PRESSUREwire Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PRESSUREwire Study (NCT02935088), a registered phase not stated study. The primary outcome is Number of Subjects With 12 Month Clinical Outcomes (MACE) Major Adverse Cardiac Events by FFR Values and Resting Indices.

2. Clinical Question

3. Trial Design

PRESSUREwire Study (NCT02935088) is titled Practical Evaluation of Fractional Flow Reserve (FFR) and Its Associated Alternate Indices During Routine Clinical Procedures. The registry record describes a study of routine clinical use rather than a randomized comparison. It states that the purpose is to understand how FFR and alternate indices are used in practice and to determine clinical outcomes in patients presenting with stable coronary artery disease or acute coronary syndrome. The description includes culprit and non-culprit lesions and index and secondary procedures.

The listed intervention is Fractional Flow Reserve, classified as a device. Enrollment was 2217. The record identifies FFR-guided PCI patients in the adverse-event information, but does not describe a separate control arm. Allocation is not stated, and the registry record explicitly does not identify a randomized comparison. Therefore, the listed cohort information should not be interpreted as a treatment-versus-control contrast.

The study started on 2016-10-12, had a primary completion date of 2019-03-22, and is marked COMPLETED. The sponsor is Abbott Medical Devices. Six outcome measures are listed, while no analyses are listed in the registry record. The registry record does not report the detailed recruitment process, eligibility criteria, follow-up procedures, investigator blinding, protocol deviations, or a full statistical analysis plan. Those details should not be inferred from the completed status or the study’s stated purpose.

The primary measure concerns participants with 12-month MACE, and the planned analysis evaluates association with binary FFR variables using Fisher’s exact test. This describes the intended endpoint analysis, not evidence that a particular association was found. The registry record does not report the primary outcome counts or a conclusion from that analysis.

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

Analysis population for the primary outcome, as defined in the registry: The denominators used in the calculations of adverse event rates will be determined according to the analysis population excluding subjects who are lost to follow-up through given time point without events.

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 Number of Subjects With 12 Month Clinical Outcomes (MACE) Major Adverse Cardiac Events by FFR Values and Resting Indices, measured over 12 months.

The primary endpoint is the number of participants with major adverse cardiac events over 12 months. MACE is defined as a composite of all-cause death, documented non-fatal myocardial infarction, and unplanned hospitalization leading to urgent revascularization. A composite endpoint combines several clinically consequential event types into a single outcome for analysis. Its interpretation depends on the definition of each component and on how the combined outcome is counted.

The registry record states that MACE will be evaluated in relation to binary FFR variables, distinguishing low FFR (FFR ≤ 0.8) from high FFR (FFR > 0.8). This makes the endpoint useful for asking whether the observed 12-month event outcome is associated with the recorded FFR category. It does not, by itself, establish that FFR category caused an event or that one clinical strategy is better than another.

The record specifies that adverse-event rate denominators exclude participants lost to follow-up through the relevant time point without events. It does not report the primary endpoint counts by FFR category, the number included in each analysis denominator, or the resulting event rates. The outcome definition and analysis plan are reported, but the primary endpoint result is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What kind of outcome is being analyzed?

The primary endpoint is binary at the participant level: a participant either meets the stated MACE definition during the 12-month period or does not. The registry describes the outcome as the number of participants with MACE. A count is not the same as an event rate. To interpret a rate, the numerator must be considered alongside the relevant analysis denominator. The record says that denominators for adverse-event rates exclude people lost to follow-up through the time point without events, but it does not report the actual primary-outcome denominators or counts.

In general, a binary outcome makes it possible to compare the occurrence of an event across categories. Here, the planned categories are low FFR (FFR ≤ 0.8) and high FFR (FFR > 0.8). These are measurement groups, not randomized arms. The study description concerns routine practice, so differences between categories may coexist with differences in patient characteristics, clinical presentation, lesion selection, or treatment decisions. The registry record does not report analyses adjusting for such differences.

Why is Fisher’s exact test named?

The endpoint description states that Fisher’s exact test will evaluate the association between 12-month MACE and binary FFR variables. In general, Fisher’s exact test evaluates whether the distribution of a binary outcome differs across categories in a two-by-two arrangement. It calculates a probability for the observed arrangement under a null hypothesis of no association, conditional on the table margins. It does not estimate a causal effect, remove confounding, or explain why an association might occur.

The registry record names the test but does not report its result. No test statistic, p-value, confidence interval, or group-specific outcome count is reported in the registry record. The record also does not clarify whether the planned test was applied to every listed FFR variable or how any multiple comparisons were handled.

What would an estimate and confidence interval convey?

In general, an effect estimate describes the size and direction of a contrast or association. A confidence interval describes the range of values compatible with the data and the method’s assumptions, and indicates the precision of the estimate. A narrow interval generally conveys greater precision than a wide interval, but neither an estimate nor its interval can be interpreted without knowing the analysis population, outcome definition, and comparison being made.

No primary MACE effect estimate or confidence interval is reported in the registry record. It is therefore not possible to describe the magnitude or precision of the planned association. A p-value, even if it were reported, would not by itself convey the size or clinical importance of an association. No p-value for this endpoint is reported in the registry record.

How should the planning illustrations be read?

The sample-size assumptions describe planning illustrations based on the observed effect, not the trial’s own design. They use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. These assumptions are hypothetical illustrations and should not be treated as the study’s original sample-size justification. That justification is not reported in the registry record.

In general, a sample-size calculation describes how many participants would be needed under specified assumptions to target a chosen level of statistical power for a particular effect. It is sensitive to the assumed effect and analysis method. An illustration based on a fraction of an observed effect explores how a different target effect would affect planning; it does not establish what effect was present or what power the completed study achieved. Sample-size calculations are not observed power. No numerical illustration values or primary effect estimate are reported in the registry record.

What can be concluded about model choice and precision?

The named primary method is a categorical association test, not a regression model. The record does not report covariate adjustment, subgroup modeling, time-to-event analysis for MACE, or methods for handling repeated measurements. In general, adjustment can address measured differences under the chosen model, but cannot guarantee that unmeasured differences are removed. The method information available is not enough to determine whether additional analyses were conducted.

General statistical caution also applies to event counts: estimates based on fewer observed events tend to be less precise, and sparse cells can make some asymptotic approximations unreliable. Fisher’s exact test is commonly used for categorical counts when exact inference is appropriate. These are general points, not claims about the distribution of PRESSUREwire events. The registry record does not provide the cross-tabulation needed to assess cell sizes or precision.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists six outcome measures and no analyses. It names Fisher’s exact test for the primary MACE association, but does not report a complete analysis plan, the full set of planned hypotheses, or whether any multiplicity adjustment was intended. When multiple outcomes, subgroup comparisons, or repeated tests are considered, the chance of at least one nominally unusual result can increase. In general, a prespecified testing strategy and any adjustment approach help readers understand how such results should be interpreted. The registry record does not report those details.

The primary endpoint description gives a denominator rule for adverse-event rates: participants lost to follow-up through the given time point without events are excluded. The number lost to follow-up, the number excluded, and the denominator used for the primary MACE analysis are not reported in the registry record. The record does not describe imputation, sensitivity analyses for missing outcomes, or other methods for assessing the impact of incomplete follow-up.

The analysis population is described only in that denominator rule. Further definitions, such as whether all enrolled participants were eligible for each analysis or how participants with incomplete FFR information were handled, are not reported in the registry record. The record also does not report interim analyses, stopping rules, or a detailed protocol for outcome adjudication. These omissions limit assessment of the analysis choices and the potential effect of missing data or multiple testing. They do not establish that any particular method was or was not used outside the registry record.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cardiac disorders (3.2%), general disorders (0.5%), cancer (0.4%), vascular disorders (0.3%), pneumonia (0.2%).

The adverse-event information describes a group titled FFR-guided PCI Patients. It lists 2217 participants at risk for serious adverse events and 107 serious adverse events; for other adverse events it lists 2217 at risk and 114 events. The record also lists 50 deaths. These are the posted safety figures, and they are distinct from the unreported primary MACE counts by FFR category.

The serious-event categories listed with percentages are cardiac disorders (3.2%), general disorders (0.5%), cancer (0.4%), vascular disorders (0.3%), pneumonia (0.2%), and gastrointestinal disorders (0.2%). These categories should be read as registry safety classifications, not as a complete explanation of the clinical circumstances. The record does not report category-specific counts, definitions, coding rules, or whether a participant could appear in more than one category.

In general, an at-risk denominator gives context for an event count, but interpretation also depends on the reporting window, whether the entry represents people or events, and how repeated events are handled. Those details are not reported in the registry record. The figures alone do not establish that an event was caused by the device or procedure, and they do not provide a comparison with an untreated or randomized control group.

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

The posted information establishes the study’s focus, enrollment, primary outcome definition, and intended test of association. It also gives a limited set of safety counts and serious-event categories. It does not report the primary 12-month MACE counts by FFR group, event rates, an effect estimate, a confidence interval, or a test result. The primary clinical outcome question therefore cannot be answered from the registry record as posted.

The study description is relevant to routine use of FFR and alternate indices during clinical procedures, and it includes patients with stable coronary artery disease or acute coronary syndrome. The endpoint brings together all-cause death, documented non-fatal myocardial infarction, and unplanned hospitalization leading to urgent revascularization. The record’s focus on this composite does not show how often each component occurred or which component, if any, accounted for a combined result.

The low and high FFR categories define the planned association question, but they do not constitute randomized treatment groups. The record does not state allocation or report a like-for-like control comparison. Even if category-specific results were available, an unadjusted association would not by itself establish a causal effect of FFR-guided care. The registry record does not report an adjusted estimate or the information needed to assess confounding.

The safety figures describe reported adverse events in the FFR-guided PCI group. They do not supply a treatment comparison, establish causation, or substitute for the primary endpoint analysis. Similarly, a completed registry status does not mean that the outcome results are included in the record. The statistical meaning is therefore bounded: the registry describes what was intended to be assessed and some safety reporting, but does not report the primary clinical outcome findings needed to quantify an association.

13. Why This Trial Matters Statistically

This study raises a statistical question that matters for interpreting routine clinical data: how are measured physiological indices associated with subsequent outcomes when measurement and care occur in practice? The registry describes assessment of FFR and alternate indices in stable coronary artery disease and acute coronary syndrome, across culprit and non-culprit lesions and index and secondary procedures. Such settings can involve variation in patient characteristics and clinical decisions, making careful separation of description, association, and causal inference important.

The primary endpoint combines several serious outcomes over 12 months. A composite can provide a single summary for analysis, but its meaning depends on the components, their definitions, and their individual contributions. The record defines the composite but does not report component counts or the primary group-specific results. That gap prevents a reader from judging either the size of the association or what events drive it.

The planned Fisher exact test provides a direct way to assess a categorical association, but it does not control for differences between FFR groups. Because the registry does not describe randomized allocation, the comparison should not be understood as an experimental treatment contrast. This distinction is central when translating routine-practice evidence into statistical claims.

Finally, the record illustrates why registration details and outcome reporting are both needed. It identifies enrollment, the endpoint, and a test, yet does not provide the primary results or details needed to evaluate missing data and multiplicity. Without estimates and their precision, readers cannot judge the magnitude of the association or its uncertainty. The statistical importance lies in recognizing both the useful clinical question and the limits of what the registry record reports.

14. 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.

Several limitations follow directly from the registry information. The primary MACE result is not reported: there are no outcome counts by FFR category, rates, effect estimates, confidence intervals, or test results. The six listed outcome measures are not accompanied by analysis results, and no analyses are listed. This prevents assessment of the primary association and the precision of any estimate.

The record does not describe a randomized comparison, and allocation is not stated. The adverse-event entry identifies FFR-guided PCI patients but does not provide a like-for-like control group. Consequently, the listed safety information cannot support a comparative treatment conclusion. The registry record also does not report adjustment for baseline differences, a detailed analysis population, or handling of missing FFR measurements.

Although the endpoint definition is stated, the record does not provide component-specific MACE counts or enough information to assess the contribution of death, non-fatal myocardial infarction, and urgent revascularization. The denominator rule excludes those lost to follow-up without events, but the number lost and the resulting primary analysis denominator are not reported. Missing-data methods and sensitivity analyses are not reported in the registry record.

Safety reporting is also limited by absent definitions for the event-count fields, reporting windows, category coding, and overlap. The serious-event percentages are listed without category-specific counts or denominator details. The record does not report the detailed protocol, eligibility criteria, interim analyses, multiplicity approach, or a full statistical analysis plan. These limitations restrict interpretation; they do not establish what analyses may have been conducted outside the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: PRESSUREwire Study — NCT02935088.
• Registry record last updated 2020-02-07; status last verified 2020-01.
• Results first posted 2020-02-07.
• 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.

18. Record Summary

PRESSUREwire Study (NCT02935088), sponsored by Abbott Medical Devices, is marked COMPLETED. It enrolled 2217 participants and studied routine use of FFR and alternate indices in clinical practice. The listed intervention is Fractional Flow Reserve, classified as a device. The study concerns stable coronary artery disease and acute coronary syndrome, including culprit and non-culprit lesions and index and secondary procedures.

The primary measure is the number of participants with 12-month MACE, defined as all-cause death, documented non-fatal myocardial infarction, or unplanned hospitalization leading to urgent revascularization. The stated analysis uses Fisher’s exact test to evaluate association with binary FFR groupings. Primary endpoint results are not reported in the registry record. Six outcome measures are listed, and no analyses are listed.

The adverse-event record lists 107 serious events, 114 other events, and 50 deaths among the FFR-guided PCI patients, with 2217 at risk for each adverse-event category. The record does not identify a randomized comparison or state allocation.