Cardiac Evaluation

The specific incidence and risk factors for major cardiac complications (cardiovascular death and nonfatal myocardial infarction) after meningioma resection are uncertain. The widely utilized Revised Cardiac Risk Index identifies ischemic disease, congestive heart failure, diabetes, cerebrovascular disease, and chronic kidney disease as risk factors for cardiac complications.3 Poor functional capacity, as evidenced by the inability to walk at least two blocks, also predicts a higher rate of cardiac complications. Recently revised guidelines for perioperative cardiac evaluations in noncardiac operations recommend delaying elective surgery in patients with unstable coronary artery disease, decompensated heart failure, severe arrhythmias, or severe valvular disease until their cardiac condition has been evaluated and treated.4 These guidelines recommend noninvasive stress testing for patients with active cardiac conditions, but there is no evidence that stress testing is required for patients undergoing intermediate risk procedures, such as craniotomy. Similarly, there is no evidence to support prophylactic coronary revascularization in surgical patients. In fact, patients with recently placed coronary artery stents are at very high risk of cardiac complications if their anti-platelet agents are stopped prematurely.

Pulmonary Evaluation

The American College of Physicians (ACP) has published guidelines and systematic reviews regarding the assessment and prevention of perioperative pulmonary complications.5–7 The major predictors of pulmonary complications are the type of procedure and the patient’s age. Neurosurgical procedures have been shown to increase the risk of postoperative pulmonary complications, such as mortality, prolonged intubation or reintubation, and pneumonia, with an odds ratio of 2.53.6 Of note, prolonged surgery time, defined as >2.5 to 4 hours, also increases the risk of postoperative pulmonary complications with an odds ratio of 2.26. Complicated meningioma resection cases commonly last beyond that time frame. Other risk factors related to pulmonary complications include history of chronic obstructive pulmonary disease or congestive heart failure, patients who are functionally dependent, and patients whose American Society of Anesthesiologists classification is ≥2.6. Surprisingly, obesity and well-controlled asthma have not been shown to be significant risk factors. In addition to history, abnormal findings on lung auscultation predict postoperative pulmonary complications.8 On the other hand, preoperative pulmonary studies such as chest radiography and pulmonary function testing are generally not useful.8 The ACP only recommends preoperative chest radiographs in patients with cardiopulmonary disease, age >50 years, or those undergoing abdominal or thoracic surgery.

Useful interventions to reduce pulmonary complications include preoperative respiratory training and postoperative lung expansion procedures, including incentive spirometry and positive pressure therapies.7 In addition, preoperative smoking cessation has been demonstrated to reduce wound-related complications in orthopedic surgery patients when undertaken at least 6 to 8 weeks before surgery.7

Laboratory Workup

The use of routine laboratory studies, including complete blood count, coagulation studies, and electrolytes, as a preoperative evaluation tool is controversial. They are costly to the health care system, and there is evidence that their use may not reduce postoperative complications.1 The American Society of Anesthesiologists issued a practice advisory in 2002 that does not recommend routine preoperative laboratory studies but instead recommends their selective use based on individual patients and the planned procedure.9 Intracranial procedures such as meningioma resections have unique risks, including bleeding, that likely warrant the use of routine laboratory studies.

Endocrine Workup

Meningiomas of the suprasellar or hypothalamic region also warrant an endocrinology evaluation to assess for hormone abnormalities related to pituitary stalk effect or hypothalamic compression. Workup should include evaluation of thyroid function (thyroid-stimulating hormone [TSH] and free T4), growth hormone function (somatomedin-c), serum prolactin, random or morning cortisol level, and possibly testosterone function if clinically indicated. Identification of hypothalamic-pituitary-axis abnormalities can help determine whether hormonal replacement therapies are needed (including perioperative stress-dose steroids) and provide documentation if abnormalities exist postoperatively. In addition, an ophthalmology assessment, including formal visual field testing, should be considered for suprasellar lesions. Although confrontation visual field examinations will detect gross visual field defects, alterations in light threshold responsiveness can only be done with modern ophthalmologic equipment. A computerized Humphrey visual field evaluation is recommended as a baseline before surgery for meningiomas in locations around the visual pathways, including the me-dial third sphenoid wing, clinoid, tuberculum, diaphragma sella, tentorium, and falx. This evaluation should be repeated 3 months postoperatively.

Preoperative Beta-Blockade

Much controversy exists regarding the benefit of perioperative β-blockade. Large randomized trials have shown that prophylactic use of β-blockers can prevent postoperative cardiac complications in higher-risk patients. However, overly aggressive use of these medications increases the risk of stroke and all-cause mortality.10,11 With regard to most neurosurgical operations, guidelines recommend continuing β-blockers in patients already taking them to treat cardiac disease such as angina, hypertension, or arrhythmia.4 They may be cautiously started in patients with more than one Revised Cardiac Risk Index predictor.

Anticoagulation

Many patients will be on chronic anticoagulation for thromboembolic prophylaxis in the setting of arterial stents, mechanical heart valves, atrial fibrillation, or a history of arterial or venous thromboembolic disease. Unfortunately, there are few data to provide guidance regarding the perioperative management of anticoagulation in patients undergoing intracranial or intraspinal procedures, such as meningioma resections. A 2008 guideline recommends stopping warfarin 5 days and antiplatelet therapies (aspirin or clopidogrel) 7 to 10 days before a surgical procedure.12 They also suggest bridging during the perioperative period with low molecular weight heparin or ultrafractionated heparin. These should be stopped 24 hours before the scheduled operation. For high bleeding risk procedures, they recommend restarting bridging therapy 48 to 72 hours postoperatively or when hemostasis has been obtained, or withholding bridging therapy altogether.12 The use of both pre- and postoperative anticoagulation has not been shown to affect postoperative intracranial hemorrhage in meningioma patients.13,14 Patients at very high thromboembolic risk, such as those with mechanical mitral valves or recent thromboembolism, may benefit from bridging with parenteral anticoagulants. The relative risk of thromboembolism and hemorrhage should be discussed with the patient’s medical specialists to determine whether a strategy of bridging is justified.

Preoperative Seizure Prophylaxis

Antiepileptic medication should naturally be continued during the perioperative period in patients with a known history of seizures. For meningioma patients with no history of seizures, however, a meta-analysis of five randomized controlled trials in patients with primary brain neoplasms found no effect of prophylactic antiepileptic medication on seizure control.15 The American Academy of Neurology does not recommend the use of antiepileptic medications in brain tumor patients with no history of seizures.16

Other Preoperative Medication Considerations

Although beyond the scope of this review, there are other comorbidities and medications that must be considered before surgical resection of a meningioma. Poorly controlled diabetic patients are at risk of infectious complications and higher mortality rates. In addition, use of oral hypoglycemics can lead to several adverse effects in the perioperative period, including hypoglycemia, and should be stopped preoperatively. Glycemic control should be managed with insulin intraoperatively and during the immediate postoperative period. Patients on chronic steroid therapy should also be assessed and the use of stress-dose steroids considered perioperatively.