8 The utility of exercise-stress echocardiography for pre-pregnancy risk stratification in patients with left heart obstruction

Abstract

<h3>Introduction</h3> All women with cardiac disease wishing to embark on pregnancy require appropriate pre-conception counselling. A variety of risk stratification tools (mWHO, CARPREG II, ZAHARA) have been proposed to inform shared-decision making and positively influence downstream management. Although consensus guidelines recommend pre-pregnancy exercise testing for all patients with known heart disease, thus far exercise stress echocardiography (ESE) has not been routinely advised. There is, however, potential for SE to provide complementary information among patients with left heart obstruction, which confers a high risk of maternal cardiovascular (CV) complications. We sought to determine the relative value of ESE versus exercise ECG testing for the prediction of adverse maternal CV events in patients with left heart obstruction. <h3>Methods</h3> This was a retrospective observational cohort study; an electronic database search identified 620 patients referred for ESE by cardiologists with expertise in pregnancy, from January 2010 to July 2021 (Figure 1). Left heart obstruction patients who conceived were included in analysis (n=44, age 28±6 y). Baseline demographics were recorded and for each pregnancy, mWHO, CARPREG II and ZAHARA risk scores were calculated. Echocardiography procedures were performed by experienced operators (iE33 or EPIC, Philips Healthcare, Andover, Massachusetts) Patients underwent semi-recumbent bicycle ergometer exercise stress using a WHO25 protocol. An abnormal ESE was defined by the occurrence of: increase in AV mean gradient &gt;20 mmHg, increase in LVOT gradient to &gt;50 mmHg, absence of left ventricular contractile reserve, new dynamic severe MR, PASP &gt;60 mmHg or new wall motion abnormality. An abnormal exercise ECG test was defined by the occurrence of chest pain, ST depression ≥2 mm, a fall in systolic BP or rise &lt;20 mmHg, ventricular arrhythmia or METs &lt;4. The occurrence of pre-conception interventions, and post-conception adverse maternal CV and obstetric events were recorded. Follow up was terminated at 6 months post-partum. <h3>Results</h3> At baseline, out of the total of 44 patients, 24 had at least mild congenital aortic stenosis, 8 had undergone previous aortic valve replacement, and 12 had hypertrophic cardiomyopathy. Twenty-three patients (52%) had an abnormal ESE and 21 patients (48%) had an abnormal exercise ECG test. ESE helped guide 3 pre-conception aortic valve replacements and 1 medical termination. In total, there were 7 adverse maternal CV events (16%) and 10 adverse obstetric events (23%). Prior cardiac medication (p=0.031) and multiple cardiac lesions (p=0.037) were associated with adverse maternal CV events. Of those with abnormal ESE, 5 (22%) patients suffered an adverse maternal CV event, one of which had a normal exercise ECG test. Patients with abnormal ESE accounted for 71% of all adverse maternal CV events (RR= 2.1, 95% CI: 0.5–9.6, p=0.4) and 50% of obstetric events (RR= 0.8, 95% CI: 0.3–2.5, p=1.0). The abnormal exercise ECG group accounted for 57% of adverse maternal CV events (RR=1.2, 95% CI: 0.3, 4.8), p=0.6) and 50% of obstetric events (RR= 0.91, 95% CI: 0.3–2.7, p= 1.0). Of the available risk scores, on ROC analysis, a mWHO class of III-IV was the strongest predictor of CV events (AUC= 0.77, RR: 9.7, 95% CI: 2.2–42.2, P= 0.01). <h3>Conclusion</h3> Patients with abnormal ESE results were twice as likely to suffer an adverse maternal CV event. Abnormal ESE had a stronger association with the occurrence of adverse maternal CV events than exercise ECG testing. These results suggest that ESE provides additive prognostic information among high-risk patients with left heart obstruction. <h3>Conflict of Interest</h3> N/A