radial vs femoral access

The MATRIX Trial: AKI After Radial or Femoral Access for Invasive ACS Management

November 15, 2017

Key Takeaways

  • In a group of patients undergoing radial access, 15.4% developed acute kidney injury (AKI) after percutaneous coronary intervention (PCI) compared with 17.4% in the femoral access group.

Randomized clinical trials demonstrating the effectiveness of radial access (RA) on improved outcomes following percutaneous coronary intervention (PCI) have increased interventionalists’ utilization of RA.1,2 Despite the available evidence which supports the efficacy of RA, whether or not this approach influences the risk of acute kidney injury (AKI) is uncertain.

The Impact of Radial vs Femoral Access on AKI

In approximately 7% of cases, AKI occurs following a PCI and is associated with high mortality.3 There is speculation as to whether AKI and subsequent mortality represent a causal relationship, or if AKI is merely an indicator of an underlying issue.

The amount of contrast media used during a procedure predicts risk; however, there are numerous factors associated with AKI’s pathogenesis. Debate exists as to whether RA or femoral arterial access catheterization should be performed in patients at risk for AKI.

The Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox (MATRIX) trial was a randomized clinical trial comparing femoral and radial access for PCI and coronary angiography in patients with acute coronary syndrome (n = 8404).1 The risk for all-cause mortality was significantly lower in the radial access group (relative risk [RR]: 0.72; 95% confidence interval [CI]: 0.53 to 0.99; P =.045).

A subanalysis of the MATRIX trial, AKI-MATRIX, was designed to evaluate the effect of radial access vs femoral access on post-PCI AKI.4 In the group undergoing radial access, 15.4% developed AKI compared with 17.4% in the femoral access group (odds ratio [OR]: 0.87; 95% CI: 0.77 to 0.98; P =.018).

The lower incidence of bleeding events in the RA group may partly explain the mechanism behind the protective benefit of RA against AKI. Also, the operators in the MATRIX trial had greater RA expertise, which may have played a role. In addition, the analysis showed significant differences between patients referred to trans-radial PCI and trans-femoral PCI in baseline characteristics. Patients receiving trans-femoral PCI were older and had a higher number of comorbidities, and these patients also had a longer hospital stay. Research comparing a balanced patient demographic may provide more revealing answers to the radial vs femoral debate.

In contrast, a single-center, retrospective study by Flaherty et al suggested a protective benefit with Impella® device use in patients undergoing trans-femoral high-risk PCI.5 Patients in this study had an average left ventricular ejection fraction (LVEF) of ≤35%. Due to their low LVEF values, these patients were considered to be at high risk for AKI incidence. In addition to low LVEF, supported patients also had greater comorbidities at baseline than unsupported patients. Despite the greater baseline hazard, there was an observed, notable protective benefit associated with the Impella device.

In summary, the subanalysis of the MATRIX trial by Andò et al shows the radial approach to correlate with a lower risk for AKI compared with femoral, whereas Flaherty et al show that support with the Impella device during trans-femoral PCI procedures may be an effective strategy for reducing AKI incidence and providing a greater absolute risk reduction. Whether there is an additive benefit for radial PCI and Impella support in patients at risk for AKI is not yet known.


  1. Valgimigli M, Gagnor A, Calabró P, et al. Radial versus femoral access in patients with acute coronary syndromes undergoing invasive management: a randomised multicentre trial. Lancet. 2015;385(9986):2465-2476.
  2. Jolly SS, Yusuf S, Cairns J, et al. Radial versus femoral access for coronary angiography and intervention in patients with acute coronary syndromes (RIVAL): a randomised, parallel group, multicentre trial. Lancet. 2011;377(9775):1409-1420.
  3. Tsai TT, Patel UD, Chang TI, et al. Contemporary incidence, predictors, and outcomes of acute kidney injury in patients undergoing percutaneous coronary interventions: insights from the NCDR Cath-PCI registry. JACC Cardiovasc Interv. 2014;7(1):1-9.
  4. Andò G, Cortese B, Russo F, et al. Acute Kidney Injury After Radial or Femoral Access for Invasive Acute Coronary Syndrome Management: AKI-MATRIX. J Am Coll Cardiol [published online May 11, 2017]. doi: 10.1016/j.jacc.2017.02.070.
  5. Flaherty MP, Pant S, Patel SV, et al. Hemodynamic Support With a Microaxial Percutaneous Left Ventricular Assist Device (Impella) Protects Against Acute Kidney Injury in Patients Undergoing High-Risk Percutaneous Coronary Intervention. Circ Res. 2017;120(4):692-700.


Impella® Device — Indication & Safety Information



High-Risk PCI

The Impella 2.5®, Impella CP® and Impella CP® with SmartAssist® Systems are temporary (≤ 6 hours) ventricular support devices indicated for use during high-risk percutaneous coronary interventions (PCI) performed in elective or urgent, hemodynamically stable patients with severe coronary artery disease, when a heart team, including a cardiac surgeon, has determined high-risk PCI is the appropriate therapeutic option. Use of the Impella 2.5, Impella CP, and Impella CP with SmartAssist Systems in these patients may prevent hemodynamic instability, which can result from repeat episodes of reversible myocardial ischemia that occur during planned temporary coronary occlusions and may reduce peri- and post-procedural adverse events.

Cardiogenic Shock

The Impella 2.5®, Impella CP®, Impella CP® with SmartAssist®, Impella 5.0® and Impella LD® Catheters, in conjunction with the Automated Impella® Controller (collectively, "Impella® System Therapy"), are temporary ventricular support devices intended for short term use (≤ 4 days for the Impella 2.5, Impella CP, and the Impella CP with SmartAssist, and ≤ 14 days for the Impella 5.0, and Impella LD) and indicated for the treatment of ongoing cardiogenic shock that occurs immediately (< 48 hours) following acute myocardial infarction or open heart surgery or in the setting of cardiomyopathy, including peripartum cardiomyopathy, or myocarditis as a result of isolated left ventricular failure that is not responsive to optimal medical management and conventional treatment measures (including volume loading and use of pressors and inotropes, with or without IABP). The intent of Impella System Therapy is to reduce ventricular work and to provide the circulatory support necessary to allow heart recovery and early assessment of residual myocardial function.


Important Risk Information for Impella devices


The Impella 2.5, Impella CP, Impella 5.0 and Impella LD are contraindicated for use with patients experiencing any of the following conditions: Mural thrombus in the left ventricle; Presence of a mechanical aortic valve or heart constrictive device; Aortic valve stenosis/calcification (equivalent to an orifice area of 0.6 cm2 or less); Moderate to severe aortic insufficiency (echocardiographic assessment graded as ≥ +2); Severe peripheral arterial disease precluding placement of the Impella System; Significant right heart failure*; Combined cardiorespiratory failure*; Presence of an Atrial or Ventricular Septal Defect (including post-infarct VSD)*; Left ventricular rupture*; Cardiac tamponade*

* This condition is a contraindication for the cardiogenic shock indication only.


Acute renal dysfunction, Aortic valve injury, Bleeding, Cardiogenic shock, Cerebral vascular accident/Stroke, Death, Hemolysis, Limb ischemia, Myocardial infarction, Renal failure, Thrombocytopenia and Vascular injury

In addition to the risks above, there are other WARNINGS and PRECAUTIONS associated with Impella devices. Visit http://www.abiomed.com/important-safety-information to learn more.


Impella Connect®

The Impella Connect® transfers the video image of the screen on the Automated Impella® Controller to an authorized remote user. The transmitted image can be viewed by authorized remote users. The users can include the hospital’s clinicians, Abiomed local support staff, and Customer Support Center (CSC) team members.

Impella Connect Precautions

  • Impella Connect is not intended to provide real-time information for monitoring patient status on the Automated Impella® Controller.
  • During use of the Impella Connect, there will be a delay between when an image appears on the controller screen and when it is displayed at a remote viewing location.
  • The Impella Connect is not a source of patient alarms, nor is its use intended as a replacement for monitoring the controller’s alarms.
  • During use of the Impella Connect, receipt of the displayed controller information is not confirmed by the Automated Impella® Controller, nor is the delivery of the displayed controller information to the authorized remote users guaranteed.
  • The Impella Connect is not designed for use during transport.
  • Radiated and conducted electromagnetic interference can affect the performance of the Impella Connect, causing a temporary loss of connectivity. To clear interference, either increase the distance between system components and the EMI source or turn off the EMI source. Any electromagnetic interference related to the Impella Connect will have no impact on any of the controller functional specifications.
  • Portable and mobile RF communications equipment can affect medical electrical equipment.

Right-Side Support – Indication & Safety Info.


The Impella RP® System is indicated for providing temporary right ventricular support for up to 14 days in patients with a body surface area ≥1.5 m2, who develop acute right heart failure or decompensation following left ventricular assist device implantation, myocardial infarction, heart transplant, or open-heart surgery.

Important Risk Information for Impella RP


The Impella RP System is contraindicated for patients with the following conditions: Disorders of the pulmonary artery wall that would preclude placement or correct positioning of the Impella RP device. Mechanical valves, severe valvular stenosis or valvular regurgitation of the tricuspid or pulmonary valve. Mural thrombus of the right atrium or vena cava. Anatomic conditions precluding insertion of the pump. Presence of a vena cava filter or caval interruption device, unless there is clear access from the femoral vein to the right atrium that is large enough to accommodate a 22 Fr catheter.


The potential adverse effects (eg, complications) associated with the use of the Impella RP System: Arrhythmia, Atrial fibrillation, Bleeding, Cardiac tamponade, Cardiogenic shock, Death, Device malfunction, Hemolysis, Hepatic failure, Insertion site infection, Perforation, Phlegmasia cerulea dolens (a severe form of deep venous thrombosis), Pulmonary valve insufficiency, Respiratory dysfunction, Sepsis, Thrombocytopenia, Thrombotic vascular (non-central nervous system) complication, Tricuspid valve injury, Vascular injury, Venous thrombosis, Ventricular fibrillation and/or tachycardia.

In addition to the risks above, there are other WARNINGS and PRECAUTIONS associated with Impella RP®. Visit http://www.abiomed.com/impella/impella-rp to learn more.

General Indication and Safety Information

To learn more about the Impella platform of heart pumps, including important risk and safety information associated with the use of the devices, please visit: www.protectedpci.com/indications-use-safety-information/

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