In Certain SCAD Patients With STEMI, Primary PCI May Be Beneficial

For patients with STEMI secondary to spontaneous coronary artery dissection (SCAD), primary PCI can produce mortality and 30-day readmission rates similar to what’s seen in those treated for atherothrombotic STEMI, Spanish registry data suggest.

Fernando Alfonso, MD (Hospital Universitario de La Princesa, Madrid, Spain), lead author of the study, told TCTMD that the new results, while “good news,” don’t undermine conservative management’s role as the main strategy for treating SCAD.

“The prognosis in [SCAD] patients treated conservatively is very good,” he explained. Many will stabilize clinically after the acute ischemic insult and see their vessel wall heal on its own. Also, with revascularization, complications can occur, he added. “If we intervene on these patients, the possibility of causing further trauma [to] these already disrupted arteries increases. So, there are poorer procedure-related results, and also poorer outcomes.”

But for some SCAD patients with STEMI, it makes sense to take quick action and open the affected artery, said Alfonso.

“This study is interesting because, though it’s a retrospective study, it’s from a large Spanish National Health System data set. . . . This is an all-comers population without really any inclusion or exclusion criteria—a real-world population,” said Poonam Velagapudi, MD (University of Nebraska Medical Center, Omaha), who co-wrote an accompanying editorial with Ajay J. Kirtane, MD (NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY), and Jacqueline Saw, MD (Vancouver General Hospital, Canada).

The lack of significant difference for either in-hospital mortality or 30-day readmission rates “shows that probably the interventional cardiologists in that region are actually selecting the right kind of patients [in whom] to do PCI. That’s really good to know,” given that earlier observational studies have not been as encouraging, she said in an interview with TCTMD.

The results were published online recently in JACC: Cardiovascular Interventions.

In-Hospital Mortality and 30-Day Readmission

Alfonso and colleagues gathered data from the Spanish National Health System on 65,958 primary PCIs performed between 2016 and 2020. Just 315 (0.5%) of these cases were in patients with SCAD.

Compared with patients who underwent primary PCI in the absence of SCAD, those in the SCAD subgroup tended to be younger (mean 56.6 vs 63.2 years) and were more apt to be women (47.3% vs 27.5%; P < 0.001 for both). There were no differences, however, in rates of heart failure, cardiorespiratory failure, or cardiogenic shock.

Probably these selected cases were also chosen because the operator felt that the possibility of opening the artery was there. Fernando Alfonso

In-hospital mortality didn’t differ significantly between the SCAD and non-SCAD patients with STEMI, no matter whether it was measured as crude (6.7% vs 4.8%), risk-standardized (5.3% for each), or propensity-score adjusted mortality (5.7% for each). Also similar were 30-day readmission rates, which hovered around 3-4%.

Predictors of in-hospital mortality included cardiogenic shock at admission (OR 25.2; 95% CI 22.6-28) and STEMI complications (OR 27; 95% CI 13.5-54).

A separate analysis consisting entirely of SCAD patients showed that, compared with those whose STEMI was managed conservatively, those who underwent primary PCI tended to have higher-risk characteristics—they were more likely to be older, to be men, and to have anterior STEMI, diabetes, cardiogenic shock, or heart failure.

“Our findings suggest that when indicated, primary PCI should not be withheld from patients with SCAD presenting with STEMI,” the authors conclude.

Velagapudi, Kirtane, and Saw agree. “In accordance with a recent expert consensus that recommends conservative management in stable SCAD patients, it is reassuring that in this more unstable presentation with ongoing ischemia, primary PCI may result in favorable short-term clinical outcomes,” they write in their editorial. “Accordingly, the risk of potential complications during PCI for SCAD should not withhold the possibility of offering coronary revascularization when clinically indicated.”

Why—or Why Not—Primary PCI?

One caveat to the current data set is that it doesn’t contain “exactly the reason why the procedures were performed,” Alfonso specified. For most SCAD cases, the bias would be against intervening, so there must have been something driving operators to pursue primary PCI in these patients, he added. “These were highly selected cases, and then probably these selected cases were also chosen because the operator felt that the possibility of opening the artery was there.”

What their findings suggest, said Alfonso, is that operators were adept at choosing when to revascularize.

Not every SCAD patient diagnosed with STEMI should proceed to primary PCI, he advised. “Some patients no longer have chest pain, so it's a good reason to stop. In some cases, the ST segment is not very elevated, just minor changes. And in some cases, even though the ST segment is elevated, the artery is open.”

Another reason to be conservative, Alfonso noted, is that disease in these patients can be diffuse and in a distal vessel. “So perhaps even though the flow is not good you say, ‘Enough is enough. I don't want to enter there [and] try to advance my catheters and my stents distally.’”

Yet to be seen is what the long-term outcomes will be for SCAD patients with STEMI. This information isn’t contained in administrative databases like the one that forms the basis of this study, said Alfonso. In Spain, there’s now a registry tracking all patients treated there for SCAD—this is of special interest because SCAD is such a diverse entity with many morphologies, he said. “Hopefully we will have the opportunity also to select the best intervention for each specific issue.”

Velagapudi agreed that additional research is needed. “Though the [current] study compared the outcomes, the registry itself didn’t have data about the procedure characteristics and the lesion characteristics, and whether intracoronary imaging was used or not,” she said. Future studies can help to identify which criteria should be used when deciding on whether to perform primary PCI in SCAD patients with STEMI, and examine the best approach to intracoronary imaging.

It also would be interesting to look into what medical therapy should be used post-PCI, she added. “Clearly, because these patients are [mostly] young women and they have a long lifespan to live, you want to prevent recurrences.”