Identifying risk factors for postoperative cardiovascular and respiratory complications after major oral cancer surgery

Major Perioperative Cardiac Risk Assessment: A Review for Cardio-Oncologists and Perioperative Physicians

The Revised Cardiac Risk Index (RCRI) and the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) preoperative risk assessment tools are the most widely used methods for quantifying the risk of major negative perioperative cardiac outcomes that a patient may face during and after noncardiac surgery. However, these tools were created to include as wide a range of surgical factors as possible; thus, some predictive accuracy is sacrificed when it comes to certain surgical subpopulations. In this review, we explore the various surgical oncology patient populations for whom these assessment tools can be reliably applied and for whom they demonstrate poor reliability.

Incidence and risk factors of postoperative pulmonary complications after oral cancer surgery with free flap reconstruction: A single center study

BACKGROUND

Postoperative pulmonary complications (PPCs) increase the risk of morbidity and mortality in patients who underwent oral cancer surgery with free flap reconstruction. The association between PPC and preoperative risk factors has been investigated; however, reports on intraoperative factors are limited. Therefore, we investigated PPC incidence and its associated preoperative and intraoperative risk factors in these patients.

METHODS

We retrospectively analyzed medical records of patients who underwent free flap reconstruction between 2009 and 2019. PPC was defined as presence of atelectasis, pneumonia, and respiratory failure based on radiological confirmation and clinical symptoms during hospitalization. Mortality, hospital stay, preoperative factors (including age and tumor stages), American Society of Anesthesiologists (ASA) classification, and intraoperative factors (including intraoperative fluids and medications) were recorded.

RESULTS

PPC incidence among the 993 patients included in this study was 25.8% (256 patients). Six patients with PPCs died; death was not observed among patients without PPCs (p < 0.001). Patients with PPCs had longer hospitalization than those without PPCs (30.3 vs 23.3 days; p < 0.001). Tumor stage (stage I: reference; stage II [OR]: 3.3, p = 0.019; stage III: 4.4, p = 0.002; stage IV: 4.8, p = 0.002), age (OR: 1.0; p < 0.001), and ASA grade >2 (OR: 1.4; p = 0.020) were independent risk factors of PPC; using labetalol was a borderline significant factor (OR: 1.4; p = 0.050).

CONCLUSION

The PPC incidence was 25.8% in patients undergoing oral cancer surgery with free flap reconstruction. Tumor stage, age, and ASA >2 were risk factors of developing PPC.

Risk Factors for Pulmonary Complications After Major Oral and Maxillofacial Surgery With Free Flap Reconstruction

Background Postoperative pulmonary complications (PPCs) are common and result in increased morbidity and mortality. A variable incidence of PPCs has been reported in patients who have undergone major oral and maxillofacial surgery with free flap reconstruction, which is one of the most extensive forms of head and neck cancer surgery, and perioperative risk factors for PPCs in these patients have not been fully elucidated. Furthermore, the ARISCAT (Assess Respiratory Risk in Surgical Patients in Catalonia) score and Gupta risk index have not been investigated in patients undergoing head and neck cancer surgery. This study aimed to identify perioperative risk factors for PPCs after major oral and maxillofacial surgery with free flap reconstruction. Methodology This was a single-center, retrospective cohort study of 118 patients who had undergone major oral and maxillofacial surgery with free flap reconstruction between 2009 and 2020. PPCs were defined as pneumonia, hypoxemia caused by atelectasis, pleural effusion, pulmonary embolism, pulmonary edema, bronchospasm, pneumothorax, and acute respiratory failure. Predictors of PPCs were identified in univariate and multiple Poisson regression analyses. Results The incidence of PPCs was 18.6% (22/118 patients). The most frequent PPC was pneumonia. No preoperative patient-related parameter was identified to predict PPCs. In univariate analysis, the only predictor was anesthesia time ≥1,140 minutes (odds ratio = 3.0, p = 0.036). Multivariable Poisson regression identified two independent predictors of PPCs, namely, anesthesia time ≥1,140 minutes (incidence rate ratio (IRR) = 2.18, 95% confidence interval (CI) = 1.1-4.3, p = 0.024) and a large amount of intraoperative fluid (IRR = 1.00018, 95% CI = 1.000018-1.000587, p = 0.037). Conclusions Patients undergoing major oral and maxillofacial surgery with free flap reconstruction are at high risk of PPCs. Longer anesthesia time and administering a large amount of fluid during surgery were significantly correlated with the risk of PPCs.

Comparison of surgical complications after curative surgery in patients with oral cavity squamous cell carcinoma and sarcopenia

BACKGROUND

The study aims to clarify the association of sarcopenia with perioperative and postoperative complications in oral cavity squamous cell carcinoma (OCSCC) patients undergoing curative surgery and to understand the reasons causing the poor oncologic outcomes for OCSCC.

METHODS

We conducted a propensity score matching study to investigate the association of perioperative and postoperative outcomes in OCSCC patients with sarcopenia and without sarcopenia. A retrospective analysis of a large national data set from the Taiwan Cancer Registry Database was conducted. At least two claims for patients with a principal diagnosis of sarcopenia within the 12-month preoperative period were defined as the criteria for sarcopenia diagnosis (ICD-10-CM code M62.84). Sarcopenia was diagnosed through the measurement of low muscle strength and low muscle mass by any one of the patient's attending orthopaedic physician, rehabilitation physician, family medicine specialist or geriatrician. A multivariate logistic regression model was used to calculate the perioperative, and postoperative major complications.

RESULTS

Our final cohort included 16 293 patients with OCSCC (10 862 and 5 431 in the sarcopenia and nonsarcopenia groups, respectively) who were eligible for further analysis. The sarcopenia group was 10.40% female and 89.60% male, and the nonsarcopenia group was 9.74% female and 90.26% male. The mean age ± standard deviation (SD) were 56.44 ± 11.14 and 56.22 ± 11.29 for sarcopenia and nonsarcopenia groups. OCSCC patients with sarcopenia undergoing curative surgery had a significantly higher blood transfusion rate and volume; longer intensive care unit (ICU) stay, and hospital stay; higher postoperative 30-day mortality (adjusted odds ratio [aOR]: 1.12, 95% confidence interval [CI] [1.07, 1.56]) and rates of pneumonia (aOR: 1.34, 95% CI [1.20, 1.50]), acute renal failure (aOR: 1.45, 95% CI [1.12, 1.87]) and septicaemia (aOR: 1.29, 95% CI [1.15, 1.45]); higher postoperative first-year mortality (aOR: 1.18, 95% CI [1.13, 1.51]) and rates of pneumonia (aOR: 1.43, 95% CI [1.30, 1.56]), acute myocardial infarction (aOR: 1.52, 95% CI [1.06, 2.18]) and septicaemia (aOR: 1.29, 95% CI [1.15, 1.45]).

CONCLUSIONS

OCSCC patients with sarcopenia might exhibit more perioperative and surgical complications than those without sarcopenia.

The comparative and added prognostic value of biomarkers to the Revised Cardiac Risk Index for preoperative prediction of major adverse cardiac events and all-cause mortality in patients who undergo noncardiac surgery

BACKGROUND

The Revised Cardiac Risk Index (RCRI) is a widely acknowledged prognostic model to estimate preoperatively the probability of developing in-hospital major adverse cardiac events (MACE) in patients undergoing noncardiac surgery. However, the RCRI does not always make accurate predictions, so various studies have investigated whether biomarkers added to or compared with the RCRI could improve this.

OBJECTIVES

Primary: To investigate the added predictive value of biomarkers to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery. Secondary: To investigate the prognostic value of biomarkers compared to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery. Tertiary: To investigate the prognostic value of other prediction models compared to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery.

SEARCH METHODS

We searched MEDLINE and Embase from 1 January 1999 (the year that the RCRI was published) until 25 June 2020. We also searched ISI Web of Science and SCOPUS for articles referring to the original RCRI development study in that period.

SELECTION CRITERIA

We included studies among adults who underwent noncardiac surgery, reporting on (external) validation of the RCRI and: - the addition of biomarker(s) to the RCRI; or - the comparison of the predictive accuracy of biomarker(s) to the RCRI; or - the comparison of the predictive accuracy of the RCRI to other models. Besides MACE, all other adverse outcomes were considered for inclusion.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form based on the CHARMS checklist. Independent pairs of authors screened references, extracted data and assessed risk of bias and concerns regarding applicability according to PROBAST. For biomarkers and prediction models that were added or compared to the RCRI in ≥ 3 different articles, we described study characteristics and findings in further detail. We did not apply GRADE as no guidance is available for prognostic model reviews.

MAIN RESULTS

We screened 3960 records and included 107 articles.   Over all objectives we rated risk of bias as high in ≥ 1 domain in 90% of included studies, particularly in the analysis domain. Statistical pooling or meta-analysis of reported results was impossible due to heterogeneity in various aspects: outcomes used, scale by which the biomarker was added/compared to the RCRI, prediction horizons and studied populations.  Added predictive value of biomarkers to the RCRI Fifty-one studies reported on the added value of biomarkers to the RCRI. Sixty-nine different predictors were identified derived from blood (29%), imaging (33%) or other sources (38%). Addition of NT-proBNP, troponin or their combination improved the RCRI for predicting MACE (median delta c-statistics: 0.08, 0.14 and 0.12 for NT-proBNP, troponin and their combination, respectively). The median total net reclassification index (NRI) was 0.16 and 0.74 after addition of troponin and NT-proBNP to the RCRI, respectively. Calibration was not reported. To predict myocardial infarction, the median delta c-statistic when NT-proBNP was added to the RCRI was 0.09, and 0.06 for prediction of all-cause mortality and MACE combined. For BNP and copeptin, data were not sufficient to provide results on their added predictive performance, for any of the outcomes. Comparison of the predictive value of biomarkers to the RCRI  Fifty-one studies assessed the predictive performance of biomarkers alone compared to the RCRI. We identified 60 unique predictors derived from blood (38%), imaging (30%) or other sources, such as the American Society of Anesthesiologists (ASA) classification (32%). Predictions were similar between the ASA classification and the RCRI for all studied outcomes. In studies different from those identified in objective 1, the median delta c-statistic was 0.15 and 0.12 in favour of  BNP and NT-proBNP alone, respectively, when compared to the RCRI, for the prediction of MACE. For C-reactive protein, the predictive performance was similar to the RCRI. For other biomarkers and outcomes, data were insufficient to provide summary results. One study reported on calibration and none on reclassification. Comparison of the predictive value of other prognostic models to the RCRI   Fifty-two articles compared the predictive ability of the RCRI to other prognostic models. Of these, 42% developed a new prediction model, 22% updated the RCRI, or another prediction model, and 37% validated an existing prediction model. None of the other prediction models showed better performance in predicting MACE than the RCRI. To predict myocardial infarction and cardiac arrest, ACS-NSQIP-MICA had a higher median delta c-statistic of 0.11 compared to the RCRI. To predict all-cause mortality, the median delta c-statistic was 0.15 higher in favour of ACS-NSQIP-SRS compared to the RCRI. Predictive performance was not better for CHADS₂, CHA₂DS₂-VASc, R₂CHADS₂, Goldman index, Detsky index or VSG-CRI compared to the RCRI for any of the outcomes. Calibration and reclassification were reported in only one and three studies, respectively.

AUTHORS' CONCLUSIONS

Studies included in this review suggest that the predictive performance of the RCRI in predicting MACE is improved when NT-proBNP, troponin or their combination are added. Other studies indicate that BNP and NT-proBNP, when used in isolation, may even have a higher discriminative performance than the RCRI. There was insufficient evidence of a difference between the predictive accuracy of the RCRI and other prediction models in predicting MACE. However, ACS-NSQIP-MICA and ACS-NSQIP-SRS outperformed the RCRI in predicting myocardial infarction and cardiac arrest combined, and all-cause mortality, respectively. Nevertheless, the results cannot be interpreted as conclusive due to high risks of bias in a majority of papers, and pooling was impossible due to heterogeneity in outcomes, prediction horizons, biomarkers and studied populations. Future research on the added prognostic value of biomarkers to existing prediction models should focus on biomarkers with good predictive accuracy in other settings (e.g. diagnosis of myocardial infarction) and identification of biomarkers from omics data. They should be compared to novel biomarkers with so far insufficient evidence compared to established ones, including NT-proBNP or troponins. Adherence to recent guidance for prediction model studies (e.g. TRIPOD; PROBAST) and use of standardised outcome definitions in primary studies is highly recommended to facilitate systematic review and meta-analyses in the future.

Postoperative pulmonary complications following major head and neck cancer surgery

The primary aim of this observational study was to describe the incidence of postoperative pulmonary complications (PPCs) in 60 consecutive, surgically treated head and neck cancer patients requiring free flap reconstruction and tracheostomy, using both a prospective and a retrospective outcome measure. Secondary aims were to identify risk factors for PPC development, explore the effects of PPC on outcomes, and describe the provision of postoperative physiotherapy in this population. Postoperative pulmonary complications occurred in nine (15%) patients based on the Melbourne Group Scale and 27 (45%) patients based on Health Information Service coding data. The occurrence of a PPC was not statistically correlated with age, smoking history, comorbidities, operative time, or type of resection or free flap. Patients who developed a PPC, compared to those who did not, had a higher preoperative body mass index (P=0.022) and were more likely to be sat out of bed earlier post-surgery (P=0.038). Overall, patients required a median of 9.0 (interquartile range 7.0-11.0) physiotherapy sessions. Patients developing a PPC required significantly more physiotherapy sessions (P=0.007) and additional days of supplemental oxygen (P=0.022) as compared to those without a PPC, despite a similar hospital length of stay. In future, targeted physiotherapy interventions may reduce PPCs in this population.

Immediate Implant-Based Breast Reconstruction with Acellular Dermal Matrix: A Comparison of Sterile and Aseptic AlloDerm in 2039 Consecutive Cases

BACKGROUND

Sterile ready-to-use acellular dermal matrix, introduced as an alternative to aseptic freeze-dried acellular dermal matrix for implant-based breast reconstruction, has been investigated in a limited number of studies. This study compared outcomes in implant-based breast reconstruction with ready-to-use and freeze-dried acellular dermal matrix.

METHODS

The authors analyzed patients undergoing implant-based breast reconstruction with either freeze-dried or ready-to-use acellular dermal matrix, including demographics, clinical variables, and outcomes. An a priori power analysis was performed and logistic regression modeling was used to quantify the effect of acellular dermal matrix on outcomes while controlling for potential confounders.

RESULTS

A total of 1285 consecutive patients undergoing 2039 immediate prosthetic breast reconstructions constituted the population: 612 (n = 910 breasts) with freeze-dried matrix and 673 (n = 1129 breasts) with ready-to-use acellular dermal matrix. The freeze-dried matrix cohort had a significantly higher rate of explantation compared with the ready-to-use matrix cohort (18.0 percent versus 12.0 percent; p = 0.0036), but surgical-site infection, wound dehiscence, mastectomy flap necrosis, seroma, and hematoma did not differ significantly between groups. On multivariate regression, patients undergoing reconstruction with freeze-dried matrix, compared to ready-to-use matrix, did not have higher odds of experiencing surgical-site infections (OR, 1.064; p = 0.7455), but did have higher odds of explantation (OR, 1.570; p = 0.0161). Tobacco use (OR, 2.809; p = 0.0002) and body mass index (OR, 1.054; p < 0.0001) were also independent predictors of explantation.

CONCLUSION

Immediate implant-based breast reconstruction with sterile ready-to-use acellular dermal matrix has a comparable overall safety profile and a lower rate of prosthetic explantations compared with aseptic freeze-dried acellular dermal matrix.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Perioperative risk factors for postoperative pneumonia after major oral cancer surgery: A retrospective analysis of 331 cases

Objective

Postoperative pneumonia (POP) is common and results in prolonged hospital stays, higher costs, increased morbidity and mortality. However, data on the incidence and risk factors of POP after oral and maxillofacial surgery are rare. This study aims to identify perioperative risk factors for POP after major oral cancer (OC) surgery.

Methods

Perioperative data and patient records of 331 consecutive subjects were analyzed in the period of April 2014 to March 2016. We individually traced each OC patient for a period to discharge from the hospital or 45 days after surgery, whichever occur later.

Results

The incidence of POP after major OC surgery with free flap construction or major OC surgery was 11.6% or 4.5%, respectively. Patient-related risk factors for POP were male sex, T stage, N stage, clinical stage and preoperative serum albumin level. Among the investigated procedure-related variables, incision grade, mandibulectomy, free flap reconstruction, tracheotomy, intraoperative blood loss, and the length of the operation were shown to be associated with the development of POP. Postoperative hospital stay was also significantly related to increased incidence of POP. Using a multivariable logistic regression model, we identified male sex, preoperative serum albumin level, operation time and postoperative hospital stay as independent risk factors for POP.

Conclusion

Several perioperative risk factors can be identified that are associated with POP. At-risk oral cancer patients should be subjected to intensified postoperative pulmonary care.

Perioperative risk factors for postoperative pulmonary complications after major oral and maxillofacial surgery with microvascular reconstruction: A retrospective analysis of 648 cases

BACKGROUND

Postoperative pulmonary complications (PPCs) are common and result in prolonged hospital stays, higher costs and increased mortality. However, data on the incidence and predictors of PPCs after major oral and maxillofacial surgery with microvascular reconstruction are rare. This retrospective analysis identifies perioperative risk factors for postoperative pulmonary complications (PPCs) after major oral and maxillofacial surgery with microvascular reconstruction.

METHODS

Perioperative data and patient records of 648 subjects were analyzed in the period of June 2007 to May 2013. PPCs were defined as pneumonia, atelectasis, pleural effusions, pulmonary embolism, pulmonary oedema, pneumothorax or respiratory failure.

RESULTS

18.8% of all patients developed PPCs. Patient-related risk factors for PPCs were male sex, advanced age, smoking, alcohol abuse, a body mass index >30, American Society of Anaesthesiologists grade higher than 2, pre-existent pulmonary diseases and preoperative antihypertensive medication. Among the investigated procedure-related variables, the length of the operation, the amount of fluid administration and blood transfusion and an impaired oxygenation index during surgery were shown to be associated with the development of PPCs. Using a multivariable logistic regression model, we identified a body mass index >30, American Society of Anaesthesiologists grade higher than 2 and alcohol abuse as independent risk factors for PPCs.

CONCLUSIONS

Several perioperative factors can be identified that are associated with the development of PPCs. Patients having one or more of these conditions should be subjected to intensified postoperative pulmonary care.

Proposed research plan for the derivation of a new Cardiac Risk Index

The Revised Cardiac Risk Index (RCRI) was incorporated into the American College of Cardiology/American Heart Association (ACC/AHA) recommendations for the preoperative evaluation of the cardiac patient for noncardiac surgery. The purpose of this review was to analyze studies on cardiovascular clinical risk prediction that had used the previous "standard best" model, the RCRI, as a comparator. This review aims to determine whether modification of the current risk factors or adoption of other risk factors or other risk indices would improve upon the discrimination of cardiac risk prediction when compared with the RCRI. This is necessary because recent risk prediction models have shown better discrimination for major adverse cardiac events, and the pre-eminence of the RCRI is now in question. There is now a need for a new "best standard" cardiovascular risk prediction model to supersede the RCRI. This is desirable because it would: (1) allow for a global standard of cardiovascular risk assessment; (2) provide a standard comparator in all risk prediction research; (3) result in comparable data collection; and (4) allow for individual patient data meta-analyses. This should lead to continued progress in cardiovascular clinical risk prediction. A review of the current evidence suggests that to improve the preoperative clinical risk stratification for adverse cardiac events, a new risk stratification model be built that maintains the clinical risk factors identified in the RCRI, with the following modifications: (1) additional glomerular filtration rate cut points (as opposed to a single creatinine cut point); (2) age; (3) a history of peripheral vascular disease; (4) functional capacity; and (5) a specific surgical procedural category. One would expect a substantial improvement in the discrimination of the RCRI with this approach. Although most noncardiac surgeries will benefit from a standard "generic" cardiovascular risk prediction model, there are data to suggest that patients with human immunodeficiency virus disease who are undergoing vascular surgery may benefit from specific cardiovascular risk prediction models.

Is benchmarking possible in audit of early outcomes after operations for head and neck cancer?

There is a need for a validated means of adjusting for case mix in morbidity audits of patients with cancer of the head and neck. To address this, we did a multicentre audit of 3 U.K. NHS cancer networks that treat patients with head and neck cancer, to compare the incidence of early adverse postoperative outcomes and to develop a means of adjusting for case mix. We did a retrospective and prospective audit of the case notes of 901 consecutive patients who had 1034 operations for squamous cell carcinoma (SCC) of the head and neck under general anaesthesia at 3 NHS hospitals. Analysis of raw data showed postoperative 30-day mortality (n=17) to be consistent between sites (1.7%-1.9%) but 30-day complication rates varied more (34%-49%). Logistic regression models predicting morbidity discriminated well (area under the curve 0.74-0.76). Adjusted morbidity rates for the 3 units were compared on a funnel plot with 95% and 99% confidence intervals to account for random variation. It is possible to benchmark surgical performance by focusing on early postoperative outcomes in head and neck surgery. Morbidity is common and usually has a considerable impact on recovery, bed occupancy, cost, and the patient's perception of the quality of care.

Gauze padding: a simple technique to delineate small oral cavity tumors

BACKGROUND AND PURPOSE

Small oral cavity tumors are an imaging challenge. Intimate apposition of vestibular oral mucosa to the alveolar mucosa makes tumor assessment difficult. In CT imaging, the "puffed cheek" method has been used to separate surfaces, though this is not feasible with long MR imaging sequences. We implemented placement of 2 × 2 inch (6.45 cm) gauze into the oral vestibule before the MR imaging examination, to determine whether this might improve tumor visualization.

MATERIALS AND METHODS

MR imaging examinations of all T1 oral malignant tumors treated at University of California, San Francisco, by the Oral and Maxillofacial Department were reviewed by 2 neuroradiologists. Nine patients were included in the final analysis. Six patients were imaged by using a standard protocol. Three patients were imaged with gauze placement. The radiologists evaluated the MR images, assessing whether they could see the tumor and then fully delineate it and its thickness.

RESULTS

Fisher exact analysis was performed on questions 1, 2, and 4 with the following results: P value = .048, Can you see the tumor? P value = .012, Can you fully delineate? P value of .012, How confident are you? MR imaging examinations with gauze clearly delineated the tumor with the tumor thickness measurable. MR imaging examinations without gauze did not clearly show the tumor or its thickness. Confidence of interpretation of the findings was also increased when gauze was used.

CONCLUSIONS

A 2 × 2 inch (6.45 cm) rolled gauze in the oral vestibule significantly improved tumor localization and delineation at MR imaging. This technique is simple and provides superior preoperative imaging evaluation and treatment planning of small oral cavity tumors.