Radial Approach Promising in STEMI Patients with Cardiogenic Shock

The radial approach is safe and feasible in patients with ST-segment elevation myocardial infarction (STEMI) and cardiogenic shock, a population traditionally excluded from many investigational trials. In a study published online February 1, 2013, ahead of print in the American Heart Journal, transradial primary percutaneous coronary intervention (PCI) offered a mortality advantage at 1 year compared with the femoral approach.

Researchers led by Olivier F. Bertrand, MD, PhD, of Laval University (Quebec City, Canada), evaluated outcomes of 197 STEMI patients with signs of cardiogenic shock who were treated with primary PCI between 2006 and 2010 at 2 high-volume centers in Canada and the Czech Republic. The radial approach was used successfully in 55% of cases where at least 1 radial artery was weakly palpable.

Radial Linked to Greater Survival

Use of intraaortic balloon pump (IABP) therapy was required in 2 patients who underwent radial PCI and presented with femoral bleeding. Taking into account IABP therapy, the rate of non-access site bleeding or hemoglobin drop without overt bleeding represented a majority of the total bleeding in the radial (79%) and femoral (64%) groups. Transfusion rates were high and similar in both arms as well (19% vs. 22%, P = 0.52).

At 1 year, mortality was lower in the radial group compared with the femoral group (44% vs. 64%; P = 0.0044). Patients who died were an average of 5 years older and less often treated by the radial approach. They also were more likely to have hypertension, chronic kidney disease, multivessel disease, and poor final epicardial flow (table 1).

Table 1. Comparison of Survivors vs. Non-survivors

The radial approach emerged as an independent predictor of survival, as did glycoprotein IIb/IIIa inhibitor (GPI) use. Baseline creatinine ≥ 110 μmol/L, initial glycemia > 200 mg/dL, and age > 65 years, meanwhile, were predictors of mortality (table 2).

Table 2. Independent Predictors of 1-year Mortality

New Therapeutic Strategies Still Needed

According to the study authors, the data represent the first time that radial access has been identified as an independent predictor of mortality in STEMI patients presenting with cardiogenic shock.

“Our multivariate model seems to have good predictability and accuracy,” Dr. Bertrand and colleagues write. “Given the poor outcomes of those patients, further new therapeutic strategies remain, however, to be defined.”

They acknowledge that due to the observational nature of the study, selection bias and unmeasured confounding factors may have influenced the findings. Additionally, details about inotropic therapies were not collected and varied among operators. Also, since the study population included only those with early shock (before primary PCI and < 12 hours after symptom onset), applicability of the findings to different patient populations with later presentation remains unknown.

Making the Case for Radial

“It is frequently claimed that you cannot perform radial PCI for complex lesions or when the patient is very unstable,” Dr. Bertrand said in an e-mail communication with TCTMD. “We simply wanted to show that in 2 large-volume, experienced centers with both approaches (radial and femoral) we still were using radial when [it] was feasible. In fact, radial access may let the operator focus on the coronary intervention while the groin arteries (right or left) remain accessible [in case] hemodynamic (balloon pump or LVAD) support is emergently required during the procedure or if a [pacemaker] needs to be placed rapidly.”

He noted that in practice, the study authors use radial access in more than 95% of their cases. Therefore, in that context, a 55%  rate of radial access in shock patients is far less than the norm and is due to the lack of radial pulse or the operator wishing to proceed more rapidly and therefore choosing femoral access instead.

“The ultimate challenge is that when patients presenting in shock have no radial pulse it is practically impossible to puncture the radial artery,” he said. “Hence maybe further techniques should be tested to improve the rates of radial success (for example echo-guided radial puncture).” In the study, a noradrenaline drip was used in some cases to raise blood pressure and secure radial access, Dr. Bertrand noted.

While less bleeding, fewer vascular complications and accelerated hemostasis are all known benefits of radial access, Dr. Bertrand said there may be other benefits as well for patients with cardiogenic shock.

He also noted that in the recent IABP-SHOCK II trial, use of IABP therapy did not significantly reduce 30-day mortality in patients with cardiogenic shock although it has become a common strategy (Thiele H. NEJM 2012;Epub ahead of print). According to Dr. Bertrand, clinicians should take note that increased use of radial access and less routine use of IABP therapy in the femoral artery may further reduce bleeding in this population, reserving femoral access only for cases where IABP, LVAD or pacemaker are determined to be required, or in case of complications.

Study Details

Overall, 45% of patients had single-vessel disease, 30% had 2-vessel disease, and 25% had 3-vessel disease. Patients in the radial group had a lower incidence of diabetes compared with the femoral group (13% vs. 26%; P = 0.028), and were less likely to require intubation (42% vs. 66%; P = 0.0006) or IABP therapy (36% vs. 55%; P = 0.0096).

 

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Source:
Bernat I, Abdelaal E, Plourde G, et al. Early and late outcomes after primary percutaneous coronary intervention by radial or femoral approach in patients presenting in acute ST-elevation myocardial infarction and cardiogenic shock. Am Heart J. 2013;Epub ahead of print.

 

 

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