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Interrupt Antiplatelet Therapy Only Briefly in Stented Patients

Publish date: March 11, 2011
Author(s):
M. Alexander Otto

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Prospective Randomized Studies are Lacking

The proper timing of discontinuation of anticoagulants perioperatively is a nebulous question; concerns about warfarin are still not well answered, and with the increasing use of endovascular coronary and peripheral interventions, the use of antiplatelet agents also poses concerns.

No prospective randomized studies exist evaluating the outcomes with continuation or discontinuation of antiplatelet agents perioperatively. Discontinuing Plavix for 3 days preoperatively, as recommended by Dr. Dardik, is unlikely to significantly decrease bleeding, because Plavix irreversibly modifies platelet receptors, and reversal of effect is dependent on platelet turnover, which typically occurs in 5 to 7 days, not 3 days. The need to discontinue anticoagulants also does depend on the extent of surgical dissection. Recent studies have shown the safety of continued use of antiplatelet agents in peripheral vascular and cerebrovascular procedures. However, major intra-abdominal, retroperitoneal, or thoracic procedures may pose a higher risk for bleeding because of the extent of tissue dissection and inability to compress the area.

I agree that postponing elective surgery for 6 months to 1 year, with discontinuation of antiplatelet therapy, is the most prudent choice for major elective procedures. For urgent procedures, a team assessment is needed, including the cardiologist, surgeon, and possibly vascular surgeon or hematologist to determine the risk of bleeding vs. the risk of thrombosis for a given patient. Surgeons must consider the risk of thrombosis as much as the risk of bleeding in deciding whether to withhold antiplatelet therapy in those with recent endovascular interventions.

Dr. Linda Harris is vice chair, faculty development, department of surgery, Millard Fillmore Gates Hospital-Kaleida, Buffalo, N.Y.


 

FROM THE ANNUAL ACADEMIC SURGICAL CONGRESS

HUNTINGTON BEACH, CALIF. – Patients with recently placed coronary stents who are on clopidogrel to prevent stent thrombosis may need to discontinue the drug to prevent excessive bleeding during surgery, but it should be restarted as soon as possible, according to Dr. Alan Dardik.

Continuing antiplatelet therapy during the perioperative period is crucial, he noted, because "the risk of surgical bleeding, if dual-antiplatelet therapy is continued, is actually lower than the risk of coronary thrombosis due to agent withdrawal" (Intern. Emerg. Med. 2009;4:279-88).

Antiplatelet drugs pose a considerable bleeding risk: Aspirin can increase surgical blood loss up to 20%, and dual therapy up to 50%. According to Dr. Dardik, however, although "many studies show a small increase in complications from this bleeding, particularly increased transfusions, no study has actually shown an increase in mortality."

Meanwhile, the risk of a fatal myocardial infarction is high when antiplatelet therapy is withdrawn, especially within 6 weeks of stent placement. The risk is especially high in patients with cancer, diabetes, and other hypercoagulable states, and in those with long, multiple, or overlapping stents, Dr. Dardik said (Circulation 2007;116:745-54).

"Keep the nontherapeutic window short, from about 3 days before the surgery to 1 to 2 days afterwards, [and] reload [patients] at high risk for thrombosis with 300 mg of clopidogrel," Dr. Dardik said at the annual Academic Surgical Congress.

Since dual-antiplatelet therapy is standard for 6 months following stent placement, patients on clopidogrel (Plavix) will almost certainly also be on aspirin. To offset the temporary loss of clopidogrel, he recommended increasing the aspirin dose. If patients must come off aspirin, too, "reintroduce [it] the day after surgery," said Dr. Dardik, a vascular surgeon at Yale University, New Haven, Conn.

The best option for recently stented patients is to postpone surgery for at least 6 months – the point at which dual-antiplatelet therapy can be discontinued – or even a year, when aspirin can also be stopped.

When that’s not possible, Dr. Dardik recommends performing a less invasive procedure, with easier hemostasis.

In addition, "work with your [general practitioner], your cardiologist, and your anesthesiologist to evaluate the risk of bleeding versus thrombosis," Dr. Dardik said.

If it is known that a patient who is planned for a stent will need surgery within a year, he also suggested considering whether angioplasty alone or some other therapeutic intervention might be appropriate.

At this point, bare-metal and drug-eluting stents appear to carry similar thrombosis risks, Dr. Dardik noted.

He said he has no relevant disclosures.

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