Survival After Intervention for Single-Ventricle Heart Disease Over 15 Years at a Single Institution

Days alive and out of hospital for children born with single-ventricle heart disease

BACKGROUND

This study describes the illness burden in the first year of life for children with single-ventricle heart disease, using the metric of days alive and out of hospital to characterize morbidity and mortality.

METHODS

This is a retrospective single-centre study of single-ventricle patients born between 2005 and 2021 who had their initial operation performed at our institution. Patient demographics, anatomical details, and hospitalizations were extracted from our institutional single-ventricle database. Days alive and out of hospital were calculated by subtracting the number of days hospitalized from number of days alive during the first year of life. A multivariable linear regression with stepwise variable selection was used to determine independent risk factors associated with fewer days alive and out of hospital.

RESULTS

In total, 437 patients were included. Overall median number of days alive and out of hospital in the first year of life for single-ventricle patients was 278 days (interquartile range 157-319 days). In a multivariable analysis, low birth weight (<2.5kg) (b = -37.55, p = 0.01), presence of a dominant right ventricle (b = -31.05, p = 0.01), moderate-severe dominant atrioventricular valve regurgitation at birth (b = -37.65, p < 0.05), index hybrid Norwood operation (b = -138.73, p < 0.01), or index heart transplant (b = -158.41, p < 0.01) were all independently associated with fewer days alive and out of hospital.

CONCLUSIONS

Children with single-ventricle heart defects have significant illness burden in the first year of life. Identifying risk factors associated with fewer days alive and out of hospital may aid in counselling families regarding expectations and patient prognosis.

Contemporary outcomes for functional single ventricle with total anomalous pulmonary venous connection

OBJECTIVE

In 2004, we reported improved early survival for patients with functional single ventricle anatomy and total anomalous pulmonary venous connection. This study sought to discover if outcomes have been ameliorated in the contemporary era.

METHODS

This was a single-center review of patients with single ventricle anatomy and total anomalous pulmonary venous connection who were admitted from 1984 to 2021. The cohort was divided into similarly sized groups by date of admission: Era 1: 1984 to 1992, Era 2: 1993 to 2007, and Era 3: 2008 to 2021. Survival was compared, and Cox proportional hazards models were used to evaluate the likelihood of mortality.

RESULTS

We included 190 patients with single ventricle anatomy and total anomalous pulmonary venous connection. Unbalanced atrioventricular canal defect (70%) was the most common primary diagnosis. The most common type of total anomalous pulmonary venous connection was supracardiac (49%). Approximately one-third (32%) of patients had pulmonary venous obstruction. There were no significant differences in patient characteristics across eras. Early survival after initial palliative operation improved between Eras 1 and 2, and then remained stable in Era 3. Overall survival improved from Era 1 to Eras 2 and 3 (P < .001), but not between Era 2 and 3. Survival to 10 years by Eras 1 to 3 was 15%, 51%, and 54%, respectively. The anatomic features associated with worse survival were hypoplastic left heart syndrome diagnosis (hazard ratio, 1.60; 1.04-2.57) and pulmonary venous obstruction (hazard ratio, 1.80; 1.24-2.69).

CONCLUSIONS

Overall survival for patients with single ventricle anatomy and total anomalous pulmonary venous connection has plateaued since the early 2000s. Even in the most recent era, survival to age 10 years remains less than 60%. Risk factors for mortality include the diagnosis of hypoplastic left heart syndrome and pulmonary venous obstruction. Further studies should focus on identification of the pathophysiological factors underlying the increased mortality.

Textbook Outcome for Superior Cavopulmonary Connection: A Metric for Single Ventricle Heart Surgery

Background: To develop a more holistic measure of congenital heart center performance beyond mortality, we created a composite "textbook outcome" (TO) for the Glenn operation. We hypothesized that meeting TO would have a positive prognostic and financial impact. Methods: This was a single center retrospective study of patients undergoing superior cavopulmonary connection (bidirectional Glenn or Kawashima ± concomitant procedures) from 2005 to 2021. Textbook outcome was defined as freedom from operative mortality, reintervention, 30-day readmission, extracorporeal membrane oxygenation, major thrombotic complication, length of stay (LOS) >75th percentile (17d), and mechanical ventilation duration >75th percentile (2d). Multivariable logistic regression and Cox proportional hazards modeling were used. Results: Fifty-one percent (137/269) of patients met TO. Common reasons for TO failure were prolonged LOS (78/132, 59%) and ventilator duration (67/132, 51%). In multivariable analysis, higher weight [odds ratio, OR: 1.44 (95% confidence interval, CI: 1.15-1.84), P = .002] was a positive predictor of TO achievement while right ventricular dominance [OR 0.47 (0.27-0.81), P = .007] and higher preoperative pulmonary vascular resistance [OR 0.58 (0.40-0.82), P = .003] were negative predictors. After controlling for preoperative factors and excluding operative mortalities, TO achievement was independently associated with a decreased risk of death over long-term follow-up [hazard ratio: 0.50 (0.25-0.99), P = .049]. Textbook outcome achievement was also associated with lower direct cost of care [$137,626 (59,333-167,523) vs $262,299 (114,200-358,844), P < .0001]. Conclusion: Achievement of the Glenn TO is associated with long-term survival and lower costs and can be predicted by certain risk factors. As outcomes continue to improve within congenital heart surgery, operative mortality will become a less informative metric. Textbook outcome analysis may represent a more balanced measure of a successful outcome.

Textbook outcome for the Norwood operation-an informative quality metric in congenital heart surgery

Objectives

To develop a more holistic measure of center performance than operative mortality, we created a composite "textbook outcome" for the Norwood operation using several postoperative end points. We hypothesized that achieving the textbook outcome would have a positive prognostic and financial impact.

Methods

This was a single-center retrospective study of primary Norwood operations from 2005 to 2021. Through interdisciplinary clinician consensus, textbook outcome was defined as freedom from operative mortality, open or catheter-based reintervention, 30-day readmission, extracorporeal membrane oxygenation, cardiac arrest, reintubation, length of stay >75%ile from Society of Thoracic Surgeons data report (66 days), and mechanical ventilation duration >75%ile (10 days). Multivariable logistic regression and Cox proportional hazards modeling were used to determine predictive factors for textbook outcome achievement and association of the outcome with long-term survival, respectively.

Results

Overall, 30% (58/196) of patients met the textbook outcome. Common reasons for failure to attain textbook outcome were prolonged ventilation (68/138, 49%) and reintubation (63/138, 46%). In multivariable analysis, greater weight (odds ratio [OR], 2.11; 95% confidence interval [CI], 1.17-3.95; P = .02) was associated with achieving the textbook outcome whereas preoperative shock (OR, 0.36; 95% CI, 0.13-0.87; P = .03) and longer bypass time (OR, 0.99; 95% CI, 0.98-1.00; P = .002) were negatively associated. Patients who met the outcome incurred fewer hospital costs ($152,430 [141,798-177,983] vs $269,070 [212,451-372,693], P < .001), and after adjusting for patient factors, achieving textbook outcome was independently associated with decreased risk of all-cause mortality (hazard ratio, 0.45; 95% CI, 0.22-0.89; P = .02).

Conclusions

Outcomes continue to improve within congenital heart surgery, making operative mortality a less-sensitive metric. The Norwood textbook outcome may represent a balanced measure of a successful episode of care.

The impact of early diagnosis of fetal single-ventricle cardiac defects on reproductive choices

BACKGROUND

Congenital heart defects are the most common fetal anomaly. Congenital heart defects with single-ventricle cardiac defects have high mortality rates, and in pregnancies diagnosed with this condition, patients are often offered termination of pregnancy as an option.

OBJECTIVE

This study aimed to investigate the relationship between gestational age at diagnosis and reproductive choices in fetuses diagnosed with single-ventricle cardiac defects.

STUDY DESIGN

This was a retrospective single-center cohort study in which 158 patients with a fetal diagnosis of single-ventricle cardiac defects were reviewed. Cases were categorized as isolated or complex. Complex cases included fetuses with single-ventricle cardiac defects in addition to other fetal extracardiac anomalies or chromosomal abnormalities.

RESULTS

A total of 158 patients were diagnosed with single-ventricle cardiac defects during the study period. Of those patients, 37 (23.4%) underwent termination of pregnancy, 113 (71.5%) delivered, and 8 (5.1%) had an intrauterine fetal demise. Gestational age at diagnosis and race were significant predictors of the termination decision. The median gestational age at diagnosis was earlier in the termination of pregnancy group (20.4 vs 23.6 weeks; P<.001). Pregnancies complicated by single-ventricle cardiac defects diagnosed in early gestation (11 0/7 to 14 5/7 weeks of gestation) were more likely to be terminated than pregnancies complicated by single-ventricle cardiac defects diagnosed in middle gestation (15 0/7 to 27 5/7 weeks of gestation) and late gestation (≥28 weeks of gestation) (54.2% vs 23.2% and 2.9%; P<.001). Earlier gestational age at diagnosis was correlated with earlier gestational age at termination (r=0.92; P<.001).

CONCLUSION

Termination of pregnancy was more common when the single-ventricle cardiac defect was diagnosed earlier in pregnancy. This could be explained by the fact that early diagnoses allow parents to make deliberate and informed decisions.

Impact of Ventricular Dominance on Long-Term Fontan Outcomes: A 25-year Single-institution Study

BACKGROUND

The long-term impact of ventricular dominance on Fontan outcomes is controversial. This study examined this issue in a 25-year cohort.

METHODS

Patients undergoing the Fontan operation at a single institution (Duke University Medical Center, Durham, NC) from October 1998 to February 2022 were reviewed. Primary outcomes were transplant-free survival and Fontan failure (death, heart transplantation, takedown, protein-losing enteropathy, or plastic bronchitis). Secondary outcomes included hospital and intensive care lengths of stay. Kaplan-Meier methodology compared outcomes by ventricular dominance. Multiphase parametric risk hazard analysis identified risk factors for primary outcomes.

RESULTS

There were 195 patients (104 right ventricular dominant) included in the study. Baseline characteristics were comparable. Perioperative survival was similar (right ventricular dominant, 98%; non-right ventricular dominant, 100%; P = .51). The proportion of patients experiencing death or heart transplantation was 8.7%, and the rate of Fontan failure was 11.8% during a median follow-up of 4.5 years (interquartile range, 0.3-9.8 years). Right ventricular-dominant patients had reduced transplant-free survival (10-year estimates: 80% [95% CI, 70%-91%] vs 92% [95% CI, 83%-100%]; P = .04) and freedom from Fontan failure (73% [95% CI, 62%-86%] vs 92% [95% CI, 83%-100%]; P = .04). Multiphase hazard modeling resolved 2 risk phases. The early phase spanned from surgery to approximately 6 months afterward. The late phase spanned from approximately 6 months after surgery onward. In multivariable analysis, right ventricular dominance was an independent risk factor for death or heart transplantation (parameter estimate, 1.3 ± 0.6; P = .04) and Fontan failure (1.1 ± 0.5; P = .04) during the second phase, with no significant first-phase risk factors.

CONCLUSIONS

Right ventricular dominance was associated with long-term complications after Fontan procedures, including mortality, heart transplantation, and Fontan failure. This cohort may benefit from heightened surveillance in a multidisciplinary Fontan clinic after the perioperative period.

Comparative Metabolomics in Single Ventricle Patients after Fontan Palliation: A Strong Case for a Targeted Metabolic Therapy

Most studies on single ventricle (SV) circulation take a physiological or anatomical approach. Although there is a tight coupling between cardiac contractility and metabolism, the metabolic perspective on this patient population is very recent. Early findings point to major metabolic disturbances, with both impaired glucose and fatty acid oxidation in the cardiomyocytes. Additionally, Fontan patients have systemic metabolic derangements such as abnormal glucose metabolism and hypocholesterolemia. Our literature review compares the metabolism of patients with a SV circulation after Fontan palliation with that of patients with a healthy biventricular (BV) heart, or different subtypes of a failing BV heart, by Pubmed review of the literature on cardiac metabolism, Fontan failure, heart failure (HF), ketosis, metabolism published in English from 1939 to 2023. Early evidence demonstrates that SV circulation is not only a hemodynamic burden requiring staged palliation, but also a metabolic issue with alterations similar to what is known for HF in a BV circulation. Alterations of fatty acid and glucose oxidation were found, resulting in metabolic instability and impaired energy production. As reported for patients with BV HF, stimulating ketone oxidation may be an effective treatment strategy for HF in these patients. Few but promising clinical trials have been conducted thus far to evaluate therapeutic ketosis with HF using a variety of instruments, including ketogenic diet, ketone esters, and sodium-glucose co-transporter-2 (SGLT2) inhibitors. An initial trial on a small cohort demonstrated favorable outcomes for Fontan patients treated with SGLT2 inhibitors. Therapeutic ketosis is worth considering in the treatment of Fontan patients, as ketones positively affect not only the myocardial energy metabolism, but also the global Fontan physiopathology. Induced ketosis seems promising as a concerted therapeutic strategy.