Page 18 - ANZCP Gazette AUG 2023

Reason for Reintervention.
As the 2006-2021 patients grow older we should see the pie chart morph into one more like the 1980-2005 one. It is known that post ToF repair pulmonary valve issues generally start to show at around 30-40 years of age. Both charts reflect current follow-up. The PV repair/ replace numbers include replacement of conduits where patients had outgrown the conduit placed as part of the primary repair. Once again only one reintervention per patient has been counted although some have had more than one reintervention.
Discussion
Many papers5-16 have been looking specifically at the TA approach have been included in the Meta Analysis of ToF repair by Romeo et al.4 Those included in the table have been chosen as they represent doing at least one case per month in the reporting institution so that there should be a reasonable level of familiarity with the approach. Hickey19 has been added to this because of the large number of patients, a very long study period and to provide contrast in results where surgical approach is not considered.
Mean ages at repair are reflective of differences in institutional guidelines as to when the operation should be completed and in some cases the age of the patient at primary presentation for diagnosis.
The meta-analysis4 did not look at weight or BSA at primary repair and few papers documented weight with most using age as the determinant of when to proceed with repair.
The change in CPB temperature management to mild to moderate hypothermia was seen for both adult and paediatric CPB over the decades under study. As cardiac surgical staff became more aware of the benefits of warmer surgery the average temperature increased.
As mentioned in the results bypass time and cross clamp times are surgeon dependent. Analysis of individual surgeons times over a number of years showed significant differences in both parameters.
While Bubbler oxygenators were in common use large priming volumes were required. This corresponds to large amounts (compared to now) of donor blood to avoid acute haemodilution on bypass, and crystalloid/colloid prime components. The median weight of patients on Bubbler oxygenators was >10kg requiring around 600-900mls of donor blood. Our current protocol for patients >10kg is to decide whether an asanguinous prime can be used.
Length of stay increased. The possible reason is that we are dealing with more patients with comorbidities, and the other health issues are being treated during the same admission, or the comorbidities make recovery from the repair more time consuming. I have not analysed the frequency of comorbidity. This however should have been offset to some degree by the more frequent occurrence of surgery on day of admission. Length of stay is also affected by hospital protocol with respect to time of discharge. Most discharges took place between 9am and midday after morning rounds, fewer in the afternoon and almost none in the evening.
Overall mortality has remained small over the time period. Late deaths are probably under reported due to loss of follow-up but are on par with other reported results.
The average annual rate of reintervention over 40 years is at best 0.5% per annum, but given number of patients lost to follow-up this is probably more than the 1.1 % per annum for the later cohort.
The year of the start of reintervention for the <1 yr cohort coincides with marked increase in the use of echocardiography as a tool in follow-up. Earlier
16 SEPTEMBER 2023 3SCTS SPECIAL EDITION | www.anzcp.org