Topical Nitroglycerine Treatment for Radial Artery Spasm Prevention: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Topical Nitroglycerine Treatment for Radial Artery Spasm Prevention (NCT02832115), a randomized phase 4 study. The primary outcome is Radial Artery Spasm.

2. Clinical Question

The primary outcome was intraprocedural and used a composite score: a participant was counted as having spasm when the score was 1 or more. The score combined forearm pain aggravated by catheter or sheath movement, difficulty manipulating the catheter, difficulty removing the sheath, and additional intra-arterial nitroglycerine or verapamil after the initial vasodilator cocktail. The registry also lists changes in radial artery dimension, procedural failure, pain or discomfort, and radial pulse at the end of the procedure as secondary outcomes.

3. Trial Design

The registry describes a randomized, double-blind, parallel-group, placebo-controlled Phase 4 study conducted at a single center. The two preparations shared topical lidocaine; the study preparation added nitroglycerine, while the control preparation used placebo. The study preparation contained 40 mg of lidocaine and 30 mg of nitroglycerine, and the control contained 40 mg of lidocaine. Both were applied over the radial pulse at least 60 minutes before arterial puncture. The registry says the preparations were removed immediately before sterile preparation of the access site.

The registry lists an enrollment of 100 and a status of completed. The recorded start is 2016-09, and the primary completion date is 2019-05-02. The stated clinical context is transradial coronary angiography and intervention, with the main objective of assessing radial artery spasm. The description also names patient comfort and post-procedure radial artery patency as objectives, while the posted secondary outcomes include pain or discomfort and radial pulse at the end of the procedure.

The registry’s primary outcome data use 48.0 participants in the study arm and 52.0 in the control arm. Other outcome denominators differ: the radial artery dimension measure uses 42.0 and 45.0, while pain uses 48.0 in each arm. Reasons for these differences are not reported in the registry record. Randomization and double masking describe the planned comparison, but the registry record does not report the randomization procedure, allocation concealment details, how masking was maintained, or whether masking was assessed. The original trial’s sample-size rationale and statistical analysis plan are not reported in the registry record.

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 Radial Artery Spasm, measured over Intraprocedural: From procedure start to application of radial band. Approximate time 30 to 90 minutes..

The primary endpoint was the incidence of radial artery spasm during the procedure, from procedure start to application of the radial band. The stated approximate observation period was 30 to 90 minutes. A participant counted as having the event if the radial artery spasm score was 1 or more. The score added indicators for intraprocedural forearm pain aggravated by movement of the catheter or sheath, difficulty manipulating the catheter, difficulty removing the sheath, and additional intra-arterial nitroglycerine or verapamil after the initial vasodilator cocktail.

This composite endpoint brings together symptoms, technical difficulty, and additional treatment into a single event indicator. That approach can capture more than one manifestation of spasm, but it also means that participants can meet the endpoint through different combinations of score components. The posted results give the overall number of participants meeting the threshold, not component-specific counts. The registry record does not report component-level results, adjudication procedures, or a separate measure of spasm severity.

As a binary endpoint, the measure is expressed as participants with the event rather than as a continuous score. Comparing the proportions describes the observed difference in event frequency between randomized arms. The measure is relevant to the stated procedural question, but it does not by itself establish which component drove any difference, or whether a recorded event had a particular clinical consequence.

7. Results Posted in the Registry

• Study: 16.7% (8/48) versus 28.8% (15/52) on control; risk difference -12.2 percentage points (95% CI -28.4 to 4.0), risk ratio 0.58 (0.27–1.24); unadjusted two-proportion z-test p = 0.148.

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.

Change in Radial Artery Dimension Measured in mm^2.

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Study: mean 2.50 versus -0.20 on control; difference 2.70 (95% CI 2.11 to 3.29), standardized effect d = 1.95; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Study than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Number of Patients With Procedural Failure

• 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:
  • Study: 0.0% (0/48) versus 7.7% (4/52) on control; risk difference -7.7 percentage points (95% CI -14.9 to -0.4); unadjusted two-proportion z-test p = 0.050.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for Study than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Patient Discomfort or Pain During Procedure (Visual Analog Scale 0-10)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Study: mean 0.79 versus 0.88 on control; difference -0.08 (95% CI -0.88 to 0.72), standardized effect d = -0.04; z-test p = 0.839.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Study and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover different aspects of the procedure: artery dimension, procedural failure, pain or discomfort, and radial pulse at the end of the procedure. The posted data do not give a uniform pattern across these measures. The dimension comparison points in the study arm’s direction, the procedural-failure count is lower in that arm, and the pain comparison is close in its observed arm means. The radial pulse result is not reported in the registry record. These measures are related to the broader procedural objectives, but none is identical to the primary composite spasm endpoint.

This pattern can add context to the primary result, but it does not resolve the uncertainty around the primary comparison. For example, a change in artery dimension is not the same outcome as meeting the composite spasm threshold, and procedural failure is a separate event. Concordance or discordance among outcomes can inform interpretation, but the secondary measures cannot be treated as direct replications of the primary endpoint. The registry does not report component-level spasm results that would connect the separate outcomes more directly.

The secondary results are unadjusted. When several outcomes are examined, the chance of observing at least one apparently notable result by chance can increase. This general multiplicity concern makes isolated unadjusted p-values less persuasive than a result interpreted under a prespecified analysis plan. The registry record does not report such a plan or any multiplicity adjustment. The dimension and procedural-failure findings therefore warrant cautious interpretation, especially alongside the uncertain primary comparison and the missing posted radial pulse result.

Outcome denominators vary: the dimension measure has fewer observations than the primary outcome, and the pain outcome uses 48.0 participants in each arm. The reasons are not reported in the registry record. Differences in the available participants can affect precision and potentially the comparability of observed summaries if the missingness relates to outcomes or treatment assignment. The record does not describe missing-data handling, so no explanation for the denominator differences should be assumed.

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

• Change in Radial Artery Dimension Measured in mm^2.
• Number of Patients With Procedural Failure
• Patient Discomfort or Pain During Procedure (Visual Analog Scale 0-10)
• Radial Pulse at End of Procedure

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is binary: each participant either met the spasm definition or did not. For a binary outcome, an arm’s event proportion is the number of participants with the event relative to the number assessed for that outcome. The posted comparison uses a risk difference, with the study arm contrasted against the control arm. A negative risk difference means the observed event proportion is lower in the study arm; a positive value would mean it is higher. This absolute contrast expresses the difference in event proportions rather than a relative change.

The primary estimate is accompanied by an interval. In general, a confidence interval describes a range of values reasonably compatible with the observed data under the method used. It communicates uncertainty around an estimate, rather than identifying a guaranteed range for the true effect. For the primary outcome, the reported interval crosses zero. Since zero represents no risk difference, the interval allows no difference as well as contrasts in either direction. The registry record does not state the confidence level or the method used to construct the interval.

The unadjusted p-value for the primary comparison is 0.148. In general, a p-value describes how unusual data at least as incompatible with a specified null model would be if that model and the test assumptions held. It is not the probability that the null hypothesis is true, nor does it measure the size or importance of an effect. The registry’s planning assumptions mention a two-sided significance level of 0.05; that is a stated assumption for the planning illustration, not a reported prespecified threshold for the original trial. The record does not identify the test used for the primary comparison.

The radial artery dimension outcome is continuous and is reported as a mean change with a standard deviation for each arm. A mean summarizes the average change; a standard deviation describes the spread of individual measurements around the arm mean. The posted mean difference is 2.7 mm^2, with an interval from 2.108 to 3.292 and an unadjusted p-value of <0.001. These summary statistics describe the observed change and its uncertainty. The registry record does not report the measurement instrument, details of measurement timing beyond the stated timeframe, or the statistical test used.

Pain or discomfort is also reported as a continuous outcome, using a visual analog scale from 0 to 10. The arm means are 0.792 for the study arm and 0.875 for the control arm, with standard deviations of 2.031 and 1.965. The reported mean difference is -0.083 and the unadjusted p-value is 0.839. The interval crosses zero, so this summary does not precisely distinguish a difference from no difference. In general, a standard deviation helps describe variability in observed scores; it is not the uncertainty interval for the mean difference.

Procedural failure is another binary outcome. The posted counts are 0.0 in the study arm and 4.0 in the control arm. The unadjusted p-value is 0.05. With an event absent from one arm’s observed count, the comparison can be sensitive to the method used for inference. The registry record does not report the specific test, any continuity correction, or a model-based analysis. The p-value should therefore be read as the registry’s unadjusted summary, not as a complete account of the analysis.

Randomization is intended to make assigned groups comparable on average, while double masking is intended to limit influences on treatment delivery and outcome assessment. These design labels do not answer questions about implementation or analysis. The registry record does not describe sequence generation, concealment, adherence, crossovers, exclusions, or the population used for each analysis. Nor does it list reported adjusted analyses. The available comparisons are therefore best treated as unadjusted arm-level summaries.

Over-dispersion is a general concern when binary event data vary more than a simple model assumes. If a model treats participants’ outcomes as more independent or homogeneous than they are, its uncertainty estimates may be too small. The posted registry summaries do not identify an over-dispersion model, and the record does not supply enough analysis detail to assess whether this issue was evaluated. This is a general statistical consideration, not a claim that over-dispersion occurred in this trial.

11. Confidence Intervals and Precision

The primary event counts are 8.0 of 48.0 in the study arm and 15.0 of 52.0 in the control arm. The reported risk difference is negative, but its interval extends across zero: it ranges from -0.284 to 0.040. That span means the data do not rule out no difference, and they also allow both a lower and a higher event proportion in the study arm. The unadjusted p-value of 0.148 is consistent with substantial uncertainty about the direction and size of the primary contrast. The registry record does not state the interval’s confidence level.

Precision is not the same as the observed direction of an estimate. The event counts point toward a lower observed proportion in the study arm, but an estimate can have that direction while remaining uncertain. The interval is a useful companion to the point estimate because it conveys the range of values compatible with the data under the method used. It should not be interpreted as a probability distribution over possible effects or as a guarantee that the true effect lies within its limits.

Precision also differs across outcomes. The dimension outcome has a reported interval from 2.108 to 3.292, whereas the pain comparison’s interval spans -0.882 to 0.716. The procedural-failure interval ranges from -0.149 to -0.004. These intervals describe different outcomes and scales; their widths should not be compared as if they measured the same quantity. The registry record does not specify the interval construction methods, which limits further assessment of precision.

For the primary endpoint, the number assessed in each arm is modest relative to the range of possible event proportions, and the interval remains broad enough to include contrasts in either direction. This is a statement about the uncertainty in the posted estimate, not a conclusion about the underlying clinical effect. The registry record does not report an original sample-size justification or any interim analysis plan that could add context to the precision of the final result.

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 figures are participants per arm for the binary and continuous outcomes in this trial; they are not total event counts. The record’s general planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each illustration uses a stated fraction of the observed effect as the effect to detect. The original trial’s own sample-size assumptions and justification are not reported in the registry record.

The 80% power column gives the planned number of participants per arm that the calculation estimates would be needed to have an 80% chance of detecting the selected effect under those planning assumptions, if that effect were the true effect and the model assumptions held. The 90% power column describes the corresponding planning target for a 90% chance. These are design calculations, not guarantees of detection and not evidence that the trial achieved a particular probability of finding a result.

The rows use 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect. A smaller effect is harder to distinguish from random variation, so the illustrations require more participants per arm as the assumed effect becomes smaller. For the primary binary outcome, the figures are 185 and 247 participants per arm for 100% of the observed effect, 345 and 461 for 75%, and 810 and 1,083 for 50%, for the 80% and 90% targets respectively. They are planning illustrations based on the observed contrast, not a reconstruction of the trial’s original design decision.

This is not observed power. Observed power is sometimes calculated using the estimated effect after a study, but it does not provide a useful substitute for interpreting the estimate and its interval. These planning figures instead show how sample-size requirements change under explicit assumptions about the effect to detect. They should not be read as evidence that an outcome was adequately or inadequately powered under the trial’s original plan, which is not reported in the registry record.

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 = 0.288; treatment proportion p₁ = 0.167; average p̄ = 0.228.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.5929 = 1.1621.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5866 = 0.4937.
4. n = (1.1621 + 0.4937)² / (-0.1218)² = 184.8, rounded up to 185 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 <- 0.288461538461538                          # control proportion
p1 <- 0.166666666666667                          # 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(2832115)
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 = 185 (80% power), 247 (90% power)
 75% of observed effect: n per arm = 345 (80% power), 461 (90% power)
 50% of observed effect: n per arm = 810 (80% power), 1,083 (90% power)
power.prop.test: 184.8 
Simulated power at n = 185 per arm: 0.801 (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 lists one primary endpoint and four secondary outcomes. It does not report how the primary outcome was designated in a statistical analysis plan, whether secondary outcomes were ranked or considered exploratory, or whether any correction for multiple testing was planned or applied. The posted secondary p-values are unadjusted. In general, testing several outcomes creates more opportunities for an apparently unusual result to occur by chance, so secondary findings are most informative when interpreted in the context of prespecification and multiplicity procedures. Those details are not reported in the registry record.

The registry’s analysis listings contain no reported analyses. The available arm summaries and unadjusted comparisons do not establish whether analyses followed an intention-to-treat, per-protocol, or other population definition. The record does not report exclusions after randomization, crossover handling, adherence, or treatment discontinuation. These omissions limit assessment of whether the posted comparisons preserve the randomized groups throughout analysis.

The outcome denominators are not the same for every measure. The primary endpoint and procedural failure use 48.0 participants in the study arm and 52.0 in the control arm. The dimension outcome uses 42.0 and 45.0, and pain uses 48.0 in each arm. The radial pulse outcome is listed but its results are not reported in the registry record. Reasons for the different denominators, the amount and pattern of missing data, and any imputation or sensitivity analyses are not reported in the registry record.

Missingness matters because an analysis restricted to participants with observed outcomes can be biased if inclusion depends on treatment assignment or on the outcome itself. This is a general methodological concern; the registry information does not establish that such bias occurred. It also does not provide participant flow by outcome or enough detail to judge whether the missing observations were plausibly unrelated to the comparisons.

The registry record does not report an interim analysis plan, stopping rules, or a prespecified statistical model. The planning illustration’s significance level does not establish the trial’s original analysis threshold. Without those protocol details, the posted p-values should be treated as descriptive unadjusted results rather than as a complete record of the trial’s inferential strategy.

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.

Most frequent non-serious adverse event terms

The posted serious adverse event counts are 0 in the study arm among 48 participants at risk and 0 in the control arm among 52 participants at risk. Deaths are recorded as 0 in each arm. These figures describe the events recorded in the registry; they do not establish that no adverse events of any kind occurred. The registry also lists 5 other adverse events in each arm among the respective participants at risk.

No serious adverse event terms are listed. The registry record does not provide event descriptions, severity grading details, timing, attribution to treatment, or information about how events were collected. It is therefore not possible to infer from these counts whether an event was related to the study preparation or to the procedure. With no serious events recorded in either arm, the posted figures also do not estimate a comparative difference in serious-event risk with useful precision.

Safety counts should be read alongside the registry’s definitions and follow-up procedures, which are not reported in the registry record. They are descriptive counts for the recorded trial participants, not evidence that serious or other harms are impossible. The observed counts should not be generalized beyond the information and follow-up represented in the registry.

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

The posted primary results show fewer participants meeting the radial artery spasm definition in the topical lidocaine-plus-nitroglycerine arm than in the lidocaine-plus-placebo arm. The reported risk-difference interval includes zero and extends in both directions, while the unadjusted p-value is 0.148. The evidence therefore does not precisely establish the direction or size of a difference in the primary endpoint. The observed direction is a description of these trial data, not proof of a causal effect.

The secondary results give additional but distinct information. The artery dimension measure and procedural-failure count have observed contrasts favoring the study arm, while the pain means are close and the radial pulse result is not reported in the registry record. Because the outcomes are different and the secondary p-values are unadjusted, these findings should not be combined into a single claim of benefit or treated as substitutes for the primary result. The registry record does not report a multiplicity plan that would support stronger conclusions from isolated secondary findings.

The results also do not establish the broader objectives named in the study description. Post-procedure radial artery patency is mentioned as an objective, but the posted secondary outcome is radial pulse at the end of the procedure, for which results are not reported in the registry record. The record does not report a distinct patency measurement or a result for it. Likewise, the primary composite does not identify which of its component signs or procedural events accounts for the observed counts.

Interpretation is constrained by the absence of the original sample-size justification, the statistical analysis plan, and information about missing outcomes and analysis populations. Outcome denominators vary, and the reasons are not reported. These limitations do not negate the posted summaries, but they limit how confidently the results can be extended beyond those summaries. The findings describe this completed, single-center randomized comparison; they do not establish results for other settings, patient groups, or procedural practices.

In general, statistical uncertainty and clinical importance are separate questions. A point estimate and its interval describe the range and precision of an observed contrast, while judgments about clinical importance require context that is not fully reported in the registry record. No treatment recommendation follows from the registry summaries alone.

17. Why This Trial Matters Statistically

This trial illustrates why an estimate should be read together with its uncertainty. The primary event counts point toward fewer observed spasm events in the study arm, yet the interval includes no difference and the unadjusted p-value does not provide strong evidence against a no-difference model. Reporting only the direction of the point estimate would lose the central statistical message: the primary comparison remains uncertain.

The endpoint also demonstrates a common trade-off in clinical measurement. A composite can capture several ways a procedural problem may present, but a total event count may hide which component contributes to the result. Here the spasm definition combines symptoms, technical difficulty, and additional medication. Without component-specific counts, the overall contrast cannot be attributed to any one of those features.

The secondary outcomes show why a coherent clinical narrative should not be built from whichever unadjusted result appears most notable. The measures concern different constructs, their denominators vary, and the registry does not report a multiplicity strategy. The dimension and procedural-failure summaries may be relevant, but they do not remove uncertainty in the primary endpoint or make unreported outcomes available.

The planning illustrations highlight a further statistical distinction: sample-size calculations depend on the effect assumed for planning. Smaller assumed effects require larger planned groups under the stated assumptions. These illustrations are based on observed effects and do not reveal the original design rationale or the probability that this trial would detect a true effect. Separating planning calculations from observed results prevents a common misreading of power.

Finally, the record’s limited reporting of missing data, analysis populations, and prespecified methods shows why transparent reporting matters. Such details help readers judge whether uncertainty estimates and p-values reflect the intended analysis and how far the conclusions can reasonably extend.

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 registry record does not report the protocol’s sample-size justification, prespecified analysis plan, randomization sequence method, allocation concealment, or masking implementation. These details would help assess how the design was carried out and how the posted comparisons relate to the planned analysis. No interim analysis plan or stopping rules are reported.

Reasons for differing outcome denominators are not reported. The dimension measure includes 42.0 participants in the study arm and 45.0 in the control arm, while the primary endpoint uses 48.0 and 52.0. The pain analysis uses 48.0 in each arm. The record does not describe missing-data handling, participant flow by outcome, exclusions, crossover, adherence, or analysis populations. These omissions limit assessment of possible selection effects and the extent to which the randomized groups were retained in each comparison.

Results for radial pulse at the end of the procedure are not reported in the registry record, despite that outcome being listed among the secondary measures. The primary composite is reported as an overall event count without component-specific results. The registry also does not report the method used to calculate the comparison intervals or tests, the confidence level for the intervals, or adjusted analyses. These gaps constrain evaluation of the statistical methods and the connection between the composite endpoint and its individual components.

The study is described as single-center, which limits how directly the results may apply to settings with different operators, patients, or procedural practices. The registry does not report details about participant characteristics that would help assess the population represented. Safety reporting is also limited: serious-event counts, other-event counts, and deaths are listed, but event descriptions, attribution, collection procedures, and follow-up details are not reported.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Topical Nitroglycerine Treatment for Radial Artery Spasm Prevention — NCT02832115.
• Registry record last updated 2020-10-27; status last verified 2020-10.
• Results first posted 2020-10-27.
• 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

The registry describes a completed, randomized, double-blind, parallel-group, placebo-controlled Phase 4 study at a single center, with enrollment of 100. It compared topical lidocaine plus nitroglycerine against topical lidocaine plus placebo before transradial coronary procedures. The primary outcome was a composite-defined incidence of radial artery spasm during the procedure.

The primary event counts were 8.0 of 48.0 in the study arm and 15.0 of 52.0 in the control arm. The posted risk-difference interval includes zero, and the unadjusted p-value is 0.148, leaving the primary comparison uncertain. Secondary results cover artery dimension, procedural failure, pain or discomfort, and radial pulse; the radial pulse result is not reported in the registry record. The original sample-size rationale, analysis plan, and reasons for outcome denominator differences are also not reported in the registry record.