Transradial Versus Transfemoral Coronary Intervention for Acute Myocardial Infarction Complicated by Cardiogenic Shock: Is Transradial Coronary Intervention Suitable for Emergency PCI in High-Risk Acute Myocardial Infarction?

Abstract: Background. Data are limited regarding the clinical results of transradial coronary intervention (TRI) in acute myocardial infarction (AMI) complicated by cardiogenic shock. Objective. The aim of this study was to compare the clinical results of TRI and transfemoral coronary intervention (TFI) in AMI patients who had cardiogenic shock and underwent emergency percutaneous coronary intervention (PCI). Methods. Between January 1, 2006, and August 31, 2012, a total of 507 consecutive patients with AMI underwent emergency PCI within 12 hours of onset. Eighty-five patients presented with cardiogenic shock and were enrolled. Among these patients, 60 underwent TRI and 25 underwent TFI. Outcome measures included the following: major bleeding and vascular complications; major adverse cardiac or cerebrovascular events (MACCE); all-cause death; door-to-balloon time; and PCI procedural success. Results. TRI had a significantly lower rate of major bleeding and vascular complications within 30 days (6.7% vs 28.0%; P<.05) and 1 year (log-rank P<.05) than TFI. No significant differences were observed between the two groups in the MACCE rate within 30 days (28.3% vs 44.0%; P=.21) and 1 year (log-rank P=.06), and the all-cause death rate within 30 days (26.7% vs 40.0%; P=.30) and 1 year (log-rank P=.09). In addition, TRI was not inferior to TFI in terms of door-to-balloon time (99.8 min vs 110.4 min; P=.30) and PCI procedural success (95.0% vs 96.0%; P>.99). Conclusion. TRI is associated with fewer major bleeding and vascular complications than TFI, and it appears suitable for both low- and high-risk AMI patients, especially when AMI is complicated by cardiogenic shock.

J INVASIVE CARDIOL 2014;26(5):196-202

Key words: bleeding, STEMI, cardiogenic shock

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Compared with drug therapy, percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) has reduced mortality and recurrent ischemia.¹ Since it was reported by Kiemeneij and Laarman, transradial coronary intervention (TRI) has been widely used,² particularly in Asia.^3,4 Although TRI requires a learning curve, it is capable of reducing bleeding and vascular complications at the access site.⁵ Furthermore, TRI has been reported to decrease myocardial infarction, cerebral infarction, and death.⁶ Although transfemoral coronary intervention (TFI) continues to be widely used, it has been associated with reports of bleeding and vascular complications more frequently than TRI.^7,8

Major bleeding complications in AMI are associated with an increased risk of death and the recurrence of ischemic events.^9-11 Avoidance of bleeding complications reportedly improves the survival rate in patients with AMI who undergo PCI.^12,13 On the other hand, cardiogenic shock is a life-threatening complication of AMI, occurring in 5%-10% of AMI patients.^14-16 The mortality of AMI complicated by cardiogenic shock is still high, even in cases that undergo early revascularization.^14,16-18 However, early recanalization by primary PCI is an independent predictor of improved hospital survival of AMI complicated by cardiogenic shock.^15,19-21

Several previous studies have compared TRI and TFI, and the usefulness of TRI has been established;^22-25 however, most previous studies that compared TRI and TFI excluded patients with cardiogenic shock.^22-25 Thus, in patients with AMI complicated by cardiogenic shock, it remains unclear which PCI access site is better.

The aim of this study was to compare the clinical results of TRI and TFI in AMI patients who had cardiogenic shock and underwent emergency PCI.

Methods

Study design and patients. This was a single-center, retrospective study of radial versus femoral access-site intervention. Patients were included in this study if they had AMI complicated by cardiogenic shock that resulted from a lesion in the target vessel, and underwent PCI within 12 hours of symptom onset. They were categorized by the access site used for the invasive approach; the selection of the site was at the discretion of the operators. Patients were ineligible for this study if the brachial artery was used. This study was approved by the ethics committee of Toho University Omori Medical Center.

AMI Definitions. ST-elevation myocardial infarction (STEMI) was defined as typical chest pain lasting >30 minutes with change in the electrocardiogram (ECG) that included either ST elevation of >1 mm in more than 2 contiguous ECG leads or new left bundle branch block (LBBB).

Non-ST elevation myocardial infarction (NSTEMI) was defined as having the same symptoms as STEMI, but with ST depression of >0.5 mm, dynamic T-wave inversion or ST elevation <1 mm on the ECG, and elevation of myocardial enzymes.²⁶

Cardiogenic shock was defined as systolic blood pressure that was persistently <90 mm Hg, or the need for inotropic support or intraaortic balloon pump (IABP) in order to maintain a systolic blood pressure >90 mm Hg in the presence of systemic hypoperfusion and adequate left ventricular filling pressure.²⁷

Procedures and postintervention treatment. For PCI, a 6 or 7 Fr sheath was inserted into the radial or femoral artery, 5000 U of heparin were administered intraarterially, and coronary angiography (CAG) was performed. Angiography of the contralateral coronary artery was performed first, and the collateral circulation was assessed by the Rentrop classification. After the guidewire had crossed the lesion, stenting was performed after plain old balloon angioplasty (POBA). The selection of access site and the size, length, and type of stent used was determined by the operator. For most procedures, bare-metal stents were implanted. In cases that required IABP or percutaneous cardiopulmonary support (PCPS), the IABP and/or PCPS catheters were inserted via femoral approach, before the PCI procedure and after administration of heparin. Support devices were not used in cases where hemodynamics were maintained by inotropic support, as the priority with those was rapid revascularization.

After the procedure, all patients received life-long oral aspirin (100 mg) and oral clopidogrel (75 mg/day) or ticlopidine (200 mg/day) for at least 1 month. None of the patients received glycoprotein IIb/IIIa inhibitors because they are not approved for use in Japan.

Quantitative coronary angiography (QCA). Quantitative evaluation of coronary angiograms was conducted using the CCIP310 system (Gadelius Medical Co). Diastolic frames were taken at the angle that showed less shrinkage of lesions; the same angle was used before and after treatment for recording the image.

Outcome measures. The outcome measures were as follows: major bleeding and vascular complications within 30 days and 1 year; major adverse cardiac or cerebrovascular events (MACCE) within 30 days and 1 year; all-cause death within 30 days and 1 year; door-to-balloon time; PCI procedural success; and length of hospital stay.

Major bleeding and vascular complications were defined as follows: access-site hemorrhage/hematoma requiring transfusion, delaying hospital discharge, or resulting in death; proved false aneurysm formation; intracranial bleeding; intraocular bleeding; retroperitoneal bleeding; or any other bleeding requiring transfusion not related CABG.^22,28,29 Furthermore, we classified them as PCI access-site related and non-PCI access-site related.

MACCE was defined as follows: death; stroke; emergency coronary artery bypass grafting (CABG); reinfarction or stent thrombosis; or target vessel revascularization.^28,30

Procedural success was defined as the achievement of a TIMI-3 flow grade and residual stenosis <30% (by visual angiographic assessment).^27,28

Statistical analysis. Statistical analysis was performed with statistical software (SPSS version 20, IBM). Data are presented as the number of patients, ratio (%), frequency (%), or mean ± standard deviation. Continuous variables were compared by the t-test, and categorical variables were compared using the χ²-test. Cumulative survival free of adverse events during the chronic phase was determined using the Kaplan-Meier method, and survival curves were compared by the log-rank test. The differences between groups were considered significant when P-values were <.05.

Results

Patients. From January 1, 2006, to August 31, 2012, a total of 507 consecutive patients with AMI underwent PCI within 12 hours of symptom onset. A total of 85 patients presented with cardiogenic shock and were enrolled in this study. Among these patients, 60 underwent TRI and 25 underwent TFI. The rates of access-site crossover were 1.7% (n = 1) in the TRI group and 0% in the TFI group. In the 1 patient who crossed over, the approach site was changed from radial to femoral because of subclavian tortuosity.

Baseline patient characteristics. No significant differences were observed between the two groups in age, sex, coronary risk factors, left ventricular ejection fraction (LVEF), blood pressure at admission, or time from symptoms to arrival (Table 1).

Angiographic and procedural characteristics. Angiographic and procedural characteristics, including the target vessel, initial TIMI flow grade, collateral flow based on the Rentrop grade, number of stents, size of the stents, volume of contrast media, amount of radiation and exposure time, and the use of IABP and PCPS were similar for both groups (Table 2). 

Oral medication use. No significant difference was observed between the two groups in oral medication use in the hospital or after discharge (Table 3).

Outcome measures. Compared with TFI, TRI had a significantly lower rate of major bleeding and vascular complications within 30 days (6.7% vs 28.0%, respectively; P<.05) (Figure 1). As for PCI access-site related complications, TRI complications were significantly lower than TFI complications (0% vs 12.0%, respectively; P<.05). In contrast, there was no significant difference for non-PCI access-site related complications (6.7% vs 16.0%; P=.23). The incidence of support-device related hemorrhage/hematoma was 3.3%, false aneurysm formation was 1.7%, and other bleeding unrelated to CABG was 1.7% for TRI, whereas support-device related hemorrhage/hematoma was 8.0% and intracranial bleeding was 8.0% in the cases with TFI. The false aneurysm formation in the TRI group was related to the placement of a support device. Other bleeding that was unrelated to CABG in the TRI group was due to gastrointestinal hemorrhage (Table 4). Kaplan-Meier curves of the cumulative incidence of major bleeding and vascular complications within 1 year are shown in Figure 2. Compared with TFI, the TRI group had a significantly lower rate of major bleeding and vascular complications within 1 year (log-rank P<.01) (Figure 2). 

No significant differences were observed between the TRI and TFI groups in the rate of MACCE within 30 days (28.3% vs 44.0%, respectively; P=.21) or all-cause death within 30 days (26.7% vs 40.0%, respectively; P=.30) (Table 4). Furthermore, the TRI group had lower rates of both MACCE and all-cause death within 1 year than the TFI group; however, these differences did not reach statistical significance (log-rank P=.06 and P=.09, respectively) (Figure 3).

Additionally, no significant differences were found between the TRI and TFI groups in the door-to-balloon time (99.8 min vs 110.4 min, respectively; P=.30) and PCI procedural success rate (95.0% vs 96.0%, respectively; P>.99) (Table 5). Furthermore, TRI led to a shorter length of hospital stay than TFI (32.5 days vs 43.1 days, respectively); however, the difference was not significant (P=.40) (Table 5).

 Other clinical results were also similar between the two groups (Table 5).

Discussion

Several clinical studies have compared the results of TRI and TFI in patients with AMI; however, most of these reports excluded shock cases.^22-25 Patients with AMI complicated by cardiogenic shock have a worse clinical course, and shock has been reported to predict mortality.^18,21 In the real world, PCI has been performed even in patients with AMI complicated by cardiogenic shock, although the influence of access-site remains unclear. Therefore, in the present study, we compared the clinical results of TRI and TFI in AMI patients who had cardiogenic shock and underwent emergency PCI.

Major bleeding and vascular complications within 30 days and 1 year. Multiple potent antiplatelet drugs are routinely given to patients with AMI; therefore, it is not surprising that bleeding and vascular complications often develop in patients who undergo TFI.^31,32 Compared with the femoral artery, the radial artery is more superficial, surrounded by less subcutaneous tissue, and has a smaller diameter. A small diameter is an important predictive factor for maintaining homeostasis of the access site after removal of the sheath, even when anticoagulants are given systemically.^6,33 Several studies have reported that both reductions in bleeding and vascular complications are associated with improved clinical outcomes, especially in AMI patients.^22,23,34 In this study, the incidence of major bleeding and vascular complications was higher than in previous studies in AMI patients without cardiogenic shock; however, the incidence of these complications in the present study was similar to previous reports where AMI was complicated by cardiogenic shock.^22-24,35 Furthermore, compared with TFI, the TRI group was associated with significantly less major bleeding and vascular complications within 30 days and 1 year.

When major bleeding complications develop, it is desirable to correct them by transfusion. This is especially important in patients with cardiogenic shock.³⁶ However, blood transfusion itself increases the risk of mortality in AMI patients.³⁷ This might be due in part to alterations in erythrocyte nitric oxide biology in transfused blood that leads to initial vasoconstriction, platelet aggregation, and ineffective oxygen transportation. In addition, hemorrhage as well as blood transfusion by themselves can cause inflammation.³⁷ Thus, it is important that TRI reduces the need for blood transfusion and its associated mortality risk.

IABP is the mechanical support device currently used most widely for the treatment of cardiogenic shock. The use of the IABP for cardiogenic shock is recommended in both American College of Cardiology/American Heart Association (class IB evidence) and European Society of Cardiology guidelines (class IC evidence).^38,39 However, if IABP is used, there is a further risk of bleeding complications.^35,40 Additionally, PCPS is also used as a support device in cases of cardiogenic shock, and no significant difference was apparent between the two groups in PCPS use (Table 2). If PCPS is used, the risk of bleeding complications will obviously increase.⁴¹ In cases that require PCPS, IABP is often used at the same time, and the risk of bleeding complications should increase even further. TRI does not reduce the added bleeding risk from the IABP and/or PCPS; however, TRI is able to reduce the total risk of access-site bleeding complications in the patients who received IABP and/or PCPS. In addition, when PCPS and IABP are used together, both femoral arteries are needed to insert these devices, therefore, TRI is more useful in this situation.

Moreover, as in the RACE study conducted in North Carolina, if AMI patients who have not yet arrived at a PCI emergency center cannot immediately undergo PCI, fibrinolytic therapy may be carried out prior to transport.⁴² Since there is also a further risk of bleeding complications in such cases, TRI is recommended under these circumstances as well.

MACCE and all-cause death within 30 days and 1 year. Cardiogenic shock has been reported to be an independent predictor of MACCE and mortality.²⁷ In the present study, the overall rates of MACCE and mortality were similar to those in previous studies in patients with AMI complicated by cardiogenic shock.^27,43 Both the rates of MACCE and mortality within 30 days and 1 year were higher in the TFI group than in the TRI group; however, these differences were not significant. The development of bleeding complications is an independent risk factor for both MACCE and in-hospital mortality.²⁹ Although we observed less bleeding in the TRI group, no difference in mortality within 1 month was observed between the two groups. Since AMI complicated by cardiogenic shock has a high in-hospital mortality,^14,16,19 it is possible that a difference in mortality due to bleeding complications was masked by the effect of cardiogenic shock on the mortality rate in both groups.

Door-to-balloon time and PCI procedural success. To achieve rapid revascularization, TFI is still used for PCI in patients with AMI.⁴⁴ The learning curve for TRI is greater than for TFI, and it has been reported that the rate of access-site crossover is higher in TRI.^22,23 This is especially true in shock cases, when it is difficult to palpate a pulse in the radial artery. Door-to-balloon times have been shown to be an independent predictor of mortality.⁴⁵ In this study, no significant difference was observed in the door-to-balloon time between TRI and TFI. In addition, the procedural success rate was 95.3% in the entire cohort. This success rate is similar to previous studies of AMI that either excluded or included cardiogenic shock cases.^22-24 Furthermore, in the present study, the procedural success rate was similar between the TRI and TFI groups. According to a previous report, a higher success rate and skill in PCI can be acquired by the systematic use of TRI. Therefore, we suggest that TRI is able to be used as the primary access site in most AMI patients.⁴⁶

Moreover, in the RIVAL trial, it was suggested that the benefits of TRI over TFI include a higher level of experience and expertise by the operators performing TRI.²² Accordingly, PCI was performed largely with TRI by four very experienced operators at our center, and we believe this will lead to increased skill and experience.

Length of hospital stay. In previous studies, TRI was shown to shorten the duration of hospitalization, improve quality of life, and reduce the cost of catheterization.^47,48 However, in our study, no significant difference was found between the two groups in the length of hospital stay. The overall average length of hospital stay in our study was 35.6 days, and this prolonged duration of hospitalization was probably due to the fact that all patients enrolled in the study had cardiogenic shock.

Study limitations. This study did have some limitations that deserve consideration. First, our center generally performed PCI using TRI at the time this study was initiated. Since the operators were well trained in the use of TRI, it is possible that this training influenced the results. Therefore, it may be difficult to generalize these results to centers that do not perform TRI on a routine basis. Second, the access site for PCI was chosen by the operators; thus, some selection bias may have been possible. However, PCPS was used in the most severe cases, and no significant difference was apparent between the two groups. PCPS was used in more than 20% of the cases in the TRI group (Table 2), and this indicates that operators did not avoid TRI based on the severity of the patient’s condition. Finally, this was a retrospective analysis of a non-randomized, single-center experience, and the sample size was relatively small. Thus, further prospective multicenter studies are needed to confirm our results.

Conclusion

From our clinical results, TRI was associated with fewer major bleeding and vascular complications than TFI. Furthermore, TRI was not inferior to TFI with respect to MACCE and mortality at both 30 days and 1 year. Therefore, we believe that TRI is suitable for AMI complicated by cardiogenic shock.

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________________________________

From ¹Division of Cardiovascular Medicine, Department of Internal Medicine, the Faculty of Medicine, Toho University, Tokyo and ²Tsukuba Heart Center, Tsukuba Memorial Hospital, Tsukuba, Japan.

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 July 12, 2013, provisional acceptance given August 14, 2013, final version accepted October 7, 2013.

Address for correspondence: Atsushi Iga, MD, Division of Cardiovascular Medicine, Department of Internal Medicine, the Faculty of Medicine, Toho University, 6-11-1 Ohmorinishi Ota-ku, Tokyo 143-8541, Japan. Email: atsushi.iga-toho-303@med.toho-u.ac.jp