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Hypertension, also known as high blood pressure, affects one in every three adults in the U.S.[1] Initial treatment for it should include healthy lifestyle changes, including weight and stress reduction, a healthy low-sodium diet and regular exercise.[2],[3] But when these fail, blood pressure medications become necessary.
Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are two effective classes of medications commonly used to lower blood...
Hypertension, also known as high blood pressure, affects one in every three adults in the U.S.[1] Initial treatment for it should include healthy lifestyle changes, including weight and stress reduction, a healthy low-sodium diet and regular exercise.[2],[3] But when these fail, blood pressure medications become necessary.
Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are two effective classes of medications commonly used to lower blood pressure (see table, below, for examples of products containing these medications). Some of these medications also are used to treat heart failure, cardiovascular disease and chronic kidney disease.
But what about taking these medications immediately before or after surgery?
On the one hand, combining general anesthesia with ACE inhibitors or ARBs[4] can result in dangerously low blood pressure levels.[5] That is why some doctors may ask patients to discontinue these medications at least 24 hours before surgery.[6]
On the other hand, taking these medications (or other hypertension drugs) is critical to controlling blood pressure and preventing the long-term and potentially fatal complications of uncontrolled hypertension, such as heart attack, stroke, heart failure and kidney disease.
How soon after surgery should patients resume these medications, and what are the risks associated with delaying their resumption?
Two recent studies[7],[8] used nationwide electronic medical record data from the Department of Veterans Affairs health care system — which has the largest integrated system in the U.S. — to address these questions.
Both of these studies show that delaying the resumption of ACE inhibitors or ARBs after surgery is common, and the studies link this delay to an increased risk of death within the first 30 days after surgery.
Examples of Available ACE Inhibitors and ARBs
| ACE inhibitors |
|---|
|
| ARBs |
|
*Limited Use
**Do Not Use
***Do Not Use for Seven Years (until at least March 2018)
The ACE inhibitors study
The ACE inhibitors study was published in the May 2014 issue of the Journal of Hospital Medicine[9]. Researchers examined data from over 240,000 patients who were taking an ACE inhibitor before undergoing major surgery during the period from 1999 to 2012.
The study found that 25 percent of these patients had not resumed their ACE inhibitors within the first 14 days after surgery. It also found that patients who did not resume these drugs had more than triple the risk of death in the first 30 days after surgery, compared with those who restarted treatment within the first 14 days.
This strong association between not resuming ACE inhibitors and an increased risk of death after surgery was consistent among patients who did not develop major complications after surgery as well as patients who survived the first two days after surgery.
The study results suggested that certain patient factors (such as male sex and heart failure) may further elevate death risks among patients who do not resume their ACE inhibitors within the first two weeks after surgery.
The ARBs study
The other study was published in the journal Anesthesiology in August 2015.[10] Researchers analyzed the medical records of 30,000 patients who were taking ARBs prior to undergoing noncardiac surgery during the period from 1999 to 2011.
The analysis showed that about 34 percent of the patients did not restart their ARB medications within the first two days after surgery, and 20 percent did not restart these medications by their 30th day after surgery.
After taking into account differences in patient characteristics and existing medical conditions before surgery, the study found that patients who did not restart their ARB treatment within the first two days after surgery had about a 50 percent higher risk of death within 30 days than those who resumed therapy within the first two days. The increased risk of death also was seen with those patients who did not resume treatment within one, seven and 14 days after surgery.
Additionally, the study showed that patients who did not resume their ARB medications by the second day after surgery developed slightly more complications (including heart failure, kidney failure and certain serious infections) than those who restarted their medications within this period.
Conclusions
Despite the two studies’ strength of using a large nationwide dataset, it is hard to establish a definitive, cause-and-effect relationship between not resuming blood pressure medications and death — only randomized clinical trials can do so.
However, the strong associations observed in these studies suggest that getting patients with hypertension back on their ACE inhibitors or ARBs within the first few days after surgery may reduce their risk of death and other complications.
Neither study was designed to determine how the failure to promptly resume these medications can increase death risk after surgery. However, previous studies show that withdrawing blood pressure medications such as ACE inhibitors can cause a rapid increase in blood pressure within 48 hours — which is particularly dangerous for patients with heart failure and coronary artery disease. Failure to restart these medications also may compromise kidney function.
What You Can Do
If you will be undergoing surgery and are taking an ACE inhibitor, an ARB or another blood pressure medication, you should talk with your surgeon about resuming these medications as soon as possible after surgery. Note that your surgeon may choose to withhold these medications for a few more days after surgery if you experience blood loss, dehydration or other complications, because such conditions can cause abnormally low blood pressure.
References
[1] Centers for Disease Control and Prevention. High blood pressure facts. February 2015. http://www.cdc.gov/bloodpressure/facts.htm. Accessed October 15, 2015.
[2] Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: The JNC 7 report. JAMA. 2003;289(19):2560-2571.
[3] James PA, Oparil S, Carter BL, et al. 2014 evidence-based guideline for the management of high blood pressure in adults: Report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311(5):507-520.
[4] Lee SM, Takemoto S, Wallace AW. Association between withholding angiotensin receptor blockers in the early postoperative period and 30-day mortality. Anesthesiology. 2015;123(2):288-306.
[5] Ibid.
[6] Bertrand M, Godet G, Meersschaert K, et al. Should the angiotensin II antagonists be discontinued before surgery? Anesthesia and Analgesia. 2001;92:26-30.
[7] Lee SM, Takemoto S, Wallace AW. Association between withholding angiotensin receptor blockers in the early postoperative period and 30-day mortality. Anesthesiology. 2015;123(2):288-306.
[8] Mudumbai SC, Takemoto S, Cason BA., et al. Thirty-day mortality risk associated with the postoperative nonresumption of angiotensin-converting enzyme inhibitors: A retrospective study of the Veterans Affairs Healthcare System. Journal of Hospital Medicine. 2014;9(5):289-296.
[9] Ibid.
[10] Lee SM, Takemoto S, Wallace AW. Association between withholding angiotensin receptor blockers in the early postoperative period and 30-day mortality. Anesthesiology. 2015;123(2):288-306.
