Tailored Antiplatelet Therapy Following PCI: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Tailored Antiplatelet Therapy Following PCI (NCT01742117), a randomized phase 4 study. The primary outcome is Occurrence of the a Major Adverse Cardiovascular Event in Subjects Identified as CPY2C19 LOF Carriers by TaqMan..

2. Clinical Question

The study addresses whether genetic information can guide antiplatelet treatment after coronary stent placement for people who may have reduced clopidogrel response. The registry summary describes the rationale as a concern that CYP2C19 variation can affect clopidogrel activation, while ticagrelor is not dependent on that enzyme for activation. That background explains the treatment strategy being examined; it does not establish the comparative result.

The reported primary endpoint is a count of participants with an event, not a measure of event severity or time until an event. The comparison is restricted to identified LOF carriers rather than all participants enrolled in the trial. The registry record does not report a separate primary result for the full randomized population.

3. Trial Design

TAILOR-PCI was a randomized, open-label, parallel-group, phase 4 study sponsored by Mayo Clinic. The registry lists enrollment of 5276 and a completed status. The study began in 2013-05, and the primary completion date is 2020-10-31. Participants were assigned to genotype-guided therapy or conventional therapy; masking is listed as none.

In the genotype-guided group, participants were genotyped prospectively for CYP2C19 *2, *3 and *17 alleles, and treatment was based on genotype. The arm description identifies *2 and *3 as reduced-function alleles. In the conventional group, participants received clopidogrel once daily after the index PCI, with genotyping performed retrospectively after completion of one year of clopidogrel treatment. Although the record lists clopidogrel and ticagrelor as interventions, the full genotype-specific treatment assignment is not reported in the registry record.

The primary endpoint timeframe was one year after PCI. The analysis population was narrower than total enrollment: 903 participants in the genotype-guided arm and 946 in the conventional arm contributed to the posted primary endpoint counts. The endpoint description says 1738 participants in the genotype-guided arm were excluded because they were identified as noncarriers or had no TaqMan result, and 1689 in the conventional arm were excluded because they were identified as noncarriers. The displayed endpoint denominators therefore describe the analyzed carrier groups, not all randomized participants.

The registry also lists two bleeding outcomes: one among identified LOF carriers at one year and one across the study groups at approximately 3 years after PCI. The original protocol's sample-size justification, planned interim analyses, detailed allocation procedures and full statistical analysis plan are not reported in the registry record. The record lists randomization but does not provide further detail about its implementation.

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: For 1 year endpoint in Genotype-Guided Therapy arm 1738 were excluded from data analysis due Identified as CYP2C19 LOF noncarriers by TaqMan or no TaqMan results available. For 1 year endpoint in Conventional Therapy arm 1689 were excluded from data analysis due Identified as CYP2C19 LOF noncarriers by TaqMan or no TaqMan results available.

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 Occurrence of the a Major Adverse Cardiovascular Event in Subjects Identified as CPY2C19 LOF Carriers by TaqMan., measured over 1 year after percutaneous coronary intervention (PCI).

The primary endpoint counts participants who experienced at least one major adverse cardiovascular event within one year after PCI. The registry defines the composite as cardiovascular death, myocardial infarction, stroke, severe recurrent ischemia or stent thrombosis. It is reported as a participant count in each analysis group, so the outcome is whether a participant experienced an event during the stated timeframe, rather than the number of separate events per participant.

A composite endpoint combines clinically distinct outcomes into one measure. In general, this can capture a broader range of adverse cardiovascular events than any single component and can increase the number of participants contributing an endpoint event. Its interpretation depends on the components: the overall result does not establish that each component changed in the same way, or that one component drove the composite. Component-specific primary results are not reported in the registry record.

The endpoint is evaluated among participants identified as CYP2C19 LOF carriers by TaqMan. This focuses the primary question on the group for whom genotype-guided treatment was intended to be relevant, but it also means the result does not directly describe the full enrolled population. The registry's exclusion notes identify participants without an available TaqMan result as well as identified noncarriers among the genotype-guided exclusions. The endpoint counts and denominators should therefore be read as results for the posted analysis population, not as counts for everyone enrolled.

7. Results Posted in the Registry

• Conventional Therapy: 5.7% (54/946) versus 3.9% (35/903) on control; risk difference 1.8 percentage points (95% CI -0.1 to 3.8), risk ratio 1.47 (0.97–2.23); unadjusted two-proportion z-test p = 0.066.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Thrombolysis in Myocardial Infarction Major or Minor Bleeding in Subjects Identified as CPY2C19 LOF Carriers by TaqMan.

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Conventional Therapy: 1.5% (14/946) versus 1.8% (16/903) on control; risk difference -0.3 percentage points (95% CI -1.4 to 0.9), risk ratio 0.84 (0.41–1.70); unadjusted two-proportion z-test p = 0.619.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Conventional Therapy and the control. The interval gives the range of effects that remain compatible with the data.

Thrombolysis in Myocardial Infarction Major or Minor Bleeding

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Conventional Therapy: 2.0% (53/2635) versus 2.0% (54/2641) on control; risk difference -0.0 percentage points (95% CI -0.8 to 0.7), risk ratio 0.98 (0.68–1.43); unadjusted two-proportion z-test p = 0.932.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Conventional Therapy and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary outcomes cover TIMI major or minor bleeding among identified CYP2C19 LOF carriers at one year and bleeding across the study groups at approximately 3 years after PCI. Across these endpoints, the observed group counts are close in absolute terms, and the unadjusted confidence intervals include the null values. The results therefore do not provide a clear, precise separation between the treatment groups on these bleeding measures.

These outcomes complement the primary cardiovascular endpoint by addressing bleeding rather than the primary composite of cardiovascular death, myocardial infarction, stroke, severe recurrent ischemia and stent thrombosis. They should be considered alongside, not substituted for, the primary result. The secondary data do not resolve the uncertainty in the primary comparison or establish that the treatment strategies have equivalent effects across all outcomes.

Unadjusted secondary results carry less weight when several outcomes are examined because the chance of finding an apparently notable result can increase across multiple comparisons. A prespecified multiplicity strategy can address that issue, but one is not reported in the registry record. The registry also lists no reported analyses for these secondary outcomes. Accordingly, the secondary comparisons are descriptive and should not be treated as confirmatory evidence independent of the primary endpoint.

The endpoint populations and timeframes also differ: one bleeding measure is limited to identified carriers and one year, while the other includes the broader study groups at approximately 3 years. These outcomes are not direct replications of the primary endpoint. Their interpretation should retain the distinctions in population, outcome and follow-up period, and should avoid drawing a single overall treatment conclusion from a collection of unadjusted estimates.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Thrombolysis in Myocardial Infarction Major or Minor Bleeding in Subjects Identified as CPY2C19 LOF Carriers by TaqMan.
• Thrombolysis in Myocardial Infarction Major or Minor Bleeding

9. Statistical Interpretation

10. Statistical Methods Explained

General: Comparing binary outcomes. The primary endpoint is binary at the participant level: each person either experienced at least one event during the specified timeframe or did not. For this type of outcome, group event proportions can be compared using an absolute measure, such as a risk difference, or relative measures, such as a risk ratio or odds ratio. These measures answer different questions. A risk difference expresses the contrast in event proportions; a risk ratio compares those proportions as a ratio; an odds ratio compares event odds. They are not interchangeable, particularly when an outcome is not rare.

For the primary endpoint, the posted risk difference is 0.018 for conventional therapy relative to genotype-guided therapy. The corresponding risk ratio is 1.473 and the odds ratio is 1.501. The direction of each estimate reflects the greater observed event proportion in the conventional group, but each estimate is uncertain. These comparisons are unadjusted and are based on the counts and denominators reported for the carrier analysis population.

General: Confidence intervals. A confidence interval describes a range of values compatible with the data and the method used to construct the interval. It indicates estimation uncertainty; it is not a range containing a known true effect with certainty, nor is it a statement about the probability that a particular treatment is superior. For a risk difference, zero is the null value of no difference. For a risk ratio or odds ratio, one is the null value. The primary intervals include their respective null values, so the results do not rule out no difference under the reported unadjusted comparisons.

General: P-values. A p-value assesses how surprising data at least as extreme as the observed data would be under a specified null model and its assumptions. It does not measure clinical importance, the chance that the null hypothesis is true, or the probability that the observed result is due to chance. The primary unadjusted p-value is 0.066. The registry record does not provide details of a sponsor-reported adjusted analysis, multiplicity procedure or prespecified decision rule, so the p-value should be interpreted as an unadjusted result rather than as evidence that all analysis choices were accounted for.

General: Randomization and analysis population. Random assignment is intended to make treatment groups comparable on average at the point of assignment. It does not ensure that all participants remain in every endpoint analysis or that post-randomization exclusions are inconsequential. Here, the primary result uses the identified LOF-carrier groups, with endpoint exclusions described in the registry. Because the displayed analysis population is smaller and more specific than total enrollment, its interpretation depends on how carrier status and missing TaqMan results were handled. The registry record does not report enough detail to assess the full analysis-population strategy, the handling of missing endpoint data, or whether the primary result followed an intention-to-treat approach.

General: Composite endpoints. Combining multiple event types can summarize a broader clinical question, but a composite can conceal different patterns among its components. A similar overall composite result could arise from consistent changes across components or from a pattern concentrated in one component. The registry defines the components, but does not report component-specific primary comparisons. It is therefore not possible to identify from the posted primary result which component contributed most to the count.

General: Recalculation and reported analyses. The comparison measures posted with the counts are unadjusted. The registry lists no reported analyses for the secondary endpoints. No additional model, covariate adjustment, stratification or sensitivity analysis should be inferred from the counts alone. The registry record does not report the full statistical analysis plan or the trial's original sample-size justification. Those omissions limit assessment of whether the posted analyses align with the original prespecified plan.

General: Over-dispersion and outcome types. Over-dispersion arises when observed variability exceeds what a particular statistical model assumes. It is important for outcomes measured as counts or rates, because underestimated variability can make intervals too narrow and tests too optimistic. The posted outcomes are participant counts with a binary event status, and the record does not report a dispersion estimate or an over-dispersion adjustment. No conclusion about such a model adjustment can be drawn from the registry record.

General: Statistical and practical interpretation. Statistical evidence and practical importance are different considerations. A small p-value alone would not establish that an effect matters, and an interval including the null does not establish equivalence. Equivalence or noninferiority requires a defined margin and an analysis designed for that question. Such a margin and a noninferiority or equivalence analysis are not reported in the registry record. The appropriate reading is to describe the estimate, its interval, the analysis population and the limits of the posted evidence without converting a nonsignificant test into a claim of sameness.

11. Confidence Intervals and Precision

The primary risk-difference estimate is 0.018, with a 95% confidence interval from -0.001 to 0.038. The interval includes zero, the value corresponding to no absolute difference. It also extends in the direction of a higher observed risk in the conventional-therapy group. Thus, the estimated contrast is not precise enough to distinguish confidently between little or no difference and a larger positive difference within the interval.

The relative measures have a similar uncertainty. The risk ratio is 1.473, with a 95% confidence interval from 0.972 to 2.231; the odds ratio is 1.501, with a 95% confidence interval from 0.971 to 2.321. Each interval includes one, the null value for a ratio. The estimates point in the same direction as the risk difference, but the intervals allow a range of possible relative effects.

Confidence intervals are not proof that every value inside them is equally plausible, and they do not measure the chance that the result will replicate. They summarize uncertainty under the method used. The registry record does not report details about the interval-construction method or an adjusted interval for the primary result. The displayed precision should therefore be understood as applying to the posted unadjusted comparison in the identified carrier population.

The analyzed group sizes are 903 in the genotype-guided arm and 946 in the conventional arm, while the trial enrollment is 5276. The difference in scope matters: precision for the carrier analysis is not the same as precision for an analysis of all randomized participants. The registry's exclusion notes also identify missing TaqMan results in the genotype-guided group. The consequences of missing results for selection and uncertainty are not quantified in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning illustrations are expressed as participants per arm for each binary endpoint. They are not total events. The primary endpoint illustrations use the observed effect as a planning reference and show participant requirements for detecting 100% of that observed effect, 75% of the observed effect and 50% of the observed effect. At each effect level, the figures are given separately for 80% power and 90% power. For example, planning for 100% of the observed primary effect gives 2,133 participants per arm for 80% power and 2,854 participants per arm for 90% power. These are planning illustrations, not the original trial's design targets.

The assumptions for these illustrations are a two-sided significance level of 0.05, equal allocation between the two arms and a normal approximation. The effect to detect is the stated fraction of the observed effect. The registry record does not report the trial's original sample-size assumptions or justification. The illustrations for the bleeding outcomes are likewise participants per arm; they should not be mistaken for counts of bleeding events.

In general, 80% power describes the probability of detecting an effect of the specified size under the assumptions if that effect is present; 90% power uses a higher target probability. Achieving the higher target generally requires more participants under otherwise similar assumptions. Smaller effects also require more participants to detect reliably, which is why the planning figures rise when planning for a smaller fraction of the observed effect.

These calculations are planning illustrations based on observed effects, not observed power. Observed power is not a useful substitute for interpreting the effect estimate and its confidence interval. The trial's actual enrollment and its primary endpoint analysis population are reported separately from these hypothetical planning figures.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.039; treatment proportion p₁ = 0.057; average p̄ = 0.048.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.3021 = 0.5921.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.3018 = 0.2540.
4. n = (0.5921 + 0.2540)² / (0.0183)² = 2,132.1, rounded up to 2,133 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.0387596899224806                          # control proportion
p1 <- 0.0570824524312896                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1742117)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 2,133 (80% power), 2,854 (90% power)
 75% of observed effect: n per arm = 3,619 (80% power), 4,845 (90% power)
 50% of observed effect: n per arm = 7,754 (80% power), 10,380 (90% power)
power.prop.test: 2132.1 
Simulated power at n = 2,133 per arm: 0.803 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record does not report a multiplicity adjustment, a hierarchy for testing the primary and secondary outcomes, or a prespecified strategy for controlling the chance of false-positive findings across comparisons. This matters because the study lists a primary cardiovascular endpoint and secondary bleeding endpoints, and multiple results can generate a broader set of statistical tests. Without a reported plan, the secondary p-values should be treated as unadjusted and exploratory rather than as confirmatory findings.

The primary endpoint is described among identified CYP2C19 LOF carriers. The record notes that 1738 participants in the genotype-guided arm were excluded from the one-year endpoint analysis because they were identified as LOF noncarriers or had no TaqMan result available; 1689 participants in the conventional arm were excluded because they were identified as LOF noncarriers. The analyzed counts are 903 and 946, respectively. These exclusions define the population represented by the posted primary result.

The registry record does not explain in detail how missing TaqMan results were handled beyond the exclusion note, whether endpoint status was missing for any analyzed participant, or whether missing data were imputed. It also does not report a complete accounting of participants by randomized arm for the primary analysis, reasons for all exclusions, or sensitivity analyses assessing the effect of missing data. Those details are important when judging whether the analyzed carrier groups remain comparable after exclusions.

Randomization supports comparison of assigned groups, but a subgroup analysis based on genotype and available testing can have a different interpretation from a full randomized-population analysis. The registry record does not report whether the carrier subgroup was prespecified for the primary analysis, the exact analysis population principle, or adjusted analyses accounting for relevant covariates. The original statistical analysis plan and interim-analysis approach are also not reported in the registry record. As a result, the posted estimates can be described, but these gaps limit evaluation of prespecification, missing-data sensitivity and the full inferential context.

15. 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.

The registry lists serious adverse event figures for 2641 participants at risk in the genotype-guided group and 2635 in the conventional-therapy group. It records 0 serious adverse events in each group and 0 other adverse events in each group. The record also lists 95 deaths in the genotype-guided group and 98 in the conventional group.

These figures should be read as the adverse-event counts reported in the registry record, not as a detailed safety comparison. The record does not provide serious-event terms, and the list of top serious adverse-event terms is empty. It also does not specify in the posted figures how deaths relate to the adverse-event categories, their causes, timing, or attribution to treatment. The at-risk counts used for these safety entries differ from the denominators in the primary carrier analysis, so they describe a broader population than the one-year primary endpoint result.

Zero events recorded in a category do not, by themselves, establish that no event occurred outside the registry's reporting definitions or collection period. The registry record does not report further detail on event ascertainment or follow-up for these safety figures. The counts therefore offer a limited description and should not be read as a complete comparative safety assessment.

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

The posted primary data show that major adverse cardiovascular events were counted in both analyzed carrier groups during the year after PCI. The unadjusted point estimate is in the direction of more events in the conventional-therapy group, but the confidence interval for the risk difference includes no difference. The p-value is 0.066, and the ratio estimates also have confidence intervals that include their null values. These results leave uncertainty about the size and direction of the underlying difference.

This is not evidence that the strategies are equivalent. Demonstrating equivalence or noninferiority requires a prespecified margin and a suitable analysis; neither is reported in the registry record. Nor does the unadjusted result establish that genotype-guided therapy is superior. The appropriate interpretation is limited to the posted comparison and its precision.

The primary analysis applies to identified CYP2C19 LOF carriers, not to the full randomized population. Its one-year composite includes five types of cardiovascular events, and the registry does not report separate primary comparisons for those components. The reported result cannot identify whether individual components had similar or different patterns. It also does not answer questions about outcomes beyond the specified timeframe.

The trial record lists secondary bleeding endpoints with different populations and follow-up periods. Those results are unadjusted and do not supply a definitive overall account of the balance of cardiovascular and bleeding outcomes. The record does not report a multiplicity strategy, the complete analysis plan or the original sample-size justification. Such omissions do not invalidate the displayed counts, but they constrain how much can be concluded from the registry results alone.

In general, statistical estimates describe patterns in observed data; they do not determine an individual patient's treatment choice. The registry result should be understood as an estimate for the stated study population and endpoint, with uncertainty and reporting limitations, rather than as medical advice or a universal treatment conclusion.

17. Why This Trial Matters Statistically

This trial raises a clear statistical question about treatment assignment guided by genetic information: whether the event count differs between genotype-guided and conventional approaches among people identified as CYP2C19 LOF carriers. The design distinguishes prospective genotype-guided care from conventional clopidogrel treatment with retrospective genotyping, while the primary endpoint focuses on a defined one-year composite.

Its results illustrate why an estimate, a confidence interval and a p-value should be read together. The risk-difference point estimate favors a lower observed event proportion in the genotype-guided group, but its interval includes zero and the unadjusted p-value is 0.066. That combination is not a demonstration of no effect, and it is not proof of a treatment advantage. It communicates that the observed contrast is uncertain at the precision reported.

The analysis also illustrates the importance of population definition. Total enrollment is 5276, while the primary endpoint result is based on smaller identified-carrier groups. Exclusions based on carrier status and TaqMan availability make the primary analysis population distinct from all randomized participants. Statistical interpretation depends on understanding exactly who contributed to the endpoint counts.

Finally, the registry record highlights the value of prespecified analysis plans and transparent reporting. Details about the original sample-size justification, multiplicity, missing-data handling and adjusted analyses are not reported. Without those details, readers can interpret the posted estimates and their uncertainty, but cannot fully assess how the analyses relate to the trial's original statistical plan. The sample-size illustrations offer planning context, not evidence about the trial's observed power.

18. 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 primary result is restricted to participants identified as CYP2C19 LOF carriers by TaqMan. The registry describes exclusions among participants who were noncarriers and, in the genotype-guided group, those with no TaqMan result available. The record does not give enough detail to assess the impact of missing genotype results on selection into the analyzed population or to determine how such missingness was handled beyond the stated exclusions.

The posted primary comparison is unadjusted. The registry record does not report a full statistical analysis plan, covariate-adjusted estimates, sensitivity analyses, a multiplicity strategy or a detailed missing-outcome-data approach. It also does not report the original sample-size justification or interim-analysis plan. These gaps limit evaluation of prespecification and robustness, rather than changing the arithmetic of the posted counts.

The primary endpoint combines cardiovascular death, myocardial infarction, stroke, severe recurrent ischemia and stent thrombosis. Component-specific primary estimates are not reported, so the overall composite cannot show which event types contributed to the group counts. The registry also does not provide a detailed genotype-specific treatment assignment for the genotype-guided arm, despite listing clopidogrel and ticagrelor as interventions.

Secondary bleeding endpoints differ in analysis population and timeframe and are listed without reported analyses. The safety entries provide counts but little detail about event terms, timing, attribution or ascertainment. These limits mean the registry results should be interpreted as a focused statistical description of the posted outcomes, not as a complete assessment of every clinical endpoint or analysis from the trial.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Tailored Antiplatelet Therapy Following PCI — NCT01742117.
• Registry record last updated 2021-11-09; status last verified 2021-10.
• Results first posted 2021-11-09.
• 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.

22. Record Summary

TAILOR-PCI is a completed, randomized, open-label, parallel-group phase 4 trial sponsored by Mayo Clinic, with enrollment of 5276. It compared prospective genotype-guided antiplatelet therapy with conventional clopidogrel after PCI. The primary endpoint was a one-year major adverse cardiovascular event composite among identified CYP2C19 LOF carriers.

The primary event counts were 35 of 903 participants with genotype-guided therapy and 54 of 946 with conventional therapy. The unadjusted risk difference was 0.018, with a 95% confidence interval from -0.001 to 0.038 and p = 0.066. The interval includes no difference, so the posted result remains uncertain. Secondary bleeding outcomes and limited safety counts are also listed. The registry record does not report the full analysis plan, original sample-size justification, multiplicity approach or detailed missing-data methods.