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Perioperative cardiovascular medicine: 5 questions for 2018

Cleveland Clinic Journal of Medicine. 2018 November;85(11):853-859 | 10.3949/ccjm.85a.18066
November 1, 2018|Cleveland Clinic Journal of Medicine
Kunjam Modha, MD, FACP;Kay M. Johnson, MD, MPH;Ethan Kuperman, MD, FHM;Paul J. Grant, MD, SFHM, FACP;Barbara Slawski, MD, MS, SFHM;Kurt Pfeifer, MD, FACP, SFHM;Steven L. Cohn, MD, FACP, SFHM
Author and Disclosure Information

Kunjam Modha, MD, FACP
Assistant Professor of Medicine, Cleveland Clinic Lerner College of Medicine and Case Western Reserve University, Cleveland, OH; Director, Medicine Consultation Service, Cleveland Clinic

Kay M. Johnson, MD, MPH
Associate Professor, Division of General Internal Medicine, University of Washington School of Medicine, Seattle; Hospital and Specialty Medicine, VA Puget Sound Healthcare System, Seattle, WA

Ethan Kuperman, MD, FHM
Clinical Assistant Professor, Division of General Internal Medicine, Department of Internal Medicine, University of Iowa, Iowa City

Paul J. Grant, MD, SFHM, FACP
Associate Professor of Medicine, Associate Chief Medical Information Officer, and Director, Perioperative and Consultative Medicine, Division of Hospital Medicine, Department of Internal Medicine,
University of Michigan, Ann Arbor

Barbara Slawski, MD, MS, SFHM
Professor of Medicine and Orthopedic Surgery; Chief, Section of Perioperative and Consultative Medicine, Division of General Internal Medicine, Department of Medicine, Medical College of Wisconsin, Milwaukee

Kurt Pfeifer, MD, FACP, SFHM
Professor of Medicine, General Internal Medicine, Medical College of Wisconsin, Milwaukee

Steven L. Cohn, MD, FACP, SFHM
Professor Emeritus, Director, Medical Consultation Service, Jackson Memorial Hospital, University of Miami Miller School of Medicine, Miami, FL

Address: Kunjam Modha, MD, FACP,  Department of Hospital Medicine, M2 Annex, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; modhak@ccf.org

ABSTRACT

A MEDLINE search was performed from January 2017 to February 2018, and articles were selected for this update based on their significant influence on the practice of perioperative cardiovascular medicine.

KEY POINTS

  • Patients undergoing noncardiac surgery who have a history of percutaneous coronary intervention will benefit from continuing aspirin perioperatively if they are not at very high risk of bleeding.
  • Myocardial injury after noncardiac surgery is strongly associated with a risk of death, and the higher the troponin level, the higher the risk. Measuring troponin T before and after surgery may be beneficial in patients at high risk if the information leads to a change in management.
  • Perioperative hypotension can lead to end-organ dysfunction postoperatively. There is conflicting evidence whether the absolute or relative reduction in blood pressure is more predictive.
  • Perioperative risk of stroke is higher in patients with patent foramen ovale than in those without.
  • Many patients who recently had a stroke suffer recurrent stroke and major adverse cardiac events if they undergo emergency surgery.

DOES PATENT FORAMEN OVALE INCREASE THE RISK OF STROKE?

Perioperative stroke is an uncommon, severe complication of noncardiac surgery. The pathophysiology has been better defined in cardiac than in noncardiac surgeries. In nonsurgical patients, patent foramen ovale (PFO) is associated with stroke, even in patients considered to be at low risk.13 Perioperative patients have additional risk for venous thromboembolism and may have periprocedural antithrombotic medications altered, increasing their risk of paradoxical embolism through the PFO.

[Ng PY, Ng AK, Subramaniam B, et al. Association of preoperatively diagnosed patent foramen ovale with perioperative ischemic stroke. JAMA 2018; 319(5):452–462.]

This retrospective cohort study of noncardiac surgery patients at 3 hospitals14 sought to determine the association of preoperatively diagnosed PFO with the risk of perioperative ischemic stroke identified by International Classification of Diseases diagnoses.

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Of 150,198 patients, 1.0% had a preoperative diagnosis of PFO, and at baseline, those with PFO had significantly more comorbidities than those without PFO. Stroke occurred in 3.2% of patients with PFO vs 0.5% of those without. Patients known to have a PFO were much more likely to have cardiovascular and thromboembolic risk factors for stroke. In the adjusted analysis, the absolute risk difference between groups was 0.4% (95% CI 0.2–0.6%), with an estimated perioperative stroke risk of 5.9 per 1,000 in patients with known patent foramen ovale and 2.2 per 1,000 in those without. A diagnosis of PFO was also associated with increased risk of large-vessel-territory stroke and more severe neurologic deficit.

Further attempts to adjust for baseline risk factors and other potential bias, including a propensity score-matched cohort analysis and an analysis limited to patients who had echocardiography performed in the same healthcare system, still showed a higher risk of perioperative stroke among patients with preoperatively detected patent foramen ovale.

Limitations. The study was retrospective and observational, used administrative data, and had a low rate of PFO diagnosis (1%), compared with about 25% in population-based studies.15 Indications for preoperative echocardiography are unknown. In addition, the study specifically examined preoperatively diagnosed PFO, rather than including those diagnosed in the postoperative period.

Discussion. How does this study affect clinical practice? The absolute stroke risk was increased by 0.4% in patients with PFO compared with those without. Although this is a relatively small increase, millions of patients undergo noncardiac surgery annually. The risks of therapeutic anticoagulation or PFO closure are likely too high in this context; however, clinicians may approach the perioperative management of antiplatelet agents and venous thromboembolism prophylaxis in patients with known PFO with additional caution.

HOW DOES TIMING OF EMERGENCY SURGERY AFTER PRIOR STROKE AFFECT OUTCOMES?

A history of stroke or transient ischemic attack is a known risk factor for perioperative vascular complications. A recent large cohort study demonstrated that a history of stroke within 9 months of elective surgery was associated with increased adverse outcomes.16 Little is known, however, of the perioperative risk in patients with a history of stroke who undergo emergency surgery.

[Christiansen MN, Andersson C, Gislason GH, et al. Risks of cardiovascular adverse events and death in patients with previous stroke undergoing emergency noncardiac, nonintracranial surgery: the importance of operative timing. Anesthesiology 2017; 127(1):9–19.]

In this study,17 all emergency noncardiac and nonintracranial surgeries from 2005 to 2011 were analyzed using multiple national patient registries in Denmark according to time elapsed between previous stroke and surgery. Primary outcomes were 30-day all-cause mortality and 30-day major adverse cardiac events (MACE), defined as nonfatal ischemic stroke, nonfatal myocardial infarction, and cardiovascular death. Statistical analysis to assess the risk of adverse outcomes included logistic regression models, spline analyses, and propensity-score matching.

Findings. The authors identified 146,694 emergency surgeries, with 7,861 patients (5.4%) having had a previous stroke (transient ischemic attacks and hemorrhagic strokes were not included). Rates of postoperative stroke were as follows:

  • 9.9% in patents with a history of ischemic stroke within 3 months of surgery
  • 2.8% in patients with a history of stroke 3 to 9 months before surgery
  • 0.3% in patients with no previous stroke.

The risk plateaued when the time between stroke and surgery exceeded 4 to 5 months.15

Interestingly, in patients who underwent emergency surgery within 14 days of stroke, the risk of MACE was significantly lower immediately after surgery (1–3 days after stroke) compared with surgery that took place 4 to 14 days after stroke. The authors hypothesized that because cerebral autoregulation does not become compromised until approximately 5 days after a stroke, the risk was lower 1 to 3 days after surgery and increased thereafter.

Limitations of this study included the possibility of residual confounding, given its retrospective design using administrative data, not accounting for preoperative antithrombotic and anticoagulation therapy, and lack of information regarding the etiology of recurrent stroke (eg, thromboembolic, atherothrombotic, hypoperfusion).

Conclusions. Although it would be impractical to postpone emergency surgery in a patient who recently had a stroke, this study shows that the incidence rates of postoperative recurrent stroke and MACE are high. Therefore, it is important that the patient and perioperative team be aware of the risk. Further research is needed to confirm these estimates of postoperative adverse events in more diverse patient populations.

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