Examkin

Question

Difficulty: MediumSurgical and Procedural Interventions

A 6262-year-old woman is evaluated in the preoperative clinic prior to an elective right hemicolectomy for colon cancer scheduled in one week. Her medical history is significant for a mechanical mitral valve replacement performed 55 years ago, paroxysmal atrial fibrillation, and essential hypertension. Her current medications include warfarin, metoprolol, and lisinopril. She reports excellent medication compliance and denies any recent dyspnea, orthopnea, chest pain, or palpitations. Her vital signs are within normal limits. Physical examination shows a well-healed median sternotomy scar and a crisp mechanical heart valve click without murmurs. Her lungs are clear to auscultation. Recent laboratory results show an International Normalized Ratio (INR) of 3.23.2. Which of the following perioperative management steps are indicated for this patient? (Select all that apply.)

  1. Discontinuation of warfarin 55 days prior to surgeryAnswer
  2. Initiation of therapeutic-dose low-molecular-weight heparin bridging 33 days prior to surgeryAnswer
  3. C
    Continuation of warfarin without interruption through the perioperative period
  4. D
    Routine preoperative transthoracic echocardiography
  5. E
    Administration of prothrombin complex concentrate on the morning of surgery

Answer

The correct interventions are the discontinuation of warfarin 5 days prior to surgery and the initiation of therapeutic-dose low-molecular-weight heparin (LMWH) bridging 3 days prior to surgery.
For elective procedures with high bleeding risk, warfarin must be withheld for approximately 5 days to allow the INR to normalize. Because this patient has a mechanical mitral valve, she is at high risk for valve thrombosis and systemic embolization. Therefore, she requires bridging therapy with a short-acting anticoagulant, such as therapeutic-dose low-molecular-weight heparin (LMWH), starting approximately 3 days prior to surgery (when the INR begins to fall below the therapeutic range). LMWH is then typically stopped 24 hours prior to the operation.

Step-by-Step Solution

1
Assess the patient's bleeding risk associated with the scheduled surgery.
A right hemicolectomy is a major intra-abdominal procedure with a high bleeding risk.
High bleeding risk procedures require normalization of coagulation status prior to the operation to prevent catastrophic hemorrhage.
2
Evaluate the patient's thromboembolic risk to determine the need for bridging anticoagulation.
The patient has a mechanical mitral valve, which confers a high risk for arterial thromboembolism.
Patients with high thromboembolic risk (e.g., mechanical mitral valve, older mechanical aortic valves, recent stroke) require bridging therapy with a short-acting anticoagulant when warfarin is withheld.
3
Formulate a timeline for holding warfarin and initiating bridging therapy.
Warfarin should be stopped 5 days before surgery. LMWH bridging should start 3 days before surgery.
This timeline ensures that the INR falls to a safe level (less than 1.5) for surgery while minimizing the time the patient is unprotected against thromboembolism.

Key Concept

Patients at high risk for thromboembolism, such as those with a mechanical mitral valve, require bridging anticoagulation with therapeutic low-molecular-weight heparin or unfractionated heparin when warfarin is interrupted for procedures with a high bleeding risk.
Rate this question

Topics

Surgical and Procedural Interventions

More questions from this topic