The literature has numerous studies examining the effect of timing of surgery after MI and coronary stenting and MACE (major adverse cardiovascular events). However, for stroke, data is sparse.
Now comes a study from Denmark, published in JAMA. In Denmark, all medical data is collected (single payer), allowing retrospective databases studies to be done on complete, reliable datasets. The disadvantage is that it is an ethnically uniform database, which the authors correctly say potentially limits the generalizability of the results. They looked at “Danish nationwide cohort study (2005-2011) including all patients aged 20 years or older undergoing elective noncardiac surgeries (n=481 183 surgeries)”; 7137 had had prior stroke.
What I found fascinating is that a key part of their data was a nationwide Anesthesia database:
Information on several surgery-related variables, including whether the surgery was acute or elective, was retrieved from the Danish Anesthesia Register, in which all surgeries requiring anesthesia have been registered since mid-2004.
So, what did they find?
In summary, we demonstrated that prior ischemic stroke, irrespective of time between ischemic stroke and surgery, was associated with an adjusted 1.8- and 4.8-fold increased relative risk of 30-day mortality and 30-day MACE, respectively, compared with patients without prior stroke. Second, we demonstrated a strong time-dependent relationship between prior stroke and adverse postoperative outcome, with patients experiencing a stroke less than 3 months prior to surgery at particularly high risk. The risk stabilized after approximately 9 months. Third, the increased relative risks associated with prior stroke were found to be of at least similar magnitudes in low- and intermediate-risk surgeries, as in high-risk surgeries.
Red arrows show the particularly high odds ratios of MACE, death, and new stroke when surgery is performed < 3 months after prior CVA.
Elective surgery in the first 3 months is associated with much higher MACE rates. These rates stabilize by 9 months s/p CVA.
The authors did multiple analyses to try to limit the confounding effect that early surgery after stroke might indicate a not-elective indication for surgery. For example, they looked at the association of time after stroke and total knee or hip replacement (without fracture – presumably elective), and found similar elevated rates of MACE in the first 3 months.
There is possible room for improvement, since only 52% of prior CVA patients were chronically on statins, and only 65% on antiplatelet meds (such as aspirin and/or plavix) before surgery. Indeed, when adjusted for comorbidities, they found that in patients with prior CVA, chronic statins and antiplatelets meds were associated with reductions in postop MACE, including death from any cause.
What are some take away points?
- Elective surgery should probably wait until 9 months after prior stroke.
- This is probably true for low risk and intermediate risk surgeries, not just major ones.
- These results likely do not apply to CEA or carotid stenting, where the goal is to repair the source of arterial occlusion and/or thromboembolism