What we know—and don’t know—about assessing nonculprit lesions after STEMI

The complete revascularization (CR) of nonculprit lesions (NCLs) after ST-segment elevation myocardial infarction (STEMI) leads to better outcomes, according to a series of recent clinical trials. But how should NCLs be evaluated? And when is the ideal time for CR to occur?

A team of researchers addressed those very questions, sharing its analysis in JACC: Cardiovascular Interventions. Ultimately, the authors observed, more research is still needed into this incredibly important area.

The authors explored five recent clinical trials that compared CR with percutaneous coronary intervention (PCI) to culprit-only PCI: PRAMI, CvLPRIT, DANAMI-3, COMPARE-ACUTE and COMPLETE. Overall, the team noted, CR “was associated with reduced risk for major adverse cardiovascular events, driven mainly by reductions in myocardial infarction and repeat revascularization.” Limitations were observed—including the fact that patient selection for the trials was “incompletely described”—but the benefits of CR for STEMI patients were clear.

When it came to some more specific details, however, it was more difficult to reach definite conclusions.

For instance, the authors hoped to determine the most effective way to assess NCLs.

“Emergency coronary angiography with immediate revascularization of the culprit artery is strongly recommended in patients with STEMI,” wrote Troels Thim, MD, PhD, Aarhus University Hospital in Denmark, and colleagues. “At this time, NCLs of potential significance may be identified, and their angiographic severity can be visually estimated. However, angiographic assessment is not always a good predictor of functional significance, even in patients in stable condition.”

Angiographic assessments, the authors added, are far from perfect—and other potential options were discussed as well. Coronary flow reserve, for instance, is not recommended as a way to evaluate NCLs, and fractional flow reserve may lead to underestimates.

Instead of declaring that one method was the clear-cut path for any specialists looking to evaluate NCLs, the team emphasized that more research is needed. They did note, however, that “acute and subacute physiological changes may affect the evaluation of NCLs during the index procedure and the index hospitalization.”

Another key question Thim et al. wanted to explore was when CR should occur. Should the procedure take place right away be scheduled for a later date?   

“Pragmatically, lacking firm randomized data, the operator must weigh possible risks and benefits in each individual case,” the authors wrote. “In the periprocedural acute setting, embarking on NCL revascularization in hemodynamically unstable patients should generally be discouraged unless the clinician believes that treating the NCL will stabilize the patient. However, guidelines suggest that revascularization of NCLs can be considered in selected, hemodynamically stable patients with STEMI and multivessel disease on the basis of the evidence from PRAMI, CvLPRIT, and COMPARE-ACUTE.”

For now, the team has recommended weighing all options on a case-by-case basis—but did note that CR before discharge appears to be a perfectly effective option.

“When staged revascularization is considered, individual assessment of optimal timing from case to case is advised,” Thim and colleagues wrote. “During the index admission, unforeseen procedural complications may be less well tolerated than at a later time point. In contrast, CR before discharge may allay patient concerns and reduces costs associated with an additional staged hospitalization. Furthermore, the results from the five randomized clinical trials all suggest this to be an acceptable strategy.”