Complete Transitioning to the Radial Approach for Primary Percutaneous Coronary Intervention: A Real-World Single-Center Registry of 1808 Consecutive Patients With Acute ST-Elevation Myocardial Infarction

Abstract: Objectives. To compare the short- and long-term outcomes of transradial approach (TRA) versus transfemoral approach (TFA) for primary percutaneous coronary intervention (PPCI) during a complete institutional transition from TFA to TRA. Methods and Results. An all-comer population of ST-elevation myocardial infarction (STEMI) patients (n=1808) who underwent PPCI using TRA (n=1162) and TFA (n=646) from October 2007 to December 2010 were enrolled. TRA was used in 25% of PPCIs by 2007 and in 96% of PPCIs in 2010. Primary endpoints were cardiovascular death and major adverse cardiac event (MACE), defined as a composite of death, stroke, reinfarction, and target vessel revascularization at 30 days and 1 year. At 30 days, TRA compared to TFA was associated with a significant reduction of  cardiovascular mortality (5.2% vs 10.5%; P<.001), significant MACE reduction (7.3% vs 12.5%; P<.001), fewer access-site complications (0.9% vs 8.2%; P<.001), and lower TIMI major bleeding (1.1% vs 4.3%; P<.001). At 1 year, the cardiovascular mortality and MACE rates were also in favor of the TRA group (6.9% vs 11.5%; P<.001 and 11.6% vs 20.1%; P<.001), respectively. Conclusion. Complete transition from femoral access to a preferred radial access is safe and effective for STEMI patients undergoing PPCI, with a favorable effect on short- and long-term outcomes.  

J INVASIVE CARDIOL 2014;26(9):475-482

Key words: primary percutaneous coronary intervention, ST-elevation myocardial infarction; transradial approach

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Primary percutaneous coronary intervention (PPCI) is an optimal strategy to re-open the occluded coronary artery (culprit vessel) and improves the outcomes of patients with ST-elevation myocardial infarction (STEMI).^1-3 Access-site selection is an important procedural issue in PPCI. Transfemoral approach (TFA) has been associated with higher rate of access-site bleeding and vascular complications in comparison with transradial approach (TRA). This has been particularly evident with the aggressive use of antithrombotic and antiplatelet treatment in patients with acute coronary syndrome.^4,5 Vascular access-site complications have been shown to be associated with worse outcomes.^6,7

Whether there is a possibility to further improve the outcomes with preferred radial access instead of femoral access in an all-comer STEMI population remains to be assessed. 

Recent randomized trials found that TRA has been associated with fewer bleeding events, fewer vascular access-site complications, and better clinical outcomes compared with TFA in acute STEMI patients undergoing PPCI.^8,9 

The radial artery is advantageous because it is readily accessible due to its superficial anatomy, regardless of patient body mass index, and because of its close proximity to the radial bone, which makes hemostasis easier.¹⁰

The change of access-site strategy, from preferred femoral access to preferred radial access, can overcome most of the problems related to the arterial access choice.¹¹ Since 2005, TRA has been gradually adopted at our center; in 2009, TRA became the main access choice and has replaced femoral access in most of the elective and emergency PCI procedures. 

The objective of this study was to compare the outcomes of a large-scale cohort of STEMI patients undergoing PPCI during a complete institutional transition from TFA to TRA as the preferred access. All procedures were performed by the same seven high-volume operators who were experienced in TFA before adopting routine TRA. 

Methods

Study population. Between October 2007 and December 2010, a total of 1808 consecutive patients with acute STEMI admitted within the first 12 hours of symptom onset undergoing PPCI were enrolled. There were 1162 TRA and 646 TFA patients. Over 39 months, an all-comer population of STEMI patients treated at our center were recruited and the procedural and clinical data were recorded.

The preferred usage of radial artery access as an alternative to femoral artery access for PPCI was adopted at our center between the period of 2007 to 2010. In 2007, TRA was performed in 25% of all PPCIs. In 2010, TRA was used in 96% of all PPCIs. Our PPCI registry is the representative of our national interventional practice and contains data from 80% of the PPCIs in the Republic of Macedonia, which has a population of two million.

Procedural data were entered into a dedicated database by the interventional cardiologist immediately after the completion of the procedure. These data were open for evaluation and audit by the health administration and public health insurance administration. 

Transitioning from preferred femoral access to preferred radial access. All seven operators were experienced in TFA, and went through the TRA learning curve with more than 100 elective PCI procedures per year before commencing TRA for PPCI. At the beginning of the study (2007), TFA was the preferred access site (75%). Over the mid-term of the study (the transitional period), all operators changed preferred access to TRA, and reached 96% of all procedures in 2010.

Vascular access. Femoral artery access was obtained with a modified Seldinger technique. After local infiltration with 3-5 mL 2% lidocaine, the femoral artery was cannulated with 17 G needle and 0.035˝ guidewire, followed by 10 cm, 6 Fr introducer sheath placement.

The radial artery was accessed after local infiltration with 1-1.5 mL 2% lidocaine, using counter-puncture technique with a 20 G plastic intravenous cannula and 0.025˝ mini guidewire (45 cm) and followed by 5 Fr or 6 Fr hydrophilic introducer sheath (Terumo Corporation) placement. Spasmolytic cocktail (5 mg verapamil) was given intraarterially through the radial sheath.

Interventional procedures. Standard guide catheters were used to perform PPCI (standard shapes like Judkins, EBU, Amplatz, etc), mostly 6 Fr and occasionally 5 Fr, for both radial as well as femoral artery access. Standard guidewires for PCI, mostly Balance Middle Weight  (Abbott Vascular), were used according to case specificity, without access-strategy related preference. Stent choice between drug-eluting and bare-metal was left to operator discretion. Manual thrombus aspiration was performed in cases with evidently high thrombus burden. 

PCI only on the infarct-related artery was recommended. Infarct-related artery flow was determined before and after the PPCI procedure using the TIMI (Thrombolysis in Myocardial Infarction) score.¹² Data were analyzed by intention-to-treat principle.

Anticoagulation and antiplatelet treatments. Before PPCI, patients were treated with intravenous bolus of unfractionated heparin (100 IU/kg), aspirin (300 mg followed by 100 mg/day indefinitely) and clopidogrel loading dose (600 mg followed by 75 mg/day for at least 1 year). When required, abciximab was given by intracoronary administration or intravenous bolus of 0.25 mg/kg followed by 0.125 µg/kg/min infusion for 12 hours using weight-adjusted protocol. After completion of PCI, weight-adjusted dosage protocol of heparin infusion was continued for 24 hours. No fibrinolytic agent was used. 

Hemostasis management. Femoral group: the femoral artery sheath was removed 3-4 hours after sheath insertion and hemostasis was achieved by manual compression of 15-20 min followed by prolonged weight compression placement. The patient must remain in bed thereafter, with restricted mobility, for the following 6 hours (9-10 hours in total from the sheath insertion). Vascular closure devices were not used. Radial group: the radial artery sheath was removed immediately after the procedure and hemostasis was achieved by a simple bandage compression or TR band (Terumo Corporation). Patients had no mobility restriction after the procedure. Simple bandage compression was applied with 4-6 small elastic bands compressing the radial artery at the puncture site. The TR band was applied by inflating 13-15 mL of air at the puncture site. After each hour, the TR band was gradually deflated and totally removed after 4 hours. Patients had no mobility restriction after the procedure.

Study endpoints. The primary clinical endpoints were cardiovascular death rate and major adverse cardiac event (MACE) at 30 days and 12 months of follow-up. Secondary endpoints were major vascular access-site complications and TIMI major bleeding at 30 days. Other baseline, clinical, and procedural characteristics, such as demographic data, risk factors, first medical contact to balloon time, procedure time, procedural success, and fluoroscopy time were recorded and compared between groups. Primary and secondary endpoints were judged by an independent clinical event committee that was blinded to the clinical data.

Definitions. Cardiovascular death were defined as acute myocardial infarction, sudden cardiac death, death due to heart failure, death due to stroke, death due to cardiovascular procedures, death due to cardiovascular hemorrhage (intrapericardial bleed with cardiac tamponade), or death due to other cardiovascular causes within 30 days and 1 year after the index procedure. MACE was defined as a composite of death, stroke, reinfarction, and target vessel revascularization at 30 days and 1 year follow-up. Major vascular access-site complication was defined as any access-site related hemorrhage requiring red blood cell transfusion, delayed hospital discharge, or a surgical vascular repair.¹³TIMI major bleeding was defined as overt clinical bleeding (or documented intracranial or retroperitoneal hemorrhage) associated with a drop in hemoglobin of 5 g/dL (0.5 g/L) or drop in hematocrit of 15%.¹⁴Door-to-balloon time was defined as the time from admission until the first balloon inflation at the culprit lesion.¹⁵Procedural success was determined by angiographic success, defined as the achievement of a minimum stenosis diameter reduction to <20% in the presence of grade 3 TIMI flow. ¹⁶Procedural time was calculated as the time needed from the local anesthesia injection until guide catheter removal. Fluoroscopy time was also recorded. 

Statistical analysis. Data were expressed as mean ± standard deviation for normally distributed numeric variables, or reported as median (minimum-maximum) when the data did not fit a normal distribution. Percentages were used to express categorical variables. Categorical variables were compared with chi-square test or Fisher’s exact test. Student’s t-test or Mann Whitney U-test were used to compare differences between two groups (continuous data) when appropriate. Treatment effects between TFA and TRA groups were analyzed by univariate log-regression and reported as odds ratio (OR) with the corresponding 95% confidence interval (CI) calculated for the endpoints. Time-to-event survival curves are displayed according to the Kaplan-Meier method and compared by Mantel-Cox log rank analysis. All reported P-values are two-sided and P-values of <.05 were considered to identify statistically significant differences. All statistical analysis was performed using PASW SPSS.¹⁸

Results 

Over 39 months (between October 2007 and December 2010), there were 1808 consecutive PPCIs for STEMI patients treated at our center; a total of 1162 patients were treated with TRA (64.3%) and 646 patients with TFA (35.7%). The mean age of all patients was 58 years (range, 28-89 years) and most (75%) were male. Smoking was more common in TRA patients (P=.01). The symptom onset to first medical contact time and door-to-balloon time were similar in both groups (P=.37 and P=.68, respectively). Patients with cardiogenic shock on initial presentation were similar between the groups (P=.90). Intraaortic balloon support during the procedure was performed in only 0.3% of patients. Baseline characteristics are shown in Table 1.

In both groups, the left anterior descending artery was the most frequent infarct-related artery. Although baseline TIMI flow grade 0-1 was higher in the TFA group (P=.01), the final TIMI 3 flow was similar between TRA and TFA groups (95% and 94%, respectively; P=.38). Procedural success was obtained in 95% and 96% of the TRA and TFA groups, respectively. The use of abciximab was only 4.1%. Procedural characteristics are shown in Table 2. 

During the course of the study, a major shift occurred in access-site preference and we have changed the strategy from femoral to radial access as a preferred access choice for all patients. Crossover from radial to femoral access peaked at 5.8% in 2008 and subsequently declined to only 1.6% in 2010. The graph of access site changing over time and crossover rate is illustrated on Figure 1.

Primary and secondary endpoints. Compared to TFA, the TRA route was associated with lower cardiovascular mortality at 30 days and 1 year (5.2% vs 10.5%; OR, 0.46; 95% CI, 0.32-0.66; P<.001 and 6.9% vs 11.5%; OR, 0.57; 95% CI, 0.41-0.79; P=.01). 

The MACE rates at 30 days and 1 year were significantly lower in the TRA group compared to the TFA group (7.3% vs 12.5%; OR, 0.55; 95% CI, 0.39-0.76; P<.001 and 11.6% vs 20.1%; OR, 0.52; 95% CI, 0.40-0.68; P<.001), respectively (Figure 2 and Figure 3).

A markedly lower major vascular access-site complication rate was seen in TRA patients compared to TFA patients (0.9% vs 8.2%; OR, 0.11; 95% CI, 0.05-0.20; P<.001). At 30-day follow-up, TIMI major bleeding rate was significantly lower in the TRA group compared to the TFA group (1.1% vs 4.3%; OR, 0.24; 95% CI, 0.12-0.46; P<.001). Study endpoints are displayed in Table 3.

Event-free survival. The Kaplan-Meier survival curves are shown in Figure 4 and Figure 5. After 30-day and 1-year follow-up, the TRA patients had an improved cumulative survival compared to TFA patients (log-rank test, P<.001 and P=.01, respectively). Furthermore, the benefit of TRA was seen in the entire spectrum of patients (Figure 6).

At 1-year follow-up, the overall cardiovascular mortality rate was 10%. The cardiovascular mortality rate was significantly lower in the TRA group compared to the TFA group (6.9% vs 11.5%; P<.001).

Discussion

The present study is the first large-scale single-center report analyzing the impact of transitioning the access from femoral to a preferred radial access on cardiovascular mortality, bleeding events, and 1-year clinical outcomes in all-comer STEMI patients undergoing PPCI. 

Access site is associated with bleeding events, while bleeding itself has been associated with an increased risk of death and ischemic events.¹⁷ From the present study, the advantage of TRA compared to TFA was seen by the lower MACE rate after 30 days (P<.001) and at 1-year clinical follow-up (P<.001). Specifically, radial access was associated with lower rates of 30-day and 1-year cardiovascular mortality (5.2% vs 10.2%; P<.001 and 6.9% vs 11.5%; P<.001). The lower 30-day cardiovascular death rate associated with TRA was also seen in the RIFLE-STEACS study (5.2% vs 9.2%; P=.02),⁹ as well as in the STEMI subgroup of RIVAL (1.3% vs 3.2%; P=.01).¹⁸

A recent meta-analysis of 9 randomized controlled studies involving 2977 patients suggested that the TRA is associated with a 47% reduction in mortality and a 38% reduction in MACE in STEMI patients undergoing PCI. ¹⁹

Similarly, analysis of the North American National Cardiovascular Data Registry Cath-PCI registry, which included 90,879 patients who underwent either primary or rescue PCI for STEMI showed that TRA was independently associated with reduction of in-hospital mortality (OR, 0.76; 95% CI, 0.57-0.99) and of bleeding (OR, 0.62; 95% CI, 0.53-0.72).²⁰

Finally, the analysis of 46,128 PPCI cases recorded in the British Cardiovascular Intervention Society database over a 5-year period suggested that TRA was independently associated with a lower 30-day mortality (hazard ratio [HR], 0.71; P<.05), in-hospital major adverse cardiac and cardiovascular event (HR, 0.73; P<.05), major bleeding (HR, 0.37; P<.01), and access-site complications (HR, 0.38; P<.01).²¹

Although the underlying mechanisms of increased mortality of patients with major bleeding remain unclear, increased myocardial ischemia has been proposed to be a final common pathway. Local bleeding and femoral site hematoma formation are also thought to lead to systemic activation of prothrombotic pathways and activation of the clotting cascade. Cessation of antithrombotic therapies, in blood loss and consequences of blood transfusion, could further increase the risk of stent thrombosis and subsequent myocardial ischemia and reinfarction. ²² 

Consistent with the result from the RIVAL study,²³ other advantages of TRA (as shown in this study) included a significantly lower major vascular access-site complication rate compared to TFA (0.9% vs 8.2%; P<.001). Interestingly, the dramatic reduction of access-site complications by TRA was associated with lower MACE rate at 30 days compared to the TFA group (OR, 0.55; 95% CI,  0.39-0.76; P<.001). The reduction of TIMI major bleeding and major access-site complications seen in the TRA group most likely affected the short and long-term mortality, and were associated with improved clinical outcomes. 

Since prolonged bed rest itself seems to be a predictor of worse prognosis in coronary artery disease,²⁴ the possibility of a more rapid mobilization as a result of the decrease in access-site complications might have also influenced the outcome difference. Alternatively, it is likely that subclinical bleeding in a less mobile, less active, less vigorous, and bedridden patient after femoral artery instrumentation with resultant hematoma might lead to platelet activation, precipitating intravascular thrombosis. The controversial question is whether relatively minor episodes of bleeding are actually responsible for later mortality. The reduction in cardiac mortality and bleeding found in the radial arm of the RIFLE-STEACS⁹ and in the STEMI subgroup of RIVAL¹⁸ support the link between mortality and clinically relevant access-site bleeding. Further study is required in order to answer this question with confidence.

The advantage of TRA in acute myocardial infarction was also seen in some randomized trials with a follow-up period ranging from 30 days to 2 years. All the studies showed a favorable clinical outcome and fewer access-site complications for TRA compared to TFA.^8,9,25,26

Some studies argue that use of vascular closure devices (VCDs) for TFA could lower the access-site complications.^27,28 Several VCDs have been introduced and tested in clinical trials, but none have yet convincingly shown the ability to reduce major vascular complications compared with manual compression. Furthermore, a meta-analysis reported that the use of VCD increases the rate of vascular complications.²⁹ Recently, in a multicenter registry of 112,340 patients, Trimarchi et al reported that the adoption of VCDs was associated with an increased risk of the development of retroperitoneal hematoma. ³⁰ The American Heart Association places the VCDs in class III when used with the purpose of reducing vascular complications.³¹ In our study, we did not use any VCDs in the TFA group.

The HORIZONS-AMI study⁵ showed an improved event-free survival rate in patients undergoing PPCI by TRA and confirmed the advantage of TRA with regard to hemorrhagic complications also in patients treated with bivalirudin. However, the study was underpowered due to the small sample size (n=200). 

During the course of the study, a major shift occurred in access-site preference at our institution by changing the strategy from predominantly femoral to radial access as the preferred approach in almost all PPCI procedures. The transition occurred rapidly and safely, with a crossover from radial to femoral access that peaked at 5.8% in 2008 and subsequently declined to a much lower 1.6% rate in 2010 (Figure 1).

The present study showed that TRA did not increase the time interval measures, such as door-to-balloon time, procedural time, and fluoroscopy time. Similar result was shown by another study. ²² However, we consider that time manner for TRA relates to operator experience. Based on our experience, the TRA requires a specific set of skills, and is associated with a significant learning curve. To achieve the best results in TRA interventions, individual operators and institutional teams should aim to maintain the highest feasible rate of TRA. A stepwise approach to learning is proposed according to clinical characteristics and PCI difficulty. Acute coronary syndrome (ACS) PCI is proposed as the last step (non-ST elevation ACS and STEMI patients), due to multifaceted clinical settings and PCI complexity. The highest level of competency is obtained when patients requiring complex clinical management can be managed with timely and technically proficient control of PCI, irrespective of vascular access anatomy. After the learning curve has been completed, for over 50% TRA in routine practice, a minimum of 80 procedures/year per operator is recommended.³²

Furthermore, the use of a dedicated radial kit (hydrophilic sheath, wire, and cannula needle) is the key element in radial artery cannulation, while catheter manipulation will be easier after dealing with the learning curve, particularly for experienced transfemoral operators. 

Other advantages of TRA that have been reported include earlier patient mobilization, reduced procedural and hospital costs,³³ and equal operator radiation exposure compared to femoral approach.³⁴

Finally, the advantage of TRA compared to TFA was seen in the entire spectrum of patients in the present study, including lower-risk patients, such as age <65 years, non-diabetic, female, non-multivessel diseased, non-anterior MI, first medical contact to balloon time <120 min, door-to-balloon <60 min, and preprocedural and postprocedural TIMI 2-3 flow (Figure 4). 

The results of this study are in tune with the recent 2012 European Society of Cardiology guidelines for STEMI,³⁵ where TRA is preferred over TFA for PPCI, if performed by an experienced operator (class IIa, level B). These guidelines are based on data derived from the RIFLE-STEACS trial⁹ and the STEMI subgroup of the RIVAL trial.¹⁹ 

Study limitations. Several limitations of the present study should be discussed. First, this was an observational analysis and there was no randomized comparison between TRA and TFA. Second, the use of radial access has changed over the course of the study and therefore the learning curve might have potential interaction effects on outcomes. Finally, bivalirudin was not used in our population; therefore, the result of this study is not representative for centers with  high use of bivalirudin. 

Conclusion

Complete transition from femoral access to a preferred radial access is safe and effective in the setting of primary PCI in an all-comer population of STEMI patients, with a favorable effect on short- and long-term outcomes. Experienced primary PCI centers could further improve their performance by adopting preferred TRA in STEMI interventions. However, these results should be confirmed in an adequately powered, prospective, randomized trial comparing radial and femoral approaches for PCI in STEMI.

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_______________________________________

From the ¹University Clinic of Cardiology, Medical Faculty, University of St. Cyril & Methodius, Skopje, Macedonia; and ²Department of Cardiology and Vascular
Medicine, Faculty of Medicine, University of Indonesia, National Cardiovascular Center Harapan Kita, Jakarta, Indonesia.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted September 12, 2013, provisional acceptance given November 4, 2013, final version accepted February 3, 2014.

Address for correspondence: Prof Sasko Kedev, University Clinic of Cardiology, Interventional Cardiology, Vodnjanska 17, Skopje, Macedonia 1000. Email: skedev@mt.net.mk