Incremental Detection of Severe Congenital Heart Disease by Fetal Echocardiography Following a Normal Second Trimester Ultrasound Scan in Québec, Canada

Abstract

BACKGROUND: The benefit of fetal echocardiograms (FE) to detect severe congenital heart diseases (SCHD) in the setting of a normal second-trimester ultrasound is unclear. We aimed to assess whether the increase in SCHD detection rates when FE are performed for risk factors in the setting of a normal ultrasound was clinically significant to justify the resources needed. METHODS: This is a multicenter, population-based, retrospective cohort study, including all singleton pregnancies and offspring in Quebec (Canada) between 2007 and 2015. Administrative health care data were linked with FE clinical data to gather information on prenatal diagnosis of CHD, indications for FE, outcomes of pregnancy and offspring, postnatal diagnosis of CHD, cardiac interventions, and causes of death. The difference between the sensitivity to detect SCHD with and without FE for risk factors was calculated using generalized estimating equations with a noninferiority margin of 5 percentage points. RESULTS: A total of 688 247 singleton pregnancies were included, of which 30 263 had at least one FE. There were 1564 SCHD, including 1071 that were detected prenatally (68.5%). There were 12 210 FE performed for risk factors in the setting of a normal second-trimester ultrasound, which led to the detection of 49 additional cases of SCHD over 8 years. FE referrals for risk factors increased sensitivity by 3.1 percentage points (95% CI, 2.3–4.0; P <0.0001 for noninferiority). CONCLUSIONS: In the setting of a normal second-trimester ultrasound, adding a FE for risk factors offered low incremental value to the detection rate of SCHD in singleton pregnancies. The current ratio of clinical gains versus the FE resources needed to screen for SCHD in singleton pregnancies with isolated risk factors does not seem favorable. Further studies should evaluate whether these resources could be better allocated to increase SCHD sensitivity at the ultrasound level, and to help decrease heterogeneity between regions, institutions and operators.

The Quebec Congenital Heart Disease Registry: A Model of Prospective Databank to Facilitate Research in Congenital Cardiology

“…Since its inception, we have successfully linked the patients in the registry with cohorts of patients with CHD that were constituted in parallel of the registry development. These patients were included in the TRIVIA study (cohort of tetralogy of Fallot), 17 , 18 , 19 the FREQUENCY study (cohort of mother-infant pairs for prenatal CHD screening), 20 , 21 and a study on aortic dilatation in the context of a bicuspid aortic valve. 22 The registry has also served as the basis for patient identification and linkage for other ongoing studies ( Table 3 ).…”

“…Secondly, there exists an increasingly strong culture of collaboration between Canadian investigators and institutions in paediatric and congenital cardiology. 11 Thirdly, the Canadian research ecosystem has specific expertise in leveraging the valuable population-based data contained in health care administrative databanks, 28 , 29 in performing linkage of clinical and administrative data for various sources, 17 , 19 , 21 and in providing data infrastructure to facilitate data access without compromising security and confidentiality. 11 Our study provides evidence that development of well-integrated collaborative approaches can improve CHD research in Canada.…”

The Utility of Screening Fetal Echocardiograms Following Normal Level II Ultrasounds in Fetuses with Maternal Congenital Heart Disease

“…These previous studies have noted an approximately 2–3% missed CHD diagnosis rate on the second-trimester screening ultrasound when compared to an F-echo in the current era [ 13 , 18 ]. The possibility of a missed critical CHD when there was a prior normal second-trimester screening ultrasound was < 0.5% in large population studies [ 13 , 19 , 20 ]. The estimated number of F-echo needed to be performed to detect a missed critical CHD ranged from 249 to 750 [ 13 , 20 ].…”

Reply

“…In their commentary, Drs Jiang and Li also argued that fetal echocardiography should be offered to all pregnancies complicated by maternal diabetes. We respect this view and suggest that individual health services should decide on a suitable strategy, largely based on (i) the availability of resources pertaining to fetal echocardiography and (ii) the local rate of detection of mCHD on routine second‐trimester ultrasound 3 . Only if the detection rate of mCHD on second‐trimester ultrasound is zero would 46.2% of mCHD cases be missed, as Drs Jiang and Li asserted.…”