ISCHEMIA: Intermediate left main disease confers poor prognosis; invasive strategy improves angina symptoms
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In a new analysis from the ISCHEMIA trial of patients with stable ischemic heart disease, those with intermediate left main disease had worse prognosis than those with little or no left main stenosis, but an invasive strategy improved their angina-related quality of life.
For the prespecified analysis, researchers compared 962 patients from ISCHEMIA with intermediate left main stenosis, defined as 25% to 49% on coronary CT angiography, with 2,737 patients with left main stenosis of less than 25%, Cardiology Today Editorial Board Member Sripal Bangalore, MD, MHA, professor of medicine at the NYU Grossman School of Medicine, said during a press conference at the virtual Society for Cardiovascular Angiography and Interventions Scientific Sessions. Patients with left main stenosis of 50% or more were excluded from the trial.
“Patients who had intermediate left main disease on coronary CT tended to have a higher amount of ischemia,” Bangalore said during the press conference. “In patients who had intermediate left main disease, there was more of a proportion of patients with triple-vessel disease, and more of a proportion with left anterior descending artery disease, particularly proximal LAD.”
When patients assigned to an invasive strategy underwent coronary angiography, 7% of those identified as having intermediate left main disease on coronary CT actually had left main stenosis of at least 50%, whereas 1.4% of those identified as having less than 25% left main stenosis on coronary CT actually had left main disease, he said.
Among patients assigned the invasive strategy, CABG was performed in 32.1% of those in the intermediate left main disease group compared with 18.2% of those in the less than 25% left main stenosis group, whereas PCI was less common in the intermediate left main disease group (49.7% vs. 61.5%), Bangalore said.
In the entire cohort, he said, compared with the less than 25% left main stenosis group, the intermediate left main disease group had greater risk for the following 4-year outcomes:
- the ISCHEMIA primary endpoint of time to CV death, MI, hospitalization for unstable angina, HF or resuscitated cardiac arrest (HR = 1.31; 95% CI, 1.06-1.61);
- CV death, MI or stroke (HR = 1.3; 95% CI, 1.05-1.6);
- CV death (HR = 1.63; 95% CI, 1.11-2.39);
- procedural primary MI (HR = 1.64; 95% CI, 1-2.67);
- HF (HR = 2.06; 95% CI, 1.1-3.84); and
- stroke (HR = 1.82; 95% CI, 1.04-3.2).
In the main trial, patients assigned the invasive strategy had reduced risk for nonprocedural MI compared with those assigned the conservative strategy, but Bangalore said the treatment effect was greater in those who had intermediate left main disease compared with those who did not (P for interaction = .049).
The invasive strategy was associated with improved Seattle Angina Questionnaire (SAQ) angina frequency score in those with frequent or occasional angina regardless of whether patients had intermediate left main disease or not, Bangalore said.
“There was no evidence of a meaningful treatment effect across left main severity,” he said. “There was no difference in invasive vs. conservative strategy for primary and major secondary outcomes, but an invasive strategy was associated with an increase in procedural MI and a significant decrease in nonprocedural MI. There was significant and durable benefit of the invasive strategy on angina-related quality of life.”
Because patients with intermediate left main disease are at elevated risk for CV events, “we are going to have to be very aggressive in trying to reduce their risk, with medical therapy for secondary prevention, etc,” Bangalore said during the press conference. “My interpretation of the trial is that the patient has two options. They can choose an invasive strategy because it has a significant benefit of making you feel better and potentially reducing the risk of spontaneous MI after a time if you are willing to take a small upfront risk for procedural MI, or they can try medical therapy first. Both are reasonable options for these patients.” – by Erik Swain
Reference:
Bangalore S, et al. Featured Clinical Research. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; May 14-16, 2020 (virtual meeting).
Disclosure: Bangalore reports he received a research grant from Abbott and consultant fees/honoraria from Abbott, Amgen, Biotronik, Meril, Pfizer, Reata and SMT.
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Bangalore S, et al. Featured Clinical Research. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; May 14-16, 2020 (virtual meeting).
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