ISCHEMIA population underrepresented among those who undergo PCI for stable CAD
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In a cohort of real-world patients with stable ischemic heart disease who underwent PCI, only 14% could be classified similarly to patients from the ISCHEMIA trial, researchers reported.
As Healio previously reported, in the main results of the ISCHEMIA trial of patients with stable ischemic heart disease, there was no difference in clinical outcomes between patients assigned an invasive strategy, which included PCI in 79% of cases, or those assigned a conservative strategy at 4 years, although patients with regular angina symptoms assigned the invasive strategy reported improvements in angina-related quality of life measures.
For an analysis presented at the virtual Society for Cardiovascular Angiography and Interventions Scientific Sessions, the researchers included 388,212 patients with stable ischemic heart disease who underwent PCI from October 2017 to June 2019 and were included in the National Cardiovascular Data Registry CathPCI Registry.
“What was not well recognized was the population who were excluded from ISCHEMIA,” which included not only patients with urgent conditions such as ACS and cardiogenic shock, but also patients with stable CAD with certain comorbidities, high bleeding risk or unfavorable coronary anatomy, Saurav Chatterjee, MD, cardiologist at Northwell Health, said during a presentation. “That made us hypothesize that, potentially, this would lead to exclusion of a significant proportion of patients who are routinely considered for revascularization in practice. Additionally, patients were enrolled over a decade [for ISCHEMIA], which may not be representative of the most current form of practice.”
The researchers stratified the cohort with stable ischemic heart disease into ISCHEMIA-like, defined as those who had intermediate- or high-risk findings on a stress test or a positive assessment from an invasive test such as fractional flow reserve or instantaneous wave-free ratio; high-risk, defined as those who had ejection fraction less than 35%, left main CAD, end-stage renal disease, a recent congestive HF exacerbation or a heart transplant; low-risk, defined as those who had negative or low-risk findings on a stress test or a negative assessment from an invasive test; and not classifiable, defined as those who did not conform to any of the other groups.
Among all 927,011 patients from the registry who had PCI, 14% were ISCHEMIA-like, 8% had high-risk stable CAD, 7% had low-risk stable CAD and 13% had stable CAD but were unclassifiable, Chatterjee said, noting the remaining 58% had ACS, cardiac arrest and/or cardiogenic shock.
Among those with stable ischemic heart disease, 18.5% had high-risk criteria, 35.2% had left main stenosis, 43.7% had left ventricular ejection fraction less than 35%, 16.8% had end-stage renal disease and 31.9% were unclassifiable, often because there was no stress testing or the extent of ischemia was not reported on the stress test, he said.
Also, he said, at the median hospital participating in the registry, only 32.1% of patients who had stable ischemic heart disease and underwent PCI fit the ISCHEMIA-like category.
Although clinical outcome results from an observational study must be interpreted with caution, among those with stable ischemic heart disease, the ISCHEMIA-like group had lower rates of in-hospital death, bleeding and new requirement for dialysis compared with the other groups, Chatterjee said.
“A large proportion of contemporary patients undergoing PCI for stable ischemic heart disease in the U.S. would not have met criteria for ISCHEMIA,” he said. “There was significant variability in patient selection for stable ischemic heart disease PCIs throughout different centers in the U.S. While ISCHEMIA guides a certain component of our clinical decision-making, it does not represent all patients who undergo PCI. Future research needs to derive the appropriate cohort who will receive the most benefit with PCI, particularly among patients with stable ischemic heart disease.”
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Chatterjee S, et al. Featured Clinical Research: Stable ischemic heart disease and TAVR. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; April 28-May 1, 2021 (virtual meeting).
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