results: The initial Hb on CPB correlated well with the predicted Hb (R2=0.87, p<0.001). A Bland-Altman plot revealed little bias at 0.07 g/dL and an area of agreement from -1.35 to 1.48 g/dL. More sophisticated methods of estimating blood volume from lean body mass did not improve the Hb prediction, but rather increased bias. Conclusion: Hb prediction is reasonably accurate, with the best result obtained with the simplest method of estimating the blood volume at 80 mL/kg body weight. When deciding for or against blood-free priming, caution is necessary when the predicted Hb lies in a range of ± 2 g/dL around the transfusion trigger.

Assessment of a congenital heart surgery programme: a reappraisal

OBJECTIVES To assess our practice according to the Society of Thoracic Surgeons and the European Association for Cardio-Thoracic Surgery (STS-EACTS) Mortality Score and to the new concept of unit performance. METHODS All main procedures carried out in the years 2012-2016 were analysed. The STS-EACTS model-based mortality risk procedure was used to calculate expected mortality. Surgical performance was estimated as the Aristotle complexity score multiplied by hospital survival. Unit performance was defined as surgical performance multiplied by the number of procedures. RESULTS In total, 2435 procedures were analysed. One hundred and two deaths (95% confidence interval 71-135 deaths) were expected; 43 patients died after operation. Observed mortality divided by expected mortality was 0.42. The ratio ranged from 0.23 (year 2014) to 0.59 (year 2013) and was <0.6 in all STS-EACTS mortality categories. The difference between observed and expected mortality was highly significant: 1.8% vs 4.2% (P-value <0.0001). Observed surgical and unit performances were, higher than expected performances every year. Achieved surgical performance was the highest in year 2012 (7.28 ± 2.54) and the lowest in year 2014 (7.04 ± 2.52). The highest figure of unit performance was achieved in year 2016: 3980 points. CONCLUSIONS The STS-EACTS score, currently recognized as a sound instrument to assess mortality after congenital heart surgery, overestimated postoperative mortality. If these results are confirmed by other centres, the model should be recalibrated to match the current surgical practice. Although surgical performance can evaluate outcome quality, it does not include case volume activity. Unit performance provides this information, and it integrates quality and quantity into a single value.

Results of aortic valve repair using decellularized bovine pericardium in congenital surgery

OBJECTIVES The search for an optimal patch material for aortic valve reconstruction (AVR) is an ongoing challenge. In this study, we report our experience of AVR using decellularized bovine pericardial patch material in congenital heart surgery. METHODS Data of 40 consecutive patients who underwent AVR using the CardioCel® patch (Admedus Regen Pty Ltd, Perth, WA, Australia) between February 2014 and August 2016 were retrospectively reviewed. The median age of the patients at operation was 9 (2-34) years, and 18 patients were younger than 7 years. Twenty-six patients initially presented with aortic valve insufficiency (AI) and 14 with stenosis. Clinical and echocardiographic data were available until August 2017 for a median postoperative follow-up (FU) of 22 (6-42) months. RESULTS Nine of 40 (23%) patients experienced an event during FU (death: n = 1, 2.5%; reoperation: n = 8, 20%). Overall, the probability of freedom from reoperation or death was 97 ± 3%, 76 ± 9% and 57 ± 12% at 12, 24 and 36 months of FU, respectively. Reason for reoperation was stenosis in 3 (37.5%) patients, insufficiency in 4 (50%) patients and 1 (12.5%) patient was diagnosed with aortic valve endocarditis. Of the remaining 31 patients, 2 patients are scheduled for reoperation (aortic valve stenosis: n = 1 and AI: n = 1) and 9 patients exhibit worsening of aortic valve function with moderate AI. Freedom from developing combined end point [death/reoperation/moderate degree of aortic valve dysfunction (aortic valve stenosis, AI)] after AVR was 92 ± 5%, 55 ± 9% and 28 ± 9% at 12, 24 and 36 months, respectively. CONCLUSIONS AVR using decellularized bovine pericardial patch material in patients with congenital aortic valve disease show unsatisfactory results within the first 3 years of FU.

Additional veno-venous gas exchange as a problem-solving strategy for an oxygenator not transferring oxygen in paediatric cardiopulmonary bypass†

OBJECTIVES Oxygenator failure during cardiopulmonary bypass constitutes a life-threatening event, especially when perfusion is conducted under normothermia. An alternative solution to emergency oxygenator changeover is described. METHODS A supplementary oxygenator is added in the venous line without interrupting perfusion. De-airing is achieved through the cardiotomy reservoir. Oxygen supply is adapted to ensure physiologic partial oxygen pressure. RESULTS On 5 occasions in the past 4 years, Capiox Baby FX 05 oxygenator (n = 4) and Capiox FX15 (n = 1) failed to exchange blood gases after bypass run ranging from 290 min to 563 min. Hypoxia ensued with partial oxygen pressure values of 49-79 mmHg with a fraction of inspired oxygen of 1. An additional veno-venous Terumo Capiox FX 05 oxygenator immediately improved oxygenation with resulting partial oxygen pressure increasing to at least 291 mmHg. CONCLUSIONS An additional veno-venous oxygenator effectively corrects failing oxygenator during cardiopulmonary bypass. The method does not require circulation arrest. It does not carry the risk of air embolism. It can be carried out without any help from a second perfusionist or member of operation team.