Transradial PCI in Women: Problem Solved or Clinical Equipoise?

Bleeding complications that occur after percutaneous coronary intervention (PCI) are associated with increased morbidity and mortality.¹ Studies indicate that certain populations are at higher risk for bleeding: the elderly, patients with renal insufficiency and women.² Female sex has been consistently identified as a risk factor for hemorrhagic complications in the setting of acute coronary syndrome (ACS),² elective PCI³ and ST-segment elevation myocardial infarction.⁴ Several strategies may reduce bleeding risk after PCI such as appropriate dosing of antithrombotic medications,⁵ use of bivalirudin⁶ and the radial approach,⁷ but these strategies have not been comprehensively studied in women. Changing vascular access to the radial approach, in particular, remains poorly studied in many subgroups, including women. Although it is associated with marked reductions in procedural bleeding, transradial PCI may be more challenging in women due to smaller body habitus and smaller-caliber radial arteries,⁸ making arterial access difficult and potentially increasing spasm. In this issue of the Journal of Invasive Cardiology, Maddury and colleagues describe a single-center experience with transradial PCI in women.⁹ While there was no control arm and a cohort of 2,3 The mechanisms underlying this increased risk are not clear, but inappropriate dosing of antithrombin and glycoprotein (GP) IIb/IIIa inhibitors may be partially responsible. Alexander et al examined data from the CRUSADE registry and demonstrated that females are significantly more likely to be overdosed with unfractionated heparin, low-molecular-weight heparin and GP IIb/IIIa inhibitors, and were at increased risk for bleeding due to the higher doses used.¹⁰ However, this inappropriate dosing accounted for only 25% of the increased bleeding risk. The remainder of the risk could not be easily accounted for by data captured in the registry. This raises a second issue regarding what proportion of bleeding risk is attributable specifically to access-site bleeding and whether a vascular access strategy could further reduce bleeding risk in women undergoing PCI — even, potentially, in the setting of high-dose anticoagulant therapies. Examination of clinical trial data demonstrates that the majority of bleeding complications among PCI patients are related to the arteriotomy. In contrast, access-site bleeding accounts for a smaller proportion of bleeding in patients with ACS due to some patients not undergoing revascularization.¹¹ The consistency of these data across trials indicates that the most effective way to reduce bleeding is to eliminate access-site bleeding by using the radial approach. Randomized trials and observational studies show that transradial PCI is associated with a near-70% reduction in bleeding risk compared with transfemoral PCI.⁷ Despite this marked safety profile, data from the National Cardiovascular Data Registry show that females are much less likely to undergo transradial PCI compared with males.¹² There are some potential reasons for this disparity. One major reason is that the radial approach is associated with a higher risk of procedural failure compared with the femoral approach.⁷ While it is not known if the rate of transradial procedural failure is higher in women, studies indicate that women have smaller radial arteries⁸ that are more prone to spasm.¹³ This can make radial access more difficult, and an examination of 2,600 consecutive radial cases with a 4.3% procedural failure rate showed that 43% of the procedural failures were due to either inadequate arterial puncture or radial artery spasm.¹⁴ Some of these challenges can be overcome with greater radial experience, but the overall rate of transradial PCI remains low in the United States compared to other countries.¹⁵ The greater use of the radial approach in Asia and the high degree of proficiency may explain why there were only 2 cases in the study by Maddury et al that required conversion to the femoral approach. It is unclear whether, in either of these cases, conversion from the right to the left radial approach was considered. Interestingly, in women and short-stature patients, tortuosity and catheter fit may be more challenging from the right radial without such difficulties from the left radial.¹⁶ Finally, even in experienced centers, females are at higher risk for local bleeding complications after transradial PCI such as forearm hematomas.¹⁷ The Maddury et al study serves as a reminder that females are at higher risk for bleeding and vascular complications after PCI compared with men. While the radial approach is associated with a reduction in bleeding risk, it is conversely associated with a higher risk of procedural failure, which may be augmented in women. Therefore, more data are needed before transradial PCI can be considered as a panacea for post-PCI complications in females. This equipoise calls for a dedicated randomized trial comparing radial and femoral approaches in women undergoing PCI.

References

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———————————————————— From the Duke Clinical Research Institute and Duke University Medical Center, Durham, North Carolina. Disclosure: Dr. Rao is a consultant to Terumo Medical. Address for correspondence: Sunil V. Rao, MD, 508 Fulton Street (111A), Durham, NC 27705. E-mail: sunil.rao@duke.edu