Pulmonary Hypertension and Pregnancy Outcomes: Insights From the National Inpatient Sample

Abstract

Background: Pregnant women with pulmonary hypertension (PH) are at risk for adverse cardiac outcomes, particularly at the time of labor and delivery. The purpose of this study is to define the impact of PH on pregnancy outcomes and the risk of major adverse cardiac events (MACE).

Methods and results: The National Inpatient Sample was screened for hospital admissions of women delivering during the years 2003 to 2012. The primary outcome was MACE, a composite of death, cardiac arrest, cardiogenic shock, myocardial infarction, respiratory failure, arrhythmia, stroke, and embolic event. Data on 1519 patients with PH and 6 757 582 without heart disease or PH were available. There were 59.6% with isolated PH; 10.7% with PH and congenital heart disease; 18.1% with PH and valvular heart disease; 3% with PH and valvular heart disease and congenital heart disease; 6.6% PH and cardiomyopathy; and 1.9% with PH and cardiomyopathy and valvular heart disease. Compared with women without heart disease or PH, women with PH experienced significantly higher MACE (24.8 versus 0.4%, P<0.0001). Among the subsets of women with PH, the highest MACE was noted in women with the combination of PH and cardiomyopathy and valvular heart disease, and PH and cardiomyopathy, primarily because of heart failure and arrhythmia. Women with PH were significantly more likely to experience eclampsia syndromes, preterm delivery, and intrauterine fetal demise (P<0.0001 for all). PH subtype was significantly associated with MACE in multivariable analysis (P<0.001).

Conclusions: In a contemporary data set of pregnant women in the United States, PH was associated with an increase in MACE during the hospitalization for delivery, with an exceptionally elevated risk among women with associated cardiomyopathy.

Keywords: cardiomyopathy; congenital heart disease; pregnancy; pulmonary hypertension.

Figure 1

Extraction of study population. This figure illustrates the manner in which records were extracted from the NIS data set. After extraction, there was a total of 1519 patients with PH and 6 757 582 patients without heart disease. HCUP NIS does not allow reporting of <10 events in order to protect individuals’ privacy. HCUP indicates Healthcare Cost and Utilization Project; NIS, National Inpatient Sample; PH, pulmonary hypertension.

Figure 2

Prevalence of pregnancy and PH. This figure shows the breakdown of subclasses among the total 1519 patients with PH. CDM indicates cardiomyopathy; CHD, congenital heart disease; PH, pulmonary hypertension; VHD, valvular heart disease.

Figure 3

MACE rates in pregnant women with pulmonary hypertension. This figure compares the MACE rates of women with PH and women without any heart disease, as well as the MACE rates among the PH subclasses. CDM indicates cardiomyopathy; CHD, congenital heart disease; MACE, major adverse cardiac events; PH, pulmonary hypertension; VHD, valvular heart disease.

Figure 4

Multivariable analysis comparing individual predictors of MACE. Multivariable regression analysis was performed for those factors in which P<0.1 in univariate analysis. “PH and CHD” and “Northeast” were used as references for the disease type and hospital region analysis because they exhibited the lowest MACE rates in descriptive statistics. The following variables were independent predictors for MACE: PH and VHD (P=0.024), PH and VHD and CHD (P=0.0076), PH and CDM (P<0.0001), and PH and CDM and VHD (P<0.0001). CDM indicates cardiomyopathy; CHD, congenital heart disease; CI, confidence interval; HTN, hypertension; MACE, major adverse cardiac events; PH, pulmonary hypertension; VHD, valvular heart disease.