SCAD Readmissions Common After Acute MI, Especially in Young Women

After hospitalization for acute MI, patients with spontaneous coronary artery dissection (SCAD) have higher rates of rehospitalization within 30 days than those without SCAD, with 80% of those readmissions being cardiac in nature, numbers from the Nationwide Readmissions Database show.

Of 2.6 million acute MI patients included in the analysis, 1,386 had SCAD (0.052%). At 30 days, SCAD patients were significantly more likely than non-SCAD patients to be readmitted (12.3% vs 9.9%; P = 0.022).

“SCAD is relatively infrequent, but this large database is the first look at identifying who is at risk and what happens to them,” said senior study author Samir R. Kapadia, MD (Cleveland Clinic Foundation, Ohio), in an interview with TCTMD. “What we found confirms that these patients are mostly young and mostly women.” The average age of SCAD patients was 48 years (versus 67 years of age for the entire acute MI cohort), with women making up 71% of the SCAD group.

Kapadia admitted he was a bit surprised to see the 12.3% figure for SCAD readmissions. “The readmission rate is high,” he noted. “Also, from what we can see in this database, they seem to be readmitted just after discharge.” The median time from discharge to readmission for the SCAD group was just 8 days.

What we found confirms that these patients are mostly young and mostly women. Samir Kapadia

In an editorial accompanying the study, Fernando Alfonso, MD, PhD (Hospital Universitario de La Princesa, Madrid, Spain), and colleagues say it would appear to support keeping acute MI patients with SCAD hospitalized longer during the index hospitalization. The median length of stay for the entire cohort was 3 days.

“Currently, however, identification of patients at higher risk for SCAD extension or recurrences remains elusive,” they note. “Moreover, we should humbly recognize that, due to the lack of randomized clinical trials, evidence-based treatments to prevent recurrences are lacking. We do not know the best antithrombotic regimen, or whether this should be customized according to clinical presentation (ie, intramural hematoma versus communicating dissection) or its optimal duration.”

To TCTMD, Kapadia agreed.

“It can be hard to know when it is safe to discharge, even when we feel comfortable doing so,” he said, adding that it is important to get the word out to patients, nurses, and first responders that post-MI patients, especially young women, should not ignore cardiac symptoms. During this current pandemic of COVID-19, when hospitals are reporting unprecedented declines in STEMI presentations, Kapadia said the message to not ignore symptoms and to contact medical help immediately is especially crucial.

Younger, Female, and Healthier

For the study, investigators led by Mohamed M. Gad, MD (Cleveland Clinic Foundation, Ohio), analyzed 30-day readmission for 2,654,087 acute MI patients who were treated between 2010 and 2015. In addition to being more likely to be young and female, SCAD patients were generally healthier, having a lower prevalence of NSTEMI, CABG, and many traditional cardiovascular risk factors.

In both men and women with SCAD, those with STEMI had higher readmission rates than those with NSTEMI (15.3% vs 9.9%; P = 0.003). Additionally, patients who underwent PCI at the index admission had higher rates of readmission than those who did not (15.5% vs 8.7%; P < 0.0001). However, in further analysis, the association between PCI and readmission was significant only among those with SCAD and NSTEMI. In the non-SCAD group, PCI was not associated with a higher rate of readmission among those with NSTEMI, and was associated with a much lower readmission rate in those with STEMI (6.5% vs 13.2%; P < 0.0001).

The researchers also found that that 80% of SCAD readmissions were due to cardiac causes, primarily recurrent MI, followed by chest pain and arrhythmia. More than half of the readmissions occurred in the first 2 days after discharge.

A diagnosis of SCAD in the index hospitalization was an independent predictor of readmission within 30 days (OR 1.19; 95% CI 1.01-1.4). Prior MI, renal failure, heart failure, and chronic obstructive pulmonary disease were among the other predictors.

Alfonso and colleagues note several limitations of the study, including the fact that only readmissions occurring in the same state as the index admission could be analyzed, that potentially relevant clinical and angiographic variables that may have prognostic implications were not captured, and that potential readmission triggers such as physical or physiological stress and discontinuation of medications were not analyzed. They also say it may be useful to know “whether readmissions concentrated in patients with early versus late hospital discharge following the index diagnosis.”

For the time being, SCAD is a “obscure landscape, with major gaps in scientific knowledge,” the editorialists say, and as such should be a focus of future studies.

“Prospective collaborative research efforts, ideally nationwide or international are desperately needed to improve the short- and long-term management and, hopefully, the prognosis of SCAD patients,” they conclude.