Lifelong burden of small unrepaired atrial septal defect: Results from the Danish National Patient Registry

Lifelong burden of small unrepaired atrial septal defect: Results from the Danish National Patient Registry.

Udholm S, Nyboe C, Karunanithi Z, Christensen AI, Redington A, Nielsen-Kudsk JE, Hjortdal VE.

Int J Cardiol. 2019 May 15;283:101-106. doi: 10.1016/j.ijcard.2019.02.024. Epub 2019 Feb 16.

PMID: 30826194

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Take Home Points

  • An analysis of survival and morbidity of all patients with a small unrepaired ASD listed in the Danish National Patient Registry (DNPR) between 1953 and 2011 compared to the background population.
  • 723 patients were defined as having a small unrepaired ASD in the DNPR.
  • Since the time of diagnosis 182 patients (25%) had died with a mean lifespan of 63 years. Mean age at diagnosis was late in these patients – 53 years.
  • The commonest cause of death was heart failure.
  • Compared to the general population, patients with an ‘insignificant’ unrepaired ASD had a higher burden of chronic disease (27% vs 38%, p=0.005) – particularly lung disease (1% vs 4%).
  • In a select number of patients aged 18-65 years, listed as having a small unrepaired ASD whom underwent TTE (n=153), the ASD had spontaneously closed in 80% (n=123).
  • 6MWT was significantly lower (632+/- 90m) in patients previous diagnosed with an ASD vs calculated reference values (715 +/- 94m, p=0.00001).
  • Further investigation and data collection is required to help explain why morbidity and mortality should be worse in patients with a seemingly ‘low risk’ congenital cardiac anomaly, even when the ASD closes spontaneously.

Commentary from Dr. Damien Cullington (Leeds UK), section editor of ACHD Journal Watch: The Danish National Patient Registry (DNPR) is a remarkable epidemiological feat which has collated complete data on all residents living in Denmark since 1977. It contains information on all inpatient and outpatient hospital contacts in Denmark and diagnoses are made according to ICD definitions. Only patients with ASDs deemed to be ‘insignificant’ i.e. unrepaired, small, and with a Qp:Qs <1.5 were included in the analysis.


Between 2015 and 2018, patients remaining alive and aged 18-65 yrs. with an unrepaired ASD (n=361) were invited to undergo further testing – a questionnaire, TTE, spirometry and 6MWT – only 156 patients were included in this more extensive assessment (Fig 1)


Patients with an ASD

2277 adult patients were listed in the DNPR as having an ASD. Of these, just over two thirds of patients (n=1554) had surgical or device ASD closure. The remainder (n=723) had an unrepaired ASD. It is unclear how patients with seemingly small ASDs were diagnosed – often such patients are completely asymptomatic with few clinical signs on examination. It is inevitable that there are many more patients in the general population with small, ‘innocuous’ ASDs which are still undiscovered.


A quarter of patients with an unrepaired ASD (n=182) died at a mean age of death of 63 years (range 0.2-99.1 years). Of note, the mean age at diagnosis of those patients who died was relatively advanced at 53 +/-27 years old. Nearly half of deaths (n=47) were of cardiac aetiology.

Figure 1. Flowchart of patient inclusion



Echo data (n=153)

On TTE assessment, most ASDs had spontaneously closed and there were only 30 patients who had small, open ASDs. (Fig 2). Patients who still had a small ASD compared to those who had closed spontaneously, had larger right heart dimensions. No differences were seen in ventricular function, estimated filling pressures or estimated pulmonary pressures. The mean age at diagnosis of this patient cohort was 9 years old.



It is not clear from this analysis why patients with seemingly small, innocuous ASDs, even in those which have spontaneously closed have worse survival, more chronic disease, higher levels of anxiety and worse functional capacity. Continued observation and collection of epidemiological data is required. It is not clear if earlier closure of these small ASDs, often viewed as seemingly benign, can avert these adverse outcomes. Patients with even small ASDs should be followed up longer term to check for any clinical deterioration.


Figure 2. Echocardiographic data from selected patients listed in the DNPR as having an unrepaired ASD (n=153) who subsequently had echo. The ASD had spontaneously closed (n=123) vs remainder open (n=30).