Editorials
Cardiovascular Events in Pregnancy With Hypertrophic Cardiomyopathy
2014 Volume 78 Issue 10 Pages 2386-2387
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2014 Volume 78 Issue 10 Pages 2386-2387
Cardiomyopathy during pregnancy is uncommon but potentially life-threatening, accounting for up to 11% of maternal deaths. Peripartum cardiomyopathy (PPCM) is diagnosed in women without a history of heart disease 1 month before delivery or within 5 months postpartum. The EURObservational Research Programme has allowed a comparison of women from around the world, from different ethnic backgrounds, presenting with PPCM and are reporting on their 6- and 12-month outcomes.1 Approximately half of all women will have full myocardial recovery within 6 months of diagnosis, but complications such as severe heart failure or death are not rare. In contrast, women with preexisting cardiomyopathy, such as dilated or hypertrophic cardiomyopathy (HCM), have not been fully evaluated. Patients with a preexisting cardiomyopathy followed closely during pregnancy often tolerate pregnancy and delivery. Risk factors for adverse outcomes include functional status at baseline, severity of systolic dysfunction or outflow tract gradient, or history of prior cardiac event, such as arrhythmia or stroke. The level of B-type natriuretic peptide can be used to risk stratify women for adverse events.2–8
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In this issue of the Journal, Tanaka et al report on the first study in Japan to investigate the cardiovascular events occurring during pregnancy in women with HCM.9 This is an important clinical study providing initial information on cardiovascular events during pregnancy in Japanese HCM patients. The authors clarified that the cardiovascular events occurred in more than half of pregnancies complicated with HCM, and the arrhythmia is the most common cardiovascular event. Their new findings were the medication before pregnancy and that higher CARPREG score and ZAHARA score were risk factors of cardiovascular events during those pregnancies. The CARPREG score is a contemporary assessment of maternal and neonatal risk associated with pregnancy in women with heart disease, and the ZAHARA score is the modified risk score for cardiac complications during completed pregnancies in women with congenital heart disease. Consideration of the timing of cardiovascular events during pregnancy included in this analysis has not been reported before. The authors suggested that cardiovascular events are most likely to occur in the early stage of pregnancy, around 30 gestational weeks, or postpartum. Therefore, strict control is especially necessary in these 3 peak periods of onset.
Their findings are compatible with the profound physiological changes occurring in the cardiovascular system, starting early in the first trimester (Table).3,10 Maternal blood volume increases by 40%, resulting in a 30–50% increase in cardiac output, peaking at approximately 24 weeks of gestation. Vasodilation occurring early in pregnancy because of hormonal influences, and a marked decrease in systemic vascular resistance because of remodeling of placental vessels result in a lowering of the blood pressure by approximately 10 mmHg, returning to prepregnancy levels by term. In labor, stroke volume is increased because of increased venous return resulting from uterine contractions. Finally, after delivery there is an increase in cardiac output that depends on the blood loss during labor and auto-transfusion directly after delivery as a result of uterus contraction. All cardiovascular parameters gradually return to prepregnancy values a few weeks after delivery.
| Hemodynamic parameter | Clinical implication | Findings | |
|---|---|---|---|
| Blood flow | ↑ | · Nasal bleeding · Serum creatinine lower |
· Bounding/collapsing pulse · Prominent non-displaced apical pulse |
| Blood volume | ↑ | · Physiological anemia· High risk of heart failure | · Ejection systolic murmur · Loud first heart sound |
| SVR | ↓ | · Risk of maternal-fetal compromise in patient with fixed CO | · Third heart sound · Venous hum |
| SV | ↑ | · Sinus tachycardia towards end of Pregnancy | · Relative sinus tachycardia (10–20 beats/min) · Ectopic beats |
| CO | ↑ | · Peripheral edema | |
| HR | ↑ | · Warm/erythematous extremities | |
| BP | ↓ | · Elevated JVP in late pregnancy | |
| Pulmonary CWP | ↔ | · Susceptibility to pulmonary edema | |
| CVP | ↔ | ||
| Oxygen consumption | ↑ | · Tendency to ischemia | |
BP, blood pressure; CO, cardiac output; CVP, central venous pressure; CWP, capillary wedge pressure; HR, heart rate; JVP, jugular venous pressure; SV, stroke volume; SVR, systemic vascular resistance.Adapted with permission from Carlin A et al.10
Many problems during pregnancy in women with cardiovascular disease are related to these dynamic physiological changes in the cardiovascular system. Pregnant women with cardiomyopathy should be followed closely by a multidisciplinary team comprising obstetricians, neonatologists, cardiologists, and anesthesiologists.
