**2. Outline for the chapter**


### **3. Bleeding reduction and impact on mortality**

Radial access found a niche initially by patient preference and potential benefit given the complications with femoral or brachial access [1]. Radial artery access for coronary angiography and percutaneous intervention is deemed safer than femoral access, positively impacting mortality, and bleeding risk.

A multicenter randomized controlled trial involving 8404 participants with acute coronary syndrome found that using radial access decreases major bleeding [RR 0.67 (0.49–0.92), p = 0.01] and all-cause mortality [RR 0.72 (0.53–0.99), p = 0.045] compared to femoral access [7]. The RIFLE-STECAS trial involved only patients with ST-elevation myocardial infarction (STEMI) (n = 1001), and found lower bleeding rates (7.8% vs. 12.2%, p = 0.026) and cardiac mortality in the radial access group (5.2% vs. 9.2%, p = 0.02), and decreased median length of stay [5 [4–7] days vs. 6 [5–8], p = 0.03] [8]. The RIVAL trial separately studied the outcomes of STEMI (n = 1958) and non-ST elevation acute coronary syndrome (n = 5063) patients. Survival benefit and decreased bleeding risk with radial access was seen in the STEMI group [9]. A comparative study of STEMI patients in cardiogenic shock after PCI (n = 2663) showed that 1-year mortality was lower using the transradial approach compared to transfemoral (44% vs. 64%, p = 0.004), with radial artery access being an independent predictor of 1-year mortality [HR 0.65 (0.42–0.98), p = 0.041] [10]. The rate of TIMI 3 flow was identical in both groups. Major bleeding was higher in the femoral group (25% vs. 13%, p = 0.04) as well as bleeding related to access site (9 vs. 0.9%, p = 0.01) [10]. The STEMI-RADIAL trial also involved STEMI patients (n = 707), and found decreased composite endpoint of death, myocardial infarction, stroke, major bleeding, and vascular complications (4.6% vs. 11%, p = 0.003) but similar mortality rates at 30 days (2.3% vs. 3.1%, p = 0.64) and 6 months (2.3% vs. 3.6%, p = 0.31) [11]. The SAFARI-STEMI trial enrolled 2292 out of 4800 patients, halted prematurely because of futility finding 30-day mortality was similar between the radial and femoral access groups (RR 1.15 (0.58–2.30), p = 0.69). There was no difference in bleeding risk [RR 0.71 (0.38–1.33), p = 0.28] [12]. These findings can be explained by the fact that the proceduralists were experienced cardiologists at high-volume centers, a closure device was used in 68% of patients in the femoral group, less 2b3a inhibitor was used and bivalirudin was favored in 92% of those patients, which is known to cause less bleeding than heparin [12].

Yet the totality of data from 12 randomized clinical trials over the past decade found particularly in those with acute coronary syndrome, a lower bleeding rate translated into lower mortality [3]. This prompted a radial first approach by the American Heart Association for those with acute coronary syndrome [3].
