Clin. Cardiol. 15,709-710 (1992)
Editor’s Note Aspirin and Elective Surgical Procedures Recently, an 84-year-old female who was about to undergo elective surgery for squamous cell cancer of the vulva was transferred to our coronary care unit because of recurrent chest pain. The admitting diagnosis was “unstable angina.” As usual, the patient was treated with one aspirin, heparin, nitrates, and beta blockers, and, as usual, responded quite nicely. She never evolved a myocardial infarction. I thought the patient was now ready for GYN surgery, but the gynecologist wanted to postpone the surgery one week because of the single aspirin the patient was given. He was obviously concerned about the risk of bleeding. The patient was obviously upset at the delay. So was I! Several general points need to be considered about this situation. First, most people in the United States take aspirin. Second, most people who take aspirin don’t bleed excessively. Third, many patients undergo surgery. Fourth, it is not known how many patients who undergo surgery have taken an aspirin just prior to the surgery. Fifth, it is not known what the bleeding complication rate is with and without aspirin in the overwhelming majority of patients undergoing surgery. Sixth, if indeed aspirin increases the complication rate in some patients what can be done to identify the patient at high risk for bleeding? Last, if a “high risk” patient is identified, when should aspirin be stopped prior to surgery? Any standard textbook of pharmacology states that aspirin therapy alters platelet function within a few hours of oral administration and will prolong bleeding times for at least seven days. What does this mean to the clinician whose patient is scheduled for elective surgery, but has taken an aspirin the day before? I did a Med-Line search on this subject and came up with a few articles I would like to share (in abbreviated form) with the reader. It was not easy to find articles about aspirin and noncardiac surgical procedures. I found one. An and colleagues report on 140 patients who underwent total hip arthroplasty.’ They analyzed intraoperative and postoperative blood loss and found that patients who had received aspirin or nonsteroidal anti-inflammatory drugs prior to surgery experienced increased intraoperative and postoperative blood loss compared with the patients who did not take such medications. Taggart et al., in a cohort study of 202 patients undergoing elective coronary bypass surgery, found that regular daily lowdose aspirin therapy (75 mg/day) produces significant increases in postoperative blood loss, resulting in a substantial increase in blood transfusion and hemostatic pack requirements, but does not prolong postoperative hospital stay.*They recommend discontinuing aspirin one week before operation. In a letter to the editor related to the Taggart article, Violaris and Angelini analyzed the data in a different manner.3They point out that there is no obvious intergroup difference, as the median and interquartile ranges overlap to such a great extent, and the confidence intervals indicate that there was no statistical difference in postoperative blood loss and transfusion. Thus, one must question the recommendation that aspirin therapy should be discontinued one week before operation. Taggart et al. basically agreed that statistical significance was not reached, probably because of the small number of patients in each of the individual aspirin groups and the relatively wide-scattered data.“ An interesting study was reported by Rawitscher et u Z . , ~ who prospectively evaluated the effect of aspirin on red blood cell loss and blood transfusions in 100 consecutive patients with normal bleeding times undergoing elective coronary artery bypass surgery. Patients were taking 85-325 mg of aspirin daily up to within 48 hours of surgery and were compared with patients not taking aspirin, and with those who had discontinued aspirin at least four days before surgery. The results indicated that there were no significant differences between groups when red blood cell loss or transfusion requirements were assessed. They conclude that it is not necessary to delay elective coronary bypass surgery for the purpose of discontinuing aspirin.
Clin. Cardiol. Vol. 15, October 1992
In contrast, Bashein et al. performed a case control study to estimate the relative risk of re-operation from bleeding in coronary artery bypass graft patients who had taken aspirin within the seven days preceding surgery.6Their results indicated that aspirin exposure within 7 days before coronary bypass surgery is associated with an increased rate of re-operation for bleeding and that re-operation is associated with large increases in transfusion requirements and intensive care unit and hospital stays. Bartley and Warndahl state in a letter to the editor that a single, small dose of aspirin may increase the bleeding time of a normal person for 4-7 days, presumably because of decreased formation of the platelet aggregation stimulator thromboxane Az7 They recommend that if medically appropriate, the patient should discontinue taking any medications that contain aspirin at least one week before a planned surgical procedure. How should the physician interpret these data? Certainly, no one wants excessive bleeding intraoperatively or postoperatively for any of his patients. The requirement for a blood transfusion in 1992 is a small but definite risk. The development of hematomas in the wound certainly increases the risk of infection, slow healing, prolonged hospitalization,and so forth. I don’t think there is any doubt that aspirin alters platelet function. The real question is whether it really makes any clinical difference in the majority of patients undergoing all sorts of surgical procedures. My guess is that it doesn’t. However, no large scale trial has been done to provide us with guidelines. I think Rawitscher et al. performed the best study (i.e., it was randomized and prospective), and they could show no difference in patients given aspirin who had normal bleeding times. The key point here is the normal bleeding time. At present, I believe it is sound and reasonable practice to send patients to surgery who have received aspirin, but whose bleeding time is normal. Therefore, I obtain a bleeding time in any of my patients who are on aspirin and who require elective surgery. If the bleeding time is excessively prolonged, I would agree that surgery should wait until bleeding time returns to the normal range, unless the circumstances demand immediate surgery. If the bleeding time is prolonged, the odds of a major complication occurring are still low.
References An HS, Mikhail WE, Jackson WT, Tolin B, Dodd GA: Effects of hypotensive anesthesia, nonsteroidal antiinflammatory drugs, and polymethylmethacrylate on bleeding in total hip arthroplasty patients. J Arihroplusty 199,6(3), 245-250 (1991) 2. Taggart DP, Siddiqui A, Wheatley DJ: Low-dose preoperative aspirin therapy, postoperative blood loss, and transfusion requirements.Ann Thoruc Surg 5 0 , 4 2 5 4 2 8 (1990) 3. Violaris AG, Angelini GD: Aspirin and blood loss (letter).Ann Thoruc Surg 51,693-697 (1991) 4. Taggart DP, Wheatley DJ: (letter). Ann Thoruc Surg 51,693-697 (1991) 5. Rawitscher RE, Jones JW,McCoy TA, Lindsley DA: A prospective study of aspirin’s effect on red blood cell loss in cardiac surgery. J Curdiovusc Surg 32(1), 1-7 (1991) 6. Bashein G, Neely ML, Rice AL.,Counts RB, Misbach GA: Preoperative aspirin therapy and reoperation for bleeding after coronary artery bypass surgery. Arch InternMed 151 (l), 89-93 (1991) 7. Bartley BB, Warndahl RA:Surgical bleeding associated with aspirin and nonsteroidal anti-inflammatory agents (letter). Muyo Clin Prnc 67(4), 4 0 2 4 0 3 (1992) 1.