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Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database
Journal Pre-proof Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database. Benjamin Clapp, MD, Evan Liggett, MD, Cong Phan, Christopher Dodoo, MS, Isaac Lee, MD, Michael Cutshall, MD, Alan Tyroch, MD. PII:
S1550-7289(20)30046-0
DOI:
https://doi.org/10.1016/j.soard.2020.01.026
Reference:
SOARD 4044
To appear in:
Surgery for Obesity and Related Diseases
Received Date: 30 September 2019 Revised Date:
26 November 2019
Accepted Date: 25 January 2020
Please cite this article as: Clapp B, Liggett E, Phan C, Dodoo C, Lee I, Cutshall M, Tyroch A, Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database., Surgery for Obesity and Related Diseases (2020), doi: https://doi.org/10.1016/j.soard.2020.01.026. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.
Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database.
Benjamin Clapp MD, Evan Liggett MD, Cong Phan, Christopher Dodoo MS, Isaac Lee MD, Michael Cutshall MD, Alan Tyroch MD.
All authors are affiliated with Texas Tech Health Sciences Center Paul Foster School of Medicine
There are no funding sources for this work.
Short title: Conversions MBSAQIP
Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database.
Benjamin Clapp MD, Evan Liggett MD, Cong Phan, Christopher Dodoo MS, Isaac Lee MD, Michael Cutshall MD, Alan Tyroch MD.
Background: The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database tracks patients, techniques and outcomes for 30 days. The overwhelming majority of cases reported are performed using a laparoscopic technique. Bariatric surgeons rarely have to convert from laparoscopy to open surgery. Objectives: We examined the MBSAQIP to determine the characteristics of patients who underwent conversion and evaluated their short-term outcomes. Settings: University program in the United States and nationwide clinical database. Methods: The MBSAQIP Public Use File for 2017 was examined for primary bariatric operations. We identified patients who underwent a sleeve gastrectomy (SG) or gastric bypass (LRYGB) using a minimally invasive technique. We identified patients who underwent conversion to another operative technique or were converted to open surgery and analyzed preoperative characteristics and postoperative complication rates. Relative risks (RR) were calculated for complications. P was significant at < 0.05. Results: There were 186,962 patients in the entire cohort. 609 patients underwent conversion from the original surgical approach to either open surgery (n=457) or to another technique (n=152). Patients with preoperative oxygen dependency, poor functional status, previous foregut/obesity surgery, preoperative renal insufficiency and anticoagulation were more likely to
undergo conversion. Patients who underwent conversion to the open approach had longer operative times (191 vs 86.6 minutes [P<0.00]) and longer time to discharge (6.2 vs 1.6 days [P<0.001]). The RR of death was 18.2 (95%CI 8.7-37.6, P<0.001) for procedures converted to open. The RR of sepsis was 10.1 (95%CI 4.2-24.2, P<0.001) and the RR for all complications was increased throughout for patients undergoing conversion. Conclusions: Patients in the MBSAQIP database that undergo conversion to the open surgical approach are at a greatly increased risk for death and complications.
Key words: conversion to open surgery, conversions, MBSAQIP, bariatric surgery
Introduction In the last few decades, laparoscopy has largely influenced surgical practice and became the standard of care for general surgery abdominal operations and bariatric procedures. Overall, complication rates associated with laparoscopic surgery remains low [1]. Laparoscopic metabolic and bariatric surgery (MBS) has become the normal technique in the United States. The laparoscopic approach is the most common technique employed, but conversion to open laparotomy is still sometimes necessary. It is rare today to perform open MBS, even for revisions. In fact, when compared to other disciplines in general surgery, MBS has the lowest conversion rate [2]. It is now expected that bariatric surgery will take place laparoscopically, with either a traditional laparoscopic technique or a robotic assisted laparoscopic technique. However, surgeons still recognize the need to fall back on open surgery occasionally. This is usually not seen as a failure but instead an exercise in good judgment. Reasons for converting to open range from such factors as bleeding, lack of abdominal wall compliance, or failure to progress. Conversions can be classified into two separate categories: reactive conversion and preemptive conversion. Reactive conversion occurs as a result of an intraoperative complication, whereas preemptive conversion is one that is undertaken to avoid one [3]. When the surgeon determines it is dangerous, futile or foolish to continue using a laparoscopic technique, a change to another approach makes sense. The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database collects 30-day outcomes on patients, including preoperative patient characteristics, operative details and postoperative outcomes. We proposed examining the Participant Use Data File (PUF) to determine the characteristics of the patients who underwent a conversion from laparoscopy to open. We also examined robotic to laparoscopic or open cases as
well as hand assisted. Our outcomes of interest were patient characteristics, operative details and postoperative outcomes of patients that underwent conversion.
Methods The MBSAQIP PUF for 2017 was used to analyze data for primary bariatric operations and revisions. The MBSAQIP PUF is a bariatric surgery–specific clinical data set, which contains approximately 200 variables including preoperative patient characteristics, procedure details, as well as details on complications, reoperations, readmissions, or interventions within 30 days. The MBSAQIP-PUF does not identify hospitals or individual healthcare providers. Data are collected prospectively and entered into the database by trained abstractors at each site. Data are based on standardized definitions for preoperative, intraoperative, and postoperative variables specific to bariatric surgery. Extensive efforts are made to ensure quality and reliability of data across sites by regular auditing and training of data abstractors. We identified patients who underwent a sleeve gastrectomy or gastric bypass using a minimally invasive technique. We then identified patients who underwent conversion to another operative technique or were converted to open surgery and examined preoperative characteristics and postoperative complication rates. Relative risks (RR) were calculated for complications. P was significant at < 0.05. To reflect a typical patient population, inclusion was restricted to patients with a body mass index (BMI) of 35 to 70 kg/m2. We used the fields SURGICAL APPROACH, APPROACH_CONVERTED, and CONVERISON. APPROACH_CONVERTED has a yes/no answer, the other two have the following options: single Incision robotic-assisted, conventional laparoscopic (thoracoscopic), laparoscopic assisted (thoracoscopic assisted) and hand-assisted.
Exclusion criteria included patients who underwent hiatal hernia repair, emergency procedures, or unrelated concurrent procedures, such as hysterectomy. We also excluded patients who were >80 years old, those requiring dialysis preoperatively, and American Society of Anesthesiology (ASA) Class 5 (moribund). Additionally, 30-day readmission data were extracted from the separate readmission file by matching the unique case identification numbers for each patient included in the study. Two primary composite outcomes of interest included patient and operative characteristics of those that required conversion to open and outcomes. All-cause morbidity was comprised of 30-day mortality, unplanned admission to intensive care unit, readmissions, reoperation, reintervention, surgical site infection (SSI - composite of superficial and deep SSI), organ/space SSI, wound disruption, deep vein thrombosis (vein thrombosis requiring therapy), pulmonary embolism, postoperative pneumonia, ventilator use for>48 hours, intraoperative or postoperative myocardial infarction, intraoperative or postoperative cardiac arrest requiring cardiopulmonary resuscitation, stroke or cerebrovascular event, coma lasting>24 hours, unplanned intubation, acute renal failure, progressive renal insufficiency, postoperative urinary tract infection, intraoperative or postoperative transfusion performed within 72 hours of surgery, peripheral nerve injury, postoperative sepsis, and postoperative septic shock. Secondary outcomes of interest included operative time, length of hospital stay, 30-day rates of readmission, reoperation and reintervention. This study was exempt from institutional review board approval, as data were publicly available in a de-identified manner. The hospitals participating in the MBSAQIP are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.
Statistical analysis Quantitative variables were summarized using mean and standard deviations (SD). Categorical variables were summarized using frequencies and proportions. To access the baseline differences in patient characteristics, operation characteristics and preoperative comorbidities, the student's t-test and chi-squared test were used. Unadjusted and adjusted factors affecting postoperative complications were assessed using generalized linear models with a link log and family Poisson, and logistic regression models. These measures were reported as prevalence ratio (PR) and odds ratio (OR), together with their 95% confidence interval (CI). P values of less than 5 % were considered statistically significant. We generated propensity scores for conversion [to open] or no conversions using a logistic regression model adjusted for known baseline characteristics, operation information and preoperative comorbidities. A backward -stepwise selection with an entry level of 0.05 was used to obtain the significant variables. A propensity score between 0 – 1 was then generated for each patient using the significant variables. Based on the obtained propensity scores, two evenly matched groups were generated based on conversion status using a matching algorithm with the common caliper set at 0.005. This resulted in 652 (326 in each group). The matched cohort was further assessed for balance by assessing differences across all the potential confounders (refer to supplementary tables 1 and 2). Further risk adjustment checks were done using multivariate analysis with adjustments done for covariates that remained unbalanced between the 2 matched groups. All analyses were carried out using STATA v.15.
Results
There were 186,962 patients in the entire cohort for 2017. Only 609 patients underwent conversion from the original surgical technique to either open surgery (n=457) or to another technique (n=152). This gives a conversion rate of 0.3% from laparoscopic to open surgery. The highest rate of conversion by case was the LRYGB at 0.2%. SG were converted at a rate of 0.05%. There were 112 (0.06%) cases of laparoscopic converted to “other” and for robot conversions to “other” there were 40 cases (0.28%). For conversion to open, there were 435 (0.25%) of laparoscopic to open and 22 (0.15%) for robotic to open. But in the propensity matched analysis there was no difference between laparoscopic vs robotic (50.2% vs 45.7%, P = 0.6). Table 1 summarizes the baseline characteristics of the total study population and the conversion to open group. Patients converted to open surgery had higher rates of oxygen dependency, poor functional status, previous foregut/obesity surgery, preoperative renal insufficiency and were chronically anticoagulated. Patients undergoing conversion to open had longer operative times (87 vs 191 minutes, P < 0.001), longer time to discharge (1.6 vs 6.2 days, P < 0.001). When the one approach was converted to other than open (i.e. robot to laparoscopic), the operative time increased to 160 minutes and length of stay was extended to 2.4 days. Table 2 summarizes postoperative complications. There were 161 deaths in the total cohort for a rate of 0.09%, but the mortality rate of patients converted to open was much higher at 1.53% (P < 0.001). There were statistically significant differences across the board in complications in patients that were converted to open, but clinically significant complications were admission to ICU, SSI, and transfusion. There were also higher rates of readmission, reintervention and revision within 30 days. Table 3 demonstrates the adjusted associations for postoperative morbidity and mortality. The OR of death was 7.52 (95%CI 2.84-19.9, P < 0.001). The OR for overall morbidity was
11.5 (95%CI 9.0-14.8, P < 0.001). The risks of readmission, reintervention and reoperation were increased by at least four-fold. After propensity matched scoring, the result trends remain the same, but with smaller effect sizes (Table 4).
Discussion This is the largest study to date examining conversion from the laparoscopic to the open technique in bariatric surgery. The most significant finding of our paper is the lack of conversions. US and Canadian surgeons have been able to drop the conversion rate of very complex laparoscopic procedures to a rate of 0.2%. This is an astoundingly low rate that has improved from previous years. Our main results show that when propensity matched analysis is performed, converted patients have longer operative times, longer length of stay and higher rates of death and morbidity. The MBSAQIP database does not have the granularity to determine if procedures were aborted or switched intraoperatively to another procedure, i.e. SG to LRYGB. We may be missing these cases as a “conversion” as this situation has no method of recording in the PUF. Nguyen et al used the University Health System Consortium database to examine postoperative complications and in a sample of almost 54,000 patients undergoing bariatric surgery from 2008-2012 and found a conversion rate of 0.89% [2]. When this data was broken down by the type of bariatric surgery, the rate for conversion was greatest for LRYGB (2.5%), followed by laparoscopic SG (0.11%) and laparoscopic adjustable gastric banding (0.07%). The current reported rates for the 2017 MBSAQIP data show an improvement over these already low numbers. A recent study using the MBSAQIP data comparing robotic to laparoscopic surgery showed higher conversion rates in the robotic group with rates either for SG (0.53% vs. 0.12%; P <0.001) and for RYGB (0.57% vs. 0.26%; P =0.01). This was data from 2015-2016 [4]. The
LRGYB remains the most commonly converted operation. Conversion rates are so low that a paper was published in Obesity Surgery in 2016 reviewing the technique of open gastric bypass [5]. Other interesting findings were the preoperative characteristics of patients undergoing conversion to open surgery. We found patients converted to open surgery had higher rates of oxygen dependency, poor functional status, previous foregut/obesity surgery, preoperative renal insufficiency and were chronically anticoagulated. This likely indicates that sicker patients and patients with previous foregut/obesity surgery are more difficult technically. The reported rates of intraoperative conversion from laparoscopic to open surgery vary greatly depending on the type of procedure performed. Conversion rates have been reported as 2.6%-10% in cholecystectomy; 29.8% in diverticulitis surgery; 21% in IBD [3] and 4.2% in gastric bypass [6]. The most common reasons for conversion are severe adhesions caused by tissue inflammation [7], inability to correctly identify anatomy [8], and BMI (and waist circumference) [9]. Conversions can be classified according to perceived cause. Yang et al. described limitations of the disease process (adhesions, phlegmon etc.), technical problems (unclear anatomy), and intraoperative complications (bleeding, bowel injury, ureteral damage and splenic injury) [3]. Lengyel et al. used the NSQIP database to look at reasons for conversion in cholecystectomy. They had a 5.8% conversion to open rate, and the majority of those seemed to be converted early, perhaps from immediate assessment by the surgeon of perceived difficulty [10]. For the treatment of acute cholecystitis, lower surgeon volume was also a predictor of the need for open conversion and prolonged length of hospital stay [11]. The MBSAQIP can elucidate patient characteristics but does not have the granularity to describe reasons for conversion to the open technique. Our paper shows an extremely low rate of conversion to open,
but we cannot make any statements as to the cause of opening. We initially thought we would at least be able to tell bleeding complications as a reason, but there was a non-significant difference between the groups. We examined some operative characteristics such as blood loss but this is listed as “transfusion intra-op/post-op (72 hours of surgery start time).” This does not tell us if the blood loss was the cause of the conversion vs a consequence of conversion. We also can draw some conclusions about adhesions as patients with previous foregut/obesity surgery had higher risks of conversion. This conceivably could be related to adhesions from previous operations. This is a lack of granularity of the MBSAQIP data that all researchers using the PUF struggle with. Although there is no way to tease out the reasons for conversion, when they occurred, they greatly increased the risks of death and complications. Surgeons may consider this when making an intraoperative decision to perform and elective conversion, but they still need to be ready to convert in emergencies situations such as uncontrolled bleeding. The most common complications in the aforementioned studies were prolonged ileus, pneumonia and SSI. In a previous study, the patients in the conversion group were also more likely to experience a longer time to regular diet (5-6 vs 4.4 days), longer hospital stay (7.1-8.1 vs 5.3 days), longer time to flatus (4.76-5.4 vs 3.2 days), and a higher postoperative complication rate (27% to 50% vs 11.7%) [3]. This is similar to our results with the greatly increased RR of sepsis, infectious complications and death.
Strengths and limitations Administrative databases are inherently subject to reporting bias if there are errors in the diagnosis or procedure codes that are used. However, for the MBSAQIP database, extensive
efforts are made to ensure quality and reliability of data across sites by regular auditing and training of data abstractors. Being able to pool this highly reliable data means we can feel confident that our results truly reflect the state of surgery at those centers that report the data. That being said, we are missing data from surgeries performed at non-accredited centers. Data reported in the MBSAQIP may be significantly different from the non-accredited centers and therefore not generalizable. Additionally, the PUF is also de-identified for HIPAA purposes, making it impossible to determine the impact of surgeon experience on conversion rates. More experienced laparoscopic surgeons may have much different rates of conversion and postoperative complications than less-experienced surgeons, but there is simply not a way for us to tease that out as the de-identification prevents such granularity. Another limitation is that this is a retrospective study and it is subject to the disadvantages of such studies, including the inability to determine causation, only association.
Conclusions Patients undergoing MBS today are at an extremely low risk of conversion from laparoscopy to an open technique. Patients in the MBSAQIP database that did undergo conversion to the open surgical technique are at a greatly increased risk for death and complications.
Conflict of interest statement: none of the authors have a conflict of interest.
Table 1. Summary descriptive of baseline characteristics in entire cohort and by conversions. Table 2. Summary descriptive of postoperative complications. Table 3. Unadjusted associations for morbidity and mortality. Table 4. Adjusted analysis on propensity matched cohort
References
1. Perugini RA, Callery MP. Complications of laparoscopic surgery. In: Holzheimer RG, Mannick JA, editors. Surgical Treatment: Evidence-Based and Problem-Oriented. Munich: Zuckschwerdt; 2001. 2. Nguyen NT, Nguyen B, Shih A, Smith B, Hohmann S. Use of laparoscopy in general surgical operations at academic centers. Surg Obes Relat Dis. 2013;9(1):15-20. doi: 10.1016/j.soard.2012.07.002. Epub 2012 Jul 16. 3. Yang C, Wexner SD, Safar B, et al. Conversion in laparoscopic surgery: does intraoperative complication influence outcome? Surg Endosc. 2009;23(11):2454-2458. doi:10.1007/s00464009-0414-6. 4. Sebastian R, Howell MH, Chang KH, Adrales G, Magnuson T, Schweitzer M, Nguyen H. Robot-assisted versus laparoscopic Roux-en-Y gastric bypass and sleeve gastrectomy: a propensity score-matched comparative analysis using the 2015-2016 MBSAQIP database. Surg Endosc. 2019;33(5):1600-1612. doi: 10.1007/s00464-018-6422-7. Epub 2018 Sep 17. 5. Jones, KB. When and how to "open" in laparoscopic or robotic surgery. Obes Surg. 2016;26(4):891-5. doi: 10.1007/s11695-016-2095-2. 6. Schwartz ML, Drew RL, Chazin-Caldie M. Laparoscopic Roux-en-Y gastric bypass: preoperative determinants of prolonged operative times, conversion to open gastric bypasses, and postoperative complications. Obes Surg. 2003;13(5):734-738. doi:10.1381/096089203322509309.
7. Genc V, Sulaimanov M, Cipe G, et al. What necessitates the conversion to open cholecystectomy? A retrospective analysis of 5164 consecutive laparoscopic operations. Clinics. 2011;66(3):417-420. doi:10.1590/s1807-59322011000300009. 8. Bingener-Casey J. Reasons for conversion from laparoscopic to open cholecystectomy; a 10year review. J Gastrointest Surg. 2002;6(6):800-805. doi:10.1016/s1091-255x(02)00064-1. 9. Schwartz M, Drew R, Chazin-Caldie M. Factors determining conversion from laparoscopic to open Roux-en-Y gastric bypass. Obes Surg. 2004;14(9):1193-1197. doi:10.1381/0960892042386887. 10. Lengyel B, Azagury D, Varban O, Panizales M, Steinberg J, Brooks DC, Ashley SW, Tavakkolizadeh A. Laparoscopic cholecystectomy after a quarter century: why do we still convert? Surg Endosc. 2012;26(2):508-13. doi: 10.1007/s00464-011-1909-5. Epub 2011 Sep 23. 11. Csikesz N, Singla A, Murphy M, Tseng J, Shah S. Surgeon volume metrics in laparoscopic cholecystectomy. Dig Dis Sci. 2009;55(8):2398-2405. doi:10.1007/s10620-009-1035-6.
Table 1: Summary descriptive of baseline characteristics in entire cohort, and by conversions Converted? Factor Cohort No To Open N 186962 186353 457 DEMOGRAPHICS Age, mean (SD) BMI, mean (SD) Albumin Lab Value, mean (SD) Hematocrit Lab Value, mean (SD) Operation Length (minutes), mean (SD) Days to discharge, mean (SD) Sex Female Male Race Black Others Unknown White Hispanic Ethnicity No Unknown Yes Preoperative comorbidities Preoperative diabetes mellitus Insulin No Non-Insulin Preoperative hyperlipidemia
To Others 152
p-value
PR (95% CI)*
P-value
45.2 (12.0) 44.5 (7.3) 4.0 (0.4) 40.7 (3.9) 87.0 (52.0)
45.2 (12.0) 44.5 (7.2) 4.0 (0.4) 40.7 (3.9) 86.6 (51.6)
51.5 (10.7) 43.4 (8.8) 3.9 (0.5) 39.8 (4.9) 191.2 (96.2)
45.9 (11.2) 47.4 (8.5) 3.9 (0.4) 40.8 (4.0) 160.9 (75.2)
<0.001 <0.001 <0.001 <0.001 <0.001
1.04 (1.04, 1.05) 0.98 (0.96, 1) 0.37 (0.29, 0.46) 0.95 (0.93, 0.97) 1.01 (1.01, 1.01)
<0.001 0.013 <0.001 <0.001 <0.001
1.6 (1.5)
1.6 (1.4)
6.2 (7.5)
2.4 (3.3)
<0.001 0.22
1.11 (1.1, 1.12)
<0.001
150610 (80.6%) 36352 (19.4%)
150136 (80.6%) 36217 (19.4%)
354 (77.5%) 103 (22.5%)
120 (78.9%) 32 (21.1%)
Reference 1.21 (0.97, 1.5)
0.094
Reference 1.95 (1.01, 3.76) 0.57 (0.35, 0.92) 1.09 (0.85, 1.39)
0.046 0.022 0.51
Reference 0.91 (0.65, 1.26) 0.66 (0.48, 0.92)
0.55 0.014
Reference 0.77 (0.57, 1.05) 0.79 (0.55, 1.14)
0.104 0.20
0.018 33124 (17.7%) 2178 (1.2%) 15655 (8.4%) 136005 (72.7%)
33025 (17.7%) 2167 (1.2%) 15623 (8.4%) 135538 (72.7%)
78 (17.1%) 10 (2.2%) 21 (4.6%) 348 (76.1%)
21 (13.8%) 1 (0.7%) 11 (7.2%) 119 (78.3%)
147311 (78.8%) 16751 (9.0%) 22900 (12.2%)
146809 (78.8%) 16692 (9.0%) 22852 (12.3%)
379 (82.9%) 39 (8.5%) 39 (8.5%)
123 (80.9%) 20 (13.2%) 9 (5.9%)
14595 (7.8%) 140662 (75.2%) 31705 (17.0%)
14541 (7.8%) 140215 (75.2%) 31597 (17.0%)
45 (9.8%) 335 (73.3%) 77 (16.8%)
9 (5.9%) 112 (73.7%) 31 (20.4%)
0.006
0.35
0.14
No Yes Preoperative obstructive sleep apnea No Yes Number of hypertensive medications 0 1 2 3+ Number of hypertensive medications 0 1+ Preoperative history of COPD No Yes Preoperative oxygen dependent No Yes Patient's ambulation limited most or all the time preoperative No Yes Preoperative functional health status Independent Partially Dependent Totally Dependent Pre-Op IVC filter timing IVC filter placed in anticipation of the metabolic or bariatric procedure IVC filter was pre-existing
144655 (77.4%) 42307 (22.6%)
144203 (77.4%) 42150 (22.6%)
336 (73.5%) 121 (26.5%)
116 (76.3%) 36 (23.7%)
118964 (63.6%) 67998 (36.4%)
118616 (63.7%) 67737 (36.3%)
289 (63.2%) 168 (36.8%)
59 (38.8%) 93 (61.2%)
99670 (53.3%) 39785 (21.3%) 29667 (15.9%) 17840 (9.5%)
99367 (53.3%) 39653 (21.3%) 29556 (15.9%) 17777 (9.5%)
233 (51.0%) 99 (21.7%) 80 (17.5%) 45 (9.8%)
70 (46.1%) 33 (21.7%) 31 (20.4%) 18 (11.8%)
Reference 1.23 (1, 1.52)
0.049
Reference 1.02 (0.84, 1.23)
0.86
Reference 1.06 (0.84, 1.35) 1.15 (0.9, 1.49) 1.08 (0.78, 1.48)
0.60 0.27 0.64
Reference 1.1 (0.91, 1.32)
0.32
Reference 1.28 (0.66, 2.48)
0.46
Reference 4 (2.26, 7.07)
<0.001
Reference 2.27 (1.34, 3.86)
0.002
Reference 3.28 (1.63, 6.58) 2.55 (1.14, 5.68)
0.001 0.023
<0.001
0.46
0.12 99670 (53.3%) 87292 (46.7%)
99367 (53.3%) 86986 (46.7%)
233 (51.0%) 224 (49.0%)
70 (46.1%) 82 (53.9%) 0.007
184070 (98.5%) 2892 (1.5%)
183477 (98.5%) 2876 (1.5%)
448 (98.0%) 9 (2.0%)
145 (95.4%) 7 (4.6%)
185706 (99.3%) 1256 (0.7%)
185113 (99.3%) 1240 (0.7%)
445 (97.4%) 12 (2.6%)
148 (97.4%) 4 (2.6%)
<0.001
0.001 184392 (98.6%) 2570 (1.4%)
183802 (98.6%) 2551 (1.4%)
443 (96.9%) 14 (3.1%)
147 (96.7%) 5 (3.3%)
184961 (98.9%) 1018 (0.5%) 983 (0.5%)
184366 (98.9%) 1010 (0.5%) 977 (0.5%)
443 (96.9%) 8 (1.8%) 6 (1.3%)
152 (100.0%) 0 (0.0%) 0 (0.0%)
<0.001
0.26 482 (0.3%)
479 (0.3%)
3 (0.7%)
0 (0.0%)
Reference
430 (0.2%)
427 (0.2%)
2 (0.4%)
1 (0.7%)
0.75 (0.13, 4.46)
0.75
Unknown History of MI No Yes Previous PCI/PTCA No Yes Intra-op or Post-op Myocardial Infarction No Yes Previous obesity surgery/foregut surgery No Yes Pre-Op venous stasis No Yes Current smoker within 1 year No Yes History of PE No Yes ASA Class 1-No Disturb 2-Mild Disturb 3-Severe Disturb 4-Life Threat Unknown
186050 (99.5%)
185447 (99.5%)
452 (98.9%)
151 (99.3%)
0.39 (0.13, 1.21)
0.104
Reference 1.45 (0.72, 2.91)
0.30
Reference 1.83 (1.1, 3.06)
0.021
Reference 10.35 (8.58, 12.48)
<0.001
2.25 (1.17, 4.35)
0.016
Reference 2.25 (1.17, 4.35)
0.016
Reference 1.85 (0.99, 3.46)
0.054
0.41 184685 (98.8%) 2277 (1.2%)
184087 (98.8%) 2266 (1.2%)
449 (98.2%) 8 (1.8%)
149 (98.0%) 3 (2.0%) 0.063
183562 (98.2%) 3400 (1.8%)
182971 (98.2%) 3382 (1.8%)
442 (96.7%) 15 (3.3%)
149 (98.0%) 3 (2.0%) 0.92
186910 (100.0%) 52 (<1%)
186301 (100.0%)
457 (100.0%)
152 (100.0%)
52 (<1%)
0 (0.0%)
0 (0.0%) <0.001
162339 (86.8%) 24623 (13.2%)
162056 (87.0%) 24297 (13.0%)
178 (38.9%) 279 (61.1%)
105 (69.1%) 47 (30.9%) 0.044
185310 (99.1%) 1652 (0.9%)
184711 (99.1%) 1642 (0.9%)
448 (98.0%) 9 (2.0%)
151 (99.3%) 1 (0.7%)
171783 (91.9%) 15179 (8.1%)
171231 (91.9%) 15122 (8.1%)
421 (92.1%) 36 (7.9%)
131 (86.2%) 21 (13.8%)
184726 (98.8%) 2236 (1.2%)
184130 (98.8%) 2223 (1.2%)
447 (97.8%) 10 (2.2%)
149 (98.0%) 3 (2.0%)
648 (0.3%) 42746 (22.9%) 136810 (73.2%) 5880 (3.1%) 878 (0.5%)
648 (0.3%) 42625 (22.9%) 136351 (73.2%) 5851 (3.1%) 878 (0.5%)
0 (0.0%) 90 (19.7%) 341 (74.6%) 26 (5.7%) 0 (0.0%)
0 (0.0%) 31 (20.4%) 118 (77.6%) 3 (2.0%) 0 (0.0%)
0.036
0.10
0.021
Pre-Op renal insufficiency No Yes Anticoagulation initiated of presumed/confirmed vein thrombosis/PE No Yes Pre-Op therapeutic anticoagulation No Yes Pre-Op vein thrombosis requiring therapy No Yes Pre-Op GERD requiring medication No Yes Previous cardiac surgery No Yes Pre-Op hypertensive requiring medication No Yes Previous obesity surgery/foregut surgery No Yes Pre-Op IVC Filter No Yes
0.028 186087 (99.5%) 875 (0.5%)
185485 (99.5%) 868 (0.5%)
451 (98.7%) 6 (1.3%)
151 (99.3%) 1 (0.7%)
Reference 2.83 (1.27, 6.32)
0.011
Reference 5.33 (2.76, 10.26)
<0.001
Reference 2.07 (1.39, 3.07)
<0.001
Reference 2.66 (1.68, 4.2)
<0.001
Reference 1.31 (1.08, 1.58)
0.006
Reference 2.22 (1.19, 4.15)
0.012
Reference 1.09 (0.91, 1.31)
0.34
Reference 10.35 (8.58, 12.48)
<0.001
Reference 2.22 (0.92, 5.35)
0.075
<0.001
186258 (99.6%) 704 (0.4%)
185660 (99.6%) 693 (0.4%)
448 (98.0%) 9 (2.0%)
150 (98.7%) 2 (1.3%)
181654 (97.2%) 5308 (2.8%)
181081 (97.2%) 5272 (2.8%)
431 (94.3%) 26 (5.7%)
142 (93.4%) 10 (6.6%)
<0.001
<0.001 183956 (98.4%) 3006 (1.6%)
183374 (98.4%) 2979 (1.6%)
438 (95.8%) 19 (4.2%)
144 (94.7%) 8 (5.3%)
127851 (68.4%) 59111 (31.6%)
127473 (68.4%) 58880 (31.6%)
285 (62.4%) 172 (37.6%)
93 (61.2%) 59 (38.8%)
0.003
0.034 185098 (99.0%) 1864 (1.0%)
184500 (99.0%) 1853 (1.0%)
447 (97.8%) 10 (2.2%)
151 (99.3%) 1 (0.7%) 0.13
99450 (53.2%) 87512 (46.8%)
99147 (53.2%) 87206 (46.8%)
233 (51.0%) 224 (49.0%)
70 (46.1%) 82 (53.9%) <0.001
162339 (86.8%) 24623 (13.2%)
162056 (87.0%) 24297 (13.0%)
178 (38.9%) 279 (61.1%)
105 (69.1%) 47 (30.9%) 0.18
186035 (99.5%) 927 (0.5%)
185432 (99.5%) 921 (0.5%)
452 (98.9%) 5 (1.1%)
151 (99.3%) 1 (0.7%)
Operative information procedure Bypass Others Sleeve Year of 0peration 2017 converted No conversion To open To other procedures
<0.001 44438 (23.8%) 20199 (10.8%) 122325 (65.4%)
44282 (23.8%) 19857 (10.7%) 122214 (65.6%)
85 (18.6%) 306 (67.0%) 66 (14.4%)
71 (46.7%) 36 (23.7%) 45 (29.6%)
186962 (100.0%)
186353 (100.0%)
457 (100.0%)
152 (100.0%)
Reference 7.92 (6.23, 10.07) 0.28 (0.2, 0.39)
186353 (99.7%) 457 (0.2%) 152 (0.1%)
*Association between no conversion (reference) vs converted to open; PR - prevalence ratio; SD – standard deviation; CI - confidence interval; BMI – body mass index; COPD – chronic obstructive pulmonary disease; IVC – inferior vena cava; MI – myocardial infarction; PCI/PTCA – percutaneous coronary intervention/percutaneous transcutaneous coronary angiography; ASA - American Society of Anesthesiologists; PE – pulmonary embolus; GERD – gastroesophageal reflux disease.
<0.001 <0.001
Table 2: Summary descriptive of postoperative complications Converted? Factor N Operation Length (minutes), median (IQR) Days to discharge, median (IQR) Death during operation No Yes Unplanned admission to ICU within 30 days No Yes Postoperative deep incisional surgical site infection (SSI) No Yes Deep incisional SSI present at time of surgery (PATOS) No Yes Intraoperative or postoperative myocardial infarction (MI) No Yes Postoperative organ space SSI No Yes Organ space SSI PATOS No Yes
Cohort 186962
No 186353
To Open 457
p-value
74.0 (52.0, 108.0) 1.0 (1.0, 2.0)
74.0 (51.0, 108.0) 1.0 (1.0, 2.0)
172.0 (120.0, 241.0) 4.0 (3.0, 7.0)
<0.001 <0.001 <0.001
186801 (99.9%) 161 (0.1%)
186200 (99.9%) 153 (0.1%)
450 (98.5%) 7 (1.5%)
PR (95% CI)*
p-value
2.21 (2.1, 2.3) 3.92 (3.5, 4.4)
<0.001 <0.001
18.15 (8.7, 37.7)
<0.001
15.3 (11.3, 20.7)
<0.001
37.93 (23.2, 62.0)
<0.001
117.82 (51.2, 271.1)
<0.001
22.34 (15.5, 32.2)
<0.001
48.72 (26.2, 90.6)
<0.001
<0.001 185634 (99.3%) 1328 (0.7%)
185074 (99.3%) 1279 (0.7%)
412 (90.2%) 45 (9.8%) <0.001
186794 (99.9%) 168 (0.1%)
186201 (99.9%) 152 (0.1%)
442 (96.7%) 15 (3.3%) <0.001
186948 (100.0%) 14 (<1%)
186343 (100.0%) 10 (<1%)
453 (99.1%) 4 (0.9%) 0.72
186910 (100.0%) 52 (<1%)
186301 (100.0%) 52 (<1%)
457 (100.0%) 0 (0.0%) <0.001
186396 (99.7%) 566 (0.3%)
185817 (99.7%) 536 (0.3%)
428 (93.7%) 29 (6.3%) <0.001
186885 (100.0%) 77 (<1%)
186285 (100.0%) 68 (<1%)
448 (98.0%) 9 (2.0%)
Number of postoperative pneumonia occurrences
<0.001 0 1
Pneumonia PATOS No Yes Progressive renal insufficiency No Yes Pulmonary embolism No Yes Postoperative sepsis No Yes Sepsis PATOS No Yes Number of postoperative septic shock occurrences
185957 (99.8%) 396 (0.2%)
445 (97.4%) 12 (2.6%)
12.32 (7.0, 21.7)
<0.001
20.87 (9.5, 45.8)
<0.001
10.12 (4.2, 24.2)
<0.001
28.38 (17.8, 45.3)
<0.001
51.54 (20.5, 129.5)
<0.001
28.6 (15.6, 52.4)
<0.001
184.9 (109.4, 312.5)
<0.001
14.47 (10.1, 20.7)
<0.001
0.85 186948 (100.0%) 14 (<1%)
186339 (100.0%) 14 (<1%)
457 (100.0%) 0 (0.0%) <0.001
186843 (99.9%) 119 (0.1%)
186240 (99.9%) 113 (0.1%)
451 (98.7%) 6 (1.3%) <0.001
186758 (99.9%) 204 (0.1%)
186154 (99.9%) 199 (0.1%)
452 (98.9%) 5 (1.1%) <0.001
186707 (99.9%) 255 (0.1%)
186116 (99.9%) 237 (0.1%)
440 (96.3%) 17 (3.7%) <0.001
186930 (100.0%) 32 (<1%)
186325 (100.0%) 28 (<1%)
453 (99.1%) 4 (0.9%) <0.001
0 1 Septic shock PATOS No Yes Postoperative superficial incisional SSI No Yes Superficial incisional SSI PATOS
186554 (99.8%) 408 (0.2%)
186815 (99.9%) 147 (0.1%)
186217 (99.9%) 136 (0.1%)
447 (97.8%) 10 (2.2%)
186944 (100.0%) 18 (<1%)
186343 (100.0%) 10 (<1%)
449 (98.2%) 8 (1.8%)
<0.001
<0.001 186026 (99.5%) 936 (0.5%)
185449 (99.5%) 904 (0.5%)
426 (93.2%) 31 (6.8%) <0.001
No Yes Transfusion intraoperative/postoperative (72 hours of surgery start time) No Yes Number of units transfused (1-200), median (IQR) Bleeding units 1 2 3 Unplanned intubation No Yes Postoperative urinary tract infection (UTI) No Yes UTI PATOS No Yes Postoperative vein thrombosis requiring therapy No Yes Wound disruption No Yes Unplanned admission to ICU within 30 days
186941 (100.0%) 21 (<1%)
186336 (100.0%) 17 (<1%)
453 (99.1%) 4 (0.9%)
78.54 (32.4, 190.6)
<0.001
16.21 (11.9, 22.0)
<0.001
0.76 (0.4, 1.6) 1.09 (0.5, 2.4)
0.48 0.828
18.23 (9.9, 33.7)
<0.001
4.2 (2.0, 8.9)
<0.001
21.65 (7.2, 65.4)
<0.001
3.85 (1.2, 11.9)
0.019
20.19 (9.2, 44.3)
<0.001
<0.001 185740 (99.3%) 1222 (0.7%) 2.0 (2.0, 3.0)
185177 (99.4%) 1176 (0.6%) 2.0 (2.0, 3.0)
413 (90.4%) 44 (9.6%) 2.0 (2.0, 3.0)
0.61 0.55
258 (0.1%) 606 (0.3%) 352 (0.2%) 185746 (99.3%)
246 (0.1%) 588 (0.3%) 337 (0.2%) 185182 (99.4%)
10 (2.2%) 18 (3.9%) 15 (3.3%) 414 (90.6%) <0.001
186733 (99.9%) 229 (0.1%)
186134 (99.9%) 219 (0.1%)
447 (97.8%) 10 (2.2%) <0.001
186271 (99.6%) 691 (0.4%)
185670 (99.6%) 683 (0.4%)
450 (98.5%) 7 (1.5%) <0.001
186905 (100.0%) 57 (<1%)
186299 (100.0%) 54 (<1%)
454 (99.3%) 3 (0.7%) 0.012
186641 (99.8%) 321 (0.2%)
186036 (99.8%) 317 (0.2%)
454 (99.3%) 3 (0.7%)
186839 (99.9%) 123 (0.1%)
186236 (99.9%) 117 (0.1%)
451 (98.7%) 6 (1.3%)
<0.001
<0.001
No Yes Acute renal failure (ARF) No Yes Intraoperative or postoperative cardiac arrest requiring CPR No Yes Morbidity No Yes Readmission within 30 days of operation No Yes Reoperation within 30 days of operation No Yes Revision within 30 days of operation No Yes Intervention within 30 days of operation No Yes
185634 (99.3%) 1328 (0.7%)
185074 (99.3%) 1279 (0.7%)
412 (90.2%) 45 (9.8%)
15.3 (11.3, 20.7)
<0.001
6.84 (1.7, 27.1)
0.006
26.15 (11.1, 61.4)
<0.001
17.14 (14.1, 20.8)
<0.001
5.74 (4.5, 7.3)
<0.001
12.23 (9.5, 15.8)
<0.001
7.97 (6.6, 9.6)
<0.001
6.94 (5.0, 9.7)
<0.001
0.002 186842 (99.9%) 120 (0.1%)
186235 (99.9%) 118 (0.1%)
455 (99.6%) 2 (0.4%) <0.001
186883 (100.0%) 79 (<1%)
186279 (100.0%) 74 (<1%)
452 (98.9%) 5 (1.1%) <0.001
181723 (97.2%) 5239 (2.8%)
181275 (97.3%) 5078 (2.7%)
306 (67.0%) 151 (33.0%) <0.001
179993 (96.3%) 6969 (3.7%)
179479 (96.3%) 6874 (3.7%)
374 (81.8%) 83 (18.2%) <0.001
184411 (98.6%) 2551 (1.4%)
183876 (98.7%) 2477 (1.3%)
391 (85.6%) 66 (14.4%) <0.001
179993 (96.3%) 6969 (3.7%)
179479 (96.3%) 6874 (3.7%)
374 (81.8%) 83 (18.2%) <0.001
184619 (98.7%) 2343 (1.3%)
184049 (98.8%) 2304 (1.2%)
420 (91.9%) 37 (8.1%)
*Association between no conversion (reference) vs converted to open; PR - prevalence ratio; CI – confidence interval; IQR – interquartile range; intensive care unit – ICU; CPR – cardiopulmonary resuscitation.
Table 3: Adjusted Associations
Operation Length; RC (95% CI)+ Days to discharge from operation; RC (95% CI)++ Death* Morbidity** Re – operation*** Re – intervention**** Re – admission*****
OR 94.92 4.81 7.52 11.54 6.97 4.28 4.01
95% CI P value 89.39 100.44 <0.001 4.65 4.96 <0.001 2.84 9.00 5.02 2.84 2.97
19.91 14.80 9.69 6.44 5.41
<0.001 <0.001 <0.001 <0.001 <0.001
OR: odds ratio; CI: confidence interval; modelled for converted to open vs. no conversion (reference); RC- regression coefficient. +Adjusted for : Age, BMI (body mass index), Albumin, HCT (hematocrit), Race, hyperlipidemia, oxygen dependency, mobility device, history of DVT (deep venous thrombosis), functional health status, GERD (gastroesophageal reflux disease), previous surgery, venous status, smoker, IVC (inferior vena cava) filter, ASACLASS (American Society of Anesthesiologist Classification), renal insufficiency, anticoagulation, therapeutic anticoagulation; ++Adjusted for: Age, BMI, albumin, HCT, Race, hyperlipidemia, oxygen dependency, mobility device, functional health status, history of DVT, PTC (percutaneous transluminal coronary angiography), previous surgery, IVC filter, GERD, ASACLASS, PCARD (previous cardiac surgery), renal insufficiency, Anticoagulation, therapeutic anticoagulation; *Adjusted for: Age, BMI, history of DVT, HCT, Race, ASACLASS, oxygen dependency, anticoagulation, PTC, Previous surgery, therapeutic anticoagulation; **Adjusted for: Age, BMI, Albumin, HCT, ASACLASS, Race, History of DVT, hyperlipidemia, oxygen dependency, mobility device, GERD, renal insufficiency, PTC, previous surgery, venous status, anticoagulation, therapeutic anticoagulation; ***Adjusted for: Age, BMI, Albumin, Anticoagulation, Race, GERD, smoker, oxygen dependency, ASACLASS, functional health status, History DVT, previous surgery, therapeutic anticoagulation; ****Adjusted for: Age, anticoagulation, Albumin, HCT, therapeutic, Race, IVC filter, PCARD, mobility device, GERD, functional health status, ASACLASS, previous surgery; *****Adjusted for: ASACLASS, GERD, Albumin, HCT, therapeutic anticoagulation, Race, hyperlipidemia, oxygen dependency, mobility, functional health status, renal insufficiency, PCARD, previous surgery, anticoagulation, smoker, history of DVT.
Table 4: Adjusted analysis on propensity matched cohort OR
95% CI
P value
<0.001 98.41 86.06 110.76 Operation Length; RC (95% CI) Days to discharge from operation; RC (95% 3.80 5.66 <0.001 4.73 CI) 1.88 1.67 2.11 <0.001 Death 4.63 3.08 6.96 <0.001 Morbidity 6.42 2.92 14.11 <0.001 Re – operation 3.75 1.65 8.53 0.002 Re – intervention 2.65 1.72 4.1 <0.001 Re – admission OR: odds ratio; CI: confidence interval; modelled for converted to open vs. no conversion (reference); RC- regression coefficient. Adjusted for: Diabetes, myocardial infarction, and American Society of Anesthesiologist Classification.
Highlights: This paper uses data from the MBSAQIP database to evaluate the outcomes of patients undergoing metabolic and bariatric surgery that were converted from a minimally invasive technique to open surgery. They have higher rates of morbidity and mortality.
S1550-7289(20)30046-0
DOI:
https://doi.org/10.1016/j.soard.2020.01.026
Reference:
SOARD 4044
To appear in:
Surgery for Obesity and Related Diseases
Received Date: 30 September 2019 Revised Date:
26 November 2019
Accepted Date: 25 January 2020
Please cite this article as: Clapp B, Liggett E, Phan C, Dodoo C, Lee I, Cutshall M, Tyroch A, Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database., Surgery for Obesity and Related Diseases (2020), doi: https://doi.org/10.1016/j.soard.2020.01.026. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.
Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database.
Benjamin Clapp MD, Evan Liggett MD, Cong Phan, Christopher Dodoo MS, Isaac Lee MD, Michael Cutshall MD, Alan Tyroch MD.
All authors are affiliated with Texas Tech Health Sciences Center Paul Foster School of Medicine
There are no funding sources for this work.
Short title: Conversions MBSAQIP
Conversions to open surgery greatly increase complications: an analysis of the MBSAQIP database.
Benjamin Clapp MD, Evan Liggett MD, Cong Phan, Christopher Dodoo MS, Isaac Lee MD, Michael Cutshall MD, Alan Tyroch MD.
Background: The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database tracks patients, techniques and outcomes for 30 days. The overwhelming majority of cases reported are performed using a laparoscopic technique. Bariatric surgeons rarely have to convert from laparoscopy to open surgery. Objectives: We examined the MBSAQIP to determine the characteristics of patients who underwent conversion and evaluated their short-term outcomes. Settings: University program in the United States and nationwide clinical database. Methods: The MBSAQIP Public Use File for 2017 was examined for primary bariatric operations. We identified patients who underwent a sleeve gastrectomy (SG) or gastric bypass (LRYGB) using a minimally invasive technique. We identified patients who underwent conversion to another operative technique or were converted to open surgery and analyzed preoperative characteristics and postoperative complication rates. Relative risks (RR) were calculated for complications. P was significant at < 0.05. Results: There were 186,962 patients in the entire cohort. 609 patients underwent conversion from the original surgical approach to either open surgery (n=457) or to another technique (n=152). Patients with preoperative oxygen dependency, poor functional status, previous foregut/obesity surgery, preoperative renal insufficiency and anticoagulation were more likely to
undergo conversion. Patients who underwent conversion to the open approach had longer operative times (191 vs 86.6 minutes [P<0.00]) and longer time to discharge (6.2 vs 1.6 days [P<0.001]). The RR of death was 18.2 (95%CI 8.7-37.6, P<0.001) for procedures converted to open. The RR of sepsis was 10.1 (95%CI 4.2-24.2, P<0.001) and the RR for all complications was increased throughout for patients undergoing conversion. Conclusions: Patients in the MBSAQIP database that undergo conversion to the open surgical approach are at a greatly increased risk for death and complications.
Key words: conversion to open surgery, conversions, MBSAQIP, bariatric surgery
Introduction In the last few decades, laparoscopy has largely influenced surgical practice and became the standard of care for general surgery abdominal operations and bariatric procedures. Overall, complication rates associated with laparoscopic surgery remains low [1]. Laparoscopic metabolic and bariatric surgery (MBS) has become the normal technique in the United States. The laparoscopic approach is the most common technique employed, but conversion to open laparotomy is still sometimes necessary. It is rare today to perform open MBS, even for revisions. In fact, when compared to other disciplines in general surgery, MBS has the lowest conversion rate [2]. It is now expected that bariatric surgery will take place laparoscopically, with either a traditional laparoscopic technique or a robotic assisted laparoscopic technique. However, surgeons still recognize the need to fall back on open surgery occasionally. This is usually not seen as a failure but instead an exercise in good judgment. Reasons for converting to open range from such factors as bleeding, lack of abdominal wall compliance, or failure to progress. Conversions can be classified into two separate categories: reactive conversion and preemptive conversion. Reactive conversion occurs as a result of an intraoperative complication, whereas preemptive conversion is one that is undertaken to avoid one [3]. When the surgeon determines it is dangerous, futile or foolish to continue using a laparoscopic technique, a change to another approach makes sense. The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database collects 30-day outcomes on patients, including preoperative patient characteristics, operative details and postoperative outcomes. We proposed examining the Participant Use Data File (PUF) to determine the characteristics of the patients who underwent a conversion from laparoscopy to open. We also examined robotic to laparoscopic or open cases as
well as hand assisted. Our outcomes of interest were patient characteristics, operative details and postoperative outcomes of patients that underwent conversion.
Methods The MBSAQIP PUF for 2017 was used to analyze data for primary bariatric operations and revisions. The MBSAQIP PUF is a bariatric surgery–specific clinical data set, which contains approximately 200 variables including preoperative patient characteristics, procedure details, as well as details on complications, reoperations, readmissions, or interventions within 30 days. The MBSAQIP-PUF does not identify hospitals or individual healthcare providers. Data are collected prospectively and entered into the database by trained abstractors at each site. Data are based on standardized definitions for preoperative, intraoperative, and postoperative variables specific to bariatric surgery. Extensive efforts are made to ensure quality and reliability of data across sites by regular auditing and training of data abstractors. We identified patients who underwent a sleeve gastrectomy or gastric bypass using a minimally invasive technique. We then identified patients who underwent conversion to another operative technique or were converted to open surgery and examined preoperative characteristics and postoperative complication rates. Relative risks (RR) were calculated for complications. P was significant at < 0.05. To reflect a typical patient population, inclusion was restricted to patients with a body mass index (BMI) of 35 to 70 kg/m2. We used the fields SURGICAL APPROACH, APPROACH_CONVERTED, and CONVERISON. APPROACH_CONVERTED has a yes/no answer, the other two have the following options: single Incision robotic-assisted, conventional laparoscopic (thoracoscopic), laparoscopic assisted (thoracoscopic assisted) and hand-assisted.
Exclusion criteria included patients who underwent hiatal hernia repair, emergency procedures, or unrelated concurrent procedures, such as hysterectomy. We also excluded patients who were >80 years old, those requiring dialysis preoperatively, and American Society of Anesthesiology (ASA) Class 5 (moribund). Additionally, 30-day readmission data were extracted from the separate readmission file by matching the unique case identification numbers for each patient included in the study. Two primary composite outcomes of interest included patient and operative characteristics of those that required conversion to open and outcomes. All-cause morbidity was comprised of 30-day mortality, unplanned admission to intensive care unit, readmissions, reoperation, reintervention, surgical site infection (SSI - composite of superficial and deep SSI), organ/space SSI, wound disruption, deep vein thrombosis (vein thrombosis requiring therapy), pulmonary embolism, postoperative pneumonia, ventilator use for>48 hours, intraoperative or postoperative myocardial infarction, intraoperative or postoperative cardiac arrest requiring cardiopulmonary resuscitation, stroke or cerebrovascular event, coma lasting>24 hours, unplanned intubation, acute renal failure, progressive renal insufficiency, postoperative urinary tract infection, intraoperative or postoperative transfusion performed within 72 hours of surgery, peripheral nerve injury, postoperative sepsis, and postoperative septic shock. Secondary outcomes of interest included operative time, length of hospital stay, 30-day rates of readmission, reoperation and reintervention. This study was exempt from institutional review board approval, as data were publicly available in a de-identified manner. The hospitals participating in the MBSAQIP are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.
Statistical analysis Quantitative variables were summarized using mean and standard deviations (SD). Categorical variables were summarized using frequencies and proportions. To access the baseline differences in patient characteristics, operation characteristics and preoperative comorbidities, the student's t-test and chi-squared test were used. Unadjusted and adjusted factors affecting postoperative complications were assessed using generalized linear models with a link log and family Poisson, and logistic regression models. These measures were reported as prevalence ratio (PR) and odds ratio (OR), together with their 95% confidence interval (CI). P values of less than 5 % were considered statistically significant. We generated propensity scores for conversion [to open] or no conversions using a logistic regression model adjusted for known baseline characteristics, operation information and preoperative comorbidities. A backward -stepwise selection with an entry level of 0.05 was used to obtain the significant variables. A propensity score between 0 – 1 was then generated for each patient using the significant variables. Based on the obtained propensity scores, two evenly matched groups were generated based on conversion status using a matching algorithm with the common caliper set at 0.005. This resulted in 652 (326 in each group). The matched cohort was further assessed for balance by assessing differences across all the potential confounders (refer to supplementary tables 1 and 2). Further risk adjustment checks were done using multivariate analysis with adjustments done for covariates that remained unbalanced between the 2 matched groups. All analyses were carried out using STATA v.15.
Results
There were 186,962 patients in the entire cohort for 2017. Only 609 patients underwent conversion from the original surgical technique to either open surgery (n=457) or to another technique (n=152). This gives a conversion rate of 0.3% from laparoscopic to open surgery. The highest rate of conversion by case was the LRYGB at 0.2%. SG were converted at a rate of 0.05%. There were 112 (0.06%) cases of laparoscopic converted to “other” and for robot conversions to “other” there were 40 cases (0.28%). For conversion to open, there were 435 (0.25%) of laparoscopic to open and 22 (0.15%) for robotic to open. But in the propensity matched analysis there was no difference between laparoscopic vs robotic (50.2% vs 45.7%, P = 0.6). Table 1 summarizes the baseline characteristics of the total study population and the conversion to open group. Patients converted to open surgery had higher rates of oxygen dependency, poor functional status, previous foregut/obesity surgery, preoperative renal insufficiency and were chronically anticoagulated. Patients undergoing conversion to open had longer operative times (87 vs 191 minutes, P < 0.001), longer time to discharge (1.6 vs 6.2 days, P < 0.001). When the one approach was converted to other than open (i.e. robot to laparoscopic), the operative time increased to 160 minutes and length of stay was extended to 2.4 days. Table 2 summarizes postoperative complications. There were 161 deaths in the total cohort for a rate of 0.09%, but the mortality rate of patients converted to open was much higher at 1.53% (P < 0.001). There were statistically significant differences across the board in complications in patients that were converted to open, but clinically significant complications were admission to ICU, SSI, and transfusion. There were also higher rates of readmission, reintervention and revision within 30 days. Table 3 demonstrates the adjusted associations for postoperative morbidity and mortality. The OR of death was 7.52 (95%CI 2.84-19.9, P < 0.001). The OR for overall morbidity was
11.5 (95%CI 9.0-14.8, P < 0.001). The risks of readmission, reintervention and reoperation were increased by at least four-fold. After propensity matched scoring, the result trends remain the same, but with smaller effect sizes (Table 4).
Discussion This is the largest study to date examining conversion from the laparoscopic to the open technique in bariatric surgery. The most significant finding of our paper is the lack of conversions. US and Canadian surgeons have been able to drop the conversion rate of very complex laparoscopic procedures to a rate of 0.2%. This is an astoundingly low rate that has improved from previous years. Our main results show that when propensity matched analysis is performed, converted patients have longer operative times, longer length of stay and higher rates of death and morbidity. The MBSAQIP database does not have the granularity to determine if procedures were aborted or switched intraoperatively to another procedure, i.e. SG to LRYGB. We may be missing these cases as a “conversion” as this situation has no method of recording in the PUF. Nguyen et al used the University Health System Consortium database to examine postoperative complications and in a sample of almost 54,000 patients undergoing bariatric surgery from 2008-2012 and found a conversion rate of 0.89% [2]. When this data was broken down by the type of bariatric surgery, the rate for conversion was greatest for LRYGB (2.5%), followed by laparoscopic SG (0.11%) and laparoscopic adjustable gastric banding (0.07%). The current reported rates for the 2017 MBSAQIP data show an improvement over these already low numbers. A recent study using the MBSAQIP data comparing robotic to laparoscopic surgery showed higher conversion rates in the robotic group with rates either for SG (0.53% vs. 0.12%; P <0.001) and for RYGB (0.57% vs. 0.26%; P =0.01). This was data from 2015-2016 [4]. The
LRGYB remains the most commonly converted operation. Conversion rates are so low that a paper was published in Obesity Surgery in 2016 reviewing the technique of open gastric bypass [5]. Other interesting findings were the preoperative characteristics of patients undergoing conversion to open surgery. We found patients converted to open surgery had higher rates of oxygen dependency, poor functional status, previous foregut/obesity surgery, preoperative renal insufficiency and were chronically anticoagulated. This likely indicates that sicker patients and patients with previous foregut/obesity surgery are more difficult technically. The reported rates of intraoperative conversion from laparoscopic to open surgery vary greatly depending on the type of procedure performed. Conversion rates have been reported as 2.6%-10% in cholecystectomy; 29.8% in diverticulitis surgery; 21% in IBD [3] and 4.2% in gastric bypass [6]. The most common reasons for conversion are severe adhesions caused by tissue inflammation [7], inability to correctly identify anatomy [8], and BMI (and waist circumference) [9]. Conversions can be classified according to perceived cause. Yang et al. described limitations of the disease process (adhesions, phlegmon etc.), technical problems (unclear anatomy), and intraoperative complications (bleeding, bowel injury, ureteral damage and splenic injury) [3]. Lengyel et al. used the NSQIP database to look at reasons for conversion in cholecystectomy. They had a 5.8% conversion to open rate, and the majority of those seemed to be converted early, perhaps from immediate assessment by the surgeon of perceived difficulty [10]. For the treatment of acute cholecystitis, lower surgeon volume was also a predictor of the need for open conversion and prolonged length of hospital stay [11]. The MBSAQIP can elucidate patient characteristics but does not have the granularity to describe reasons for conversion to the open technique. Our paper shows an extremely low rate of conversion to open,
but we cannot make any statements as to the cause of opening. We initially thought we would at least be able to tell bleeding complications as a reason, but there was a non-significant difference between the groups. We examined some operative characteristics such as blood loss but this is listed as “transfusion intra-op/post-op (72 hours of surgery start time).” This does not tell us if the blood loss was the cause of the conversion vs a consequence of conversion. We also can draw some conclusions about adhesions as patients with previous foregut/obesity surgery had higher risks of conversion. This conceivably could be related to adhesions from previous operations. This is a lack of granularity of the MBSAQIP data that all researchers using the PUF struggle with. Although there is no way to tease out the reasons for conversion, when they occurred, they greatly increased the risks of death and complications. Surgeons may consider this when making an intraoperative decision to perform and elective conversion, but they still need to be ready to convert in emergencies situations such as uncontrolled bleeding. The most common complications in the aforementioned studies were prolonged ileus, pneumonia and SSI. In a previous study, the patients in the conversion group were also more likely to experience a longer time to regular diet (5-6 vs 4.4 days), longer hospital stay (7.1-8.1 vs 5.3 days), longer time to flatus (4.76-5.4 vs 3.2 days), and a higher postoperative complication rate (27% to 50% vs 11.7%) [3]. This is similar to our results with the greatly increased RR of sepsis, infectious complications and death.
Strengths and limitations Administrative databases are inherently subject to reporting bias if there are errors in the diagnosis or procedure codes that are used. However, for the MBSAQIP database, extensive
efforts are made to ensure quality and reliability of data across sites by regular auditing and training of data abstractors. Being able to pool this highly reliable data means we can feel confident that our results truly reflect the state of surgery at those centers that report the data. That being said, we are missing data from surgeries performed at non-accredited centers. Data reported in the MBSAQIP may be significantly different from the non-accredited centers and therefore not generalizable. Additionally, the PUF is also de-identified for HIPAA purposes, making it impossible to determine the impact of surgeon experience on conversion rates. More experienced laparoscopic surgeons may have much different rates of conversion and postoperative complications than less-experienced surgeons, but there is simply not a way for us to tease that out as the de-identification prevents such granularity. Another limitation is that this is a retrospective study and it is subject to the disadvantages of such studies, including the inability to determine causation, only association.
Conclusions Patients undergoing MBS today are at an extremely low risk of conversion from laparoscopy to an open technique. Patients in the MBSAQIP database that did undergo conversion to the open surgical technique are at a greatly increased risk for death and complications.
Conflict of interest statement: none of the authors have a conflict of interest.
Table 1. Summary descriptive of baseline characteristics in entire cohort and by conversions. Table 2. Summary descriptive of postoperative complications. Table 3. Unadjusted associations for morbidity and mortality. Table 4. Adjusted analysis on propensity matched cohort
References
1. Perugini RA, Callery MP. Complications of laparoscopic surgery. In: Holzheimer RG, Mannick JA, editors. Surgical Treatment: Evidence-Based and Problem-Oriented. Munich: Zuckschwerdt; 2001. 2. Nguyen NT, Nguyen B, Shih A, Smith B, Hohmann S. Use of laparoscopy in general surgical operations at academic centers. Surg Obes Relat Dis. 2013;9(1):15-20. doi: 10.1016/j.soard.2012.07.002. Epub 2012 Jul 16. 3. Yang C, Wexner SD, Safar B, et al. Conversion in laparoscopic surgery: does intraoperative complication influence outcome? Surg Endosc. 2009;23(11):2454-2458. doi:10.1007/s00464009-0414-6. 4. Sebastian R, Howell MH, Chang KH, Adrales G, Magnuson T, Schweitzer M, Nguyen H. Robot-assisted versus laparoscopic Roux-en-Y gastric bypass and sleeve gastrectomy: a propensity score-matched comparative analysis using the 2015-2016 MBSAQIP database. Surg Endosc. 2019;33(5):1600-1612. doi: 10.1007/s00464-018-6422-7. Epub 2018 Sep 17. 5. Jones, KB. When and how to "open" in laparoscopic or robotic surgery. Obes Surg. 2016;26(4):891-5. doi: 10.1007/s11695-016-2095-2. 6. Schwartz ML, Drew RL, Chazin-Caldie M. Laparoscopic Roux-en-Y gastric bypass: preoperative determinants of prolonged operative times, conversion to open gastric bypasses, and postoperative complications. Obes Surg. 2003;13(5):734-738. doi:10.1381/096089203322509309.
7. Genc V, Sulaimanov M, Cipe G, et al. What necessitates the conversion to open cholecystectomy? A retrospective analysis of 5164 consecutive laparoscopic operations. Clinics. 2011;66(3):417-420. doi:10.1590/s1807-59322011000300009. 8. Bingener-Casey J. Reasons for conversion from laparoscopic to open cholecystectomy; a 10year review. J Gastrointest Surg. 2002;6(6):800-805. doi:10.1016/s1091-255x(02)00064-1. 9. Schwartz M, Drew R, Chazin-Caldie M. Factors determining conversion from laparoscopic to open Roux-en-Y gastric bypass. Obes Surg. 2004;14(9):1193-1197. doi:10.1381/0960892042386887. 10. Lengyel B, Azagury D, Varban O, Panizales M, Steinberg J, Brooks DC, Ashley SW, Tavakkolizadeh A. Laparoscopic cholecystectomy after a quarter century: why do we still convert? Surg Endosc. 2012;26(2):508-13. doi: 10.1007/s00464-011-1909-5. Epub 2011 Sep 23. 11. Csikesz N, Singla A, Murphy M, Tseng J, Shah S. Surgeon volume metrics in laparoscopic cholecystectomy. Dig Dis Sci. 2009;55(8):2398-2405. doi:10.1007/s10620-009-1035-6.
Table 1: Summary descriptive of baseline characteristics in entire cohort, and by conversions Converted? Factor Cohort No To Open N 186962 186353 457 DEMOGRAPHICS Age, mean (SD) BMI, mean (SD) Albumin Lab Value, mean (SD) Hematocrit Lab Value, mean (SD) Operation Length (minutes), mean (SD) Days to discharge, mean (SD) Sex Female Male Race Black Others Unknown White Hispanic Ethnicity No Unknown Yes Preoperative comorbidities Preoperative diabetes mellitus Insulin No Non-Insulin Preoperative hyperlipidemia
To Others 152
p-value
PR (95% CI)*
P-value
45.2 (12.0) 44.5 (7.3) 4.0 (0.4) 40.7 (3.9) 87.0 (52.0)
45.2 (12.0) 44.5 (7.2) 4.0 (0.4) 40.7 (3.9) 86.6 (51.6)
51.5 (10.7) 43.4 (8.8) 3.9 (0.5) 39.8 (4.9) 191.2 (96.2)
45.9 (11.2) 47.4 (8.5) 3.9 (0.4) 40.8 (4.0) 160.9 (75.2)
<0.001 <0.001 <0.001 <0.001 <0.001
1.04 (1.04, 1.05) 0.98 (0.96, 1) 0.37 (0.29, 0.46) 0.95 (0.93, 0.97) 1.01 (1.01, 1.01)
<0.001 0.013 <0.001 <0.001 <0.001
1.6 (1.5)
1.6 (1.4)
6.2 (7.5)
2.4 (3.3)
<0.001 0.22
1.11 (1.1, 1.12)
<0.001
150610 (80.6%) 36352 (19.4%)
150136 (80.6%) 36217 (19.4%)
354 (77.5%) 103 (22.5%)
120 (78.9%) 32 (21.1%)
Reference 1.21 (0.97, 1.5)
0.094
Reference 1.95 (1.01, 3.76) 0.57 (0.35, 0.92) 1.09 (0.85, 1.39)
0.046 0.022 0.51
Reference 0.91 (0.65, 1.26) 0.66 (0.48, 0.92)
0.55 0.014
Reference 0.77 (0.57, 1.05) 0.79 (0.55, 1.14)
0.104 0.20
0.018 33124 (17.7%) 2178 (1.2%) 15655 (8.4%) 136005 (72.7%)
33025 (17.7%) 2167 (1.2%) 15623 (8.4%) 135538 (72.7%)
78 (17.1%) 10 (2.2%) 21 (4.6%) 348 (76.1%)
21 (13.8%) 1 (0.7%) 11 (7.2%) 119 (78.3%)
147311 (78.8%) 16751 (9.0%) 22900 (12.2%)
146809 (78.8%) 16692 (9.0%) 22852 (12.3%)
379 (82.9%) 39 (8.5%) 39 (8.5%)
123 (80.9%) 20 (13.2%) 9 (5.9%)
14595 (7.8%) 140662 (75.2%) 31705 (17.0%)
14541 (7.8%) 140215 (75.2%) 31597 (17.0%)
45 (9.8%) 335 (73.3%) 77 (16.8%)
9 (5.9%) 112 (73.7%) 31 (20.4%)
0.006
0.35
0.14
No Yes Preoperative obstructive sleep apnea No Yes Number of hypertensive medications 0 1 2 3+ Number of hypertensive medications 0 1+ Preoperative history of COPD No Yes Preoperative oxygen dependent No Yes Patient's ambulation limited most or all the time preoperative No Yes Preoperative functional health status Independent Partially Dependent Totally Dependent Pre-Op IVC filter timing IVC filter placed in anticipation of the metabolic or bariatric procedure IVC filter was pre-existing
144655 (77.4%) 42307 (22.6%)
144203 (77.4%) 42150 (22.6%)
336 (73.5%) 121 (26.5%)
116 (76.3%) 36 (23.7%)
118964 (63.6%) 67998 (36.4%)
118616 (63.7%) 67737 (36.3%)
289 (63.2%) 168 (36.8%)
59 (38.8%) 93 (61.2%)
99670 (53.3%) 39785 (21.3%) 29667 (15.9%) 17840 (9.5%)
99367 (53.3%) 39653 (21.3%) 29556 (15.9%) 17777 (9.5%)
233 (51.0%) 99 (21.7%) 80 (17.5%) 45 (9.8%)
70 (46.1%) 33 (21.7%) 31 (20.4%) 18 (11.8%)
Reference 1.23 (1, 1.52)
0.049
Reference 1.02 (0.84, 1.23)
0.86
Reference 1.06 (0.84, 1.35) 1.15 (0.9, 1.49) 1.08 (0.78, 1.48)
0.60 0.27 0.64
Reference 1.1 (0.91, 1.32)
0.32
Reference 1.28 (0.66, 2.48)
0.46
Reference 4 (2.26, 7.07)
<0.001
Reference 2.27 (1.34, 3.86)
0.002
Reference 3.28 (1.63, 6.58) 2.55 (1.14, 5.68)
0.001 0.023
<0.001
0.46
0.12 99670 (53.3%) 87292 (46.7%)
99367 (53.3%) 86986 (46.7%)
233 (51.0%) 224 (49.0%)
70 (46.1%) 82 (53.9%) 0.007
184070 (98.5%) 2892 (1.5%)
183477 (98.5%) 2876 (1.5%)
448 (98.0%) 9 (2.0%)
145 (95.4%) 7 (4.6%)
185706 (99.3%) 1256 (0.7%)
185113 (99.3%) 1240 (0.7%)
445 (97.4%) 12 (2.6%)
148 (97.4%) 4 (2.6%)
<0.001
0.001 184392 (98.6%) 2570 (1.4%)
183802 (98.6%) 2551 (1.4%)
443 (96.9%) 14 (3.1%)
147 (96.7%) 5 (3.3%)
184961 (98.9%) 1018 (0.5%) 983 (0.5%)
184366 (98.9%) 1010 (0.5%) 977 (0.5%)
443 (96.9%) 8 (1.8%) 6 (1.3%)
152 (100.0%) 0 (0.0%) 0 (0.0%)
<0.001
0.26 482 (0.3%)
479 (0.3%)
3 (0.7%)
0 (0.0%)
Reference
430 (0.2%)
427 (0.2%)
2 (0.4%)
1 (0.7%)
0.75 (0.13, 4.46)
0.75
Unknown History of MI No Yes Previous PCI/PTCA No Yes Intra-op or Post-op Myocardial Infarction No Yes Previous obesity surgery/foregut surgery No Yes Pre-Op venous stasis No Yes Current smoker within 1 year No Yes History of PE No Yes ASA Class 1-No Disturb 2-Mild Disturb 3-Severe Disturb 4-Life Threat Unknown
186050 (99.5%)
185447 (99.5%)
452 (98.9%)
151 (99.3%)
0.39 (0.13, 1.21)
0.104
Reference 1.45 (0.72, 2.91)
0.30
Reference 1.83 (1.1, 3.06)
0.021
Reference 10.35 (8.58, 12.48)
<0.001
2.25 (1.17, 4.35)
0.016
Reference 2.25 (1.17, 4.35)
0.016
Reference 1.85 (0.99, 3.46)
0.054
0.41 184685 (98.8%) 2277 (1.2%)
184087 (98.8%) 2266 (1.2%)
449 (98.2%) 8 (1.8%)
149 (98.0%) 3 (2.0%) 0.063
183562 (98.2%) 3400 (1.8%)
182971 (98.2%) 3382 (1.8%)
442 (96.7%) 15 (3.3%)
149 (98.0%) 3 (2.0%) 0.92
186910 (100.0%) 52 (<1%)
186301 (100.0%)
457 (100.0%)
152 (100.0%)
52 (<1%)
0 (0.0%)
0 (0.0%) <0.001
162339 (86.8%) 24623 (13.2%)
162056 (87.0%) 24297 (13.0%)
178 (38.9%) 279 (61.1%)
105 (69.1%) 47 (30.9%) 0.044
185310 (99.1%) 1652 (0.9%)
184711 (99.1%) 1642 (0.9%)
448 (98.0%) 9 (2.0%)
151 (99.3%) 1 (0.7%)
171783 (91.9%) 15179 (8.1%)
171231 (91.9%) 15122 (8.1%)
421 (92.1%) 36 (7.9%)
131 (86.2%) 21 (13.8%)
184726 (98.8%) 2236 (1.2%)
184130 (98.8%) 2223 (1.2%)
447 (97.8%) 10 (2.2%)
149 (98.0%) 3 (2.0%)
648 (0.3%) 42746 (22.9%) 136810 (73.2%) 5880 (3.1%) 878 (0.5%)
648 (0.3%) 42625 (22.9%) 136351 (73.2%) 5851 (3.1%) 878 (0.5%)
0 (0.0%) 90 (19.7%) 341 (74.6%) 26 (5.7%) 0 (0.0%)
0 (0.0%) 31 (20.4%) 118 (77.6%) 3 (2.0%) 0 (0.0%)
0.036
0.10
0.021
Pre-Op renal insufficiency No Yes Anticoagulation initiated of presumed/confirmed vein thrombosis/PE No Yes Pre-Op therapeutic anticoagulation No Yes Pre-Op vein thrombosis requiring therapy No Yes Pre-Op GERD requiring medication No Yes Previous cardiac surgery No Yes Pre-Op hypertensive requiring medication No Yes Previous obesity surgery/foregut surgery No Yes Pre-Op IVC Filter No Yes
0.028 186087 (99.5%) 875 (0.5%)
185485 (99.5%) 868 (0.5%)
451 (98.7%) 6 (1.3%)
151 (99.3%) 1 (0.7%)
Reference 2.83 (1.27, 6.32)
0.011
Reference 5.33 (2.76, 10.26)
<0.001
Reference 2.07 (1.39, 3.07)
<0.001
Reference 2.66 (1.68, 4.2)
<0.001
Reference 1.31 (1.08, 1.58)
0.006
Reference 2.22 (1.19, 4.15)
0.012
Reference 1.09 (0.91, 1.31)
0.34
Reference 10.35 (8.58, 12.48)
<0.001
Reference 2.22 (0.92, 5.35)
0.075
<0.001
186258 (99.6%) 704 (0.4%)
185660 (99.6%) 693 (0.4%)
448 (98.0%) 9 (2.0%)
150 (98.7%) 2 (1.3%)
181654 (97.2%) 5308 (2.8%)
181081 (97.2%) 5272 (2.8%)
431 (94.3%) 26 (5.7%)
142 (93.4%) 10 (6.6%)
<0.001
<0.001 183956 (98.4%) 3006 (1.6%)
183374 (98.4%) 2979 (1.6%)
438 (95.8%) 19 (4.2%)
144 (94.7%) 8 (5.3%)
127851 (68.4%) 59111 (31.6%)
127473 (68.4%) 58880 (31.6%)
285 (62.4%) 172 (37.6%)
93 (61.2%) 59 (38.8%)
0.003
0.034 185098 (99.0%) 1864 (1.0%)
184500 (99.0%) 1853 (1.0%)
447 (97.8%) 10 (2.2%)
151 (99.3%) 1 (0.7%) 0.13
99450 (53.2%) 87512 (46.8%)
99147 (53.2%) 87206 (46.8%)
233 (51.0%) 224 (49.0%)
70 (46.1%) 82 (53.9%) <0.001
162339 (86.8%) 24623 (13.2%)
162056 (87.0%) 24297 (13.0%)
178 (38.9%) 279 (61.1%)
105 (69.1%) 47 (30.9%) 0.18
186035 (99.5%) 927 (0.5%)
185432 (99.5%) 921 (0.5%)
452 (98.9%) 5 (1.1%)
151 (99.3%) 1 (0.7%)
Operative information procedure Bypass Others Sleeve Year of 0peration 2017 converted No conversion To open To other procedures
<0.001 44438 (23.8%) 20199 (10.8%) 122325 (65.4%)
44282 (23.8%) 19857 (10.7%) 122214 (65.6%)
85 (18.6%) 306 (67.0%) 66 (14.4%)
71 (46.7%) 36 (23.7%) 45 (29.6%)
186962 (100.0%)
186353 (100.0%)
457 (100.0%)
152 (100.0%)
Reference 7.92 (6.23, 10.07) 0.28 (0.2, 0.39)
186353 (99.7%) 457 (0.2%) 152 (0.1%)
*Association between no conversion (reference) vs converted to open; PR - prevalence ratio; SD – standard deviation; CI - confidence interval; BMI – body mass index; COPD – chronic obstructive pulmonary disease; IVC – inferior vena cava; MI – myocardial infarction; PCI/PTCA – percutaneous coronary intervention/percutaneous transcutaneous coronary angiography; ASA - American Society of Anesthesiologists; PE – pulmonary embolus; GERD – gastroesophageal reflux disease.
<0.001 <0.001
Table 2: Summary descriptive of postoperative complications Converted? Factor N Operation Length (minutes), median (IQR) Days to discharge, median (IQR) Death during operation No Yes Unplanned admission to ICU within 30 days No Yes Postoperative deep incisional surgical site infection (SSI) No Yes Deep incisional SSI present at time of surgery (PATOS) No Yes Intraoperative or postoperative myocardial infarction (MI) No Yes Postoperative organ space SSI No Yes Organ space SSI PATOS No Yes
Cohort 186962
No 186353
To Open 457
p-value
74.0 (52.0, 108.0) 1.0 (1.0, 2.0)
74.0 (51.0, 108.0) 1.0 (1.0, 2.0)
172.0 (120.0, 241.0) 4.0 (3.0, 7.0)
<0.001 <0.001 <0.001
186801 (99.9%) 161 (0.1%)
186200 (99.9%) 153 (0.1%)
450 (98.5%) 7 (1.5%)
PR (95% CI)*
p-value
2.21 (2.1, 2.3) 3.92 (3.5, 4.4)
<0.001 <0.001
18.15 (8.7, 37.7)
<0.001
15.3 (11.3, 20.7)
<0.001
37.93 (23.2, 62.0)
<0.001
117.82 (51.2, 271.1)
<0.001
22.34 (15.5, 32.2)
<0.001
48.72 (26.2, 90.6)
<0.001
<0.001 185634 (99.3%) 1328 (0.7%)
185074 (99.3%) 1279 (0.7%)
412 (90.2%) 45 (9.8%) <0.001
186794 (99.9%) 168 (0.1%)
186201 (99.9%) 152 (0.1%)
442 (96.7%) 15 (3.3%) <0.001
186948 (100.0%) 14 (<1%)
186343 (100.0%) 10 (<1%)
453 (99.1%) 4 (0.9%) 0.72
186910 (100.0%) 52 (<1%)
186301 (100.0%) 52 (<1%)
457 (100.0%) 0 (0.0%) <0.001
186396 (99.7%) 566 (0.3%)
185817 (99.7%) 536 (0.3%)
428 (93.7%) 29 (6.3%) <0.001
186885 (100.0%) 77 (<1%)
186285 (100.0%) 68 (<1%)
448 (98.0%) 9 (2.0%)
Number of postoperative pneumonia occurrences
<0.001 0 1
Pneumonia PATOS No Yes Progressive renal insufficiency No Yes Pulmonary embolism No Yes Postoperative sepsis No Yes Sepsis PATOS No Yes Number of postoperative septic shock occurrences
185957 (99.8%) 396 (0.2%)
445 (97.4%) 12 (2.6%)
12.32 (7.0, 21.7)
<0.001
20.87 (9.5, 45.8)
<0.001
10.12 (4.2, 24.2)
<0.001
28.38 (17.8, 45.3)
<0.001
51.54 (20.5, 129.5)
<0.001
28.6 (15.6, 52.4)
<0.001
184.9 (109.4, 312.5)
<0.001
14.47 (10.1, 20.7)
<0.001
0.85 186948 (100.0%) 14 (<1%)
186339 (100.0%) 14 (<1%)
457 (100.0%) 0 (0.0%) <0.001
186843 (99.9%) 119 (0.1%)
186240 (99.9%) 113 (0.1%)
451 (98.7%) 6 (1.3%) <0.001
186758 (99.9%) 204 (0.1%)
186154 (99.9%) 199 (0.1%)
452 (98.9%) 5 (1.1%) <0.001
186707 (99.9%) 255 (0.1%)
186116 (99.9%) 237 (0.1%)
440 (96.3%) 17 (3.7%) <0.001
186930 (100.0%) 32 (<1%)
186325 (100.0%) 28 (<1%)
453 (99.1%) 4 (0.9%) <0.001
0 1 Septic shock PATOS No Yes Postoperative superficial incisional SSI No Yes Superficial incisional SSI PATOS
186554 (99.8%) 408 (0.2%)
186815 (99.9%) 147 (0.1%)
186217 (99.9%) 136 (0.1%)
447 (97.8%) 10 (2.2%)
186944 (100.0%) 18 (<1%)
186343 (100.0%) 10 (<1%)
449 (98.2%) 8 (1.8%)
<0.001
<0.001 186026 (99.5%) 936 (0.5%)
185449 (99.5%) 904 (0.5%)
426 (93.2%) 31 (6.8%) <0.001
No Yes Transfusion intraoperative/postoperative (72 hours of surgery start time) No Yes Number of units transfused (1-200), median (IQR) Bleeding units 1 2 3 Unplanned intubation No Yes Postoperative urinary tract infection (UTI) No Yes UTI PATOS No Yes Postoperative vein thrombosis requiring therapy No Yes Wound disruption No Yes Unplanned admission to ICU within 30 days
186941 (100.0%) 21 (<1%)
186336 (100.0%) 17 (<1%)
453 (99.1%) 4 (0.9%)
78.54 (32.4, 190.6)
<0.001
16.21 (11.9, 22.0)
<0.001
0.76 (0.4, 1.6) 1.09 (0.5, 2.4)
0.48 0.828
18.23 (9.9, 33.7)
<0.001
4.2 (2.0, 8.9)
<0.001
21.65 (7.2, 65.4)
<0.001
3.85 (1.2, 11.9)
0.019
20.19 (9.2, 44.3)
<0.001
<0.001 185740 (99.3%) 1222 (0.7%) 2.0 (2.0, 3.0)
185177 (99.4%) 1176 (0.6%) 2.0 (2.0, 3.0)
413 (90.4%) 44 (9.6%) 2.0 (2.0, 3.0)
0.61 0.55
258 (0.1%) 606 (0.3%) 352 (0.2%) 185746 (99.3%)
246 (0.1%) 588 (0.3%) 337 (0.2%) 185182 (99.4%)
10 (2.2%) 18 (3.9%) 15 (3.3%) 414 (90.6%) <0.001
186733 (99.9%) 229 (0.1%)
186134 (99.9%) 219 (0.1%)
447 (97.8%) 10 (2.2%) <0.001
186271 (99.6%) 691 (0.4%)
185670 (99.6%) 683 (0.4%)
450 (98.5%) 7 (1.5%) <0.001
186905 (100.0%) 57 (<1%)
186299 (100.0%) 54 (<1%)
454 (99.3%) 3 (0.7%) 0.012
186641 (99.8%) 321 (0.2%)
186036 (99.8%) 317 (0.2%)
454 (99.3%) 3 (0.7%)
186839 (99.9%) 123 (0.1%)
186236 (99.9%) 117 (0.1%)
451 (98.7%) 6 (1.3%)
<0.001
<0.001
No Yes Acute renal failure (ARF) No Yes Intraoperative or postoperative cardiac arrest requiring CPR No Yes Morbidity No Yes Readmission within 30 days of operation No Yes Reoperation within 30 days of operation No Yes Revision within 30 days of operation No Yes Intervention within 30 days of operation No Yes
185634 (99.3%) 1328 (0.7%)
185074 (99.3%) 1279 (0.7%)
412 (90.2%) 45 (9.8%)
15.3 (11.3, 20.7)
<0.001
6.84 (1.7, 27.1)
0.006
26.15 (11.1, 61.4)
<0.001
17.14 (14.1, 20.8)
<0.001
5.74 (4.5, 7.3)
<0.001
12.23 (9.5, 15.8)
<0.001
7.97 (6.6, 9.6)
<0.001
6.94 (5.0, 9.7)
<0.001
0.002 186842 (99.9%) 120 (0.1%)
186235 (99.9%) 118 (0.1%)
455 (99.6%) 2 (0.4%) <0.001
186883 (100.0%) 79 (<1%)
186279 (100.0%) 74 (<1%)
452 (98.9%) 5 (1.1%) <0.001
181723 (97.2%) 5239 (2.8%)
181275 (97.3%) 5078 (2.7%)
306 (67.0%) 151 (33.0%) <0.001
179993 (96.3%) 6969 (3.7%)
179479 (96.3%) 6874 (3.7%)
374 (81.8%) 83 (18.2%) <0.001
184411 (98.6%) 2551 (1.4%)
183876 (98.7%) 2477 (1.3%)
391 (85.6%) 66 (14.4%) <0.001
179993 (96.3%) 6969 (3.7%)
179479 (96.3%) 6874 (3.7%)
374 (81.8%) 83 (18.2%) <0.001
184619 (98.7%) 2343 (1.3%)
184049 (98.8%) 2304 (1.2%)
420 (91.9%) 37 (8.1%)
*Association between no conversion (reference) vs converted to open; PR - prevalence ratio; CI – confidence interval; IQR – interquartile range; intensive care unit – ICU; CPR – cardiopulmonary resuscitation.
Table 3: Adjusted Associations
Operation Length; RC (95% CI)+ Days to discharge from operation; RC (95% CI)++ Death* Morbidity** Re – operation*** Re – intervention**** Re – admission*****
OR 94.92 4.81 7.52 11.54 6.97 4.28 4.01
95% CI P value 89.39 100.44 <0.001 4.65 4.96 <0.001 2.84 9.00 5.02 2.84 2.97
19.91 14.80 9.69 6.44 5.41
<0.001 <0.001 <0.001 <0.001 <0.001
OR: odds ratio; CI: confidence interval; modelled for converted to open vs. no conversion (reference); RC- regression coefficient. +Adjusted for : Age, BMI (body mass index), Albumin, HCT (hematocrit), Race, hyperlipidemia, oxygen dependency, mobility device, history of DVT (deep venous thrombosis), functional health status, GERD (gastroesophageal reflux disease), previous surgery, venous status, smoker, IVC (inferior vena cava) filter, ASACLASS (American Society of Anesthesiologist Classification), renal insufficiency, anticoagulation, therapeutic anticoagulation; ++Adjusted for: Age, BMI, albumin, HCT, Race, hyperlipidemia, oxygen dependency, mobility device, functional health status, history of DVT, PTC (percutaneous transluminal coronary angiography), previous surgery, IVC filter, GERD, ASACLASS, PCARD (previous cardiac surgery), renal insufficiency, Anticoagulation, therapeutic anticoagulation; *Adjusted for: Age, BMI, history of DVT, HCT, Race, ASACLASS, oxygen dependency, anticoagulation, PTC, Previous surgery, therapeutic anticoagulation; **Adjusted for: Age, BMI, Albumin, HCT, ASACLASS, Race, History of DVT, hyperlipidemia, oxygen dependency, mobility device, GERD, renal insufficiency, PTC, previous surgery, venous status, anticoagulation, therapeutic anticoagulation; ***Adjusted for: Age, BMI, Albumin, Anticoagulation, Race, GERD, smoker, oxygen dependency, ASACLASS, functional health status, History DVT, previous surgery, therapeutic anticoagulation; ****Adjusted for: Age, anticoagulation, Albumin, HCT, therapeutic, Race, IVC filter, PCARD, mobility device, GERD, functional health status, ASACLASS, previous surgery; *****Adjusted for: ASACLASS, GERD, Albumin, HCT, therapeutic anticoagulation, Race, hyperlipidemia, oxygen dependency, mobility, functional health status, renal insufficiency, PCARD, previous surgery, anticoagulation, smoker, history of DVT.
Table 4: Adjusted analysis on propensity matched cohort OR
95% CI
P value
<0.001 98.41 86.06 110.76 Operation Length; RC (95% CI) Days to discharge from operation; RC (95% 3.80 5.66 <0.001 4.73 CI) 1.88 1.67 2.11 <0.001 Death 4.63 3.08 6.96 <0.001 Morbidity 6.42 2.92 14.11 <0.001 Re – operation 3.75 1.65 8.53 0.002 Re – intervention 2.65 1.72 4.1 <0.001 Re – admission OR: odds ratio; CI: confidence interval; modelled for converted to open vs. no conversion (reference); RC- regression coefficient. Adjusted for: Diabetes, myocardial infarction, and American Society of Anesthesiologist Classification.
Highlights: This paper uses data from the MBSAQIP database to evaluate the outcomes of patients undergoing metabolic and bariatric surgery that were converted from a minimally invasive technique to open surgery. They have higher rates of morbidity and mortality.