In ISCHEMIA population, invasive group benefits from complete revascularization
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Among patients with stable CAD assigned to an invasive strategy in the ISCHEMIA trial, those who achieved complete revascularization had better clinical and quality of life outcomes, researchers reported.
As Healio previously reported, in the overall results of ISCHEMIA, which had 5,179 patients, there was no difference in clinical outcomes at 4 years between those assigned an invasive strategy and those assigned a conservative strategy, but angina-related QOL was better in the invasive group among those with frequent angina. In two presentations at the American College of Cardiology Scientific Session, researchers discussed the impact of achieving anatomic and/or functional complete revascularization on clinical outcomes and QOL metrics.
Clinical outcomes
Although the impact of complete revascularization in patients with stable CAD has been studied before, it had never been assessed against patients managed conservatively, and it had never been ascertained by a comprehensive core lab assessment, Gregg W. Stone, MD, director of academic affairs for the Mount Sinai Heart Health System and professor of medicine and population health sciences and policy at the Zena and Michael A. Wiener Cardiovascular Institute at the Icahn School of Medicine at Mount Sinai, said during a presentation.
“We sought to assess the frequency and outcomes of anatomic complete revascularization and functional complete revascularization compared with incomplete revascularization in patients treated with an invasive management strategy, and to assess the impact that achieving complete revascularization in all patients randomized to an invasive strategy might have had compared with conservative management,” Stone said during a presentation.
Anatomic complete revascularization was defined as revascularization of all lesions with reference vessel diameter 2 mm or greater and percent diameter stenosis at least 50%. Functional complete revascularization was defined as revascularization of all lesions with reference vessel diameter 2 mm or greater and localizing or nonlocalizing ischemia.
In the invasive group, 1,802 patients could be assessed for anatomic complete revascularization and 1,743 could be assessed for functional complete revascularization. The rate of anatomic complete revascularization was 43.3%, and the rate of functional complete revascularization was 58.3%, Stone said.
In patients assigned to the invasive strategy, at 4 years, the primary endpoint of CV death, MI or hospitalization for cardiac arrest, HF or unstable angina occurred in 9.3% of those who had anatomic complete revascularization compared with 13.8% of those who did not (difference, –4.5 percentage points; 95% CI, –7.9 to –1.2) and in 10.3% of those who had functional complete revascularization compared with 14% of those who did not (difference, –3.7 percentage points; 95% CI, –7.2 to –0.2), Stone said.
In both comparisons, the difference was significant when unadjusted but not when adjusted for covariates (adjusted HR for complete vs. incomplete anatomic revascularization = 0.79; 95% CI, 0.55-1.15; P = .22; aHR for complete vs. incomplete functional revascularization = 0.96; 95% CI, 0.68-1.34; P = .8), according to the researchers.
The researchers also conducted an inverse probability of treatment weighting analysis comparing 2,296 patients from the invasive group for whom completeness of revascularization data were available with 2,498 patients from the conservative group who did not have prior CABG. The idea was to determine the hypothetical ideal treatment effect if all patients from the invasive group received complete revascularization, Stone said.
In that model, the primary outcome was lower in the conservative group than the invasive anatomic complete revascularization group at 6 months, but the reverse was true at 4 years, with the curves crossing earlier than they did in the overall ISCHEMIA trial, Stone said. A similar pattern occurred when comparing the conservative group with the functional complete revascularization group, but the between-group difference at 4 years favored the complete revascularization group to a lesser degree, he said.
Compared with the overall results of ISCHEMIA, the 4-year difference in the primary outcome was about 1% larger in favor of the invasive strategy in the anatomic complete revascularization. “Most of the increase in difference was due to fewer events for cardiovascular death and myocardial infarction,” Stone said. “In functional complete revascularization, there was a similar pattern, but there was really no difference in the adjusted event rates in patients who achieved functional complete revascularization vs. the overall ISCHEMIA trial, so there was much less of an effect.
“The outcomes of an invasive strategy may be improved if anatomic complete revascularization is achieved. The likelihood of safely achieving anatomic complete revascularization should therefore be considered when selecting between an invasive and a conservative approach in patients with chronic coronary disease,” he said.
QOL outcomes
For the QOL analysis, there were no differences in completeness of revascularization by baseline symptoms or baseline QOL metrics, Kreton Mavromatis, MD, associate professor of medicine at Emory University and director of the cardiac catheterization laboratory at the Atlanta VA Medical Center, said during a presentation.
Patients with more complex anatomy were less likely to achieve anatomic or functional complete revascularization, he said.
At 1 year, the Seattle Angina Questionnaire (SAQ)-7 summary score, the SAQ-7 angina frequency score, the SAQ-7 QOL score, the SAQ-7 physical limitation score and the Rose Dyspnea Scale score all favored those who achieved complete revascularization compared with those who did not, except for the SAQ-7 QOL score in patients with anatomic complete revascularization, he said.
The improvement in QOL metrics was most pronounced in those who achieved complete revascularization and had daily or weekly angina, Mavromatis said.
Propensity-weighted SAQ scores were higher in those who achieved complete revascularization than in those assigned to the conservative group, to a greater degree than seen in the overall ISCHEMIA trial, he said, noting there was no impact on Rose Dyspnea Scale score.
“Complete revascularization seems to be associated with improvement in angina-related quality of life than incomplete revascularization, particularly in patients with baseline weekly or daily angina,” Mavromatis said during the presentation. “Invasive management including complete revascularization improves ischemia-related quality of life more than conservative management, with greater benefits in the patients with more angina. These results suggest that for patients with chronic coronary disease and angina who are being managed invasively, the safe achievement of complete revascularization will optimize quality of life.”
Reference:
- Mavromatis K, et al. Featured Clinical Research III. Presented at: American College of Cardiology Scientific Session; May 15-17, 2021 (virtual meeting).
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Stone GW, et al. Featured Clinical Research III. Presented at: American College of Cardiology Scientific Session; May 15-17, 2021 (virtual meeting).
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