Background

Pulmonary atresia is a birth defect of the heart where the pulmonary valve fails to form. Due to this defect, blood from the right ventricle cannot get directly into the lungs from the pulmonary artery as in a normal heart. [1] In newborns with pulmonary atresia, the blood bypasses the unformed pulmonary valve through openings between the upper chambers of the heart (patent foramen ovale) and from the aorta to the pulmonary artery (ductus arteriosus) that ordinarily exist during gestation. These openings normally close shortly after birth but are critical for the survival of patients with pulmonary atresia. [1] There are two types of pulmonary atresia - 1) pulmonary atresia with a ventricular septal defect, or 2) pulmonary atresia without a ventricular septal defect (intact septum). In pulmonary atresia without a ventricular septal defect, the right ventricle receives little blood flow, causing it to be underdeveloped at birth. [3] With pulmonary atresia with ventricular septal defect, the defect allows blood to flow to the right ventricle, which simulates more normal development of the ventricle. [1] Pulmonary atresia can be diagnosed before birth by ultrasound, or soon after birth via echocardiogram. [2] Typical treatments for this condition are medication (prostaglandin) to maintain the ductus arteriosus, balloon valvotomy to open the pulmonary valve, ductal stent placement to keep this connection open to allow blood flow to the lungs, or a systemic-to-pulmonary artery shunt that connects one of the arteries to the pulmonary artery [4] Infants with pulmonary atresia often need surgery or other procedures soon after birth, therefore, this defect is considered a critical congenital heart defect (CCHD). Common signs and symptoms for this defect are cyanosis (blue skin tone) which can be detected by pulse oximetry, shortness of breath, difficulty feeding, and heart murmur. [2]

Epidemiology

Alaska Birth Defects Registry (ABDR) registers birth defects as reported from health care providers using International Classification of Disease (ICD) billing codes. The use of these ICD codes can lead to misclassification of diagnosed conditions. Prior to this report, all prevalence estimates were based on the number of unique children reported to ABDR with an ICD code representing a specified condition regardless of case confirmation status.

The estimates in this report were derived by conducting medical record review and case confirmation of all reported cases between 2007 and 2018. The confirmation probability derived from this time period is used to develop informed estimates of the defect prevalence beyond 2018. See Defect prevalence calculation.

For explanations of table columns see Column descriptions.

Prevalence

Pulmonary atresia occurs in about 1.4 out of every 10,000 live births in the United States. This results in about 550 babies diagnosed with pulmonary atresia nationally each year.[1]

In Alaska, during 2007-2017, the prevalence of Pulmonary atresia was 1.2 per 10,000 live births.
Reports Defects Births Prevalence (95% CI)
Total 20 14.6 123630 1.2 (0.7, 1.9)
Notes: 95% CI = 95% Confidence Interval

Trend

Prevalence per 10,000 births of Pulmonary atresia during 2007-2017 by five-year moving averages, with 95% confidence interval band and Poisson estimated fitted line.
Reports Defects Births Prevalence (95% CI) Predicted Prevalence†
2007-2011 2.3 1.7 11404.7 1.5 (0.3, 5.3) 1.7
2008-2012 2.0 1.5 11354.0 1.3 (0.2, 4.8) 1.4
2009-2013 2.3 1.7 11349.0 1.5 (0.3, 5.4) 1.1
2010-2014 1.7 1.2 11334.7 1.1 (0.1, 4.4) 0.9
2011-2015 1.0 0.7 11377.3 0.6 (0.1, 3.8) 0.7
2012-2016 0.7 0.5 11295.0 0.4 (0.0, 3.3) 0.6
2013-2017 0.7 0.5 10979.7 0.5 (0.0, 3.4) 0.5
Notes: Each row is based on five-year moving averages; Prevalence reported per 10,000 live births; 95% CI=95% Confidence Interval

† Estimated rate based on Poisson model
The p-value test for trend detected a significant decrease in the number of live births with Pulmonary atresia during 2007-2017. See p-value estimate
Estimate Std. Error t value Pr(>|t|)
-0.22017 0.04899 -4.49403 0.00643

Regional Distribution

Distribution of Pulmonary atresia in Alaska by Public Health Region of maternal residence at the time of birth. A description of regional breakdowns can be found here. Data suppressed for # of reports < 6.
Reports Defects Births Prevalence (95% CI)
Anchorage 9 6.6 50455 1.3 (0.6, 2.6)
Gulf Coast - - 7725 -
Interior - - 22487 -
Mat-Su - - 14937 -
Northern - - 8520 -
Southeast - - 7625 -
Southwest - - 11881 -
Notes:Prevalence reported per 10,000 live births; Data suppressed for # of reports < 6; 95% CI = 95% Confidence Interval

Demographics

Some subgroups may be more at risk for having a baby with Pulmonary atresia. This section provides the descriptive epidemiology of specified maternal, birth, and child characteristics identified from the birth certificate.

Reports Defects Births Prevalence (95% CI)
Sex
  Female 7 5.1 59998 0.8 (0.4, 1.9)
  Male 13 9.5 63632 1.5 (0.8, 2.7)
Birth weight (grams)
  <2500 6 4.4 7231 6.1 (2.2, 14.2)
  2500+ 14 10.2 116215 0.9 (0.5, 1.6)
Maternal age
  12-19 - - 9156 -
  20-24 6 4.4 32872 1.3 (0.5, 3.1)
  25-29 7 5.1 37743 1.4 (0.6, 3.1)
  30-34 - - 28152 -
  35-39 - - 12614 -
  40+ - - 3064 -
Maternal race
  Alaska Native/American Indian 6 4.4 31560 1.4 (0.5, 3.2)
  Asian/Pacific Islander - - 11810 -
  Black - - 5081 -
  White 9 6.6 73595 0.9 (0.4, 1.8)
Maternal education (years)
  <12 - - 11929 -
  12 - - 43162 1.5 (0.7, 3.0)
  12+ - - 65105 0.7 (0.2, 1.6)
Marital status
  Married 6 4.4 78396 0.6 (0.2, 1.3)
  Unmarried 14 10.2 44625 2.3 (1.2, 4.1)
Maternal smoking use
  Reported smoking 7 5.1 16817 3.0 (1.3, 6.9)
  Reported not smoking 11 8 104707 0.8 (0.4, 1.5)
Medicaid (mother or child)
  Medicaid - - 62666 1.8 (0.9, 2.9)
  non-Medicaid - - 60839 -
Father on birth certificate
  None - - 6328 -
  Present - - 117302 1.1 (0.6, 1.8)
Notes: Prevalence reported per 10,000 live births; Data suppressed for # of reports < 6; 95% CI = 95% Confidence Interval

Technical notes

Column descriptions

# Reports: Unless otherwise noted, the number of unique reports of the defect received by ABDR during the specified birth year(s). Each report represents a unique child with the specified defect.

# Defects: The estimated true number of reports that are diagnosed defects based on medical record review and case confirmation.

# Births: The number of live births among Alaskan residents that occurred in Alaska during the specified birth year(s).

Prevalence (95% CI): The estimated diagnosed prevalence of the condition and corresponding 95% Confidence Interval. (For information on how the defect prevalence was estimated see below).

Defect prevalence calculation

The estimated defect prevalence was calculated using a Bayesian approach based on the reported prevalence, PPV and 1-NPV (see formula below).

Through medical records review and case confirmation of a random sample of reported cases, the defect prevalence is calculated as:

\[PPV (Positive Predictive Value) = p(defect|report)\] \[NPV (Negative Predictive Value) = p(\overline{defect}|\overline{report})\]

\[p(defect) \approx [p(report)\cdot PPV]+[p(\overline{report})\cdot (1-NPV)]\]

Defect prevalence estimates are a more accurate estimation of the actual diagnosed prevalance of birth defects compared to the reported prevalance estimates in Alaska. ABDR obtains reports from medical providers using International Classification of Disease (ICD) codes that are extracted from individual systems which when aggregated may not reflect true diagnostics. Caution should be used when interpreting and comparing the reported prevalence estimates with national estimates.

See Data analysis methods for more information.

P-value estimate

To evaluate the trend over time and account for under/over-dispersion we constructed a quasi-Poisson regression model. This model assumes the variance is a linear function of the mean and models the estimated number of annual defects by year with a natural log (ln) offset of the annual births. P-values < 0.05 are considered significant, which indicates that the predicted slope is significantly different from a slope of zero.

Data suppression

For region and demographic data tables, values are suppressed based on the number of reports received during the observation period. Counts less than 6 are suppressed (as indicated by ‘-’ in the table). For regions or demographics with only one cell count suppressed a second is suppressed to eliminate the ability to back-calculate the estimate.

References

[1] Congenital Heart Defects - Facts about Pulmonary Atresia | CDC. (2019). Retrieved 20 March 2021, from https://www.cdc.gov/ncbddd/heartdefects/pulmonaryatresia.html

[2] Pulmonary Atresia | Children’s Hospital of Philadelphia. (2021). Retrieved 20 March 2021, from https://www.chop.edu/conditions-diseases/pulmonary-atresia

[3] Pulmonary Atresia | Boston Children’s Hospital. (2021). Retrieved 20 March 2021, from https://www.childrenshospital.org/conditions-and-treatments/conditions/p/pulmonary-atresia

[4] Pulmonary atresia with intact ventricular septum - Overview - Mayo Clinic. (2021). Retrieved 20 March 2021, from https://www.mayoclinic.org/diseases-conditions/pulmonary-atresia-intact-ventricular-septum/cdc-20396714

Authorship

Maternal and Child Health (MCH) senior epidemiologist Dr. Jared Parrish, PhD conceived of the presented analysis. Alaska Birth Defects Registry program manager and epidemiologist Chris Barnett, MS MPH and Dr. Jared Parrish, PhD developed the theory and performed the computations. Research analysts Monica Mills and Jordyn Lord managed the project and data storage. Pediatric cardiologist Dr. James Christiansen, MD performed defect confirmations and provided medical consultation. All authors discussed the results and contributed to the final report.

Suggested Citation

State of Alaska Department of Health and Social Services, Division of Public Health, Section of Women’s, Children’s, and Family Health. Alaska Birth Defects Registry Condition Report: Pulmonary Atresia, Alaska, 2007-2017. Updated June 22, 2021. Available at: http://rpubs.com/AK_ABDR/pulmonary_atresia/07_17.

Contact

Alaska Birth Defects Registry (ABDR)
3601 C Street, Suite 358
Anchorage, AK 99503
(907) 269-3400 phone
(907) 754-3529 fax

Updated: June 22, 2021
Code source: R:\ABDR\Analysis_New\ABDR_CASECONF\cond_reports\Published_reports\Pulmonary_Atresia07_17.Rmd