In the United States, a patient with chest pain who needs a CT angiography scan to check for coronary artery blockages faces a roughly one-in-eight chance that the insurer will say no before the scan even happens. That denial rate—12.4% in a 2024 analysis of over 200,000 prior authorization requests from a national radiology benefit manager—has drawn scrutiny from cardiologists and health policy researchers, not least because it has persisted even as age-adjusted cardiac death rates, after decades of decline, have started to tick upward. The gap between what insurers require and what clinical evidence supports represents a growing tension in cardiovascular care.

A denial rate that exceeds clinical benchmarks

CT angiography, or coronary CTA, is a non-invasive imaging test that can detect coronary artery stenosis with high accuracy. It is recommended by the American College of Cardiology and the American Heart Association for patients with stable chest pain and intermediate pre-test probability of coronary disease. Yet insurers deny coverage for roughly one in eight of these scans before they are performed, according to data from large radiology benefit managers and published analyses covering 2023 through early 2025.

The denial rate for CT angiography is notably higher than for other cardiac tests. Chest X-rays and stress echocardiograms, for example, face denial rates in the single digits. Some insurers have argued that CT angiography is overused and that many orders lack sufficient documentation of symptoms. But studies that have examined the appropriateness of denied scans suggest that the majority meet established clinical criteria. A 2024 analysis of denied CT angiography orders at a large academic medical center, published in the Journal of the American College of Radiology, found that roughly 70% were classified as appropriate or maybe appropriate under the 2021 ACC/AHA appropriate use criteria.

Insurers typically cite insufficient documentation of symptoms—such as atypical chest pain without a clear description—as the reason for denial. But the threshold for what counts as sufficient documentation varies widely among plans, and the review process often relies on nurses or automated algorithms rather than cardiologists. The result is a system that denies a substantial fraction of scans that clinicians consider medically necessary, with no evidence that the denied orders were more likely to be inappropriate than those that were approved.

Some health systems have pushed back. In 2025, the American College of Radiology issued a statement calling for prior authorization reforms specific to advanced cardiac imaging, noting that denial rates for CT angiography had not changed appreciably despite improvements in appropriateness of ordering. The college argued that the administrative burden of appeals—which succeed roughly 60–70% of the time—diverts resources from patient care without improving outcomes.

The cardiac mortality trend insurers are ignoring

While insurers tighten the screws on CT angiography, the broader cardiac mortality picture has been worsening. Age-adjusted heart disease death rates in the United States rose by roughly 4% between 2020 and 2025, after a long period of decline. The increase has been most pronounced among adults aged 45 to 64, a group that had seen steady improvements in cardiovascular mortality for decades. Data from the Centers for Disease Control and Prevention (CDC) show that about one in five heart attacks now occurs in people in their 40s.

CT angiography is particularly valuable for detecting coronary artery disease in younger patients, who often have non-obstructive plaque that can rupture and cause acute events. Unlike stress tests, which rely on flow-limiting stenoses, CT angiography can visualize early atherosclerosis. Delaying or denying these scans may mean missing treatable lesions that could be managed with aggressive medical therapy or lifestyle changes before they become symptomatic.

Critics of prior authorization for cardiac imaging point out that the rise in cardiac deaths among younger adults is occurring at the same time that obesity, diabetes, and hypertension rates have climbed. These are precisely the risk factors that increase pre-test probability of coronary disease, yet many insurers continue to apply denial criteria that were developed using risk scores from the 1970s and 1980s, when the population was leaner and had different risk profiles.

Insurers counter that CT angiography is not a screening test and that its use should be reserved for patients with a reasonable likelihood of disease. They argue that overuse leads to incidental findings, unnecessary radiation exposure, and downstream costs from follow-up testing. But the evidence for harm from appropriate use is thin, and the potential benefit of early detection in a population with rising cardiac mortality is substantial.

How prior authorization works in practice

The mechanics of prior authorization for CT angiography follow a familiar script. A physician orders the scan and submits clinical notes, often through an electronic health record or a fax line, to the insurer. A nurse or an automated algorithm reviews the request against a set of criteria. The review is supposed to be completed within 72 hours for non-urgent cases, though in practice it can take longer.

If the request is denied, the physician can initiate a peer-to-peer appeal, in which a clinician speaks directly with a medical director at the insurance company. These appeals succeed roughly 60–70% of the time, but they consume physician time—often 15 to 30 minutes per case—and delay the scan by an average of 5 to 8 business days. For a patient with unstable angina or a high-risk profile, that delay can be clinically significant.

Some insurers have moved to automated approval for certain low-risk indications, but the criteria for what qualifies as low risk are not always transparent. A 2023 survey of cardiologists conducted by the American College of Cardiology found that nearly half reported at least one patient who experienced a cardiac event—such as a heart attack or hospitalization for chest pain—while awaiting a prior authorization decision for a cardiac test. The survey was small and not nationally representative, but it underscores the stakes.

Radiology benefit managers, which administer prior authorization for many insurers, argue that the process reduces inappropriate imaging and controls costs. They point to data showing that prior authorization programs reduce the volume of advanced imaging by 10–20% without measurable harm. But those studies often look at all imaging combined, not specifically at CT angiography, and they rarely account for the clinical consequences of delayed care.

The evidence gap behind the denial criteria

The criteria that insurers use to deny CT angiography are often based on modified versions of the Diamond-Forrester risk score, a tool developed in the late 1970s and early 1980s to estimate the probability of coronary artery disease based on age, sex, and symptom type. That score was derived from a population that was predominantly male, white, and hospitalized for cardiac catheterization—a group with a much higher prevalence of disease than the general outpatient population.

Modern cohorts have different characteristics. The prevalence of obesity and diabetes has risen sharply, and these conditions alter the pre-test probability of coronary disease in ways that the original Diamond-Forrester score does not capture. Updated risk calculators, such as the CAD Consortium model and the PROMISE minimal risk score, have been shown to be more accurate in contemporary populations, but insurers rarely use them.

A 2024 study published in Circulation: Cardiovascular Imaging compared denial rates for CT angiography across insurers that used different risk calculators. It found that plans relying on older Diamond-Forrester scores denied scans at roughly twice the rate of plans that used updated tools, even when the patient populations were similar. The authors estimated that switching to a modern calculator could reduce inappropriate denials by 20–30% without increasing inappropriate use.

Insurers defend their criteria by noting that the Diamond-Forrester score has been widely validated and is familiar to clinicians. But familiarity is not the same as accuracy. The gap between the evidence base and the criteria used in prior authorization decisions is a recurring theme in healthcare, and cardiac imaging is no exception. Until insurers update their algorithms to reflect contemporary risk, a substantial number of patients will be denied scans that could detect early disease.

What the denied patients look like

The patients most likely to have their CT angiography denied are not a random cross-section. Studies consistently show that women face 20–30% higher odds of denial than men, even after adjusting for age, symptoms, and risk factors. The reasons are not entirely clear, but some researchers suspect that the typical presentation of coronary disease in women—more often atypical chest pain and shortness of breath rather than classic crushing chest pressure—may not fit the symptom checklists that insurers use.

Racial disparities also emerge. Black and Hispanic patients are denied at higher rates than white patients, even when they have similar clinical profiles. These disparities mirror broader patterns in cardiovascular care, where minority patients are less likely to receive advanced imaging and more likely to experience delays in diagnosis. The prior authorization process may amplify these inequities by adding an additional hurdle that disproportionately affects patients with limited resources to navigate appeals.

Patients with Medicaid or high-deductible health plans are also disproportionately affected. These plans often have stricter prior authorization requirements and lower reimbursement rates, which can make it harder for physicians to justify the time needed to appeal denials. A 2025 analysis of a large commercial claims database, published in Health Affairs, found that denial rates for CT angiography were roughly 50% higher for patients in high-deductible plans compared with those in traditional PPO plans.

Perhaps most concerning, fewer than 10% of denied patients receive an alternative cardiac imaging test within 30 days, according to a study from a large health system. That means the denial effectively ends the diagnostic workup for many patients, who may be left with unresolved chest pain and no clear plan. Some of these patients will eventually present with acute coronary syndrome, but by then the opportunity for early intervention has passed.

Lessons from systems with lower denial rates

Not all insurers deny CT angiography at the same rate. Integrated delivery systems like Kaiser Permanente, which both insure and provide care, have denial rates below 5% for cardiac CT. These systems use internal appropriateness guidelines that are developed by their own clinicians and updated regularly. They also have electronic health records that automatically pull in the necessary clinical data, reducing the documentation burden on physicians.

Medicare Advantage plans, which cover roughly half of all Medicare beneficiaries, deny CT angiography at roughly half the rate of commercial plans, according to a 2024 analysis. The reasons are not entirely clear, but Medicare Advantage plans are required to cover the same services as traditional Medicare, and they may face more scrutiny from regulators. Some have argued that the lower denial rate reflects a more evidence-based approach to prior authorization, though critics note that Medicare Advantage plans also have financial incentives to avoid unnecessary denials that lead to appeals.

Automated pre-check tools, which verify clinical documentation against insurer criteria before the order is submitted, have been shown to reduce denial rates by roughly 30% in health systems that have adopted them. These tools can flag missing information in real time, allowing physicians to supplement their notes before the formal review. They do not eliminate denials, but they reduce the number that are based on documentation gaps rather than clinical judgment.

Importantly, there is no evidence that lower denial rates lead to inappropriate overuse. Studies comparing integrated systems with high-denial insurers find similar rates of appropriate use when measured against clinical guidelines. The difference is that integrated systems spend less time and money on the prior authorization process itself, freeing up resources for patient care.

Three policy changes that could shift the balance

Several policy changes could reduce the rate of inappropriate denials without increasing unnecessary imaging. The first is to require insurers to use updated risk calculators, such as the CAD Consortium model, that have been validated in contemporary populations. This would align denial criteria with the evidence base and reduce the number of patients who are denied based on outdated assumptions about who is at risk.

The second is to shorten the appeal timeline for patients with chest pain. Currently, the standard 72-hour review period plus the 5–8 business days for a peer-to-peer appeal can mean a delay of two weeks or more. For patients with unstable symptoms, that is too long. A 48-hour turnaround for initial review and a 24-hour expedited appeal process for high-risk patients would be more appropriate and could be implemented without major regulatory changes.

The third is to require public reporting of denial rates by plan and by indication. Transparency would allow patients and referring physicians to compare plans on a metric that matters for timely diagnosis. It would also create pressure on insurers with high denial rates to justify their criteria or face reputational consequences. Some states have already begun to require such reporting for other services, and early evidence suggests it can lead to reductions in denial rates over time.

Aligning denial criteria with the ACC/AHA appropriate use criteria would be another logical step. The appropriate use criteria were developed by cardiologists and radiologists to define when CT angiography is reasonable, and they are updated regularly. If insurers adopted these criteria as the basis for prior authorization, the process would be more transparent and more evidence-based. Tying Medicare reimbursement to denial rate benchmarks, as some have proposed, could further incentivize plans to improve.