Utility of Unfractionated Heparin in Transradial Cardiac Catheterization: A Systematic Review and Meta-analysis

Treatment Effects in Randomized and Nonrandomized Studies of Pharmacological Interventions: A Meta-Analysis

Importance

Randomized clinical trials (RCTs) are widely regarded as the methodological benchmark for assessing clinical efficacy and safety of health interventions. There is growing interest in using nonrandomized studies to assess efficacy and safety of new drugs.

Objective

To determine how treatment effects for the same drug compare when evaluated in nonrandomized vs randomized studies.

Data Sources

Meta-analyses published between 2009 and 2018 were identified in MEDLINE via PubMed and the Cochrane Database of Systematic Reviews. Data analysis was conducted from October 2019 to July 2024.

Study Selection

Meta-analyses of pharmacological interventions were eligible for inclusion if both randomized and nonrandomized studies contributed to a single meta-analytic estimate.

Data Extraction and Synthesis

For this meta-analysis using a meta-epidemiological framework, separate summary effect size estimates were calculated for nonrandomized and randomized studies within each meta-analysis using a random-effects model and then these estimates were compared. The reporting of this study followed the Guidelines for Reporting Meta-Epidemiological Methodology Research and relevant portions of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline.

Main Outcome and Measures

The primary outcome was discrepancies in treatment effects obtained from nonrandomized and randomized studies, as measured by the proportion of meta-analyses where the 2 study types disagreed about the direction or magnitude of effect, disagreed beyond chance about the effect size estimate, and the summary ratio of odds ratios (ROR) obtained from nonrandomized vs randomized studies combined across all meta-analyses.

Results

A total of 346 meta-analyses with 2746 studies were included. Statistical conclusions about drug benefits and harms were different for 130 of 346 meta-analyses (37.6%) when focusing solely on either nonrandomized or randomized studies. Disagreements were beyond chance for 54 meta-analyses (15.6%). Across all meta-analyses, there was no strong evidence of consistent differences in treatment effects obtained from nonrandomized vs randomized studies (summary ROR, 0.95; 95% credible interval [CrI], 0.89-1.02). Compared with experimental nonrandomized studies, randomized studies produced on average a 19% smaller treatment effect (ROR, 0.81; 95% CrI, 0.68-0.97). There was increased heterogeneity in effect size estimates obtained from nonrandomized compared with randomized studies.

Conclusions and Relevance

In this meta-analysis of treatment effects of pharmacological interventions obtained from randomized and nonrandomized studies, there was no overall difference in effect size estimates between study types on average, but nonrandomized studies both overestimated and underestimated treatment effects observed in randomized studies and introduced additional uncertainty. These findings suggest that relying on nonrandomized studies as substitutes for RCTs may introduce additional uncertainty about the therapeutic effects of new drugs.

Bivalirudin Versus Heparin Monotherapy in ST-Segment-Elevation Myocardial Infarction

BACKGROUND

Bivalirudin was not superior to unfractionated heparin in patients with myocardial infarction (MI) treated with percutaneous coronary intervention and no planned use of GPI (glycoprotein IIb/IIIa inhibitors) in contemporary clinical practice of radial access and potent P2Y₁₂-inhibitors in the VALIDATE-SWEDEHEART randomized clinical trial (Bivalirudin Versus Heparin in STEMI and NSTEMI Patients on Modern Antiplatelet Therapy-Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies Registry).

METHODS

In this prespecified separately powered subgroup analysis, we included patients with ST-segment-elevation MI undergoing primary percutaneous coronary intervention with the primary composite end point of all-cause death, MI, or major bleeding event within 180 days.

RESULTS

Among the 6006 patients enrolled in the trial, 3005 patients with ST-segment-elevation MI were randomized to receive bivalirudin or heparin. The mean age was 66.8 years. According to protocol recommendations, 87% were treated with potent oral P2Y₁₂-inhibitors before start of angiography and radial access was used in 90%. GPI was used in 51 (3.4%) and 74 (4.9%) of patients randomized to receive bivalirudin and heparin, respectively. The primary end point occurred in 12.5% (187 of 1501) and 13.0% (196 of 1504; hazard ratio [HR], 0.95 [95% CI, 0.78-1.17], P=0.64) with consistent results in all major subgroups. All-cause death occurred in 3.9% versus 3.9% (HR, 1.00 [0.70-1.45], P=0.98), MI in 1.7% versus 2.2% (HR, 0.76 [0.45-1.28], P=0.30), major bleeding in 8.3% versus 8.0% (HR, 1.04 [0.81-1.33], P=0.78), and definite stent thrombosis in 0.5% versus 1.3% (HR, 0.42 [0.18-0.96], P=0.04).

CONCLUSIONS

In patients with ST-segment-elevation MI undergoing primary percutaneous coronary intervention with radial access and receiving current recommended treatments with potent P2Y₁₂-inhibitors rate of the composite of all-cause death, MI, or major bleeding was not lower in those randomized to receive bivalirudin as compared with heparin. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02311231.

Transradial artery access for percutaneous cardiovascular procedures: state of the art and future directions

The transradial access (TRA) for cardiac catheterization and percutaneous coronary intervention (PCI) has been widely adopted in the last decades since its first description in the late 40s. The transradial approach has been associated with favorable outcomes as compared with transfemoral access (TFA) in several registries and randomized clinical trials, mainly due to the lower incidence of access-site bleedings, vascular complications and improved patient comfort. This review aimed to summarize the body of evidence supporting the use of TRA, to discuss clinical implications, possible technical limitations and future directions, such as the implementation of TRA as the primary access for complex procedures and structural interventions.

Predictors of patent and occlusive hemostasis after transradial coronary procedures

OBJECTIVES

To assess the independent predictors of patent and occlusive hemostasis (PH and OH, respectively) during radial hemostasis after coronary procedures.

BACKGROUND

Radial artery occlusion (RAO) is a thrombotic complication of transradial catheterization that can lead to permanent occlusion of the radial artery. Sheath-vessel diameter ratio, postprocedure compression time, occlusive hemostasis, inadequate, and excessive anticoagulation are all predictors of RAO.

METHODS

As a part of a previously published study investigating the relationship between residual anticoagulation and risk of RAO, 837 patients undergoing transradial diagnostic coronary angiography or percutaneous coronary interventions were enrolled. Cumulative heparin dose used during the procedure and ACT measured before sheath removal were recorded. PH with reverse Barbeau test was attempted in all patients (NCT02762344).

RESULTS

PH was less frequently obtained for increasing cumulative heparin dose and ACT values (p < .0001 and p = .0034, respectively). At logistic regression analysis both cumulative heparin dose and ACT values were independent predictors of OH (OR 1.017, 95% IC 1.011-1.023 p < .0001 and OR 1.004, 95% IC 1.001-1.006, p = .0004) while adjusted probability for RAO showed exponential relationship with both parameters.

CONCLUSIONS

The level of anticoagulation is strongly related to the incidence of RAO, and should be taken into account when choosing hemostasis protocol.

The Activated Clotting Time Paradox

Background:

Radial artery occlusion (RAO) is a thrombotic complication of transradial catheterization that can lead to permanent occlusion of the radial artery. Sheath-vessel diameter ratio, postprocedure compression time, occlusive hemostasis, and insufficient anticoagulation are all predictors of RAO. However, excessive anticoagulation can lead to longer time to achieve complete hemostasis and less patent hemostasis rate. This study was designed to assess the relationship among residual anticoagulation at the end of a percutaneous coronary procedure and the risk of RAO.

Methods:

Eight hundred thirty-seven patients undergoing transradial catheterization were enrolled. Activated clotting time (ACT) was measured before sheath removal. Patients were divided into 3 groups according to ACT values (ACT <150 s, ACT between 150 and 249 s, ACT >250 s), patent hemostasis with reverse Barbeau test was attempted in all patients, and compression device removed as soon as possible. Within 24 hours, patency of radial artery was checked by Doppler using reverse Barbeau technique.

Results:

Incidence of RAO was higher for the extreme ACT values. Patent hemostasis were less frequently obtained and time to hemostasis significantly longer for increasing ACT values ( P =0.004 for trend and <0.0001 for trend, respectively). At logistic regression analysis, ACT values <150 s were an independent predictor of RAO (odds ratio, 3.53; 95% IC, 1.677–7.43; P =0.001) while adjusted probability for RAO confirmed U-shaped relationship with ACT values.

Conclusions:

The level of anticoagulation is strongly related to incidence of RAO and should be measured objectively by ACT.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02762344.

Radial haemostasis is facilitated with a potassium ferrate haemostatic patch: the Statseal with TR Band assessment trial (STAT)

AIMS

Haemostasis is a limiting factor for discharge after uncomplicated transradial procedures. The purpose of this study was to determine whether a potassium ferrate haemostatic patch (PFHP) could serve as an adjunct to the air-bladder TR Band (TRB) to facilitate implementation of a rapid deflation protocol.

METHODS AND RESULTS

This was a prospective multicentre randomised controlled trial comparing radial haemostatic protocols. Deflation of the TRB was attempted at 40 minutes with PFHP and at 120 minutes without the PFHP. The primary outcome was time to full deflation of the TRB with haemostasis. At four US sites, 180 patients were enrolled after receiving a minimum of 5,000 units of unfractionated heparin or bivalirudin. Interventions comprised 30% of procedures. Successful TRB deflation occurred at 43±14 minutes with PFHP and 160±43 minutes without PFHP (p<0.001). Minor haematomas occurred in nine (10.3%) of the TRB patients and 16 (17.2%) of the PFHP patients (p=0.20). Radial artery occlusion occurred in 2% of patients in the PFHP group (p=NS). Outpatients randomised to PFHP were discharged 51±83.5 minutes earlier than control.

CONCLUSIONS

The PFHP haemostatic patch facilitated early deflation of the TRB with a non-significant increase in forearm haematomas. Use of the PFHP may improve patient throughput and allow earlier discharge following transradial procedures.

Bivalirudin versus heparin monotherapy in non-ST-segment elevation myocardial infarction

BACKGROUND

The optimal anti-coagulation strategy for patients with non-ST-elevation myocardial infarction treated with percutaneous coronary intervention is unclear in contemporary clinical practice of radial access and potent P2Y12-inhibitors. The aim of this study was to investigate whether bivalirudin was superior to heparin monotherapy in patients with non-ST-elevation myocardial infarction without routine glycoprotein IIb/IIIa inhibitor use.

METHODS

In a large pre-specified subgroup of the multicentre, prospective, randomised, registry-based, open-label clinical VALIDATE-SWEDEHEART trial we randomised patients with non-ST-elevation myocardial infarction undergoing percutaneous coronary intervention, treated with ticagrelor or prasugrel, to bivalirudin or heparin monotherapy with no planned use of glycoprotein IIb/IIIa inhibitors during percutaneous coronary intervention. The primary endpoint was the rate of a composite of all-cause death, myocardial infarction or major bleeding within 180 days.

RESULTS

A total of 3001 patients with non-ST-elevation myocardial infarction, were enrolled. The primary endpoint occurred in 12.1% (182 of 1503) and 12.5% (187 of 1498) of patients in the bivalirudin and heparin groups, respectively (hazard ratio of bivalirudin compared to heparin treatment 0.96, 95% confidence interval 0.78-1.18, p=0.69). The results were consistent in all major subgroups. All-cause death occurred in 2.0% versus 1.7% (hazard ratio 1.15, 0.68-1.94, p=0.61), myocardial infarction in 2.3% versus 2.5% (hazard ratio 0.91, 0.58-1.45, p=0.70), major bleeding in 8.9% versus 9.1% (hazard ratio 0.97, 0.77-1.24, p=0.82) and definite stent thrombosis in 0.3% versus 0.2% (hazard ratio 1.33, 0.30-5.93, p=0.82).

CONCLUSION

Bivalirudin as compared to heparin during percutaneous coronary intervention for non-ST-elevation myocardial infarction did not reduce the composite of all-cause death, myocardial infarction or major bleeding in non-ST-elevation myocardial infarction patients receiving current recommended treatments with modern P2Y12-inhibitors and predominantly radial access.