Platelet P2Y12 Receptor Inhibition and Perioperative Patient Management

P2Y12 receptor inhibitor use increases bleeding risk in surgical patients by inhibiting platelet aggregation. Preoperative monitoring, platelet transfusion, and targeted reversal strategies with novel therapies may help to optimize patient management.

Perioperative Platelet Inhibition in Elective Inguinal Hernia Surgery—Increased Rate of Postoperative Bleeding and Hematomas?

In patients on oral antiplatelet therapy secondary to critical vascular diseases, the risk of interrupting antiplatelet therapy has to be weighed against the risk of postoperative hematoma or bleeding when surgery is planned. The goal of this study was to determine the risk of postoperative hematoma and postoperative bleeding in elective inguinal hernia surgery during continuous platelet inhibition. Patients receiving either elective total extraperitoneal hernioplasty or Lichtenstein repair for inguinal hernia were included. Patients with mere suture repair, emergency hernia repair, combination of different simultaneous operations, and patients under therapeutic anticoagulation with heparin were excluded. Postoperative bleeding/hematoma was determined by physical examination and graded according to the Clavien-Dindo classification. Between January 2006 and December 2013, 561 patients with elective surgical repair of an inguinal hernia were included. A total of 29 patients were under continuous perioperative platelet inhibition (PI) with either aspirin or clopidogrel in addition to perioperative antithrombotic prophylaxis with subcutaneous dalteparin injections (PI group). A total of 532 patients received perioperative antithrombotic prophylaxis only (control group). The number of patients under antiplatelet therapy increased from 1.3% (Jan. 2006–Dec. 2009) to 10.0% (Jan. 2010–Dec. 2013; P < 0.0001). Postoperative hematoma/bleeding occurred in 5 PI patients (17.2%) versus 38 control patients (7.1%, P = 0.062). Rate of postoperative bleeding or hematoma is not higher under mono antiplatelet therapy for elective inguinal hernia repair. Since the majority of hematomas can be treated conservatively, it seems unnecessary to stop mono platelet inhibition perioperatively.

Experience using pipeline embolization device with Shield Technology in a patient lacking a full postoperative dual antiplatelet therapy regimen

Utilization of flow diverting devices is accompanied with dual antiplatelet therapy to reduce the risk of thromboembolic events, even though this increases the risk of hemorrhagic complications. The updated Pipeline Flex embolization device with Shield Technology has been created using a phosphorylcholine coating that reduces thrombogenicity and possibly reduces the need for dual antiplatelet therapy. However, because of the potential risk to patients of utilizing a pipeline embolization device without dual antiplatelet therapy, the pipeline embolization device with Shield Technology has not been tested in human subjects without dual antiplatelet therapy, and its contribution to preventing thromboembolic events is therefore unknown. We report a case in which a patient, following complications that limited his absorption of dual antiplatelet therapy, had low levels of dual antiplatelet therapy medications in his bloodstream following treatment for an intracranial aneurysm with a pipeline embolization device with Shield Technology. The patient recovered without signs of luminal stenosis or thromboembolic event.

Dual antiplatelet therapy with aspirin and clopidogrel: what is the risk in noncardiac surgery? A narrative review

Clopidogrel is one of the most commonly prescribed medications and is currently recommended along with aspirin as treatment to be used for 1 year in all patients without contraindications following an acute coronary syndrome. Patients who are committed to clopidogrel therapy due to recent coronary artery stent implantation may require noncardiac surgery during this recommended period of dual antiplatelet therapy (DAPT). Due to differing rates of endothelialization, patients who undergo bare-metal stent implantation generally require ≥ 1 month of uninterrupted DAPT, and those who undergo drug-eluting stent implantation require ≥ 12 months. Many surgeons ask their patients to stop taking clopidogrel in advance of their procedure to decrease perioperative bleeding. This practice is based largely on anecdotal experience and extrapolated from limited data in cardiac surgery. Premature cessation of aspirin and/or clopidogrel following coronary artery stenting, however, has been associated with acute stent thrombosis, myocardial infarction, and death. We searched PubMed for English language articles published from 1960 to 2012, using the keywords aspirin, clopidogrel, surgery, general, vascular, genitourinary, thoracic, orthopedic, ophthalmologic, dermatologic, endoscopy, colonoscopy, cardiac device implantation, pacemaker, defibrillator, bronchoscopy, bridging, bleeding complications, and transfusion, including various combinations. s were reviewed to confirm relevance, and then the full articles were extracted. References from extracted articles were also reviewed for relevant articles. Literature regarding perioperative clopidogrel continuation is predominantly composed of small, nonrandomized data, but suggests that most noncardiac surgeries or procedures can be performed safely while patients are taking clopidogrel. In this article, we review the current best evidence on the risk for bleeding with clopidogrel therapy in noncardiac surgery, summarize recent guidelines on appropriate duration of DAPT, and make recommendations on the management of perioperative DAPT.

Preoperative thienopyridine use and outcomes after surgery: a systematic review

BACKGROUND

Although studies have demonstrated excess risk of ischemic events if aspirin is withheld preoperatively, it is unclear whether preoperative thienopyridine use influences postoperative outcomes.

METHODS

We conducted a systematic review of 37 studies (31 cardiac and 6 noncardiac surgery, 3 randomized, 34 observational) comparing postoperative outcomes in patients who were versus were not exposed to thienopyridine in the 5 days before surgery.

RESULTS

Exposure to thienopyridine in the 5 days preceding surgery (compared with no exposure) was not associated with any reduction in postoperative myocardial infarction (23 studies, 12,872 patients, 3.4% vs 3.0%, odds ratio [OR] 0.98; 95% confidence interval [CI], 0.72-1.34), but was associated with increased risks of stroke (16 studies, 10,265 patients, 1.9% vs 1.4%, OR 1.54; 95% CI, 1.08-2.20), reoperation for bleeding (32 studies, 19,423 patients, 4.3% vs 1.8%, OR 2.62; 95% CI, 1.96-3.49), and all-cause mortality (28 studies, 22,990 patients, 3.7% vs 2.6%, OR 1.38; 95% CI, 1.13-1.69). Results were identical when analyses were restricted to long-term users of thienopyridines who continued versus held the medication in the 5 days before surgery. Although all associations were similar in direction for the subset of patients undergoing noncardiac surgery, 97% of the outcome data in this meta-analysis came from cardiac surgery trials.

CONCLUSIONS

These data support withholding thienopyridines 5 days before cardiac surgery; there was insufficient evidence to make definitive recommendations for elective noncardiac surgery although the direction and magnitude of associations were similar.

Poly-N-acetyl glucosamine fibers accelerate hemostasis in patients treated with antiplatelet drugs

BACKGROUND

Nanofibers consisting of poly-N-acetyl glucosamine (pGlcNAc), as the functional component of products for surface hemostasis, have been shown to activate platelets and thereby the clotting mechanism. The nanofiber-activated platelets provide a catalytic surface for acceleration of the intrinsic coagulation cascade, thrombin generation, and fibrin polymerization.

METHODS

Thromboelastographic analysis was undertaken to study the role of the pGlcNAc nanofibers in platelet activation and acceleration of fibrin polymerization. Thromboelastographic studies were performed without added activators of coagulation.

RESULTS

The pGlcNAc nanofibers were found to accelerate fibrin polymerization in whole blood and platelet-rich plasma. Treatment with eptifibatide (an inhibitor of the platelet GPIIbIIIa receptor) and corn trypsin inhibitor inhibited clotting of whole blood and platelet-rich plasma. The inhibition was reversed by treatment with pGlcNAc nanofibers. Inhibition was not observed after treatment with aspirin alone, MRS2359 (platelet ADP receptor inhibitor), or by a combination of aspirin and MRS2359. The pGlcNAc nanofibers accelerate clotting in normal blood treated with aspirin and MRS2359. Clopidogrel (Plavix) and aspirin did not affect the kinetics of pGlcNAc-mediated fibrin polymerization in blood from patients treated with antiplatelet drugs compared with nontreated blood.

CONCLUSIONS

These results provide evidence that pGlcNAc nanofibers activate platelets and accelerate the clotting of blood, and on how best to achieve surface hemostasis when patients are coagulopathic because of shock and/or to treatment with antiplatelet drugs.

Assessing the risk of clopidogrel-related bleeding complications in patients undergoing inguinal herniorrhaphy

BACKGROUND

To date, no studies have investigated how the preoperative management of clopidogrel, an irreversible antiplatelet agent, influences the outcome following minor operative procedures. The purpose of this study is to determine if clopidogrel use within 7 days of inguinal herniorrhaphy increases the postoperative risk for bleeding-related morbidity or mortality.

METHODS

A retrospective chart review was performed of 46 patients on clopidogrel who underwent inguinal herniorrhaphy from 2004 to 2008. Patients were grouped based on the last administered dose of clopidogrel; <7 days (A) and ≥ 7 days (B).

RESULTS

Of the 46 patients, 20 were in group A and 26 were in group B. No significant differences in operative blood loss, perioperative transfusion requirement, postoperative bleeding complications, intensive care unit (ICU) requirements, mortality, or 30-day readmission/reoperation rates were demonstrated between patients in groups A and B. Patients in group A had a significantly increased postoperative admission rate (65% vs. 15%, P = 0.0002) and increased mean hospital stay (1.0 vs. 0.15 days, P = 0.003). However, urinary retention, pain management, and the monitoring of other conditions accounted for over 80% of these admissions. One patient in group A (5%) developed a postoperative hematoma, which is consistent with the complication rate seen in the general population after inguinal herniorrhaphy. Overall, no difference in admission secondary to hematoma or postoperative bleeding was demonstrated.

CONCLUSION

Clopidogrel use within 7 days of inguinal herniorrhaphy did not increase the risk for perioperative bleeding complications. No mortalities, readmissions, or ICU requirements occurred, regardless of the timing of clopidogrel cessation. The increased risk for hospital admission and length of stay seen in group A is likely to be attributable to nonbleeding-related patient factors rather than clopidogrel use. Thus, it may not be necessary to interrupt clopidogrel therapy prior to inguinal herniorrhaphy in high-risk patients.