“These data identify the need for us to continue working to identify barriers in terms of diagnosis, management, and technological innovations for women in cardiogenic shock to resolve these issues and improve outcomes,” the senior author of the study, Navin Kapur, MD, Tufts Medical Center, Boston, said in an interview.
The study is said to be the one of the largest contemporary analyses of real-world registry data on the characteristics and outcomes of women in comparison with men with cardiogenic shock.
It showed sex-specific differences in outcomes that were primarily driven by differences in heart failure–related cardiogenic shock. Women with heart failure–related cardiogenic shock had more severe cardiogenic shock, worse survival at discharge, and more vascular complications than men. Outcomes in cardiogenic shock related to MI were similar for men and women.
The study, which will be presented at the upcoming annual meeting of the American Heart Association, was published online in JACC: Heart Failure.
Dr. Kapur founded the Cardiogenic Shock Working Group in 2017 to collect quality data on the condition.
“We realized our patients were dying, and we didn’t have enough data on how best to manage them. So, we started this registry, and now have detailed data on close to 9,000 patients with cardiogenic shock from 45 hospitals in the U.S., Mexico, Australia, and Japan,” he explained.
“The primary goal is to try to investigate the questions related to cardiogenic shock that can inform management, and one of the key questions that came up was differences in how men and women present with cardiogenic shock and what their outcomes may be. This is what we are reporting in this paper,” he added.
Cardiogenic shock is defined as having a low cardiac output most commonly because of MI or an episode of acute heart failure, Dr. Kapur said. Patients with cardiogenic shock are identified by their low blood pressure or hypoperfusion evidenced by clinical exam or biomarkers, such as elevated lactate levels.
“In this analysis, we’re looking at patients presenting with cardiogenic shock, so were not looking at the incidence of the condition in men versus women,” Dr. Kapur noted. “However, we believe that cardiogenic shock is probably more underrepresented in women, who may present with an MI or acute heart failure and may or may not be identified as having low cardiac output states until quite late. The likelihood is that the incidence is similar in men and women, but women are more often undiagnosed.”
For the current study, the authors analyzed data on 5,083 patients with cardiogenic shock in the registry, of whom 1,522 (30%) were women. Compared with men, women had slightly higher body mass index (BMI) and smaller body surface area.
Results showed that women with heart failure–related cardiogenic shock had worse survival at discharge than men (69.9% vs. 74.4%) and a higher rate of refractory shock (SCAI stage E; 26% vs. 21%). Women were also less likely to undergo pulmonary artery catheterization (52.9% vs. 54.6%), heart transplantation (6.5% vs. 10.3%), or left ventricular assist device implantation (7.8% vs. 10%).
Regardless of cardiogenic shock etiology, women had more vascular complications (8.8% vs. 5.7%), bleeding (7.1% vs. 5.2%), and limb ischemia (6.8% vs. 4.5%).
“This analysis is quite revealing. We identified some important distinctions between men and women,” Dr. Kapur commented.
For many patients who present with MI-related cardiogenic shock, many of the baseline characteristics in men and women were quite similar, he said. “But in heart failure–related cardiogenic shock, we saw more differences, with typical comorbidities associated with cardiogenic shock [e.g., diabetes, chronic kidney disease, hypertension] being less common in women than in men. This suggests there may be phenotypic differences as to why women present with heart failure shock versus men.”
Dr. Kapur pointed out that differences in BMI or body surface area between men and women may play into some of the management decision-making.
“Women having a smaller stature may lead to a selection bias where we don’t want to use large-bore pumps or devices because we’re worried about causing complications. We found in the analysis that vascular complications such as bleeding or ischemia of the lower extremity where these devices typically go were more frequent in women,” he noted.
“We also found that women were less likely to receive invasive therapies in general, including pulmonary artery catheters, temporary mechanical support, and heart replacements, such as LVAD or transplants,” he added.
Further results showed that, after propensity score matching, some of the gender differences disappeared, but women continued to have a higher rate of vascular complications (10.4% women vs. 7.4% men).
But Dr. Kapur warned that the propensity-matched analysis had some caveats.
“Essentially what we are doing with propensity matching is creating two populations that are as similar as possible, and this reduced the number of patients in the analysis down to 25% of the original population,” he said. “One of the things we had to match was body surface area, and in doing this, we are taking out one of the most important differences between men and women, and as a result, a lot of the differences in outcomes go away.
“In this respect, propensity matching can be a bit of a double-edge sword,” he added. “I think the non–propensity-matched results are more interesting, as they are more of a reflection of the real world.”
Dr. Kapur concluded that these findings are compelling enough to suggest that there are important differences between women and men with cardiogenic shock in terms of outcomes as well as complication rates.
“Our decision-making around women seems to be different to that around men. I think this paper should start to trigger more awareness of that.”
Dr. Kapur also emphasized the importance of paying attention to vascular complications in women.
“The higher rates of bleeding and limb ischemia issues in women may explain the rationale for being less aggressive with invasive therapies in women,” he said. “But we need to come up with better solutions or technologies so they can be used more effectively in women. This could include adapting technology for smaller vascular sizes, which should lead to better outcome and fewer complications in women.”
He added that further granular data on this issue are needed. “We have very limited datasets in cardiogenic shock. There are few randomized controlled trials, and women are not well represented in such trials. We need to make sure we enroll women in randomized trials.”
Dr. Kapur said more women physicians who treat cardiogenic shock are also required, which would include cardiologists, critical care specialists, cardiac surgeons, and anesthesia personnel.
He pointed out that the two first authors of the current study are women – Van-Khue Ton, MD, Massachusetts General Hospital, Boston, and Manreet Kanwar, MD, Allegheny Health Network, Pittsburgh.
“We worked hard to involve women as principal investigators. They led the effort. These are investigations led by women, on women, to advance the care of women,” he commented.