Previous studies indicate that early revascularization appears to reduce mortality among patients with acute MI that is complicated by cardiogenic shock. Approximately 80% of MI patients with cardiogenic shock present with multivessel coronary artery disease. For these patients, current European guidelines for the management of acute STEMI recommend immediate PCI of both culprit and nonculprit lesions. In the United States, appropriate-use criteria consider immediate revascularization of both culprit and nonculprit arteries during the same procedure to be highly appropriate. However, these appropriate-use criteria were based on an expert consensus, and recommendations were not based on evidence. Since cardiogenic shock has a high mortality rate, particularly in those with multivessel coronary artery disease, Holger Thiele, MD, and colleagues felt the issues needed to be addressed in a randomized trial.
Addressing the Issue
For a study published in the New England Journal of Medicine, Holger Thiele, MD, and colleagues randomly assigned patients with acute MI that was complicated by cardiogenic shock to either culprit-lesion-only PCI or immediate multivessel PCI. Dubbed the Culprit Lesion Only PCI versus Multivessel PCI in Cardiogenic Shock (CULPRIT-SHOCK) trial, study had a primary endpoint of risk for a composite of all-cause mortality or severe renal failure leading renal replacement therapy. Prespecified secondary end points at 1 year included death from any cause, recurrent MI, repeat revascularization, rehospitalization for congestive heart failure, the composite of death or recurrent infarction, and the composite of death, recurrent infarction, and rehospitalization for heart failure. Patients were eligible for the trial if they met the following criteria: planned early revascularization by means of PCI, multivessel coronary artery disease (defined as at least two major vessels [≥2 mm diameter] with >70% stenosis of the diameter), and an identifiable culprit lesion.
In all patients, the culprit lesion was treated first with the use of standard PCI techniques and with the recommended use of drug-eluting stents. In patients in the culprit-lesion-only PCI group, all other lesions were to be left untreated at the time of the initial procedure.
At 30 days, the primary end point had occurred in 45.9% of the patients in the culprit-lesion-only PCI group and in 55.4% in the multivessel PCI group. At 1 year, death had occurred in 50.0% of the culprit-lesion-only PCI group and in 56.9% of the multivessel PCI group (Table). The rates of recurrent infarction were 1.7% with culprit-lesion-only PCI and 2.1% with multivessel PCI, and the rates of a composite of death or recurrent infarction were 50.9% and 58.4%, respectively. Repeat revascularization occurred more frequently with culprit-lesion-only PCI than with multivessel PCI (32.3% vs 9.4%), as did rehospitalization for heart failure (5.2% vs 1.2%). Since culprit-lesion-only PCI has shown a benefit over multivessel PCI with respect to short-term survival, the risk of heart failure within the first year may be higher with culprit-lesion-only PCI than with multivessel PCI.
A post hoc landmark analysis revealed a difference between the two groups in mortality within the first 30 days (relative risk [RR], 0.84), but mortality was similar in the two groups thereafter (RR, 1.08). Between 30 days and 1 year, 6.7% of patients died in the culprit-lesion-only PCI group and 5.3% died in the multivessel PCI group.
“Culprit-lesion-only PCI reduced the primary endpoint of the trial, by roughly 10%,” says Dr. Thiele. “This was mainly driven by an absolute reduction of 8% in mortality. Immediate multivessel PCI should not be performed in clinical practice any longer. What’s more, our 1-year follow-up results could confirm the 30-day results. For the interventional cardiologist, this means that keeping it simple is better. Physicians should perform PCI of the infarct-related artery and treat the other lesions later after stabilization if they induce angina pectoris or ischemia.”
Dr. Thiele also indicates that European guidelines have already been changed based on the CULPRIT-SHOCK results, with more time needed to determine how and when the results will be integrated into clinical practice.
Dr. Thiele stresses that, based on his studies, he is unsure if immediate bypass surgery would be better than culprit-lesion-only PCI. Furthermore, the most important issue currently is whether or not mechanical circulatory support devices may be able to help reduce the still high mortality rates seen in the study population, he says, adding that trials on mechanical circulatory support devices are currently ongoing.