Adult Congenital Heart Disease

The 30-Year Outcomes of Tetralogy of Fallot According to Native Anatomy and Genetic Conditions. Blais S, Marelli A, Vanasse A, Dahdah N, Dancea A, Drolet C, Colavincenzo J, Vaugon E, Dallaire F.Can J Cardiol. 2021 Jun;37(6):877-886. doi: 10.1016/j.cjca.2020.10.002. Epub 2020 Oct 12.PMID: 33059007   Take Home Points: Among all TOF subjects, ±20% have TOF-PA The prevalence of genetic conditions is higher in the TOF-PA group compared to the cTOF group In non-syndromic cTOF patients, long term survival is excellent For both cTOF and TOF-PA, mortality before surgical correction is about 30%, but less frequent in the non-syndromic patients The predicted survival for patients with TOF-PA and those with genetic conditions are considerably poorer Commentary from Dr. Blanche Cupido (Cape Town, South Africa), chief section editor of ACHD Journal Watch: Surgically corrected Tetralogy of Fallot (TOF) overall has an excellent survival – up to 97%. The variant group that has pulmonary atresia or genetic outcomes have been thought to subtend poorer outcomes. Long term data relating outcomes to these subgroups are lacking. The TRIVIA (Tetralogy of Fallot Research for Improvement of Valve Replacement Intervention: A Bridge across the Knowledge Gap) study, based in the Quebec Registry, Montreal, aimed to assess the long-term outcomes of TOF from birth to age 30, based on native anatomic subtype and the presence of genetic syndromes.   The primary outcome was all-cause mortality. Secondary outcomes included cardiovascular interventions and cardiovascular unplanned hospitalisations for adverse cardiac events. The TOF anatomic types were categorized as: 1. Classic stenotic TOF (cTOF), 2. TOF with pulmonary atresia (TOF-PA). The presence of genetic conditions were categorized as: 1. Trisomy 21, 2. 22q11 deletion, 3. Clinical or genetic diagnosis other than trisomy 21 or 22q11 deletion, 4. Non-syndromic subjects.   A total of 960 TOF patients were included in the final analysis, with a median follow-up period of 17.1 years. One-hundred and fifty-eight patients (16%) were followed up for >30 years. cTOF, as expected, was more prevalent than TOF-PA (78.5% vs 21.5%). The presence of a genetic condition was more frequently seen in those with TOF-PA compared to cTOF (28.2% vs 17.5%), mainly due to the prevalence of 22q11 deletions in the TOF-PA group. The proportion of patients with trisomy 21 was higher in the cTOF vs TOF-PA group (4.8% vs 2.4%). Figure 1 below shows the distribution of TOF clinical profiles:     A total of 142 deaths occurred. Causes of death was similar between the 2 groups. The majority of deaths were due to cardiovascular causes (64.8%) – mainly peri-operative complications. Nearly half of the deaths occurred before surgical correction – even across surgical eras.     The 30 year survival varied greatly between the 2 categories, with TOF-PA having a worse prognosis. Furthermore, genetic syndromes also resulted in a markedly varied outcome: Non-syndromic cTOF patients had the highest survival (95% at 30 years). The non-syndromic TOF-PA had an estimated 30 year survival of 78%. There was significant heterogeneity of the effect of genetic syndromes in each of the anatomic TOF types. 22q11 deletion had a similar outcome to non-syndromic patients, whereas trisomy 21 and other syndromes portended a worse prognosis.     Over 2000 (n=2305) cardiovascular interventions were recorded during follow-up. Surgical correction of TOF accounted for most. The second most frequent intervention was percutaneous pulmonary valvuloplasty (40% of all interventions in cTOF and TOF-PA).     The overall rate of unplanned hospitalisations for a cardiac event was low in both anatomic groups of TOF patients (mean rate <0.1 hospitalisations per patient year) with cardiac infections accounting for 40%, arrythmias for 25% and heart failure for 7%.    

A Risk Score for Adults With Congenital Heart Disease Undergoing Heart Transplantation. Seese L, Morell VO, Viegas M, Keebler M, Hickey G, Wang Y, Kilic A.Ann Thorac Surg. 2021 Jun;111(6):2033-2040. doi: 10.1016/j.athoracsur.2020.05.154. Epub 2020 Jul 29.PMID: 32738222   Take Home Points: The authors created a 13-point risk score predictive of mortality within 1 year of orthotopic heart transplantation, of possible use in informing patient selection for these types of transplants. The risk score, based on a North American/ USA cohort, was as follows: 0 points predicted a 1 year mortality of 14.6% and 13 points 49.9%, with a graduation seen in between. Commentary by Dr. Simon MacDonald (London, UK), section editor of ACHD Journal Watch: Advances in congenital heart disease treatment have allowed a greater number of congenital patients to survive to adulthood. Many require advanced heart failure treatment and consideration of heart transplantation. This can be orthotopic (where the recipients heart is removed for the donor heart ) or heterotopic (where the donor heart assists the failing recipient heart in a ‘piggy-back’ arrangement). The authors studied orthotopic transplantation, looking to derive and validate a risk score for 1 year mortality in ACHD patients.   They studied patients ≥18 years of age with congenital heart disease undergoing orthotopic heart transplantation between 1987 and 2018, within the United Network for Organ Sharing (UNOS) registry. This is a United States organisation that manages the US organ transplant system. Patients who received heterotopic, redo transplantation or multiorgan transplant (including heart-lung transplants) were excluded.   They split the study population into 2 groups; a derivation cohort of 66% of the patients and a validation cohort of the remaining 34% to test the score. A secondary outcome was risk score stratified rates of major morbidities and hospital length of stay. It was not stated how this randomisation occurred.   The UNOS registry contains 542 variables and they were evaluated using univariate logistic regression in the derivation cohort, adjusting for transplant year and average volume of transplant at each centre.   They used 1388 ACHD OHT patients, mean age 34.6≥13.0 years and women 38%. The majority of patients were white (83.2%). In terms of donors, mean age was 27.6≥11.3yrs, with traumatic injury the most common donor mechanism of death (50%, n=692).   Initial exploratory logistic regression analysis identified 26 covariates for 1 year mortality in the derivation cohort. Final multivariable model included 8 variables (p<0.05); greater than 30 years of age, pretransplant mechanical ventilation, pretransplant dialysis, serum bilirubin≥ 2.4mg/dl, male sex of donor, and later transplant era (2000-2010) (table 2 below) before they settled on the risk factors in table 3.   The authors comment that many ACHD patients have unique challenges such as need for complex vascular reconstruction, elevated panel reactive antibodies and ABO blood group sensitization and that, when listed for OHT, they are less likely to receive a transplant than with a patient with acquired heart failure.   The tool seemed predictive of 1 year mortality and adverse outcomes, with a graded increase in predicted and observed rates of 1 year mortality as the score increased from 0 to 13. Patients with a score≥4 had substantially higher risks of mortality at 30 days, 90 days and 1 year. Pretransplant dialysis dependence and mechanical ventilation conferred the highest risk.   There was not enough data to do subgroup analysis on the different types of ACHD needing transplant, nor was the numbers and types of simple to complex ACHD seen stated and the numbers and types of prior operation stated. Missing data in the transplant dataset was a problem in this regard. The authors state that failed Fontan palliation and single ventricle anatomy predicted OHT mortality with increased graft failure, infection and bleeding in an earlier study. The study was retrospective and only based in a North American cohort. Testing in European and Eastern cohorts would have given further confidence for the score in other populations. The Eisenmenger population, who largely get heart-lung transplantation, would also have been excluded from the study.   The risk score may help in the pretransplant assessment of ACHD patients regarding patient selection and provides a step forward in evaluating complex ACHD patients, suggesting future multi-centre studies of selection criteria.   

Longitudinal Changes in Exercise Capacity in Patients Who Underwent Ross Procedure and Mechanical Aortic Valve Replacement: Does the Type of Surgery Matter? Takajo D, Kota V, Balakrishnan PPL, Gayanilo M, Sriram C, Aggarwal S.Pediatr Cardiol. 2021 Jun;42(5):1018-1025. doi: 10.1007/s00246-021-02575-4. Epub 2021 Mar 8.PMID: 33682063   Take Home Points: Young children who undergo aortic valve replacement experience a decrease in exercise capacity in long term follow-up. On the other hand, young children who had undergone the Ross procedure have a preserved exercise capacity. This was due to a prosthesis-patient-mismatch, in patients who underwent aortic valve replacement, as they grow; while patients who had the Ross procedure had a preserved exercise capacity due to the growing autograft. Commentary from Dr. MC Leong (Kuala Lumpur), section editor of ACHD Journal Watch: The Ross procedure (RP) and aortic valve replacement (AVR) are two commoner procedures employed in the treatment of severe aortic valve disease in children. In the former, the single valve disease is converted into a two-valve disease and often the long-term outcome depends heavily on the surgical expertise. However, the autograft grows with the growing child and it is favoured over AVR in the treatment of very young children due to the concerns of prosthesis-patient mismatch and the warfarin treatment, diet restrictions, and the inherent complications that come along with a mechanical AVR.   In this study, the authors retrospectively examined the exercise capability between children who underwent RP and AVR as well as the longitudinal changes in exercise performance after these procedures in their institution from 2005 and 2020. Patients with other concomitant congenital heart disease or pacemaker/defibrillator were excluded. Patients were considered to have a longitudinal assessment if there is more than one cardiopulmonary exercise tests after the initial aortic valve intervention.   A total of 47 patients were included - RP [n=23, 73.9% male, age at surgery 11.2 (4.5–15.9) years] vs. AVR [n=24, 88% mechanical AVR, 60.9% male, age at surgery 15.1 (12.8–19.4) years] (Table 1). At baseline, the cardiopulmonary exercise parameters were largely comparable between groups except for the % VO2. Only 23 patients had longitudinal assessments - 12 patients in the RP group [58.3% male, inter-test duration 7.1 (5.8–9.5) years] (Table 3) vs n 11 patients in the AVR group [54.5% male, inter-test duration 5 (3.7–7.1) years] (Table 4). In the RP group, there was a significant improvement in the VE/VCO2 at anaerobic threshold during follow-up. The other parameters showed no significant change. However, in the AVR group, there was a decrease in (i) peak exercise capacity or VO2 (34.2 vs. 26.2 vs., p=0.006), (ii) %VO2 (85 vs. 59, p=0.003) (Figure 2), (iii) METS (9.8 vs.7.5, p=0.006), and (iv) % oxygen pulse (111 vs. 94, p=0.04). There were more patients with abnormal %VO2 at follow-up (45% vs. 100% of patients). The drop in the CPET parameter, according to the authors, was likely attributed to the prosthesis-patient mismatch in these growing patients. This drop was not seen in the RP group underscoring the growth potential of the autograft.             One of the biases in this study was the presence of a higher number of patients in the AVR group who were on beta blockers (8, 33.3%) and Digoxins (4, 16.7%) compared to the that of the RP (5, 21.7% and 1, 4.3%) (Table 1). These patients may have chronotropic incompetence which may lower the cardiac output, thus affecting exercise capacity.