Peripartum cardiomyopathy: Causes, diagnosis, and treatment
ABSTRACTPeripartum cardiomyopathy is a life-threatening condition of unknown cause that occurs in previously healthy women during the peripartum period. It is characterized by left ventricular dysfunction and symptoms of heart failure that can arise in the last trimester of pregnancy or up to 5 months after delivery. We review its possible causes and how to recognize and manage it.
KEY POINTS
- Heightened suspicion is important when a pregnant woman presents with signs of heart failure, because early diagnosis allows proven treatment to be started.
- Standard heart failure therapy should be started in postpartum patients with this disease, using available local protocols.
- Pregnant women should not receive angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or warfarin because of potential teratogenic effects.
- An initial left ventricular end-systolic dimension less than 5.5 cm, a left ventricular ejection fraction greater than 30%, and a low cardiac troponin level may predict a better outcome.
- Subsequent pregnancies carry a high risk of relapse, even in women who have fully recovered left ventricular function.
NATURAL COURSE
In a study of patients with various types of cardiomyopathy, those with peripartum cardiomyopathy had a substantially better prognosis, with a 94% survival rate at 5 years.7
Although various reports have shown that the clinical course of peripartum cardiomyopathy is usually related to the return of heart size to normal within 6 months, it is possible that left ventricular function may continue to recover beyond 6 months, and further studies are needed to determine the reasons for this.54
Elkayam et al36 reported that, of 100 patients with peripartum cardiomyopathy in the United States, at the end of 2 years, 9 had died and 4 had received a heart transplant. However, 54 had recovered normal left ventricular function, and recovery was more likely in those with an ejection fraction greater than 30% at diagnosis. The incidence of gestational hypertension was 43%, and the rate of twin pregnancy was 13%. The rate of cesarean delivery was 40%, compared with the national rate of 30.2%.
In contrast, in 98 patients in Haiti, the death rate was 15.3% during a mean follow-up of 2.2 years, and only about 28% had regained normal left ventricular function at 6 months.5
PROGNOSTIC FACTORS
Troponin T. Hu et al41 reported that the serum cardiac troponin T concentration measured 2 weeks after the onset of peripartum cardiomyopathy correlated inversely with the left ventricular ejection fraction at 6 months. However, the sensitivity was low: a troponin T concentration of more than 0.04 ng/mL predicted persistent left ventricular dysfunction with a sensitivity of only 55%. The specificity was 91%.
QRS duration of 120 ms or more has been identified as a predictor of death. Prolonged QRS duration has been shown to be an independent risk factor for death and sudden death in a large series of patients with ischemic and nonischemic cardiac failure.77
Heart dimensions and ejection fraction had prognostic value in several studies.
Factors predicting normalization of left ventricular function were an initial left ventricular end-systolic dimension of 5.5 cm or less78 and a left ventricular ejection fraction greater than 27%78 or 30%.36
In a retrospective study,79 a fractional shortening of 20% or more and a left ventricular end-diastolic dimension of 6 cm or more at the time of diagnosis increased the risk of persistent left ventricular dysfunction threefold. Other factors at initial assessment associated with lack of recovery were a left ventricular end-diastolic dimension greater than 5.6 cm, left ventricular thrombus, and African American race.6
RISK OF RELAPSE
Even after full recovery of left ventricular function, subsequent pregnancies carry a risk of relapse of peripartum cardiomyopathy. A study in Haiti followed 99 patients, 15 of whom became pregnant again. Eight of the women who became pregnant again experienced worsening heart failure and long-term systolic dysfunction.80
Of six South African women who had New York Heart Association class I symptoms who became pregnant again, two died within 8 weeks of delivery, and the other four continued to have heart failure symptoms.81
In the United States, Elkayam et al82 identified 44 women with peripartum cardiomyopathy who became pregnant again. Of these, 28 had recovered systolic function, with ejection fractions of 50% or higher before becoming pregnant again, and 16 had not. The ejection fraction fell in both groups during the subsequent pregnancy, but in the first group it fell by more than 20% in only 6 (21%), and none died. In contrast, in the second group it fell by more than 20% in 5 (31%), and 3 (19%) died.
Patients who recover normal left ventricular function and have normal left ventricular contractile reserve after dobutamine challenge may undertake another pregnancy safely, but they should be warned of the risk of recurrence even with fully recovered left ventricular function.46,82
Dorbala et al83 performed dobutamine stress echocardiography to measure maximal inotropic contractile reserve in six women presenting with peripartum cardiomyopathy, and it correlated accurately with subsequent recovery of left ventricular function.
Based on these data, our recommendations for further pregnancies are the following:
- If left ventricular function has recovered fully, subsequent pregnancy is not contraindicated, but the patient should be told that, although the risk is low, it is not absent.
- If left ventricular function has recovered partially, perform dobutamine stress echocardiography. If the left ventricular inotropic response to dobutamine is normal, then patients can be counseled as above; if the left ventricular inotropic response to dobutamine is abnormal, then the risk is moderate and pregnancy is not recommended.
- If left ventricular function has not recovered at all, the risk is high, and subsequent pregnancy is not recommended.
