A case of myocardial infarction caused by obstruction of a drug-eluting stent during the perioperative period

2014 ACC/AHA guideline recommend that, for patients who require PCI but are scheduled for elective non-cardiac surgery in the subsequent 12 months, balloon angioplasty or BMS implantation followed by 4 to 6 weeks of DAPT are reasonable strategies [1]. For patients with DES who must undergo urgent surgical procedures that mandate the discontinuation of DAPT, however, it is reasonable to continue aspirin if possible and restart the P2Y12 inhibitor as soon as possible in the immediate postoperative period [1, 2]. And the study showed that incidence of major adverse cardiac event (MACE) was significantly higher (10–15 %) during the first 30 days after the stent implantation [3]. In our case, placement of a DES was the primary issue for the patient, who urgently required tracheostomy because of airway narrowing. The discontinuation of antiplatelet therapy shortly after the myocardial infarction and DES placement induced the SAT, which was the secondary issue.

Bridging with anticoagulants, such as low-molecular-weight heparin, after interruption of DAPT during the perioperative period is advised [2]. In Japan, unfractionated heparin, having no evidence and used empirically, is also advised [4]. But the newer perioperative guideline recommend continue DAPT in patients undergoing urgent noncardiac surgery during the first 4 to 6 weeks after BMS or DES implantation unless the risk of bleeding outweights the benefit of stent thrombosis prevention [1]. In addition, there has not been any evidence demonstrating the efficacy of bridging with anticoagulants using heparin. In this case, we performed anticoagulation therapy using unfractionated heparin. Nevertheless, the serum CK-MB value of the patient was elevated at the time of cessation of heparin despite a slightly prolonged aPTT (Table 1). The all surgical staffs failed to share the elevated serum CK and CK-MB values at that point and failed to cancel the surgery, which were the third issue. And a white thrombus in the DES was confirmed at the time of recanalization. Although his preoperative aPTT was not markedly prolonged, anticoagulant therapy of 400 U/h of unfractionated heparin could not have prevented platelet thrombosis in this case.

It has been reported that the cumulative incidences of bleeding 30 days after surgical procedures were significantly higher in patients with DAPT than in patients with single or no antiplatelet therapy [5]. In this case, the first surgery was performed after discontinuation of both antiplatelet and anticoagulation therapy. Therefore, surgical hemostasis was easily obtained and not strictly performed, and bleeding only became obvious after restarting heparin and DAPT. If the surgery was performed under continuous DAPT, however, similar or massive bleeding might have occurred in the perioperative period. Because the patient had been placed a DES, we should have first performed the tracheostomy on the patient with strict hemostasis to secure the airway under continuation of DAPT or only aspirin a month after the DES implantation. Then, six months after the DES implantation, we should have performed the laryngectomy and right hemi-thyroidectomy [1].

Because the patient might have mild impairment in expression of chest pain due to progressive laryngeal cancer and/or feel little pain due to nerve damage by old myocardial infarction, the patient could complained less chest pain at the time of visiting to local hospital and entering the operation room, which could induced misjudgment. And a series of human errors occurred and caused life-threatening complications. Human errors were as follows: the cardiologist at the local hospital chosen DES instead of BMS or POBA regardless of scheduled total larygectomy; the root cause of this incident, the discontinuation of antiplatelet therapy shortly after the myocardial infarction and DES placement, and the all surgical staffs failed to share the elevated serum CK and CK-MB values and failed to cancel the surgery. After this case, we proposed to create the hospital task force for updating and promoting the perioperative PCI, antiplatelet and anticoagulation procedures. This task force consisted of the representatives from departments of all surgery, anesthesiology, cardiology, gastroenterology, pharmacy and hospital medical safety management office. Then, this task force announced the updated those procedures in our hospital. And now we are exploring a method of enhancing the detection of laboratory test abnormality shortly before the surgery.

Because the patient had airway stenosis with a recent placement of DES, we should have first performed the tracheostomy on the patient with strict hemostasis to secure the airway under continuation of DAPT or only aspirin a month after the DES implantation. Then, six months after the DES implantation, we should have performed the laryngectomy and right hemi-thyroidectomy. This case is serious warnings of perioperative MACE induced by discontinuation of DAPT; 400 U/h of unfractionated heparin was an insufficient safeguard against platelet thrombosis, and perioperative massive bleeding then induced by restarting antiplatelet and anticoagulation therapy. In addition, a series of human errors, which the cardiologist at local hospital chosen DES regardless of scheduled total larygectomy, the discontinuation of antiplatelet therapy, and the surgical staffs failed to share the elevated serum CK and CK-MB values, caused life-threatening complications. Anesthesiologists should promote the information about the perioperative risks and managements of PCI and DAPT to surgeons and cardiologists further widely.

Written informed consent was obtained from the patient for publication of this Case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.