What the Anesthesiologist Should Know before the Operative Procedure

Percutaneous valve repair and replacement procedures have proven as the treatment of choice in high risk and inoperable patients. These procedures are now being expanded to intermediate risk and are currently in trial in lower risk patients. The rapid advancement in the area of percutaneous valve replacement has lead to a decrease in mortality, vascular complications, and decreased incidence of paravalvular leak when compared previous generation valves.

Percutaneous valve procedures are routinely performed outside of the routine operating room (OR) in either a cardiac catheter laboratory or a hybrid OR setting with additional fluoroscopic capabilities that are similar to those of a cardiac catheter laboratory. Routinely, the anesthesiologist is confronted with limited space in an unfamiliar environment. In the event of emergent conversion of a transcatheter aortic valve implantation (TAVI) procedure to conventional surgery, cardiopulmonary bypass (CPB) should be readily available. It is important to discuss beforehand patients who are thought to be candidates for CPB and/or sternotomy should catastrophic complications occur.

Selected percutaneous approaches to specific valvular pathology include:
  • Balloon valvuloplasty for aortic valve stenosis (AS) or mitral valve stenosis (MS)


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  • Transcatheter aortic valve implantation (TAVI) for AS (either transfemoral or transapical approach), off-label use for AI

  • Edge-to-edge repair for mitral regurgitation (MR), primarily for leaflet prolapse

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Most percutaneous valve repair procedures are elective and require detailed planning and thorough preoperative evaluation of the patient.

Emergent- Percutaneous valve repair or replacement procedures are usually not performed emergently.

Urgent- Only under rare circumstance will a percutaneous valve repair such as a balloon valvuloplasty be performed urgently. Occasionally, due to increased symptoms, will a percutaneous mitral valve repair or TAVR be performed urgently.

Elective- Routinely, percutaneous approaches to valvular disease require a detailed preoperative evaluation of the patient thus making these procedures elective by default. In addition, most percutaneous valve procedures (such as TAVI) continue to be investigational which demands an elective enrollment.

2. Preoperative evaluation

A thorough preoperative evaluation with special emphasis on the following diagnostic tests and comorbidities should be performed:

  • Transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE) to assess valve areas, gradients, regurgitant flow, cardiac function and associated pathology

  • Angiography (cardiac cath) or CT angiography (aorta and access vessels)

  • Electrocardiogram to assess heart rhythm (e.g. normal sinus rhythm, atrial fibrillation, RBBB, or pacemaker)

  • Comorbidities (other cardiac disease, pulmonary, renal, neurologic, metabolic or orthopedic disease)

  • Airway assessment (intubation problems, morbid obesity, obstructive sleep apnea)

  • Medication and allergies

  • Past surgical history

    Medically unstable conditions warranting further evaluation include: acute coronary artery disease or myocardial infarction, infection, symptomatic arrhythmia, stroke, coma, acute respiratory failure, uncontrolled diabetes mellitus.

    Delaying surgery may be indicated if: preoperative therapy and/or optimization of the patient’s condition could improve overall outcome or if the above mentioned medically unstable conditions warrant immediate attention and treatment before the elective procedure can be considered.

3. What are the implications of co-existing disease on perioperative care?

b. Cardiovascular system

Coronary artery disease

  • Evaluation: history and physical exam, EKG, Holter monitor, TTE, stress-echocardiogram, dobutamine stress echocardiogram or myocardial perfusions scintigraphy

  • Goals of management: preoperative optimization with either therapeutic revascularization or initiation of medical treatment such as betablockade, statin or aspirin.

Congestive heart failure

  • Evaluation: history and physical exam, EKG, TTE as indicated, chest X-ray

  • Goals of management: medical optimization through resolution of heart failure symptoms not thought to be secondary to valvular heart disease.

Cardiac arrhythmias

  • Evaluation: history and physical exam, EKG, Holter monitor, 24-hour EKG, TTE

  • Goals of management: restoration of normal sinus rhythm if possible (e.g. cardioversion for atrial fibrillation).

c. Pulmonary

COPD

  • Evaluation: history and physical exam, chest X-ray, pulmonary function tests (ABG, FEV1, FVC, DLCO)

  • Goals of management: optimization of preoperative respiratory function through medical therapy (e.g. addition of bronchodilators in obstructive disease as determined by metacholine challenge or initiation of antibiotic therapy in case of concomitant pulmonary infection). Consider preoperative physical therapy (e.g., incentive spirometry). In case of obstructive sleep apnea ensure that patients brings home CPAP device to hospital so that CPAP can be initiated postoperatively.

Asthma

  • Evaluation: history and physical exam, chest X-ray, pulmonary function tests (ABG, FEV1, FVC, DLCO). The clinical history is essential, especially history of emergency room visits and/or intubations. Also look for a history of systemic steroid use.

  • Goals of management: optimization of preoperative respiratory function through initiation of bronchodilator therapy such inhaled corticosteroids, beta-agonists, leukotriene inhibitors etc.

d. Renal-GI:

Acute and chronic renal disease

  • Evaluation: History and physical exam, basic metabolic panel, creatinine clearance, renal ultrasound as indicated, especially in cases of acute renal dysfunction

  • Goals of management: immediate treatment of reversible causes of acute kidney injury, optimization of volume status in order to minimize risk of renal injury (possibly hydration or if indicated initiation of diuretic therapy).

e. Neurologic:

Cerebrovascular disease (acute and chronic)

  • Evaluation: History and physical exam, head CT or MRI in acute onset of symptoms to rule out embolic or hemorrhagic stroke. Ultrasound and Doppler of carotid arteries, EKG to assess heart rhythm, TEE as indicated to rule out embolic etiology, CT angiography to evaluate cerebrovasculature. Ensure thorough documentation of preoperative neurologic status.

  • Goals of management: immediate treatment of acute onset transient ischemic attack (TIA) or stroke, optimization of glucose levels, temperature, cerebral perfusion pressure (via hemodynamic monitoring), consider revascularization of carotid arteries or other cerebral vasculature as indicated (consider percutaneous approaches/stenting).

f. Endocrine:

Diabetes mellitus

  • Evaluation: History and physical exam, close review of patients records, distinction between type 1 and type 2 diabetes, laboratory tests as indicated including fasting glucose, hemoglobin A1C

  • Goals of management: glycemic control, determination of optimal perioperative insulin regimen and regimen for pre- and postoperative oral antidiabetic medications. Include endocrine team for management if available.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

Dental:

  • Evaluation: History and physical exam, dentist consultation

  • Goals of management: Restoration of dental hygiene and/or removal of decayed teeth prior to implantation of percutaneous hardware (e.g., artificial valve).

Infectious disease:

  • Evaluation: History and physical exam, MRSA screening, culture urine, blood, sputum, urine analysis

  • Goals of management: Therapy of active infection, e.g., urinary tract infection with short course antibiotics, isolation of carriers of acute infection

4. What are the patient's medications and how should they be managed in the perioperative period?

N/A

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

Anticoagulants such as anti-platelet agents or others (aspirin, clopidogrel, coumadin, heparin)

  • Patients on aspirin: current guidelines advocate preoperative withdrawal of aspirin only in strictly elective patients without coronary syndromes with the expectation that blood transfusion will be reduced (IIa recommendation, level of evidence A).

  • Patients on thienopyridines (such as clopidogrel): current guidelines consider it reasonable to discontinue thienopyridines 5 to 7 days prior to cardiac procedures to limit blood loss and transfusion (IIa recommendation, level for evidence B). Alternatively, patients can be transitioned to more short-acting anti-platelet agents

  • Patients on coumadin should be transitioned to perioperative heparin i.v.

i. What should be recommended with regard to continuation of medications taken chronically?

Comment: similar to other cardiac surgery procedures.

5. What laboratory tests should be obtained and has everything been reviewed?

N/A

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

General anesthesia continues to be the anesthetic management of choice but sedation and monitored anesthesia care (MAC) have increased in incidence for these procedures. High volume centers and experience with TAVR have significantly increased their percentage of MAC cases. Some advantages of general anesthesia (GA) are related to working conditions for the interventional cardiologist but GA also provides a secured airway and the possibility to monitor the procedure with TEE. This allows valve sizing, monitoring of cardiac function and assists the operator in positioning of a valve implant for AS or the assessment of post TAVR aortic insufficiency. Sedation with MAC has been shown to be a suitable alternative for TAVR as long as a qualified trained anesthesiologist is prepared to convert immediately to general anesthesia if required. Regardless of the anesthetic technique, because of the severe clinical condition of these patients, the presence of anesthesiologists with specific expertise in cardiac anesthesia continues to be essential for optimal peri- and postoperative care in collaboration with cardiologists and cardiovascular surgeons. For percutaneous mitral valve repair procedures, GA is typically necessary in order to perform procedural image guidance with TEE and to prevent patient mobility during critical portions of the procedure. Valvuloplasty procedures may be done under MAC or GA depending on stability of the patient and need for imaging with TEE.

a. Regional anesthesia – not indicated for these types of percutaneous procedures

b. General Anesthesia

  • Benefits include the secure airway, controlled ventilation, optimized working conditions for the interventional cardiologist/surgeon and the fact that the procedures can be closely monitored with TEE as complimentary imaging modality to fluoroscopy. TEE has been used with minimal and no contrast when concern for contrast nephropathy is extremely high.

  • Drawbacks include possible complications of a general anesthetic approach such as respiratory complications or postoperative confusion/delirium. This elderly and high-risk patient population may already suffer from preoperative cognitive dysfunction.

  • Other issues: current reviews and international experience with these percutaneous procedures suggest that regardless of the anesthetic technique, a cardiac anesthesia trained anesthesiologist should be directly involved in the anesthesia care.

  • Airway concerns: deep sedation in an elderly patient may result in silent aspiration while intubation for general anesthesia provides a secured airway.

c. Monitored Anesthesia Care

  • Benefits include the avoidance of possible side-effects of a general anesthetic. This may be of special importance in this elderly high-risk population.

  • Drawbacks include the fact that perioperative monitoring with TEE can not be performed. In addition, and depending on the experience of the interventional cardiologist who performs the procedure, there always is a chance that the anesthetic needs to be converted to a general anesthesia possibly under urgent or emergent conditions.

  • Other Issues: we recommend that a fully trained cardiac anesthesiologist is in charge of the anesthetic for all TAVI, valvuloplasty and edge-to-edge cases, regardless of the anesthetic approach. Patients should have and uncomplicated and fully accessible airway if MAC is selected and the patient should be alert and orientated at the beginning of the case. Contraindications for MAC include a difficult airway, significant obesity, obstructive sleep apnea, severe reflux or an impaired ability to communicate.

6. What is the author's preferred method of anesthesia technique and why?

At our institution, we have recently transitioned to doing nearly 75% of our TAVR cases under MAC. The attending anesthesiologist ultimately decides who is done under GA or MAC. In general, there appears to be less inotropic and vasopressor support along with quicker recovery times and shorter length of stay in appropriately chosen patients associated with sedation. Sedation is truly mild to moderate sedation by ASA definitions. The patients are arousable during the case and responsive to voice. The most important factor for success is patient understanding of the technique and their mental buy-in to the process. To ensure a successful procedure, all patients should be presented with the option of having the TAVR done under sedation versus GA at the time of their valve clinic and pre-anesthesia clinic visit.

Some considerations for GA include poor respiratory status, or inability to lie flat, excessive BMI, severe pulmonary HTN or right heart failure, need for TEE for procedure guidance or sizing and other concerns for decompensation or difficulty to transition to a general anesthetic.

Balloon valvuloplasty procedures for MS or AS are either performed under GA or done under sedation and MAC. All edge-to-edge mitral valve procedures are done under general anesthesia allowing for optimal conditions for TEE guidance of the procedure.

What prophylactic antibiotics should be administered? Routine surgical antibiotic prophylaxis such as Cefazolin or Cefuroxime with or without vancomycin are administered. If β-lactam allergy: Vancomycin, levofloxacin, or Clindamycin. Prophylactic antibiotics should be administered within 1 hour prior to skin incision according to SCIP guidelines.

What do I need to know about the surgical technique to optimize my anesthetic care? – For all TAVR cases it is important to know if the vascular access will be established via femoral, axillary, transcaval or transapical access routes. Further, it is important to know if periods of induced ventricular tachycardia are planned (e.g. during balloon valvuloplasty) and if a temporary pacing device will be placed preoperatively.

For all MV edge-to-edge procedures, vascular access will be established in the groin and the procedure involves a transseptal approach. Routinely, TEE is being utilized to support guidance during the procedure and in order to assess pre- and postoperative severity of MR.

What can I do intraoperatively to assist the surgeon and optimize patient care? The procedural team looks to the anesthesia provider for prompt response to acute hemodynamic perturbations, clear communication of significant changes in the patient’s condition and expertise in procedural TEE and image guidance.

Monitoring

  • ASA standard monitors (EKG, noninvasive blood pressure, pulse oximetry, capnography, temperature)

  • Radial arterial line (side discussed with procedure team as radial may be used for case)

  • Central venous line (Pulmonary artery catheter may be considered in TAVI cases with pre-existing pulmonary hypertension)

  • TEE (for us with GA or available for possible conversion to GA in MAC cases)

  • Defibrillation pads

  • Depth of anesthesia/sedation (processed EEG, e.g., BIS monitor)

  • Optional cerebral oximetry

  • Foley catheter (e.g., urine output)

  • Sidestream capnography

  • For all transapical aortic valve replacements (TA-AVR), general anesthesia is required.

b. If the patient is intubated, are there any special criteria for extubation?

No special criteria for extubation other than consideration that the patient will be flat for period of time due to recent cannula removal.

c. Postoperative management

  • Analgesic modalities: generally, most percutaneous valve procedures do not result in significant pain. However, it may be indicated to treat pain with i.v. opioids initially, conversion to oral regimen as soon as possible. Adjunct analgesia with paracetamol, oxycodone.

  • After general anesthesia, aim for early extubation (cath lab or within 2 hours in ICU)

  • Ensure postoperative normothermia, normovolemia, normoxemia (O2 per face mask or nasal cannula)

  • Ensure analgesia per local infiltration (intercostal if transapical approach for TAVI) and i.v. (1g acetaminophen i.v. or 650 mg p.o, oxycodone 5-10 mg p.o. prn)

  • Control access sites and distal limb perfusion

  • Control temporary pacemaker function

  • Transfer to IMC or ICU on monitoring and O2 with telemetry monitoring and backup VVI pacing (2 – 4 post-op days) in TAVI cases as these patients have a high incidence of AV block (up to 25%)

  • Anticoagulants should be discontinued and resumed per hospital standard

  • Activated clotting time (ACT) should be monitored per hospital standards

  • Daily aspirin (81 to 325 mg/day) and daily clopidogrel (75 mg/day) (or ticlopidine, if clopidogrel is contraindicated) for at least three months following any TAVI procedure. Resume clopidogrel in all patients that were previously on it. Occasional aspirin and warfarin for patients previously on warfarin.

  • Continue antibiotic at 6 hours and 12 hours post-operatively

  • What are the most common intraoperative complications and how can they be avoided/treated? Prioritize them by urgency: a) Cardiovascular (arrhythmia, coronary obstructions, pericardial tamponade) – avoid perioperative tachycardia, hypotension and loss or normal sinus rhythm., b) neurologic (stroke rate of up to 5% due to embolization of atherosclerotic plaques, aortic dissection, occult hemorrhagic shock, delirium, confusion) – avoid long-acting benzodiazepines and narcotics in the elderly, maintain sufficient blood pressure in line with preoperative values (e.g. pulse pressure), c) pulmonary (pulmonary edema, obstructive airway reaction) – avoid excessive volume therapy and triggers for airway reaction.