This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Evaluate the Safety and Efficacy of OAS in Treating Severely Calcified Coronary Lesions (NCT01092416), a na na study. The primary outcome is Primary Safety Endpoint: 30-Day Freedom From Major Adverse Cardiac Events (MACE).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01092416 |
| Phase | NA |
| Condition | Coronary Artery Disease |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 443 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Abbott Medical Devices |
| Results posted | Yes |
2. Clinical Question
Population
Adults with de novo, severely calcified coronary lesions and coronary artery disease. The registry record lists enrollment of 443 participants.
Intervention
The Diamondback 360 Orbital Atherectomy System. The study summary says participants were also treated with an adjunctive stent.
Comparator
There was no comparison group: this was a single-arm study, and all participants received the intervention.
Primary question
What was the estimated probability of remaining free from major adverse cardiac events through 30 days after the procedure?
The registry describes a prospective, multicenter study evaluating the safety and performance of orbital atherectomy in severely calcified coronary lesions. Its primary safety endpoint was freedom from major adverse cardiac events at 30 days, assessed using a Kaplan-Meier analysis. The primary efficacy endpoint was procedural success, but its definition and result are not reported in the registry record.
Because the study had no control arm, it addresses outcomes among participants treated with the system, rather than estimating a treatment effect against another procedure or usual care. A single-arm outcome can describe what happened during follow-up in the enrolled group. By itself, it cannot show how those outcomes compare with what would have happened under a different treatment.
The registry record reports enrollment of 443, while its study summary says it planned to enroll up to 429 subjects at up to 50 U.S. study sites. The reason for the difference is not reported in the registry record. The record lists the condition as coronary artery disease and describes the target lesions as de novo and severely calcified.
3. Trial Design
ORBIT II is identified as a prospective, single-arm, multicenter study of the Diamondback 360 Orbital Atherectomy System. Its official title describes a pivotal trial evaluating the system in de novo, severely calcified coronary lesions. The registry lists the study as completed, with an enrollment of 443. The study summary describes a plan to enroll up to 429 subjects at up to 50 U.S. study sites; the relationship between that planned maximum and the listed enrollment is not reported in the registry record.
All participants were to receive the orbital atherectomy system and an adjunctive stent, according to the study summary. The record lists no allocation and no masking. The phase is recorded as not applicable. With one treatment group and no randomized comparator, the design does not provide a like-for-like control group for estimating comparative effects.
The primary safety endpoint was 30-day freedom from major adverse cardiac events. The primary efficacy endpoint was procedural success. Secondary outcomes listed in the record were angiographic success, severe angiographic complications, and 12-month freedom from major adverse cardiac events. The definitions and numerical results for the efficacy and secondary outcomes are not reported in the registry record.
The summary specifies clinic follow-up at 30 days, with annual phone or clinical follow-up at each anniversary until study closure. The primary completion date is listed as 2013-01, and the study start as 2010-05. More detail about enrollment criteria, site-level conduct, follow-up completeness, and the timing of the final study closure is not reported in the registry record.
The record lists Abbott Medical Devices as sponsor. It does not describe a randomized allocation procedure, blinding, or a concurrent comparison group. These design features matter when interpreting the observed safety and performance outcomes: the results can characterize this enrolled cohort, but the study design alone cannot separate treatment effects from other explanations for outcomes.
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.
Before assignment: A subject was considered enrolled when a signed informed consent was in place, all inclusion/no exclusion criteria were met, and the study guidewire had crossed the target lesion.
Enrollment
| Stage | ORBIT II Subjects |
|---|---|
| STARTED | 443 |
| COMPLETED | 440 |
| NOT COMPLETED | 3 |
Reasons for not completing this period:
| Reason | ORBIT II Subjects |
|---|---|
| Atherectomy device not inserted | 3 |
30-Day Follow-up
| Stage | ORBIT II Subjects |
|---|---|
| STARTED | 440 |
| COMPLETED | 430 |
| NOT COMPLETED | 10 |
Reasons for not completing this period:
| Reason | ORBIT II Subjects |
|---|---|
| Death | 2 |
| Missed 30-day follow-up | 3 |
| Data collected after close of 30D window | 5 |
12-Month Follow-up
| Stage | ORBIT II Subjects |
|---|---|
| STARTED | 438 |
| COMPLETED | 413 |
| NOT COMPLETED | 25 |
Reasons for not completing this period:
| Reason | ORBIT II Subjects |
|---|---|
| Death | 16 |
| Lost to Follow-up | 4 |
| Withdrawal by Subject | 2 |
| Missed 1-year follow-up | 1 |
| Data collected after close of 1Y window | 2 |
Analysis population for the primary outcome, as defined in the registry: A Kaplan-Meier analysis was performed to determine the percent probability that a study participant is free from major adverse cardiac events at 30 days.
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.
| Characteristic | Unit | ORBIT II Subjects |
|---|---|---|
| Participants analysed | 443 | |
| Age, Continuous | years | 71.4 (37.4 to 92.2) |
| Sex: Female, Male: Female | Participants | 157 |
| Sex: Female, Male: Male | Participants | 286 |
| Race/Ethnicity, Customized: Caucasian | participants | 390 |
| Race/Ethnicity, Customized: Black or African American | participants | 25 |
| Race/Ethnicity, Customized: Asian | participants | 9 |
| Race/Ethnicity, Customized: Hispanic or Latino | participants | 15 |
| Race/Ethnicity, Customized: Native American | participants | 1 |
| Race/Ethnicity, Customized: Other | participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Primary Safety Endpoint: 30-Day Freedom From Major Adverse Cardiac Events (MACE), measured over 30 days.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | Percent probability of Freedom from MACE |
| Endpoint classification | not reduced to a single comparison |
The primary safety endpoint is the probability of being free from major adverse cardiac events (MACE) at 30 days after the procedure. The registry says this probability was estimated using Kaplan-Meier analysis. MACE is a composite of cardiac death, myocardial infarction, and target-vessel revascularization after the index procedure. Myocardial infarction is defined in the record by a CK-MB level greater than 3 times the upper limit of the laboratory normal value, with or without a new pathologic Q wave. Target-vessel revascularization includes revascularization of the target vessel, including the target lesion, after completion of the index procedure.
A composite endpoint groups several clinically distinct events into one outcome. In general, this can capture more kinds of adverse outcomes than any one component alone, but the components may differ in seriousness and frequency. A composite result therefore does not, by itself, reveal which component contributed most. Component-specific primary-endpoint results are not reported in the registry record.
Kaplan-Meier analysis is generally used to estimate the chance of remaining free of an event over time when participants may have different lengths of follow-up or may leave observation before the endpoint occurs. It uses the timing of events and censoring rather than treating every participant as if follow-up were identical. The record identifies the method and timeframe, but does not report the estimated 30-day probability, its 95% confidence interval, the number of endpoint events, or the censoring details. The endpoint definition therefore explains what the analysis was intended to measure, but does not establish the observed result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clear primary safety question: the estimated probability of remaining free from MACE at 30 days. However, it does not report the primary endpoint estimate or its 95% confidence interval. It also does not report the number of primary endpoint events or component-specific results. As a result, the primary safety outcome cannot be quantified from the information in the record, and its precision cannot be assessed.
The record says the primary endpoint was analyzed with Kaplan-Meier methods. In general, a point estimate describes the estimated event-free probability at the specified time, while a confidence interval conveys statistical uncertainty around that estimate. A narrow interval would indicate greater precision than a wide interval, but neither the estimate nor interval is available in the registry record. No conclusion about the size or precision of the 30-day safety outcome can therefore be drawn from the endpoint description alone.
The study was single-arm: participants received the orbital atherectomy system, and the summary also says they received an adjunctive stent. There was no concurrent control group. Thus, even if an outcome estimate were available, it would describe the enrolled group’s observed experience rather than provide a randomized comparison with another treatment. The design does not isolate the contribution of the atherectomy system from the procedure as a whole or from other influences on outcomes.
The registry lists 443 enrolled participants. Its study summary says the plan was to enroll up to 429 subjects. The reason for the difference is not reported in the registry record, and the enrollment figure should not be assumed to equal the analysis population for each outcome. The number included in the primary endpoint analysis, the handling of participants with incomplete follow-up, and the analysis population definition are not reported in the registry record.
The adverse-event record lists 30-day and one-year groups, with serious and other adverse-event counts. Those figures are not substitutes for the primary endpoint result: the listed adverse-event categories are not described as the primary MACE analysis, and the registry does not provide enough detail to reconcile them with that endpoint. The record also lists serious adverse-event terms with percentages, but does not provide the corresponding term-specific counts or denominators in the details available.
Overall, the record describes the design, endpoint, and some adverse-event reporting, but lacks the numerical primary outcome needed to assess the stated safety question. It also lacks a comparator, so the study cannot establish a treatment difference against another approach. These are limits on what the posted information supports, not evidence for or against the device’s performance.
9. Statistical Methods Explained
The registry names Kaplan-Meier analysis for the primary safety endpoint. This is a time-to-event method: it estimates the probability of remaining free of an event through a specified time while accounting for participants whose observation ends before that time. Such participants may be censored, meaning that their event status is known only up to their last observed follow-up. Kaplan-Meier estimation relies on assumptions about censoring and follow-up; the registry record does not describe how censoring was handled or report the number censored.
The primary endpoint is a freedom-from-event probability at 30 days, not a comparison between two treatment groups. The record describes the event as a composite of cardiac death, myocardial infarction, and target-vessel revascularization after the index procedure. In general, a time-to-event composite treats the first qualifying event as the endpoint event. The registry’s description does not spell out event adjudication procedures, how simultaneous or recurrent components were counted, or the analysis rules for individual components. Those details are not reported in the registry record.
A 95% confidence interval is intended to express uncertainty around an estimated quantity under the statistical method used. It is not a guarantee that the true value lies within the interval. The registry identifies a 95% confidence interval as the dispersion measure for the primary endpoint, but the estimate and interval are not reported in the registry record. Without them, neither the estimated event-free probability nor the width of its uncertainty interval can be evaluated.
What does a single-arm design allow?
In a single-arm study, outcomes are measured in one group receiving the intervention. The design can describe that group’s observed outcomes over follow-up. It cannot directly estimate a between-group treatment contrast because no concurrent control group is included. In ORBIT II, the record lists no allocation and no masking, and the study model is single group. It does not report a randomized comparison or an external control analysis. Consequently, a causal comparison with another treatment is not part of the reported design.
The record’s description says all participants would receive the orbital atherectomy system and an adjunctive stent. This means an observed outcome belongs to the treatment and procedural context recorded for the cohort. The registry does not describe a method that would separate the effects of each component. General statistical interpretation therefore distinguishes a cohort outcome from a treatment effect: a cohort outcome is descriptive, while a treatment effect requires a credible comparison and assumptions about how groups differ.
How should composite endpoints be understood?
A composite combines multiple event types into a single endpoint. Here, the registry defines MACE using cardiac death, myocardial infarction, and target-vessel revascularization. This approach can summarize several forms of adverse outcome in one measure. However, a composite probability does not tell readers how often each component occurred, whether one component dominated the overall result, or whether components had similar clinical importance. Component-level estimates are not reported in the registry record.
The myocardial infarction definition uses a CK-MB threshold greater than 3 times the upper limit of the laboratory normal value, with or without a new pathologic Q wave. The target-vessel revascularization definition includes revascularization at the target vessel, including the target lesion, after the index procedure. The record does not report laboratory sampling schedules, event-adjudication methods, or additional operational rules for applying these definitions.
What can adverse-event counts tell readers?
Adverse-event counts describe reported events or participants affected within the registry’s categories. They are not automatically equivalent to a time-to-event endpoint, and they should not be substituted for the Kaplan-Meier MACE estimate. The adverse-event record lists separate groups for 30-day and one-year results, with counts for serious and other events. It does not explain the relationship between those categories and the primary endpoint, or whether a participant could contribute to more than one listed event. The counts should therefore be read as the record’s adverse-event reporting, not as a reconstructed MACE result.
The record lists several serious adverse-event terms with percentages. A percentage without a stated denominator and a clear account of whether it refers to participants or events has limited interpretability. The listed term percentages should not be added together or treated as mutually exclusive categories unless the registry establishes that structure; it does not. Death counts are not reported in the adverse-event group details.
What is missing about the statistical plan?
The registry record lists zero analyses and does not provide numerical results for the primary endpoint. It does not report the statistical analysis plan, sample-size justification, interim analyses, multiplicity adjustment, missing-data methods, or a defined analysis population. The primary endpoint description does identify Kaplan-Meier analysis and a 95% confidence interval, but that is not enough to reconstruct the full analysis procedure.
The study summary gives a planned enrollment ceiling of up to 429 subjects, whereas the registry lists enrollment of 443. The reason for that difference is not reported in the registry record. The sample-size justification and any assumptions used in planning are also not reported in the registry record. Planning illustrations based on an observed effect are not observed power and do not replace the original design justification; the observed effect and the trial’s own planning rationale are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary safety endpoint, a primary efficacy endpoint, and secondary outcomes, but does not report how statistical testing across these outcomes was handled. No multiplicity adjustment or testing hierarchy is reported in the registry record. When several outcomes are tested, general statistical practice recognizes that the chance of at least one apparently notable result can increase unless the analysis plan accounts for multiple testing. Whether that issue was addressed for ORBIT II is not reported in the registry record.
The record does not report interim analyses, stopping rules, or whether any outcome definitions or analyses changed during the study. These details should not be inferred from the study’s completed status or from the listing of endpoints.
Analysis populations and missing-data procedures are also not reported in the registry record. The record does not state how many participants contributed to the primary endpoint analysis, how incomplete follow-up was handled, or how participants with missing endpoint information were treated. Kaplan-Meier methods can account for differing follow-up through censoring, but the censoring pattern and its handling are not described. The listed enrollment of 443 should therefore not be taken as the denominator for every endpoint analysis.
The registry summary describes planned enrollment of up to 429 subjects, while the enrollment field lists 443. The reason for this discrepancy is not reported in the registry record. Neither figure establishes the number of participants analyzed for a given outcome. Definitions of the efficacy endpoint and secondary outcomes, endpoint adjudication procedures, and the extent of missing outcome data are not reported in the registry record. These omissions limit assessment of how completely the reported outcomes reflect the enrolled cohort.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| ORBIT II Subjects - 30 Day Results | 109 | 443 | 24.6% |
| ORBIT II Subjects - 1 Year Results | 70 | 438 | 16.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| ORBIT II Subjects - 30 Day Results | 34 of 443 |
| ORBIT II Subjects - 1 Year Results | 0 of 438 |
Most frequent serious adverse event terms
| Event term | Organ system | ORBIT II Subjects - 30 Day Results | ORBIT II Subjects - 1 Year Results |
|---|---|---|---|
| Acute MI, non Q-wave | Cardiac disorders | 39 of 443 | 5 of 438 |
| Angina Pectoris | Cardiac disorders | 4 of 443 | 23 of 438 |
| Coronary vessel dissection present | Surgical and medical procedures | 23 of 443 | 0 of 438 |
| Coronary artery restenosis | Cardiac disorders | 0 of 443 | 20 of 438 |
| Cardiac death | Cardiac disorders | 1 of 443 | 12 of 438 |
| Atrial fibrillation | Cardiac disorders | 2 of 443 | 9 of 438 |
| Peripheral artery/vascular disease | Vascular disorders | 2 of 443 | 9 of 438 |
| Anemia | Blood and lymphatic system disorders | 0 of 443 | 9 of 438 |
| COPD | Respiratory, thoracic and mediastinal disorders | 1 of 443 | 7 of 438 |
| Pneumonia | Respiratory, thoracic and mediastinal disorders | 2 of 443 | 6 of 438 |
Most frequent non-serious adverse event terms
| Event term | Organ system | ORBIT II Subjects - 30 Day Results | ORBIT II Subjects - 1 Year Results |
|---|---|---|---|
| Angiographic Complications | Surgical and medical procedures | 34 of 443 | 0 of 438 |
Serious events with the highest arm-level rate: acute mi, non q-wave (8.8%), angina pectoris (5.3%), coronary vessel dissection present (5.2%), coronary artery restenosis (4.6%), cardiac death (2.7%).
The adverse-event record lists a 30-day group with 443 at risk, 109 affected by serious events, and 34 affected by other events. Its one-year group lists 438 at risk, 70 affected by serious events, and zero affected by other events. These are adverse-event group figures, not the numerical result for the primary 30-day MACE endpoint. The record does not explain whether the affected counts refer to participants with at least one event, how recurrent events were counted, or how the categories relate to MACE.
The listed serious-event terms and percentages are acute MI, non Q-wave at 8.8%, angina pectoris at 5.3%, coronary vessel dissection present at 5.2%, coronary artery restenosis at 4.6%, cardiac death at 2.7%, and atrial fibrillation at 2.1%. The registry entries do not give corresponding term-specific counts or denominators. These percentages should therefore be read as the registry’s listed values, not as a basis for reconstructing totals or comparing risks.
The death field is not reported in the registry record. The record also does not provide enough detail to establish whether the serious-event terms overlap within participants or whether event ascertainment differed across follow-up periods. The adverse-event figures describe reported safety information, but do not establish a comparative risk because the study had no control group.
12. What the Result Does, and Does Not, Mean
ORBIT II documents a prospective, single-arm evaluation of the Diamondback 360 Orbital Atherectomy System in adults with de novo, severely calcified coronary lesions. The registry specifies a primary safety endpoint based on 30-day freedom from MACE and identifies Kaplan-Meier analysis with a 95% confidence interval. It also lists procedural success as the primary efficacy endpoint and names several secondary outcomes.
The main limitation for interpreting the safety question is that the primary endpoint estimate and confidence interval are not reported in the registry record. The event count, component-specific results, and analysis population are also not reported. The endpoint definition and method describe what was intended to be measured, but they do not reveal the observed probability or its precision.
The single-arm design means the record can describe outcomes among participants who received the intervention and adjunctive stent, as described in the study summary. It cannot establish how those outcomes compare with a different treatment or with no atherectomy. Without a control group, differences attributable to treatment cannot be separated from other influences by a randomized comparison.
The adverse-event listing adds some information about events recorded at 30 days and one year, including serious-event counts and selected serious-event terms. These data do not replace the primary MACE analysis, and the registry does not report sufficient detail to connect them directly to that endpoint. They also do not provide a comparative estimate of safety.
Accordingly, the registry record supports a description of the study’s intent, design, endpoint definitions, and selected adverse-event reporting. It does not support a numerical conclusion about the primary safety outcome, the procedural success outcome, or comparative effectiveness. Those limits reflect the information and design recorded, rather than a conclusion about whether the system did or did not achieve a clinical benefit.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the distinction between an endpoint plan and an analyzable result. The record defines a time-specific, composite safety endpoint and names Kaplan-Meier analysis, but does not report the endpoint estimate or its confidence interval. A method label alone does not let readers judge the magnitude or precision of an outcome.
Its single-arm structure also illustrates why descriptive outcomes and comparative effects are different quantities. A cohort can be followed and its event experience described, but a treatment contrast requires a comparator. ORBIT II’s design has no concurrent control group, so it does not offer a randomized estimate of how outcomes differ under another approach.
The endpoint combines cardiac death, myocardial infarction, and target-vessel revascularization. That can create a broad summary outcome, while also making component-level reporting important for interpretation. The registry’s endpoint definition is available, but component-specific primary results are not reported in the registry record. This leaves unanswered how the components contributed to the overall safety measure.
The record also highlights the importance of transparent analysis details. The primary analysis population, missing-data approach, censoring information, multiplicity procedures, and sample-size justification are not reported in the registry record. The enrollment listing of 443 and the summary’s planned ceiling of up to 429 further illustrate why planned and recorded enrollment should be distinguished, while the reason for the difference remains unknown.
For clinical researchers and biostatisticians, the key lesson is that statistical interpretation depends on more than the endpoint name: the estimate, uncertainty, analysis population, follow-up, and design all shape what can be concluded. In this record, the design and intended methods are described more fully than the numerical primary result.
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.
The most important trial-specific limitation in the registry record is the absence of numerical results for the primary safety endpoint. Although the record identifies a Kaplan-Meier estimate of 30-day freedom from MACE and a 95% confidence interval, neither is reported. The primary efficacy endpoint of procedural success is named, but its definition and result are not reported in the registry record.
The study is single-arm and has no concurrent comparator. This limits interpretation to outcomes observed in the treated cohort and prevents a randomized treatment comparison. The study summary also says participants received an adjunctive stent, so the record does not describe a design that separates the contribution of atherectomy from the overall procedural treatment.
Some study conduct details are missing. The registry record does not report the primary analysis population, endpoint event count, censoring details, missing-data handling, adjudication procedures, or multiplicity approach. Definitions and numerical results for the listed secondary outcomes are also not reported. These gaps limit evaluation of endpoint completeness, analysis precision, and consistency across outcomes.
The record lists enrollment of 443, while the summary describes a plan to enroll up to 429 subjects at up to 50 U.S. sites. The reason for the difference is not reported in the registry record. It also does not report the sample-size justification or clarify the number analyzed for each outcome.
Adverse-event counts and selected serious-event percentages are listed, but their denominators and relationship to the primary endpoint are not fully described. Death counts are not reported in the registry record. These reporting limitations mean the adverse-event information cannot be treated as a substitute for the missing primary endpoint estimate.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Evaluate the Safety and Efficacy of OAS in Treating Severely Calcified Coronary Lesions — NCT01092416.
- Registry record last updated 2023-07-18; status last verified 2023-07.
- Results first posted 2016-01-06.
- 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.
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18. Record Summary
ORBIT II (NCT01092416) is a completed, prospective, single-arm, multicenter study sponsored by Abbott Medical Devices. It evaluated the Diamondback 360 Orbital Atherectomy System in de novo, severely calcified coronary lesions. The registry lists 443 enrolled participants; the study summary says it planned to enroll up to 429 subjects at up to 50 U.S. study sites.
The primary safety endpoint was 30-day freedom from MACE, defined using cardiac death, myocardial infarction, and target-vessel revascularization. The record says Kaplan-Meier analysis was used and identifies a 95% confidence interval, but the estimate and interval are not reported in the registry record. Procedural success was the primary efficacy endpoint; its definition and result are not reported.
The study summary says participants received the system and an adjunctive stent, with clinic follow-up at 30 days and annual phone or clinical follow-up until study closure. The registry lists secondary outcomes and selected adverse-event information. It does not report a control group, primary endpoint results, analysis-population details, or the statistical analysis plan.