Isolated pre-existing ischemic heart disease (IHD) is associated with an increased risk for severe maternal morbidity (SMM) and mortality during delivery hospitalization researchers reported in JACC: Advances.
The retrospective cohort study compared SMM and mortality rates according to the Centers for Disease Control and Prevention (CDC) among pregnant women with pre-existing IHD with those of women with other cardiac lesions based on modified World Health Organization (mWHO) classification. Data were obtained from the Nationwide Readmissions Database (NRD), Healthcare Cost and Utilization Project, and Agency for Healthcare Research and Quality, which included all hospitalizations for 28 states in 2018.
Eligible participants had a delivery hospitalization from October 1, 2015, to December 31, 2018. The primary outcome was a composite of SMM and maternal mortality during the delivery hospitalization, as defined by the CDC.
A total of 6,109,133 unweighted and 11,556,136 weighted delivery hospitalizations (mean [SD] age, 28.7 [5.8] years) were recorded. Among the delivery hospitalizations, 3009 women had a history of pre-existing IHD with no other cardiac diagnosis, 34,742 had mWHO I to II cardiac disease, 27,579 had mWHO II/III to IV cardiac disease, and 11,490,806 had no cardiac disease. The participants who had pre-existing IHD were older and had higher rates of medical comorbidities compared with those without cardiac disease.
The risk for SMM and mortality for patients with pre-existing IHD was higher compared with those who had no cardiac disease or low-risk cardiac disease, but significantly lower vs those with a high-risk cardiac disease, according to unadjusted analyses. Among patients with pre-existing IHD, 6.6% had SMM or mortality vs 1.5% of those without a cardiac disease (unadjusted relative risk [RR] vs no cardiac disease, 4.3; 95% CI, 3.5-5.2), 4.2% of those with mWHO I to II cardiac disease (RR vs no cardiac disease, 2.7; 95% CI, 2.5-2.9), and 23.1% of those with mWHO II/III to IV cardiac disease (RR, 14.9; 95% CI, 14.3-15.6).
In the adjusted analysis, pre-existing IHD alone was associated with an increased risk for SMM and mortality (adjusted RR [aRR], 1.51; 95% CI, 1.19-1.92), nontransfusion SMM and mortality (aRR, 1.60; 95% CI, 1.11-2.30), and cardiac SMM and mortality (aRR, 2.98; 95% CI, 1.75-5.08) compared with having no cardiac disease. The risk for SMM and mortality, nontransfusion SMM and mortality, and cardiac SMM and mortality for IHD alone was most comparable to that of mWHO class I or II cardiac diseases.
Study limitations include the dependence on diagnosis and procedure codes, and that outcomes are limited to the delivery hospitalization. In addition, participants from the NRD are not linked across years, which prevents adjustment for multiple pregnancies. Furthermore, the patients with pre-existing IHD may represent a healthier cohort than may be encountered clinically, and the temporal relationships among the diagnoses of pre-existing IHD, SMM outcomes, and comorbidities were not assessed.
“It is important to communicate to patients that while pregnancy may be considered low risk in the setting of pre-existing IHD, 6.6% of patients with pre-existing IHD alone did experience severe maternal morbidity or death during the delivery hospitalization,” wrote the study authors. “Other medical comorbidities should be factored into discussions regarding the risks of pregnancy.”
Denoble AE, Goldstein SA, Wein LE, Grotegut CA, Federspiel JJ. Impact of pre-existing ischemic heart disease on severe maternal morbidity and mortality during delivery hospitalizations. JACC: Advances. Published online December 14, 2022. doi: https://doi.org/10.1016/j.jacadv.2022.100157