Baseline LVEF May Predict Peripartum Cardiomyopathy Recovery, CV Outcomes

Deborah Brauser

August 21, 2015

PITTSBURGH, PA – Although the majority of women with peripartum cardiomyopathy (PPCM) make a full recovery within a year of giving birth and after receiving "conventional heart-failure therapy," those with severe left ventricular (LV) dysfunction and significant remodeling at first visit are at risk for future CV events, suggests new research[1].

Results from the prospective Investigations of Pregnancy Associated Cardiomyopathy (IPAC) study, which included 100 women with PPCM, showed that 91% of participants who had an LVEF >0.30 and left ventricular end-diastolic diameter (LVEDD) <6.0 cm at baseline had a full recovery at the 1-year postpartum follow-up vs 0% of women with both LVEF <0.30 and LVEDD >6 cm at baseline.

A total of 13% of participants experienced a major event or had persistent severe cardiomyopathy at the 1-year follow-up. Black women were especially at risk, with significantly more LV dysfunction at first visit and at 6 and 12 months postpartum, as well as more CV events.

"I was encouraged and pleasantly surprised by the degree of overall recovery we saw," lead author Dr Dennis M McNamara (University of Pittsburgh Medical Center, PA) told heartwire from Medscape. "However, the mortality rate at 1 year was too high at roughly 6%, and a number of women were left with severe cardiomyopathy. So we still have work to do."

Still, McNamara noted that the number-one takeaway is that severity of LV function at presentation, as measured by echocardiogram, "is probably the best clinical predictor we have of how these women will do."

The findings were published in the August 25, 2015 issue of the Journal of the American College of Cardiology.

Rare but Deadly

The researchers note that PPCM affects roughly one in 2000 women in the US. "Given the low prevalence of the disorder, most single-center reports are limited in study number and to being retrospective, and there are minimal prospective data on clinical outcomes of contemporary evidence-based therapy," they write.

"Although [PPCM] is an uncommon complication of pregnancy, it is a major cause of maternal morbidity and mortality. At transplant centers, we see women referred to us with the worst forms of this disorder," added McNamara.

"It is poorly understood, and because of its rarity we felt we needed to get a large group together to be able to investigate what was causing this disease and see how we could better predict who would and would not recover."

In the IPAC study, 100 women (65% white, 30% black; mean age 30 years) with newly diagnosed PPCM, but no history of CVD, were enrolled at 30 US centers between December 2009 and September 2012. Mean LVEF of the study population was 0.35.

Echocardiograms were used to measure LVEF at baseline and at the 6- and 12-month postpartum follow-ups. Beta-blockers were used by 88% of participants, and 81% used ACE inhibitors or angiotensin-receptor blockers.

Event-free survival was defined as "survival without LVAD implantation or cardiac transplantation." Transplantation-free survival did not include LVAD implantation.

At the 6-month follow-up, mean LVEF had risen to 0.51, and was 0.53 at 12 months. An LVEF >0.50 (the criteria for "recovery") was achieved by 72% of women at 1 year. However, 13% had an LVEF <0.35 at the same time point.

Risk factors for having a lower LVEF at 1 year postpartum included having a baseline LVEF <0.30 or LVEDD >6.0 cm or being black (all P <0.001).

Mean baseline LVEF was significantly lower in black vs other participants (0.31 vs 0.36, respectively, P=0.009). Black women also had significantly higher mean diastolic blood pressure (P=0.009) and history of hypertension (P=0.002).

Although improved, LVEFs were significantly lower in black women vs others at 6 months (0.46 vs 0.53, respectively, P=0.006) and 12 months (0.47 vs 0.56, P=0.001). In addition, only 59% had a final LVEF >0.50 (vs 77%).

CV Events

At 1 year, there were four LVAD implantations, four deaths, and one heart transplantation among six study participants, and various cardiac hospitalizations experienced by three others. A total of 26% of black women had some type of CV event or a final LVEF <0.35 vs 8% of other participants (P=0.03).

Overall, there was a 93% event-free survival rate and 95% transplantation-free survival rate at 1 year.

Women with a baseline LVEF >0.30 had significantly greater event-free survival vs women with a baseline LVEF <0.30 (99% vs 82%, P=0.004). There were no significant differences between white and black women for this end point.

Investigators note that although "the overwhelming majority" of study participants recovered, the poor outcomes "remain unacceptably high."

"There remains a great need for more targeted therapies to improve outcomes in those women whose probability of recovery on conventional therapy is diminished," they write, adding that future studies that target those with poor LVEF and greater LV dilation "may permit a better assessment of novel therapeutic interventions."

McNamara reiterated that "the simple clinical tool of a cardiac echo" is extremely valuable. "If a woman, at birth or in the immediate postpartum period, complains of shortness of breath, clinicians should have a low threshold for at least doing a transaortic echo—a simple, noninvasive test that will pick up any cases of cardiomyopathy."

"Landmark Trial"

In an accompanying editorial, Dr Gregg M Lanier (New York Medical College/Westchester Medical Center, Valhalla) notes that this is the largest prospective study of the condition ever conducted[2].

"This . . . is a landmark trial in PPCM because it may pave the way for future treatment studies," he writes. And although many questions still remain, "the multicenter frameworks of this large cohort will likely continue to add new insights into this rare and potentially devastating cardiomyopathy."

To heartwire, Lanier noted that there really haven't been any large advances to understanding the pathophysiology of this rare disease. "Hopefully, this IPAC consortium will allow future explorations into the field."

In the current trial, he noted it's clear that patients with a dilated heart and very low ejection fraction "are at the highest risk of bad outcomes" over the following year.

"Because the majority of these patients have improvement on their own, it's hard to assess the impact of interventions. But if we apply the results of this trial to future studies, maybe we’ll be able to have more robust outcomes and understand whether or not medications have an impact and can change the natural history of the disease," said Lanier.

He added that there are currently no consensus statements for these patients. But results from this and future studies may lead to more specific recommendations in heart-failure guidelines.

"This may allow us to actually say, 'These are the patients that need to be followed closer because they're at higher risk of progression of heart failure and higher risk of death.'"

The study was funded by the National Heart, Lung, and Blood Institute. Study authors and Lanier report no relevant financial relationships.

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