Multivessel PCI May Be Safe in Select Shock Patients With Impella Support

In findings that run counter to those informing current guidelines, data from the National Cardiogenic Shock Initiative (NCSI) suggest that with early percutaneous mechanical circulatory support, select patients who have acute MI and cardiogenic shock (AMICS) may safely undergo multivessel intervention.

Multivessel and culprit-only PCI were associated with similar rates of hospital survival (69.8% vs 65.3%; P = 0.51) and acute kidney injury (29.9% vs 34.2%; P = 0.64) at hospitals adhering to the NCSI shock protocol, which calls for early support with an Impella device (Abiomed), revascularization, and invasive hemodynamic monitoring.

Median length of hospital stay also did not differ between groups (10 vs 8 days; P = 0.50), lead author Alejandro Lemor, MD (Henry Ford Hospital, Detroit, MI), and colleagues report in a study published online April 29, 2020, ahead of print in JACC: Cardiovascular Interventions. Both Henry Ford Hospital and Abiomed are funders of the NCSI.

“Our study provides evidence that performing multivessel PCI can be safely performed in selected cases in the setting of shock, as long as the patient is supported with a mechanical circulatory device and nonculprit lesions are not complex,” Lemor told TCTMD in an email.

But as previously reported by TCTMD, randomized controlled trial data on Impella are thus far restricted to the setting of high-risk PCI. Support for its use in AMICS comes primarily from observational studies and remains controversial. The first large randomized trial on the topic, DanGer, has not yet reported results. Abiomed also recently announced another AMICS-related trial: RECOVER IV.

In addition, the researchers’ conclusion is at odds with the CULPRIT-SHOCK trial, which showed that immediate multivessel PCI increased the composite of death or severe renal failure leading to renal replacement therapy at 30 days compared with culprit-only PCI (with the option to perform staged revascularization of nonculprit lesions).

US guidelines regarding revascularization in STEMI have not been updated since the CULPRIT-SHOCK results were released, but the 2013 STEMI guideline states that “in patients with cardiogenic shock due to pump failure, PCI of a severe stenosis in a large noninfarct artery might improve hemodynamic stability and should be considered during the primary procedure.” The latest European revascularization guidelines, updated with the CULPRIT-SHOCK results in mind, include a class III recommendation against routine revascularization of nonculprit lesions in the setting of cardiogenic shock.

On that background, Sunil Rao, MD (Duke University School of Medicine, Durham, NC), urged caution in interpreting Lemor et al’s results, pointing out that CULPRIT-SHOCK had more than three times the number of AMICS patients as are in the current analysis.

“This observational study that only looked at in-hospital outcomes and simply cannot adjust for unmeasured confounders really shouldn’t change the overall message that we should not routinely be doing multivessel PCI in the patients who come in with cardiogenic shock and MI,” Rao told TCTMD.

Dirk Westermann, MD, PhD (University Medical Center Hamburg-Eppendorf, Germany), agreed, saying: “I personally would still be careful [about going] for multivessel PCI in patients even when they are protected with an Impella.”

Controversy in Shock

Although prior randomized trials—most recently the COMPLETE trial—have supported complete versus culprit-only revascularization in the broader STEMI population, the issue is more controversial in the setting of AMICS.

It’s true that CULPRIT-SHOCK showed that 30-day outcomes were worse with immediate multivessel PCI. But it also doesn’t tell the whole story, Lemor suggested, in that roughly one-quarter of the patients in the trial’s multivessel PCI group had a chronic total occlusion, the volume of contrast used was greater than what was used in the NCSI, and less than 30% of patients received mechanical circulatory support.

Moreover, Lemor et al point out in their paper, two meta-analyses focused on AMICS—one of observational studies alone and one that also included CULPRIT-SHOCK—showed no differences between multivessel and culprit-only PCI in terms of short- or long-term outcomes. The latter analysis did, however, show that multivessel PCI was associated with more acute kidney injury.

To explore the issue in the context of universal Impella support, here the investigators examined data from the NCSI on 198 patients with AMICS and multivessel disease (mean age 64.2 years; 79.8% men) who were treated at 57 participating hospitals between July 2016 and December 2019. Three-quarters presented with STEMI, and 69.4% had cardiogenic shock on admission. Most patients (64%) underwent multivessel PCI during the index procedure, with the rest receiving culprit-only PCI.

Before the start of mechanical circulatory support, there were no differences in various hemodynamic measures between groups. At 12 hours, patients in the multivessel PCI group had worse cardiac performance and higher lactic acid levels, but those differences disappeared by 24 hours after PCI.

There also were no differences between groups in terms of hospital survival, the occurrence of acute kidney injury, or the length of the hospital stay.

“Performing nonculprit PCI should be carefully evaluated in this sick patient population,” Lemor said. “Operators should evaluate several factors, including age and comorbidities, as well as TIMI flow grade, presence of chronic total occlusions, the size and distribution of the vessel, underlying hemodynamics, and the patient’s hemodynamic reserve to guide the decision of performing multivessel PCI.”

A Call to Stick to the Randomized Data

Both Westermann and Rao acknowledged that there might be some patients with AMICS in whom multivessel PCI would be warranted, but said that deference should be given to the findings of the CULPRIT-SHOCK trial and that as a general rule culprit-only PCI is the preferred approach.

The idea that Impella support might facilitate use of multivessel PCI in this population “definitely has to be shown in a randomized clinical trial because there are so many confounding factors [in this analysis] that it’s extremely difficult comparing the two patient groups,” Westermann said.

“I think we have to be very, very careful in interpreting these observational data to replace what is really a well-done randomized trial,” Rao said. “I really think that this is thought-provoking [and] potentially hypothesis-generating, but it really should not be changing practice.”

Lemor conceded that “multivessel PCI in the setting of shock is not for everyone,” but also stressed that it “should not be forgotten, as some patients might benefit from this strategy.”

“We believe that in selected patients, following ‘best practice’ protocols, which include early PCI and mechanical circulatory support, will aid in the process of safely performing multivessel PCI without compromising kidney function and/or survival,” he said.

In an accompanying editorial, Michael Ragosta, MD (University of Virginia Health System, Charlottesville), calls for long-term data to inform the issue. “Until a properly designed trial is completed, the performance of nonculprit PCI supported by early use of mechanical circulatory support in shock patients with acute MI appears safe, but it remains unknown if outcomes are better than PCI of culprit lesions only,” he writes.