Vasodilators and Radial Artery Occlusion: A Concept to Reduce Radial Artery Occlusion?

Randomized Clinical Trial on Prevention of Radial Occlusion After Transradial Access Using Nitroglycerin: PATENS Trial

OBJECTIVES

The aim of this study was to evaluate whether administration of nitroglycerin at the beginning or end of a transradial approach (TRA) procedure would preserve radial patency.

BACKGROUND

The TRA is becoming the preferred vascular access route in coronary interventions. Radial artery occlusion (RAO) is the most frequent complication. Routine vasodilator treatment aims to reduce spasm and possibly prevent RAO.

METHODS

The authors designed a prospective, multicenter, randomized, double-blind, 2-by-2 factorial, placebo-controlled trial encompassing patients undergoing the TRA. Patients were randomized to either 500 μg nitroglycerin or placebo; each arm was also subrandomized to early (upon sheath insertion) or late (right before sheath removal) nitroglycerin administration to evaluate the superiority of nitroglycerin in the prevention of RAO with 24 hours on Doppler ultrasound.

RESULTS

A total of 2,040 patients were enrolled. RAO occurred in 49 patients (2.4%). Fifteen of these patients (30.6%) showed re-establishment of flow at 30 days. Nitroglycerin, compared with placebo, did not reduce the risk for RAO at either of the 2 time points (early, 2.5% vs 2.3% [P = 0.66]; late, 2.3% vs 2.5% [P = 0.66]). By multivariable analysis, the presence of spasm (OR: 3.53; 95% CI: 1.87-6.65; P < 0.001) and access achieved with more than 1 puncture attempt (OR: 2.58; 95% CI: 1.43-4.66; P = 0.002) were independent predictors of RAO.

CONCLUSIONS

The routine use of nitroglycerin was not associated with a reduction in the rate of RAO, regardless of the time of administration (at the beginning or end of the TRA procedure).

Distal Transradial Artery Access for Neuroangiography and Neurointerventions : Pitfalls and Exploring the Boundaries

Introduction

The distal transradial approach (dTRA) is progressively gaining more clinical use in the fields of cardiology and other vascular interventions, as it offers a number of advantages compared to conventional radial approach (TRA). These include lower rates of vascular occlusion which permits preservation of the proximal radial artery for future procedures in the event of a distal occlusion.

Aim

To share the experience in the use of dTRA for neurointerventions, showing its advantages, pitfalls as well as sharing our optimized puncture and hemostatic ultrarapid compression protocols to improve the use of this vascular access.

Methods

A retrospective analysis of our experience of diagnostic and interventional procedures performed via dTRA using an optimized protocol for puncture and postpuncture compression of the dTRA was performed.

The rate of complications (hematoma and arterial dissection at puncture site) femoral crossover, and assessment of postprocedural stenosis/occlusion with the ultrarapid compression protocol were also assessed.

Results

From March 2019 to July 2020 a total of 100 distal radial procedures were carried out and 53 diagnostic angiograms (53%) and 47 interventional procedures (47%) were included in the analysis. We achieved a 96% technical success, with a femoral crossover requirement in 3 cases (3%), and one conventional TRA crossover due to puncture failure.

Of the patients 3 presented puncture site hematomas (3%) with no intervention required, 61 patients (61%) underwent the ultrarapid hemostasis protocol in association with a hemostatic pad. Ultrasound follow-up was performed in 20 patients (20%) at 1–2 months with 1 case of occlusion (5%) and 2 of radial stenosis (10%). In all 3 cases proximal radial artery remained patent.

Conclusion

The dTRA is a safe and feasible access route for angiography and neurointerventions. Using vasodilators prepuncture, we attained a variable increase in the vascular diameter facilitating puncture and reducing the risk of occlusion and vascular spasm.

A rapid deflation protocol for postpuncture hemostasis does not significantly increase the hematoma rate.

Collateral Circulation Testing of the Hand- Is it Relevant Now? A Narrative Review

Testing for collateral circulation of the hand before any radial artery procedure has been a subject of many controversies. Neither the Allen's test (AT) nor the plethysmography based Barbeau test, adequately and reliably test for collateral circulation. With growing interest in radial approaches for vascular procedures, its common use for arterial monitoring and blood gas sampling, there has been a growing interest in the relevance of assessing collateral hand circulation. Multiple studies now refute the utility of collateral testing, yet it continues to be propagated as an essential triaging assessment tool by educators. Allen's, or modified Allen tests (MAT) are operator dependent and often subjected to observational bias. Barbeau test is more objective, however, it fails to show added benefit in assessing pre-procedural patency. Despite studies questioning the validity of collateral circulation assessment, these tests continue to preclude radial approach. There is no standardization for being considered an abnormal test across literature and the significance of an abnormal test translating into a clinical outcome has not been investigated in prior studies. This may be attributed to the robust vascular supply of the hand, connections at the digital circulation level and vessel recruitment in an event of occlusion. We reviewed this topic extensively and make an argument that non-invasive collateral testing should be abandoned as a triage tool for radial artery procedures such as arterial punctures, arterial monitoring, and transradial vascular procedures.

Can Children Be Considered for Transradial Interventions?: Prospective Study of Sonographic Radial Artery Diameters

BACKGROUND

Transradial intervention is increasingly replacing approaches, due to lower access complications, cost, and improved patient satisfaction. There are limited supporting data in the pediatric literature, largely due to concerns regarding arterial size. The objective of this study was to measure radial artery diameters in children across all age groups, to establish reference ranges for clinical use.

METHODS

This prospective study was carried out in children ≤18 years of age who underwent ultrasound for measuring radial artery diameters from November 2018 to November 2019. The cohort was divided into age groups: ≤2, 3 to 5, 6 to 8, 9 to 11, 12 to 14, 15 to 18 years, and into pre- and post-adolescent (≥12 years) groups.

RESULTS

One hundred thirty-four children (M:F=63:71) were included, with bilateral measurements resulting in 268 data points. Mean age was 8.9±5.8 years (range, 29 days to 18 years), mean weight 37.2±27.5 kg (range, 1.7-149.1 kg). Mean-corrected radial artery diameter was 1.86±0.44 mm. There was no difference in arterial diameters between males and females (1.90±0.50 versus 1.81±0.53 mm; P=0.73) or between right and left sides (1.87±0.46 versus 1.87±0.47, P=0.98). There was a strong correlation of diameter with age (R=0.75; P<0.00001) and weight (R=0.74; P<0.00001). There was linear increase in arterial growth rates in early childhood, followed by plateauing to adult sizes in adolescents. Inter-reader agreement was 0.95.

CONCLUSIONS

We provide a reference range for radial artery diameters across childhood ages, which can be used for decision-making. This could be the basis for designing a trial of transradial intervention in children, to establish clinical safety and efficacy.

Palmar Warming for Radial Artery Vasodilation to Facilitate Transradial Access: A Randomized Controlled Trial

PURPOSE

To investigate the efficacy of palmar warming to induce radial artery vasodilation.

MATERIALS AND METHODS

After informed consent was obtained, healthy volunteers (n = 45) were randomized 2:1 in palmar warming and control groups, respectively, for this prospective, randomized, single-blind clinical trial (NCT03620383). The palmar warming group was given a warm, commercially available, air-activated heat pack (Kobayashi Consumer Products LLC, Dalton, Georgia) to hold in the left hand for palmar warming. The control group was given a deactivated version of the same heat pack. Left radial artery cross-sectional area (CSA) measurements were obtained at baseline and in 5-minute intervals up to 20 minutes in both groups. Differences in the trends of changes in the radial artery CSA between palmar warming and control groups were examined with the age- and sex-adjusted repeated measure analysis of variance. Propensity score-matched treatment effect analysis was conducted to quantify the effect of heat on radial artery CSA.

RESULTS

The palmar warming group and the control group were significantly different in terms of subject sex (males/females: 7/23 and 10/5, respectively; P = .005) and baseline CSA (2.5±0.2 mm² vs 3.2±0.3 mm², respectively; P = .014). Radial artery CSA showed an increasing trend over time in the palmar warming group compared to a stable trend over time in the control group (P < .0001). Propensity score-matched comparison showed a 43.9% increase (95% confidence interval: 34.1%-53.8%) in CSA in the palmar warming group compared to the control group (P < .0001).

CONCLUSIONS

The palmar warming technique is effective at dilating the radial artery and may be a beneficial technique to facilitate transradial access.