The current practice of perioperative antiplatelet therapy also differs widely between institutions. The early use of aspirin is adopted by the majority of surgeons for OPCAB patients. Some institutions prefer to use clopidogrel in addition to aspirin especially for patients with complex sclerotic or narrow coronary or anastomosed grafts and previous percutaneous coronary intervention (PCI) using drug-eluting stents. Furthermore, warfarin is administered by the majority of surgeons controlling INR at around 2.0, when vein grafts are selected for coronary revascularization. This approach may be justified, as platelet dysfunction caused by CPB is obviously absent in OPCAB patients. Very few surgeons administer clopidogrel before surgery on the day of the OPCAB procedure.

Clopidogrel exposure prior to on-pump CABG is well known to increase the risk of postoperative bleeding, the need for perioperative transfusion, and the incidence of re-exploration. Conversely, clopidogrel administration following on-pump CABG is superior to aspirin in the end point of myocardial infarction, stroke, or graft patency [11]. In addition, most recent data demonstrate that early postoperative administration of clopidogrel is safe after OPCAB [12].

To date, no Japanese survey regarding strategical anticoagulation management during OPCAB has been performed, although Englberger et al. [13] conducted a European survey study to determine anticoagulation strategies in OPCAB using a questionnaire survey among 750 European cardiothoracic surgeons. A total of 325 (43.7 %) questionnaires were returned and analyzed. Perioperative protocols for administration of antiplatelets differed among the respondent surgeons, similar to those among surgeons in Japan. Intraoperative heparin dosage ranged between 70 and 300 unit/kg, and 60 % of the respondents preferred a low-dose regimen (150 or 100 unit/kg). Correspondingly, the lowest ACT during surgery was accepted to be 200 s by 24 %, 250 s by 18 %, and 300 s by 26 % of the surgeons. Protamine was used by 91 % of the respondents, while 52 % performed a 1:1 reversal. Perioperative protocols for administration of antiplatelets also differed significantly among the surgeons. Oral aspirin was given after surgery in 76 % of OPCAB patients, but 30 % of them started from the preoperative period. Clopidogrel was selected in 15 % of patients, and in half of them, clopidogrel was added to aspirin administration.

Atrial fibrillation (AF) is one of the most common complications after OPCAB and is associated with an increased risk of stroke and longer hospital stay. Hosokawa et al. [14] retrospectively reviewed 296 consecutive patients who underwent OPCAB. The incidence of AF was 32 % of all patients. In order to examine the predictors of AF after OPCAB, a stepwise multivariate analysis was performed demonstrating increasing age (odds ratio 1.44 per 10-year increase; 95 % confidence interval 1.06–1.95), intraoperative core body temperature (odds ratio 1.64; 95 % confidence interval 1.05–2.56), average cardiac index in the ICU (odds ratio 0.37; 95 % confidence interval 0.19–0.71), and intraoperative fluid balance (odds ratio 0.96 per 100-ml increase; 95 % confidence interval 0.93–0.99) as independent predictors for the development of AF.

In order to prevent AF after OPCAB, several trials and studies were performed in Japan focusing on the efficacy of perioperative beta-blocker administration. Fujii et al. [15] conducted a randomized prospective trial to determine the efficacy of intravenous landiolol administration in the early period after OPCAB followed by treatment with carvedilol for prevention of AF. Seventy consecutive patients were enrolled in the study. Patients in the treatment group received landiolol intravenously (5 μg/kg/min) in the ICU immediately after surgery until oral carvedilol was administered. All patients received oral carvedilol (2.5 mg–5 mg/day) after extubation, and this treatment was continued even after discharge. Postoperative AF occurred in 4 (11.1 %) of the 36 patients in the landiolol group and in 11 (32.3 %) of the 34 patients in the control group, indicating that development of AF was significantly inhibited by landiolol treatment (p = 0.042).

Wakamatsu et al. [16] reported that intraoperative low-dose infusion of landiolol hydrochloride (4.7+/−4.3 microgram/kg/min) decreased the incidence of postoperative AF from 37.8 to 18.6 % after OPCAB. In that study, no side effects, such as profound hypotension or bradycardia, were noticed during the infusion of landiolol hydrochloride.

Beside oral tablet administration with beta-blocking action, anti-arrhythmic drugs and preoperative statin preparation were emerging as promising treatments to prevent AF. Ito et al. [17] assessed the efficacy of treatment with the anti-arrhythmic drug propafenone hydrochloride, which was administered in the early postoperative period. Seventy-eight patients undergoing isolated OPCAB were divided into 2 groups: a propafenone hydrochloride group (P Group) and a control group (C Group). The patients in the P Group were given propafenone hydrochloride (150–450 mg/day orally) for 10 days from the day of surgery. The incidence of AF was 35 % in the C Group and 12 % in the P Group (p = 0.0337). Multiple logistic regression analysis showed that propafenone hydrochloride was the sole factor that prevented the development of AF after OPCAB (odds ratio 0.207; 95 % confidence interval 0.053–0.804; p = 0.0229).

Kinoshita et al. [18] assessed the preventive effect of preoperative statin treatment on the development of AF after elective isolated OPCAB. Among 584 patients, 364 received statin at least 5 days before surgery while 220 patients received no statin. They identified 195 propensity score-matched pairs. AF occurred in 14.4 % of patients in the statin group and in 24.6 % of patients in the no-statin group (p = 0.01). Multivariate logistic regression, including potential univariate predictors, identified statin treatment (odds ratio 0.49; 95 % confidence interval 0.22–0.81; p = 0.01), age (odds ratio 1.33 per 10-year increase; 95 % confidence interval 1.04–1.69; p = 0.02), and transfusion (odds ratio 2.21; 95 % confidence interval 1.38–3.55; p = 0.01) as independent predictors of postoperative AF.