Preoperative cardiopulmonary assessment for video-assisted thoracoscopic surgery (VATS) pulmonary resection: a narrative review

Introduction

Background

Lung cancer remains the leading cause of cancer death in the United States in 2024 (1). Despite significant treatment advances in the past decade, including the use of targeted molecular therapies and immunotherapy, surgery remains the mainstay of treatment for early-stage lung cancer (2). The advent of video-assisted thoracoscopic surgery (VATS) has largely replaced the thoracotomy and has significantly improved the morbidity and mortality associated with pulmonary resections for lung cancer (3-6). However, thoracoscopic surgery still has a higher risk profile than most surgeries and is associated with an elevated risk of perioperative cardiac and pulmonary complications (7,8). Major perioperative cardiac complications include myocardial infarction (MI) and ischemia, heart failure, arrhythmia, and cardiac death, while major perioperative pulmonary complications include postoperative respiratory failure, hypercarbia, hypoxemia, pulmonary embolus, pneumonia, chronic obstructive pulmonary disease (COPD) exacerbation, and severe atelectasis. Risk factors for these complications can be broadly broken down into patient-specific factors and surgery-specific factors. Many surgery-specific risk factors can be optimized—for example, lung-protective ventilation strategies while on one-lung ventilation can help to reduce pulmonary injury and subsequent pulmonary complications (9). To this end, many institutions have instituted enhanced recovery after surgery (ERAS) pathways, a standardized set of evidence-based perioperative interventions that reduce the rate of perioperative complications and expedite patient recovery.

However, it is also essential that surgeons identify a patient’s intrinsic cardiac and pulmonary risk factors before proceeding to the operating room. A focused preoperative examination may reveal a patient’s previously undiagnosed congestive heart failure, allowing time for cardiac optimization to reduce their risk of acute postoperative decompensation. Knowledge of a patient’s preoperative cardiac status helps to guide post-operative decision-making—like when to restart goal-directed medical therapy (GDMT). Similarly, preoperative pulmonary function testing (PFT) is essential to assess the patient’s pulmonary status. Ensuring adequate post-operative lung function is vital, especially before a large resection or pneumonectomy. The widespread implementation of ERAS protocols, with an emphasis on preoperative optimization, helps to facilitate appropriate cardiopulmonary assessment (9). In cases where the preoperative risks remain high despite optimal medical management, this evaluation allows for a more frank and informed discussion with the patient about the risks of their upcoming lung resection, and in some cases warrants consideration for non-surgical treatment alternatives.

Objective

The objective of this narrative review is to summarize various guidelines that thoracic surgeons ought to be aware of and implement in their preoperative screening of patients before a VATS pulmonary resection for lung cancer. While much has been previously published on the subject of either the preoperative cardiac or pulmonary evaluation, this review fills a knowledge gap by discussing both the cardiac and pulmonary evaluation in one document. It describes several preoperative risk assessment tools and the current state of recommended biomarkers. It then ties together comprehensive guidelines from different authoritative bodies, including the American Heart Association (AHA)/American College of Cardiology (ACC), European Society of Cardiology (ESC), Canadian Cardiovascular Society (CCS), and the Japanese Circulation Society (JCS), along with the American College of Chest Physicians (ACCP), European Respiratory Society (ERS), British Thoracic Society (BTS), and the Japanese Association of Chest Surgery (JACS), into a single document. It highlights some of the newer updates and recommendations in the preoperative workup of patients prior to lung cancer resection, and serves as a useful overview for thoracic surgeons on a critically important aspect of the care of their patients with lung cancer. We present this article in accordance with the Narrative Review reporting checklist (available at https://vats.amegroups.com/article/view/10.21037/vats-24-36/rc).

Methods

A narrative review of the literature was performed using a search of PubMed, ClinicalKey, and UpToDate using a variable combination of the terms “video-assisted thoracoscopic surgery”, “preoperative assessment”, “preoperative cardiac risk stratification”, “preoperative pulmonary risk stratification”, and “pulmonary function testing”. Articles were hand-selected and citation chaining was performed to identify relevant studies. Whenever possible, the authors cited original studies, systematic reviews, meta-analyses, or randomized controlled trials. All articles cited have undergone peer review and been published and indexed within PubMed. The articles cited were written in English between 1961 and 2024. Please see Table 1 for the search summary strategy.

Cardiac preoperative risk assessment

Guidelines for perioperative cardiovascular assessment and management

The late 1950s and 1960s saw some of the first publications to meaningfully study perioperative morbidity and mortality. In 1961, Dripps et al. noted the association between the physical fitness of the candidate and their perioperative death (10). In 1977, Goldman et al. published the first Cardiac Risk Index (11). Since then, the assessment and management of perioperative cardiac risk has grown into a detailed field of study, with numerous national/multinational societies producing comprehensive consensus guidelines to help mitigate major perioperative cardiac events (12-16). In the United States, the AHA, in conjunction with the ACC, publishes its Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery. The most recent edition, published in September 2024, will be discussed at length in this review (12). Similar guidelines are published in English by the ESC, the CCS, and the JCS (13-15). Several notable differences in approach between these guidelines will be highlighted herein.

Initial cardiac evaluation and risk factors

The preoperative cardiac risk assessment begins in the clinic while evaluating a patient diagnosed with lung cancer. The surgeon starts with a focused history and physical exam, including a detailed personal cardiac history and family history of heart disease. Other significant risk factors include patient age, gender, smoking status, and comorbidities including diabetes mellitus, dyslipidemia, hypertension, peripheral artery disease, chronic kidney disease, prior cerebrovascular accidents, or obstructive sleep apnea. It is important to note any prior cardiac surgeries or interventions, such as a prior coronary artery bypass grafting, valve replacement, or percutaneous coronary intervention, and any implanted devices, such as coronary stents or pacemakers. It is also important to document current medications, especially anticoagulants or antiplatelet medications, beta-blockers, statins, and angiotensin-converting enzyme inhibitors or angiotensin-II receptor blockers. On physical exam, the surgeon will evaluate for jugular venous distension, peripheral edema, pulmonary edema, heart rate irregularities, and listen for any heart murmurs or S3 heart sounds, which may indicate previously undiagnosed valvular disease or heart failure (17).

Functional status assessment

A key element of the history and physical exam is to assess the patient’s functional status. This refers to a patient’s global fitness level to perform activities of daily living. Poor functional status is associated with significantly higher perioperative cardiac risk. The use of metabolic equivalents (METs) is a common way to quantify a patient’s functional status based on their body’s ability to effectively utilize oxygen. Strictly defined, one MET equals 3.5 mL O₂ uptake/kg/min (18). In practice, one MET is considered the energy required to eat, dress, or use the toilet. Patients are deemed to have poor functional status if they are unable to perform four METs, which is about equivalent to the ability to walk up two flights of stairs or walk on level ground at around 3–4 miles per hour (an average walking pace) (17). Those patients unable to perform four METs were shown in one study to have double the rate of perioperative myocardial ischemia and other cardiovascular events (19,20).

There is, however, conflicting data regarding using this simple assessment of a patient’s functional status. In 2018, the prospective, international METS trial found no association between patient-reported METs and postoperative cardiac events (20). Instead, this trial found that the Duke Activity Status Index (DASI), a 12-point questionnaire in which the patient self-reports their ability to complete a detailed list of household tasks, could predict postoperative MI and cardiac death more accurately (20). The DASI, published in 1989, was created by measuring the VO₂max of 50 patients during exercise. Investigators then built the 12-item questionnaire to accurately correlate with the patients’ measured VO₂max, with a Spearman correlation of 0.81 (P<0.001). This was then validated in a second cohort of 50 patients, with a lower but still highly significant Spearman coefficient (0.58, P<0.001) (21). Given the findings in the METS trial, the DASI questionnaire is the recommended method of functional capacity assessment by AHA/ACC and the JCS in their guidelines (12,15). The ECS and CCS mention both functional status assessments—METs and the DASI—but do not strongly recommend one or the other (13,14). In practice, the authors have found METs to be helpful as a quick first screening tool, with the DASI serving as a more comprehensive secondary screening tool for patients with more questionable functional status.

Risk assessment models

As previously mentioned, the first Cardiac Risk Index was published by Goldman et al. in 1977 (11). This was revised by Detsky et al. in 1986 to the Modified Cardiac Risk Index, which was more accurate but inconvenient to calculate (22). By 1999, Lee et al. published the Revised Cardiac Risk Index (RCRI), a simplified version of Detsky’s that only utilized six variables while maintaining its predictive value (7). Written in 1999, the RCRI estimates the risk of experiencing a major perioperative cardiac event, which includes MI, pulmonary edema, ventricular fibrillation, cardiac arrest, or complete heart block. The RCRI has six questions and assigns one point each for a positive response to each question. The first question determines if a surgery is considered high-risk. Given that all intra-thoracic surgery is considered high-risk in the RCRI, all patients scheduled for a VATS pulmonary resection automatically start with a 1.3% risk of a major cardiac adverse event. Subsequent questions include: (I) a history of ischemic heart disease (e.g., history of MI, positive exercise stress test, complaints of chest pain, etc.); (II) a history of heart failure; (III) a history of cerebrovascular disease; (IV) a history of diabetes mellitus requiring insulin therapy; or (V) a preoperative serum creatinine level >2.0 mg/dL. In the absence of risk factors, there is a 0.4% chance of a major adverse cardiac event (MACE). One risk factor carries a 1.3% chance of MACE; two risk factors, 3.6% risk; and three or more risk factors carry a 9.1% risk of MACE occurring in the perioperative period (7,23).

The RCRI, while useful and straightforward, is not a perfect risk estimator. It has been shown to underestimate risk in major vascular surgery and is not appropriate for use in cases of emergency surgery (23,24). Two more detailed scoring systems have subsequently been created using the American College of Surgeons’ (ACS) National Surgical Quality Improvement Program (NSQIP) database. In 2011, Gupta et al. created the Myocardial Infarction and Cardiac Arrest (MICA) score. This score incorporates a more detailed list of procedures (each with its own associated risk factor). It also includes patient age, functional status, and the American Society of Anesthesiologists (ASA) score. The MICA score has been well-validated to predict 30-day major cardiac events with a greater degree of accuracy than the RCRI (25). In 2013, the NSQIP database was used to create the extensive, 21-variable ACS Surgical Risk Calculator (ACS-SRC). This provides the most detailed assessment of both cardiac risks and other post-operative complications and outcomes for patients undergoing a wide range of surgeries, and has been validated in American and international trials (26,27). All four of the guidelines discussed in this review credit improved overall risk discrimination of the ACS-SRC. However, there is a concern that the MICA and ACS-SRC are inconvenient to use and underestimate cardiac risk because serial troponin monitoring was not used to create these two tools. Thus, given its simplicity (and ease of incorporating relevant biomarkers), the RCRI remains the most common screening tool today, and is recommended by the AHA/ACC, ECS, CCS, and JCS in the initial evaluation of cardiac risk (12-15). In our practice, the RCRI remains our most-used risk assessment tool. We may calculate the ACS-SRC score for high-risk patients preparing for larger cases to help quantify the risks for patients and their families during our informed discussion of the risks and benefits of surgery.

Serum biomarkers

In general, the AHA/ACC guidelines recommend against drawing preoperative lab tests unless the result of the tests would change management (12). However, two key labs—the cardiac troponin (cTn) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) can help predict cardiac risk beyond what the history and risk prediction models alone may reveal.

cTn is a marker of myocardial stress and ischemia, and multiple recent prospective studies and meta-analyses have documented a strong association between elevated preoperative cTn levels and postoperative MACEs (28-31). Recently, a meta-analysis published by Zhao et al. found that an elevated preoperative troponin (defined as greater than the 99^th percentile of normal troponin values) correlated with higher short-term MACEs [risk ratio (RR) =2.92; 95% confidence interval (CI): 1.96–4.37], short-term mortality (RR =5.39; 95% CI: 3.21–9.06), and long-term mortality (RR =2.90; 95% CI: 1.83–4.59). This study also found that when the cTn was combined with the RCRI, it improved the ability to accurately classify the preoperative cardiac risk of patients (by an increase in the concordance index (C-index), a measure of goodness-of-fit of the area under the receiver operating characteristic curve, by 0.058 to 0.109) (28).

The NT-proBNP is a marker of cardiac wall stretch, and elevated preoperative levels have also recently been shown to be associated with increased postoperative MACEs (32-34). A large multinational prospective cohort study of patients undergoing inpatient noncardiac surgery published by Duceppe et al. demonstrated that increasing levels of preoperative NT-proBNP corresponded with a significant and incremental increase in combined postoperative cardiac death and myocardial injury. They found that, compared to patients with preoperative NT-proBNP levels <100 pg/mL, those with NT-proBNP levels between 100–200 pg/mL, 200–1,500 pg/mL, and greater than 1,500 pg/mL corresponded with adjusted hazard ratios of 2.27 (95% CI: 1.90–2.70), 3.63 (95% CI: 3.13–4.21), and 5.82 (95% CI: 4.81–7.05) for the composite outcome of cardiac death or myocardial injury. They also found that, by adding a serum NT-proBNP level to the RCRI, they calculated a net improvement in reclassification of patients by 258 patients for every 1,000 patients assessed (32).

As a result of these studies, both the AHA/ACC and ECS state that it is reasonable to measure a preoperative NT-proBNP and/or a cTn for patients with either known cardiovascular disease, those over age 65 years, or those over 45 years with symptoms concerning for cardiovascular disease preparing for intermediate or high-risk surgery. They do not recommend preoperative biomarker testing for low-risk patients preparing for low- or intermediate-risk surgeries (12,13). The Canadian and Japanese guidelines recommend measurement of the NT-proBNP in similar circumstances (14,15). In our practice, patients with a significant cardiac history will be evaluated by our cardiology team, and often will have a preoperative cTn and NT-proBNP drawn prior to surgery.

Diagnostic testing

The AHA/ACC’s guidelines for perioperative cardiovascular management also specify which subsets of patients may benefit from further diagnostic testing. Specifically, this guideline discusses when to obtain a preoperative electrocardiogram (ECG), transthoracic echocardiogram (TTE), coronary computed tomography angiography (CCTA), cardiac magnetic resonance imaging (cMRI), stress testing (either exercise or pharmacologic stress testing), and invasive coronary angiography. These recommendations are briefly summarized in Table 2.

Stepwise approach to preoperative cardiac testing

The AHA/ACC guidelines for perioperative cardiovascular management present a comprehensive, approach to evaluating cardiac risk in a preoperative patient. Readers ought to reference this guideline for a more detailed, step-wise assessment of preoperative risk. However, in brief, evaluation starts with a cardiac history to identify any especially high-risk diagnoses (e.g., severe valvular disease, severe pulmonary hypertension, etc.), which automatically qualifies patients for a more extensive cardiac workup, which includes an ECG, echocardiography (especially if there are new or worsening symptoms), and a consult to cardiology and the initiation of any warranted GDMT. In the absence of these high-risk diagnoses, one of the validated cardiac risk scoring algorithms (the RCRI, MICA, or ACS-SRC, for example) is used to determine if the patient is at elevated cardiac risk (deemed to be >1% risk of a major cardiac event). If the patient is low risk, they may proceed to VATS (or more appropriately, to the pulmonary risk stratification algorithm, to be discussed in the next segment). If the patient is deemed to be at elevated risk, they should receive an ECG, be started on any warranted GDMT, and have their functional status calculated. Those with elevated risk but appropriate functional status (typically either METS >4 or DASI score >34) may proceed with pulmonary testing and VATS. Those with poor functional status must have an educated discussion with their multidisciplinary medical team about risks and benefits of a VATS resection.

The ACA/ACC guidelines emphasize that no further testing is warranted if the patient understands the risks and is determined to proceed. However, if further workup and risk stratification is desired, a cTn and NT-proBNP can be obtained. Abnormal values may prompt further multidisciplinary care discussions and more extensive cardiac workup to include echocardiography (if not already performed), a stress test, and possibly a CCTA, with the initiation of any appropriate GDMT. After this testing, if the patient is deemed to be at exceptionally high cardiac risk, it may be more appropriate to contemplate alternate modes of therapy, such as chemotherapy and radiation without surgery, or initiation of palliative care. Of note, while many institutions may perform invasive coronary angiography for high-risk patients, current data does not demonstrate that this improves perioperative outcomes or reduces short-term perioperative cardiac events (12).

Pulmonary preoperative risk assessment

Pulmonary complications and risk factors

Pulmonary complications are the other significant cause of perioperative morbidity and mortality following lung resection (36). Many patients with lung cancer are elderly, have a history of cigarette smoking, and often have other pulmonary comorbidities, increasing their risk of major perioperative pulmonary complications. Specifically, major pulmonary complications include postoperative respiratory failure—defined as either prolonged ventilation greater than 48 hours, or the need for unplanned reintubation. They also include acute carbon dioxide retention, hypoxia, the development of acute respiratory distress syndrome, acute exacerbation of chronic conditions (like COPD or asthma), pulmonary embolus, pneumonia, severe atelectasis requiring bronchoscopy, or new oxygen requirement upon discharge (37). There is a great deal of overlap between cardiac and pulmonary risk factors. However, well-recognized pulmonary-specific risk factors include age, COPD, congestive heart failure, smoking, obstructive sleep apnea, interstitial lung disease, pulmonary hypertension, recent or ongoing respiratory infections, and poor nutrition (defined by albumin less than 3 g/dL) (38-46).

Pulmonary resection causes distinct physiological changes that increase the risk of postoperative pulmonary complications. Lung resection causes direct pulmonary dysfunction, not only by reducing lung volume but also by temporarily worsening chest wall dynamics. The use of minimally-invasive VATS, and later the utilization of robot-assisted thoracoscopic surgery (RATS), has significantly decreased the impact of chest wall dysfunction compared to thoracotomy. In the early 2000s, VATS was shown to lead to improved spirometric values [including the forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC)] at 1 and 2 weeks postoperatively, as well as improved postoperative partial pressure of oxygen (PaO₂) and oxygen saturation levels in the immediate postoperative period compared to thoracotomy (47). The loss in FEV₁ and FVC was determined to be only 15% with VATS compared to 23% and 29% with thoracotomy (48). Patients who underwent VATS also demonstrated a significantly improved 6-minute walk test at 1 week after surgery compared to those who underwent thoracotomy (49). A later randomized controlled trial performed in multiple hospitals within the United Kingdom’s National Health System also reported significantly decreased postoperative pain, shorter length of stay, and improved patient-reported quality-of-life associated with VATS compared to open thoracotomy (5). In recent years, the increasing use of RATS has shown comparable, and at times favorable, outcomes to VATS. Few studies directly analyze postoperative spirometric values of VATS compared to RATS. However, a meta-analysis published in 2018 demonstrated RATS to have improved 30-day mortality [0.7% vs. 1.1%; odds ratio (OR) =0.53; P<0.001] and reduced conversion to thoracotomy (10.3% vs. 11.9%; OR =0.57; P<0.001) compared to VATS, without any other significant differences in postoperative complications or length of hospitalization, implying that RATS has at least equivalent outcomes on pulmonary function compared to VATS (50).

Intra-operative anesthetic factors also influence postoperative outcomes. During one-lung ventilation, a substantial ventilation/perfusion (V/Q) mismatch develops, with the operative lung being perfused but not ventilated. Tidal volumes must be carefully regulated to avoid under-ventilating the nonoperative lung, which can lead to severe atelectasis, or over-ventilating, which can predispose to alveolar rupture secondary to overdistension. Over-ventilating the nonoperative lung also increases pulmonary vascular resistance, shunting blood flow preferentially to the non-ventilated lung, worsening the V/Q mismatch (51). In patients with pre-existing comorbidities, these physiologic changes increase the risk of postoperative hypoxemia, hypercarbia, prolonged ventilation, and other major pulmonary complications.

Preoperative pulmonary risk stratification

Current guidelines

Pulmonary risk assessment is a crucial component of the preoperative evaluation that follows cardiac risk stratification. PFTs have been used since the 1950s to identify which patients are at high risk for lung resection. In the early days, the “maximum breathing capacity” (now referred to as the “maximum voluntary ventilation”) was believed to be the most predictive pulmonary measurement (52). Today, most preoperative pulmonary evaluations follow the algorithm espoused in the “Physiologic Evaluation of the Patient With Lung Cancer Being Considered for Resectional Surgery”, published by the ACCP, the 3^rd edition of which was published in 2013 (53). Readers seeking a more detailed, step-wise pulmonary assessment ought to reference this guideline. Other notable guidelines, including the “ERS/ESTS clinical guidelines on fitness for radical therapy in lung cancer patients” published in 2009 by the ERS/European Society of Thoracic Surgeons (ESTS), and the 2010 “Guidelines on the radical management of patients with lung cancer” from the BTS, follow nearly identical algorithms (54,55). These guidelines have been reaffirmed with minimal changes in the “Guidelines for preoperative pulmonary function assessment in patients with lung cancer who will undergo surgery” published by the JACS in 2025 (56).

PFT and diffusion capacity

The first step in these guidelines is to perform cardiac risk stratification. If the cardiac risk is prohibitively high, the patient should not proceed to PFT. Assuming appropriate cardiac risk, the patient then undergoes PFT, including spirometry and measurement of the diffusing capacity of the lung for carbon monoxide (DLCO) (53-56).

The FEV₁ and DLCO are measurements best able to predict a patient’s ability to tolerate pulmonary resection (53). The FEV₁ serves as an indirect marker of the pulmonary reserve, and an FEV₁ <60% of its predicted value is associated with significantly increased postoperative pulmonary complications (57,58). Similarly, a DLCO of <60% predicted, measured by inhaling a small amount of carbon monoxide in one breath, is associated with a significantly increased risk of postoperative pulmonary complications and has been shown to be more predictive than the FEV₁ (59,60). The predicted postoperative (PPO) FEV₁ and DLCO can then be calculated by multiplying the preoperative value by the fraction of remaining lung after the resected portion has been subtracted out (61).

Predicting postoperative lung volume

There are several ways to calculate the PPO lung volume. The simplest involves counting the number of postoperative remaining pulmonary segments as a fraction of the number of preoperative functional segments. This fraction can be multiplied against the measured FEV₁ and DLCO to calculate the PPO FEV₁ and DLCO. While simplistic, this segment-counting method has been repeatedly validated (62,63).

Quantitative perfusion/ventilation scintigraphy and volumetric computed tomography (CT) scans are alternative methods for measuring the relative contribution of airflow or blood flow to the portion of the lung to be resected (63). Of these, perfusion scintigraphy is recommended by both the ACCP and JACS to determine the relative blood flow to the diseased lung when planning for a pneumonectomy (53,56). However, studies have demonstrated that the segment-counting is sufficiently accurate compared to V/Q scintigraphy when planning for a lobectomy (63). Furthermore, widespread CT scans can now also accurately predict the volumetric fraction of the lobe to be resected. As such, the ACCP and JACS guidelines recommend using the segment-counting method when planning for a lobectomy (53,56). In the event of borderline PPO lung volumes, the ERS/ESTS and BTS guidelines recommend performing lung volume assessment with either V/Q scintigraphy, volumetric CT, or magnetic resonance imaging (MRI) when preparing for a lobectomy (54,55).

Pulmonary assessment algorithm and exercise testing

According to the ACCP and JACS guidelines, if a patient has a PPO FEV₁ >60% predicted and a PPO DLCO >60% predicted, their risk of pulmonary complications is low and they can proceed to surgery without further testing (53,56).

Alternatively, if either a patient’s PPO FEV₁ or DLCO falls between 30% and 60% of predicted, the ACCP and JACS guidelines recommend that the patient undergo a simple exercise test, which may obviate the need for more expensive VO₂max testing (53,56). Both the stair climb test and shuttle walk test have been validated as acceptable simple exercise tests. Studies have found that climbing >22 m (about 3–4 fights of stairs) correlates with a VO₂max of >15 mL/kg/min, and has been associated with decreased complications after lung resection (64-67). Additionally, while some conflicting evidence exists, more recent studies have shown that performing a shuttle walk test for greater than 250 m correlates to a VO₂max >15 mL/kg/min, and that the ability to walk greater than 400 m is associated with decreased risk of complications after lung resection (68-70). If a patient cannot meet these benchmarks in either the stair climb or shuttle walk tests, they ought to undergo formal cardiopulmonary exercise testing (CPET). This is also recommended for any patients with a PPO FEV₁ or DLCO less than 30% predicted (53,56).

Formal CPET involves monitoring physiologic parameters while a patient exercises, usually on a treadmill or cycle. The level of activity is gradually increased over 8–15 minutes, allowing clinicians to monitor oxygen consumed relative to heart rate and work effort (71). This tests for myocardial demand ischemia, and is used to calculate the patient’s VO₂ max, a measure of a patient’s maximal oxygen consumption during activity (72,73). The association between the VO₂ max and the risk of postoperative complications after pulmonary resection is well-established (73-75). Per ACCP and JACS guidelines, patients with a VO₂max >20 mL/kg/min (greater than 75% predicted) have been shown to have sufficiently low rates of perioperative pulmonary complications after pulmonary resection, and may proceed to surgery (53). The 2010 BTS guidelines recommend a cutoff of >15 mL/kg/min as their threshold for safe surgery (55). However, patients with a VO₂max <10 mL/kg/min (less than 35% predicted) have been shown to be at very high risk of postoperative complications and perioperative death (76,77). As such, multiple guidelines recommend either a high-risk minimally-invasive sublobar resection or consideration for nonoperative management and/or palliative care (53,61). Per ACCP guidelines, patients are deemed to be medium-to-high risk if they have a VO₂max between 10 and 20 mL/kg/min (about 35–75% predicted), necessitating an informed discussion about the elevated risk of pulmonary resection (53).

Prophylactic interventions

Smoking cessation

For those patients with pulmonary comorbidities, both cigarette smoking cessation and preoperative pulmonary rehabilitation have been shown to help to reduce perioperative pulmonary risk. First among these is preoperative smoking cessation. There is no exact consensus regarding what duration of smoking cessation reduces perioperative risks (78,79). Despite this, many thoracic surgeons recommend quitting smoking about 1 to 2 months prior to resection. The trend seems to be that perioperative pulmonary complications decrease the longer the patient has been tobacco-free (80). However, new data suggest that by using VATS, ERAS protocols, and other modern practices, the risks of current perioperative smoking may be sufficiently mitigated, and argue that thoracic surgeons should not delay a potentially curative lung cancer resection while a patient attempts to quit smoking (81). Given this conflicting data, our group strongly recommends that patients cease smoking at the time of their initial preoperative visit, but we do not delay scheduling their pulmonary resection on account of smoking status. This approach typically allows patients 2–4 weeks of smoking cessation before surgery. However, our group does not necessarily delay surgery if the patient was unable to quit smoking during the preoperative period. Instead, we counsel the patient about the higher degree of risk involved, allowing us to make an informed decision with the patient. The subject of smoking cessation is explored in greater depth in a separate article in this series.

Preoperative pulmonary rehabilitation

There is modest evidence that enrolling patients in preoperative pulmonary rehabilitation can reduce perioperative complications. A multitude of recent studies have explored varying exercise regimens over different time intervals. Liu et al. demonstrated that an exercise program as short as 2 weeks demonstrated improvements in physical tests (e.g., an increase in a 6-minute walk distance) and an increased FEV₁. However, this did not translate into decreased postoperative complications or mortality (82). Licker et al. demonstrated that a high-intensity interval training regimen lasting between 3 and 4 weeks improved both VO₂max and the 6-minute walk distance. In this randomized controlled trial, the patients in the prehabilitation group had fewer pulmonary complications, which was attributed to reduced atelectasis in the prehabilitation group (83). Goldsmith et al. reported their prehabilitation experience with two groups of patients initially deemed to be prohibitively high-risk for surgery. Over a 4–6 week prehabilitation program, these groups sufficiently improved exercise capacity, “dyspnea scores,” and DLCO such that 43% and 55% of the patients in each group ultimately underwent pulmonary resection (84). A review published by Bibo et al. in 2021 summarized the results of several trials and meta-analyses, ultimately concluding that prehabilitation programs moderately improve patient exercise capacity, and are associated with a decrease in postoperative pulmonary complications and a reduction in overall hospital length of stay (85).

Limitations

A strength of this review is that it ties together both the cardiac and pulmonary assessment of patients preparing for a VATS resection for lung cancer, and incorporates guideline recommendations from multiple international authoritative bodies. However, there are some notable limitations of this review. As a narrative review, it is neither comprehensive nor systemic. Only guidelines published in English were summarized and used to generate recommendations. Given the breadth of the review, the authors generally provide only the key take-aways from notable trials, often forgoing in-depth analyses of each cited trial. Nevertheless, this review serves as a succinct overview of an essential component of workup of patients requiring a VATS pulmonary resection.

Conclusions

Patients diagnosed with early-stage, resectable lung cancer often have significant cardiac and pulmonary risk factors. While VATS pulmonary resections are increasingly safe, they are still considered high-risk surgeries, with significant potential for major cardiac and pulmonary complications in the perioperative period. As such, appropriate preoperative cardiac risk stratification, followed by pulmonary risk stratification, is essential to identify patients with elevated or high risk. This allows the thoracic surgeon to appropriately counsel the patient on their risks, facilitates any warranted testing, and potentially connects them to multidisciplinary subspecialists and care. This review provides an overview of the current state of both the preoperative cardiac and pulmonary assessment that all thoracic surgeons ought to be aware of. It compiles the most recent and relevant multinational guidelines into one document and offers supporting evidence from relevant clinical trials. This review, while not exhaustive, provides thoracic surgeons with a reference of the most up-to-date guidelines in one readable essay. Ultimately, this review may improve thoracic surgeons’ awareness of the most recent guidelines, thereby minimizing perioperative complications and maximizing the survival of patients with lung cancer.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Video-Assisted Thoracic Surgery for the series “Preoperative Planning and Assessment for VATS Lung Cancer Resection”. The article has undergone external peer review.

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://vats.amegroups.com/article/view/10.21037/vats-24-36/rc

Peer Review File: Available at https://vats.amegroups.com/article/view/10.21037/vats-24-36/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://vats.amegroups.com/article/view/10.21037/vats-24-36/coif). The series “Preoperative Planning and Assessment for VATS Lung Cancer Resection” was commissioned by the editorial office without any funding or sponsorship. G.D.T. served as the unpaid Guest Editor of the series and serves as an unpaid editorial board member of Video-Assisted Thoracic Surgery from February 2025 to December 2026. The authors have no other conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work and ensure that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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