Evaluation of Integrated Cardiac Imaging in Ischemic Heart Disease: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Integrated Cardiac Imaging in Ischemic Heart Disease (NCT00979199), a na phase 4 study. The primary outcome is Diagnosis of IHD at Invasive Coronary Angiography and FFR Measurement.

2. Clinical Question

The registry identifies the condition as ischemic heart disease and frames the study around diagnostic assessment. That distinction matters: the question concerns how imaging findings relate to a reference diagnostic assessment, not whether an imaging strategy changes health outcomes compared with another strategy. It also means that interpretation depends on how the reference assessment was applied and how imaging results were evaluated. Those procedural and analytical details are not reported in the registry record.

The study is listed as phase four, completed, and single-group. Allocation is recorded as not applicable and masking as none. These entries indicate that the registry does not describe a randomized, blinded comparison of treatment arms. They do not, by themselves, establish how imaging decisions were made in practice or whether image interpretation was independent of the reference assessment.

The primary outcome is described as the number of participants diagnosed with ischemic heart disease at invasive coronary angiography, with fractional flow reserve used for intermediate lesions. Its timeframe is 3 months from enrollment. The record does not report how many participants received that diagnosis, nor does it give a comparison of imaging classifications against the reference diagnosis. The clinical question is therefore identifiable, while the results needed to quantify diagnostic performance are not reported in the registry record.

3. Trial Design

NCT00979199 is a completed phase four study titled Evaluation of Integrated Cardiac Imaging in Ischemic Heart Disease. The registry lists a single-group model, allocation as not applicable, and no masking. Enrollment is recorded as 697. The start is recorded as 2009-02 and primary completion as 2010-07. The sponsor is Fondazione C.N.R./Regione Toscana "G. Monasterio", Pisa, Italy.

The registered purpose was to assess diagnostic performance of non-invasive anatomical and functional imaging for detecting significant obstructive coronary artery disease. The reference assessment was invasive coronary angiography, with fractional flow reserve measurement for intermediate coronary lesions. In the intervention description, non-invasive cardiac imaging combines anatomical information from CT coronary angiography with functional information from stress imaging. The functional methods named are radionuclide imaging using SPECT or PET, stress MRI, and echocardiography. The registry says these methods were used in different combinations; it does not say which participants received which combination or provide the full protocol.

Because this is a single-group diagnostic study rather than a randomized comparison, the imaging assessment and invasive reference assessment have different roles. The imaging is the diagnostic approach under evaluation; angiography and, when relevant, fractional flow reserve form the stated reference. There is no separate control group against which to interpret the imaging strategy as a treatment. This design description should not be read as evidence that all aspects of diagnostic assessment were conducted without bias: blinding is recorded as none, while details about timing, interpretation procedures, and the handling of discordant assessments are not reported in the registry record.

The registry lists a primary outcome with a timeframe of 3 months from enrollment and a secondary outcome concerning cost-benefit and cost-effectiveness analysis. It records 2 outcome measures and 0 analyses. It does not report outcome results, diagnostic accuracy estimates, cost results, or analytic methods for either outcome. The posted sample-size material is a planning illustration based on the observed effect and assumptions of two-sided significance level 0.05, equal allocation between two arms, and a normal approximation. It is a hypothetical planning exercise, not a description of this single-group study's design or observed power. The registry record does not report the study's sample-size justification.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Diagnosis of IHD at Invasive Coronary Angiography and FFR Measurement, measured over 3 months from enrollment.

The primary endpoint is described as the number of participants diagnosed with ischemic heart disease at invasive coronary angiography, with fractional flow reserve measurement used in cases of intermediate coronary lesions. The stated timeframe is 3 months from enrollment. In plain terms, the endpoint concerns whether the invasive reference assessment identifies disease during the registered follow-up window. The outcome is recorded as a participant count, not as a continuous measurement.

This endpoint is relevant to the study's diagnostic aim because the non-invasive imaging methods are being assessed for their ability to detect significant obstructive coronary artery disease. A reference diagnosis is needed to judge whether imaging classifications correspond to disease established through the invasive assessment. Fractional flow reserve is specified for intermediate lesions, adding a functional assessment of those lesions to the angiographic evaluation.

As a general statistical point, a count of people meeting an outcome definition can describe how often that outcome was recorded, but a count alone does not quantify diagnostic performance. Assessing diagnostic performance ordinarily also requires information about how imaging results classify participants relative to the reference assessment. Measures such as sensitivity, specificity, or agreement depend on those paired classifications and on the analysis definitions. Those results and definitions are not reported in the registry record.

The registry does not report the primary endpoint count, the number assessed with the reference procedure, or the cross-classification of imaging and reference findings. It also does not give a detailed rule for diagnosing ischemic heart disease or for selecting lesions for fractional flow reserve assessment beyond the mention of intermediate lesions. Consequently, the endpoint's stated purpose can be explained, but its observed value and diagnostic implications cannot be quantified from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a diagnostic study, not a randomized clinical comparison of treatments. Its stated aim is to assess non-invasive anatomical and functional imaging for detecting significant obstructive coronary artery disease. Invasive coronary angiography is the reference assessment, and fractional flow reserve is used for intermediate coronary lesions. The distinction between the imaging approach under evaluation and the reference assessment is important: the design concerns agreement with a diagnostic standard, rather than a contrast between treatment assignments.

What does a diagnostic comparison require?

As a general statistical explanation, diagnostic performance is assessed by pairing each participant's index-test result with the reference result. The resulting classifications show whether the imaging and reference assessment agree, and where they disagree. Sensitivity describes the proportion of reference-positive cases that the index test identifies; specificity describes the proportion of reference-negative cases that it classifies as negative. These measures require the paired classification data and clearly defined thresholds. The registry record does not report those data or estimates, so no such measure can be interpreted for this study.

Predictive values answer a different question: among people with a positive or negative index-test result, what proportion has the corresponding reference status? In general, predictive values are affected by how common the condition is in the assessed population. They therefore should not be interpreted as fixed properties of an imaging method independent of population and clinical setting. No predictive values or prevalence estimate for the assessed participants are reported in the registry record.

Why does the reference procedure matter?

The endpoint description names invasive coronary angiography and fractional flow reserve measurement for intermediate coronary lesions. This indicates that the reference assessment was not described as angiography alone for every lesion. As a general matter, a reference standard should be applied consistently and its decision rules should be explicit, because differences in verification can affect apparent diagnostic performance. The registry does not provide detailed rules for identifying intermediate lesions, applying fractional flow reserve, or resolving a result that differs from imaging. These details cannot be inferred from the brief outcome description.

The record describes CT coronary angiography as supplying anatomical information and stress imaging as supplying functional information. It names SPECT or PET, as well as stress MRI or echocardiography, and says these were used in combination with CT coronary angiography. As a general matter, combining tests can yield a diagnostic strategy whose performance differs from that of any component alone. To interpret a combined strategy, the components, sequence, thresholds, and decision rule need to be known. The registry does not report those details or modality-specific results.

What can confidence intervals tell readers?

In general, a confidence interval expresses the uncertainty around an estimate under the statistical model used. A narrow interval indicates greater statistical precision than a wide interval, while neither width nor location alone resolves limitations in study conduct or representativeness. Diagnostic estimates are often reported with confidence intervals, but none are reported in the registry record. Without an estimate and its interval, readers cannot judge precision from this record. No interval should be reconstructed from the enrollment figure or adverse-event counts.

What does the planning illustration mean?

The posted sample-size material is a planning illustration computed from the observed effect, not the trial's own design. It assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. These are hypothetical planning assumptions. They do not describe the enrolled study, which is registered as single-group, and they do not establish observed power. The registry record does not report a sample-size justification for the actual study or a statistical plan linking the illustration to its diagnostic design.

In general, a planning calculation estimates the amount of information a future study might need under chosen assumptions. Its result depends on the target effect, variability or event frequency, allocation, statistical test, and desired error rates. If the assumed effect is optimistic or the model is poorly matched to the design, the planning result can be misleading. Planning calculations should not be treated as a post hoc measure of whether an observed study was adequately powered. The illustration's two-arm assumption is especially distinct from the registered single-group model.

How should the recorded design be read?

The registry lists allocation as not applicable and masking as none. These are design descriptors, not complete explanations of how participants were selected, how tests were interpreted, or whether any readers were kept unaware of other findings. In general, diagnostic studies can be affected by spectrum differences, selective verification, and interpretation bias. Spectrum differences arise when the assessed participants differ from the people in whom the test would later be used. Selective verification occurs when the reference procedure is not applied consistently. Interpretation bias can arise when readers know other test results. The record does not report enough detail to determine whether or how these issues arose.

The registry lists 2 outcome measures and 0 analyses. This establishes that analysis results are not recorded there, but does not explain whether analyses were conducted elsewhere, whether results were submitted, or what analysis plan was followed. A planned outcome and a reported outcome are not interchangeable. Because no primary result, diagnostic cross-classification, or uncertainty estimate is recorded, statistical interpretation must remain limited to the design and the outcome definition.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Non Invasive Cardiac Imaging")
n      <- c(475)
events <- c(140)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Non Invasive Cardiac Imaging  475  140  29.5  25.4  33.8  25.6  33.7  25.6  33.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures, including the primary diagnostic outcome and a secondary outcome concerning cost-benefit and cost-effectiveness analysis. It records 0 analyses. Results for these outcomes and an analysis plan are not reported in the registry record. The record does not state whether there were additional exploratory outcomes, subgroup comparisons, or repeated analyses.

As a general statistical matter, testing multiple outcomes or multiple versions of an outcome can increase the chance of finding an apparently notable result by chance. Methods for controlling or interpreting multiplicity depend on the study questions and analysis plan. The registry does not report whether any multiplicity adjustment was planned or used. It is therefore not possible to assess how the registered outcomes were prioritized in analysis or how any set of statistical tests was interpreted.

The registry record does not report missing-data counts, reasons for missingness, imputation methods, or sensitivity analyses. In general, missing data can affect estimates when participants without recorded outcomes differ systematically from those with complete information. For a diagnostic study, missing imaging results or absent reference assessments can also affect which participants contribute to paired performance estimates. The record does not report whether all enrolled participants received each assessment or how incomplete assessments were handled.

Analysis populations are not described. The registry does not specify whether the primary analysis included all enrolled participants, only those with both imaging and reference results, or another defined group. These distinctions matter because diagnostic estimates based on complete paired assessments may describe a selected subset if completion is related to clinical status or test findings.

The registry's lack of reported analyses should not be mistaken for evidence that no analyses were conducted. It means that the analysis methods and results are not reported in the registry record, so multiplicity, missing-data handling, and the population underlying any estimate cannot be evaluated from that record.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists a serious adverse-event category for the Non Invasive Cardiac Imaging group, with 475 at risk and 0 affected. It also lists 475 at risk and 5 affected in the other adverse-event category. These are the posted counts; the registry does not provide event descriptions, timing, severity definitions, or a narrative explaining the events. The deaths field is null, which means a death count is not reported in the registry record.

The two categories should be read as separately recorded entries, not combined into a new total. The record does not explain whether the groups of people represented by the at-risk counts overlap, and it does not define the other-event category in the information available. No rate should be inferred from these entries, and the counts do not establish causation or comparative safety.

As a general point, adverse-event counts depend on how events are defined, collected, and attributed, and on the duration of observation. Here the primary outcome timeframe is 3 months from enrollment, but the safety entries do not give their own observation window. The registry also does not report a comparator arm, detailed safety methods, or a complete event listing. The posted figures therefore describe the registry's recorded counts only; they do not support a broader conclusion about the safety of an imaging modality.

13. What the Result Does, and Does Not, Mean

The registry record establishes that this completed study was designed to assess non-invasive cardiac imaging for detection of significant obstructive coronary artery disease. It describes CT coronary angiography for anatomical information and stress imaging for functional information, with invasive coronary angiography and fractional flow reserve measurement for intermediate lesions as the reference assessment. It also records enrollment of 697 and a primary outcome timeframe of 3 months from enrollment.

Those design details identify the study's intended diagnostic question, but they do not show the answer. The record does not report the number of participants diagnosed with ischemic heart disease, the paired imaging and reference results, or measures of diagnostic performance. It also does not give confidence intervals or other measures of statistical uncertainty. As a result, the registry record cannot establish how often imaging findings agreed with the reference assessment or how precisely any performance estimate was measured.

The record does not establish that one imaging method performed better than another. It describes several possible functional modalities, but does not give participant-level modality assignments or results by modality. Nor does it report a comparison between imaging and a randomized control group; the study is registered as single-group, with allocation not applicable and no masking.

These limitations do not show that the imaging methods were inaccurate or that the study produced no findings. They mean that the registry record does not report the evidence needed to evaluate those questions. The posted planning illustration is not a result and is not observed power. The recorded adverse-event counts are limited registry entries and cannot establish whether events were caused by imaging or support a comparative safety conclusion.

In general, diagnostic evidence is strongest to interpret when the index-test and reference procedures are clearly specified, applied in a way that limits bias, and reported with paired results and uncertainty estimates. The registry provides a high-level description of the question and reference procedure, but the implementation details and results needed for that assessment are not reported. The appropriate reading is therefore descriptive: the study's registered purpose and design are clear, while its diagnostic findings cannot be quantified from the registry record.

14. Why This Trial Matters Statistically

This study raises a statistically important distinction between evaluating a diagnostic test and evaluating a treatment. The registered aim is to compare non-invasive anatomical and functional imaging with invasive coronary angiography and fractional flow reserve assessment. That is a question about classification and agreement with a reference assessment. It is not, on the information in the registry, a randomized comparison of treatment effects.

For diagnostic research, a description of the test and its intended role is not enough to estimate performance. Readers need paired results that indicate how index-test findings correspond to the reference assessment, alongside clear decision thresholds and uncertainty measures. The registry describes the reference procedure and the broad imaging components, but does not report the paired findings or performance estimates. This makes the boundary between a registered study objective and an interpretable statistical result especially visible.

The record also illustrates why design assumptions must fit the analysis question. The study is registered as single-group, while the posted planning illustration assumes equal allocation between two arms and a normal approximation. That illustration may serve as a hypothetical planning exercise under its stated assumptions, but it does not describe this study's design or establish observed power. Treating such planning output as evidence about the trial would confuse a future-study calculation with an observed result.

Finally, the registry shows how outcome definitions and analysis reporting contribute different pieces of evidence. The primary endpoint and timeframe are specified, but its count and analysis are not reported. A clearly named outcome supports understanding what was intended to be measured; without results and methods, it does not support a conclusion about what was found. This separation is relevant to clinical researchers assessing whether registry entries provide enough information to interpret diagnostic evidence.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation for interpreting this specific study is that the registry record does not report primary outcome results or diagnostic-performance estimates. The endpoint is defined as the number of participants diagnosed with ischemic heart disease at invasive coronary angiography, with fractional flow reserve measurement for intermediate lesions, but the count is absent. The record also lacks paired imaging and reference classifications, so accuracy measures cannot be assessed.

The imaging strategy is described at a broad level rather than as a fully specified protocol. CT coronary angiography is described as the anatomical component, with functional information from SPECT or PET and/or stress MRI or echocardiography. The registry does not report modality-specific assignments, testing sequence, thresholds, image-reading rules, or subgroup results. This limits interpretation of the intervention as a single reproducible diagnostic strategy and prevents comparisons among the named modalities.

Although the reference assessment is identified, the record does not provide detailed procedures for defining intermediate lesions, applying fractional flow reserve, or resolving discordant results. It also records no masking, without describing whether interpreters had access to other test findings. These gaps prevent assessment of possible verification or interpretation bias from the registry record.

The record does not report participant eligibility criteria, baseline characteristics, missing-data handling, analysis populations, or the statistical analysis plan. Enrollment of 697 does not establish how many participants completed each test or contributed to a paired analysis. The registry lists a secondary cost-benefit and cost-effectiveness outcome, but its results and methods are not reported. It also records 0 analyses, so no reported statistical estimates can be evaluated for precision or robustness.

Finally, the sample-size material is a planning illustration with assumptions that differ from the registered single-group design. The registry does not report a sample-size justification for the actual study. These limitations concern what the registry records and do not establish that the study itself lacked additional methods or findings outside the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of Integrated Cardiac Imaging in Ischemic Heart Disease — NCT00979199.
• Registry record last updated 2014-07-21; status last verified 2014-06.
• Results first posted 2014-07-21.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT00979199 is a completed phase four, single-group diagnostic-imaging study sponsored by Fondazione C.N.R./Regione Toscana "G. Monasterio", Pisa, Italy. The registry records enrollment of 697, a start of 2009-02, and primary completion of 2010-07. Allocation is listed as not applicable and masking as none.

The study aimed to assess non-invasive anatomical and functional imaging for detection of significant obstructive coronary artery disease against invasive coronary angiography, with fractional flow reserve for intermediate coronary lesions. The primary endpoint is the number diagnosed with ischemic heart disease within 3 months from enrollment. The registry also lists a secondary cost-benefit and cost-effectiveness outcome.

The registry records 2 outcome measures and 0 analyses. It does not report the primary outcome count, diagnostic-performance results, statistical analysis methods, or cost-effectiveness findings. The serious adverse-event entry lists 0 affected among 475 at risk; the other adverse-event entry lists 5 affected among 475 at risk. A death count is not reported in the registry record.