A 78-year-old man, who is treated by calcium channel blockers for arterial hypertension (HTN), has just met an anesthesiologist before hip replacement. He has no diabetes, has never smoked, and used to be a runner. Because of hip arthritis, the patient’s activities are limited (barely walks, lives in a 1-floor house, does not do gardening anymore) and his wife is taking care of all the housekeeping. The patient reports a nocturnal dyspnea. The clinical examination revealed a blood pressure of 148/69 mm Hg, a heart rate of 72 beats/min, and no sign of cardiac failure. The blood chemistry reveals a normal renal function, hemoglobin levels are 14 g/dL, and brain natriuretic peptide (BNP) levels are 350 pg/mL. The anesthesiologist has advised the patient to consult a cardiologist.

This case demonstrates a situation where the anesthesiologist and cardiologist should work together, prior to surgery, to assess the status of a patient and discuss perioperative management. In fact, this patient is about to undergo a surgery that is associated with high risk of complications by major cardiac events, such as acute heart failure (HF). Although he has few cardiac risk factors, his functional activity is not assessable and nocturnal dyspnea associated with increased plasmatic BNP levels raises the suspicion of an unknown HF that must be explored. Hence, in this case, it is recommended to perform an electrocardiogram (ECG) and a transthoracic echocardiography (TTE). Additional tests, such as a stress testing, will be discussed depending on the results of the first exams. The persistent high blood pressure and the probable HF necessitate reassessing the patient’s current medical treatment and considering treatment by beta blockers, if the procedure can be postponed for 3 to 6 months.

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  HF is a complex clinical syndrome that can result from a variety of lesions of the myocardium, pericardium, heart valves, or great vessels as well as metabolic abnormalities, which leads to an impairment of ventricular relaxation, ejection, or both.¹

  
  
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  HF can be classified in 4 stages, from A (patients at high risk for HF, without symptoms of HF) to D (refractory HF).¹

  
  
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  The incidence of HF increases with age. As the population is aging, and the therapeutics of HF is improving, the number of HF patients keeps raising, with an estimated 50% increase in the number of new patients with HF every year in 15 years.²

  
  
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  Concomitantly, the number of surgical procedures performed yearly is increasing, especially in the elderly, with more than one-third of the procedures being performed in patients who are age 65 years and older.³

  
  
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  Hence, HF is more and more often encountered in the perioperative settings.

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  Despite improvements in perioperative care, cardiac complications are the leading cause of postoperative deaths.

  
  
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  Because HF is a significant risk for perioperative morbidity and mortality, it is a component of indices that predict the risk of perioperative major cardiovascular events (MACE). MACE is defined as death from a cardiovascular cause or nonfatal myocardial infarction. The revised cardiac risk index (RCRI), which contains 6 items, is the oldest and most easily validated risk predictor (Table 43-1). Having at least 2 RCRI items classifies a patient as high risk for perioperative MACE.^4,5

  
  
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  HF is a well-established perioperative risk factor. Among patients age 65 years and older who undergo major noncardiac surgery, the perioperative mortality rate is at least doubled if they have HF. From the Medicare 5% standard analytic files, Hammill and colleagues retrospectively studied 159,327 procedures (including 13 types of major noncardiac surgery) in patients age 65 years and older. After adjustment for type of procedure, demographics, and comorbidities, patients with HF had a 63% higher mortality and a 51% higher 30-day readmission rate than patients without HF or with coronary artery disease.⁶ In addition, HF was an independent risk factor for mortality, in almost all types of major noncardiac procedures (Figure 43-1).

  
  
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  Among patients who have HF, those who have a more severely impaired ejection fraction (EF) have a worse outcome. In patients with HF who had a high-risk noncardiac surgical procedure, Healy and colleagues reported that severely reduced EF (<30%), but not moderately (30%-40%) or mildly (40%-50%) impaired EF was associated with more adverse perioperative events including myocardial infarction, HF exacerbation, and mortality within 30 days after surgery (Figure 43-2).⁷ In this population, the 3 independent risk factors of adverse perioperative events were an age above 80 years, an EF below 30%, and diabetes.⁷

  
  
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  Even in the absence of HF symptoms, isolated diastolic left ventricular (LV) dysfunction and systolic LV dysfunction are associated with increased morbidity (30-day cardiovascular events) and long-term cardiovascular mortality.⁸

  
  
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  Taken together, these data suggest that prior to a major surgical procedure, patients with HF should be closely evaluated to assess their HF state. Moreover, it seems necessary to detect patients who have an asymptomatic impairment of the LV function.

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  During surgical procedures, injured tissues develop neuroendocrine responses. This surgical stress leads to an inflammatory state with an increase of oxygen consumption, a fluid shift, and a disruption of the balance between prothrombotic and fibrinolytic factors, the latter favoring thrombosis. Moreover, surgical stimulation activates the renin-angiotensin-aldosterone system (RAAS). Surgical factors that are associated with an increase in cardiac events are urgency, type, invasiveness, and duration of the procedure.

  
  
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  During general anesthesia, anesthetic agents may impair hemodynamics via direct effects on the myocardium and the vessels, and via indirect effects through the central inhibition of the sympathetic system. The most common agents used are volatile anesthetics, propofol and morphinomimetics. Volatile anesthetics induce a dose-dependent decrease in arterial blood pressure (through a decrease in systemic vascular resistances), inhibit the baroreceptor arc, and alter the contractility as well as the relaxation of both ventricles. Propofol lowers sympathetic nerve activity and blood pressure. Morphinomimetics do not alter the cardiac function.

  
  
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  General anesthesia requires mechanical ventilation. It induces an increase in intrathoracic pressure leading to a decrease of venous return and eventually cardiac output, which is more marked in cases of hypovolemia. Increased intrathoracic pressure deteriorates right ventricular (RV) function, particularly in cases of high pulmonary arterial pressure. In contrast, increased intrathoracic pressure lowers transmural pressure, which decreases the LV afterload and favors LV function.

  
  
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  The magnitude of the cardiovascular effects of general anesthesia depends on the pre existing cardiovascular state of the patient. Greater effects will be observed if patients have altered systolic function of any ventricles, which will be more sensitive to a decrease of the contractility and variations of the cardiac load. In addition, long-term treatments, such as RAAS inhibitors, increase the risk of perioperative hypotension.

  
  
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  Finally, depending on the surgery, general anesthesia is associated with a certain degree of fluid loss, anemia, and hypothermia, which may increase perioperative morbidity.

  
  
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  Postoperative time is also a sensitive period. Factors such as withdrawal of anesthetic drugs, awakening, extubation, pain, hypothermia, and anemia contribute to activate the sympathetic system, and increase oxygen consumption. Moreover, because patients are unable to take oral drugs during the postoperative time after procedures such as major gastrointestinal tract surgery, the withdrawal of HF drugs can increase the risk of arrhythmia, HTN, and acute HF.

  
  
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  Taken together, surgery and anesthesia induce hemodynamic stress, fluid variations, and metabolic stress that could be compared to a stressing exercise for the myocardium and can lead to acute HF, myocardial ischemia, and death (Figure 43-3).

  
  
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  The latest guidelines on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery propose to separate the surgical procedures into 2 categories.⁴ During a low-risk procedure, the combined surgical and patient characteristics predict a risk of MACE <1%. Elevated-risk surgeries are associated with a MACE ≥1% (Table 43-2).