Even After Multivessel or LM PCI, Routine Stress Testing Adds Nothing

Even in patients with multivessel or left main coronary artery disease, routine functional testing after PCI adds no benefit, according to a new subanalysis of the POST-PCI trial supporting the study’s main results.

The original findings showed, in a general cohort of PCI patients with high-risk anatomical features or clinical characteristics, that stress testing had no impact on 2-year outcomes compared with standard care. Researchers, at the time, suggested routine functional tests in that overall population should be discouraged.

“In routine PCI practice, many physicians are still conducting regular surveillance stress testing after multivessel or left main PCI,” senior author Duk-Woo Park, MD (University of Ulsan College of Medicine, Seoul, Republic of Korea), told TCTMD in an email. “The main reasons for this would be that treating physicians are still concerned that the residual risks (owing to restenosis, lesion progression, or other ischemic risks) would be considerable after complex PCI, especially [after] multivessel or left main PCI.”

As such, for this analysis investigators zeroed in on patients with either left main or multivessel disease, but again they found functional tests added nothing to patient management or outcomes. “We must refrain from prescribing surveillance stress testing to our patients after PCI, in the absence of other clinical signs or symptoms suggestive of stent failure, among patients who undergo multivessel or left main PCI,” Park said.

The latest results were published in the March 5, 2024, issue of the Journal of the American College of Cardiology.

“These study findings further corroborate evidence from the ISCHEMIA trial,” argues Debabrata Mukherjee, MD (Texas Tech University Health Sciences Center, El Paso), in an accompanying editorial. “Based on these and other data, the totality of evidence at this time underscore the lack of benefit of routine stress testing in asymptomatic patients.”

The POST-PCI researchers, too, compare their study against ISCHEMIA.

“Although the ISCHEMIA trial primarily focused on the initial treatment strategy and the POST-PCI trial focused on the follow-up surveillance strategy, both highlight the lack of benefit of routine functional stress testing in asymptomatic patients after PCI,” they write.

Their new findings, the investigators say, “reemphasize that stringent follow-up surveillance with routine functional testing has no clinical benefit compared with standard care alone after multivessel or left main PCI, which is frequently performed in routine clinical practice.”

The most-recent US guidelines, from 2023, give routine stress testing after PCI a class III indication, while European guidance offers a class IIb recommendation. Mukherjee argues in his editorial that this analysis further supports these guidelines, especially since registry data indicate that up to half of PCI patients undergo stress testing within 2 years.

With the American Heart Association designating post-PCI stress testing as “low-value care,” Mukherjee further suggests that a “multipronged approach to mitigate this overuse including physician education, payment reform for inappropriate testing, and possible penalty for inappropriate use of these tests” will be necessary.

Triggering the Oculostenotic Reflex?

For the subanalysis, Joong Min Lee, MD (University of Ulsan College of Medicine), Park, and colleagues included 1,192 patients with multivessel (n = 833) or left main disease (n = 359) from the original trial. Around three-quarters presented with stable angina or silent ischemia, while approximately 10% had stable angina, 10% had NSTEMI, and the rest STEMI.

Rates of the primary outcome—a composite of all-cause death, MI, or hospitalization for unstable angina—were similar between the 589 patients in the functional-testing group and 603 patients in the standard-care group at 2 years (6.2% vs 5.7%; HR 1.09; 95% CI 0.68-1.74). Notably, more than half (52.7%) of those randomized to functional testing underwent multiple stress tests.

Nearly identical results were seen when the analyses were limited to patients with only multivessel disease (6.2% vs 5.7%; HR 1.09; 95% CI 0.62-1.89) or only left main disease (6.2% vs 5.7%; HR 1.09; 95% CI 0.46-2.56; P for interaction = 0.90).

Additionally, the researchers observed a trend toward more invasive coronary angiography (13.5% vs 9.6%; P = 0.06) and significantly more repeat revascularization (9.6% vs 6.0%; P = 0.03) after 1 year with routine surveillance functional testing.

The authors refer to the “oculostenotic reflex” that the additional information gleaned by stress testing might trigger in certain physicians. “Moreover, increased unnecessary procedures may lead to an elevated radiation exposure, potentially harming both patients and medical staff members, and invasive procedures can bring unexpected additional complications, potentially causing further detriment to patients,” they write.

“Although the present study had insufficient statistical power to allow for a firm conclusion, our findings do not support an active follow-up surveillance strategy with routine functional testing after multivessel or left main PCI,” Lee et al conclude.

Similar Findings in Diabetes

In another subanalysis of the POST-PCI trial, this one published last week in the European Heart Journal, the same team of researchers found that diabetes status also had no effect on the utility of routine functional testing after PCI.

The 1,706 patients with diabetes from the main trial had a greater risk of experiencing a primary endpoint event than nondiabetic patients, but 2-year rates of the primary composite outcome were similar whether they underwent routine functional testing or received standard care.

“The key results of the present study indicated that, compared with standard care alone, routine functional testing did not result in lower rates of ischemic cardiovascular events or mortality in high-risk patients with diabetes who underwent complex PCI,” the authors write. “Therefore, in the absence of other clinical signs or symptoms suggestive of stent failure, diabetic patients should not undergo routine surveillance stress testing after PCI.”