17 Jul Stroke History Raises Risks of Non-Cardiac Surgery
Medical Research: What are the main findings of the study?
Answer: We included all patients undergoing non-cardiac surgery in 2005-2011, which were then categorized by time elapsed between stroke and surgery. Patients with a very recent stroke, i.e. less than 3 months prior to surgery, had a significant 14 times higher relative risk of 30-day MACE following surgery, compared with patients without prior stroke. Patients with a more distant stroke had a 2-5 fold higher risk of MACE following surgery, and still significantly higher than risks in patients without prior stroke.
An additional model including time between stroke and surgery as a continuous measure showed a steep decrease in risks of perioperative MACE during the first 9 months. After 9 months, an increase in time between stroke and surgery did not further reduce the risks. The results for 30-day all-cause mortality showed similar patterns, although estimates were not as dramatic as for 30-day MACE.
When analyzing the MACE components individually, we found that recurrent strokes were the main contributor to the high risk of MACE. A history of stroke any time prior to surgery was associated with a 16 fold increased relative risk of recurrent stroke, compared with patients without prior stroke.
We also performed analyses stratified by surgery risk as low- (OR for stroke anytime, 3.97; 95% CI, 2.79-5.66), intermediate- (OR for stroke anytime, 4.46; 95% CI, 2.87-5.13) and high-risk (OR for stroke anytime, 1.98; 95% CI, 1.20-3.27), which were somewhat challenged in power. However, results indicated that stroke associated relative risk was at least as high in low and intermediate-risk surgery as in high risk surgery.
Medical Research: Were any of the findings unexpected?
Answer: The analyses stratified by surgery risk showed that surgeries traditionally categorized as low-risk and intermediate-risk surgeries were demonstrated to be associated with at least the same relative risk of perioperative MACE as high-risk surgeries, were unexpected. Further, these analyses also showed that patients with a stroke less than 3 months prior to surgery were at particularly high risk of perioperative MACE, as seen in our main analyses.
Do to relatively small sample sizes in these analyses, findings do need to be confirmed, but the message that no surgery is small enough to be considered safe in this group of patients, is an important message of our study
Medical Research: What should clinicians and patients take away from your report?
Answer: We believe that our message of a markedly increased risk in patients with very recent strokes, and a steep decrease in risk towards 9-month may help guiding clinicians in the decision making process. Thus, our clear opinion is that the advantages of surgery in patients with a recent stroke must be balanced with the very high risks of perioperative adverse events and that each patient should be carefully considered and evaluated independently. Further, we must keep in mind that competing risks might weigh in and although these analyses were comprehensively adjusted and only elective surgeries were included, residual confounding is always a risk in these studies.
Medical Research: What recommendations do you have for future research as a result of this study?
Answer: At the moment, we believe that these results are the most complete and reliable ones available, and though they should be considered in the preparation of future perioperative guidelines.
Also, we would like to take the chance to encourage future prospective clinical trials evaluating the potential for optimizing the treatment of patients with a recent stroke, where postponing the surgery beyond the suggested 9 month limit, is not an option.
Time Elapsed After Ischemic Stroke and Risk of Adverse Cardiovascular Events and Mortality Following Elective Noncardiac Surgery
Mads E. Jørgensen MB, Christian Torp-Pedersen MD, DSc, Gunnar H. Gislason MD, PhD, Per Føge Jensen MD, PhD, MHM, Siv Mari Berger MB, Christine Benn Christiansen MD, Charlotte Overgaard MSc, PhD, Michelle D. Schmiegelow MD, Charlotte Andersson MD, PhD
JAMA. 2014;312(3):269-277. doi:10.1001/jama.2014.8165