With increasing implantation of coronary artery stents over the past 2 decades, it is inevitable that anesthesiologists practicing in the outpatient setting will need to determine whether these patients are suitable for procedures at a free-standing ambulatory surgery center (ASC). Appropriate selection of patients with coronary artery stents for a procedure in an ASC requires consideration of factors that affect the balance between the risk of stent thrombosis due to interruption of antiplatelet therapy and the thrombogenic effects of surgery, and the risk of perioperative bleeding complications that may occur if antiplatelet therapy is continued. Thus, periprocedure care of these patients presents unique challenges, particularly for extensive surgical procedures that are increasingly scheduled for free-standing ASCs, where consultation and ancillary services, as well as access to percutaneous cardiac interventions, may not be readily available. Therefore, the suitability of the ambulatory setting for this patient population remains highly controversial. In this Pro-Con commentary, we discuss the arguments for and against scheduling patients with coronary artery stents in free-standing ASCs.
Free-standing ambulatory surgery centers (ASCs) are facilities that perform same-day diagnostic and therapeutic procedures and are not attached to an acute care hospital.1 Free-standing ASCs are facilities that are physically separated from the hospital, and therefore, access to consultation, ancillary services (eg, laboratory, pharmacy, radiology, or blood bank), and percutaneous cardiac interventions may not be readily available. Increasing migration of surgical procedures from hospitals to ASCs has occurred because of lower costs achieved by ASCs compared to hospital-based outpatient departments2 and the perioperative care model at ASCs that make them more convenient and attractive to patients and surgeons.3 In addition, there are increasing pressures placed by stakeholders, including surgeons and proceduralists, who may jointly own ASCs, to expand the caseload so as to maintain economic viability of the facility. As a result, patients with significant comorbidities are frequently being scheduled for increasingly extensive surgical procedures (eg, knee and hip arthroplasty, spine surgery, thyroid/parathyroid surgery, and hysterectomy) in ASCs.4
Coronary artery disease (CAD) is highly prevalent among the surgical population of the United States and is a well-known risk factor for perioperative major adverse cardiovascular events (MACEs).5,6 In addition to medical therapy, treatment of CAD often includes minimally invasive percutaneous coronary interventions (PCIs), which usually consist of balloon angioplasty and coronary stent deployment.7–9 In fact, PCI is one of the most commonly performed therapeutic procedures in modern medicine.10 It is expected that patients with coronary stents will increasingly present for noncardiac surgery.11 It is estimated that up to 25% of patients who have coronary artery stent implantation will undergo noncardiac surgery within 2 years of their cardiac intervention.12
With increasing implantation of coronary artery stents over the past 2 decades,13,14 anesthesiologists practicing in outpatient settings will need to determine whether these patients are suitable for ambulatory procedures. Appropriate selection of patients with coronary artery stents requires consideration of factors that affect the balance between the risk of stent thrombosis due to interruption of antiplatelet therapy and the thrombogenic effects of surgery, as well as the risk of perioperative bleeding complications that may occur if antiplatelet therapy is continued.7,9,15–20 Given the potential comorbidity burden for this patient population and the complications associated with stent thrombosis and/or perioperative bleeding, periprocedure care of these patients can be challenging, particularly in free-standing ASCs. Therefore, the suitability of ASCs for this patient population remains highly controversial. In this Pro-Con commentary, we discuss the arguments for and against scheduling patients with coronary artery stents in free-standing ASCs.
PRO: ASC SETTING IS SUITABLE FOR A PATIENT WITH CORONARY STENTS
The presence of previous PCI, per se, may be indicative that the patient has a history of significant CAD and multiple cardiovascular risk factors (eg, hypertension, diabetes mellitus, and chronic renal disease), which can increase the risk of perioperative cardiac morbidity.5,7,9 However, in practice, only patients with optimized comorbid conditions (ie, American Society of Anesthesiologists [ASA] physical status of ≤III) are scheduled for procedures in an ASC,4 thus reducing the risk of perioperative MACE. Furthermore, the overall perioperative risk of MACE related to ambulatory surgery seems to be low, as reported by a study that found a 30-day incidence of myocardial infarction (MI) after outpatient surgery of about 0.1%.21 The combination of low overall perioperative risk of MACE related to ambulatory surgery and the well-optimized patient who presents for ambulatory surgery makes it possible to safely care for these patients in an ASC.
Patients with coronary stents are considered vulnerable to MACE related to stent thrombosis.22 Understanding the risk factors of stent thrombosis should allow appropriate patient selection and improve patient safety. The risk factors for stent thrombosis in the setting of elective surgery include the invasiveness of the scheduled surgical procedure, the indication for stent implantation, the type and number of stents implanted, the degree of revascularization achieved after PCI, the time elapsed since stent placement, and the need to hold antiplatelet therapy (Table 1).23
|Invasive open surgical procedure|
|Stent placed for acute coronary syndrome|
|Type and number of stents|
|First-generation drug-eluting stents|
|Three or more stents implanted|
|Long stents (>60 mm)|
|Bifurcated stents or bifurcation with 2 stents implanted|
|Previous stent thrombosis or inadequate antiplatelet therapy|
|Diffuse multivessel disease|
|Left ventricular ejection faction <30%|
|Diabetes mellitus requiring insulin|
|End-stage renal failure requiring dialysis|
The invasiveness of the surgical procedure and associated proinflammatory response corresponds with the perioperative prothrombotic state.24 Although invasive procedures are increasingly performed in ASCs, most outpatient procedures are minimally invasive (eg, gastrointestinal endoscopic procedures, cataract surgery, cosmetic surgery, arthroscopy, etc.).25,26 Therefore, compared to inpatient surgery, the overall risk of adverse thrombotic events in this population is expected to be lower.27 The indication for PCI is another risk factor for MACE after surgery. It has been reported that the odds of postoperative MACE are about 5× higher within 3 months and 2× higher after 12 months of PCI when coronary stents are implanted to treat acute coronary syndrome (ACS).28 Of note, about two-thirds of PCI cases are performed on patients without ACS. Importantly, even the high-risk patients with a history of stent implantation for ACS are considered to have transitioned to stable ischemic heart disease after 1 year if they are symptom-free during this period.9
Reports of catastrophic postoperative outcomes after noncardiac surgery attributed to stent thrombosis were common in the early era of PCI.9,29 However, advances in revascularization techniques and the introduction of new generations of drug-eluting stents (DESs) have significantly reduced the risk of stent thrombosis and MACE after elective surgery. A study in the Veterans Affairs population (matched 20,590 surgical patients to 41,180 nonsurgical patients) conducted between 2000 and 2010 found that the incidence of postoperative acute MI and/or revascularization decreased from 9% when surgery was performed within the first 6 weeks of PCI to 2.3% when surgery occurred after 6 months from PCI.30 Of note, the risk of MACE 6 months after DES implantation in a subset of patients having outpatient procedures was similar to those who did not have surgery (1.5% vs 1.1%).30 Other studies have also found MACE rates of about 2% when elective surgery takes place >6 months after PCI.31,32
Due to concerns of stent thrombosis, dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor (eg, clopidogrel, prasugrel, ticagrelor, or cangrelor) is recommended for 6 months after newer DES implantation and 12 months after older DES implantation.9 Use of bare metal stents (BMSs) reduced the incidence of coronary thrombosis after PCI but was associated with increased risk of stent restenosis and repeat revascularization. According to current guidelines,9 elective surgery can be performed after 30 days from BMS implantation, and DAPT may discontinued for the procedure. After the high-risk period, patients continue to receive aspirin, which has not been shown to increase perioperative bleeding complications.9,31,33 In fact, perioperative aspirin is more likely to benefit rather than harm patients with previous PCI.34 Given the elective nature of procedures performed in ASCs, it is feasible to schedule the desired procedure at least 6 months after DES and 1 month after BMS, thus reducing the risk of MACE.
The decision to perform elective procedures in patients on DAPT depends on the perceived risk of bleeding complications. Risk factors for antiplatelet therapy-related bleeding complications include the type of surgical procedure (eg, closed-cavity procedures, such as intracranial surgery, intramedullary spine surgery, and transurethral prostate surgery), extensive open surgery, preoperative hemoglobin <12 g/dL, age, sex, functional status, kidney function, history of high-risk CAD, and active cancer.35 Many ambulatory surgical procedures have a low risk of bleeding and can be safely performed in ASCs in patients taking DAPT. Some national and international specialty societies have provided guidance in this respect. For example, the American Society for Gastrointestinal Endoscopy (ASGE),36 the Royal College of Ophthalmologists,37 and the American Society of Interventional Pain Physicians (ASIPP)38 provide a classification of common procedures based on their potential risk of bleeding in patients on antithrombotic therapy (Table 2). Recently, the European Society of Anaesthesiology and Intensive Care and the European Society of Regional Anaesthesia recommended that superficial nerve blocks and interfascial plane blocks may be performed in patients on antiplatelet therapy.39 DAPT could be continued for some urologic procedures, including ureteroscopy and cystoscopy.40 In patients undergoing ambulatory minor cosmetic surgery, it is accepted that monotherapy with aspirin is safe to continue, but evidence regarding continuation of clopidogrel is conflicting.41 Of note, if necessary, DAPT may be temporarily discontinued 5 to 7 days before surgery with minimal increase in stent thrombosis risk.9
|Low risk for bleeding procedures (may continue dual-antiplatelet therapy)||High risk for bleeding procedures|
|American Society for Gastrointestinal Endoscopy 36|
|Diagnostic esophago-gastro-duodenoscopy, colonoscopy, or flexible sigmoidoscopy||Polypectomy|
|Endoscopic retrograde cholangiopancreatography with stent placement or papillary balloon dilation without sphincterotomy||Biliary or pancreatic sphincterotomy|
|Diagnostic balloon-assisted and capsule enteroscopy||Treatment of varices|
|Endoscopic ultrasound without fine needle aspiration||Percutaneous endoscopic gastrostomy placement|
|Argon plasma coagulation||Therapeutic balloon-assisted enteroscopy|
|Barrett’s ablation||Endoscopic ultrasound with fine needle aspiration|
|Endoscopic submucosal dissection|
|Pneumatic or bougie dilation|
|Royal College of Ophthalmologists 37|
|Cataract surgery under topical or subtenon anesthesia||Peri- or retro-bulbar anesthesia|
|Corneal surgery||Glaucoma surgery|
|Oculoplastic surgery: chalazion and eyelid cyst/lesion removal||Vitreo-retinal surgery|
|Strabismus surgery||Endoresection or biopsy of intraocular tumors|
|Oculoplastics: blepharoplasty and postseptal eyelid surgery|
|Temporal artery biopsy|
|American Society of Interventional Pain Physicians 38|
|Trigger point and muscular injections||Cervical, thoracic, and interlaminar epidurals above L4-L5|
|Peripheral joint injections||Cervical, thoracic, and lumbar above L3 transforaminal epidural injections|
|Peripheral nerve blocks||Spinal cord stimulator trial and implant|
|Sacroiliac joint and ligament injections and nerve blocks||Percutaneous adhesiolysis with interlaminar or transforaminal approach|
|Caudal epidural injections||Percutaneous disk decompression (above L4/5)|
|Ganglion impar blocks||Sympathetic blocks (stellate ganglion, thoracic splanchnic, and celiac plexus)|
|Thoracic and cervical intradiscal procedures|
|Vertebral augmentation, lumbar (above L4), thoracic, and cervical|
|Intrathecal catheter and pump implant|
Overall, the majority of patients with coronary stents scheduled for ambulatory surgery are suitable for free-standing ASCs. In addition to preoperative optimization of comorbid conditions, preoperative identification of risk factors for stent thrombosis (Table 1) and the need for continuation/discontinuation of DAPT should reduce the perioperative risk of stent thrombosis and bleeding complications. Most of the procedures performed in this setting are minimally invasive and, thus, have a low risk of stent thrombosis and perioperative bleeding. Given the elective nature of the procedures, they can be performed after the risk of stent thrombosis is significantly reduced (usually 6 months after DES placement and 1 month after BMS). The best timing for elective surgery is when patients are off of DAPT and are only on aspirin. Also, several procedures can be performed without discontinuation of DAPT (Table 2). Patient safety can be maintained with appropriate patient selection (Table 3).
|Patient is scheduled for a noninvasive or minimally invasive diagnostic or therapeutic procedure||Patient is scheduled for invasive open surgical procedure|
|Stent implanted to treat low-complexity coronary lesions (eg, coronary stents placed for treatment of short noncomplex lesions not including artery bifurcations or the left main coronary artery)||Reason for stent implantation was an acute coronary syndrome that occurred within 12 mo of ambulatory surgery|
|Time elapsed since stent placement is >1 mo for bare-metal stents and 6 mo for newer drug-eluting stents||High-complexity coronary artery lesions|
|Dual antiplatelet therapy has been discontinued and patient is only taking aspirin or the desired procedure can be performed without discontinuation of dual antiplatelet therapy||High risk of thrombosis ()|
|High risk of perioperative bleeding if antiplatelet therapy is continued ()|
|Dual antiplatelet therapy cannot be stopped before invasive surgery|
|Patients with conditions requiring dual antiplatelet therapy plus antithrombotic therapy (eg, oral anticoagulants)|
|Free-standing ambulatory center lacks immediate access to a facility with interventional cardiology services|
Finally, to maintain patient safety, anesthesiologists practicing in such ASCs should be involved in timely preoperative evaluation and patient selection, as well as enhance their knowledge and skill sets to manage complex patients. Early identification of complications including stent thrombosis and bleeding is critical for patient safety. Implementation of check lists, simulation drills with MACE scenarios, and protocols for prompt transition of care from the ASC to a hospital should improve preparedness of the ASC to manage patients with coronary stents. In the event of a perioperative coronary event, the ASC should be prepared to implement a rescue plan, which includes verification of the diagnosis of MACE with 12-lead electrocardiogram; early and appropriate treatment of severe pain, hypertension, or hypotension; administration of high-flow oxygen, aspirin, and beta blockers, if appropriate; and prompt transfer to a facility with interventional cardiology capabilities.42
CON: ASC SETTING IS NOT SUITABLE FOR A PATIENT WITH CORONARY STENTS
Patients with coronary stents can have significant cardiac disease and, therefore, are at an elevated risk of perioperative cardiac complications both from potential stent thrombosis and from myocardial ischemia from potential disease in the nonstented segments.43 Free-standing ASCs are not always equipped to manage such complex patients due to the lack of resources and personnel. Also, such complex patients require preoperative evaluation and optimization that is at least currently not routine in free-standing ASCs, as the patients are seen on the day of surgery. This might delay procedures and reduce ASC efficiency.44 More important, it might lead to inappropriate patient selection, which can compromise patient safety.4
Patients with stents implanted for ACS remain at risk of coronary stent-related complications for a longer time compared to patients with stents implanted for stable ischemic heart disease.28,45 It is important to recognize that BMS is usually selected for patients with higher cardiac risk scores, those with high risk of bleeding, patients who cannot tolerate DAPT because of active bleeding or nonadherence to medical therapy, and patients needing urgent operations.9 Higher rates of cardiac events after surgery have been observed in patients with BMS compared to DES.30 Therefore, although DAPT can be discontinued after 30 days of BMS implantation, these patients may have increased risk of cardiac complications for the same reasons that led to the decision to implant a BMS instead of a DES.
Interruption of DAPT before surgery is an independent correlate for MACE. Premature discontinuation of DAPT is the strongest predictor of stent thrombosis and is associated with an unacceptable rate of acute MI and a fatality rate as high as 45%.46 Therefore, at a minimum, elective surgery, and thus ambulatory procedures, should be delayed if patients are on DAPT that needs to be discontinued. Although there are recommendations for an optimal duration of DAPT,9 these need to be modified based on interplay between indications for stent placement, stent characteristics (eg, location, length, type, and number), and patient characteristics (eg, comorbidities, age, and use of other anticoagulants). With introduction of newer types of coronary stents and broadening indications for stent placements, the optimal duration of DAPT and the best perioperative care have been evolving, leading to challenges in the decision-making to offer the ambulatory setting for patients with coronary stents. To complicate matters, a recent observational study found no evidence for protective effects of DAPT from perioperative MACE in patients who have undergone previous PCI, while the risk of harm from bleeding was increased.47 Of note, the study lacked long-term follow-up and standardized monitoring of MACE.47 Even after discontinuation of DAPT, aspirin should be continued indefinitely and can increase the risk of perioperative bleeding complications.
The characteristics of the stented coronary lesion and the PCI procedural complexity should also be considered when offering ambulatory surgery to patients with coronary stents. Lesions consisting of high-risk vulnerable plaques, long-stenosed coronary segments, lesions located in the bifurcation of a vessel, complex lesions of the left main coronary artery, or multivessel disease are associated with increased risk of ACS.48–51 Similarly, PCI with implantation of multiple stents, treatment of a bifurcation lesion with 2 stents, incomplete coronary revascularization, malposition of the stent struts, or fracture or discontinuity in the deployed stents may modify the flow characteristics and has been associated with increased incidence of adverse cardiac events.11,23,46,52–55 Extended DAPT is of potential benefit in this patient population.56,57 As all the details about the PCI intervention and anatomy of the coronary lesions may not be readily available to anesthesiologists in the rapid-paced ASC environment, patients with complex lesions may be inadvertently scheduled at ASCs, exposing them to unnecessary perioperative risk of MACE.
Patients at high risk of thrombosis may not be suitable candidates for ambulatory surgery, particularly for invasive surgical procedures. For example, patients with insulin-treated diabetes mellitus have a 3-fold increase in the risk of stent thrombosis compared to nondiabetic patients.58,59 Similarly, heart failure with a left ventricular ejection fraction <30% has been associated with a nearly 3× times increased risk of early stent thrombosis.23 Advanced malignant disease is considered an acquired thrombophilic state, and therefore, poses a high risk of perioperative stent thrombosis.60 Patients with a previous history of stent thrombosis are at particularly high risk of perioperative ACS. It is estimated that about 20% of this patient population experience stent reocclusion within 3 years of the first occlusion, with a cumulative risk of cardiac death of about 28%.61,62 Other clinical factors, including advanced age, current smoking status, chronic renal failure on dialysis, liver disease, anemia, thrombocytopenia, inherited coagulation disorders, and thrombocytosis states, have also been implicated as risk factors for perioperative acute and subacute stent thrombosis.11,16,63–65
Atrial fibrillation shares similar risk factors with ACS, and therefore, is often found (5% to 23%) in patients with coronary stents.66 According to recent guidelines,67 prevention of stroke and stent thrombosis in this patient population should be achieved with dual antithrombotic-antiplatelet therapy, which includes combination of vitamin K antagonists or a direct oral anticoagulant (apixaban, dabigatran, edoxaban, or rivaroxaban) and a P2Y12 inhibitor. This more intense therapy significantly increases the risks of perioperative bleeding complications. Although it has been suggested that interruption of oral anticoagulants with continuation of antiplatelet therapy is reasonable for patients with atrial fibrillation and recent stent implantation,31 no specific recommendations currently exist for the perioperative management of this patient population.
Another major determinant of suitability for ambulatory surgery is the invasiveness and complexity of the surgical procedure because it influences not only the risk of stent thrombosis but also the risk of perioperative bleeding complications.30 High-risk patients with coronary stents for whom DAPT may not be stopped are not good candidates for invasive/extensive outpatient surgical procedures.30
Finally, patients who develop an ACS in the ambulatory facility will need immediate angiography and revascularization, thus requiring immediate transfer to an acute care hospital. Mortality after ST elevation myocardial infarction (STEMI) increases in direct proportion with the time elapsed between the onset of symptoms and reperfusion of the culprit vessel.68–70 Studies have revealed that for every 30-minute delay in PCI, the absolute risk of in-hospital mortality increases by 1%, and the risk of 1-year mortality increases by 7.5%.71 There is consensus among international scientific societies that the time between arrival to the hospital and balloon angioplasty (door-to-balloon time) should be no longer than 90 minutes.9,72–74 However, delays in treatment may occur related to the time needed to transfer the patient from the ASC to a PCI-capable hospital.
Overall, safe care of these patients requires consideration of the abovementioned variables. The patients with coronary stents are complex, and the duration of DAPT to mitigate the potential of stent thrombosis is variable and controversial. There may be delay in procedures as well as in discharging home, leading to reduced efficiency. Therefore, these patients may not be suitable for a free-standing ASC (Table 3).
In this era of value-based purchasing, the trend of performing complex procedures on challenging patients in free-standing ASCs will continue. It is no longer acceptable to demand that only healthy patients (ASA physical status I and II) are scheduled in free-standing ASCs. Considering the existing pressure to move more complex cases to ASCs, the decision to schedule patients with coronary stents in ASCs should be well informed.
Ambulatory procedures can be safely performed in ASCs for patients with coronary stents undergoing minimally invasive procedures, with lower comorbidity burden, low-complexity coronary lesions, longer time since stent implantation, and when DAPT has been discontinued or DAPT can be continued (Figure). On the other hand, procedures requiring temporary cessation of antiplatelet therapy for patients with high-risk lesions and complex PCIs or those with BMS warrant caution.
Appropriate screening and management before the day of surgery are needed. Preoperative assessment of patients with coronary stents should be aimed to determine whether the patient’s comorbidities are optimized, to estimate the perioperative risk of MACE due to stent thrombosis and coronary disease in the nonstented segments, and to evaluate the risk of perioperative bleeding or hematoma when antiplatelet therapy cannot be discontinued before surgery. Careful analysis of these 3 factors is of critical importance. If deemed necessary, patients should be referred for timely preoperative cardiology evaluation to determine the stability of patients’ CAD and provide instructions about appropriate management of antiplatelet therapy. Of note, ambulatory surgery requiring temporary cessation of DAPT for patients with high-risk lesions and complex PCI warrant discussion between the cardiologist, surgeon, anesthesiologist, and the patient. Involving the patient in decision-making (shared decision-making) requires transparency and education regarding the benefit and risk tradeoffs of performing the procedure at a free-standing ASC.3 Patients should be instructed regarding medications that need to be held or taken before surgery as well as the timing of restarting medications after surgery.
Finally, characteristics of ASCs prepared to take care of complex patients undergoing complex procedures include accreditation status, adequate qualified staffing, clinicians with local hospital admitting privileges, availability of technology and equipment, established emergency response protocols, transfer agreement with the local hospital and proximity of the ASC to a PCI-capable hospital, or, the best scenario, an angiography suite with ambulatory PCI capability.75
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